User`s Manual
User’s Manual
Intuitive satellite systems analysis
software designed to assist in
visualizing and analyzing complex
relationships in space systems
VERSION 4.0 FOR ENGINEERING
WORKSTATIONS
AUTHORS: SHEILA R. MARSHALL
RALPH C. PATRICK
ANALYTICAL GRAPHICS, INC.
660 American Avenue
King of Prussia, PA 19406
GS01-MO40-AG05-070797
This document and the software described in it are the proprietary and tradesecret information of Analytical Graphics, Incorporated. They are provided
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license agreement between Analytical Graphics, Incorporated and its
customer, and may not be transferred, disclosed or otherwise provided to
third parties, unless otherwise permitted by that agreement. Use,
reproduction or publication of any portion of this material without the prior
written authorization of Analytical Graphics, Incorporated is prohibited.
While reasonable efforts have been taken in the preparation of this manual to
ensure accuracy, Analytical Graphics, Incorporated assumes no liability
resulting from any errors or omissions in this manual, or from the use of the
information contained herein.
Copyright © 1997 Analytical Graphics, Incorporated.
All Rights Reserved.
Satellite Tool Kit (STK)® is a registered trademark of Analytical Graphics,
Incorporated. The Analytical Graphics name and triangle logo design are
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duplication or disclosure by the Government is subject to restrictions set
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Satellite Tool Kit® Software License Agreement
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Copyright 1995 BertBos
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By:
Title:
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STK USER’S MANUAL
TABLE OF
CONTENTS
INTRODUCTION .......................................................................................1-1
Who Should Use This Manual?........................................................................1-2
How This Manual Is Organized........................................................................1-2
Conventions Used in This Manual ...................................................................1-8
STK Professional Features .................................................................................1-9
Advanced Analysis .......................................................................................1-9
High Precision Orbit Propagator (HPOP) ...................................................1-11
Long-term Orbit Predictor (LOP) ................................................................1-13
Lifetime ......................................................................................................1-14
Terrain........................................................................................................1-14
High Resolution Maps................................................................................1-15
Additional Resources......................................................................................1-15
USER INTERFACE ......................................................................................2-1
Starting & Quitting STK.....................................................................................2-3
The Browser Window......................................................................................2-3
Object Menu ...............................................................................................2-5
Opening & Closing a Scenario.........................................................................2-5
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Creating a New Object....................................................................................2-6
Inserting an Existing Object into a Scenario.....................................................2-6
Last Loaded Function ..................................................................................2-8
Linking an Object into a Scenario................................................................2-8
Saving an Object .............................................................................................2-8
Saving to a Different Directory .....................................................................2-9
Saving a Modified Object ..........................................................................2-10
Saving the Scenario without Children........................................................2-10
Removing an Object from a Scenario............................................................2-10
Setting Up the Printer.....................................................................................2-11
2D Map .....................................................................................................2-11
Reports & Graphs.......................................................................................2-13
Selecting a File ...............................................................................................2-14
Editing in STK .................................................................................................2-15
Opening an STK Module or External Application...........................................2-15
Defining the Properties of an Object..............................................................2-15
The Property Windows..............................................................................2-16
Describing an Object in STK.......................................................................2-17
Using Multiple Windows................................................................................2-17
Using STK Tools..............................................................................................2-17
Using Help.....................................................................................................2-18
Making Choices in STK ...................................................................................2-18
Selecting Multiple Objects..........................................................................2-18
Toggle Buttons ..........................................................................................2-19
Option Menus ...........................................................................................2-20
Radio Buttons ............................................................................................2-20
Lists ............................................................................................................2-20
Using Accelerator Keys...................................................................................2-21
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THE MAP WINDOW .................................................................................3-1
The Tool Bar.....................................................................................................3-3
Animation Time Steps.......................................................................................3-4
Map Properties.................................................................................................3-5
Map Attributes .............................................................................................3-5
Map Details..................................................................................................3-6
Map Projection ............................................................................................3-9
Map Background.......................................................................................3-14
Text Annotation .........................................................................................3-15
Status Bar .......................................................................................................3-17
Animating a Scenario.....................................................................................3-18
Animation and its Relationship to Vehicle Tracks .......................................3-18
STK APPLICATION......................................................................................4-1
Basic Properties: STK Save Prefs ........................................................................4-2
Basic Properties: IPC Preferences ......................................................................4-3
Basic Properties: Online Operations.................................................................4-5
SCENARIOS ...............................................................................................5-1
Basic Properties: Setting the Time Period..........................................................5-2
Basic Properties: Setting Animation Options ....................................................5-4
Basic Properties: Setting Units of Measure........................................................5-7
Entering Units in Text Fields .......................................................................5-11
Basic Properties: Setting Default Databases....................................................5-11
Basic Properties: Terrain .................................................................................5-12
Adding Terrain Elevation Data...................................................................5-13
Graphics Properties: Global Attributes............................................................5-14
Graphics Properties: Sun Lighting..................................................................5-16
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SATELLITES ................................................................................................6-1
Basic Properties: Orbit ......................................................................................6-3
Two-Body, J2 Perturbation & J4 Perturbation Propagators..............................6-3
Orbit Epoch .................................................................................................6-4
Coordinate Epoch .......................................................................................6-4
Coordinate Type ..........................................................................................6-4
Coordinate Systems - Standard ..................................................................6-12
Coordinate Systems - Advanced Analysis Module......................................6-13
Special Options..........................................................................................6-14
HPOP Propagator (Module)...........................................................................6-15
Force Models .............................................................................................6-15
Long-term Orbit Predictor (Module)...............................................................6-18
Force Models .............................................................................................6-18
MSGP4 Propagator ........................................................................................6-22
Managing TLE Sets ....................................................................................6-24
Custom Propagator (StkExternal) ...................................................................6-27
Basic Properties: Attitude................................................................................6-28
Attitude Type Selection...............................................................................6-29
Orientation Type........................................................................................6-34
Integrated Attitude.....................................................................................6-35
Target Pointing ..........................................................................................6-36
Basic Properties: Pass Break............................................................................6-38
Basic Properties: Mass ....................................................................................6-40
Graphics Properties: Attributes .......................................................................6-41
Graphics Properties: Pass ...............................................................................6-42
Graphics Properties: Display Times.................................................................6-44
Graphics Properties: Contours .......................................................................6-45
Constraints: Basic ...........................................................................................6-47
Constraints: Sun.............................................................................................6-50
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Constraints: Temporal ....................................................................................6-52
Constraints: Advanced...................................................................................6-54
SHIPS, AIRCRAFT & GROUND VEHICLES...................................................7-1
Route ...............................................................................................................7-2
Attitude ............................................................................................................7-4
External Attitude File ....................................................................................7-6
Graphics Properties: Attributes .........................................................................7-6
Graphics Properties: Display Times...................................................................7-8
Aircraft, Ground Vehicle & Ship Constraints.....................................................7-9
Constraints: Advanced - Aircraft Only.............................................................7-10
LAUNCH VEHICLES & MISSILES.................................................................8-1
Basic Properties: Trajectory...............................................................................8-2
Simple Ascent Propagator (Launch Vehicles)...............................................8-2
Ballistic Propagator (Missiles) ........................................................................8-3
External Propagator.....................................................................................8-5
Basic Properties: Attitude..................................................................................8-6
External Attitude File ....................................................................................8-7
Graphics Properties: Attributes .........................................................................8-7
Graphics Properties: Display Times...................................................................8-9
Graphics Properties: Contours .......................................................................8-10
Level Adding..............................................................................................8-11
Level Attributes...........................................................................................8-12
Launch Vehicle & Missile Constraints .............................................................8-12
FACILITIES & TARGETS ...............................................................................9-1
Basic Properties: Position..................................................................................9-2
Geodetic Position.........................................................................................9-3
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Spherical Position.........................................................................................9-4
Cartesian Position.........................................................................................9-4
Cylindrical Position .......................................................................................9-5
Geocentric Position......................................................................................9-5
Basic Properties: Az-El Mask..............................................................................9-6
Graphics Properties: Attributes .........................................................................9-6
Graphics Properties: Az-El Mask........................................................................9-8
Graphics Properties: Display Times...................................................................9-9
Constraints: Basic ...........................................................................................9-10
Constraints: Sun.............................................................................................9-13
Constraints: Temporal ....................................................................................9-16
AREA TARGETS ........................................................................................10-1
Basic Properties: Boundary.............................................................................10-2
Basic Properties: Centroid...............................................................................10-3
Geodetic Position.......................................................................................10-4
Spherical Position.......................................................................................10-4
Cartesian Position.......................................................................................10-5
Cylindrical Position .....................................................................................10-5
Geocentric Position....................................................................................10-5
Graphics Properties: Attributes .......................................................................10-6
Constraints: Basic ...........................................................................................10-7
Constraints: Temporal ....................................................................................10-9
STARS & PLANETS....................................................................................11-1
Basic Properties: Defining a Star.....................................................................11-2
Basic Properties: Defining a Planet .................................................................11-3
Graphic Properties: Star/Planet Attributes.......................................................11-4
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Satellite Tool Kit® User's Manual
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SENSORS.................................................................................................12-1
Basic Properties: Definition.............................................................................12-2
Conic Sensor..............................................................................................12-3
Half-Power Sensor......................................................................................12-4
Custom Sensor...........................................................................................12-6
Rectangular Sensor....................................................................................12-8
Basic Properties: Pointing a Sensor.................................................................12-9
Fixed Sensor Pointing ..............................................................................12-10
Targeting a Sensor...................................................................................12-13
External Pointing Files ..............................................................................12-16
Basic Properties: Resolution..........................................................................12-16
Graphics Properties: Sensor Attributes..........................................................12-17
Graphics Properties: Projection ....................................................................12-18
Graphics Properties: Display Times...............................................................12-20
Constraints: Basic .........................................................................................12-21
Constraints: Sun...........................................................................................12-22
Constraints: Temporal ..................................................................................12-24
Constraints: Advanced.................................................................................12-24
Constraints: Resolution.................................................................................12-25
USING STK TOOLS ..................................................................................13-1
Access ............................................................................................................13-3
Calculating Access between Objects .........................................................13-3
Setting Access Graphics for the Map Window...........................................13-5
Generating Access Reports ........................................................................13-6
Viewing Azimuth, Elevation and Range Data for Access ...........................13-7
Using the Custom and Dynamic Display Options .....................................13-8
Creating Graphs for Access Data ...............................................................13-8
Removing Accesses from the Map Window..............................................13-9
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Accesses and Their Defining Objects .......................................................13-10
Lighting........................................................................................................13-11
Viewing the AER Report...........................................................................13-13
Viewing a Time Data Report....................................................................13-13
Lifetime (Module) .........................................................................................13-14
Advanced ................................................................................................13-17
Computing Lifetime .................................................................................13-19
Lifetime Results.........................................................................................13-20
Report......................................................................................................13-21
Graph ......................................................................................................13-22
Swath (Advanced Analysis Module).............................................................13-23
Vehicle Swath..........................................................................................13-23
Sensor Swath...........................................................................................13-25
Walker Constellation ....................................................................................13-26
Remove Accesses.....................................................................................13-29
Close Approach Tool (Module) ....................................................................13-29
Time Period..............................................................................................13-31
Access Constraint.....................................................................................13-31
Search Constraint.....................................................................................13-32
Advanced Options...................................................................................13-32
Computing Close Approaches.................................................................13-34
Export Shapefile Tool....................................................................................13-35
Change Icon Tool ........................................................................................13-35
CITY, FACILITY, SATELLITE & STAR DATABASES........................................14-1
City Database.................................................................................................14-2
Querying a Database ................................................................................14-3
Viewing Search Results ..............................................................................14-4
Object Description.....................................................................................14-5
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Facility Database ............................................................................................14-5
Querying a Database ................................................................................14-6
Viewing Search Results ..............................................................................14-7
Object Description.....................................................................................14-8
Satellite Database ...........................................................................................14-8
Querying a Database ..............................................................................14-10
Viewing Search Results ............................................................................14-11
Online Update.........................................................................................14-12
Object Description...................................................................................14-14
Star Database...............................................................................................14-14
Querying a Database ..............................................................................14-15
Viewing Search Results ............................................................................14-17
Object Description...................................................................................14-17
Load TLE ......................................................................................................14-18
Loading a Satellite TLE..............................................................................14-18
Loading a Facility TLE...............................................................................14-20
Object Description...................................................................................14-22
REPORTS & GRAPHS................................................................................15-1
Using the STK Report/Graph Tool..................................................................15-2
Changing Time Periods for Reports & Graphs ...........................................15-3
Managing Report/Graph Styles .................................................................15-4
Report Window .............................................................................................15-5
Report Properties............................................................................................15-6
Content......................................................................................................15-7
Header.....................................................................................................15-11
Graph Window ...........................................................................................15-12
Graph Properties..........................................................................................15-15
Content....................................................................................................15-15
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Table of Contents
Layout......................................................................................................15-17
DYNAMIC DISPLAYS & STRIP CHARTS......................................................16-1
Overview .......................................................................................................16-1
Chapter Contents...........................................................................................16-1
The STK Dynamic Display/Strip Chart Tool Window ......................................16-2
Managing Dynamic Display/Strip Chart Styles...........................................16-3
Dynamic Display Window .............................................................................16-4
Dynamic Display Properties............................................................................16-5
Content......................................................................................................16-6
Strip Chart Window .......................................................................................16-8
Strip Chart Properties....................................................................................16-10
Content....................................................................................................16-11
Layout......................................................................................................16-13
USING THE STK HELP MENU..................................................................17-1
STK Help Topics..............................................................................................17-2
Selecting an HMTL Browser.......................................................................17-2
Opening Help from the Browser Window................................................17-3
Opening Help from a Property Window...................................................17-3
Licensing........................................................................................................17-3
Password Window (Initial Start-Up)............................................................17-4
Requesting Licenses by E-Mail or FAX ........................................................17-5
Entering Licenses .......................................................................................17-6
Network Passwords...................................................................................17-8
On-Line Manuals............................................................................................17-9
About STK.......................................................................................................17-9
AGI Web Site..................................................................................................17-9
Other Help Menu Items .................................................................................17-9
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Satellite Tool Kit® User's Manual
Table of Contents
CHAINS MODULE...................................................................................18-1
Overview .......................................................................................................18-1
Chains & Constellations..................................................................................18-2
Basic Properties of a Chain.............................................................................18-3
Definition ...................................................................................................18-4
Constellations.................................................................................................18-5
Basic Properties of a Constellation..................................................................18-6
Constellation..............................................................................................18-6
Generating Reports for a Chain .....................................................................18-8
Creating Graphs for Chains .........................................................................18-12
Dynamic Display Reports & Strip Charts .......................................................18-13
GLOSSARY OF TERMS ...............................................................................A-1
DEFINING CUSTOM SENSOR PATTERNS..................................................B-1
The Reference Plane Format ............................................................................B-2
The Az-El Mask Format.....................................................................................B-7
The Angle-Off-Boresight Format.......................................................................B-9
IMPORTING FILES INTO STK......................................................................C-1
Overview .........................................................................................................C-1
Attitude File Format..........................................................................................C-3
Az-El File (.aem) Format....................................................................................C-8
Custom Sensor File Format ..............................................................................C-9
Ephemeris File Format (.e) ...............................................................................C-9
Planetary Ephemeris File (.pe) Format........................................................... C-17
Torque File (.tq) Format ................................................................................ C-18
Color Bitmap/Pixmap (.bmp/.xpm) File Format ............................................ C-19
Database File Formats................................................................................... C-20
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Satellite Database...................................................................................... C-20
TLE File Format.......................................................................................... C-26
City Database............................................................................................ C-29
Facility Database ....................................................................................... C-32
Star Database............................................................................................ C-34
Solar Flux Files ............................................................................................... C-38
HPOP TECHNICAL NOTES ....................................................................... D-1
Technical Notes............................................................................................... D-1
HPOP Values................................................................................................... D-2
HIGH-RESOLUTION MAPS TECHNICAL NOTES ........................................ E-1
Definitions........................................................................................................E-2
RWDB2 Features..............................................................................................E-3
Coastlines.....................................................................................................E-3
Islands..........................................................................................................E-4
Lakes............................................................................................................E-4
Rivers............................................................................................................E-5
International Boundaries..............................................................................E-6
Provincial Boundaries...................................................................................E-8
List of Figures
Figure 2-1. Typical Browser window..................................................................... 2-4
Figure 2-2. Typical Insert window. ........................................................................ 2-7
Figure 2-3. Satellite Pass tab illustrating toggle buttons, radio buttons and option
menus. .......................................................................................................2-19
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Figure 3-1. The Map window. ............................................................................. 3-2
Figure 3-2. Map window with texture background.............................................3-15
Figure 3-3. Status bar in Map window ................................................................3-17
Figure 6-1. Classical coordinate relationships ........................................................ 6-7
Figure 6-2. Satellite elevation angle constraint ....................................................6-49
Figure 6-3. Satellite exclusion zone constraint .....................................................6-57
Figure 12-1. Extended cone ...............................................................................12-4
Figure 12-2 . Half-power cone............................................................................12-6
Figure 12-3 . Custom pattern cone .....................................................................12-8
Figure 13-1. A typical Map window showing access between the ERS1 satellite and
the Santiago facility.....................................................................................13-5
Figure 13-2. A sample Access Report showing access data for the ERS1 satellite to
the Santiago facility.....................................................................................13-6
Figure 13-3. A sample AER Report showing access data for ERS1 to the Santiago
facility. ........................................................................................................13-7
Figure 13-4. A sample Graph Data window showing access data for the ERS1
satellite to the Santiago facility.....................................................................13-9
Figure 13-5. Diagram showing access scheme for targeted sensors..................13-11
Figure 13-6. A sample AER Report showing lighting data for the Shuttle...........13-13
Figure 13-7. A sample Lighting Times Report for the Shuttle. ............................13-14
Figure 13-8. Sample Lifetime report summarizing Keplerian elements .............13-21
Figure 13-9 . Sample Lifetime graph showing the evolution of the orbital parameters
height of apogee, height of perigee and inclination .................................13-22
Figure 13-10. The Map window showing a Walker seed satellite and its children
(two planes each with two satellites).........................................................13-28
Figure 13-11. Walker Constellation clearly illustrating the satellite configuration.13-28
Figure 15-1. An example of the STK Report Tool window. ..................................15-2
Figure 15-2 . Sample report summarizing J2000 x, y, and z position for the ERS1
and Shuttle vehicles ....................................................................................15-5
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Figure 15-3. Sample X,Y Graph that displays the azimuth, elevation and range of the
Sun relative to the ERS1 vehicle.................................................................15-12
Figure 16-1. An example of the STK Dynamic Display Tool window...................16-3
Figure 16-2. A sample standard dynamic display showing J2000 position and
velocity data for the ERS1 vehicle. The data changes as the animation moves
forward or backward in time. .....................................................................16-5
Figure 16-3. A sample standard strip chart showing ECF position and velocity data
for the ERS1 vehicle. ...................................................................................16-8
Figure 18-1. A simple chain defined as Target- LEO - Relay - Ground Station. Picture
captured in STK’s Visualization Option (VO) module....................................18-3
Figure 18-2. A more complex chain defined as 2 Targets - Leo - 2 Relays - 2 Ground
Stations. Picture captured in STK’s Visualization Option (VO) module. ........18-5
Figure 18-3. Diagram showing possible strand accesses from both Target1 and Target2 to Leo
to both Relay1 and Relay2 to GroundStation. Individual strand access for Target1-Relay2GroundStation is shown in bold. .......................................................................18-9
Figure 18-4. Diagram showing individual object access for Relay1 (access shown in
bold lines). ................................................................................................18-10
Figure 18-5. Sample Graph showing accesses for each individual strand and object
in the Chain as well as complete access. ...................................................18-12
Figure 18-6. Graph window displaying angle between objects in the chain.....18-13
Figure B-1. The desired relative geometry of the satellite and the custom sensor
pattern.......................................................................................................... B-3
Figure B-2. Polar coordinate paper showing the sensor coordinates..................... B-4
Figure B-3. Definition of the elevation angle......................................................... B-7
Figure B-4. Polar projection for the Az-El Mask format. .......................................... B-8
Figure B-5. Polar projection for the Angle-Off-Boresight format...........................B-10
List of Tables
Table 2-1. 2D Map print options .........................................................................2-12
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Table 2-2. Additional print options for reports & graphs ......................................2-14
Table 2-3. Accelerator keys..................................................................................2-21
Table 3-1. Tool bar buttons ................................................................................... 3-3
Table 3-2. Map display options.............................................................................. 3-6
Table 3-3. Options for Map details ........................................................................ 3-7
Table 3-4. Basic projection types .........................................................................3-10
Table 3-5. Advanced projection types .................................................................3-11
Table 3-6. Text annotation position options ........................................................3-16
Table 4-1. Save preferences .................................................................................. 4-2
Table 4-2. IPC preferences..................................................................................... 4-4
Table 4-3. Online preferences ............................................................................... 4-5
Table 5-1. Time period options ............................................................................. 5-4
Table 5-2. Animation options ................................................................................ 5-5
Table 5-3. Units options ........................................................................................ 5-8
Table 5-4. Database options................................................................................5-12
Table 5-5. Global attributes .................................................................................5-15
Table 5-6. Sun lighting options ...........................................................................5-16
Table 6-1. Description of classical orbital elements ................................................ 6-5
Table 6-2. Equinoctial coordinate type elements ................................................... 6-9
Table 6-3. Mixed spherical coordinate type elements ..........................................6-10
Table 6-4. Spherical elements..............................................................................6-11
Table 6-5. Standard coordinate systems ..............................................................6-12
Table 6-6. AAM Coordinate systems ....................................................................6-13
Table 6-7. Ellipse options ....................................................................................6-14
Table 6-8. Force model options ..........................................................................6-16
Table 6-9.Atmospheric Density Models................................................................6-17
Table 6-10. Force model options ........................................................................6-19
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Table 6--11. MSGP4 orbital elements....................................................................6-23
Table 6--12. TLE selection options ........................................................................6-25
Table 6--13. TLE advanced options ......................................................................6-27
Table 6--14. Standard attitude types.....................................................................6-30
Table 6--15. Other Attitude types (Advanced Analysis Module) .............................6-31
Table 6--16. Orientation types.............................................................................6-34
Table 6--17. Integrated attitude options ...............................................................6-35
Table 6--18. Pass Break fields................................................................................6-39
Table 6--19. Options in the Attributes tab .............................................................6-41
Table 6--20. Options in the Pass tab .....................................................................6-43
Table 6--21. Satellite basic constraints...................................................................6-48
Table 6--22. Satellite Sun constraints.....................................................................6-51
Table 6--23. Satellite temporal constraints.............................................................6-53
Table 6--24. Satellite advanced constraints ...........................................................6-55
Table 7--1. Great Arc propagator elements............................................................. 7-3
Table 7--2. Attitude types ....................................................................................... 7-5
Table 7--3. Options in the Attributes tab ................................................................. 7-7
Table 7--4. Aircraft advanced constraints ..............................................................7-11
Table 8--1. Simple Ascent propagator elements...................................................... 8-3
Table 8--2. Ballistic propagator elements ................................................................ 8-4
Table 8--3. Attitude types ....................................................................................... 8-6
Table 8--4. Options in the Attributes tab ................................................................. 8-8
Table 9-1. Geodetic facility/target options ............................................................. 9-3
Table 9-2. Spherical facility/target options ............................................................. 9-4
Table 9-3. Cartesian facility/target options............................................................. 9-4
Table 9-4. Cylindrical facility/target options ........................................................... 9-5
Table 9-5. Geocentric facility/target options .......................................................... 9-5
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Table 9-6. Facility/target graphic attributes............................................................ 9-7
Table 9-7. Facility/target azimuth-elevation mask graphics .................................... 9-8
Table 9-8. Facility/target basic constraints ...........................................................9-11
Table 9-9. Facility/target Sun constraints .............................................................9-14
Table 9-10. Facility/target temporal constraints ...................................................9-17
Table 10-1. Geodetic area target fields................................................................10-4
Table 10-2. Spherical area target options ............................................................10-4
Table 10-3. Cartesian area target options ............................................................10-5
Table 10-4. Cylindrical area target options ..........................................................10-5
Table 10-5. Geocentric area target options .........................................................10-6
Table 10--6. Area target atributes .........................................................................10-7
Table 10-7. Basic constraints for an area target ...................................................10-8
Table 10-8. Area target temporal options ............................................................10-9
Table 11-1. Star definition options.......................................................................11-2
Table 11-2. Planet definition elements ................................................................11-4
Table 11-3. Star/planet graphic attributes............................................................11-5
Table 12-1. Conic sensor options ........................................................................12-3
Table 12-2. Half-power sensor options................................................................12-5
Table 12-4. Orientation methods ......................................................................12-11
Table 12-5. About Boresight settings.................................................................12-11
Table 12-6. Sensor graphics attributes...............................................................12-18
Table 12-7. Sensor Sun constraints....................................................................12-23
Table 13-1. Access graphics options....................................................................13-5
Table 13-2. Lighting options .............................................................................13-12
Table 13-3. Lifetime options ..............................................................................13-16
Table 13-4. Advanced options for Lifetime ........................................................13-18
Table 13-5. Vehicle swath options ....................................................................13-24
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Table of Contents
Table 13-6. Swath options ................................................................................13-25
Table 13-7. Options for a Walker constellation ..................................................13-26
Table 13-8. Satellite spacing for sample Walker satellites....................................13-29
Table 14-1. City Database options.......................................................................14-4
Table 14-2. City Database search results options .................................................14-5
Table 14-3. Facility Database options ..................................................................14-6
Table 14-4. Facility Database search results options.............................................14-7
Table 14-5. Satellite Database options ...............................................................14-10
Table 14-6. Satellite Database search results options .........................................14-12
Table 14-7. Online Satellite Database update options........................................14-13
Table 14-8. Star database options .....................................................................14-16
Table 14-9. Star Database search results options ...............................................14-17
Table 14-10. TLE load results options ................................................................14-20
Table 14-11. Facility TLE Load options...............................................................14-21
Table 15-1. STK report/graph tool functions........................................................15-4
Table 15-2. Files menu options for report windows ............................................15-6
Table 15-3. Section options.................................................................................15-9
Table 15-4. Data element options .....................................................................15-10
Table 15-5. Report Header options ...................................................................15-11
Table 15-6. Graph Data buttons .......................................................................15-13
Table 15-7. Graph attribute options ..................................................................15-14
Table 15-8. Graph type options ........................................................................15-16
Table 15-9. Graph element options ..................................................................15-17
Table 15-10. Graph layout options ...................................................................15-18
Table 16-1. STK dynamic display/strip chart tool functions...................................16-4
Table 16-2. Files menu options for dynamic display windows .............................16-5
Table 16-3. Dynamic display options...................................................................16-7
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Table 16-4. Strip Chart data buttons....................................................................16-9
Table 16-5. Strip chart attribute options ............................................................16-10
Table 16-6. Graph element options ..................................................................16-12
Table 16-7. Strip chart layout options................................................................16-13
Table 17-1. Password options .............................................................................17-4
Table 17-2. Request for licenses via e-mail/fax .....................................................17-6
Table 17-3. License window options...................................................................17-7
Table 17-4. Additional Help menu items ...........................................................17-10
Table 18-1. Constellation criteria options............................................................18-7
Table B-1. Polar coordinates.................................................................................. B-5
Table C-1. Keywords for Attitude ...........................................................................C-3
Table C-2. Keywords for Ephemeris file format ....................................................C-10
Table C-3. stkActiveTLE database files ..................................................................C-21
Table C-4. stkActiveTLE.sd file description ............................................................C-21
Table C-5. stkActiveTLE.fr file description .............................................................C-23
Table C-6. stkActiveTLE.wr file description ...........................................................C-23
Table C-7. Card 1 ................................................................................................C-26
Table C-8. Card 2 ................................................................................................C-27
Table C-9. City database files ...............................................................................C-30
Table C-10. stkCityDb.cd file description..............................................................C-30
Table C-11. stkFacility database files ....................................................................C-32
Table C-12. stkFacility.fd file description...............................................................C-33
Table C-13. stkStarDb database files ....................................................................C-34
Table C-14. stkStarDb.cd file description..............................................................C-35
Table C-15. stkStarDb.bn file description .............................................................C-36
Table D-1. Physical constants ............................................................................... D-2
Table D-2. Astronomical time systems................................................................... D-2
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Table of Contents
Table D-3. Coefficients of drag and solar radiation pressure ................................. D-3
Table D-4. Harris-Priester parameters.................................................................... D-4
Code Listings
Listing B-1. STK Custom Pattern File....................................................................... B-6
Listing B-2. Az-El Mask Format ............................................................................... B-8
Listing B-3. Angle-off-boresight pattern ...............................................................B-10
Listing C-1. Attitude File Format ...........................................................................C-7
Listing C-2. Sample Az-El File Format .....................................................................C-8
Listing C-3. ECITimePosVel File Format ................................................................C-15
Listing C-4. Sample Planetary Ephemeris File Format...........................................C-17
Listing C-5. Sample Torque File Format ...............................................................C-18
Listing C-6. Pixmap File Format ...........................................................................C-19
Listing C-7. Example of owner/mission file for the satellite database....................C-24
Listing C-8. Example of stkActiveTLE.tce file for the satellite database...................C-25
Listing C-9. Example of stkActiveTLE.gd file..........................................................C-26
Listing C-10. TLE File Format ...............................................................................C-28
Listing C-11. Example of country and city type file .............................................C-31
Listing C-12. Example of stkCityDb.gd file...........................................................C-32
Listing C-13. Example of stkFacility.gd file............................................................C-33
Listing C-14. Example of stkFacility.gd file...........................................................C-34
Listing C-15. Example of stkStarDb.bc file ............................................................C-36
Listing C-16. Example of stkStarDb.gd file............................................................C-37
Listing C-17. Sample solar flux data file................................................................C-38
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Satellite Tool Kit® User's Manual
1
INTRODUCTION
Overview
This manual provides instructions and descriptions of the functions available
in Satellite Tool Kit (STK)®, a set of satellite analysis software tools
developed by Analytical Graphics, Inc.
Instructions for installing STK software were shipped separately.
Chapter Contents
Who Should Use This Manual?....................................................................1-2
How This Manual Is Organized....................................................................1-2
Conventions Used in This Manual................................................................1-8
STK Professional Features .............................................................................1-9
Advanced Analysis ..................................................................................1-9
High Precision Orbit Propagator (HPOP) ..............................................1-11
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Introduction
Long-term Orbit Predictor (LOP) ...........................................................1-13
Lifetime .................................................................................................1-14
Terrain...................................................................................................1-14
High Resolution Maps...........................................................................1-15
Additional Resources..................................................................................1-15
Who Should Use This Manual?
This manual is intended for use by both new and experienced satellite
systems analysts. New users of STK may wish to reference the STK Tutorial
to learn about the system in a structured environment. Experienced STK
users can reference the Index and Table of Contents of this manual to locate
specific information and instructions.
This manual assumes that you have a working knowledge of your computer
workstation and operating system. For information about how STK works,
refer to Chapters 2 and 3 of this manual or review the tutorial.
How This Manual Is Organized
This manual is organized into 18 chapters and a number of Appendices that
provide additional information.
1-2
®
Satellite Tool Kit User’s Manual
Introduction
Chapter 1: Introduction
Chapter 1 includes a summary of each chapter and provides a list of
additional resources that may be of help.
Chapter 2: User Interface
Chapter 2 includes an overview of the STK user interface. It provides
instructions for completing basic functions in STK such as creating and
manipulating objects in a scenario, defining the printer setup, defining
the properties of an object and making choices in STK.
Chapter 3: The Map Window
Chapter 3 provides an explanation of the Map window in STK,
including Map properties, animating a scenario and other options that
affect the graphical display of the scenario.
Chapter 4: The STK Application
Chapter 4 provides instructions for defining basic properties at the
application level and for setting IPC and online preferences.
Chapter 5: Scenarios
Chapter 5 explains the concept of the scenario as both an object and a
collection point for all other objects. It also provides instructions for
setting the basic and graphic properties of the scenario.
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Introduction
Chapter 6: Satellites
Chapter 6 is the first of three chapters devoted to different types of
vehicles available in STK. It includes instructions for creating and
defining satellites. The chapter also provides instructions for setting
the satellite’s basic and graphic properties as well as setting satellite
constraints.
Chapter 7: Aircraft, Ground Vehicles & Ships
Chapter 7 is the second of three chapters devoted to different types of
vehicles available in STK. It includes instructions for creating and
defining aircraft, ground vehicles and ships using the great arc
propagator or an external file.
Chapter 8: Launch Vehicles & Missiles
Chapter 8 the last of three chapters that addresses vehicles in STK. It
provides instructions for creating and maintaining launch vehicles
using the simple ascent propagator or missiles using the ballistic
propagator. The chapter also discusses the graphics properties available
for launch vehicles and missiles.
Chapter 9: Facilities and Targets
Chapter 9 provides instructions for setting the basic and graphic
properties of facilities and targets, including position, azimuthelevation mask and attributes. Constraints that can be imposed on
facilities and targets are also reviewed.
1-4
®
Satellite Tool Kit User’s Manual
Introduction
Chapter 10: Area Targets
Chapter 10 provides a description of an area target, and includes
instructions for setting the basic and graphic properties of an area
target. It addresses the centroid position and boundaries of an area
target as well as its attributes in the Map window and the constraints
that can be placed upon it.
Chapter 11: Stars and Planets
Chapter 11 provides instructions for using and defining stars and
planets in a scenario, including basic and graphic properties.
Chapter 12: Sensors
Chapter 12 includes instructions for defining and pointing a sensor as
well as defining the sensor’s resolution. The sensor’s attributes in the
Map window and the special constraints that can be placed on a sensor
are also discussed.
Chapter 13: Using STK Tools
Chapter 13 is the first of four chapters that address the various tools
available in STK. Specific topics of discussion include calculating
accesses, generating vehicle and sensor swath, creating a Walker
constellation, and removing accesses.
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Introduction
Chapter 14: City, Facility, Satellite & Star Databases
Chapter 14 is the second of four chapters devoted to the tools available
in STK. It provides instructions for using the four database tools in
STK. These tools are useful in quickly searching for and inserting
objects into STK.
Chapter 15: Reports & Graphs
Chapter 15 is the third of four chapters devoted to the tools available
in STK. It provides a detailed summary of the reporting and graphing
features available in STK. In addition, it provides instructions for
modifying existing report and graph styles and creating new ones.
Chapter 16: Dynamic Displays & Strip Charts
Chapter 16 is the last of four chapters devoted to the tools available in
STK. It provides a detailed summary of the dynamic display and strip
chart features available in STK. In addition, it provides instructions for
modifying existing dynamic display and strip charts and creating new
ones.
Chapter 17: Using Help
Chapter 17 provides an overview of the STK Help menu as well as
instructions for displaying full text manuals in Adobe Acrobat Reader
and updating data files online. It also provides instructions for using
the Licenses window in STK.
1-6
®
Satellite Tool Kit User’s Manual
Introduction
Chapter 18: Chains Module
Chapter 18 contains information about the Chains module, including
the Chain and Constellation objects, reports unique to Chains, and
more.
Appendix A: Glossary of Terms
Appendix A provides definitions for terms commonly used in STK.
Appendix B: Defining Custom Sensor Patterns
Appendix B explains how to define and create custom sensor patterns.
Several diagrams and examples are provided.
Appendix C: Importing Files
Appendix C provides examples of file formats in case you wish to add
or create files for use in STK.
Appendix D: HPOP Technical Notes
Appendix D provides additional information about the High-Precision
Orbit Propagator (HPOP) module, including equations and models
used.
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Introduction
Appendix E: High-Resolution Map Technical Notes
Appendix E provides technical information about the High-Resolution
Map module, including rank data and pertinent comments.
Conventions Used in This Manual
Certain typographic and formatting conventions have been followed in this
user’s manual to help you quickly and visually understand various kinds of
information:
1-8
♦
Keyboard keys are displayed as graphical representations of the keys. For
instance, R represents the Enter key on a conventional keyboard.
♦
User commands that must be typed are shown in a typewriter font. For
example, # tar xvf /dev/rst0 is one of the commands used when
installing the STK product.
♦
Mouse conventions, such as click, double click and drag, are used often in
this manual. Click means to press and release a mouse button. Double
click means to press and release a mouse button twice in rapid succession.
Click and drag means to press and hold a mouse button while moving the
mouse, then release the button once you stop moving to define an area on
the screen. Unless otherwise noted, use the left mouse button to perform
actions.
♦
Window/screen buttons are displayed in a sans serif font or a picture of
the button is displayed. For instance, the manual may refer to the OK
.
button or just display the button as
♦
Window titles are displayed in a bold italic sans serif font, while tabs within
a window are displayed in bold sans serif and fields in plain sans serif. For
example, the Map Background tab of the Graphic Properties window
contains the Background Image File field.
®
Satellite Tool Kit User’s Manual
Introduction
♦
Notes to the reader are located in a shadowed box. Information contained
in these notes is important and should be taken into consideration. Notes
are identified by the heading
and a icon in the outside margin.
1RWH
♦
Hints to the reader are located in a shadowed box. Hints may contain
shortcuts or helpful information to make your work easier. They are
identified by the heading
and a icon in the outside margin.
+LQW
♦
Warnings to the reader are located in a shadowed box. Warnings contain
important information for the user that may cause problems if not
icon in
followed. They are identified by the heading :DUQLQJ and a
the outside margin.
STK Professional Features
Some of the features and functions described in this manual are available only
with the STK PRO software suite or with individual add-on modules that
address your requirements. Because these functions are embedded in the
STK application, they are presented in this manual. However, they can be
identified by the STK logo (
) in the outside margin. The modules
available as part of the PRO suite or as individual add-on modules are:
Advanced Analysis
The Advanced Analysis module (AAM) provides a package of advanced
features and tools that dramatically extend the capability of STK. This
module is designed to meet the requirements of satellite systems engineers
performing a wide variety of specialized analysis tasks. Specifically, these
features offer advanced functionality in five areas: attitude simulation and
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Satellite Tool Kit User’s Manual
1-9
PRO/
Advanced
Analysis
Introduction
targeting, sensor definition and
visualization, and data management.
constraints,
astrodynamics,
data
Attitude Simulation & Targeting
Attitude simulation and targeting features allow users to define a vehicle’s
attitude by: (1) using one of fifteen pre-defined pointing profiles, (2)
numerically integrating the torques operating on the vehicle’s physical mass
matrix, or (3) defining its orientation relative to a specified target. This
attitude data is typically used with sensor information to resolve complex
geometries when computing ground site visibility and link accesses.
Sensor Definition and Constraints
Sensor definition features allow characterization of alternative sensor types
and parameters. This includes targeting gimbaled sensors, customization of
non-conical sensor patterns, and characterization of specific parameters for
optical sensors. Sensor constraint features support a diverse and sophisticated
set of parameters characterizing sensor access limitations.
Astrodynamics
Astrodynamics features enable use of specialized alternative orbit element
sets and coordinate systems each offering unique analysis advantages.
1-10
®
Satellite Tool Kit User’s Manual
Introduction
Data Visualization
Data visualization features exploit the special advantages of eight alternative
map projections for visualization of ground based information. Additionally,
area targets are provided as STK objects and visualization of vehicle and
sensor swaths is supported.
Data Management
Data management features include three data input/output (I/O)
convenience functions. Custom reports allow users to specify precisely those
output parameters important to their analyses. This allows more concise
reports containing only the data of interest. Batch processing options allow
users to predefine a series of mission scenarios exercising the important
parameter space for a given problem. These are then automatically processed
sequentially in the background storing the results in data files for later
evaluation. Lastly, databases of facilities, cities, and stars are provided.
High Precision Orbit Propagator
(HPOP)
A state-of-the-art orbit generator that can generate orbits for a wide variety
of Earth satellites. It can handle circular, elliptical, parabolic and hyperbolic
orbits at distances ranging from the surface of the Earth to the orbit of the
Moon and beyond.
The HPOP includes modern, high-fidelity models for all of the major
perturbations affecting an Earth satellite:
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Satellite Tool Kit User’s Manual
1-11
PRO/
HPOP
Introduction
♦
Joint Gravity Model (JGM) 2, an advanced 70x70 spherical harmonic
expansion offering the highest accuracy currently available in an
unclassified Earth potential model.
♦
Lunar/solar point-mass gravitational effects, using the U.S. Naval
Observatory Compressed Ephemeris to predict the positions of the Sun
and Moon. This ephemeris is accurate to within 0.03 arc second.
♦
Atmospheric drag, using the Harris Priester atmosphere model, modified
to take into account the diurnal bulge and the variation in the Sun’s
extreme ultraviolet flux, to compute the atmosphere density. The drag
model assumes single-collision specular reflection, which is appropriate for
most satellites. Departures from this can be modeled by changing the areato-mass ratio of the satellite.
♦
Solar radiation pressure, which assumes that the satellite is either a mirror
sphere or a black body. Solar radiation pressure is the same for mirror
spheres and black bodies with the same cross-sectional area, so that users
need not specify the characteristics of the satellite.
The HPOP also takes into account all of the major predictable motions of
the Earth that affect the apparent position of the satellite:
♦
Precession of the equinoxes
♦
Nutation
♦
Diurnal rotation
♦
Barycentric displacement
In addition, the HPOP accounts for the differences among the three primary
astronomical time systems:
1-12
♦
Universal Time Coordinated (UTC), also known as Greenwich Mean
Time (GMT)
♦
International Atomic Time (TAI)
♦
Terrestrial Dynamic Time (TDT), formerly known as Ephemeris Time
(ET)
®
Satellite Tool Kit User’s Manual
Introduction
All input and output are expressed in terms of UTC; TAI and TDT are used
internally to achieve increased accuracy.
For ultra-high-precision, the HPOP uses the Runge-Kutta-Fehlberg method
of order 7-8 to integrate the equations of motion.
Long-term Orbit Predictor (LOP)
PRO/
LOP
The Long-term Orbit Predictor module (LOP) allows accurate prediction of
a satellite’s orbit over many months or years. This is often used for long
duration mission design, fuel budget definition, and end-of-life studies. For
performance reasons, it is impractical to compute the long-term variation in a
satellite’s orbit using high accuracy, small time step, propagators that
compute a satellite’s position as it moves through its orbit. LOP exploits a
“variation of parameters” approach which integrates analytically derived
equations of motion computing the average effects of perturbations over an
orbit. This approach allows large multi-orbit time steps and typically
improves computational speed by several hundred times while still offering
high fidelity computation of orbit parameters.
User inputs include an initial orbit and satellite mass, area, and drag
coefficient. The program implements the 1976 standard atmosphere to
compute the drag effects. Additionally, LOP considers the effects of the
Earth’s oblateness (through J21), the resonant effects of tesseral harmonics,
solar and lunar gravity, and solar radiation pressure when computing the
orbital perturbations. The module is based on algorithms provided by
NASA’s Jet Propulsion Laboratory.
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Introduction
Lifetime
PRO/
Lifetime
Lifetime estimates the amount of time a low Earth orbiting satellite can be
expected to remain in orbit before the drag of the atmosphere causes reentry.
While the computational algorithms are similar to those implemented in the
Long-term Orbit Predictor, there are some important differences. First, a
much more accurate atmospheric model is implemented to compute the drag
effects. The gravitational model for the Earth, however, is significantly
simplified since the inclusion of the higher order terms doesn’t impact orbit
decay estimates. This allows significant performance advantages and provides
a quicker turn around for the analyst.
User inputs include an initial orbit and satellite mass, area, and drag
coefficient. The program implements the Jacchia 1971 atmospheric model to
compute the drag effects. Additionally, Lifetime considers the effects of the
Earth’s oblateness (through J5), solar and lunar gravity, and solar radiation
pressure when computing the orbital perturbations. The module is based on
algorithms developed at NASA’s Langley Research Center.
Terrain
PRO/
Terrain
The Terrain module provides precise three-dimensional (3-D) terrain
elevation data for the entire globe. When used with STK, Terrain exploits
sophisticated multi-dimensional interpolation algorithms to provide accurate
360° azimuth/elevation masks for satellite access calculations from any point
on the Earth’s surface. These algorithms also provide altitude information for
user defined facilities and ground based targets. For users of the VO module,
Terrain allows a vivid 3-D visual depiction of the Earth’s true surface relief
and its effect on satellite accesses.
1-14
®
Satellite Tool Kit User’s Manual
Introduction
The data has a resolution of less than 30 arc-seconds or approximately 1
kilometer at the Earth’s surface. In its compressed format, the complete data
set requires over 400 MB of storage. However, the data can be read directly
from the CD-ROM without loading it onto your hard disk. This data was
originally compiled by the U. S. Geologic Survey from a variety of sources
around the world. It has been processed and formatted for optimal
performance with STK.
High Resolution Maps
This module contains comprehensive, very-high-resolution mapping data for
the entire globe. The data includes coastlines, rivers, lakes and political
boundaries at approximately 1 arc second or 30 meter resolution. This is ideal
for visualizing ground tracks and coverage areas over small geographic
regions. Special data access algorithms have been incorporated to support
rapid visualization of localized map data. The data was extracted from the
1995 CIA RWDB2 database and requires almost 200 MB of storage. It is
formatted for optimal performance with STK.
Additional Resources
You’ll find the following resources to be helpful in developing and furthering
your expertise in using STK.
Astronautics Primer
The Astronautics Primer, by Jerry Jon Sellers, provides a solid
introduction to space. It includes an historical perspective, a lively
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Hi-Res
Hi-Res
Maps
Introduction
introduction to basic astro concepts with easy-to-understand examples,
and discussions of concepts such as access from satellites to ground
stations and other objects. The Astronautics Primer is available in PDF
format and also in Help format.
STK Quick Start
STK’s Quick Start Guide is designed to get you up and running in
minutes. It includes installation instructions, a warp speed start tutorial
and a quick reference for basic functions in STK. The quick start is
available via the Help menu in STK and on the CD-ROM.
STK Help Files
During an STK session, you can find answers to your questions using
STK’s comprehensive Help system. This easy-to-use system contains
information about the features and functions in STK—you don’t have
to leave the software to find your answers.
STK User’s Manual
STK User’s Manu
nuaal provides detailed information and instruction for
performing tasks using STK’s features and functions. STK User’s
Manual is available in hard copy and PDF format.
STK Professional Tutorial
STK Profess
ssiional Tutorial provides a hands-on overview of STK
features and functions. It is the natural follow-up for learning the
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basics of STK. The tutorial sections each require approximately 1 hour
of your time to complete. STK Profess
ssiional Tutorial is available in
hard copy and PDF format.
STK Frequently Asked Questions
STK FAQs provides answers to over 200 frequently asked questions.
Search Analytical Graphic, Inc.’s database for the information you
need. STK FAQs are available via our Web site at www.stk.com.
STK Release Notes
STK Release Notes, which may have been shipped with this document,
clarify known limitations or provide additional details not fully
explained in the current release of the STK User’s Manu
nuaal. STK
Release Notes are available in hard copy and PDF format.
Internet Sources
For up-to-date answers and information about AGI and its products,
visit our web site at www
www..stk.com. For general information about AGI
and our products, send e-mail to [email protected] You can also request
on-line help at supp
ppo
[email protected], and download notes, models and
other useful information at ftp.stk.com.
AGI’s In-View
AGI’s In-View newsletter includes answers to frequently-asked
questions and provides tips on how to perform various analyses. The
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Introduction
newsletter is published three times a year. You can also send e-mail for
the In-View newsletter to [email protected]
Other STK Modules
User manuals for several STK add-on modules are available
separately; they contain detailed instructions and short tutorials.
Manuals are available for:
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◊
Comm™
◊
Coverage™
◊
Interprocess Communications (IPC)™ modules
◊
Precision Orbit Determination System (PODS)™
◊
Generic Resource, Events & Activity Scheduler (GREAS)®
◊
Missile Flight Tool™ (MFT)
◊
Navigator™
◊
and more
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USER INTERFACE
Overview
New users and experienced satellite systems analysts will find that STK’s user
interface makes it easy to perform simple and complicated analysis tasks. The
definitions and descriptions in this chapter will assist in your understanding
of the relationships among STK components, and will guide you through
STK. This chapter also describes one of the two primary windows in STK:
the Browser window. The Browser allows you to easily create, define and
modify objects.
Chapter Contents
Starting & Quitting STK.................................................................................2-3
The Browser Window..................................................................................2-3
Object Menu ..........................................................................................2-5
Opening & Closing a Scenario.....................................................................2-5
Creating a New Object................................................................................2-6
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Inserting an Existing Object into a Scenario .................................................2-6
Last Loaded Function .............................................................................2-8
Linking an Object into a Scenario...........................................................2-8
Saving an Object..........................................................................................2-8
Saving to a Different Directory ................................................................2-9
Saving a Modified Object......................................................................2-10
Saving the Scenario without Children...................................................2-10
Removing an Object from a Scenario........................................................2-10
Setting Up the Printer.................................................................................2-11
2D Map ................................................................................................2-11
Reports & Graphs..................................................................................2-13
Selecting a File............................................................................................2-14
Editing in STK .............................................................................................2-15
Opening an STK Module or External Application.......................................2-15
Defining the Properties of an Object..........................................................2-15
The Property Windows.........................................................................2-16
Describing an Object in STK..................................................................2-17
Using Multiple Windows............................................................................2-17
Using STK Tools..........................................................................................2-17
Using Help .................................................................................................2-18
Making Choices in STK ...............................................................................2-18
Selecting Multiple Objects.....................................................................2-18
Toggle Buttons .....................................................................................2-19
Option Menus ......................................................................................2-20
Radio Buttons .......................................................................................2-20
Lists .......................................................................................................2-20
Using Accelerator Keys...............................................................................2-21
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Starting & Quitting STK
The very first time you run STK, your .cshrc or .profile file is modified to
include the path to STK. To start an STK session for the first time, type:
% <Install Dir>/STKv3/bin/stk R
After the first time, you only need to type stk and press R at the user prompt
to begin an STK session.
STK features a Start Up Wizard that helps you quickly and easily create or load a
scenario. You can set the Wizard to display at start up for every session or you can
disable the feature.
To quit the current STK session, select Exit from the Files menu. When the Confirm
window appears, click OK to exit or Cancel to return to the current STK session.
The Browser Window
The Browser window displays the instances of all classes within a scenario.
Each class of object is associated with a particular icon for easy identification;
the objects appear in the Browser window in a hierarchical form. At the top
level is the application, followed by the scenario and the objects contained in
) appears to the left of
that scenario. An open or closed folder icon (
some objects, indicating that you can collapse or expand the object tree of
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the item selected to hide or view subobjects. In the lower portion of the
Browser window is a group of icons representing each of the object classes in
STK. To create a new object for your scenario, click on the correct icon in
this portion of the window, then name the new object in the top portion of
the window.
The Browser window enables you to manipulate the objects being displayed.
An object is selected when its name is highlighted. At the top of the Browser
window are five pull-down menus: Files, Properties, Edit, Tools, Windows
and Help. Options available in the menu bar are discussed in the following
sections of this chapter and in individual chapters as they pertain to an object.
The Help function is available in the Browser window and as a button in
individual Property windows. If an option can’t be performed for the selected
object, that option appears in light gray type in the pull-down menu and is
said to be “grayed out.”
Figure 2-1. Typical Browser window.
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Object Menu
Following is a list of STK icons representing the various objects in
STK. The icons appear as buttons in the lower portion of the Browser
window and as floating icons elsewhere in STK. If you have an add-on
module to STK, such as Chains or Comm, additional icons may be
serr’s Ma
Manual and Comm Use
serr’s
present. Please consult the Chains Use
Manual for information regarding the use of these icons.
Scenario
Launch Vehicle
Aircraft
Facility
Missile
Planet
Target
Ship
Star
Area
Target
Ground Vehicle
Sensor
Satellite
Opening & Closing a Scenario
To open a previously saved scenario, including all of its objects and
properties, select Open from the Files menu. Choose the scenario you wish
to open.
STK is ready to use when text and data appear in the Browser window and
the Map window appears.
The speed and power of your workstation combined with the complexity of your scenario
determines how long it takes to open the scenario.
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To close a scenario without exiting STK, highlight the scenario in the
Browser window, select Close from the Files menu. The Browser window
updates to show only the application; the Map window(s) disappears. You
can now open a different scenario or create a new one.
To learn more about the Map window, please refer to Chapter 3 of this manual.
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Creating a New Object
To create a new object for the current scenario, highlight the scenario in the
Browser window and click on the appropriate icon (refer to page 2-5 for
more information) in the lower portion of the window. When the Browser
window displays the new object’s name, click on the highlighted text, type
the object’s new name, and press R. The object’s name can only consist
of alphanumeric characters separated by an underscore ( _ ) and/or dash (-);
it cannot include other punctuation marks such as commas (,), spaces or
slashes (/).
You can also use the New function available from the Files menu. Just select
New, then select the type of object you wish to create in the pull-right menu
that appears.
Inserting an Existing Object into a
Scenario
Any time you create or modify an object in STK, the properties of that
object, including its state and graphical attributes, are retained in a file for
that specific object. When you create another scenario and insert the object
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into the new scenario, all characteristics and attributes of that object are
present and all subobjects (i.e., sensors) are also inserted as well.
To insert an object that was previously defined and saved, highlight the
scenario in the Browser window, select Insert… from the Files menu. An
Insert window appears.
Figure 2-2. Typical Insert window.
Click on the File Type option menu at the top of the window and highlight
the class of object you’re searching for in the menu that appears. Check the
Filter and Selection text boxes to ensure that they are pointing to the directory
where the file is located. If the Selection text box isn’t pointing to the correct
directory, highlight the path in the Directories list or enter the correct path in
the Filter text box and click on the Filter button at the bottom of the window
or press R.
When the correct directory displays, highlight the object in the Files list that
you wish to insert into the current scenario and click on OK.
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The Browser and Map windows are updated to include the previously defined
object.
Last Loaded Function
STK allows you to recall the last six objects opened or inserted into the
current STK session. The Last Loaded function, available through the Files
menu in the Browser, features a pull-right menu that lists the last six objects
opened (i.e., scenarios) or inserted into a scenario (i.e., vehicles, facilities,
targets, area targets, planets, stars, sensors).
Linking an Object into a Scenario
You can also insert a link to an existing object. To do this, highlight the
scenario in the Browser window, select Insert As Link… from the Files menu.
Choose the object to which you wish to insert a link and click OK in the
Insert window. The object appears in the Browser window. However, object
attributes and properties can't be changed.
Saving an Object
To save a newly created object, highlight the object in the Browser window,
select Save from the Files menu.
STK saves data in a hierarchical form, meaning that when you save an object,
all subordinate objects are saved as well, unless you choose the Save (No
Children) option. Thus, when you save a scenario, all objects within that
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scenario are saved to a file as well. In the same manner, when you save a
vehicle, facility or target, any sensors attached to that object are also saved. In
addition, relationships among objects are preserved. If you insert a vehicle,
any sensors attached to that vehicle are also inserted into the scenario. The
names of any subobjects owned by the object are saved in the object file.
If you save an object using a file name that already exists, the existing file is overwritten
and previous contents are lost.
:DUQLQJ
When you change an object during an STK session, none
of the changes are saved to the object’s file until
you save either the object itself or save the parent
of the object. For example, you can attach the same sensor to multiple
vehicles within a given scenario and make changes to individual sensors
attached to the different vehicles within the scenario so that they appear
independently during animation. If you save the entire scenario, the
properties of the last sensor saved define and overwrite the properties of any
like-named versions of that sensor.
You can also save the object by pressing the A + S keys. For more information about
accelerator keys, refer to page 2-21.
Saving to a Different Directory
The STKDb directory specified in your STK run control file serves as the
starting point for any STK session. Any time you select Open, Insert… or Save
As… from the Files menu, the default directory appears in the Selection and
Filter paths. If you choose a different directory, your choice remains in effect
until you change directories via Open, Insert… or Save As… again.
If you wish to save an object to a directory other than the current directory,
highlight the object in the Browser window, select Save As… from the Files
menu.
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Saving a Modified Object
If you modify a previously saved object and you wish to save it under the
same name, the modifications apply to all instances of
that object in all scenarios. Consider the impact to other users
who may need the original object. To avoid potential problems with other
scenarios, use the Save As… function.
Saving the Scenario without
Children
If you select this option for Save or Save As…, only the selected object itself
is saved. Thus, you can save a scenario without saving any of its subobjects,
or you can save a vehicle or facility without saving its attached sensors.
Removing an Object from a Scenario
You can remove an object from a scenario by highlighting the object in the
Browser window and selecting Remove from the Files menu. The object is no
longer a part of your scenario. If you saved the object previously, it’s
available for you to import into other scenarios or even this one if you
change your mind. If you didn’t save the object and it was newly created, the
object won’t be available for other scenarios. To delete an object from STK,
you must be outside of STK and use commands native to your operating
system.
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Setting Up the Printer
To set up your print parameters, select Print Setup from the Files menu. A
Print Setup window appears, containing two tabs: 2D Map and Reports &
Graphs.
2D Map
The options in the 2D Map tab control the way in which the Map window
prints, including page layout, attributes and output device.
The fields available in the 2D Map tab are discussed in the table following.
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Table 2-1. 2D Map print options
Option
Description
Page Layout
The options in this section allow you to specify how you wish the
Map window to print. Choices are:
Attributes
Output Device
♦
Orientation - Choose between Landscape or Portrait.
♦
Layout - Choose between Rectangular or Square. The
Square layout is best for Orthographic, Stereographic,
Azimuthal Equidistant, and Perspective projections.
♦
Width/Height - Specify the Width and Height of the
paper to be used (e.g., 8 ½ x 11 or 11x14).
The options in this section allow you to specify the color and
format to be used when printing the Map window. Choices are:
♦
Color Mode - Choose between Gray (black and white) or
Color printing.
♦
Background - Choose to print White on black images
(ideal for presentations) or Black on white (typically used
for printing hard copies).
♦
File Format - Choose to print using PostScript (PS),
encapsulated PostScript (EPS) or Hewlett Packard
Graphic Language (HPGL) commands.
The choices in this section allow you to choose the printer or
directory to which the Map window prints. Select either:
♦
Printer - Choose the printer on which you wish to print
the Map window. The default printer is the printer
specified in your STK run control file.
♦
File - Choose this option to print the Map to a file in the
format you chose in the File Format field. Use the
button to browse through a list of files and specify the
directory path and name for the file.
Printer Command
2-12
Specify the correct print command specific to the platform for
Graphic files in the text box.
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Reports & Graphs
The options in the Reports & Graphs tab control the way in which all reports
and graphs generated during the STK session print, including page layout,
attributes and output device.
Additional options for printing reports and graphs are:
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Table 2-2. Additional print options for reports & graphs
Option
Description
Page Layout
The options in this section allow you to specify how you wish
reports and graphs to print. Choices are:
Attributes
♦
Lines Per Page - Specify the maximum number of lines to
be printed on a single page.
♦
Wrap Lines - Specify whether lines of text should wrap to
the next line.
♦
Margins - Specify the Top, Bottom, Left and Right
margins to be used when printing a report. Default
margins are 0.25 inches.
The options in this section allow you to specify the format of
reports and graphs when printing. Choices are:
♦
+LQW
Font Style - Choose the font to be used to print text for
reports and graphs. Available fonts can be found in the
STK run control file.
The Lines per Page field is based on a nonproportional font, such as Helvetica. For reports,
it is best to use a nonproportional font, such as Helvetica 10 point, so that the printed
report looks professional. For graphs, you can choose a larger font.
Selecting a File
Sometimes you may wish to import an object file or data into your scenario.
Click on the
button in the current window to browse through a list of
available files. A Select File window appears.
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For information about importing specific types of files in STK< please refer to Appendix B
of this manual.
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Editing in STK
STK now features traditional Copy, Cut and Paste options so that you can
easily use data in more than one place. These features are available through
the Edit menu in the Browser for vehicles, facilities, targets, area targets,
planets, stars and sensors.
Opening an STK Module or External
Application
STK includes a large family of products that are integrated with the STK
application. Some functions are seamlessly integrated into STK, such as
Comm, IPC and Chains. Other applications, developed by companies
working in partnership with Analytical Graphics, are integrated into STK
through the External Apps option in the Files menu. If you have licenses for
applications such as Missile Flight Tool (MFT), GREAS or other
applications, use the External Apps option to display a pull-right menu listing
available applications.
Defining the Properties of an Object
You can define an object’s basic and graphics properties as well as constraints
for the object by selecting an option in the Properties menu. Properties for
each object are discussed in subsequent chapters of this manual. Please refer
to the specific object for instructions on setting object properties.
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Options are “grayed out” or unavailable if they appear in light gray print.
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Basic
Use this option to specify and display the general characteristics
of an object (such as time period or type of path). Basic
properties are used to define all objects, including the STK
application; however, the tabs within the Basic Properties
window vary according to the object highlighted.
Graphics
Use this option to specify and display the graphics
characteristics of an object (such as color). Graphics properties
are used to define all objects; however, the tabs within the
Graphics Properties window vary according to the object
highlighted. This option isn't available if the STK application is
selected.
Constraint
Use this option to specify and display the constraints of an
object. This option isn't available if the STK application, a
scenario, or a star or planet class is selected.
The Property Windows
Property windows are divided into tabs and are used to display and specify
the properties of objects. Using the Property windows, you can display the
status of particular conditions and enter specifications. All Property windows
can be resized as needed to accommodate the data being displayed. Any
number of Property windows can be open at one time.
All Property windows contain four control buttons, described below.
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♦
Applies settings and closes window.
♦
Applies settings but leaves window open.
♦
Closes window without applying settings.
♦
Displays an on-line help window.
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Describing an Object in STK
When you create a scenario, or any other object, you may want to record
ancillary information for future reference. The
Description tab of the
Basic Properties window allows you to create a short and/or long description
of the object to be saved with the object.
The Short Description field is limited to one line of text and the Long
Description field is limited to 511 characters, including spaces and
punctuation. The Description tab exists as a basic property of the scenario and
all objects that can be contained in a scenario.
Using Multiple Windows
To better control and organize the various tasks you perform in STK, the
Windows menu lists each of the windows, whether Map or property, that are
open during an STK session. You can select the window of interest to bring it
to the front. This is especially useful if the scenario includes multiple Map
windows and you have a number of object property windows open. In
addition, you can toggle between allowing only one instance of the same
window to be open at any one given time or allowing multiple copies of the
same window to be open simultaneously.
Using STK Tools
You can use specialized STK tools to perform analyses tasks and assist you in
defining and displaying accesses, lighting conditions, vehicle swaths and
Walker constellations. Tools are also available for creating standard and
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customized reports, viewing report data in graph form to better analyze data,
easily importing known satellites with user-friendly search parameters,
removing accesses and restoring the Map window. STK tools are discussed in
detail in Chapters 13 through 16 of this manual.
Using Help
STK features detailed Help that can assist you in completing tasks by
displaying on-line instructions. You can display general Help in the Browser
window or task-specific Help in individual Property windows. An overview
of the Help system is provided in Chapter 17 of this manual.
Making Choices in STK
Another fundamental concept in STK involves toggle buttons, option menus,
lists and radio buttons that provide you with a choice of options.
Selecting Multiple Objects
You can select multiple objects in the Browser window by pressing and
holding the S to select tangent objects or C to select miscellaneous
objects. Once you’ve selected multiple objects in the Browser, you can use
the Report and Graph tools to collectively display information about the
objects.
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Toggle Buttons
Toggle buttons are those which flip between two opposite conditions. Toggle
buttons appear raised when they are not selected. If you click on them, they
appear pushed in or depressed (indicating that they are selected). For
example, on the Pass tab of the Graphics Properties window for a vehicle, you
(such as Orbit Lead Type) to turn the lead
can click on a toggle button
orbit tracks ON or OFF in the Map window. The picture following shows
several toggle buttons. In UNIX, toggle buttons are typically square.
Figure 2-3. Satellite Pass tab illustrating toggle buttons, radio buttons and
option menus.
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Option Menus
Option menus, shown in the Graphics Properties window, allow you to select
one and only one item from a list that appears when you click and hold the
associated option menu button. To select an item other than the one
currently displayed on the face of the option menu, click on the option menu
and use the mouse to highlight the item of interest in the list that
appears, then release the mouse. Option menus can be identified by small
rectangles on the right side of the button, or a down-pointing arrow to the
right of the field’s name.
Radio Buttons
Radio buttons
occur in a group. You can select one and only one item in
the group of radio buttons (similar to the way the radio buttons work in your
car). For example, the Pass tab of the Graphics Properties window features
radio buttons that allow you to choose between displaying all pass data in the
Map window or displaying a specified range of pass data. In Motif, radio
buttons are typically diamond shaped.
Lists
Lists, such as the Items list shown in the Map Details tab, allow you to select
multiple items in a scrollable area. The Map Details tab allows you to choose
which map features you wish to see displayed in the Map window. To select
an item, click on the item within the scrollable field so that it is highlighted.
To remove an item from the list, click on the highlighted item again.
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Using Accelerator Keys
Keyboard accelerators, shown on pull-down menus and submenus, speed up
your access to an action. Many of the tasks you perform in STK on a
frequent or repeating basis can be invoked using keyboard accelerators.
Options available in and through the menu bar have associated keyboard
accelerators if an underlined letter appears in the option’s name (for example,
Close or Insert…) or a key combination appears to the right of the option’s
name in a pull-down menu. The key that serves as the Meta key differs from
one machine to another but typically has a unique shape (such as the
diamond on the Sun workstation Meta key) or a unique word (A function
on the DEC and IBM workstation Meta keys).
You can’t use Meta Keys if n or c is ON.
If you use the Remove command to remove an object from the current scenario without
saving the object, the object won’t be available for other scenarios.
Table 2-3. Accelerator keys
Key
combination
Function
Meta + A
Displays Access window for selected object.
Meta + B
Displays Basic Properties window for selected object.
Meta + C
Copies selected text.
Meta + D
Sets the current properties for the selected object as the
default for all future objects created in that class.
Meta + E
Displays Edit pull-down menu.
Meta + F
Displays Files pull-down menu.
Meta + G
Displays Graphics Properties window for selected object.
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2-22
Key
combination
Function
Meta + H
Displays Help pull-down menu.
Meta + I
Inserts existing object into the current scenario.
Meta + J
Saves the select object or scenario but doesn't save any
subobjects attached to the object being saved.
Meta + l
Inserts existing object into the current scenario as a link
only.
Meta + N
Displays Constraints Properties window for selected
object.
Meta + O
Opens previously saved scenario.
Meta + P
Displays Properties pull-down menu.
Meta + R
Removes object from the current scenario.
Meta + S
Saves selected object or scenario.
Meta + T
Displays Tools pull-down menu.
Meta + V
Pastes text entered into clipboard at the specified location.
Meta + W
Displays the Windows pull-down menu.
Meta + X
Removes the selected text.
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THE MAP
WINDOW
Overview
The Map window graphically displays information about your scenario. Use
the tool bar, located at the top of the Map window, to control animation and
zooming. Use the status bar, located along the bottom of the window, to
check the cursor’s latitude and longitude position, the name of the selected
object, and the current scenario time. You can specify a number of Map
window display options directly from an STK session, including map colors,
geographic features, display format, latitude/longitude line spacing, etc. In
addition, you can open multiple Map windows for a single scenario with
different display options to further your analysis efforts.
Satellite Tool Kit® User's Manual
3-1
The Map Window
Figure 3-1. The Map window.
1RWH
For publication purposes, map colors have been reversed. In most instances, the Map
window is a color-on-black display.
Chapter Contents
The Tool Bar.................................................................................................3-3
Animation Time Steps...................................................................................3-4
Map Properties.............................................................................................3-5
Map Attributes ........................................................................................3-5
Map Details.............................................................................................3-6
Map Projection........................................................................................3-9
Map Background..................................................................................3-14
Text Annotation ....................................................................................3-15
Status Bar ...................................................................................................3-17
Animating a Scenario.................................................................................3-18
Animation and its Relationship to Vehicle Tracks ..................................3-18
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Satellite Tool Kit® User's Manual
The Map Window
The Tool Bar
The tool bar displays at the top of the Map window. It allows the user to
easily control the graphical display of the scenario in the Map window.
The tool bar message box, located on the far right of the tool bar, displays a
text description of any button on the tool bar when you move the cursor
over a button.
Table 3-1 provides an easy reference for tool bar buttons in the Map
window.
Table 3-1. Tool bar buttons
Button
Function
Prints the current Map window (excluding window borders and the
tool bar) to the default printer.
Decreases the time step.
Reverses animation one time step.
Plays the scenario in reverse sequence.
Pauses the animation sequence at the current time.
Stops the animation and reset to the beginning of the animation.
Animates the scenario in forward sequence.
Moves the scenario forward one step.
Increases the time step.
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The Map Window
Button
Function
Zooms in on (magnifies) a portion of the map. Click this button, then
click and hold the left mouse button and drag it over the portion of the
map you wish to magnify. Click this button as many times as needed to
increase magnification of a portion of the map.
Zooms out to view a larger portion of the map. Click this button as
many times as needed to see the “big picture.”
Measures distance between any two points in the map. Click this
button, then click and drag the mouse between the two points on the
map you wish to measure. When you release the mouse button, a
message window appears displaying the distance between the two
points, the central angle and the azimuth bearing.
Resizes map to its correct 2:1 aspect ratio.
Displays a Map Properties window. Refer to page 3-5 for a detailed
discussion about Map graphics properties.
Animation Time Steps
Animation Steps increase or decrease incrementally as follows:
0.01
0.10
0.50
3.00
5.00
10.00
30.00
60.00
180.00
300.00
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Satellite Tool Kit® User's Manual
The Map Window
600.00
1000.00
3600.00
For instance, if you click the
(Increase Time Step) button three times, and
the animation rate was originally set to the default of 60.00 seconds, the new
animation rate is 600.00 seconds.
Map Properties
Use the
button to display the Map Properties window for the Map.
Map Attributes
The fields in the Map Attributes tab allow you to control the display of the
tool and status bars, scroll bars, and terrain data.
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The Map Window
Table 3-2. Map display options
Option
Description
Show Tool Bar
If ON, the tool bar displays at the top of the Map window. The
tool bar controls animation.
Show Scroll Bars
Toggle ON and OFF to control the display of tool bars on the
right hand side and bottom of the Map window.
Show Status Bar
If ON, the status bar displays at the bottom of the map window.
The status bar displays the position of the cursor in the Map
window in latitude/longitude, animation running time and
associated information.
Show Terrain
If ON, terrain regions are clearly marked in the Map window.
You can’t animate a scenario if the tool bar option is turned OFF.
+LQW
Map Details
The Map Details tab allows you to select the type and resolution of details
displayed in the Map window. Typically, these options aren’t used when you
choose a textured Map display. STK is shipped with a number of map details,
including Relational World Data Bank II (RWDBII) maps. RWDBII maps,
originally used by the CIA, are now publicly available maps known for their
accuracy.
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Satellite Tool Kit® User's Manual
The Map Window
Table 3-3. Options for Map details
Option
Description
Items
Select the details you wish to display.
Lat/Lon Lines
IF ON, you can specify the spacing between latitude lines. By
default, spacing between longitude lines is the same as the spacing
between latitude lines. If you wish to change the default, turn the
Lon Lines option ON and enter the spacing desired. Spacing for
both latitude and longitude lines can be set as small as 0.001°.
Background
Select the image you wish to view in the Image field or the
background color of the Map in the Color field.
If you set very small latitude/longitude line spacing in the Map window, performance may
decrease unless only a small portion of the central body is visible in the Map window.
For printing purposes, try printing with a white background color and dark (black, brown,
etc.) lat/lon line colors.
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+LQW
The Map Window
Advanced Details
Use the Advanced… button to fine tune the map display by controlling the
display and color of specific map details.
Select the category of interest, then specify whether the level of detail
selected should be displayed in the Map window. If the Display option is set
to Yes, specify the Color in which the details should be displayed. Details in a
specific category, such as international borders, can be dealt with as a group,
or you can specify the display and color of particular features within the
category, such as demilitarized zone lines and specified claimed lines. To
make the display and color of all map details uniform, use the Select All button.
Hi-Resolution Maps (Module)
PRO/
Hi-Res
Maps
This module contains comprehensive, very-high-resolution mapping data for
the entire globe. The data includes coastlines, rivers, lakes and political boundaries at
approximately 1 arc second or 30 meter resolution. This is ideal for visualizing
ground tracks and coverage areas over small geographic regions. Special data access
algorithms have been incorporated to support rapid visualization of localized map
data. The data was extracted from the 1995 CIA RWDB2 database and requires
almost 200 MB of storage. It is formatted for optimal performance with STK.
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Satellite Tool Kit® User's Manual
The Map Window
If you have the Hi-Res Map module, more detail levels are available as
subcategories of using the Advanced… button. To set the Display and Color of
individual subcategories, you must first set the display of the parent category.
Once the parent category options are set, select the individual subcategories
of interest and change them.
Map Projection
The fields in the Projection tab allow you to set the graphical display of the
world in the Map window.
1
You can select one of the map projections described in the following
subsections to best support your analysis or simulation.
1
John P. Snyder, Map Projections—A Working Manual, United States
Government Printing Office, 1987.
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3-9
The Map Window
Basic Map Projections
The map projections in the table following are available with STK.
Table 3-4. Basic projection types
Projection Type
Description
Equidistant
Cylindrical
Projection is mathematically based on a cone that is tangent at
one parallel or conceptually secant at two parallels. North or
south pole is represented by an arc.
Mercator
Projection can be thought of as being mathematically based on
a cylinder tangent at the equator. Any straight line is a constantazimuth line, which is also called a loxodrome or rhumb line.
The north and south poles can’t be shown in this rectangular
projection since they are at infinite distance.
Perspective
Projection of the central body as a sphere from a user-specified
viewing altitude. If you choose this projection type, specify the
3-D Orbit Type as one of the following:
♦
ECF - Earth-Centered Fixed. The orbit track displays
above the ground track over the entire span of
displayed ephemeris.
♦
ECI - Earth-Centered Inertial. A representation of the
orbit in inertial space (corresponding to the current
animation time) displays.
In the Field of View field, enter an angle value to narrow or
broaden the perspective. In all cases, the observer’s position is
fixed in the ECF reference frame at the Projection Center
Position. If ECI is selected, the orbit plane appears to move in
time as you animate.
The map projection selected is saved when you save the scenario.
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Satellite Tool Kit® User's Manual
The Map Window
Advanced Projections
If you have a license for the STK Advanced Analysis module, the following
additional projections are available:
Table 3-5. Advanced projection types
Projection Type
Description
Azimuthal
Equidistant
Projection is mathematically based on a plane tangent to the
Earth. Spacing of the parallels is uniform.
Miller
Rectangular projection constructed to provide an alternative to
the Mercator projection. The two projections are similar near the
equator but the Miller projection avoids some of the
exaggeration in scale near the poles.
Mollweide
Equal and pseudo-cylindrical projection showing the Earth in an
ellipse with the equator twice as long as the map’s actual
meridian.
Orthographic
Projection is geometrically based on a plane tangent to the Earth.
The point of projection is at infinity. Directions from the center
of the map projection are true.
Sinusoidal
Projection is mathematically based on a cylinder tangent on the
equator. May have several central meridians.
Stereographic
Projection is geometrically projected onto a plane. The point of
projection is on the surface of the sphere opposite the point of
tangency. Directions from the center of the projection are true.
Hammer-Aitoff
Variation of the Lambert Azimuthal Equal Area projection that
allows for viewing at both hemispheres simultaneously. The
equal area characteristic of the Lambert projection is mostly
preserved. This projection is visually similar to the Mollweide
projection.
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3-11
The Map Window
Example Projection Types
Projection types Equidistant Cylindrical and Mercator are shown below.
Projection types Miller and Mollweide:
Projection types Sinusoidal and Orthographic:
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Satellite Tool Kit® User's Manual
The Map Window
Projection types Stereographic and Azimuthal Equidistant:
Projection types Hammer-Aitoff and Perspective:
Center
To set the center point for the map projection selected, enter the exact
latitude and longitude degrees in the respective fields. You can also click at a
location in the Map window to identify the center point. If you click in the
Map window to set Latitude/Longitude coordinates, the new
Latitude/Longitude values display in the fields of the Map Projection tab. This
feature is available even if your map is zoomed. The Latitude field isn’t
available for Equidistant Cylindrical, Mercator, Miller, Mollweide, Sinusoidal or
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3-13
The Map Window
Hammer-Aitoff Projections. The Altitude field is only applicable if you choose a
Perspective Projection.
Map Background
The Background tab allows you to specify the background image to display in the
Map window.
STK ships with several background image files. You can also supply your
own files to display in the Map window if, for instance, you wish to display
your company name and logo as the background for the Map window. The
2
image must be an XPM file for UNIX. Select the image you wish to display
in the Available Images list, then use the right arrow to copy the image to the
Displayed Images list. Once there, you can change the display size and
location of the image using the North and South Lat and East and West Lon
fields.
2
LeHors, Arnaud, XPM Manual version 3.4c, Bull Research 1989-94, May
th
27 , 1994.
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Satellite Tool Kit® User's Manual
The Map Window
To import a background image that currently isn't displayed in the Available
Images list, use the Add… button.
Figure 3-2. Map window with texture background
To return to the default map display, highlight the background image file
entitled “None” and click OK.
Text Annotation
The Text Annotation tab allows you to specify text to display in the Map
window at a specified latitude and longitude and/or at a specific X,Y
coordinate.
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The Map Window
Adding and Deleting a Text
Annotation
To add new text to the Map window, select Add New Item in the Edit Mode
field, then choose a position for the text to appear on the Map. You can also
set the position of the text directly from the Map window by clicking at the
point in the Map window where you wish to place the text.
Table 3-6. Text annotation position options
Option
Description
XY
The 0,0 point for X,Y is the center of the Map; therefore, X values must
be between -180° and +180° and Y values must be between -90° and
+90°. An annotation positioned using X,Y coordinates isn’t affected by
the Map Projection.
Lat/Lon
If you use Lat/Lon to position the text, the text moves with the Map as
you change the Map Projection type and center point.
Enter the text in the large text box. You can also specify a color for the text.
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The Map Window
When everything is set, click Insert Point. The Items list is updated to reflect
your addition and the Map window displays the text where specified.
To delete a previously saved text annotation, highlight the text in the Items
list box and click the Delete Point button.
The Insert Point button becomes a Modify Point button when you switch Edit Modes to
Change Current Item.
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You can also change a previously saved text annotation by using the Change
Current Item option.
Status Bar
At the bottom of the Map window, the status bar (shown below) displays the
current latitude and longitude of your cursor in the Map window, the name
of the object selected, if any, and the current scenario time.
Figure 3-3. Status bar in Map window
To select an object, position your cursor over that object (e.g., a ground
track, a facility, a target, or a sensor) in the Map window and hold down the
left mouse button. The name of the object you’ve selected appears in the
center box of the status area. If the object is a vehicle or vehicle track, a
message window appears displaying the object’s location, pass number,
vehicle crossing time and pass direction (ascending or descending).
You can change the animation time in the status bar by clicking on the time displayed in
the bar and typing over it. You can also type in today, tomorrow, yesterday and now as a
time.
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3-17
+LQW
The Map Window
Animating a Scenario
As you define and analyze a scenario using STK, you can animate the
scenario to more fully understand time-based relationships and interactions.
Because satellite systems are so dynamic, it is important to analyze the
scenario in motion.
For the animation of a scenario to be meaningful, the objects in the scenario
with time dependencies should be properly defined. For example, vehicles
must have ephemeris within the animation period to be affected by the
scenario animation. Animating the scenario displays vehicles moving along
their ground tracks, the intersections of sensors with the central body and
the subobject locations for planet and stars.
1RWH
If you're animating a scenario in the Map window and need to perform other tasks in STK,
you may want to first Pause the animation and then begin other tasks. If you animate
while multitasking, all other processes/ applications are slowed down.
Animation and its Relationship to
Vehicle Tracks
In preparing to animate a scenario in STK, it is important to understand the
relationship between the date/time established for orbital elements and the
date/time established for the animation. You must propagate a path and generate
ephemeris for a vehicle that overlaps all or a portion of the date and time range set
for the scenario animation. If the date and time of animation fall outside the range
of available ephemeris, the vehicle doesn’t move during animation. You must either
propagate ephemeris that use the date and time set for the scenario animation or
you need to change the date and time for your scenario animation so that it falls
within the span of the available ephemeris.
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Satellite Tool Kit® User's Manual
4
STK APPLICATION
Overview
The STK application contains your scenario and all of the objects in the
scenario. When you set properties at the application level, they remain in
effect for all scenarios, whether they are previously saved scenarios opened
during an STK session or newly created scenarios.
Chapter Contents
Basic Properties: STK Save Prefs ....................................................................4-2
Basic Properties: IPC Preferences ..................................................................4-3
Basic Properties: Online Operations.............................................................4-5
Satellite Tool Kit® User’s Manual
4-1
STK Application
Basic Properties: STK Save Prefs
The Save Prefs tab allows you to activate or disable Auto Save, specify the
directory path and time interval for saving your scenario, or perform a Quick
Save of your scenario.
When STK is selected, Basic is the only option available in the Properties menu.
1RWH
The fields available in the Save Prefs tab are discussed in Table 4-1. Save
preferences aren’t saved when you exit STK; you must reset these
options each time you run STK or change the default SavePrefs
keyword in the application's default preferences file.
Table 4-1. Save preferences
4-2
Field
Description
Save Vehicle
Ephemeris
If ON, ephemeris of all vehicles is saved in your scenario
whenever an Auto Save is performed.
Binary Format
If ON, ephemeris is saved in binary format whenever an Auto
Save is performed.
Save Accesses
If ON, accesses computed in the scenario are saved.
Satellite Tool Kit® User’s Manual
STK Application
Field
Description
Quick Save
Immediately saves your current scenario to your default directory
without saving other objects in the scenario.
Auto Save Enabled
If ON, the system automatically saves your work at the interval
specified in the Save Period field.
Directory
Specifies where your STK scenario data is located. Enter the
complete directory path in which you want to store your
scenarios and objects.
Save Period (min)
The interval for which you wish STK to automatically save your
scenario. As shown, the scenario is saved every five minutes.
Basic Properties: IPC Preferences
If you purchased the IPC add-on module, you can set IPC preferences at the
STK application level.
The fields available in this tab are discussed in the table following.
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STK Application
Table 4-2. IPC preferences
Option
Description
Allow Connect
Yes/No. Specifies whether IPC should allow connections.
Allow Async
Yes/No. Specifies whether to allow a connection to be placed
in asynchronous communications mode.
Max Connections
Specifies the maximum number of simultaneous IPC
connections to be accepted by STK.
Poll Period
Specifies the maximum number of connections to interrogate
in a given poll period.
Default Connection
Settings
Specifies the default settings for IPC messages.
Connection Method
4-4
♦
Acknowledge - If ON, IPC sends an
acknowledgment message (ACK) in response to
receipt of an incoming message.
♦
Echo - Specifies whether IPC should echo incoming
messages to the user application. When ON, you can
determine which message IPC is currently
processing.
♦
Verbose - If ON, this parameter allows IPC to
respond with detailed information, via standard
output, about connections and message traffic.
Specifies the type of connection to accept.
♦
UnixSocket connection is restricted for use of the
machine on which STK is running (UNIX operating
system on SUN and SGI only).
♦
TCPSocket connections to be used over the network.
Satellite Tool Kit® User’s Manual
STK Application
Basic Properties: Online Operations
The Online tab sets the online access preferences to be used within STK. It
enables you to download databases, TLE files and other data from AGI’s web
site.
The fields available in this tab are discussed in the table following.
Table 4-3. Online preferences
Option
Description
Allow Online Operations
On/Off. If ON, you can perform automatic updates of
databases during an STK session.
HTTP Proxy
If the Use Proxy option is ON, specify the correct Server
and Port information. Use this option if your internet
access is via a firewall.
Browser Name
Specify the location of the executable to be used to launch
the default Web browser.
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STK Application
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5
SCENARIOS
Overview
This chapter describes the properties of a scenario and how to manipulate
scenarios effectively. A scenario is the object in STK that serves as the
container or collection point for all other objects (vehicles, facilities, targets,
area targets, planets, stars and sensors). This collection of objects becomes
the outline for a proposed or planned configuration that you need to analyze.
You can create and maintain any number of scenarios; the objects you create
to populate various scenarios can be used concurrently in some or all of your
scenarios.
Only one scenario can be open at any given time during the STK session.
The scenario serves as the framework for your analysis. As part of
establishing this framework, you can define an epoch and a time period. The
epoch serves as a reference for all other times in the scenario. The time and
date of the epoch correspond to zero epoch seconds. The time period defines
the general time span (a range of several hours, days or weeks) for analysis. A
redefinition of the time period results in the propagation of the orbits for all
satellites currently loaded in the scenario.
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Scenarios
Chapter Contents
Basic Properties: Setting the Time Period......................................................5-2
Basic Properties: Setting Animation Options.................................................5-4
Basic Properties: Setting Units of Measure....................................................5-7
Entering Units in Text Fields ..................................................................5-11
Basic Properties: Setting Default Databases................................................5-11
Basic Properties: Terrain..............................................................................5-12
Adding Terrain Elevation Data..............................................................5-13
Graphics Properties: Global Attributes........................................................5-14
Graphics Properties: Sun Lighting ..............................................................5-16
Basic Properties: Setting the Time
Period
The Time Period tab allows you to specify the Epoch of your scenario and the
Start/Stop Times of your scenario in established units.
5-2
Satellite Tool Kit® User’s Manual
Scenarios
To ensure that all vehicles have ephemeris in the same time frame, propagate the vehicles
using the scenario’s Time Period tab.
+LQW
If you change the Start and Stop Times in this tab, STK automatically
propagates all vehicles in your scenario over the specified time period.
Formats for all time-related fields are dependent upon the Time Units set at the scenario
level. Refer to page 5-7.
1RWH
The scenario’s Time Period is also used as the default time period for
operations involving objects that don’t have an implicit sense of
availability. A vehicle, for example, has an interval of availability that is
defined by the span of its ephemeris, while a facility has no such timeoriented constraints and uses the scenario time period if such an
interval is needed. Finally, animation Start and Stop times are
automatically updated to match the time period when a new one is set
here.
Changing the scenario Epoch after subobjects have been created or inserted may result in
unpredictable difficulties.
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:DUQLQJ
Scenarios
If you change the Epoch of a scenario, any subsequent or newly defined
vehicles have a default Start Time and Orbit Epoch equal to the new epoch.
In addition, relative start times (in epoch seconds) are adjusted
accordingly for all previously defined objects. For new scenarios, the
default Start Time in the Time Period tab is the scenario Epoch; the Stop
Time defaults to the Start Time plus four hours.
Table 5-1. Time period options
Field
Description
Start
Start time for the scenario period.
Stop
Stop time for the scenario period.
Epoch
Date and time in established units to represent zero epoch seconds of
the scenario.
Basic Properties: Setting Animation
Options
The options in the Animation tab allow you to set the Start/Stop/Epoch and
Time Step for the scenario.
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Scenarios
Formats for all time-related fields are dependent upon the Time Units set at the scenario
level. Refer to page 5-7.
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These settings are saved with the scenario.
Table 5-2. Animation options
Field
Description
Start Time
The time at which you wish to begin animation.
End Time
Specify time of animation:
Loop at Time
♦
End Time - The time at which animation ends.
♦
Loop Time - The time at which the animation loops
back to the Start Time. If this option is OFF,
animation continues until you pause or reset the
animation.
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Scenarios
Field
Description
Time Step
Specify the time lapse between animation steps.
X Real-Time
♦
Time Step - Amount of time for each animation step.
For example, if the Time Step field were set to 60
seconds, all vehicles in the scenario move forward 60
seconds each time the screen is refreshed.
♦
X Real-Time - The number of times faster than real
time at which you wish the scenario to animate.
♦
Real-Time - The scenario animates in real time in
accordance with your computer’s internal clock.
Real-Time
Refresh Delta
High Speed
+LQW
1RWH
Specify the amount of time between screen refresh updates.
♦
Refresh Delta - The amount of time between refresh
updates. For instance, if you enter 1.0, STK attempts
to refresh the screen once every second. The actual
refresh delta is limited by the minimum time
necessary to redraw your screen. The refresh time
varies with processor performance, graphics hardware
options, and scenario complexity.
♦
High Speed - STK refreshes the screen as fast as the
system is able. It doesn’t rely on a timer to begin the
refresh process.
You can also set the Start and End Times for the scenario by typing Now, Today or
Tomorrow in the appropriate fields. These settings reference the current date and time
based on the computer’s internal clock. If you save a scenario that includes these settings,
the animation time of that field is updated every time the scenario is opened to
correspond to the current date and time or the next day.
If you select Real-Time, ensure that the setting of your real-time clock is within the time
window of your scenario or no activity occurs in the Map window when the scenario is
animated.
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Satellite Tool Kit® User’s Manual
Scenarios
Basic Properties: Setting Units of
Measure
The options in the Units tab enable you to establish the default settings for
all units of measure used in a scenario. These settings are used for display and
data input purposes throughout STK.
To choose the unit of measure to be used throughout the scenario, highlight
the unit of interest in the Units list, then highlight the unit value you wish to
set as the default in the Change Unit Value list. The value now displays to the
right of the unit in the Units list. For any changes to take effect, you must
click OK or Apply.
For the purposes of this manual, scenario units are assumed to be Degrees, Seconds,
Kilograms, Meters and UTC Gregorian. If you select different scenario units, the fields and
entries in your windows may appear slightly different from those shown in this manual.
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5-7
Scenarios
Table 5-3. Units options
Field
Description
Distance Unit
Distance can be displayed in one of the following units:
Time Unit
Date Format
5-8
♦
Feet (ft)
Š Statue Miles (mi)
♦
Nautical miles (nm)
Š Meters (m)
♦
Kilometers (km)
Š Astronomical units (au)
♦
Earth radii (re)
Time can be displayed in any one of the following units:
♦
Seconds (sec)
Š Minutes (min)
♦
Hours (hr)
Š Days (day)
Dates can be displayed in a variety of formats. Available formats are:
♦
Epoch Seconds (EpSec) - Date calculated in seconds relative to
the epoch date specified in the scenario’s Time Period tab.
♦
Epoch Minutes (EpMin) - Date calculated in minutes relative to
the epoch date specified in the scenario’s Time Period tab.
♦
Epoch Hours (EpHr) - Date calculated in hours relative to the
epoch date specified in the scenario’s Time Period tab.
♦
Epoch Days (EpDay) - Date calculated in days relative to the
epoch date specified in the scenario’s Time Period tab.
♦
Local Gregorian (LCLG) - Local time zone date and time
displayed in Gregorian format (1 Nov 1997 00:00:00.0000).
♦
UTC Gregorian (UTCG) - Universal Coordinated Time (UTC)
date and time displayed in Gregorian format (1 Nov 1997
00:00:00.0000).
♦
Local Julian (LCLJ) - Local time zone date and time displayed
in day of year format (306/97 00:00:00.0000).
♦
UTC Julian (UTCJ) - UTC date and time displayed in day of
year format (306/ 97 00:00:00.0000).
Satellite Tool Kit® User’s Manual
Scenarios
Field
Description
♦
YYDDD:ddd (YYDDD) - MSGP4 Epoch date format.
♦
Julian4 (UTCJ4) - UTC date and time displayed in day of
year format, with four digits representing the year (306/1997
00:00:00.0000).
♦
Julian Date (JDate) - Number of days from GMT Noon on
1 January, 4713 B.C.
♦
♦
YYYYDDD.hhmmss (YYYYDDD)
Julian Date Offset (JDateOff) - Number of days from GMT
Noon with user-specified offset.
♦
Mission Elapsed (MisElap) - Time since user-specified
epoch. Enter epoch in text field (D/HH:MM:SS.SS). See
warning following this table.
Angle Unit
Mass Unit
Angles can be displayed in:
♦
Degrees (deg)
Š Radians (rad)
♦
Arc seconds (arcSec)
Š Arc minutes (arcMin)
♦
Degrees, minutes, seconds (DMS)
♦
Hours, minutes, seconds (HMS)
Two units of measure are available for mass:
♦
Kilograms (kg)
Š Pounds (lb) -1 pound mass
weighs 1 pound on the surface
of the Earth
Power Unit
Power can be displayed in one of the following units:
♦
Milliwatts (mW)
Š Gigawatts (GW)
♦
Watts (W)
Š dBm (dBm)
♦
Kilowatts (KW)
Š dBW (dBW)
♦
Megawatts (MW)
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Scenarios
Field
Description
Frequency
Unit
Frequency can be displayed in one of the following units:
Small Distance
Unit
Latitude Unit
Longitude
Unit
♦
Hertz (Hz)
Š Kilohertz (KHz)
♦
Megahertz (MHz)
Š Gigahertz (GHz)
♦
Terahertz (THz)
Small Distance Units are used to describe distances smaller than a
meter. Choices are:
♦
Inches (in)
Š Microns (um)
♦
Centimeters (cm)
Š Nanometers (nm)
♦
Millimeters (mm)
Š Meters (m)
♦
Feet (ft)
These two units of measure can be displayed in one of the following
units:
♦
Degrees (deg)
♦
Radians (rad)
♦
Degrees, minutes, seconds (DMS)
♦
Hours, minutes, seconds (HMS)
Typically, you may use either of the three-unit combinations to
pinpoint a facility position, for example.
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You can enter data in STK using any unit of measure; STK converts the values entered to
the option selected in the Units tab.
If you wish to specify Date Units as Mission Elapsed, it is best to enter the dates in the Time
Period and Animation tabs before you change the Date Unit to Mission Elapsed. This is
because the Mission Elapse Time is measured relative to the existing scenario epoch.
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Scenarios
Entering Units in Text Fields
Values can be entered into text fields within STK using any valid unit for the
dimension being entered. For example, if you wish to enter a value in a text
field associated with time, the value can be entered in seconds, hours, minutes
or days. This is true regardless of the current units selected—STK converts
the values entered to the unit specified in the Units tab. Abbreviations that
can be entered are shown in parenthesis in the previous table.
Basic Properties: Setting Default
Databases
The Database tab allows you to set the default databases for the city, facility,
satellite and star databases. You can specify a database shipped with STK or
one of your own that conforms to STK's format requirements.
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Scenarios
The options in the Database tab are described in the table following.
Table 5-4. Database options
PRO/
Terrain
Option
Description
Database Type
Choose among City, Facility, Satellite, and Star.
Database Defaults
Specify the name of the database to be used and the directory
in which it is located.
Auxiliary Database
If you wish to use a database in addition to the one specified
in the Database Defaults field, turn the Use Auxiliary
Database option ON and specify the database name and
location. The database must conform to STK's format.
Basic Properties: Terrain
The Terrain tab allows you to select terrain elevation data for facility and
target azimuth-elevation mask and position.
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Scenarios
The Terrain module provides precise three-dimensional (3-D) terrain
elevation data for the entire globe. When used with STK, Terrain exploits
sophisticated multi-dimensional interpolation algorithms to provide accurate
360° azimuth/elevation masks for satellite access calculations from any point
on the Earth’s surface. These algorithms also provide altitude information for
user defined facilities and ground based targets. For users of the VO module,
Terrain allows a vivid 3-D visual depiction of the Earth’s true surface relief
and its effect on satellite accesses.
The data has a resolution of less than 30 arc-seconds or approximately 1
kilometer at the Earth’s surface. In its compressed format, the complete data
set requires over 400 MB of storage. However, the data can be read directly
from a CD-ROM without loading it onto your hard disk. This data was
originally compiled by the U. S. Geologic Survey from a variety of sources
around the world. It has been processed and formatted for optimal
performance with STK.
Use the Up and Down arrows to order the data for level of details and
viewing purposes. The order in which the terrain data appears in this list is
the order in which STK searches for terrain data.
Use the Remove button to remove selected terrain data files from the list.
Adding Terrain Elevation Data
Use the Add… button to select terrain elevation data from a CD-ROM or
another location for inclusion in the search list.
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Scenarios
Once you specify the file to be used, general terrain information appears in
the lower portion of the window so that you can verify that the file is the one
you wish to use.
Use the Location field to specify the directory and file name of the terrain file.
Once you’ve selected the file, click OK to add the data to the search list.
Graphics Properties: Global Attributes
The Global Attributes tab allows you to set certain options globally so that all
objects within the scenario inherit the attributes.
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Scenarios
Fields available in the Global Attributes tab are described in the table
following.
Table 5-5. Global attributes
Option
Description
Show Labels
If ON, objects display in the Map window with text labels.
Show Ground
Tracks
If ON, vehicle ground tracks display in the Map window.
Show Pass Labels
If ON, vehicle (i.e., satellite, aircraft, ship, etc.) pass numbers
display in the Map window.
Show El Set
Number
This option only affects MSGP4 satellites with multiple twoline element sets. If ON, element set numbers for the vehicle
display in the Map window.
Show Orbits
This option only affects the Perspective map projection (refer
to Chapter 3, The Map Window). If ON, satellite orbital tracks
display in the Map window.
Show Sensors
If ON, sensor projections display in the Map window.
Show Turn
Markers
This option only affects aircraft, ground vehicles and ships. If
ON, turn markers specified for the Great Arc vehicle display in
the Map window.
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Scenarios
Option
Description
Blink on Select
If ON, the graphics associated with the selected object blink
when the object is highlighted in the Browser window. This
feature is especially useful in scenarios containing a large
number of objects.
Graphics Properties: Sun Lighting
The Sun Lighting tab allows you to graphically display the lighting
conditions for the scenario during animation.
Fields available in the Sun Lighting tab are described in the table below.
Table 5-6. Sun lighting options
5-16
Field
Description
Subsolar Point
If ON, the point on the Earth directly below the Sun
displays in the Map window.
Satellite Tool Kit® User’s Manual
Scenarios
Field
Description
Sunlight/ Penumbra
If ON, the boundary where the Sun completely appears or
just begins to disappear at the horizon displays at the
specified Display Altitude in the Map window.
Penumbra/ Umbra
If ON, the boundary where the Sun completely disappears or
just begins to appear at the horizon displays at the specified
Display Altitude in the Map window.
Display Altitude
The altitude at which the Subsolar Point, Sunlight/Penumbra
and Penumbra/Umbra is depicted.
Color
Select the color of the lines or markers.
Line/ Marker Style
The marker style for the subsolar point or line style.
Line Widths
1 = narrow, 5 = wide.
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6
SATELLITES
Overview
This chapter describes orbiting satellites, and provides instructions for setting the
basic and graphics properties as well as the access constraints of satellites. It also
provides instructions for manipulating satellites to obtain the information you need
for analysis and problem-solving.
Chapter Contents
Basic Properties: Orbit ..................................................................................6-3
Two-Body, J2 Perturbation & J4 Perturbation Propagators ..........................6-3
Orbit Epoch ............................................................................................6-4
Coordinate Epoch ..................................................................................6-4
Coordinate Type .....................................................................................6-4
Coordinate Systems - Standard .............................................................6-12
Coordinate Systems - Advanced Analysis Module.................................6-13
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Satellites
Special Options .....................................................................................6-14
HPOP Propagator (Module).......................................................................6-15
Force Models ........................................................................................6-15
Long-term Orbit Predictor (Module)...........................................................6-18
Force Models ........................................................................................6-18
MSGP4 Propagator ....................................................................................6-22
Managing TLE Sets................................................................................6-24
Custom Propagator (StkExternal) ...............................................................6-27
Basic Properties: Attitude ............................................................................6-28
Attitude Type Selection..........................................................................6-29
Orientation Type...................................................................................6-34
Integrated Attitude................................................................................6-35
Target Pointing .....................................................................................6-36
Basic Properties: Pass Break ........................................................................6-38
Basic Properties: Mass.................................................................................6-40
Graphics Properties: Attributes ...................................................................6-41
Graphics Properties: Pass............................................................................6-42
Graphics Properties: Display Times.............................................................6-44
Graphics Properties: Contours ...................................................................6-45
Constraints: Basic .......................................................................................6-47
Constraints: Sun .........................................................................................6-50
Constraints: Temporal ................................................................................6-52
Constraints: Advanced ...............................................................................6-54
6-2
Satellite Tool Kit® User’s Manual
Satellites
Basic Properties: Orbit
To generate an orbit for a satellite, open the Basic Properties window for the
satellite. In the Orbit tab, you can use a number of different propagators to
define the satellite’s orbit. At the top of this panel, the Start Time and Stop
Time fields specify the temporal boundaries of your satellite. The default
values for Start Time and Stop Time are your scenario start and stop times. The
Step Size field specifies the interval between calculated ephemeris output
points. The default value is 60 seconds.
The fields available in the bottom portion of the Orbit tab depend on the
Propagator chosen. A propagator uses an analytical formulation of the timedependent motion of a satellite to produce ephemeris or to directly provide
the position and velocity of a satellite at a particular time. The propagators
available for a satellite are discussed in the sections following.
Two-Body, J2 Perturbation & J4
Perturbation Propagators
The Two-Body, J2 Perturbation and J4 Perturbation propagators all require the
same fields of information to be defined. A Two-Body, or Keplerian motion,
propagator considers the Earth to be a point mass with no perturbations. J2
Perturbation (first-order) and J4 Perturbation (second-order) propagators account
for secular variations in the orbit elements due to Earth oblateness. These
propagators don’t model atmospheric drag or solar or lunar gravitational forces.
J2 and J4 are zonal harmonic coefficients in an infinite series representation of the
Earth’s gravity field. J2 is approximately 1000 times larger than J4 and is a result of
Earth oblateness. The even zonal harmonic coefficients of the gravity field are the
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6-3
Satellites
only coefficients that result in secular changes in satellite orbital elements. The J2
propagator includes the first-order secular effects of the J2 coefficient while the J4
propagator includes the first- and second-order effects of J2 and the first-order
effects of J4. The J3 coefficient, which produces long period periodic effects, isn't
included in either propagator. Since the second-order J2 and the first-order J4
secular effects are very small, there is little difference between the orbits generated
by the two propagators.
Orbit Epoch
The Orbit Epoch defines the time at which the established orbit elements (on
the right-hand side of the tab) are true.
Coordinate Epoch
The Coordinate Epoch specifies the epoch of your input coordinate system.
Some STK coordinate systems require an epoch in order to be fully defined.
If you select a system with a pre-established coordinate epoch (such as J2000
or B1950), the Coord Epoch field is disabled.
Coordinate Type
There are six different coordinate types, discussed in the subsections
following. Each coordinate type is a unique representation of the position
and velocity of the satellite. Some of the individual elements have two or
more options. Fields available in the lower portion of the window depend on
the option you choose for the coordinate type.
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Satellite Tool Kit® User’s Manual
Satellites
Classical Coordinate Type
Classical coordinates consist of the
traditional osculating Keplerian orbital
elements that allow you to specify the shape
and size of an orbit. Some of these orbital
elements, described in the table below, are
paired and only certain combinations are
valid.
The classical coordinate type is only available when an inertial coordinate system is
selected.
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Table 6-1. Description of classical orbital elements
Element
Description
Orbit Size and
Shape (includes
first 2 fields)
The first two fields are linked. If you choose one, the other element also
appears. Choose one of the following pairs:
♦
Semimajor Axis/Eccentricity (default) - Half the length of the major
axis of the orbital ellipse. Eccentricity describes the shape of the ellipse
(where 0 = a perfectly circular orbit).
♦
Apogee Radius/Perigee Radius - Measured from the center of the
Earth to the points of maximum and minimum radius in the orbit.
♦
Apogee Altitude/Perigee Altitude - Measured from the “surface” of
the Earth (a theoretical sphere where the radius equals the equatorial
radius of the Earth) to the points of maximum and minimum radius
in the orbit.
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Satellites
Element
Description
♦
Period/Eccentricity. The Period is the duration of one orbit, based on
assumed two-body motion.
♦
Mean Motion/Eccentricity. Mean Motion identifies the number of
orbits per day (86400 sec/period), based on assumed two-body
motion.
♦
Inclination - The angle between the angular momentum vector
(perpendicular to the plane of the orbit) and the inertial Z axis.
♦
Argument of Perigee - The angle from the ascending node to the
eccentricity vector (lowest point of orbit) measured in the direction
of the satellite’s motion and in the orbit plane. The eccentricity vector
points from the center of the Earth to perigee with a magnitude equal
to the eccentricity of the orbit. For a circular orbit, the argument of
perigee is defined to be zero (perigee at the ascending node).
The last of three elements describing orientation allows you to specify the
orientation of the orbital planes. Choose either:
6-6
♦
Right Ascension of the Ascending Node (default) - The angle from
the inertial X axis to the ascending node measured in a right-handed
sense about the inertial Z axis in the equatorial plane. In the case of an
equatorial orbit, the ascending node is defined to be directed along
the reference frame's positive x axis, thus Ω = 0.
♦
Longitude of the Ascending Node - The Earth-fixed longitude where
your satellite crosses the inertial equator (the intersection of the
ground track and the inertial equator) from south to north. The
specified ascending node crossing is assumed to be at, or prior to, the
initial condition of the orbit.
Satellite Tool Kit® User’s Manual
Satellites
Element
Description
Satellite Location
Specify a satellite’s location within its orbit at epoch:
•
True Anomaly (default) - The angle from the eccentricity vector
(points toward perigee) to the satellite position vector, measured in
the direction of satellite motion and in the orbit plane.
•
Mean Anomaly - The angle from the eccentricity vector to a position
vector where the satellite would be if it were always moving at its
average angular rate.
•
Eccentric Anomaly - An angle measured with an origin at the center
of an ellipse from the direction of perigee to a point on a
circumscribing circle from which a line perpendicular to the
Semimajor Axis intersects the position of the satellite on the ellipse.
♦
Argument of Latitude - The sum of the True Anomaly and the
Argument of Perigee.
♦
Time Past Ascending Node - The elapsed time since the last
ascending node crossing.
♦
Time Past Perigee - The elapsed time since the last perigee passage.
Figure 6-1. Classical coordinate relationships
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Satellite Tool Kit® User’s Manual
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6-7
Satellites
Cartesian
Coordinate Type
The Cartesian coordinate type displays fields
that allow you to enter the initial X, Y, and Z
position of your satellite as well as the satellite’s
initial X, Y, and Z velocities using the type of
Coordinate System selected.
Equinoctial Coordinate Type
(Advanced Analysis Module)
PRO/
Advanced
Analysis
Equinoctial uses the center of the Earth as the
origin and the plane of the satellite’s orbit as
the reference plane.
The equinoctial coordinate type is only available when
an inertial coordinate system is selected.
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The advantage of this element set is that singularities are limited to
retrograde equatorial orbits, parabolic/ hyperbolic orbits and collision orbits.
The Keplerian element Ω (right ascension of ascending node) is undefined
when the inclination is 0 and is numerically unstable for inclination near 0.
As the inclination approaches zero, the line of nodes becomes indeterminate.
The Keplerian element ω (argument of perigee) becomes singular when the
eccentricity is zero. As eccentricity approaches zero, the line of apsides
becomes indeterminate. The Air Force Satellite Control Network (AFSCN)
typically solves for the equinoctial elements during the orbit estimation
process.
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Satellite Tool Kit® User’s Manual
Satellites
Table 6-2. Equinoctial coordinate type elements
Option
Description
Semimajor Axis
Half the length of the major axis of the orbital ellipse.
h/k/p/q
h / k collectively describe the shape of the satellite’s orbit and
the position of perigee. p / q collectively describe the
orientation of the satellite’s orbit plane.
Mean Longitude
Specifies a satellite’s position within its orbit at epoch and
equals the sum of the classical Right Ascension of the
Ascending Node, Argument of Perigee, and Mean Anomaly.
Direction
Choose either:
♦
Retrograde, where inclination is greater than 90°.
♦
Posigrade, where inclination is between 0° and 90°,
inclusive.
Delaunay Variables Coordinate Type
(Advanced Analysis Module)
PRO/
Advanced
Analysis
Delaunay variables are a set of canonical
angle-action variables commonly used in
general perturbation theories. The element
set consists of three conjugate angle-action
pairs. The angles are represented by lower
case letters and the conjugate actions are
represented by upper-case letters.
The delaunay variables coordinate type is only available when an inertial coordinate
system is selected.
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There are two options for the representation of each action variable. The
default representation gives the canonical actions used in Hamilton’s
equations of motion. The other representation, which divides the actions by
Satellite Tool Kit® User’s Manual
6-9
Satellites
the square root of the central-body gravitational constant, yields a geometric
version of the Delaunay set that is independent of the central body.
◊
L is related to the two-body orbital energy.
◊
G is the magnitude of the orbital angular momentum.
◊
H is the Z component of the orbital angular momentum.
The above components are expressed in terms of distance squared, divided by
time, where distance is measured in standard units and time is measured in
seconds.
PRO/
Advanced
Analysis
Mixed Spherical Coordinate Type
(Advanced Analysis Module)
Mixed Spherical coordinates are a variation of
the spherical elements combining Earth-fixed
position parameters with inertial velocity
parameters. Also known as DODS elements.
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The mixed spherical coordinate type is only
available when an inertial coordinate system is
selected.
If you entered the predicted orbital elements and propagated a satellite that is about to
launch, it is possible that the launch may not occur at the exact time predicted. A quick
way to adjust the elements and repropagate is to switch the Coordinate Type to Mixed
Spherical and change the orbit epoch to the new time. The Mixed Spherical Coordinate Type
is independent of the orbit epoch.
Table 6-3. Mixed spherical coordinate type elements
6-10
Option
Description
Longitude
Measured from -180.0° to +360.0°
Satellite Tool Kit® User’s Manual
Satellites
Option
Description
Geodetic Latitude
Measured from -90.0° to +90.0°. The geodetic latitude of a
point is the angle between the normal to the reference
ellipsoid which passes through the satellite position and the
equatorial plane.
Altitude
The object’s position above or below the reference ellipsoid.
Altitude is measured along a normal to the surface of the
reference ellipsoid.
Hor FPA/ Ver FPA
Horizontal or vertical flight path angle. The angle between
the inertial velocity vector and the radius vector (vertical) or
the complement of this angle (horizontal).
Azimuth
The angle in the satellite local horizontal plane between the
projection of the inertial velocity vector onto this plane and
the local north direction measured as positive in the clockwise
direction.
Velocity
The magnitude of the inertial velocity vector.
Spherical Coordinate Type (Advanced
Analysis Module)
PRO/
Advanced
Analysis
Spherical elements allow you to define the
path of an orbit using polar rather than
rectangular coordinates.
Table 6-4. Spherical elements
Option
Description
Right Ascension of the
Ascending Node (RAAN)
(inertial)/ Longitude (fixed)
RAAN is defined as the angle from the X axis to the
projection of the satellite position vector in the
equatorial plane measured as positive in the direction of
the Y axis.
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6-11
Satellites
Option
Description
Declination (inertial)/
Latitude (fixed)
Declination is defined as the angle between the satellite
position vector and the inertial equatorial plane
measured as positive toward the positive inertial Z axis.
Radius
The magnitude of the satellite position vector.
Flight Path Angle
The angle between the velocity vector and the radius
vector (vertical) or the complement of this angle
(horizontal).
Azimuth
The angle in the satellite local horizontal plane between
the projection of the velocity vector onto this plane and
the local north direction measured as positive in the
clockwise direction.
Velocity
The magnitude of the velocity vector.
Coordinate Systems - Standard
All coordinate systems in STK are a right-handed Cartesian coordinate
system with the origin at the center of the Earth.
Table 6-5. Standard coordinate systems
6-12
Option
Description
Fixed
X is fixed at 0° longitude, Y is fixed at 90° longitude, and
Z is directed toward the north pole.
J2000
X and Z axes point toward the mean vernal equinox and
mean rotation axis of the Earth at January 1, 2000 at
12:00:00.00 TDT, which corresponds to JD 2451545.0.
Satellite Tool Kit® User’s Manual
Satellites
Option
Description
B1950
X and Z axes point toward the mean vernal equinox and
mean rotation axis of the Earth at the beginning of the
Besselian year 1950 (when the longitude of the mean Sun
is 280.0° measured from the mean equinox) and
corresponds to 31 December 1949 22:09:07.2 or JD
2433282.423.
Alignment at Epoch
Defines the ECF and ECI systems as in alignment at the
Orbit Epoch, using ECF as the baseline and adjusting
ECI to it. Often used to specify launch trajectories.
PRO/
Advanced
Analysis
Coordinate Systems - Advanced
Analysis Module
The following coordinate systems are available with the Advanced Analysis
module.
Table 6-6. AAM Coordinate systems
Option
Description
Mean of Date
X and Z axes point towards the mean vernal equinox and mean
rotation axis of the Earth at the Orbit Epoch.
Mean of Epoch
X and Z axes point toward the mean vernal equinox and mean
rotation axis of the Earth at the Coord Epoch.
True of Date
X and Z axes point toward the true vernal equinox and true
rotation axis of the Earth at the Orbit Epoch.
True of Epoch
X and Z axes point toward the true vernal equinox and true
rotation axis of the Earth at the Coord Epoch.
Mean Equinox
True Equator
X and Z axes point toward the mean vernal equinox and true
rotation axis of the Orbit Epoch.
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Satellites
Special Options
STK allows you to set special options for the propagator that take into
account elliptical factors. For the J2 and J4 propagators, use the Special
Options… button to display the Special Options window. This option is not
applicable to the Two-Body propagator.
Table 6-7. Ellipse options
6-14
Option
Description
Osculating
Representative of the particular point on a satellite trajectory
but the actual trajectory differs from its two-body counterpart
at other points in time. If ON, the relationship among the
Semimajor Axis length, nodal Mean Motion and Period of the
satellite is different from the relationships observed in the Path
tab. The variation is due to the fact that conversions on the
Path tab are performed assuming two-body motion.
Satellite Tool Kit® User’s Manual
Satellites
Option
Description
Secularly Precessing
Remains constant in shape and size but changes orientation in
a continuous, consistent manner. If ON, the conversions
between Semimajor Axis, nodal Period and Mean Motion
considers the precession of the orbit. In this way, you can
accurately specify nodal periods in the J2 and J4 propagators
to assist in the design of orbits with strict period requirements
or repeating ground tracks.
HPOP Propagator (Module)
The High-Precision Orbit Propagator (HPOP) can handle circular, elliptical,
parabolic and hyperbolic orbits at distances ranging from the surface of the
Earth to the orbit of the Moon and beyond, although orbits around the
Moon itself are not currently supported.
The HPOP propagator uses the same orbital elements as those required by the
Two-Body, J2 and J4 propagators. For more information about the fields
available for the HPOP propagator, refer to page 6-4 of this chapter.
Technical notes about the HPOP propagator are also available as Appendix
D of this manual
Force Models
The Force Models… button of the Orbit tab allows you to set advanced
options for the HPOP propagator.
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Satellites
The fields available in the HPOP Force Model window are described in
the table following.
Table 8. Force model options
Option
Description
Earth Gravity
Specify:
Drag
6-16
♦
Maximum Degree - The maximum degree of
Geopotential coefficients to be included for
Earth gravity computations. Valid range is from
0 to 70.
♦
Maximum Order - The maximum order of
Geopotential coefficients to be included for
Earth gravity computations. Valid range is from
0 to the Maximum Degree.
Specify the following:
♦
CD - Coefficient of drag
♦
Atmosphere Density Model
♦
Additional parameters depending on model
selected (see table below).
Satellite Tool Kit® User’s Manual
Satellites
Option
Description
Solar Radiation Pressure
If ON, specify the coefficient of solar radiation pressure.
Third-Body Gravity
Choose to include one or both:
Physical Data
♦
Solar Gravity - Effects of solar gravity on the
satellite.
♦
Lunar Gravity - Effects of lunar gravity on the
satellite.
Enter the area/mass ratio in square meters per kilogram.
The size of the gravity field used greatly affects the time required to compute the orbit of
the satellite. For this reason, we recommend that lower degrees and order be specified
when generating orbits for basic studies.
The following atmospheric density models are available for the HPOP force
model:
Table 9. Atmospheric Density Models
Option
Description
1976 Standard
A table lookup model based on the satellite’s altitude. Its
range of validity is 86km - 1000 km. No additional
parameters need be specified.
Harris-Priester
Takes into account a 10.7 cm solar flux level, and has
been modified in STK also to take into account diurnal
bulge. Its range of validity is 0 - 1000 km, and it requires
specification of one additional parameter: Average
F10.7.
Jacchia 1971
Computes atmospheric density on the basis of the
composition of the atmosphere, which depends on the
satellite’s altitude as well as seasonal variation. Its range
of validity is 100km - 2500 km. Two additional
parameters need to be specified: Average F10.7 and
Geomagnetic Index (Kp).
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Long-term Orbit Predictor (Module)
The Long-term Orbit Predictor (LOP) allows accurate prediction of a
satellite’s orbit over many months or years. This is often used for long
duration mission design, fuel budget definition and end-of-life studies. For
performance reasons, it is impractical to compute the long-term variation in a
satellite’s orbit using high-accuracy, small-time step, propagators that
compute a satellite’s position as it moves through its orbit. LOP exploits a
“variation of parameters” approach that integrates analytically derived
equations of motion, computing the average effects of perturbations over an
orbit. This approach allows large multi-orbit time steps and typically
improves computational speed by several hundred times while still offering
high fidelity computation of orbit parameters.
LOP implements the 1976 Standard Atmosphere to compute drag effects.
Additionally, LOP considers the effects of the Earth’s oblateness (through
J21), the resonant effects of tesseral harmonics, solar and lunar gravity, and
solar radiation pressure when computing the orbital perturbations. The
module is based on algorithms developed at NASA’s Jet Propulsion
Laboratory.
The LOP propagator uses the same orbital elements as those required by the
Two-Body, J2 and J4 propagators. For more information about the fields
available for the LOP propagator, refer to page 6-4 of this chapter.
Force Models
The Force Models… button of the Orbit tab allows you to set advanced
options for the LOP propagator.
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The fields available in the LOP Force Model window are described in the
table following.
Table 10. Force model options
Option
Description
Earth Gravity
Specify:
Drag
♦
Maximum Degree - The maximum degree of
Geopotential coefficients to be included for Earth
gravity computations. Valid range is from 2 to 210.
♦
Maximum Order - The maximum order of
Geopotential coefficients to be included for Earth
gravity computations. Valid range is from 0 to the
Maximum Degree.
Specify all of the following:
♦
CD - Coefficient of drag
♦
Advanced Settings - Refer to section immediately
following.
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Option
Description
Third-Body
Gravity
Choose to include one or both:
♦
Solar Gravity - Effects of solar gravity on the satellite.
♦
Lunar Gravity - Effects of lunar gravity on the satellite.
Solar Radiation
Pressure
If ON, specify the coefficient of solar radiation pressure and the
atmospheric height.
Physical Data
Specify:
♦
Drag Cross-sectional Area - The satellite’s crosssectional area to be used in atmospheric drag
calculations.
♦
SRP Cross-sectional Area - The satellite’s cross-sectional
area to be used in solar radiation pressure calculations.
♦
Mass - The mass of the satellite to be used in
atmospheric drag and solar radiation pressure
calculations.
The size of the gravity field used greatly affects the time required to compute the orbit of
the satellite. For this reason, we recommend that lower degrees and order be specified
when generating orbits for basic studies.
Advanced Settings
Use the Advanced Settings… button to further define the drag model to be
used for calculations.
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Use either the 1976 Standard Atmosphere Model or the Exponential Density
Model to calculate atmospheric density. If you choose the Exponential
model, use the following formula to calculate the atmospheric density
at any given altitude:
ρ = ρ oe
h0 − h
H
where:
ρ equals the density at the user-specified altitude
h equals the user-specified altitude
ρO equals the reference density
hO equals the reference height
H equals the scale height
If you use the 1976 model, choose to turn the Use Osculating Altitude option
ON to use a short period variation due to J2 perturbations when calculating
altitude.
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Satellites
Use the Maximum Drag Altitude option to specify the altitude above which
drag calculations aren’t considered. Use the Density Weighting Factor to
specify the scale factor for the density calculations.
MSGP4 Propagator
The Merged Simplified General Perturbations (MSGP4) propagator (standard
NORAD propagator) is used with two-line mean element (TLE) sets. It
considers secular and periodic variations due to Earth oblateness, solar and
lunar gravitational effects, gravitational resonance effects and orbital decay
using an atmospheric drag model.
1RWH
The term “merged” refers to the fact that the algorithm used for orbits with Periods below
approximately 225 minutes is the Simplified General Perturbations (SGP4) propagator and,
for higher orbits, the algorithm used is the Simplified Deep Space General Perturbations
(SDP4) propagator.
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For information on SDP4 and SGP4 propagators, you can obtain a copy of Space Track
Report #3 from the U. S. Air Force Space Command, or by contacting Analytical Graphics.
The mean orbital elements and file references required by the MSGP4 propagator
are explained below.
Table 6-11. MSGP4 orbital elements
Element
Description
SSC Number
The catalog number of the spacecraft, if created by a 2-line
element set.
Orbit Epoch
The universal date and time at which the specified orbit
elements are true. The format is YYDDD.DDDDDDDD.
Mean Motion
The number of revolutions per day.
Eccentricity
Describes the shape of the ellipse. A value of 0 represents a
perfectly circular orbit; a value of 1 represents a parabolic path.
Inclination
The angle between the angular momentum vector
(perpendicular to the plane of the orbit) and the inertial Z axis.
Argument of
Perigee
The angle from the ascending node to the eccentricity vector
(lowest point of orbit) measured in the direction of the
satellite’s motion. The eccentricity vector points from the
center of the Earth to perigee with a magnitude equal to the
eccentricity of the orbit.
Right Ascension
The angle from the inertial X axis to perigee. The ascending
node is the point where the satellite passes through the inertial
equator moving from south to north. Right ascension is
measured as a right-handed rotation about the inertial Z axis.
Mean Anomaly
The angle from the eccentricity vector to a position vector
where the satellite would be if it were always moving at its
average angular rate.
Mean Motion Dot
The first time derivative of mean motion.
Motion Dot Dot
The second time derivative of mean motion.
Bstar
The drag term for your satellite.
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Satellites
The satellite’s SSC Number must be correct to use the TLE Selection feature since TLE searches are
based on the SSC Number.
:DUQLQJ
Managing TLE Sets
At the bottom of the MSGP4 Path tab is a slide bar that can be used to view
the contents of multiple TLE sets. To view a given TLE set, click the slide
button and drag the mouse along the slide. The number assigned to the
element set displays directly above the slide. Simply stop the slide at the
correct number to view the TLE set of your choice.
:DUQLQJ
If you delete an element using the Delete button, make sure that you’re deleting the
correct element set (i.e., the set deleted is the currently visible one).
Load
You can load or insert a TLE set from a file by using the Load button.
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Table 6-12. TLE selection options
Option
Description
Load Method
Defines how the TLE sets are loaded.
♦
Auto Load - Causes STK to automatically load TLE sets
corresponding to the SSC number of the satellite when
the satellite is loaded.
♦
File Load - Load the selected TLE data and replace all
previous TLE data currently associated with the satellite.
♦
File Insert - Add the selected TLE data but keep previous
TLE data currently associated with the satellite.
♦
Online Load - Go directly to Analytical Graphics, Inc.
World Wide Web site to download the latest TLE sets.
Max TLE Limit
Limit the number of TLE sets that can be saved with the satellite.
If the limit set in the Max TLE Limit field is exceeded, STK
purges the oldest TLE data based on the TLE Epoch date.
TLE File
Displays the selected TLE file.
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Option
Description
TLE Selection
Displays one or more TLE sets.
Advanced
Advanced options for multiple TLE sets are available using the Advanced
button.
The fields available in this window are discussed in the table following.
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Table 6-13. TLE advanced options
Option
Description
Switching Method
Defines when to switch between TLE sets.
♦
Epoch - Epoch of the TLE.
♦
Mid-Point - Mid-point between two TLE epochs.
♦
TCA - Time of Closest Approach. Calculated by
propagating the first and second TLE sets over the
time period between two their respective epochs, and
then determining the closest point between the two
paths. This option provides the smoothest possible
switch between two TLE sets.
♦
Override - Set the switching time between two TLE
sets using the Start Time field.
♦
Disable - Ignore the selected TLE set (if you attempt
to disable all of them, STK will use the first in the
time period).
Start Time
Set the time at which the switch between one TLE set and a
second set occurs. Only available for the Manual Switching
Method.
Range
Not an editable field. Displays how far apart the satellites are
when switching occurs.
Element Set Number
Use the scroll bar to select the second of two TLE sets (2-n),
then set the switching options for the TLE in this window.
Custom Propagator (StkExternal)
The StkExternal propagator allows you to read the ephemeris for a satellite
from a file. For information about the ephemeris file format, refer to
Appendix C of this manual.
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Turn the External Ephemeris option ON, then specify the file of choice. The
file must end in a .e extension.
Basic Properties: Attitude
The Attitude tab of the Basic Properties window for a satellite can be used to
specify the orientation of your satellite.
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Attitude Type Selection
Each attitude type, described in the following two tables, has its own set of
associated input parameters. Most attitude profiles are generated through the
use of two vectors represented in the satellite body-fixed coordinate system,
and two vectors represented in the inertial coordinate system. The first
vector is referred to as the alignment vector; the second as the constraint
vector. The inertial-to-body-fixed quaternion is constructed so that the
representations of the alignment vectors in the body-fixed and inertial
coordinate systems are aligned. The quaternion is constructed so that the
angle between the constraint vectors in the body-fixed and inertial systems is
minimized while the colinear status of the alignment vectors is maintained.
The definitions of the alignment and constraint vectors for the different
attitude profile types are provided below.
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When an axis is constrained, that particular axis attempts to point to the desired location
as close as possible while still maintaining its proper relationship with the other axes
defined in the coordinate system. When an axis is aligned, that axis points directly to the
desired object, forcing the other axes to rotate accordingly.
Attitude Types - Standard
In each of the following attitude types, the satellite’s Z axis is aligned with
the nadir direction:
Table 6-14. Standard attitude types
+LQW
Attitude Type
Description
Nadir alignment
with ECF velocity
constraint
In this profile, the satellite’s Z axis is aligned with the nadir
direction and the satellite’s X axis is constrained in the
direction of the ECF velocity vector. The Constraint Offset
angle can be used to modify the body-fixed constraint vector.
This angle is measured from the X axis direction in a righthanded direction about the Z axis (i.e., to constrain with the Y
axis, set the offset to -90°). The Nadir alignment with ECF
velocity constraint profile may not be appropriate for satellites
in synchronous or highly eccentric orbits since the ECF
velocity vector may be poorly defined and/or alternating in
direction. Instead, use the Nadir alignment with ECI velocity
constraints profile.
Nadir alignment
with ECI velocity
constraint
The satellite’s Z axis is aligned with the nadir direction and the
X axis is constrained in the direction of the inertial velocity
vector. The Constraint Offset angle can be used to modify the
body-fixed constraint vector. This angle is measured from the
X axis direction in a right-handed direction about the Z axis
(e.g., to constrain with the Y axis, set the offset to -90°).
The ECF velocity alignment with radial constraint profile is most appropriate for surface
satellites and aircraft.
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Small animation time steps may be needed to properly visualize satellites with spinning
attitude profiles.
Other Attitude Types
A
A
STK also makes the following attitude types available:
Table 6-15. Other Attitude types (Advanced Analysis Module)
Attitude Type
Description
Nadir alignment
with Sun constraint
The satellite’s Z axis is aligned to nadir and the X axis is
constrained in the direction of the Sun. The Constraint Offset
angle, measured from the X axis direction in a right-handed
direction about the Z axis, is used to modify the body-fixed
constraint vector (e.g., to constrain with the Y axis, set the
offset to -90°).
Nadir alignment
with orbit normal
constraint
The satellite’s Z axis is aligned to nadir and the X axis is
constrained in the direction of the normal to the orbit plane.
The Constraint Offset angle is used to modify the body-fixed
constraint vector. This angle is measured from the X axis
direction in a right-handed direction about the Z axis (e.g., to
constrain with the Y axis, set the offset to -90°).
Sun alignment with
nadir constraint
The satellite’s X axis is aligned with the Sun direction and the
Z axis is constrained in the direction of nadir. The Alignment
Offset angle is used to modify the body-fixed alignment
vector. This angle is measured from the X axis direction in a
right-handed direction about the Z axis (e.g., to align with the
Y axis, set the offset to -90°).
Sun alignment with
ecliptic normal
constraint
The satellite’s X axis is aligned with the Sun direction and the
Z axis is constrained in the direction of the normal to the
ecliptic plane. The Alignment Offset angle is used to modify
the body-fixed alignment vector. This angle is measured from
the X axis direction in a right-handed direction about the Z
axis (e.g., to align with the Y axis, set the offset to -90°).
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Attitude Type
Description
Sun alignment with
ECI Z axis constraint
The satellite’s X axis is aligned with the Sun direction and the
Z axis is constrained in the direction of the ECI Z axis. The
Alignment Offset angle can be used to modify the body-fixed
alignment vector. This angle is measured from the X axis
direction in a right-handed direction about the Z axis (e.g., to
align with the Y axis, set offset to -90°).
Sun alignment Occultation Normal
constraint
The Occultation Normal attitude aligns the body X axis with
the Sun direction; the Z axis is constrained to be along the
Sun-Earth line.
ECI velocity
alignment with
nadir constraint
The satellite’s X axis is aligned with the inertial velocity
direction and the Z axis is constrained in the direction of nadir.
The Constraint Offset angle can be used to modify the bodyfixed constraint vector. This angle is measured from the Z axis
direction in a right-handed direction about the X axis (e.g., to
constrain with the Y axis, set the offset to +90°).
ECF velocity
alignment with
radial constraint
The satellite’s X axis is aligned with the Earth fixed velocity
direction and the Z axis is constrained in the direction opposite
to nadir. The Constraint Offset angle can be used to modify
the body-fixed constraint vector. This angle is measured from
the Z axis direction in a right-handed direction about the X
axis (e.g.., to constrain with the Y axis set the offset to +90°).
This attitude profile is commonly used for aircraft and surfacebased satellites.
Yaw to Nadir
The satellite’s Z axis is fixed in inertial space. The direction of
the satellite Z axis is specified through two angles, as
determined by the Orientation Type (see the following
section). The satellite X axis is then constrained, via motion in
the yaw sense, toward the nadir direction. This profile is useful
for satellites in highly elliptical orbits.
Satellite Tool Kit® User’s Manual
Satellites
Attitude Type
Description
Spinning
The satellite’s Z axis is assumed to be the spin axis and is fixed
in inertial space. The direction of the spin axis is specified
through two angles, as determined by the Orientation Type
(see the following section). The spin rate is specified in
revolutions per minute; positive values indicate rotation in a
right-handed sense with respect to the spin axis. The initial
orientation of the satellite is specified by using the spin offset
and offset epoch fields. The spin offset is an angular measure
of the difference between the satellite orientation at the offset
epoch from the orientation achieved by orienting the Z axis.
Spin about Nadir
The satellite’s Z axis is assumed to be the spin axis and aligned
to nadir. The other spin-related fields are defined in the same
manner as described for the spinning attitude above.
Spin About Sun
Vector
The body-fixed Z axis points to the Sun and the satellite
rotates about the Sun vector. The other spin-related fields are
defined in the same manner as described for the spinning
attitude above.
Inertially Fixed
Maintains a constant orientation of the body-fixed axes with
respect to the inertial coordinate system. The orientation of
the body-fixed axes is specified by three angles or a quaternion,
as determined by the Orientation Type (see the following
section).
External Attitude File
You can use external attitude data by entering an attitude file containing
quaternions. Turn the Attitude File option ON and specify the attitude file to
use. If ON, the file overrides the default attitude profile during the time span
of the quaternions contained in the file. The external attitude file format is
described in Appendix C of this manual.
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Satellites
Orientation Type
Use the Orientation Type option, only available for certain attitude types, to
select different sets of parameters for relating satellite body-fixed axes and
the inertial coordinate system.
Table 6-16. Orientation types
6-34
If you select…
You specify…
YPR Angles
Roll, pitch, and yaw angles. These angles are about the J2000
ECI inertial X, Y, and Z axes, respectively. Once you specify the
YPR angles, you also need to specify the rotation sequence.
Euler Angles
Euler A, Euler B, and Euler C angles. Once you specify the
Euler angles, you also need to specify the rotation sequence. The
numbers 1, 2 and 3 correspond to rotations about the current X,
Y, and Z axes, respectively. The common Euler sequence of a
rotation about the Z axis, followed by a rotation about the new
X axis, followed by a rotation about the new Z axis is specified as
a 313 sequence.
Quaternions
Specify the components of a quaternion. The first three fields
provide the vector part of the quaternion and the fourth field is
the scalar part. This quaternion represents the transformation
from the inertial coordinate system to the satellite body-fixed
coordinates. The quaternion must be normalized to unit length.
Quaternion input is only accessible when all three axis are being
specified.
RA/Dec
Right Ascension/Declination Angles. These angles specify the
direction of the satellite Z axis in spherical coordinates in the
inertial coordinate system. This input type is only available for
the specification of the Z axis.
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Satellites
Integrated Attitude
Use the Integrated Attitude button to generate an external attitude file by
numerically integrating Euler’s equations for the current satellite.
Use the fields in the Integrated Attitude window to specify the satellite’s
initial conditions. The initial orientation of the body to the inertial
coordinate system and the initial angular rate of the satellite in body-fixed
coordinates can be specified or you can initialize the attitude from the default
Attitude Type selected. STK uses the information entered here and data in the
inertia matrix to compute the satellite’s attitude over time.
Table 6-17. Integrated attitude options
Field
Description
Start/Stop Times
The start and stop times for the computation of the attitude.
Epoch
The time for which the initial conditions apply.
Torque File
The torque file defines a time-ordered list of body-fixed
torques to be applied to the satellite.
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Field
Description
Output Attitude File
STK automatically generates an attitude file based on the
values you’ve entered in this window. This file is formatted
correctly for subsequent use as an external attitude file.
Initialize from
Default Attitude
If ON, STK uses the default attitude data in the Attitude tab
to generate the initial conditions for the integration. If OFF,
you must define the initial orientation of the body in ECI
space and the initial angular velocity in the body-fixed frame.
Orientation Type
The initial orientation of the body and method of specification
(refer to orientation type on page 6-34).
Body-fixed Rates
The initial angular rates about the body’s X, Y and Z axes.
Target Pointing
A
A
You can point a satellite at selected targets so that the satellite’s Z axis points
in the direction of the target when the target is visible to the satellite based
on the assigned access constraints. Turn ON the Use Target Pointing Attitude
option, then use the Select Targets… button to choose the targets. A Target
Pointing Attitude window appears.
You can also point a satellite at a facility, area target or another satellite.
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Highlight the target you wish to select in the Available Targets list and use the
right arrow to move it to the Assigned Targets list.
Set the Slew Time for the time span in which you wish the satellite to change
from its original attitude to a target-pointing attitude and the amount of time
required to change its pointing to another target.
Target Times
You can also specify the time period during which the satellite points at the
selected target. In the Target Pointing Attitude window, highlight the target
of interest in the Assigned Targets list, then click use the Target Times…
button. A Target Schedule window appears.
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Satellites
You can choose to use the access times determined between the satellite and
the selected target by turning the Use Access Times option ON.
If you wish to define other times during which the satellite should orient
toward a selected target, enter the Start and Stop Times , then use the Add
button. To modify a time listed in the Scheduled Times list, highlight the time
period of interest so that the Start and Stop Times display in the text boxes,
then modify the values and use the Change button.
You can also choose whether the time intervals should be “deconflicted,” or
modified so that time periods set don’t overlap. If the Deconflict field is set to
Automatic, STK automatically modifies all time intervals during which an
overlap occurs so that the intervals are further segmented to avoid overlap. If
the field is set to None, no changes are made to time interval overlaps. If the
field is set to Manual, when an overlap occurs in the time interval list, an
Acknowledge window appears when you click the OK or Apply button to
alert you to the fact that the overlap exists. It is then your decision whether
to set the Deconflict field to Automatic so that the overlap is fixed, change the
time intervals yourself by modifying the appropriate entries in the list box, or
ignore the message and continue. If you ignore the message, the satellite
points at the first target until the target is no longer in sight.
Basic Properties: Pass Break
The Pass Break tab of the Basic Properties window for satellites allows you to
specify the event that defines the boundary between passes (or revolutions)
of an orbiting satellite.
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Pass breaks can be defined as the time that the satellite crosses a specified
latitude boundary in either the ECF or ECI coordinate system. You can
define the pass break by choosing the direction of motion (Ascending or
Descending) when the satellite crosses the specified latitude. The default
definition of the pass break is a 0º latitude in the inertial system on the
ascending side of the orbit (the ascending node). The pass (or revolution)
definition is a convention that satellite systems use to describe various
periodic data.
If the specified latitude crossing is outside of the satellite’s range of motion, the north point
or south point of the orbit is used as the pass break for specified positive or negative
latitudes.
Due to the precessional and nutational motion of the Earth’s spin axis, the crossing of the
ascending node may occur at a time slightly different from the time when the satellite
crosses the Earth-fixed equator.
Table 6-18. Pass Break fields
Field
Description
Direction
Specify either Descending (going south) or Ascending (going
north) for the latitude crossing at the beginning of a pass.
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Satellites
Field
Description
Coordinate
System
Specify either an Inertial or Earth-Centered Fixed coordinate
system in which the latitude should be measured.
Latitude
The latitude crossing at which a new pass will begin.
First Pass #
The pass number corresponding to the initial conditions of the
satellite.
Basic Properties: Mass
In the Mass tab of the Basic Properties window for satellites, you can specify
the satellite’s moment of inertia tensor and its mass.
Specify the satellite’s moments of inertia. The rows and columns in this
matrix are ordered to correspond to the X, Y and Z body-fixed axes
respectively.
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Graphics Properties: Attributes
The Attributes tab allows you to specify several aspects used to represent your
satellite in the Map window.
Table 6-19. Options in the Attributes tab
Field
Description
Color
The color of your satellite’s marker and tracks in the Map
window.
Line Style
The type of line used to represent your satellite’s path. Choices
are Long Dash, Solid, Dashed, Dotted, or Dot Dash.
Line Width
The width of the satellite path, in pixels, in the Map window.
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Field
Description
Marker Style
The type of marker used to represent your satellite’s current
position. Choices include Square, Point, Plus Sign, Star, Circle, or
an X, in addition to pictures from STK object icons and other
graphical images. You can also add a custom marker by creating a
pixmap file with a .marker extension and saving it to your
<Home>/stkData/Pixmaps directory. pixmaps can be any
size. Once created, custom markers are available in the Marker
Style list.
Inherit Settings
If the Inherit Settings feature is ON, the satellite’s label, ground
track, pass label and orbit track are displayed in accordance with
the scenario’s graphic attributes, set through the Attributes tab of
the scenario’s Graphic Properties window. If this feature is
OFF, the options available in this field override those set at the
scenario level. The Show Pass Labels setting doesn’t appear when
the satellite is defined as a rocket, regardless of whether Inherit
Settings are ON or OFF. The Show Elset Numbers option
appears only if satellite was propagated with the MSGP4
propagator.
Graphics Properties: Pass
The fields in this tab allow you to control the display of satellite pass graphics
in the Map window.
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Table 6-20. Options in the Pass tab
Field
Description
Show All
If ON, the entire ground track for the satellite is displayed in the
Map window. You must enable either Show All or Show Pass
From/To. To hide all satellite pass graphics, turn OFF the Inherit
Settings option then turn OFF the ground track on the satellite’s
Attributes tab.
Show Pass
From/To
If ON, the portion of the ground track within the specified
range displays in the Map window. Enter the beginning and end
pass numbers.
Visible Sides
Choose to display the entire pass, only the ascending side, or
only the descending side in the Map window. Also applies to the
display of satellite swaths and access as well as animation
graphics.
Leading/Trailing
Ground Track
Choose to display the satellite’s lead and trail ground tracks in
terms of a specified time (in seconds), a percentage, a quarter, a
half, full, all, none, or one pass only. The leading and trailing
portions of the ground track are determined based on the
current animation time.
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Field
Description
Leading/Trailing
Orbit Track
Orbit tracks are only visible when the Perspective Map
Projection is selected.
Graphics Properties: Display Times
The fields in this tab allow you to control the time periods when the satellite
graphics are displayed in the Map window.
Satellite graphics can be displayed or removed from the Map window based
on time intervals specified here. Choose among Use Intervals, Always On, or
Always Off. If you choose the Use Intervals option, the Start and Stop Times
specified in the list box are used as the time intervals during which satellite
graphics display in the Map window. If you choose the Always On option,
satellite graphics always display in the Map window, regardless of the
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intervals specified in the list box. If you choose the Always Off option,
satellite graphics never display in the Map window.
To specify the times during which satellite graphics should display in the
Map window, use the Add button. To modify a time interval in the list box,
highlight the time period of interest and use the Change button. To remove a
time period, use the Remove button.
You can also choose whether the time intervals should be “deconflicted,” or
modified so that time periods don’t overlap. If the Deconflict option is set to
Automatic, STK automatically modifies all time intervals during which an
overlap occurs so that the intervals are further segmented to avoid overlap. If
the option is set to None, no changes are made to time interval overlaps. If
the option is set to Manual, when an overlap occurs in the time interval list,
an Acknowledge window appears when you click the OK or Apply button to
alert you to the fact that overlap(s) exists. It is then your decision whether to
set the Deconflict field to Automatic so that overlap(s) are fixed, change the
time intervals yourself by modifying the appropriate entries in the list box, or
ignore the message and continue.
The time intervals only apply to the graphical display of the satellite—they don’t affect
access computations.
1RWH
Graphics Properties: Contours
The fields in this tab allow you to control the display of elevation angle
contours in the Map window.
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Contour levels represent the various regions of the surface that can see the
satellite at the specified elevation angle (refer to Level Adding to set the
elevation angles to be represented). If the Show Elevation Angle Contours
option is ON, contour graphics display in the Map window. If it is OFF,
contour graphics are removed from the Map window.
Level Adding
Choose either Start, Stop, Step or Explicit add method.
6-46
♦
Start, Stop, Step Method - Enter a Start contour value, a Stop value, and a
Step value. Use the Add button to generate contour values beginning with
the Start value and incrementing by the Step until the Stop value is
exceeded.
♦
Explicit - Enter individual contour values. Use the Add button to add the
new contour value to the list of existing contour values.
Satellite Tool Kit® User’s Manual
Satellites
Level Attributes
Each contour value has a color attribute that can be modified individually.
You can remove contour values from the list by highlighting the level(s) of
choice and using the Remove or Remove All buttons.
Constraints: Basic
The fields in this tab allow you to impose standard constraints for the
satellite.
Azimuth and Elevation Rates aren't available constraints for satellites.
1RWH
Satellite Tool Kit® User’s Manual
6-47
Satellites
1RWH
Abbreviations in the Contraints apply to column are as follows: F = facility, T = target, V =
all vehicles, S = satellite, M = missile, L = launch vehicle, G = ground vehicle, A = aircraft, B
= ship, N = sensor, P = planet, * = star, R = area target.
Table 6-21. Satellite basic constraints
Fields
Description
Constraint
applies to…
Min/Max Azimuth
Angle
Azimuth is measured in the plane
perpendicular to nadir from the projection of
the inertial velocity vector to the projection of
the relative position vector. This angle is
measured in a positive manner according to the
right-hand rule about the nadir vector. An
azimuth of 0° specifies a location directly in
front of the satellite and an azimuth of 180°
specifies a location directly behind the satellite.
F, T, R, P, *, V
Min/Max
Elevation Angle
Elevation is measured as the angle between the
nadir vector and the relative position vector
minus 90°. The elevation angle is positive for
objects above the plane perpendicular to nadir.
F, T, R, P, *, V
A drawing illustrating the elevation angle is
provided in Figure 6-2.
6-48
Min/Max Range
The range is measured as the distance between
the two objects.
F, T, V
Min/Max Range
Rate
Range rate is the component of the relative
velocity along the line of sight of the two
objects.
F, T, V
Min/Max Angular
Rate
The angular rate is the rotational rate of one
object, which is necessary to keep a fixed
vector in that object’s body-fixed coordinate
system aligned with the line of sight between
the two objects.
F, T, R, P, *, V
Satellite Tool Kit® User’s Manual
Satellites
Fields
Description
Constraint
applies to…
Line of Sight
If ON, access to the satellite is constrained to a
line of sight not obstructed by the Earth.
P, *, V
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If ON, access to the satellite is constrained by
the time it takes the signal to travel between
the two objects.
Propagation
Delay
F, T, V
Figure 6-2. Satellite elevation angle constraint
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Satellite Tool Kit® User’s Manual
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6-49
Satellites
Constraints: Sun
The fields in this tab allow you to impose constraints based on the position of the
Sun.
6-50
Satellite Tool Kit® User’s Manual
Satellites
Table 6-22. Satellite Sun constraints
Fields
Description
Constraint
applies to…
Sun
Elevation
Angle
The elevation angle to the apparent position of the Sun.
F, T, R, P, *, V
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Elev Angle
Measured with respect to targets or facilities. The
elevation angle, relative to the target or facility, to the
apparent position of the Sun.
F, T
Lunar Elev
Angle
Elevation angle to the apparent position of the Moon.
F, T, R, P, *, V
Solar
Exclusion
Angle
The minimum angle between the line of sight from
the source object to the object of interest and the line
of sight from the source object to the Sun for which
access is considered valid. For example, enter 5° in the
if you wish to ignore access to another object if it is
within 5° of the Sun (exclusion angle is 5°).
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The minimum angle between the line of sight from
Satellite Tool Kit® User’s Manual
F, T, R, P, *, V
6-51
Satellites
Fields
Description
Constraint
applies to…
Exclusion
Angle
the source object to the source object of interest and
the line of sight from the object to the Moon for
which access is considered valid.
Lighting
Indicates that access is valid under the specified
condition.
♦
Direct Sun (total Sunlight)
♦
Penumbra or Direct Sun (partial or total
Sunlight)
♦
Penumbra (partial Sunlight)
♦
Penumbra or Umbra (partial Sunlight or
total shadow)
♦
Umbra (total shadow)
♦
Umbra or Direct Sun (total shadow or total
Sunlight)
F, T, R, P, *, V
Full Sunlight
Penumbra
Umbra
Annular Eclipse
Penumbra
Full Sunlight
Solar/Lunar
Obstruction
Only applies when calculating access to a star or
planet. Obstruction occurs when access is blocked by
the Sun or Moon.
P, *
Constraints: Temporal
The fields in this tab allow you to impose time-based constraints on the
satellite.
6-52
Satellite Tool Kit® User’s Manual
Satellites
Table 6-23. Satellite temporal constraints
Fields
Description
Constraint
applies to…
Local
Start and end local time constraints. The satellite
local time is computed based upon the GMT of
interest and the longitude of the satellite at that
time. For every degree of east longitude, four
minutes are added to GMT to yield the satellite
local time.
F, T, R, P, *, V
GMT
Start and end GMT time constraints.
F, T, R, P, *, V
Local Apparent
Start and end local apparent times. Using local
apparent time, at noon the Sun is at the highest
elevation. Also known as Local Satellite Time
(LST).
F, T, R, P, *, V
Duration
Minimum and maximum acceptable durations
for computed accesses. If accesses whose
durations are outside these limits are computed,
they are discarded from the resultant list.
F, T, R, P, *, V
Satellite Tool Kit® User’s Manual
6-53
Satellites
Constraints: Advanced
The fields in this tab allow you to impose a variety of satellite-specific
constraints, such as grazing angle, solar beta angle, grazing altitude, etc.
6-54
Satellite Tool Kit® User’s Manual
Satellites
Table 6-24. Satellite advanced constraints
Fields
Description
Constraint
applies to…
Min/Max Grazing
Angle
Describes how high one object appears above
the edge of the Earth (or limb) relative to the
satellite. Measured relative to the satellite, as the
angle between the Earth limb and the other
object. This constraint can be used to prevent a
sensitive optical sensor, such as those on the
Hubble Space Telescope, from getting too close
to the Earth, which might blind the sensor due
to reflections off the surface.
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Min/Max Altitude
Specify the altitude range for which you wish to
limit access to the satellite.
F, T, R, P, *, V
Min/Max Solar
Beta Angle
The solar beta angle is the signed angle of the
vector to the Sun relative to the orbital plane.
The signed angle is positive when the vector to
the Sun is in the direction of the orbit normal.
The orbit normal is parallel to the orbital angular
momentum vector, which is defined as the
cross-product of the inertial position and
velocity vectors.
F, T, R, P, *, V
Satellite Tool Kit® User’s Manual
6-55
Satellites
Fields
Description
Constraint
applies to…
Min/Max Grazing
Altitude
The grazing altitude is defined by the closest
distance that the line of sight between the
satellite and the other object comes to the Earth.
This constraint can be used to prevent a
communications link between the two objects
from getting too far down into the atmosphere,
which might degrade the quality of the link.
P, *, V
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Background
Constrain access periods based on whether the
Earth is or is not in the background. This
constraint can be used to limit access from the
satellite to another vehicle.
V
♦
Space - Constrains accesses when
only space is in the background of the
other object
Ground - Constrains accesses
when only the ground is in the
background.
♦
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Min/Max Ground
Elevation Angle
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Measured with respect to targets or facilities.
The elevation angle is measured, relative to the
target or facility, as the angle between the local
horizontal and the direction of the satellite.
F, T
Satellite Tool Kit® User’s Manual
Satellites
Fields
Description
Constraint
applies to…
Ground Track
If ON, constrain access to the ascending or
descending side of the satellite’s ground track.
The ascending side of the ground track is
defined as the portions of the ground track
where the Earth-fixed latitude is increasing. The
Earth-fixed latitude decreases on the descending
side of the ground track.
F, T, R, P, *, V
Min/Max
Exclusion Zone
Specify the minimum and maximum latitude
and longitude at which access is to be
constrained. An exclusion zone is formed based
on the values entered. Refer to Figure 6-3.
F, T, R, P, *, V
Figure 6-3. Satellite exclusion zone constraint
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Satellite Tool Kit® User’s Manual
6-57
Satellites
127(6
6-58
Satellite Tool Kit® User’s Manual
7
SHIPS, AIRCRAFT &
GROUND
VEHICLES
Overview
This chapter describes nonorbiting vehicles, and provides instructions for setting
the basic and graphics properties as well as the access constraints of aircraft, ground
vehicles and ships. It also provides instructions for manipulating aircraft, ground
vehicles and ships to obtain the information you need for analysis and problemsolving.
Chapter Contents
Route ...........................................................................................................7-2
Attitude ........................................................................................................7-4
Satellite Tool Kit® User’s Manual
7-1
Ships, Aircraft & Ground Vehicles
External Attitude File ...............................................................................7-6
Graphics Properties: Attributes .....................................................................7-6
Graphics Properties: Display Times...............................................................7-8
Aircraft, Ground Vehicle & Ship Constraints.................................................7-9
Constraints: Advanced - Aircraft Only.........................................................7-10
Route
To define a route for your ship, aircraft or ground vehicle, open the Basic
Properties window for the object. In the Route tab, you can define the
trajectory which the object follows. At the top of this panel, the Start Time
and Stop Time fields specify the temporal boundaries of your aircraft, ground
vehicles and ships. The default values for Start Time and Stop Time are your
scenario start and stop times. The
Step Size field specifies the interval
between calculated ephemeris output points. The default value is 60 seconds.
You can choose to use the Great Arc Propagator or an external file containing
route information. The Great Arc Propagator defines aircraft, ground vehicles
and ships that follow a point-by-point path over the surface of the Earth at a
given altitude. The waypoints specified represent a particular latitude,
longitude, altitude and speed along the path. Great Arc paths, each of which
lies in a plane that contains the center of the Earth, are used to connect the
waypoints.
7-2
Satellite Tool Kit® User’s Manual
Ships, Aircraft & Ground Vehicles
A waypoint is comprised of latitude, longitude, altitude, rate and, optionally,
turn radius data. To define a waypoint, enter data in the five individual text
boxes below the Waypoint Table that correspond to the columns of the table.
When you finish entering all the elements of a waypoint, use the Insert Point
button in the Edit Mode field so that the point appears in the Waypoint Table
located above the text boxes. Each row describes one waypoint in the path of
your aircraft, ground vehicles and ships.
After you enter the first waypoint, you can click anywhere in the Map window to add
waypoints (latitude/longitude values) in the Waypoint table. However, you must enter
altitude, rate and turn radius values using the keyboard.
1RWH
When specifying a great arc trajectory using the mouse, it is best to specify the altitude
and rate data on the first point before creating the second point so that the initial altitude
and rule information become the default for all additional points.
+LQW
Table 7-1. Great Arc propagator elements
Elements
Description
Latitude
The latitude of the waypoint.
Satellite Tool Kit® User’s Manual
7-3
Ships, Aircraft & Ground Vehicles
Elements
Description
Longitude
The longitude of a waypoint.
Altitude
The altitude of a waypoint. Changes in altitude take effect linearly
between two waypoints.
Rate
The velocity of the aircraft, ground vehicles and ships from the
current waypoint to the next. Rate changes take place immediately
at the waypoint.
Turn Radius
The curvature of the arc between the current waypoint and the
next. A smaller turn radius produces a sharper curve in the arc.
Use the Insert Point button to append or insert additional waypoints to the
table. Use the Modify Point option to change a highlighted waypoint with new
position values using the mouse or keyboard. You can repeat this process as
often as necessary, but you must have valid entries in order for each waypoint
for the path to be computed.
1RWH
The Insert Point button becomes a Modify Point button when you switch Edit Modes to
Change Current Item.
Use the Delete Point button to remove the selected waypoint from the
Waypoint table.
Turn the Update Map Graphics feature ON to display the ground track for
the route defined by the waypoints in the Map window as new waypoints are
entered and calculated.
Attitude
The Attitude tab of the Basic Properties window for aircraft, ground vehicles
and ships can be used to specify the orientation of the object.
7-4
Satellite Tool Kit® User’s Manual
Ships, Aircraft & Ground Vehicles
When an axis is constrained, that particular axis attempts to point to the desired location
as close as possible while still maintaining its proper relationship with the other axes
defined in the coordinate system. When an axis is aligned, that axis points directly to the
desired object, forcing the other axes to rotate accordingly.
1RWH
Table 7-2. Attitude types
Attitude Type
Description
ECI velocity alignment
with nadir constraint
The object’s X axis is aligned with the inertial velocity
direction and the Z axis is constrained in the direction of
nadir. The Constraint Offset angle can be used to modify the
body-fixed constraint vector. This angle is measured from
the Z axis direction in a right-handed direction about the X
axis (e.g., to constrain with the Y axis, set the offset to
+90°).
Satellite Tool Kit® User’s Manual
7-5
Ships, Aircraft & Ground Vehicles
+LQW
Attitude Type
Description
ECF velocity
alignment with radial
constraint
The object’s X axis is aligned with the Earth fixed velocity
direction and the Z axis is constrained in the direction
opposite to nadir. The Constraint Offset angle can be used to
modify the body-fixed constraint vector. This angle is
measured from the Z axis direction in a right-handed
direction about the X axis (e.g.., to constrain with the Y axis
set the offset to +90°). This attitude profile is commonly
used for aircraft and surface-based vehicles.
The ECF velocity alignment with radial constraint profile is most appropriate for surface
vehicles and aircraft.
Small animation time steps may be needed to properly visualize satellites with spinning
attitude profiles.
External Attitude File
You can use external attitude data by entering an attitude file containing
quaternions. Turn the Attitude File option ON and specify the attitude file to
use. If ON, the file overrides the default attitude profile during the time span
of the quaternions contained in the file. The external attitude file format is
descried in Appendix C of this manual.
Graphics Properties: Attributes
The Attributes tab allows you to specify several aspects used to represent the
aircraft, ground vehicle or ship in the Map window.
7-6
Satellite Tool Kit® User’s Manual
Ships, Aircraft & Ground Vehicles
Table 7-3. Options in the Attributes tab
Field
Description
Color
The color of the object’s marker and tracks in the Map window.
Line Style
The type of line used to represent the object’s route. Choices are
Long Dash, Solid, Dashed, Dotted, or Dot Dash.
Line Width
The width of the object’s route, in pixels, in the Map window.
Marker Style
The type of marker used to represent the object’s current position.
Choices are Square, Point, Plus Sign, Star, Circle, or an X.
You can also add a custom marker by creating a pixmap file with a
.marker extension and saving it to your <Home>/stkData/
Pixmaps directory. pixmaps can be any size. Once created, custom
markers are available in the Marker Style list.
Inherit Settings
If ON, the object’s label and trajectory are displayed in accordance
with the scenario’s graphics attributes, set through the Attributes
tab of the scenario’s Graphics Properties window. If OFF, the
options here override those set at the scenario level.
Satellite Tool Kit® User’s Manual
7-7
Ships, Aircraft & Ground Vehicles
Graphics Properties: Display Times
The fields in this tab allow you to control the time periods when the object’s
graphics are displayed in the Map window.
Aircraft, ground vehicle and ship graphics can be displayed or removed from
the Map window based on time intervals specified here. Choose among Use
Intervals, Always On, or Always Off. If you choose the Use Intervals option, the
Start and Stop Times specified in the list box are used as the time intervals
during which object graphics display in the Map window. If you choose the
Always On option, object graphics always display in the Map window,
regardless of the intervals specified in the list box. If you choose the Always
Off option, object graphics never display in the Map window.
To specify the times during which object graphics should display in the Map
window, use the Add button. To modify a time interval in the list box,
7-8
Satellite Tool Kit® User’s Manual
Ships, Aircraft & Ground Vehicles
highlight the time period of interest and use the Change button. To remove a
time period, use the Remove button.
You can also choose whether the time intervals should be “deconflicted,” or
modified so that time periods don’t overlap. If the Deconflict option is set to
Automatic, STK automatically modifies all time intervals during which an
overlap occurs so that the intervals are further segmented to avoid overlap. If
the option is set to None, no changes are made to time interval overlaps. If
the option is set to Manual, when an overlap occurs in the time interval list,
an Acknowledge window appears when you click the OK or Apply button to
alert you to the fact that overlap(s) exists. It is then your decision whether to
set the Deconflict field to Automatic so that overlap(s) are fixed, change the
time intervals yourself by modifying the appropriate entries in the list box, or
ignore the message and continue.
The time intervals only apply to the graphical display of the object—they don’t affect
access computations.
1RWH
Aircraft, Ground Vehicle & Ship
Constraints
The basic, Sun and temporal constraints that can be imposed on an aircraft,
ground vehicle or ship in STK are the same as those that can be applied to
satellites. Please refer to Chapter 6, Satellites, for a detailed summary of the
constraints available for all vehicles. There are no advanced constraints for
ground vehicles and ships.
Satellite Tool Kit® User’s Manual
7-9
Ships, Aircraft & Ground Vehicles
Constraints: Advanced - Aircraft Only
The fields in this tab allow you to impose a variety of aircraft-specific
constraints, such as grazing angle, solar beta angle, grazing altitude, etc.
1RWH
Abbreviations in the Constraints apply to column are as follows: F = facility, T = target, V =
all vehicles, S = satellite, M = missile, L = launch vehicle, G = ground vehicle, A = aircraft, B
= ship, N = sensor, P = planet, * = star, R = area target.
7-10
Satellite Tool Kit® User’s Manual
Ships, Aircraft & Ground Vehicles
Table 7-4. Aircraft advanced constraints
Fields
Description
Constraint
applies to…
Min/Max Grazing
Angle
Describes how high one satellite appears
above the edge of the Earth (or limb) relative
to the aircraft. Measured relative to the aircraft
as the angle between the Earth limb and the
other object. This constraint can be used to
prevent a sensitive optical sensor from getting
too close to the Earth, which might blind the
sensor due to reflections off the surface.
P, *, V
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Min/Max Altitude
Specify the altitude range for which you wish
to limit access to the aircraft.
F, T, R, P *
Min/Max Grazing
Altitude
The grazing altitude is defined by the closest
distance that the line of sight between the
aircraft and other object comes to the Earth.
This constraint can be used to prevent a
communications link between the two objects
from getting too far down into the
atmosphere, which might degrade the quality
of the link.
F, T
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Satellite Tool Kit® User’s Manual
7-11
Ships, Aircraft & Ground Vehicles
7-12
Fields
Description
Constraint
applies to…
Min/Max Ground
Elevation Angle
Measured with respect to targets or facilities.
The elevation angle is measured, relative to the
target or facility, as the angle between the local
horizontal and the direction of the aircraft.
F, T
Min/Max Exclusion
Zone
Specify the minimum and maximum latitude
and longitude at which access is to be
constrained. An exclusion zone is formed
based on the values entered. Refer to Figure 63.
F, T, R, P, *, V
Satellite Tool Kit® User’s Manual
8
LAUNCH
VEHICLES &
MISSILES
Overview
This chapter describes nonorbiting vehicles, and provides instructions for setting
the basic and graphics properties as well as the access constraints of vehicles. It also
provides instructions for manipulating vehicles to obtain the information you need
for analysis and problem-solving.
Chapter Contents
Basic Properties: Trajectory...........................................................................8-2
Simple Ascent Propagator (Launch Vehicles)..........................................8-2
Ballistic Propagator (Missiles) ...................................................................8-3
Satellite Tool Kit® User’s Manual
8-1
Launch Vehicles & Missiles
External Propagator ................................................................................8-5
Basic Properties: Attitude ..............................................................................8-6
External Attitude File ...............................................................................8-7
Graphics Properties: Attributes .....................................................................8-7
Graphics Properties: Display Times...............................................................8-9
Graphics Properties: Contours ...................................................................8-10
Level Adding.........................................................................................8-11
Level Attributes......................................................................................8-12
Launch Vehicle & Missile Constraints..........................................................8-12
Basic Properties: Trajectory
To define a trajectory for your launch vehicle or missile, open the Basic
Properties window for the object. In the Trajectory tab, you can define the
path which the object follows. At the top of this panel, the Start Time and Stop
Time fields specify the temporal boundaries of the object. The default values
for Start Time and Stop Time are your scenario start and stop times. The Step
Size field specifies the interval between calculated ephemeris output points.
The default value is 60 seconds.
Launch vehicles and missiles each have their own special propagator in
addition to the option of using external files to define their trajectories.
Simple Ascent Propagator (Launch
Vehicles)
The simple ascent propagator creates an ascent trajectory based on the launch
and insertion parameters supplied by the user. The trajectory is a simple
8-2
Satellite Tool Kit® User’s Manual
Launch Vehicles & Missiles
curve rising vertically from the launch pad that smoothly turns over to insert
with a zero flight path angle at the insertion point with the user-specified
velocity.
Table 8-1. Simple Ascent propagator elements
Elements
Description
Launch Location
(first 3 fields)
Select one of the following two combinations:
♦
Launch Geodetic Latitude, Launch Longitude and
Launch Altitude
♦
Launch Geocentric Latitude, Launch Longitude,
Launch Radius
STK links these elements in such a way that switching one of
them from geodetic to geocentric (or vice versa) changes the
other correspondingly. Longitude is not differentiated along
geodetic/geocentric lines.
Burnout Velocity
th
(4 field)
Specify the burnout velocity in the units selected at the scenario
level.
Burnout Location
(last 3 fields)
These elements are linked and only two combinations are valid.
/ Impact Longitude
♦
Impact Latitude-Geodetic
Impact Altitude.
♦
Impact Latitude-Geocentric / Impact Longitude /
Impact Radius
/
Impact Latitude can be geodetic or geocentric, but need not
agree in this respect with Launch Latitude.
Ballistic Propagator (Missiles)
The Ballistic Propagator defines vehicles following an elliptical path that begins
and ends at the Earth’s surface. The shape of the trajectory can be further
refined by specifying a fixed flight time, initial velocity or altitude.
Satellite Tool Kit® User’s Manual
8-3
Launch Vehicles & Missiles
Some orbital elements for the Ballistic propagator are linked together and only
certain combinations are valid.
1RWH
Only the Fixed Delta V option is valid for trajectories specified using impact elevation and
azimuth.
Table 8-2. Ballistic propagator elements
Elements
Description
Launch Location
(first 3 fields)
Select one of the following two combinations:
♦
Launch Geodetic Latitude, Launch Longitude and
Launch Altitude
♦
Launch Geocentric Latitude, Launch Longitude,
Launch Radius
STK links these elements in such a way that switching one of
them from geodetic to geocentric (or vice versa) changes the
other correspondingly. Longitude isn’t differentiated along
geodetic/geocentric lines.
8-4
Satellite Tool Kit® User’s Manual
Launch Vehicles & Missiles
Elements
Description
Flight Parameters
th
(4 field)
When you enter a value for one of these elements, the system
automatically calculates the other values. Flight parameters can
be specified in one of three ways:
Impact Location
(last 3 fields)
♦
Fixed Delta V - The instantaneous thrust to be applied
to the vehicle being launched. If you enter 0, the
minimum Delta V is computed for launch and impact
locations.
♦
Fixed Apogee Alt - The vehicle’s maximum altitude.
♦
Fixed Time of Flight - The duration of the vehicle’s
flight.
These elements are linked and only three combinations are valid.
♦
Impact Latitude-Geodetic / Impact Longitude / Impact
Altitude.
♦
Impact Latitude-Geocentric / Impact Longitude /
Impact Radius
♦
Impact Elevation / Impact Azimuth.
Impact Latitude can be geodetic or geocentric, but need not
agree in this respect with Launch Latitude.
You can also enter launch points using the mouse in the Map window.
+LQW
1RWH
External Propagator
This propagator allows you to read the ephemeris for a launch vehicle or
missile from a file. Turn ON the External Ephemeris File field, then specify the
file you wish to use.
Satellite Tool Kit® User’s Manual
8-5
Launch Vehicles & Missiles
Basic Properties: Attitude
The Attitude tab of the Basic Properties window for launch vehicles and
missiles can be used to specify the orientation of the object.
1RWH
When an axis is constrained, that particular axis attempts to point to the desired location
as close as possible while still maintaining its proper relationship with the other axes
defined in the coordinate system. When an axis is aligned, that axis points directly to the
desired object, forcing the other axes to rotate accordingly.
Table 8-3. Attitude types
8-6
Attitude Type
Description
ECI velocity
alignment with nadir
constraint
The object’s X axis is aligned with the inertial velocity
direction and the Z axis is constrained in the direction of
nadir. The Constraint Offset angle can be used to modify the
body-fixed constraint vector. This angle is measured from the
Z axis direction in a right-handed direction about the X axis
(e.g., to constrain with the Y axis, set the offset to +90°).
Satellite Tool Kit® User’s Manual
Launch Vehicles & Missiles
Attitude Type
Description
ECF velocity
alignment with radial
constraint
The object’s X axis is aligned with the Earth fixed velocity
direction and the Z axis is constrained in the direction
opposite to nadir. The Constraint Offset angle can be used to
modify the body-fixed constraint vector. This angle is
measured from the Z axis direction in a right-handed direction
about the X axis (e.g.., to constrain with the Y axis set the
offset to +90°). This attitude profile is commonly used for
aircraft and surface-based vehicles.
The ECF velocity alignment with radial constraint profile is most appropriate for surface
vehicles and aircraft.
+LQW
Small animation time steps may be needed to properly visualize satellites with spinning
attitude profiles.
External Attitude File
You can use external attitude data by entering an attitude file containing
quaternions. Turn the Attitude File option ON and specify the attitude file to
use. If ON, the file overrides the default attitude profile during the time span
of the quaternions contained in the file. The external attitude file format is
described in Appendix C of this manual.
Graphics Properties: Attributes
The Attributes tab allows you to specify several aspects used to represent the
launch vehicle or missile in the Map window.
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8-7
Launch Vehicles & Missiles
Table 8-4. Options in the Attributes tab
Field
Description
Color
The color of the object’s marker and tracks in the Map window.
Line Style
The type of line used to represent the object’s route. Choices are
Long Dash, Solid, Dashed, Dotted, or Dot Dash.
Line Width
The width of the object’s route, in pixels, in the Map window.
Marker Style
The type of marker used to represent the object’s current
position. Choices are Square, Point, Plus Sign, Star, Circle, or an X.
You can also add a custom marker by creating a pixmap file with a
.marker extension and saving it to your <Home>/stkData/
Pixmaps directory. pixmaps can be any size. Once created,
custom markers are available in the Marker Style list.
Inherit Settings
8-8
If ON, the object’s label and trajectory are displayed in
accordance with the scenario’s graphics attributes, set through the
Attributes tab of the scenario’s Graphics Properties window. If
OFF, the options here override those set at the scenario level.
Satellite Tool Kit® User’s Manual
Launch Vehicles & Missiles
Graphics Properties: Display Times
The fields in this tab allow you to control the time periods when the object’s
graphics are displayed in the Map window.
Launch vehicle and missile graphics can be displayed or removed from the
Map window based on time intervals specified here. Choose among Use
Intervals, Always On, or Always Off. If you choose the Use Intervals option, the
Start and Stop Times specified in the list box are used as the time intervals
during which object graphics display in the Map window. If you choose the
Always On option, object graphics always display in the Map window,
regardless of the intervals specified in the list box. If you choose the Always
Off option, object graphics never display in the Map window.
To specify the times during which object graphics should display in the Map
window, use the Add button. To modify a time interval in the list box,
Satellite Tool Kit® User’s Manual
8-9
Launch Vehicles & Missiles
highlight the time period of interest and use the Change button. To remove a
time period, use the Remove button.
You can also choose whether the time intervals should be “deconflicted,” or
modified so that time periods don’t overlap. If the Deconflict option is set to
Automatic, STK automatically modifies all time intervals during which an
overlap occurs so that the intervals are further segmented to avoid overlap. If
the option is set to None, no changes are made to time interval overlaps. If
the option is set to Manual, when an overlap occurs in the time interval list,
an Acknowledge window appears when you click the OK or Apply button to
alert you to the fact that overlap(s) exists. It is then your decision whether to
set the Deconflict field to Automatic so that overlap(s) are fixed, change the
time intervals yourself by modifying the appropriate entries in the list box, or
ignore the message and continue.
1RWH
The time intervals only apply to the graphical display of the object—they don’t affect
access computations.
Graphics Properties: Contours
The fields in this tab allow you to control the display of launch vehicle and
missile contours in the Map window.
8-10
Satellite Tool Kit® User’s Manual
Launch Vehicles & Missiles
If the Show Elevation Angle Contours option is ON, contour graphics
display in the Map window. Contour lines indicate the boundaries between
regions of the surface, which see the vehicle at different elevation angles. If it
is OFF, contour graphics are removed from the Map window.
Level Adding
Choose either Start, Stop, Step or Explicit add method.
♦
Start, Stop, Step Method - Enter a Start contour value, a Stop value, and a
Step value. Use the Add button to generate contour values beginning with
the Start value and incrementing by the Step until the Stop value is
exceeded.
♦
Explicit - Enter individual contour values. Use the Add button to add the
new contour value to the list of existing contour values.
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8-11
Launch Vehicles & Missiles
Level Attributes
Each contour value has a color attribute that can be modified individually.
You can remove contour values from the list by highlighting the level(s) of
choice and using the Remove or Remove All buttons.
STK maintains separate contour lists for each contour so that you can define
different values for each type and switch back and forth as desired.
Launch Vehicle & Missile Constraints
The constraints that can be imposed on a launch vehicle or missile in STK are
the same as those that can be applied to satellites. Please refer to Chapter 6,
Satellites, for a detailed summary of the constraints available for all vehicles.
8-12
Satellite Tool Kit® User’s Manual
9
FACILITIES &
TARGETS
Overview
Facilities are defined as nonmobile points on the Earth’s surface. Typically,
facilities mark the position of ground stations, launch sites, tracking stations,
etc. Targets are also objects that mark locations on the Earth’s surface; as
such they can be used to represent points of interest for sensor coverage,
locations of cities, etc. Although facilities and targets are managed separately
in STK, they are functionally identical and are addressed concurrently in this
chapter. The objects are separated within STK to help in your analysis tasks.
Chapter Contents
Basic Properties: Position ..............................................................................9-2
Geodetic Position....................................................................................9-3
Spherical Position ....................................................................................9-4
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9-1
Facilities & Targets
Cartesian Position....................................................................................9-4
Cylindrical Position ..................................................................................9-5
Geocentric Position.................................................................................9-5
Basic Properties: Az-El Mask ..........................................................................9-6
Graphics Properties: Attributes .....................................................................9-6
Graphics Properties: Az-El Mask....................................................................9-8
Graphics Properties: Display Times...............................................................9-9
Constraints: Basic .......................................................................................9-10
Constraints: Sun .........................................................................................9-13
Constraints: Temporal ................................................................................9-16
Basic Properties: Position
The fields in the Position tab allow you to specify the location of the facility
or target.
The fields available in the Position tab depend on the Position Type you
select. You can specify the facility’s or target’s position by entering the
9-2
Satellite Tool Kit® User’s Manual
Facilities & Targets
appropriate values in the fields of this tab or by clicking on the point at
which you wish to locate the object in the Map window.
The local time zone and corresponding time offset from GMT is computed
automatically based on time zones spanning 15° in longitude. To override the
local time zone for the facility or target, turn the Local Time Offset from GMT
option ON and enter the time offset. To specify a local time offset
corresponding to Eastern Standard Time, enter a value of -5.0 hours.
If the Use Terrain Information option is ON, Altitude is taken from the terrain
information specified in the Terrain tab of the scenario’s Basic Properties
window.
Geodetic Position
If you select Geodetic, the following fields are available:
Table 9-1. Geodetic facility/target options
Field
Description
Latitude
Measured in degrees from -90.0° to +90.0°. The geodetic latitude of
a point is the angle between the normal to the reference ellipsoid
and the equatorial plane.
Longitude
Measured in degrees from -360.0° to +360.0°. The longitude of a
point is the angle between the projection of the position vector in
the equatorial plane and the prime meridian. It is measured as
increasing in a counterclockwise sense when viewed from the north
pole.
Altitude
Specified as distance above or below the reference ellipsoid. Altitude
is measured along the normal to the surface of the ellipsoid.
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9-3
Facilities & Targets
Spherical Position
If you select Spherical, the following fields are available:
Table 9-2. Spherical facility/target options
Field
Description
Latitude
Measured in degrees from -90.0° to +90.0°. The spherical latitude is
the angle of the position vector above the equatorial plane.
Longitude
Measured in degrees from -360.0° to +360.0°. The longitude of a
point is the angle between the projection of the position vector in
the equatorial plane and the prime meridian. It is measured as
increasing in a counterclockwise sense when viewed from the north
pole.
Radius
Distance of the object from the center of the Earth.
Cartesian Position
If you select Cartesian, the following fields are available:
Table 9-3. Cartesian facility/target options
9-4
Field
Description
X
The X component of the object’s position vector, where the X axis
crosses 0°/0° latitude/longitude.
Y
The Y component of the object’s position vector.
Z
The Z component of the object’s position vector, where the Z axis
points to the North pole.
Satellite Tool Kit® User’s Manual
Facilities & Targets
Cylindrical Position
If you select Cylindrical, the following fields are available:
Table 9-4. Cylindrical facility/target options
Field
Description
R
Enter the polar radius, where 5
Longitude
Enter the longitude measured in degrees from -360.0° to +360.0°.
The longitude of a point is the angle between the projection of the
position vector in the equatorial plane and the prime meridian. It is
measured as increasing in a counterclockwise sense when viewed
from the north pole.
Z
Enter the Z component of the object’s position vector.
= ;2 + <2
Geocentric Position
If you select Geocentric, the following fields are available:
Table 9-5. Geocentric facility/target options
Field
Description
Latitude
Measured in degrees from -90.0° to +90.0°. The geocentric latitude
of a point is the spherical latitude of the subpoint on the surface of
the central body.
Longitude
Measured in degrees from -360.0° to +360.0°. The longitude of a
point is the angle between the projection of the position vector in
the equatorial plane and the prime meridian. It is measured as
increasing in a counterclockwise sense when viewed from the north
pole.
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9-5
Facilities & Targets
Field
Description
Altitude
Specified above or below the reference ellipsoid. Altitude is
measured along the normal to the surface of the ellipsoid.
Basic Properties: Az-El Mask
PRO/
Terrain
In the Az-El Mask tab, specify the type of data to be used for the facility’s
azimuth, elevation and mask. If you choose Terrain, the data specified in the
Terrain tab of the scenario’s Basic Properties window. If you specify Az-El
Mask, enter the file name of the az-el mask file in the Mask field. The file
should be in the format detailed in Appendix C of this manual.
In the Height Adjustment option, specify the adjustment in height from the
Earth’s surface to the facility’s or target’s true height. This is useful for
positioning a specific sensor or point of interest.
Terrain data doesn’t include structures such as buildings.
1RWH
Refer to Appendix C for detailed information about file format requirements for importing
data into STK.
Graphics Properties: Attributes
The fields in the Attributes tab control the graphical display of the facility or
target in the Map window.
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Satellite Tool Kit® User’s Manual
Facilities & Targets
There are four fields in the Attributes window.
Table 9-6. Facility/target graphic attributes
Field
Description
Color
The color in which you wish your facility or target to appear.
Marker Style
Available options include square, circle, star, plus sign, point or an
X.
You can also add a custom marker by creating a pixmap file with a
.marker extension and saving it to your STK
<Home>/STKData/Pixmaps directory. Pixmaps can be any size.
Once created, custom markers are available in the Marker Style list.
Inherit Settings
If ON, the settings defined in the scenario’s Map Attributes tab are
used. If OFF, STK uses the settings specified here.
Show Label
Only available if the Inherit Settings feature is OFF. If the Show
Label option is ON, the facility or target label display in the Map
window. If OFF, the facility or target only appears as a marker and
no name appears.
Satellite Tool Kit® User’s Manual
9-7
Facilities & Targets
+LQW
It is best to use one marker style for a class of objects so that you can easily view
differences between one type of object and another. For instance, you may want to
always use the star marker style for a target and the square marker style for a facility for all
facilities in all scenarios.
Graphics Properties: Az-El Mask
The fields in the Az-El Mask tab control the display of azimuth and elevation
mask data in the Map window.
There are three fields available in the Azimuth-Elevation Mask tab.
Table 9-7. Facility/target azimuth-elevation mask graphics
9-8
Field
Description
Show Mask
If ON, the terrain mask is displayed in the Map window.
Satellite Tool Kit® User’s Manual
Facilities & Targets
Field
Description
Number of
Steps
Only valid if the Show Mask feature is ON. The Map window
shows the difference between the altitude range divided by the
number of steps specified. For instance, if you enter 2 steps with an
altitude range of 500 to 1500 nm, the Map window displays mask
constraints at 500 and 1500 nm.
Altitude Range
Only valid if the Show Mask feature is ON. Enter the altitude range
to display in the Map window for the facility or target.
Graphics Properties: Display Times
The fields in the Display Times tab allow you to control the display of
facility/target graphics in the Map window.
Facility and target graphics can be displayed or removed from the Map
window based on time intervals specified here. Choose among Use Intervals,
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9-9
Facilities & Targets
Always On, or Always Off. If you choose the Use Intervals option, the Start and
Stop Times specified in the list box are used as the time intervals during which
facility/target graphics display in the Map window. If you choose the Always
On option, facility/target graphics always display in the Map window,
regardless of the intervals specified in the list box. If you choose the Always
Off option, facility/target graphics never display in the Map window.
To specify the times during which facility/target graphics should display in
the Map window, enter the Start and Stop Times, then click on the Add button.
Use the Change button to modify a time interval. Use the Remove button to
remove a time period from the list.
You can also choose whether the time intervals should be “deconflicted,” or
modified so that time periods don’t overlap. If the Deconflict option is set to
Automatic, STK automatically modifies all time intervals during which an
overlap occurs so that the intervals are further segmented to avoid overlap. If
the option is set to None, no changes are made to time interval overlaps. If
the option is set to Manual, when an overlap occurs in the time interval list,
an Acknowledge window appears when you click on the OK or Apply button
to alert you to the fact that overlap(s) exists. It is then your decision whether
to set the Deconflict field to Automatic so that overlap(s) are fixed, change the
time intervals yourself by modifying the appropriate entries in the list box, or
ignore the message and continue.
Constraints: Basic
The fields in the Basic tab allow you to impose standard constraints for the
facility or target.
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Satellite Tool Kit® User’s Manual
Facilities & Targets
Abbreviations in the Constraints apply to column are as follows: F = facility, T = target, V =
all vehicles, S = satellite, M = missile, L = launch vehicle, G = ground vehicle, A = aircraft, B
= ship, N = sensor, P = planet, * = star, R = area target.
Table 9-8. Facility/target basic constraints
Fields
Description
Constraint
applies to…
Min/Max
Azimuth Angle
Azimuth is the angle between the relative
position vector and local north, measured
positive in an easterly direction from local north
in a plane tangent to the surface of the Earth at
the location of the facility or target. Using this
convention, local north is at 0° azimuth, local
east is at 90° azimuth.
All
Satellite Tool Kit® User’s Manual
9-11
1RWH
Facilities & Targets
Fields
Description
Constraint
applies to…
Min/Max
Elevation Angle
Elevation is the angle between the relative
position vector and the plane tangent to the
surface of the Earth at the location of the facility
or target. It is measured as positive in the
direction of the outward normal to the surface.
The horizon is at 0° and directly overhead in 90°
elevation. The angle should be visualized from
the perspective of the viewer (or facility/target)
as the angle at which the object being viewed
appears above the horizon.
All
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9-12
Min/Max
Range
Measured as the distance between the two
objects.
F, T, V
Min/Max
Azimuth Rate
The azimuth rate is the rate of change of the
azimuth angle.
All
Min/Max
Elevation Rate
The elevation rate is the rate of change of the
elevation angle.
All
Min/Max
Range Rate
The range rate is the component of the relative
velocity along the line of sight of the two
objects.
F, T, V
Min/Max
Angular Rate
The angular rate is the rotational rate of the
relative position vector measured in the
topocentric coordinate system.
All
Min/Max
Altitude
Refers to the Altitude of the other object in
access calculations.
All
Satellite Tool Kit® User’s Manual
Facilities & Targets
Fields
Description
Constraint
applies to…
Propagation
Delay
Enter the Minimum and/or Maximum light time
delay between the two objects. It is equivalent to
range divided by the speed of light.
F, T, V
Line of Sight
If ON, access to the facility or target is
constrained to a line of sight above the local
horizon. The default for this setting is ON.
F, T V, P
Az-El Mask
If ON, access to the object is constrained by
azimuth-dependent terrain masking. The terrain
mask used can come from terrain or a custom
Az-El Mask as defined in the basic properties of
the facility or target.
F, T V, P
The Line of Sight constraint should be turned OFF when the Az-El Mask constraint is used
to allow for az-el masks containing negative elevation angles.
Constraints: Sun
The fields in the Sun tab allow you to impose constraints based on the positions of
the Sun and Moon.
Satellite Tool Kit® User’s Manual
9-13
1RWH
Facilities & Targets
Table 9-9. Facility/target Sun constraints
Fields
Description
Constraints
apply to…
Sun Elevation
Angle
Elevation angle to the apparent position of the
Sun. Measured with respect to the facility or
target as the angle between the local horizon and
the apparent position of the Sun. The apparent
position of the Sun refers to the viewed position
of the Sun from the observer at a given time,
which takes into account the light time delay.
All
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Angle
9-14
Not available for facility/target constraints.
Satellite Tool Kit® User’s Manual
Facilities & Targets
Fields
Description
Constraints
apply to…
Lunar Elevation
Angle
Elevation angle to the apparent position of the
Moon.
All
Solar Exclusion
Angle
The minimum angle between the line of sight
from the source object to the object of interest
and the line of sight from the source object to the
Sun for which access is considered valid. For
example, enter 5° if you wish to ignore access to
another object if it is within 5° of the Sun
(exclusion angle is 5°).
All
The solar exclusion angle constraint defines a
zone of exclusion around the line of sight vector
to the Sun. The facility/target has access to
another object when the line of sight to the
object is outside of this exclusion zone.
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Lunar Exclusion
Angle
The minimum angle between the line of sight
from the source object to the object of interest
and the line of sight from the source object to the
Moon for which access is considered valid.
Satellite Tool Kit® User’s Manual
All
9-15
Facilities & Targets
Fields
Description
Constraints
apply to…
Lighting
Indicates that access is valid under the specified
condition. Select one of the following options:
All
Solar/Lunar
Obstruction
♦
Direct Sun (total sunlight)
♦
Penumbra or Direct Sun (partial or total
sunlight)
♦
Penumbra (partial sunlight)
♦
Penumbra or Umbra (partial sunlight or
total shadow)
♦
Umbra (total shadow)
♦
Umbra or Direct Sun (total shadow or
total sunlight)
Only applies when calculating access to a star or
planet. Obstruction occurs when access to the
star or planet is blocked by the Sun or Moon.
P, *
Constraints: Temporal
The fields in the Temporal tab allow you to impose time-based constraints on
the facility or target.
9-16
Satellite Tool Kit® User’s Manual
Facilities & Targets
Table 9-10. Facility/target temporal constraints
Fields
Description
Constraints
apply to…
Local
Start and end local time constraints. The local
time offset from GMT for facilities and targets is
set in the basic properties for the specified facility
or target.
All
GMT
Start and end GMT time constraints.
All
Local Apparent
Start and end local apparent times. Using local
apparent time, at noon the sun is at the highest
elevation.
All
Duration
Minimum and maximum acceptable durations for
computed accesses. If accesses whose durations
are outside these limits are computed, they are
discarded from the resultant list.
All
Satellite Tool Kit® User’s Manual
9-17
Facilities & Targets
127(6
9-18
Satellite Tool Kit® User’s Manual
10
AREA TARGETS
Overview
In some instances, you may need to define a target in terms of a geographical
area instead of a specific point location on the Earth’s surface. STK provides
you with this ability through the use of area targets, which are defined
separately from targets.
Chapter Contents
Basic Properties: Boundary.........................................................................10-2
Basic Properties: Centroid...........................................................................10-3
Geodetic Position..................................................................................10-4
Spherical Position ..................................................................................10-4
Cartesian Position..................................................................................10-5
Cylindrical Position ................................................................................10-5
Geocentric Position...............................................................................10-5
®
Satellite Tool Kit User’s Manual
10-1
PRO/
Advanced
Analysis
Area Target
Graphics Properties: Attributes ...................................................................10-6
Constraints: Basic .......................................................................................10-7
Constraints: Temporal ................................................................................10-9
Basic Properties: Boundary
The Boundary tab is used to define the area target’s perimeter.
:DUQLQJ
If you don’t specify a boundary with at least three points, the area target is not defined.
You can specify the position of perimeter points by entering the appropriate
values in the fields of this tab or by clicking on the point at which you wish
to locate the object in the Map window. If you define the area target by
clicking in the Map window, make sure that you click OK or Apply in the
Boundary tab to confirm the constructed boundary.
To position the area target using the fields in the Boundary tab, enter latitude
and longitude for each defining point in the boundary, then use the Insert
Point button. Repeat the procedure for the other perimeter latitude/longitude
values.
10-2
Satellite Tool Kit® User’s Manual
Area Target
Use the Change Current Point option and the Modify Point button to modify
an existing point in the list. Use the Delete Point button to remove a point
from the Boundary list.
Basic Properties: Centroid
The fields available in the Centroid tab allow you to set the area target’s
centroid position.
The fields available in the Centroid tab depend on the Position Type you
select. You can either set the position of the centroid manually by using the
fields displayed, or you can direct STK to calculate the centroid position
automatically by turning the Auto Compute Centroid option ON. If ON, only
the Altitude fields are available for input.
To define a local time for the area target, turn the Local Time Offset from GMT
optoin ON and enter the time offset. To enter a local time corresponding to
Eastern Standard Time, enter a value of -5.0 hours.
®
Satellite Tool Kit User’s Manual
10-3
Area Target
Geodetic Position
If you select Geodetic, the following fields are available:
Table 10-1. Geodetic area target fields
Field
Description
Latitude
Measured in degrees from -90.0° to +90.0°. The geodetic latitude
of a point is the angle between the normal to the reference ellipsoid
and the equatorial plane.
Longitude
Measured in degrees from -360.0° to +360.0°.
Altitude
Altitude values of the object above or below the reference ellipsoid.
Altitude is measured along the normal to the surface of the
ellipsoid, and is expressed in the scenario’s unit of measure for
distance.
Spherical Position
If you select Spherical, the following fields are available:
Table 10-2. Spherical area target options
10-4
Field
Description
Latitude
Measured in degrees from -90.0° to +90.0°. The spherical latitude is
the angle of the position vector above the X, Y (equatorial) plane.
Longitude
Measured in degrees from -360.0° to +360.0°.
Radius
The distance of the object from the center of the Earth.
Satellite Tool Kit® User’s Manual
Area Target
Cartesian Position
If you select Cartesian, the following fields are available:
Table 10-3. Cartesian area target options
Field
Description
X
The X component of the object’s position vector, where the X axis
crosses 0° latitude/0° longitude.
Y
The Y component of the object’s position vector.
Z
The Z component of the object’s position vector, where the Z axis
points to the North pole.
Cylindrical Position
If you select Cylindrical, the following fields are available:
Table 10-4. Cylindrical area target options
Field
Description
R
The polar radius, where
R=
x2 + y2
Longitude
The longitude measured in degrees from -360.0° to +360.0°.
Z
The Z component of the object’s position vector.
Geocentric Position
If you select Geocentric, the following fields are available:
®
Satellite Tool Kit User’s Manual
10-5
Area Target
Table 10-5. Geocentric area target options
Field
Description
Latitude
Measured in degrees from -90.0° to +90.0°. The geocentric latitude
of a point is the spherical latitude of the subpoint on the surface of
the central body.
Longitude
Measured in degrees from -360.0° to +360.0°. the geocentric
longitude of a point is the spherical longitude of the subpoint on the
surface of the central body.
Altitude
Enter altitude values of the object above or below the reference
ellipsoid. Altitude is measured along the normal to the surface of the
ellipsoid.
Graphics Properties: Attributes
The fields in the Attributes tab are used to specify the graphical display of the
area target in the Map window.
There are six fields in the Attributes window.
10-6
Satellite Tool Kit® User’s Manual
Area Target
Table 10-6. Area target atributes
Field
Description
Color
Select the color in which you wish the area target to appear in the
Map window.
Line Style
Choose among Solid, Long Dash, Dotted, Dot Dash or Dashed.
Marker Styles
Available options include square, circle, star, plus sign, point or an
X.
You can also add a custom marker by creating a pixmap file with a
.marker extension and saving it to your STK
<Home>/STKData/Pixmaps directory. Pixmaps can be any size.
Once created, custom markers are available in the Marker Style
options menu.
Line Width
1 = narrow, 5 = wide.
Inherit Settings
If ON, the inherit settings defined in the scenario’s Map
Attributes tab are used. If OFF, STK ignores the inherit settings
for the scenario.
Show Label
Only available if the Inherit Settings feature is turned OFF. If ON,
the area target label displays in the Map window.
Constraints: Basic
The fields in this tab allow you to impose standard constraints for the area
target.
®
Satellite Tool Kit User’s Manual
10-7
Area Target
The basic constraints for area targets apply to all points within the area
target. If the constraint is satisfied for at least one point, access to the area
target is considered valid. The planes tangent to the surface of the Earth
(local horizontal planes) are considered as unique for each point within the
area target.
1RWH
Abbreviations in the Constraints apply to column are as follows: F = facility, T = target, V =
all vehicles, S = satellite, M = missile, L = launch vehicle, G = ground vehicle, A = aircraft, B
= ship, N = sensor, P = planet, * = star, R = area target.
Table 10-7. Basic constraints for an area target
Field
Description
Constraint
applies to …
Minimum
Elevation Angle
Elevation is the angle between the relative
position vector from a point within the area
target to the object of interest and the local
horizontal plane at the point within the area
target.
F, T, R, P, *, V
Line of Sight
If ON (default), access to the area target is
constrained to when a line of sight is available
to some point in the area target above the
local horizon.
F, T, R, P, *, V
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Area Target
Constraints: Temporal
The fields in this tab allow you to impose time-based constraints on the area
target.
Table 10-8. Area target temporal options
Fields
Description
Constraint
applies to…
Local
Start and end local time constraints. The local time
offset from GMT for facilities and targets is set in
the basic properties for the specified facility or
target.
F, T, R, P, *, V
GMT
Start and end GMT time constraints.
F, T, R, P, *, V
Local
Apparent
Start and end local apparent times. Using local
apparent time, at noon the sun is at the highest
elevation.
F, T, R, P, *, V
Duration
Minimum and maximum acceptable durations for
computed accesses. If accesses whose durations are
outside these limits are computed, they are
discarded from the resultant list.
F, T, R, P, *, V
®
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Area Target
1RWH
Area targets are assumed to exist within a single time zone so that there is only one local
time offset from GMT. The local apparent time is computed based on the location of the
Centroid.
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11
STARS & PLANETS
Overview
STK provides you with the opportunity to conduct detailed analyses
involving numerous and varied objects in a scenario. Complex scenarios
often require the inclusion of stars and planets to provide a complete analysis
of sensor in-view opportunities. In STK, stars are used to represent
“stationary” objects such as stars, quasars and pulsars. Planets represent
objects in heliocentric orbit such as planets, minor planets, asteroids and
comets. For your convenience, the Moon and the Sun are also included in the
Planet class.
Chapter Contents
Basic Properties: Defining a Star .................................................................11-2
Basic Properties: Defining a Planet .............................................................11-3
Graphic Properties: Star/Planet Attributes...................................................11-4
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Stars & Planets
Basic Properties: Defining a Star
The Definition tab defines the position, proper motion and magnitude of a
star.
The fields in the Definition tab are described bin the table following.
Table 11-1. Star definition options
11-2
Field
Description
Position
The star’s position at the reference epoch of J2000.
♦
Right Ascension - The angle in the equatorial plane
measured in a right-handed rotation about the
inertial Z axis from the inertial X axis.
♦
Declination - The angle out of the inertial equator
measured towards the inertial positive Z axis.
Proper Motion
How the star moves relative to the solar system barycenter
expressed in arc seconds per year.
Magnitude
The visual brightness of the star. Currently, this field isn't
used.
Satellite Tool Kit® User’s Manual
Stars & Planets
Field
Description
Parallax
The apparent motion of the star due to changes in the Earth’s
position relative to the solar system barycenter.
Basic Properties: Defining a Planet
The Definition tab allows you to identify the ephemeris for a planet.
You can define ephemeris using Jet Propulsion Laboratory (JPL) DE403 file
shipped with STK or specify a file of your own that conforms to the external
planetary file format.
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Stars & Planets
Table 11-2. Planet definition elements
Field
Description
Ephemeris Source
Specify one:
Radius
♦
JPL DE403 -STK is shipped with a database of
ephemeris for each planet in our solar system plus
the Sun and Moon. Ephemerides, supplied by JPL,
cover a time span from 1960 to 2060.
♦
Analytic - Analytic representation of a planet’s state
as a reference of time.
♦
File - An external ephemeris file used to define the
planet.
1
Radius values update automatically when you choose a JPL
DE403 file.
Graphic Properties: Star/Planet
Attributes
The Attributes tab allows you to specify the graphical display of the star or
planet in the Map window.
1
James R. Wertz (ed.), Spacecraft Attitude Determination and Control,
Kluwer Academic Publishers, 1990, p. 816, Table L-2.
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Stars & Planets
There are four fields in the Attributes tab.
Table 11-3. Star/planet graphic attributes
Field
Description
Colors
The color in which you wish your star or planet to appear.
Marker Styles
Available options include square, circle, star, plus sign, point, or an X.
You can also add a custom marker by creating a pixmap file with a
.marker extension and saving it to your <Home>/stkData/
Pixmaps directory. Pixmaps can be any size. Once created, custom
markers are available in the Marker Style list.
Inherit Settings
If ON, the settings defined in the scenario’s Map Attributes tab are
used. If OFF, STK ignores the settings for the scenario.
Show Label
Only available if the Inherit Settings feature is turned OFF. If this
feature is ON, the star or planet label displays in the Map window. If
OFF, the star or planet only appears as a marker and no name
appears in the Map window.
It is best to use one marker style for a class of objects so that you can easily view
differences between one type of object and another. For instance, you may want to
always use the circle marker style for a star and the square marker style for a planet,
regardless of the scenario open.
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Stars & Planets
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12
SENSORS
Overview
Sensors and sensor performance are a major concern for satellite systems
engineers and integrators who analyze and design current and future systems.
In STK, the sensor’s field of view must be defined and its orientation relative
to its parent object must be specified.
Sensors can be used to represent such equipment as optical or radar sensors,
receiving or transmitting antennas, and lasers. They can also be used to define
another object’s field of view. Although sensors are objects, they are
subordinate to, or subobjects of, vehicles, targets or facilities.
When you change the properties of a sensor during an STK session, none of
the changes are saved to the sensor’s file until you save either the sensor itself
or the owner of the sensor (i.e., the facility, target or vehicle to which the
sensor is attached). For example, you can attach the same sensor to multiple
vehicles within a given scenario and make changes to individual sensors so
that they exhibit different characteristics during animation. If you save the
entire scenario, the properties of the last sensor saved define and overwrite
the properties of any like-named versions of that sensor.
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Sensors
Chapter Contents
Basic Properties: Definition .........................................................................12-2
Conic Sensor.........................................................................................12-3
Half-Power Sensor.................................................................................12-4
Custom Sensor......................................................................................12-6
Rectangular Sensor...............................................................................12-8
Basic Properties: Pointing a Sensor.............................................................12-9
Fixed Sensor Pointing .........................................................................12-10
Targeting a Sensor..............................................................................12-13
External Pointing Files .........................................................................12-16
Basic Properties: Resolution......................................................................12-16
Graphics Properties: Sensor Attributes......................................................12-17
Graphics Properties: Projection ................................................................12-18
Graphics Properties: Display Times...........................................................12-20
Constraints: Basic .....................................................................................12-21
Constraints: Sun .......................................................................................12-22
Constraints: Temporal ..............................................................................12-24
Constraints: Advanced .............................................................................12-24
Constraints: Resolution.............................................................................12-25
Basic Properties: Definition
You can define a sensor in any of the following ways: simple or complex
conic projection, half-power beam width or a custom pattern. The fields in
the Definition tab depend upon the type of sensor you choose.
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Sensors
Conic Sensor
If you select Conic, the following fields are available:
Table 12-1. Conic sensor options
Field
Description
Inner/Outer Half
Angles
The angular radius of the cone measured from the
boresight. For simple cones, enter only the outer cone value.
When an inner cone is specified, the inner region is
considered to be a region of exclusion.
Minimum/Maximum
Clock Angles
The range of rotation angle about the boresight relative to
the up vector. The clock corresponds to azimuth angles,
which are defined in the sensor pointing direction.
A diagram illustrating the structure of a conical sensor is presented in the
figure following.
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Sensors
Figure 12-1. Extended cone
Up Vector
Min. Clock Angle
Boresight
Min Clock Angle
Outer Angle
Max. Clock Angle
Max Clock Angle
Inner Angle
Cross Section
PRO/
Advanced
Analysis
3D View
Half-Power Sensor
Half-power sensors are specific to parabolic antennas.
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Sensors
The two-sided beam width of a half-power sensor is defined as follows:
λ
θ3dB = 70 
 D
 c 
= 70 
 fD 
where λ is equal to the wavelength (m), which is equal to the speed of
light (m/sec) divided by the frequency (Hz), and D is equal to the
diameter of the transmit antenna (m). The coefficient of illumination
is chosen to be 70.0°, which represents a nonuniform illumination. A
coefficient of 58.5° would represent a uniform illumination. The
resultant beam width is then divided by two to provide the effective
half-angle in STK.
Diameter values are always expressed in meters, regardless of the units of measure set at
the scenario level.
Table 12-2. Half-power sensor options
Field
Description
Frequency (GHz)
The antenna’s frequency in gigahertz.
Diameter
The diameter of the antenna dish.
Half Angle
Based on the values entered for Frequency and Diameter, STK
calculates the half angle of the cone for you. The computation
appears once you click Apply.
A diagram illustrating the structure of a half-power sensor is presented in the
following figure.
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Sensors
Figure 12-2 . Half-power cone
Half Angle
Half Angle =
Cross Section
21.0
2 x frequency (GHz) x Diameter (m)
3D View
Custom Sensor
If you select Custom, you can import your own sensor file or select the
Pattern Tool to create one.
PRO/
Advanced
Analysis
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Sensors
Pattern Tool
You can create a custom sensor pattern using the Pattern Tool button.
In the Time field, specify the time at which the settings are to apply, typically
to coincide with the passage of the satellite over a particular point on the
Earth. If the Show Boresight option is ON, the boresight is graphically
displayed in the Map window with a boxed X. If the Show Field of Regard
option is ON, the horizon of the sensor is outlined on the Map window.
You can specify the pattern of the sensor in one of three ways: Enter From
Area Target, Latitude/Longitude, or Azimuth/Elevation. Once you select an
option for the Point Type field, specify the perimeter points using the Point
Table and buttons in the lower portion of the window. If you define the
sensor pattern using the Enter From Area Target Point Type, enter the area
target’s file name.
To define the sensor pattern using the fields in the Custom Pattern window,
enter latitude and longitude or azimuth and elevation for each defining point,
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Sensors
then use the Insert Point button. Repeat the procedure for the other perimeter
values.
Use the Change Current Point option and the Modify Point button to modify
an existing point in the list. Use the Delete Point button to remove a point
from the Point list.
The following figure illustrates a custom pattern sensor shaped like an arrow.
Figure 12-3 . Custom pattern cone
Boresight
0 degrees
y
theta
90 degrees
x
radius
Cross Section
PRO/
Advanced
Analysis
3D View
Rectangular Sensor
The rectangle sensor type can be selected from among the options available
on the definition tab of the sensor Basic Properties window.
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Sensors
Enter the Verticle and Horizontal Half-Angles to define the retangular sensor
shape.
Basic Properties: Pointing a Sensor
The Pointing tab enables you to point or direct a sensor by describing the
sensor’s direction relative to the object it is a subobject of, or by selecting
one or more targets for the sensor. The fields available in the Pointing tab
depend on the Pointing Type you select.
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Sensors
Fixed Sensor Pointing
Orientation Method
The fields available in the Fixed field depend on the Orientation Method you select.
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Sensors
Table 12-3. Orientation methods
Orientation Method
Description
Az-El
To point a sensor relative to its parent object, enter the
azimuth and elevation of the boresight. These angles are
measured in the body-fixed coordinate system of the parent
object.
♦
Elevation - Defined as the angle between the
boresight vector and the body-fixed X,Y plane,
measured as positive in the direction of the bodyfixed -Z axis.
♦
Azimuth - Dependent upon the parent class (see
section immediately following).
♦
About Boresight - Choose between Hold and
Rotate (see the next table).
Quaternion
Specify the vector and scalar components of the
Quaternion.
Euler Angles
Specify Euler Angles A, B and C and select a Sequence of
Rotation.
YPR Angles
Specify Yaw, Pitch and Roll Angles.
The About Boresight field, which appears when you choose Az-El Orientation
Method, presents the following options:
Table 12-4. About Boresight settings
Setting
Description
Rotate
Rotation about the sensor’s Z axis, followed by rotation
about the new Y axis. In visual terms: rotates the sensor
pattern's general orientation about the boresight to maintain
a constant pattern relative to the earth while tracking the
target. In the Map window, the sensor projection remains
similarly shaped throughout the targeted access.
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Sensors
Setting
Description
Hold
Rotation about the Y axis followed by rotation about the
new X axis. In visual terms: holds a fixed orientation about
the boresight while tracking the target. This means that the
shape of the sensor pattern isn’t constant, and the access
calculations are different.
Facility/Target-Based Fixed Sensors
The definition of the Azimuth Angle is dependent upon the parent object
class. For facility- or target-based sensors, azimuth is measured from the
sensor “up” vector in a left-handed sense about the sensor boresight. For the
default elevation of 90°, the up vector points toward local north and azimuth
is measured as positive in an easterly direction. If the elevation is not 90° for
a facility-based sensor, the up vector is defined as:
Upx = sin (elevation) cos (azimuth)
Upy = sin (elevation) sin (azimuth)
Upz = cos (elevation)
where X, Y and Z are facility body-fixed coordinates (X points to local north,
Y points to local east, and Z points along the inward normal to the reference
ellipsoid).
Vehicle-Based Fixed Sensors
For a vehicle-based sensor (such as satellites, aircraft, ground vehicles, etc),
azimuth is measured from the sensor up vector in a right-handed sense about
the sensor boresight. For the default elevation of -90° and the default
attitude, the up vector points toward the projection of the Earth-fixed
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Sensors
velocity vector in the local horizontal plane and azimuth is measured as
positive in the direction off the right side of the vehicle. If the elevation isn’t
-90°, then the up vector is defined as:
Upx = -sin (elevation) cos (azimuth)
Upy = -sin (elevation) sin (azimuth)
Upz = -cos (elevation)
PRO/
Advanced
Analysis
Targeting a Sensor
To choose a sensor’s target(s), highlight the target you wish to select in the
Available Targets list and use the right arrow to copy it to the Assigned Targets
list.
You can remove a target from the Assigned Targets list by highlighting it in the list and
using the left arrow.
+LQW
You can define the sensor’s boresight capabilities as either: Tracking or Fixed.
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Sensors
Tracking Boresight
Select this option to aim a sensor at one or more targets (i.e., facility, vehicle
and/or target). The sensor’s footprint only appears on the map when a given
target is in view, as determined by the sensor constraints and the targeted
object’s constraints. As the sensor tracks a target, its footprint changes shape
until the target is no longer in sight. A targeted tracking sensor actually slews
or tracks its assigned targets as soon as one of its targets appears over the
horizon. No relative pointing is defined for this type of sensor.
Fixed Boresight
Select this option to point a sensor by providing azimuth and elevation values
for the sensor’s boresight. Since this is a targeted sensor, its footprint only
displays in the Map window when a target is in view. However, the sensor
always points in a fixed direction. The pointing of the sensor isn’t affected by
the target chosen. The sensor appears during animation only if one of the
assigned targets is visible within the defined view.
1RWH
The body-fixed -Z axis for a facility or target points toward zenith and for a vehicle is
attitude dependent. For the STK default attitude, with body-fixed +Z towards nadir,
positive elevation angles point sensors away from the Earth. The default elevation angles
are +90° for facility and target-based sensors and -90° for vehicle-based sensors.
Orientation Method
The orientation methods available for the Targeted Pointing Type are the same
as those for the Fixed Pointing Type, discussed on page 12-10.
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Sensors
Target Times
You can also specify the time during which the sensor points to the selected
target.
Use the access times determined between the vehicle and the selected target
by turning the Use Access Times option ON.
If you wish to select other times during which the vehicle should orient
toward a selected target, enter the Start and Stop Times, and use the Add
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Sensors
button. Use the Change button to modify an existing value. Use the Remove
button to remove a time period from the Scheduled Times list.
You can also choose whether the time intervals should be “deconflicted,” or
modified so that time periods set don’t overlap. If the Deconflict field is set to
Automatic, STK automatically modifies all time intervals during which an
overlap occurs so that the intervals are further segmented to avoid overlap. If
the field is set to None, no changes are made to time interval overlaps. If the
field is set to Manual, when an overlap occurs in the time interval list, an
Acknowledge window appears when you click the OK or Apply button to alert
you to the fact that the overlap exists. It is then your decision whether to set
the Deconflict field to Automatic so that the overlap is fixed, change the time
intervals yourself by modifying the appropriate entries in the list box, or
ignore the message and continue. The sensor target can be selected from the
list of assigned targets.
External Pointing Files
If you wish to use an external sensor file, select External as the Pointing Type,
then specify the correct the file name.
PRO/
Advanced
Analysis
Basic Properties: Resolution
The Resolution tab enables you to define the resolution of the sensor in
terms of focus and image quality.
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Sensors
In the Focus Constants field, enter the focal length and detector pitch of the
optical sensor. These constants are used in the computation of the Ground
Sample Distance (GSD) for the sensor. The GSD is computed as:
*6'
GHWHFWRU SLWFKUDQJH
IRFDO OHQJWK
VLQ HOHYDWLRQ
Graphics Properties: Sensor Attributes
The fields in the Attributes tab allow you to specify the graphical display of
the sensor in the Map window.
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Sensors
The fields available in the Attributes tab are described in the table
following.
Table 12-5. Sensor graphics attributes
Field
Description
Color
Choose the color in which you wish your sensor pattern to appear.
Line Style
Choose among Solid, Long Dash, Dotted, Dot Dash or Dashed.
Line Width
1 = narrow, 5 = wide.
Graphics Properties: Projection
The Projection tab is used to specify the display of sensor projection graphics
in the Map window.
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Sensors
It’s a good idea to select the maximum display altitude equal to the altitude of the vehicle
being observed to provide a proper graphical representation of the access area.
Sensors attached to facilities and targets differ in their display behavior from
those attached to vehicles. The intersections of vehicle-based sensors with
the Earth are displayed during animation. Nontargeted sensors attached to
facilities are only displayed if the Step Count is greater than 0. The Step Count
works in conjunction with the Minimum/Maximum Altitude fields to determine
the number and altitude of projections to be displayed. Each projection is
computed as the intersection of the sensor pattern with a sphere at the
requested radius. This intersection is then mapped back to the surface of the
Earth for display. For example, a sensor with Minimum/Maximum Altitude
settings of 500 km and 100 km and a Step Count of 3 would display
projections at altitude of 500 km, 750 km and 1000 km.
Persistence is the length of time the sensor’s footprint remains visible on the
Map during animation. It is used to display sensor footprints for a specified
period of time so that you can quickly and easily determine whether coverage
requirements are being met.
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+LQW
Sensors
In some cases, you may wish sensor projection graphics to display at the
altitude of a different object. To do this, turn the Track at Altitude option ON,
select the object of interest from the Available Objects list and use the right
arrow to copy it to the Assigned Object field.
Only one object can be selected for the Assigned Object.
1RWH
Graphics Properties: Display Times
The fields in this tab allow you to control the display of sensor graphics in
the Map window.
Sensor graphics can be displayed or removed from the Map window based on
time intervals specified here. Choose among Use Intervals, Always On, or
Always Off. If you choose the Use Intervals option, the Start and Stop Times
specified in the list box are used as the time intervals during which
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Sensors
facility/target graphics display in the Map window. If you choose the Always
On option, facility/target graphics always display in the Map window,
regardless of the intervals specified in the list box. If you choose the Always
Off option, facility/target graphics never display in the Map window.
To specify the times during which facility/target graphics should display in
the Map window, enter the Start and Stop Times, then use the Add button. Use
the Change button to modify a time interval in the list. Use the Remove
button to remove a time period from the list.
You can also choose whether the time intervals should be “deconflicted,” or
modified so that display time periods don’t overlap. If the Deconflict field is
set to Automatic, STK automatically modifies all time intervals during which
an overlap occurs so that the intervals are further segmented to avoid overlap.
If the field is set to None, no changes are made to time interval overlaps. If
the field is set to Manual, when an overlap occurs in the time interval list, an
Acknowledge window appears when you click the OK or Apply button to alert
you to the fact that the overlap exists. It is then your decision whether to set
the Deconflict field to Automatic so that the overlap is fixed, change the time
intervals yourself by modifying the appropriate entries in the list box, or
ignore the message and continue.
Constraints: Basic
The fields in this tab allow you to impose standard constraints for the sensor.
With the exception of the Field of View constraint, the definitions of all
constraints on this tab should be taken from the parent object of the sensor.
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Sensors
Constraints: Sun
With the exception of the Solar and Lunar Exclusion Angles, the definitions
of all constraints on this tab should be taken from the parent object of the
sensor.
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Abbreviations in the Contraints apply to column are as follows: F = facility, T = target, V =
all vehicles, S = satellite, M = missile, L = launch vehicle, G = ground vehicle, A = aircraft, B
= ship, N = sensor, P = planet, * = star, R = area target.
Table 12-6. Sensor Sun constraints
Fields
Description
Constraint
Applies to…
Solar Exclusion Angle
The minimum angle between the sensor
boresight and the line of sight from the
object to the Sun for which access is
considered valid. For example, enter 5° in
the text box if you wish to ignore accesses
where the boresight of the sensor is within
5° of the Sun (exclusion angle is 5°).
F, T, R, P, *, V
Lunar Exclusion
Angle
The minimum angle between the sensor
boresight and the line of sight from the
object to the Moon for which access is
considered valid.
F, T, R, P, *, V
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Sensors
Constraints: Temporal
The fields in this tab allow you to impose temporal constraints on the sensor.
The definition of all constraints on this tab should be taken from the parent
object of the sensor.
Constraints: Advanced
These constraints only apply to sensors on vehicles (such as satellites, ground
vehicles, ships, etc.); as a result, definitions of constraints on this tab should
be taken from the parent vehicle’s constraints properties.
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PRO/
Advanced
Analysis
Constraints: Resolution
Resolution constraints limit access based on sensor characteristics and the
quality of the inview.
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Sensors
Enter the minimum and maximum Ground Sample Distance in the units of
measure specified at the scenario level. The Ground Sample Distance is the
smallest size of an object on the ground that could be detected by the sensor.
It applies to facilities and targets. It is based upon the access geometry and
the physical attributes of the sensor as defined in the basic properties of the
sensor.
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13
USING STK TOOLS
Overview
To assist in satellite and systems analysis, STK offers various tools that can be
used to manipulate and display the data contained in individual objects. These
tools are separate from the properties of the object and include such
functions as calculating access between objects, computing lighting
conditions for an object, creating reports and graphs, using the satellite
database to import satellites, calculating a vehicle or sensor swath, and
generating a walker constellation. You can also remove accesses from all
objects in the scenario and show or hide the Map window.
STK tools are available through the Tools menu. Some of the tools can only
be used for certain objects. For instance, swath can only be used for vehicles
and sensors; it is grayed out in the pull-down menu if another object is
selected. For information about the objects in STK and their characteristics,
please refer to the appropriate chapter in this manual.
STK tools such as reports and graphs are discussed in separate chapters due
to their complexity. Please refer to Chapter 14 for information about the
four database tools (Satellite, City, Facility and Star) available in STK,
®
Satellite Tool Kit User’s Manual
13-1
Using STK Tools
Chapter 15 for Report and Graph tools, Chapter 16 for the Dynamic Display
and Strip Chart tools.
Chapter Contents
Access ........................................................................................................13-3
Calculating Access between Objects ....................................................13-3
Setting Access Graphics for the Map Window......................................13-5
Generating Access Reports ...................................................................13-6
Viewing Azimuth, Elevation and Range Data for Access ......................13-7
Using the Custom and Dynamic Display Options ................................13-8
Creating Graphs for Access Data ..........................................................13-8
Removing Accesses from the Map Window.........................................13-9
Accesses and Their Defining Objects ..................................................13-10
Lighting....................................................................................................13-11
Viewing the AER Report......................................................................13-13
Viewing a Time Data Report...............................................................13-13
Lifetime (Module) .....................................................................................13-14
Advanced ...........................................................................................13-17
Computing Lifetime ............................................................................13-19
Lifetime Results....................................................................................13-20
Report .................................................................................................13-21
Graph .................................................................................................13-22
Swath (Advanced Analysis Module).........................................................13-23
Vehicle Swath .....................................................................................13-23
Sensor Swath......................................................................................13-25
Walker Constellation ................................................................................13-26
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Using STK Tools
Remove Accesses................................................................................13-29
Close Approach Tool (Module) ................................................................13-29
Time Period.........................................................................................13-31
Access Constraint................................................................................13-31
Search Constraint................................................................................13-32
Advanced Options..............................................................................13-32
Computing Close Approaches............................................................13-34
Export Shapefile Tool................................................................................13-35
Change Icon Tool ....................................................................................13-35
Orbit Wizard.............................................................................................13-36
Access
STK allows you to determine the times one object can “access,” or see,
another object. In addition, you can impose constraints on accesses between
objects to define what constitutes a valid access. These constraints are
defined as properties of the objects between which accesses are being
calculated. STK can calculate access from vehicles, facilities, targets, area
targets, and sensors to all objects (including planets and stars) within the
scenario.
Calculating Access between Objects
To calculate accesses, highlight an object in the Browser window, select
Access from the Tools menu. An Access window appears.
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Make sure your time period is set to include ephemeris for both objects during access.
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It is best to check object constraints before performing access calculations.
Select the object for access determinations in the Associated Objects list, then
Compute. An asterisk () appears to the left of the object being accessed to
indicate that access calculations have been performed. If the Static Highlight
option is ON, the Map window updates to display access from the first
object to the second object based on time and object constraints defined.
Access between the two objects displays in bold. Objects for which accesses
have already been computed appear with asterisks () when the Access
window first displays.
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Figure 13-1. A typical Map window showing access between the ERS1
satellite and the Santiago facility.
Setting Access Graphics for the Map
Window
You can set graphics options for displaying accesses in the Map
window.
Table 13-1. Access graphics options
Field
Description
Show Line
If ON, a line appears on the Map between the two objects to show
when they are accessible to one another during animation.
Animate
Highlight
If ON, access is highlighted (displayed in bold print) during
animation. A box appears around each object during access.
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Field
Description
Static Highlight
If ON, access is highlighted in the Map window when the scenario
is not animating. This appears as a bold line on top of the ground
track for a vehicle or vehicle sensor and as an X for a facility, target
or attached sensor.
Generating Access Reports
Use the Access button in the Reports field to generate a report that provides
access times between the two objects selected.
To learn more about the commands available in the Access Summary Report window,
refer to Chapter 15 of this manual. STK is shipped with a number of standard report styles;
you can also customize a report to meet your requirements. For more information about
standard reports and instructions for customizing reports, refer to Chapter 15 of this
manual.
Figure 13-2. A sample Access Report showing access data for the ERS1
satellite to the Santiago facility
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Viewing Azimuth, Elevation and
Range Data for Access
Use the AER… button in the Reports field to view access data in terms of
AER.
Figure 13-3. A sample AER Report showing access data for ERS1 to the
Santiago facility.
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Azimuth and elevation values in the report are computed based on the local
coordinate system of the first object (object for which the Access window is
displayed). Data is displayed for the periods of valid access.
Using the Custom and Dynamic
Display Options
Custom reports and dynamic data displays can be quickly generated by
pressing the Custom… or Dynamic… Report buttons. These buttons display
dialogs described in Chapters 15 and 16 of this manual.
Creating Graphs for Access Data
To view access data in graph form, use the Access button the Graphs field.
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Figure 13-4. A sample Graph Data window showing access data for the
ERS1 satellite to the Santiago facility.
To learn more about the commands available in the Graph Data window, refer to the
Graphs section in Chapter 15 of this manual.
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You can zoom in for a closer look at the data points, change graph attributes,
or click a point of interest and determine the nearest data point.
Removing Accesses from the Map
Window
To clear the Map window of access graphics, use the Remove Accesses or
Remove All buttons in the Access window. When access to an object is
removed, the asterisk () to the left of its name in the tree disappears. If the remains, access data is still available.
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Accesses and Their Defining
Objects
An access is defined by the two objects for which the access is computed.
Once an access is created, it maintains a close relationship with the defining
objects. If either of the defining objects is changed in such a way that the
access times may be altered, the access is automatically recomputed. Also, if
either of the defining objects is removed from the scenario, the access is
automatically removed.
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The term target is used here to refer to any type of object in STK, not just an instance of
the Target class.
Access and targeted sensors have a special relationship. The “on” times for
the targeted sensor are computed based upon accesses between the sensor
and its assigned targets. These “on” times are automatically updated
whenever a targeted sensor or one of its targets are changed. The interaction
between a targeted sensor and another object that is not a target of the sensor
can be somewhat confusing if the targeted sensor has multiple targets
assigned to it.
If a targeted sensor could access multiple targets simultaneously, a projection
of the sensor to all accessible targets would be displayed during animation.
When accesses to a targeted sensor are computed, however, the pointing of
the sensor must be uniquely defined at each point in time. To accomplish
this, STK points the sensor to each accessible target until the end of that
target’s accessibility, starting with the first accessible target. A targeted
sensor may, therefore, point toward a particular target for part or none of its
accessible intervals, depending on the accesses to the other targets.
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Figure 13-5. Diagram showing access scheme for targeted sensors.
Target 1
Target 2
Target 3
2:00
1:00
12:00
3:00
4:00
5:00
6:00
Access Intervals
/HJHQG
Sensor Pointing
Nontargeted
Lighting
You can display lighting conditions for your vehicle in the Map window by
using the lighting tool. The lighting tool is only available for vehicles; its
menu item is disabled for other objects.
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The fields available in the Lighting window are discussed below.
Table 13-2. Lighting options
Field
Description
Sunlight
If ON, a line is drawn on the Map window(s) where the
vehicle is in complete sunlight.
Penumbra
If ON, a line is drawn on the Map window(s) where the
Sun is partially blocked by the Earth and, therefore, the
vehicle is only in partial sunlight.
Umbra
If ON, a line is drawn on the Map window(s) where the
Sun is completely blocked by the Earth and, therefore, the
vehicle isn’t in sunlight at all.
Show Sunlight/
Penumbra Line at
Vehicle Altitude
If ON, the Map window displays the dividing line between
sunlight and penumbra.
Show Penumbra/
Umbra Line at Vehicle
Altitude
If ON, the Map window displays the dividing line between
penumbra and umbra.
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Viewing the AER Report
To view lighting conditions in terms of AER, use the AER button. The report
shows azimuth, elevation and range data for the Sun relative to the object
selected. Values are computed based on the local coordinate system of the
vehicle.
To learn more about the commands available in the AER Report window, refer to the
Reports section in Chapter 15 of this manual.
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Figure 13-6. A sample AER Report showing lighting data for the Shuttle.
Other types of lighting AER data are available through the Reports option.
Viewing a Time Data Report
To view lighting times, use the Time Data button.
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Figure 13-7. A sample Lighting Times Report for the Shuttle.
This report shows the Start and Stop Times of the different lighting
conditions along with the obstructing body in the cases of Penumbra and
Umbra.
Lifetime (Module)
PRO/
Lifetime
The Lifetime tool estimates the amount of time a satellite can be expected to
remain in orbit before atmospheric drag and other perturbations cause it to
decay. Based upon algorithms developed at NASA's Langley Research
Center, Lifetime includes a highly accurate Jacchia 1970 atmosphere model to
compute drag effects between altitudes of 90 km and 2500 km, and a U.S.
Standard Atmosphere 1976 model for altitudes below 90 km. Lifetime also
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uses a simplified Earth gravitational model to enhance performance and
provide quicker results. Since the inclusion of higher order terms doesn't
significantly impact orbit decay estimates, the gravity model only considers
oblateness effects through J5. Lifetime also models the effects of solar and
lunar gravity and solar radiation pressure when computing perturbations to
the orbit.
Lifetime estimates the decay date of the satellite, the total lifetime from the
satellite's epoch and the number of orbits completed by the time of decay.
The orbital elements over the life of the satellite can also be shown in graph
and report formats.
Within Lifetime, only long-term changes to the satellite's orbit are considered;
short-period variations are assumed to average out and, therefore, aren’t
included in the calculations. As a result, Lifetime isn’t well suited for the
investigation of the short-term behavior of satellite orbits or perturbations to
the orbital elements over a single revolution. A satellite's orbit is allowed to
decay due to atmospheric and gravitational perturbations, with no
consideration given to propulsive thrust or changes in attitude that could
result in the addition of energy to the orbit.
Lifetime is currently limited to the analysis of Earth-orbiting satellites. Although there is no
upper limit to the altitude of a satellite that can be analyzed by Lifetime, the calculations
may not be sensitive enough to decay a satellite with a perigee altitude greater than 2500
km.
User inputs include the satellite's physical characteristics—mass, area, and
drag and reflection coefficients. In addition, solar flux and planetary
geomagnetic index information must also be supplied.
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The fields available in the Lifetime window are discussed in the table
following.
Table 13-3. Lifetime options
Option
Description
Drag Coefficient
The satellite's drag coefficient, usually taken to be between 2.0
and 2.2.
Reflection
Coefficient
The satellite's reflection coefficient, used in solar radiation
pressure calculations. A value of 0 indicates that the satellite is
transparent to solar radiation, a value of 1 indicates that it is
perfectly absorbing. A value of 4/3 means that it is flat,
specularly reflecting.
Drag Area
The mean cross-sectional area of the satellite perpendicular to
its direction of travel.
Area Exposed to
Sun
The satellite's mean area projected perpendicular to the Sun's
direction.
Mass
The mass of the satellite.
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Option
Description
Solar Data
An ASCII file containing predicted values of the monthly mean
10.7 cm solar radiation flux (F10.7) and geomagnetic index (Ap).
Refer to Appendix C for the format of this file.
Use the Solar Flux Data field to specify whether you want to
th
th
use Nominal (50 percentile) or +2σ (97.7 percentile) solar
flux and geomagnetic index data. Nominal flux predictions
represent an average case (longer lifetime); +2σ values represent
the worst case (shorter lifetime).
Graphics
If ON, the satellite’s final orbit displays in the Map window.
The ground track spans the length of the last orbit and is not
intended to represent the exact point of decay.
SGP4 Compute
The SGP4 theory estimates a satellite's orbital lifetime based on
USSPACECOM SGP4 general perturbations theory. It uses
the satellite's 2-line mean elements and, as such, doesn’t require
any of the inputs in either of Lifetime or Lifetime Advanced
windows. As a purely analytical solution, it doesn’t provide
time-histories of the orbital elements suitable for reports and
graphs. Use the SGP4 Compute button to compute the lifetime
based on this theory.
Advanced
Use the Advanced button to define the speed and accuracy of the calculations
to be performed when estimating a satellite’s orbital lifetime.
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The fields available in the Lifetime Advanced window are discussed in the
table following.
Table 13-4. Advanced options for Lifetime
Field
Description
Orbit Count Limit
The maximum number of orbits that will be analyzed before
the Lifetime tool stops processing. Setting this value to
999999 covers the whole lifetime for most satellites.
Orbits per Calculation
This parameter allows you to directly control the
performance of the Lifetime tool. The fewer orbits per
calculation, the more precise the lifetime estimate is, but at
the expense of compute time. The higher number of orbits
per calculation, the less precise the lifetime estimate will be,
but calculations are completed much faster. In general, set
this parameter to 10 for a quick estimate and 1 for the greatest
accuracy.
Gaussian
Quadratures
Like the previous parameter, this parameter directly affects
the performance of the Lifetime tool as well as the accuracy
of its results. The drag integration routine is performed by n
9-point Gaussian quadratures per orbit, where n is the
number set here. Set this parameter to at least 6 for increased
accuracy or lower it for increased speed.
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Field
Description
nd
Use 2 Order
Oblateness
Correction
Rotating Atmosphere
If ON, a second-order correction is included in the Earth
oblateness calculation. This correction is the J22 term, which
contributes as much to the gravitational potential as the J3, J4,
and J5 terms do.
If ON, the west-to-east winds induced by atmospheric
rotation are included in the perturbations to the orbit.
Computing Lifetime
Once the appropriate values have been set in the Lifetime and Advanced
windows, use the Compute button to start the lifetime calculations. How
long the Lifetime tool takes to estimate the satellite's lifetime depends
primarily on how high the satellite is at epoch and on the Orbits per
Calculation and Gaussian Quadratures parameters. A Progress window shows
the progress of the Lifetime tool and gives you the opportunity to cancel the
computations if necessary. The slider bar reaches 100% when the satellite
decays. The "percent of limit" progress message reaches 100% when the
number of orbits analyzed by Lifetime equals the Orbit Count Limit parameter
set in the Advanced window. If the "percent of limit" rapidly and
significantly outpaces the slider bar, you may want to cancel the
computations and increase the Orbit Count Limit. Otherwise, Lifetime will
probably reach the limit before the satellite actually decays.
Similarly, if the slider bar moves very slowly or if the time remaining steadily rises,
Lifetime may take a while to estimate the orbital lifetime of the satellite.
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For MSGP4 satellites, the orbital lifetime can be estimated by either the primary orbit
lifetime theory or the SGP4 analytical theory. The SGP4 theory estimates a satellite's orbital
lifetime based on USSPACECOM SGP4 general perturbations theory. It uses the satellite's 2line mean elements and, as such, doesn’t require any of the inputs in either of Lifetime or
Lifetime Advanced windows. As a purely analytical solution, it doesn’t provide timehistories of the orbital elements suitable for reports and graphs. Use the SGP4 Compute
button to compute the lifetime based on this theory.
If you want a quick estimate, cancel the calculations and adjust the Orbits Per
Calculation and/or Gaussian Quadratures fields in the Advanced window. Since the
integration of atmospheric drag effects is computationally expensive, reducing the
number of Gaussian Quadratures noticeably increases Lifetime's speed. Some
accuracy will be lost, but the difference in total lifetime for near- Earth satellites
should be small.
Increasing the Orbits Per Calculation parameter can also significantly increase
Lifetime's speed. When the number of Orbits per Calculation is greater than one,
Lifetime assumes that the perturbations to the satellite's orbit remain constant over the
number of orbits specified.
The Lifetime tool runs until either the satellite decays or the Orbit Count Limit is
reached. A satellite is assumed to decay when its height of perigee drops below 64 km.
Lifetime Results
As stated earlier, the Lifetime tool estimates the orbital lifetime of a satellite and
provides the corresponding date of decay. It should be emphasized that although the
Lifetime computations are based on sophisticated orbital theory and accurate
environment models, the result is still an estimate. Due to the seemingly random 10%
variation in atmospheric density and because of the difficulty in accurately predicting
solar activity, satellite lifetimes can’t be determined with an accuracy better than
+10% of the actual lifetime. Furthermore, assumptions and simplifications made in
order to produce a practical computer implementation of the lifetime theory
introduce an additional degree of uncertainty in the final result. The Lifetime tool is
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not intended to determine an exact time of decay, a specific geographical "impact
point," or to what degree a satellite might survive its descent through the atmosphere.
Report
Use the Report button to display a summary of the satellite's orbital elements
over the course of its lifetime. Each element is sampled at perigee passage;
thus, the mean, true and eccentric anomalies are always zero and aren’t
displayed.
Figure 13-8. Sample Lifetime report summarizing Keplerian elements
The results summarize perigee states only.
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Graph
Use the Graph button to graphically illustrate the satellite's orbital elements.
This is especially useful for observing trends and analyzing perturbations to
the elements. The changes which the elements undergo are quite complex,
especially toward the end of the satellite's life. Generally, though, as a satellite
decays you should expect to see the following effects:
♦
apogee altitude decreases while perigee altitude remains nearly constant
♦
the argument of perigee moves around the orbit plane to the point of
minimum atmospheric density
The satellite may be thought of as rotating its apse line and adjusting its
eccentricity so as to extend its life as long as possible.
Figure 13-9 . Sample Lifetime graph showing the evolution of the orbital
parameters height of apogee, height of perigee and inclination
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Swath (Advanced Analysis Module)
Most satellites, aircraft and other vehicles have on-board sensors for
observing or collecting data from areas on the Earth or equipment to
communicate to and from points on the ground or other vehicles. To assist
in the analysis of these sensor-vehicle systems, STK provides the ability to
draw lines on the Map that delineate the “visible” areas for the system, or
conversely, the points on the ground from which the vehicle can be seen.
PRO/
Advanced
Analysis
Vehicle Swath
The vehicle swath displays field-of-view swaths from nadir for a selected
ground elevation angle or for a half-angle relative to nadir or a surface
distance. The swath is always centered about the ground track and graphical
displays of the vehicle swath can be enhanced by cross-hatching, which
occurs at the vehicle data sample points.
The lines only apply to the left and right sides of the vehicle at a particular point in the
orbit, and not to the fore or aft of the vehicle.
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The fields available in the Swath window are discussed in the table
following.
Table 13-5. Vehicle swath options
Field
Description
Swath type
Choose among:
Options
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♦
Ground Elevation - Specifies the vehicle elevation
angle as measured from the ground to the vehicle.
For example, a 0° elevation angle would be the full
field of view from the vehicle’s perspective. The
easiest way to visualize this is from a ground-based
perspective. For a 1° elevation angle, an observer
standing on the swath limit looking toward the
vehicle would just see the vehicle above the
horizon. For a 45° angle, an observer would see the
vehicle “halfway up” in the sky; and for a 90° angle,
an observer would see the vehicle directly
overhead.
♦
Vehicle Half-Angle - Specifies the half-angle
relative to nadir. For example, for a 5° vehicle halfangle, the swath would be 10° in width, centered at
nadir.
♦
Swath Half - Specifies the swath limits as a
distance away from the subsatellite point as
measured along the surface of the central body.
Chose among:
♦
No Graphics - Removes the swath from the map
display.
♦
Edge Limits - Displays the swath limits to either
side of a center ground track.
♦
Filled Limits - Displays a crosstrack pattern to the
swath limits at each path point along the ground
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Sensor Swath
A sensor swath displays the area of coverage for the vehicle sensor. Swath
isn’t necessarily centered about the ground track. Sensor swaths can only be
generated for vehicles with nadir alignment with ECF velocity constraint
attitude.
The fields available in the Swath window are discussed below.
Table 13-6. Swath options
Field
Description
Color
The color in which you wish the swath graphics to appear.
Line/Marker Style
The type of line with which you wish the swath to display.
Line Width
1 = narrow, 5 = wide.
Start Time
The time at which you wish the sensor swath to appear.
Stop Time
The time at which you wish the sensor swath to disappear.
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Walker Constellation
A Walker constellation consists of a group of satellites (t) that are in circular
orbits and have the same period and inclination. The pattern of the
constellation consists of evenly spaced satellites (s) in each of the orbital
planes (p) specified so that t=sp. The ascending nodes of the orbital planes
are also evenly spaced over a range of right ascension (RAAN spread). The
relative along track position of two satellites in adjacent planes is determined
by a phase parameter (f) where f is an integer from 0 to p-1. The value of f
represents the number of slots of angular measure (360°/t) by which the
more easterly satellite leads the more westerly satellite.
STK makes it easy to generate a Walker constellation. First, define a vehicle
with the characteristics and orbit you need, then open the Walker tool for
that vehicle.
The fields available in the Walker window are:
Table 13-7. Options for a Walker constellation
Field
Description
Number of Planes
Enter the number of orbital planes to be used in the
constellation (p).
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Field
Description
Number of Sats per
Plane
Enter the number of satellites to be generated in each plane of
the constellation (s).
Inter-Plane Spacing
Enter the number of “slots” between the first vehicle in
adjacent planes (f).
RAAN Spread
Enter the number of degrees to be divided by the number of
planes to yield the difference in right ascension of the ascending
node between adjacent planes.
Color by Plane
If ON, all of the satellites within a single plane of the
constellation display in the same color in the Map window.
Remove
Constellation
Remove all of the child satellites associated with a Walker seed
satellite from your scenario. If you haven’t saved the
constellation before you remove it, the data is lost.
The RAAN spread is useful for small constellations in preventing undesirable
plane orientations. For example, if there were two orbit planes inclined at
90°, a RAAN spread of 180° would result in two perpendicular orbit planes
while a RAAN spread of 360° would result in all of the satellites being in the
same plane and in danger of head-on collisions.
To remove the Walker Constellation you must bring up the Walker window for the lead
satellite.
When a Walker constellation is created, the original (seed) satellite is
duplicated as part of the constellation. The new satellites are considered as
children of the seed. If you bring up a Walker window for a child satellite, all
fields are grayed out. In addition, the Number of Planes field and Number of
Satellites per Plane field shows the plane number and satellite number for the
selected child satellite.
For instance, if you defined a Walker constellation as having 2 Planes, 2
Satellites per Plane, an Interplane Spacing of 1 and a RAAN Spread of 360°, the
Map window would look similar to the one following.
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Figure 13-10. The Map window showing a Walker seed satellite and its
children (two planes each with two satellites).
The next figure more clearly shows the configuration and spacing of the
satellites.
Figure 13-11. Walker Constellation clearly illustrating the satellite
configuration.
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The table following describes the spacing between satellites in more detail.
Table 13-8. Satellite spacing for sample Walker satellites
Satellites
RAAN
Argument of Perigee
True Anomaly
Seed Satellite
0°
0°
0°
Satellite11
0°
0°
0°
Satellite12
0°
0°
180°
Satellite21
180°
0°
90°
Satellite22
180°
0°
270°
Remove Accesses
You can remove accesses from all objects in a scenario, regardless of the
objects involved. This is a scenario-level tool. This function is useful when
you calculated accesses between more than one pair of objects and wish to
clear all access graphics.
Close Approach Tool (Module)
CAT
Module
The Close Approach Tool (CAT) is a fully integrated module available for
STK that enables you to analyze and assess the potential for collision or close
proximity between a satellite and other objects in space. As the 1996 Cerise
collision demonstrated, analysis of space object proximities has become a
significant concern in mission analysis. Using CAT, you can search STK’s
Satellite Database of over 8,000 tracked space objects (specified by NORAD
two-line element sets) based on apogee, perigee and range tolerances. Once
you specify the range tolerance allowed between a specified satellite and
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other objects, CAT quickly analyzes the information against all objects in the
database.
Once these options are set, use the Compute button. CAT searches for
possible matches in the specified database based on the apogee, perigee and
range constraints set here as well as any apogee or perigee thresholds set in
the Advanced window. When CAT has prepared a preliminary list of
satellites for which the possibility of a close approach exists, it checks the
specified Time Period, then temporarily loads and propagates each of these
satellites over that time period. If accesses between a satellite on the
preliminary list and the current satellite are determined to be within the
specified range tolerance, the satellite(s) involved are inserted into the
current scenario and access graphics display in the Map window. If no
accesses are found, the satellites are removed from the scenario and a message
indicating that no matches were found displays in the Message window.
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Time Period
By default, the ephemeris start and stop time periods are entered in the Start
and Stop Time fields. You can change these values if necessary. If you enter
an incremental Start and Stop Time within the approved time period for the
satellite, then change the Start Time to a value that exceeds the current Stop
Time, the Stop Time is updated in the same increment as previously entered.
For example, if the Start Time is 1 Jan 1997 00:00:00.00 and the Stop Time
is 1 Jan 1997 01:00:00.00 and you change the Start Time to be 1 Jan 1997
02:00:00.00, CAT automatically changes the Stop Time to be 1 Jan 1997
03:00:00.00. If the Stop Time would be outside of the satellite’s Time Period,
CAT automatically adjusts the Stop Time to match the Stop Time of the
satellite.
You can’t set a Start or Stop Time outside of those set for the satellite’s ephemeris in the
satellite’s Basic Properties window. If you attempt to do so, an error message displays and
the changes are discarded.
Access Constraint
In the Max Range field, enter the maximum allowable distance between the
current object and any other object in the database. During analysis, when
CAT finds an object that is within the range specified in this field, the object
and the associated time is flagged and displayed. The Max Range Constraint is
automatically set for the satellite.
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Search Constraint
If you choose Auto, the Max Apogee and Min Perigee values are
automatically updated whenever the Time Period changes based on the
satellite’s minimum and maximum altitude for the time period. If you choose
Override, the Max Apogee and Min Perigee values are used, regardless of the
Time Period specified. These values are used to develop a preliminary list of
possible objects from the specified database that pass close to or through the
satellite’s orbit.
Advanced Options
Use the Advanced… button to specify the satellite database to be searched
and to set other limitations and graphics display parameters.
By default, CAT searches the stkAllTLE satellite database. To change the
database, enter the new database name and path in the File Name field.
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Search Tolerances
Because the apogee and perigee values of satellites included in the various
satellite database change over time, the Apogee and Perigee Threshold fields
are used to determine a valid range (plus or minus) for these values. The
Apogee value used in the search is equal to:
Search Apogee = A + AT + R
where A is apogee, AT is the apogee threshold and R is the range constraint.
The Perigee value used in the search is equal to:
Search Perigee = P - PT - R
where P is perigee, PT is the perigee threshold and R is the range constraint.
For instance, if you enter a value of 1000.0 km for both Apogee and Perigee
in the Close Approach window, then enter a value of 1.0 km for the Apogee
and Perigee Thresholds in the Close Approach Advanced window, CAT
would search for apogee and perigee values in the satellite database within +
1.0 km of the original satellite’s apogee and perigee value. Any Range
Constraint would be added to the total for the apogee and subtracted for the
perigee.
Launch Window
The Start and Stop Times for the time during which the satellite may be
launched can be specified in the Launch Window field. For these parameters
to be meaningful, the satellite should be defined using an external ephemeris
file that includes the satellite’s ascent profile.
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13-33
Using STK Tools
Access Graphics
You can also set Access Graphics to display in the Map window once results
have been tabulated. Choose to display Show Line, Animate Highlight and
Static Highlight.
Computing Close Approaches
When both standard and advanced parameters are set, use the Compute
button to determine the satellites that pass within the specified range during
the user-defined Time Period. While CAT is computing accesses, a Status
window appears.
1RWH
TLE files are considered to be out of date if they are more than 30 days old from the start
of the specified Time Period. However, all out-of-date TLEs are still included in the search
process.
When the calculations are complete, the Status window disappears and the
Message window displays showing the number of satellites that meet the
close approach parameters, if any, and the number of satellites that could
access the current satellite. Any warning messages, such as TLE files that are
out of date, are also displayed in the Message window.
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Satellite Tool Kit® User’s Manual
Using STK Tools
CAT adds the satellites meeting the search parameters to the Browser
window as objects in the scenario and displays accesses in the Map window.
Textual reports for each identified close approach can be generated using the
Reports option in the Access window.
Export Shapefile Tool
This tool enables you to export the shape data for a sensor or area target to
an ASCII file. In the case of a sensor, choose to export Swath or Pattern data.
Specify the file name.
Change Icon Tool
This tool (available on UNIX platforms) allows you to change the icon with
which a given object is represented in the object tree in the Browser window.
Highlight the object you wish to change and select Change Icon from the
Tools menu. In the Change Icon window, select the icon you wish to use and
click OK or Apply.
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13-35
Using STK Tools
Orbit Wizard
If you create a satellite in STK, an Orbit Wizard appears. The Wizard is
designed to assit you in creating any one of six standard orbits:
♦
Sun Synchronous - Orbit is designed to pass overhead at the same local
time each revolution.
♦
GeoStationary - Orbit is designed to remain over one point on the
ground.
♦
Repeating Ground Trace - Orbit is designed to provide a repeating
ground coverage cycle.
♦
Molniya - A highly elliptical orbit that is useful for communications over
the Northern hemisphere.
♦
Critically Inclined - Orbit is maintained at a fixed latitude.
♦
Critically Incclined Sun Synchronous - Orbit is maintained at a fixed
latitude and passes overhead at the same local time each revolution.
Once you’ve chosen the type of orbit youwish to create, the Wizard prompts
you to define the orbital parameters for the satellite. These parameters can
then be updated as needed in the Orbit tab.
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Satellite Tool Kit® User’s Manual
14
CITY, FACILITY,
SATELLITE & STAR
DATABASES
Overview
STK provides several tools that assist you in generating facilities, satellites,
targets and stars quickly and easily. Several comprehensive databases are
shipped with STK for your use. These databases include information about
thousands of facilities, cities, satellites and stars. Using the databases, you can
easily identify an object and insert it into the current scenario.
Chapter Contents
City Database.............................................................................................14-2
Querying a Database............................................................................14-3
®
Satellite Tool Kit User’s Manual
14-1
City, Facility, Satellite & Star Databases
Viewing Search Results .........................................................................14-4
Object Description................................................................................14-5
Facility Database ........................................................................................14-5
Querying a Database............................................................................14-6
Viewing Search Results .........................................................................14-7
Object Description................................................................................14-8
Satellite Database .......................................................................................14-8
Querying a Database..........................................................................14-10
Viewing Search Results .......................................................................14-11
Online Update....................................................................................14-12
Object Description..............................................................................14-14
Star Database...........................................................................................14-14
Querying a Database..........................................................................14-15
Viewing Search Results .......................................................................14-17
Object Description..............................................................................14-17
Load TLE ..................................................................................................14-18
Loading a Satellite TLE.........................................................................14-18
Loading a Facility TLE..........................................................................14-20
Object Description..............................................................................14-22
PRO/
Advanced
Analysis
City Database
Use the City Database tool to identify and insert cities as facilities or targets.
The city database contains thousands of cities around the world. Individual
city information includes exact location, population, etc.
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Satellite Tool Kit® User’s Manual
City, Facility, Satellite & Star Databases
Querying a Database
You can perform a city query using the default database shipped with STK or
you can identify a database of your own to use in the search. To change the
database set in the Database tab of the scenario’s Basic Properties window,
enter the correct file in the Database field. Once you’ve chosen the database,
enter as many search criteria as possible.
Use wildcard entries * and ? to assist in the search if you know only a portion of the
criteria. You can use the wildcards anywhere in the entry.
®
Satellite Tool Kit User’s Manual
+LQW
14-3
City, Facility, Satellite & Star Databases
Table 14-1. City Database options
Search Criteria
Description
City Name
Enter the name of the city for which you wish to search.
Province/State
Enter the name of the Province or State in which the city is
located.
Latitude: Min/Max
Enter the minimum and/or maximum search limits for
latitude.
Longitude: Min/Max
Enter the minimum and/or maximum search limits for
longitude.
Population: Min/Max
Enter the minimum and/or maximum search limits for
population.
Country
Specify the country in which the city is located.
City Type
Specify the type of city of interest. Choose among:
Populated Place, Administration Center, National Capital,
Territorial Capital.
When you’ve entered as many search criteria as possible, click the Perform
Search… button.
1RWH
The query assumes an implicit AND between search criteria. You cannot search for
EITHER/ OR parameters.
Viewing Search Results
Once you’ve queried the database, the City Database Search Results window
appears.
If there are a number of cities resulting from the search, select the items of
interest in the list. Use the Select All button to select all cities in the list. Use
the Deselect All button to deselect all of the selected cities in the list. Other
14-4
Satellite Tool Kit® User’s Manual
City, Facility, Satellite & Star Databases
options in the City Database Search Results window are described in the
table following.
Table 14-2. City Database search results options
Field
Description
Create Facility or
Target Class
Choose to insert the city as either a facility or target class.
Create Constellation
(Chains module only)
If ON, STK creates a constellation that includes all of the
cities you selected. Enter the constellation's name in the text
box.
When you’re satisfied, click the OK button to insert the selected items into
the current scenario. The Browser and Map windows are updated to display
the new cities as facilities or targets.
You can insert more than one city at a time. If several cities are highlighted, they are all
inserted.
+LQW
Object Description
If you load a facility or target using the City Database tool, the following
information is entered into the object's Long Description field.
PRO/
Advanced
Analysis
♦
City Name
♦
Type
♦
Latitude
♦
Province/State
♦
Country
♦
Province Rank
♦
Longitude
♦
Population
Facility Database
STK's Facility Database tool allows you to search for known facilities.
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City, Facility, Satellite & Star Databases
Querying a Database
You can perform a facility query using the default database shipped with STK
or you can identify a database of your own to use in the search. To change
the default database, enter the correct file in the Database field.
Once you’ve chosen the database, enter as many search criteria as possible.
+LQW
Use wildcard entries * and ? to assist in the search if you know only a portion of the
criteria. You can use the wildcards anywhere in the entry.
Table 14-3. Facility Database options
14-6
Search Criteria
Description
Site Name
Enter the name of the facility for which you wish to search.
Latitude: Min/Max
Enter the minimum and/or maximum search limits for latitude.
Satellite Tool Kit® User’s Manual
City, Facility, Satellite & Star Databases
Search Criteria
Description
Longitude:
Min/Max
Enter the minimum and/or maximum search limits for
longitude.
Altitude: Min/Max
Enter the minimum and/or maximum search limits for altitude.
Network
Specify the type of facility of interest, such as USAF.
When you’ve entered as many search criteria as possible, click the Perform
Search… button.
The query assumes an implicit AND between search criteria. You cannot search for
EITHER/ OR parameters.
1RWH
Viewing Search Results
Once you’ve queried the database, the Facility Database Search Results
window appears.
If there are a number of facilities resulting from the search, select the items
of interest in the list. Use the Select All button to select all cities in the list.
Use the Deselect All button to deselect all of the selected facilities in the list.
Other options in the Facility Database Search Results window are described
in the table following.
Table 14-4. Facility Database search results options
Field
Description
Create Facility or
Target Class
Choose to insert the facility as either a facility or target class.
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14-7
City, Facility, Satellite & Star Databases
Field
Description
Create
Constellation
(Chains module
only)
If ON, STK creates a constellation that includes all of the
facility you selected. Enter the constellation's name in the text
box.
When you’re satisfied, click the OK button to insert the selected items into
the current scenario. The Browser and Map windows are updated to display
the new facilities or targets.
+LQW
You can insert more than one facility at a time. If several facilities are highlighted, they are
all inserted.
Object Description
If you load a facility or target using the Facility Database tool, the
following information is entered into the object's Long Description
field.
♦
Site Name
♦
Network
♦
Latitude
♦
East Longitude
♦
Altitude
Satellite Database
The U.S. Space Command (USSPACECOM) currently keeps track of more
than 7000 orbiting objects. USSPACECOM continuously generates data
describing the orbits of these objects and makes it available through a variety
of sources. The data is in a form known as two-line element sets (TLE); each
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Satellite Tool Kit® User’s Manual
City, Facility, Satellite & Star Databases
set is 2 lines that are 69 characters wide. Three satellite databases
(stkSatDb.*, stkAllActive.*, stkAllComm.*, stkActiveTLE.*,
stkAllTLE.*, stkSatDbAll.*) were shipped with STK for your
convenience. If you have a TLE that you wish to use for defining a vehicle,
use the Satellite Database tool to load the data as a vehicle in your scenario.
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City, Facility, Satellite & Star Databases
Querying a Database
You can perform a satellite query using the default database shipped with
STK or you can identify a database of your own to use in the search. Enter
the correct file name in the Database field.
Once you’ve chosen the database, enter as many search criteria as
possible.
+LQW
Use wildcard entries * and ? to assist in the search if you know only a portion of the
criteria. For instance, if you enter INTELSAT* in the Name text box, query results would
include all satellites whose name begins with INTELSAT. You can use the wildcards
anywhere in the entry.
Table 14-5. Satellite Database options
Search Criteria
Description
SSC
The SSC number of the vehicle.
Common Name
The common name of the satellite.
Official Name
The official name of the satellite
International
Number
The international number of the vehicle. The international
number format is YYYY-DDD and an alpha indicator if
there is more than one part of the satellite.
Apogee: Min/Max
The minimum and/or maximum search limits for apogee.
Perigee: Min/Max
The minimum and/or maximum search limits for perigee.
Period: Min/Max
The minimum and/or maximum search limits for period.
Inclination: Min/Max
The minimum and/or maximum search limits for
inclination.
Owner
The country which owns the satellite.
Mission
The mission which the satellite performs.
Status
Choose either Active or Inactive.
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Satellite Tool Kit® User’s Manual
City, Facility, Satellite & Star Databases
When you’ve entered as many search criteria as possible, click the Perform
Search… button.
The satellite query assumes an implicit AND between search criteria. You cannot search for
EITHER/ OR parameters.
Viewing Search Results
Once you’ve queried the database, the Satellite Database Search Results
window appears.
If there are a number of satellites resulting from the search, select the
satellite(s) of interest in the list. Use the Select All button to select all satellites
in the list. Use the Deselect All button to deselect all of the selected satellites
in the list. Other options in the Satellite Database Search Results window are
described in the table following.
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1RWH
City, Facility, Satellite & Star Databases
To select more than one satellite, hold down the S key.
+LQW
Table 14-6. Satellite Database search results options
Field
Description
Auto Propagate
If ON, ephemeris is propagated using the scenario Time
Period (or the Time Period set here) and the MSGP4
Propagator.
Time Step
Specifies the interval calculated ephemeris output points.
Start/Stop Time
Specifies the temporal boundaries of the vehicle's orbit.
Create Constellation
(Chains module only)
If ON, STK creates a constellation that includes all of the
satellites you selected. Enter the constellation's name in the
text box.
When you’re satisfied, click the OK button to insert the vehicle(s) into the
current scenario. The Browser and Map windows are updated to display the
new satellite(s).
+LQW
You can insert more than one satellite at a time. If several satellites are highlighted, they
are all inserted.
Online Update
If you have internet access, you can obtain the most up-to-date Satellite
Database using the Online Update button.
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Satellite Tool Kit® User’s Manual
City, Facility, Satellite & Star Databases
Options available for online update are described in the table following
Table 14-7. Online Satellite Database update options
Field
Description
Update Option
Choose either:
Update Database
♦
Update Database - Obtain the latest satellite database
information available.
♦
Obtain Archived Database - Obtain an older version of
the database from the date specified in the Archive
Date field. If an update isn't available from the specified
date, STK displays a message indicating the date of the
closest archived database available and an option to use
that file.
Choose either:
♦
All Databases - Update all Satellite Databases available.
♦
Specific Database - Update only the database specified.
Database Directory
Specify the directory in which the database files are contained.
Archive Date
Specify the date of the archived database you wish to obtain.
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14-13
City, Facility, Satellite & Star Databases
When you finish, use the Go Online button to immediately begin
downloading the latest information.
Object Description
If you load a satellite using the Satellite Database tool, the following
information is entered into the vehicle’s Long Description field.
PRO/
Advanced
Analysis
♦
SSC Number
♦
Common Name
♦
Official Name
♦
International Number
♦
Owner
♦
Mission
♦
Launch Site
♦
Launch Date
♦
Launch Time
♦
Deorbit Date
♦
Launch Sequence
♦
Mass
♦
Apogee
♦
Perigee
♦
Period
♦
Inclination
♦
Status
♦
Write Up
Star Database
The Star Database tool allows you to identify and insert specific stars into the
current scenario. It contains tens of thousands of stars along with
information about star catalog numbers, magnitude, proper motion and
parallax.
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Satellite Tool Kit® User’s Manual
City, Facility, Satellite & Star Databases
Querying a Database
You can perform a star query using the default database shipped with STK or
you can identify a database of your own to use in the search. To change the
database, enter the correct file in the Database field.
Once you’ve chosen the database, enter as many search criteria as
possible.
Use wildcard entries * and ? to assist in the search if you know only a portion of the
criteria. You can use the wildcards anywhere in the entry.
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City, Facility, Satellite & Star Databases
Table 14-8. Star database options
Search Criteria
Description
Harvard Revised
Number
Used to identify stars in the Bright Star Catalogue (BSC),
which contains basic astronomical and astrophysical data
for stars brighter than magnitude 6.5.
Henry Draper
Number
Used to identify stars using the Henry Draper Catalogue,
which is a compilation of stellar spectra.
SAO Catalog Number
Used to identify stars using the Smithsonian Astrophysical
Observatory (SAO) catalog, which contains astrometric
(positional) data for stars to an approximate magnitude of
9.0.
th
5 Fundamental
Catalog
Used to identify stars using the Basic Fifth Fundamental
Catalog (FK5), which contains position and proper
motion data for stars of magnitude 7.0 or brighter. An
extension to FK5 is in progress; data for 1000+ stars of
magnitudes 5.0 to 7.0 and 2000 stars of magnitude 6.5 to
7.5 will be included.
Common Name
The common name of the star.
Visual Magnitude:
Min/Max
The minimum and/or maximum search limits for visual
magnitude.
Right Ascension:
Min/Max
The minimum and/or maximum search limits for right
ascension .
Declination: Min/Max
The minimum and/or maximum search limits for
declination.
Constellation Name:
Specify the name of the constellation in which the star is
located, such as Andromeda.
When you’ve entered as many search criteria as possible, click the Perform
Search… button.
1RWH
The query assumes an implicit AND between search criteria. You cannot search for
EITHER/ OR parameters.
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Satellite Tool Kit® User’s Manual
City, Facility, Satellite & Star Databases
Viewing Search Results
Once you’ve queried the database, the Star Database Search Results window
appears.
If there are a number of stars resulting from the search, select the items of
interest in the list. Use the Select All button to select all stars in the list. Use
the Deselect All button to deselect all of the selected stars in the list.
Other options in the Star Database Search Results window are described in
the table following.
Table 14-9. Star Database search results options
Field
Description
Create Constellation
(Chains module only)
If ON, STK creates a constellation that includes all of the
stars you selected. Enter the constellation's name in the text
box.
When you’re satisfied, click the OK button to insert the selected items into
the current scenario.
You can insert more than one star at a time. If several stars are highlighted, they are all
inserted when you click the OK button.
Object Description
If you load a star using the Star Database tool, the following information
is entered into the object's Long Description field.
♦
Harvard Revised Number
®
Satellite Tool Kit User’s Manual
♦
Henry Draper Number
SAO
Number
♦
Catalog
14-17
+LQW
City, Facility, Satellite & Star Databases
♦
5th Fundamental Catalog
♦
♦
Visual Magnitude
♦
♦
Parallax
♦
Right Ascension (J2000)
Proper
Ascension
Motion
Right
♦
Declination (J2000)
Proper
Declination
♦
Motion
Constellation
Load TLE
STK allows you to identify and insert satellites and facilities based on their
two-line element sets. There are two types of TLEs that can be loaded using
the Load TLE tool: facility and satellite.
Loading a Satellite TLE
You can perform a satellite TLE load using one of the default databases
shipped with STK or you can identify a database of your own to use in the
search. Choose the type of TLE load, then specify the TLE set file name.
Enter the correct file name in the Database field.
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Satellite Tool Kit® User’s Manual
City, Facility, Satellite & Star Databases
You can also cross-reference the TLE file with a specified database to provide
additional information. By default, the Cross-Reference Database option is
ON, and the path is set to the stkSatDb.* database shipped with STK. If
ON, search results include additional information such as the satellite’s
name, international number, owner, and mission. If OFF, results include
only the SSC number, TLE epoch. And rev number.
When you finish, click the Open button.
All Satellite TLE use the MSGP4 propagator. For additional information about the fields and
characteristics of the MSGP4 vehicle, please refer to Chapter 6 of this manual.
Open Database
Once you choose the file locations, the TLE Load Results window appears.
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1RWH
City, Facility, Satellite & Star Databases
If there are a number of items resulting from the search, select the item(s) of
interest in the list. Use the Select All button to select all items in the list. Use
the Deselect All button to deselect all of the selected items in the list.
Other options in the TLE Load Results window are described in the table
following.
Table 14-10. TLE load results options
Field
Description
Auto Propagate
If ON, ephemeris is propagated using the scenario Time
Period and the MSGP4 Propagator.
Time Step
Specifies the interval calculated ephemeris output points.
Start/Stop Time
Specifies the temporal boundaries of the vehicle's orbit.
Create Constellation
(Chains module only)
If ON, STK creates a constellation that includes all of the
satellites you selected. Enter the constellation's name in
the text box..
When you’re satisfied, click the OK button to insert the vehicle(s) into the
current scenario. The Browser and Map windows are updated to display the
new vehicle(s).
+LQW
You can insert more than one item at a time. If several items are highlighted, they are all
inserted when you click the OK button.
Loading a Facility TLE
If you choose to load a facility TLE, you can perform a TLE load using the
default file shipped with STK or you can identify a database of your own to
use in the search. The file contains Air Force TLE sets for facilities.
When you choose to load a facility TLE, the Cross-Reference Database option
is unavailable.
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Satellite Tool Kit® User’s Manual
City, Facility, Satellite & Star Databases
Open Database
Once you've chosen the TLE database, the TLE Load Results window appears.
The results window displays facility data available, including facility name,
latitude, longitude, altitude and an abbreviation.
If there are a number of facilities resulting from the search, select the items
of interest in the list. Use the Select All button to select all cities in the list.
Use the Deselect All button to deselect all of the selected facilities in the list.
Other options in the Facility Database Search Results window are described
in the table following.
Table 14-11. Facility TLE Load options
Field
Description
Create Facility or
Target Class
Choose to insert the facility as either a facility or target class.
Create Constellation
(Chains module only)
If ON, STK creates a constellation that includes all of the
facility you selected. Enter the constellation's name in the text
box.
When you’re satisfied, click the OK button to insert the selected items into
the current scenario. The Browser and Map windows are updated to display
the new facilities or targets.
You can insert more than one facility at a time. If several facilities are highlighted, they are
all inserted when you click the OK button.
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14-21
+LQW
City, Facility, Satellite & Star Databases
Object Description
If you load a facility or satellite using the TLE Load tool and the crossreference option is ON, the following information is entered into the
facility’s Long Description field.
♦
Facility ID
♦
Astronomical latitude
♦
Astronomical
longitude
♦
X-geocentric (m)
♦
Y-geocentric (m)
♦
Z-geocentric (m)
♦
Classification
♦
Location
♦
IOB type
♦
Range units
♦
Elevation limit 1 (deg)
♦
Elevation limit 2
(deg)
♦
Azimuth limit 1(deg)
♦
Azimuth limit 2 (deg)
♦
Minimum
(km)
♦
Maximum
(km)
♦
Time step
♦
MaxRF
14-22
range
range
Satellite Tool Kit® User’s Manual
15
REPORTS &
GRAPHS
Overview
The Report and Graph tools in STK summarize static data. They are available for
most objects and are helpful in presenting and visualizing relationships among data
elements. You can also include the data from one or more objects in a report or
graph. These tools are useful for high-level presentations of complex information.
Chapter Contents
Using the STK Report/Graph Tool..............................................................15-2
Changing Time Periods for Reports & Graphs ......................................15-3
Managing Report/Graph Styles ............................................................15-4
Report Window .........................................................................................15-5
Report Properties........................................................................................15-6
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15-1
Reports & Graphs
Content.................................................................................................15-7
Header................................................................................................15-11
Graph Window .......................................................................................15-12
Graph Properties......................................................................................15-15
Content...............................................................................................15-15
Layout.................................................................................................15-17
Using the STK Report/Graph Tool
The STK Report/Graph Tool window is the control panel for generating
reports and graphs. It allows you to open an existing report/graph style or
create a new one, change the time period of the report or graph, and manage
the report and graph styles available.
Figure 15-1. An example of the STK Report Tool window.
15-2
Satellite Tool Kit® User’s Manual
Reports & Graphs
Reports and dynamic displays use the same style files to define the content and format of
the report or dynamic display. If you change a report style, the dynamic display for that
same style also changes. If you wish to keep the original style but modify it, use the Make
Copy function. This is also true of graphs and strip charts
:DUQLQJ
Changing Time Periods for Reports
& Graphs
Many of the standard reports and graphs include time-dependent data. With
STK you can limit the time intervals for data reporting purposes and control
the time step without changing the scenario’s time parameters.
Time Intervals and Step Sizes are set for each section of the data. You can’t set time
intervals or step sizes for a single line or element.
1RWH
The contents of the entire report or graph are shown in the Contents list for reference
only.
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15-3
Reports & Graphs
The Time Period window for graphs doesn't display Section and Line information in the
Contents list. In addition the Write Intervals to Report option isn't available for graphs.
In the Contents list box, highlight the section for which you wish to
set time limits. The Start and Stop Times currently set for that section
appear in the Section Intervals portion of the Time Periods window. Use
the command buttons to add and modify the time periods for the
section. For Reports, you can also order the time periods.
:DUQLQJ
If you generate data using an extremely small Step Size over a long period of time, the
time STK requires to generate the report or graph is significantly increased.
To display actual times, turn the Use Ephemeris Steps option ON. This
option is useful when reporting external ephemeris. If this option is ON, you
can’t enter a Step Size. To print the time intervals for easy reference, turn the
Write Intervals to Report option ON. You can also change the Step Size used.
Managing Report/Graph Styles
A number of functions available through the STK Report/Graph Tool window
are the same for both reports and graphs. These functions are described
briefly in the table following.
Table 15-1. STK report/graph tool functions
15-4
Field
Description
Add
Inserts a style that doesn't appear in the Styles list. When you add
a style, STK copies the style file to your local location if it isn’t
currently saved in your local Styles directory.
Remove
Removes a style from the Style list. Although the style no longer
appears in the Styles list, you can retrieve it by using the Add
button.
Satellite Tool Kit® User’s Manual
Reports & Graphs
Field
Description
Make Copy
Copies an existing style.
New
Creates a new style.
Change
Changes the name of the selected style to that of the text entered
in the text box beneath the Styles list.
Report Window
A number of “standard” report styles were shipped with your STK system.
You can also customize a style to meet your needs. Reports can be created
for scenarios, vehicles, facilities, targets, stars, planets and sensors.
Select a style in the Style list and use the Create… button to display the report.
Options available in the Files menu when the report displays are discussed in
the following table.
Figure 15-2 . Sample report summarizing J2000 x, y, and z position for
the ERS1 and Shuttle vehicles
The options available in the report window are discussed in the table
following.
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Reports & Graphs
Table 15-2. Files menu options for report windows
Field
Description
Close
Closes the report window.
Print
Prints to the local printer.
Save As
Saves the report to a file
Export
Exports data to an ASCII file. Headers are in quotes and data
elements are delineated by commas.
Export Complete
Exports all report data to an ASCII file, including any summary
information.
Units
Opens a Units window that allows you to change the units of
measure for the report or graph. If the Use Default Report Units
option is ON, default units are used. If the Make Default Report
Units option is ON, the units of measure set here are used as the
default units for all data generated.
Changes made in this Units window do NOT affect the units set
at the scenario level or permanently change the units for the
report style.
Refresh
Redraws the report window to reflect changes made to the
object(s) (e.g., vehicle parameters) since the window was opened.
For changes made to the style definition, you must create a new
report window.
Report Properties
Reports are divided into sections and lines. Sections are blocks of similar
data. Data with different time dependencies must be placed in separate
sections of the report. Lines consist of various data elements included in the
report.
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Reports & Graphs
You can create a report that contains data for two or more object classes (e.g., facility and
vehicle).
+LQW
In the STK Report Tool window, you can define the contents and format of
the modified or new report style. Select the style in the list and use the
Properties button.
Content
The Content tab allows you to select the data elements to be included in
your report.
The report is organized by sections and then by lines of data. You can have
any number of sections and lines in the report. Data elements are shown in
an hierarchical format.
You can double click an item in the Elements list to copy it to the Report Contents. You can
also double click an item in the Report Contents list to remove it from the list.
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Reports & Graphs
STK automatically creates the first section and first line of a new report style for you.
1RWH
The first step in creating your own report style is to click the New Section
button. Next, create a new line of data by using the New Line button. Now
you can specify the data elements to be included in the first line. Copy the
element you wish to include in the report to the Report Contents list.
Use the Up and Down arrows to change the position of the items in the
Report Contents list. Add new lines and sections as needed. You can also
change the units of measure for a section, line or element using the Units
button.
:DUQLQJ
Changes you make to a particular section affect all lines and data elements associated with
that section. To change one line in a section, make your changes to the line after all
changes have been made to the section associated with that line.
Options: Section
If you select a section in the Report Contents list, the Options window
contains fields that allow you to specify the step size to be used for the entire
section, if the report data is time-dependent. You can specify a Title to display
at the top of the section.
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Table 15-3. Section options
Field
Description
Use Ephemeris Steps
Displays actual times in the report. Useful when reporting
external ephemeris. If ON, Step Size isn't available. Only
available for time-dependent data.
Step Size
Number of seconds per step. A step size of 300.00 is equal to
5 minutes. Only available for time-dependent data.
Multiple Instance
Only valid if multiple objects have been selected in the
Browser when generating the report. If the Include Instance
Name with Title option is ON, choose whether to display
one section for each object instance included in the report or
to display the data for an object on the same line in the report.
If ON, the name of the object displays in the section title.
If you generate a report using an extremely small Step Size over a long period of time, the
time STK requires to generate the report is significantly increased.
Options: Data Elements
If you select a data element in the Report Contents list, the Options window
contains fields that allow you to specify the type of information to be
included and format of the element. You can specify a title to use as the
column heading for the data element.
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Reports & Graphs
Table 15-4. Data element options
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Field
Description
Number of Decimal
Digits
The number of digits to display to the right of the decimal
point for real numbers.
Format
Choose among: Floating Point, Scientific (e) or Scientific (E).
Multiple Instance
This option is only valid if multiple objects have been
selected in the Browser when generating the report. If the
Include Instance Name with Title option is ON, the name of
the object displays in the column title.
Summary Options
Choose the appropriate Summary Options so that summary
data is generated for the element.
Summary Options are only available for some data elements. If they aren’t applicable to
the data element, these options are disabled.
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Reports & Graphs
Header
The Header tab controls the general format options for the report style.
There are five fields available in the Header tab.
Table 15-5. Report Header options
Field
Description
Title
Add a title at the beginning of the report. The title can’t exceed
one line of text, including spaces and punctuation.
Current Date
If ON, the current date displays at the top of the report.
Object Name
If ON, the name of the object(s) for which the report is being
generated appears at the top of the report.
Short Description
If ON, information contained in the Short Description field of
the Description tab for the object(s) is included in the report.
Long Description
If ON, information contained in the Long Description field of
the Description tab for the object(s) is included in the report.
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Reports & Graphs
Refer to Chapter 2, User Interface, for a complete discussion of the Description tab.
1RWH
Graph Window
You can use one of the standard graph styles shipped with STK to display
data or create a customized graph. In the STK Report/Graph Tool window,
use Create… to display the graph style selected. One of the most popular
standard graph styles is the Solar AER for a vehicle. An example of the graph
is shown in the following figure. Other standard graph styles are available for
vehicles as well as for facilities, targets and planets.
Figure 15-3. Sample X,Y Graph that displays the azimuth, elevation and
range of the Sun relative to the ERS1 vehicle.
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Reports & Graphs
The buttons available in the Graph Data window are described in the
table following.
Table 15-6. Graph Data buttons
Button
Description
Zooms in (magnifies) on a portion of the graph. Click this button,
then click and hold the left mouse button and drag it over the
portion of the graph you wish to magnify. Use this button as many
times as needed to increase magnification.
Restores the graph perspective one step at a time.
Immediately restores the graph to its original size.
You can also click a point in the graph to display its X and Y coordinates as
well as the Nearest X and Y Data Points to that point.
Use the Files menu to close, print, change units of measure, and refresh the
graph.
Defining Graph Attributes
Select the Attributes option in the Edit menu to define the appearance of the
graph.
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Reports & Graphs
The table following describes the options available in the Attributes window.
The options in this window are essential in differentiating among elements
for multiple objects in the graph.
Table 15-7. Graph attribute options
15-14
Field
Description
Title
Changes the legend title for the selected element.
The title can’t exceed one line of text, including
spaces and punctuation.
Line
Changes the color, style and/or width of the line
connecting data points in the graph.
Point
Changes the color, style and/or size of the
individual data points in the graph.
Satellite Tool Kit® User’s Manual
Reports & Graphs
Graph Properties
In the STK Graph Tool window, you can define the contents and format of
the modified or new graph style. Select the style in the list and use the
Properties button
Content
The Content tab allows you to select the data elements to be included in
your graph.
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Reports & Graphs
Before you choose the data elements you wish to
include in the graph, you must select a Graph Type. The
following graphs types are available.
Table 15-8. Graph type options
Graph Type
Description
Time XY
Displays data elements of the selected object(s) relative to time.
No options are available for the X axis because X equals time.
XY
Displays an XY plot of data elements of your choice for the
selected object(s).
Interval
Displays time line intervals for the selected object(s).
Polar
Displays a polar plot of data elements for the selected object(s),
where the center of the plot is 0°.
Polar 90
Displays a polar plot of data elements for the selected objects(s),
where the center of the plot is 90°.
Once you’ve selected a Graph Type, use the arrow buttons to assign the data
elements of interest to the appropriate axes listed on the right side of the window.
+LQW
You can double click an item in the Elements list to copy it to the Y axis Graph Contents
list. You can also double click an item in any of the Graph Contents lists to remove it from
the list.
Use the left arrow to remove elements from the axes list. You can also add a
title to each axis. If the Log10 option is ON, data points along that axis
display as log10 instead of linear.
You can also change the units of measure for a graph element using the Units
button.
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Options
You can change the graphical display of individual data elements for the style.
The name of the element appears in the Title field. Other options are
described in the table following.
Table 15-9. Graph element options
Field
Description
Line
Changes the color, style and/or width of the line connecting data
points in the graph.
Point
Changes the color, style and/or width of the individual data points
in the graph.
Layout
The fields in the Layout tab allow you to choose the general display options
for the graph.
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There are nine fields available in the Layout tab.
Table 15-10. Graph layout options
Field
Description
Title
Add a title to display at the top of the graph. The title can’t
exceed one line of text, including spaces and punctuation.
Current Date
If ON, the current date displays at the top of the graph.
Object Name
If ON, the name of the object(s) for which the graph is
generated appears at the top of the graph.
Show Tick Marks
If ON, tick marks display on the horizontal axis.
Show Grid Lines
If ON, grid lines display in the graph.
Number of Axis
Annotations
The number of points to be marked along the horizontal axis
in the graph.
Number of Tick Marks
The number of tick marks to display along the horizontal
axis.
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Field
Description
Number of Vertical
Grid Lines
The number of grid lines to display vertically on the graph.
Number of Horizontal
Grid Lines
The number of grid lines to display horizontally on the
graph.
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16
DYNAMIC
DISPLAYS & STRIP
CHARTS
Overview
STK now features a Strip Chart tool that displays user-selected data in graph
form as you animate the scenario. The Strip Chart is useful when you wish to
visualize dynamic data elements over a period of time. Another feature that is
useful in analyzing data is the Dynamic Display tool, which provides text
updates during animation so that you can view changes to selected elements
over a period of time.
Chapter Contents
Overview ...................................................................................................16-1
Chapter Contents.......................................................................................16-1
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Dynamic Displays & Strip Charts
The STK Dynamic Display/Strip Chart Tool Window ..................................16-2
Managing Dynamic Display/Strip Chart Styles ......................................16-3
Dynamic Display Window .........................................................................16-4
Dynamic Display Properties........................................................................16-5
Content.................................................................................................16-6
Strip Chart Window ...................................................................................16-8
Strip Chart Properties................................................................................16-10
Content...............................................................................................16-11
Layout.................................................................................................16-13
The STK Dynamic Display/Strip Chart
Tool Window
The STK Dynamic Display/Strip Chart Tool window is the control panel for
generating dynamic display reports and strip charts. It allows you to open an
existing style or create a new one and manage the dynamic display and strip
chart styles available.
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Dynamic Displays & Strip Charts
Figure 16-1. An example of the STK Dynamic Display Tool window.
Reports and dynamic displays use the same style files to define the content and format of
the report or dynamic display. If you change a report style, the dynamic display for that
same style also changes. If you wish to keep the original style but modify it, use the Make
Copy function. This is also true of graphs and strip charts.
Managing Dynamic Display/Strip
Chart Styles
A number of functions available through the STK Dynamic Display/Strip
Chart Tool window are the same for both Dynamic Display Reports and Strip
Charts. These functions are described briefly in the table following.
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Dynamic Displays & Strip Charts
Table 16-1. STK dynamic display/strip chart tool functions
Field
Description
Add
Inserts a dynamic display or strip chart style that doesn't appear
in the Styles list. When you add a style, STK copies the style file
to your local location if it isn’t currently saved in your local
directory.
Remove
Removes a style from the Style list. Although the style no longer
appears in the Styles list, you can retrieve it by using the Add
button.
Make Copy
Copies an existing style.
New
Creates a new style.
Change
Changes the name of the selected style to that of the text
entered in the text box beneath the Styles list.
Dynamic Display Window
The Dynamic Display tool makes it easy to view and analyze data. A number
of “standard” dynamic display formats were shipped with your STK system.
You can also customize a dynamic display to meet your needs. Dynamic
displays can be created for vehicles, facilities, targets and planets.
You can use one of the standard dynamic display styles shipped with STK to
display data. One of the most popular standard dynamic display styles is the
J2000 ECI Position Velocity dynamic display style for a vehicle. An example
of the dynamic display is shown in the following figure.
Select a style in the Style list and use the Open… button to open the dynamic
display.
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Dynamic Displays & Strip Charts
Figure 16-2. A sample standard dynamic display showing J2000
position and velocity data for the ERS1 vehicle. The data changes as the
animation moves forward or backward in time.
The options available in the display window are discussed in the table
following.
Table 16-2. Files menu options for dynamic display windows
Field
Description
Close
Closes the dynamic display window.
Units
Opens a Units window that allows you to change the units of measure
for the report or graph.. If the Use Default Report Units option is ON,
default units are used. If the Make Default Report Units option is ON,
the units of measure set here are used as the default units for all data
generated.
Changes made in this Units window do NOT affect the units set at the
scenario level or permanently change the units for the report style.
Dynamic Display Properties
You can create a report that contains data for two or more object classes (e.g., facility and
vehicle).
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Dynamic Displays & Strip Charts
In the STK Dynamic Display Tool window, you can define the contents and
format of the modified or new dynamic display style. Select the style in the
list and use the Properties button.
Content
The Content tab allows you to select the data elements to be included in
your dynamic display.
Use the right arrow button to assign the element(s) you wish to include in
the report to the Display Items list. Use the Up and Down arrows to change
the position of the items in the Display Items list. Use the left arrow to
remove an item from the Display Items list. You can also change the units of
measure for a display item using the Units button.
+LQW
You can double click an item in the Elements list to copy it to the Display Items list. You can
also double click an item in the Display Items list to remove it from the list.
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Dynamic Displays & Strip Charts
Option
The Options window allows you to set general data options for the dynamic
display data.
Table 16-3. Dynamic display options
Field
Description
Title
Title to be shown next to the display data for this item.
Number of
Decimal Digits
The number of digits tot display to the right of the decimal point
for real numbers.
Format
Choose among: Floating Point, Scientific (e) or Scientific (E).
Multiple Instances
Only valid if multiple objects have been selected in the Browser
when generating the dynamic display. If the Include Instance Name
with Title option is ON, the name of the object displays along with
the specified title.
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Dynamic Displays & Strip Charts
Strip Chart Window
The Strip Chart tool makes it easy to view and analyze dynamic data during
animation. You can use one of the standard strip chart styles shipped with
STK to display data. One of the most popular standard strip chart styles is
the ECF Position & Velocity strip chart style for a vehicle. An example of
the strip chart is shown in the following figure. Other standard strip chart
styles are available for vehicles as well as for facilities, targets and planets.
Figure 16-3. A sample standard strip chart showing ECF position and
velocity data for the ERS1 vehicle.
The buttons available in the Strip Chart Data window are described in
the table following.
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Dynamic Displays & Strip Charts
Table 16-4. Strip Chart data buttons
Button
Description
Zooms in (magnifies) on a portion of the graph. Click this button, then
click and hold the left mouse button and drag it over the portion of the
graph you wish to magnify. Use this button as many times as needed to
increase magnification.
Restores the strip chart perspective one step at a time.
Immediately restores the strip chart to its original size.
You can also click a point in the graph to display its X and Y coordinates as
well as the Nearest X and Y Data Points to that point.
Use the Files menu to refresh, close, save, print, and change units of measure
for the strip chart.
Defining Graph Attributes
Select the Attributes option in the Edit menu to define the appearance of the
chart. The options in this window are essential in differentiating among
elements for multiple objects in the graph.
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Dynamic Displays & Strip Charts
The table following describes the options available in the Attributes window.
Table 16-5. Strip chart attribute options
Field
Description
Title
Changes the legend title for the selected element. The title can’t
exceed one line of text, including spaces and punctuation.
Line
Change the color, style and/or width of the line connecting data
points in the chart.
Point
Change the color, style and/or width of the individual data points in
the chart.
Strip Chart Properties
To define the contents and format of the modified or new strip chart style,
select the style of interest and use the Properties… button.
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Content
The Content tab allows you to select the data elements to be included in
your strip chart.
For strip charts, the graph type is set to Timeline XY. This can't be changed.
The Timeline XY graph type displays data elements of the selected object
relative to time. No options are available for the X axis because X equals
time.
The right arrow button to assign the data elements of interest to the
appropriate axes listed on the right side of the window.
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Dynamic Displays & Strip Charts
+LQW
You can double click an item in the Elements list to copy it to the Y axis. You can also
double click an item in any of the axes to remove it from the list.
Use the left arrow to remove elements from the axes list. You can add a title
to each axis. If the Log10 option is ON, data points along that axis display as
log10 instead of linear. You can also change the units of measure for a graph
element using the Units button.
Options
You can change the graphical display of individual data elements for the style.
The name of the element appears in the Title field. Other options are
described in the table following.
Table 16-6. Graph element options
Field
Description
Line
Change the color, style and/or width of the line connecting data
points in the chart.
Point
Change the color, style and/or width of the individual data points in
the chart.
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Layout
The fields in the Layout tab allow you to choose the general display options
for the strip chart.
There are a number of fields available in the Layout tab.
Table 16-7. Strip chart layout options
Field
Description
Title
Add a title to display at the top of the graph. The title can’t exceed
one line of text, including spaces and punctuation.
Current Date
If ON, the current date displays at the top of the graph.
Object Name
If ON, the name of the object(s) for which the graph is generated
appears at the top of the graph.
Show Tick Marks
If ON, tick marks display on the horizontal axis.
Show Grid Lines
If ON, grid lines display in the graph.
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Dynamic Displays & Strip Charts
Field
Description
Number of Axis
Annotations
The number of points to be marked along the horizontal axis in
the graph.
Number of Tick
Marks
The number of tick marks to display along the horizontal axis.
Number of Vertical
Grid Lines
The number of grid lines to display vertically on the graph.
Number of
Horizontal Grid
Lines
The number of grid lines to display horizontally on the graph.
Viewable Duration
The length of time for which the strip chart elements display
before updating.
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17
USING THE STK
HELP MENU
Overview
STK features a Help system that you can reference for help on functions and
options available in STK. You can access Help files while in the Browser
window or through individual tabs and windows in STK. STK Help is
available through the Help menu at the top of the Browser window or by
clicking on the Help button on the bottom right-hand side of STK windows.
If you access Help through a window other than the Browser, the Help files
for the specific window display; if you access Help from the Browser, the
Overview or Contents displays.
Chapter Contents
STK Help Topics..........................................................................................17-2
Selecting an HMTL Browser..................................................................17-2
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Using the STK Help Menu
Opening Help from the Browser Window...........................................17-3
Opening Help from a Property Window..............................................17-3
Licensing....................................................................................................17-3
Password Window (Initial Start-Up).......................................................17-4
Requesting Licenses by E-Mail or FAX ...................................................17-5
Entering Licenses ..................................................................................17-6
Network Passwords ..............................................................................17-8
On-Line Manuals........................................................................................17-9
About STK...................................................................................................17-9
AGI Web Site..............................................................................................17-9
Other Help Menu Items .............................................................................17-9
STK Help Topics
STK offers a comprehensive on-line Help system to assist you in performing
tasks and functions in STK. The Help system provides information about
STK features as well as instructions for using STK functions and tools.
Selecting an HMTL Browser
For UNIX, STK’s Help files are provided in HTML (hypertext mark-up
language) format. When you install STK, you are asked to select the internet
Browser application of choice (Netscape®, Mosaic®, etc.). This application
is then used to launch the Help files in STK whenever you request Help from
within STK. You don’t have to be connected to the internet to use the
Browser but you do need a Browser to view the HTML Help files. Most
workstations now ship with a Browser. If you don’t have a Browser, you can
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Using the STK Help Menu
purchase Netscape Navigator® at a local computer store or you can
download a shareware version of Netscape at www.netscape.com.
Opening Help from the Browser
Window
To display Help files from the Browser window, select STK Help Topics from
the Help menu at the top right-hand corner of the window. If you have an
add-on module, such as Comm or Coverage, Help files are listed as separate
items in the Help menu.
Opening Help from a Property
Window
If you need to open the Help system from any Property window, use the
Help button located on the bottom right-hand side of any Property window.
A Help file for the specific tab appears in the Help window.
Licensing
To run STK you will need one or more software licenses. The STK interface
provides an easy, orderly procedure for obtaining the necessary licenses.
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Using the STK Help Menu
Password Window (Initial Start-Up)
When you start STK for the first time, a Password window appears,
indicating that STK is unable to find a password.
The Password window presents the following options:
Table 17-1. Password options
17-4
Button
Description
Request via AGI
Web Site
Obtain your license(s) via the web. If you choose this option, STK
launches your web browser and connects you to AGI’s web site.
Request via EMail/FAX
If you wish to obtain your license(s) via e-mail or fax, select this
option to display an e-mail/FAX form that can be used to send
AGI the correct information.
Enter Passwords
After you obtain your password(s), select this option to display the
STK Licenses window.
Satellite Tool Kit® User’s Manual
Using the STK Help Menu
Requesting Licenses by E-Mail or
FAX
If you choose to obtain passwords using the Request via E-Mail/FAX option, a
Request window appears.
The following fields appear in the window.
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Using the STK Help Menu
Table 17-2. Request for licenses via e-mail/fax
Field
Description
Registrant’s
Information
Enter your name and other information. AGI needs an e-mail
address or FAX number to return your passwords. Also indicate
how you heard about STK 4.0 by selecting the appropriate option.
Company
Information
Enter your company name and other information about your
company.
Computer
Information
The Host ID# for your computer automatically appears in the
Host ID #; you don’t need to provide this data. Indicate the
Platform on which you’ll be running STK in the Platform field.
When you finish, click OK to generate a text file that can be e-mailed or
FAXed to AGI.
Entering Licenses
Use the Enter Passwords option in the Password window or select Licenses…
from the Help menu in the STK Browser window to open a Licenses window.
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Table 17-3. License window options
Field
Description
HostID
This number is generated automatically during installation and
can’t be altered.
Type
Select Demo or Permanent, depending on the kind of licenses
being entered. STK 4.0 licenses are Permanent.
Update
Passwords
Choose either:
®
♦
Load from File – Specify the correct file name for the
licenses. If you obtained passwords via e-mail, the e-mail
contains information about where to save and what to
name the passwords file.
♦
Enter Manually – Use the Product Password Table in this
window to manually enter Passwords and Host ID or
Expiration Dates.
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Using the STK Help Menu
Field
Description
Product
Passwords
The table contains a list of all STK products that are available as well
as any valid licenses that have been entered. To enter new
passwords manually, select the product of interest in the product
table, then enter the Password and, if applicable, the Expiration
Date in the text boxes below the table. Use the Update button to
apply the licenses.
Export Passwords
to File
Export passwords to an ASCII text file.
Network Passwords
You can also enter network passwords using the Load Network Passwords
button.
To enter network licenses for STK Professional and add-on modules, use the
text boxes beneath the Network Licenses Table to enter the Server ID number, IP
Address, Port and License number. When you finish, use the Update button.
Use Clear to clear all entries in the table and Delete to remove the selected
entry from the table.
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Using the STK Help Menu
On-Line Manuals
Full user documentation is provided on-line for your convenience. These
files are stored in portable document format (PDF) and can be viewed using
the Adobe Acrobat Reader 3.0®. When you installed STK, you were asked
whether you wished to install the Reader along with the PDF files. The
Reader is also available at www.adobe.com as free-ware. PDF files can be
printed in full. In addition, they are word searchable.
About STK
This selection provides you with valuable information about STK, including
customer support numbers and sales information. You can also open this
window to determine the software release version you’re using.
AGI Web Site
STK now has an on-line update feature to enable easy updates of TLE sets,
databases and more. Just select Online Update from the Help menu to open
the STK web site.
Other Help Menu Items
Additional items in the Browser window’s Help menu include the following:
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Using the STK Help Menu
Table 17-4. Additional Help menu items
Element
Description
Quick Start Guide
Includes a Warp Speed Start to get you up and running quickly
with STK, a Quick Start Tutorial, definitions of some of the most
basic STK concepts and a guide to the essentials of the STK user
interface.
Astro Primer
An astronautics primer designed to provide the reader with an
introduction to important topics in orbital mechanics, including a
brief overview of space, space missions and space history.
AGI Add-ons
A brief overview of add-on modules available to enhance the power
of STK.
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Satellite Tool Kit® User’s Manual
18
CHAINS MODULE
Overview
The STK Chains module is a multisatellite, multitarget/ground station
productivity tool that is easy to use. Chains provides you with powerful
analysis capabilities that aren’t available in any other off-the-shelf package.
Chapter Contents
Overview ...................................................................................................18-1
Chains & Constellations..............................................................................18-2
Basic Properties of a Chain .........................................................................18-3
Definition ..............................................................................................18-4
Constellations.............................................................................................18-5
Basic Properties of a Constellation..............................................................18-6
Constellation.........................................................................................18-6
Generating Reports for a Chain .................................................................18-8
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Chains Module
Creating Graphs for Chains..................................................................... 18-12
Dynamic Display Reports & Strip Charts................................................... 18-13
Chains & Constellations
The Chains module allows you to extend the pair-wise analysis capabilities of
STK to include accesses to and from satellite constellations, ground station
networks, groups of targets and multiple sensors. For instance, you can
determine the time period in which a satellite can see a target and a relay
station and the relay station can see a ground station. With Chains, you can
also group objects together — a powerful capability that allows you to check
accesses to the entire group. For example, you can determine when a tank has
access to at least four satellites in the Global Positioning System (GPS)
constellation.
In addition, you can easily determine when LandSat can see a target as well as
a TDRS relay satellite, and the relay satellite can, in turn, see a ground station.
In STK’s Chains module, that chain could be defined as:
Target1 – LandSat – TDRS_East – WhiteSands
You could also define a chain with a target to a LEO satellite to a relay
satellite to a ground station. Or you can solve more sophisticated problems
such as allowing the use of TDRS-East or -West as the relay satellite. In
Chains, you would define a constellation of relay satellites and then
incorporate that constellation into a chain.
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Satellite Tool Kit® User’s Manual
Chains Module
Figure 18-1. A simple chain defined as Target- LEO - Relay - Ground
Station. Picture captured in STK’s Visualization Option (VO) module.
When the Chains module is activated, the STK Browser window includes a
Chains icon ( )and a Constellation icon ( ) in the lower portion of the
window.
The name of a chain object should adequately describe the objects within and/or intent of
each chain to help you distinguish among chains and to facilitate use of the chain in a
scenario.
+LQW
Basic Properties of a Chain
A chain is a list of objects (either single or constellation) in order of access.
To identify the objects in a chain, select Basic in the Properties pull-down
menu.
Because chains consist of a number of different objects, there is no one marker in the Map
window for a chain. Therefore, a chain doesn’t possess graphics properties.
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18-3
1RWH
Chains Module
Definition
The Define tab allows you to identify the objects in the chain and to order
those objects for access purposes.
In the Available Objects list, use the right arrow or double click on the object
you wish to include in the chain to move it to the Chain Objects list. You can
also use the double click feature to remove an object from the Chain Objects
list.
You can include a mix of object classes in a single chain. The example chains
shown in this chapter include a constellation, which is explained in detail on
page 18-5. Constellation properties can affect access calculations for a chain
(refer to page 18-7 for a detailed explanation of constellation criteria).
Use the up and down arrows to change the order of the objects in the Chain
Objects list. Since the access calculations for the chain you create are
performed for the objects in the order they’re listed in the Chain Objects list
box, consider the ordering of the objects carefully.
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Satellite Tool Kit® User’s Manual
Chains Module
Figure 18-2. A more complex chain defined as 2 Targets - Leo - 2 Relays - 2
Ground Stations. Picture captured in STK’s Visualization Option (VO)
module.
Constellations
With STK Chains module, you can group a set of like objects, such as a group
of facilities, ground stations or satellites, into a single unit called a
constellation. Constellations differ from chains in that they group objects
together and can be included as an object of a chain.
The name of a chain object should adequately describe the objects within and/or intent of
each chain to help you distinguish among chains and to facilitate use of the chain in a
scenario.
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18-5
+LQW
Chains Module
Basic Properties of a Constellation
The objects which comprise the constellation define it. To identify the objects
in a chain, select Basic in the Properties pull-down menu.
1RWH
Because constellations consist of a number of different objects, there is no one marker in
the Map window for a constellation. Therefore, a chain doesn’t possess graphics properties.
Constellation
The Constellation tab allows you to identify the objects in a constellation and
to impose access limitations upon that group of objects.
In the Available Objects list, use the right arrow or double click the object you
wish to include in the chain to move it to the Constellation Objects list. You
can also use the double click feature to remove an object from the
Constellation Objects list.
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Satellite Tool Kit® User’s Manual
Chains Module
Setting Constellation Criteria
Once you’ve selected the objects that comprise the constellation, use
the Constellation Objects option to choose one of four constellation
criterion. The choices available allow you to specify the criteria that will
be used when the constellation is combined with other objects in a
chain. Options are discussed in the table following.
Table 18-1. Constellation criteria options
Option
Description
Any of
EITHER/OR criteria. Select this if any one object in the constellation
meets the needs of a chain for a successful access. For example, if the
constellation is defined as a group of three ground stations (A, B, and C)
and is built in a chain with a single vehicle, results show when the vehicle
can access ground station A or ground station B or ground station C.
All of
AND criteria. Select this if all objects in the constellation meet the needs
of the chain for a successful access. For example, results show when the
vehicle can access ground station A and ground station B and ground
station C (called coincident coverage).
At Least N
AND/OR criteria. Select this if at least the specified number of objects in
the constellation meet the needs of the chain for a successful access. In
the text box to the right of the option menu, enter the minimum number
of objects that must meet the needs of the chain for a successful access.
For example, if the minimum number is set to 2, results show when the
vehicle can access ground stations:
♦
A AND B or
♦
B AND C or
♦
A AND C
or
♦
A AND B AND C
Another good example of this criteria is the Global Positioning System
(GPS), where you could specify At Least 4.
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Chains Module
Option
Description
Exactly N
ONLY criteria. Select this if the exact specified number of objects in the
constellation meet the needs of a chain for a successful access. In the text
box to the right of the options menu, enter the exact number of objects
needed to meet access requirements. For example, if the exact number
specified is 2, results show when the vehicle can access both ground
stations:
♦
A AND B or
♦
B AND C or
♦
A AND C
♦
but NOT A AND B AND C
You could also specify Exactly 0 to determine when no satellite is in the
object’s view.
Generating Reports for a Chain
A number of specialized reports are available for the chain object using the
Report tool.
Individual Strand Access
A strand represents one possible access pathway through the chain. For a
chain defined by a series of individual objects, only a single strand is possible.
In the case where one or more objects in the chain are constellations, multiple
strands are possible. Further, the constellation access conditions (i.e., ANY
OF, ALL OF, AT LEAST N, EXACTLY N) determine the number of possible
strands for a chain that includes constellation objects.
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Satellite Tool Kit® User’s Manual
Chains Module
Figure 18-3. Diagram showing possible strand accesses from both Target1
and Target2 to Leo to both Relay1 and Relay2 to GroundStation. Individual
strand access for Target1-Relay2-GroundStation is shown in bold.
Leo
Relay1
Target1
Target2
Relay2
GroundStation
Individual strand access for this diagram would include access times for:
Target1-Leo-Relay1-GroundStation
Target1-Leo-Relay2-GroundStation
Target2-Leo-Relay1-GroundStation
Target-2-Leo-Relay2-GroundStation
The Individual Strand Access Report shows the access periods for each of the
possible access pathways through the chain.
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18-9
Chains Module
Individual Object Access
Individual object access is the accumulated total of all strands that include the
object in question.
Figure 18-4. Diagram showing individual object access for Relay1 (access
shown in bold lines).
Leo
Relay1
Target1
Target2
Relay2
GroundStation
Individual object access for Relay1 in this diagram would include access times
for:
Target1-Leo-Relay1-GroundStation
Target2-Leo-Relay1-GroundStation
The Individual Object Access Report lists pair-wise access times for each object
in the chain.
+LQW
Use the scroll bars on the right and bottom of the window to view additional data. You can
also click and drag the corner of the window to enlarge the size so that all data displays.
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Satellite Tool Kit® User’s Manual
Chains Module
Complete Chain Access
The complete chain access is the time period during which access between all objects
in a chain is possible through one or more individual strands. A chain access
encompasses the total contiguous time period during which mutual visibility of all
chain objects is possible through one or more individual strands.
The Complete Chain Access Report shows access times during which access
between all objects in a chain is possible through one or more individual strands.
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18-11
Chains Module
The Report window can remain open even if the STK Report Tool window is closed.
+LQW
Creating Graphs for Chains
Graphing functions are also available for the coverage definition and figure of
merit objects. Choose the graph type you wish to create, then choose the
appropriate elements for the X and Y axes. When you finish, use the Display…
button to display the graph.
Interval Strand Access Graph
Following is an example showing individual strand access graph.
Figure 18-5. Sample Graph showing accesses for each individual strand
and object in the Chain as well as complete access.
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Satellite Tool Kit® User’s Manual
Chains Module
Angle Between Graph
Following is a sample graph showing angles between objects.
Figure 18-6. Graph window displaying angle between objects in the
chain.
Dynamic Display Reports & Strip Charts
STK now features a Strip Chart tool that displays user-selected data in graph
form as you animate the scenario. The Strip Chart is useful when you wish to
visualize dynamic data elements over a period of time. Another feature that is
useful in analyzing data is the Dynamic Display tool, which provides text
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18-13
Chains Module
updates during animation so that you can view changes to selected elements
over a period of time.
For further information on Dynamic Displays and Strip Charts, see Chapters 15
and 16 of this manual.
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Satellite Tool Kit® User’s Manual
APPENDIX A
GLOSSARY OF TERMS
Accelerator Keys
Keys that speed up access to an action performed
in STK. Identified by an underlined letter in the
option’s name or a key combination appearing to
the right of the option’s name in a pull-down
menu.
Access
The geometric and temporal relationships between
objects that meet or exceed the constraints on the
objects, so that some task requiring both objects
can be performed.
Aitoff
See Hammer-Aitoff.
Altitude
The distance from an object to the surface of the
central body measured positive along an outward
normal to the central body surface.
Angle Unit
Specifies the measure of unit to be used when
referring to angles. Options are degrees and
radians.
Animate
The process of displaying the movement of objects
within a scenario on the map for a specified period
of time.
Animation
A Basic Properties tab that allows the user to set
the animation’s start time, end time/loop time,
time step/x real-time/real-time, and refresh
delta/high speed.
Satellite Tool Kit®
Apparent Position
Refers to the viewed position of the object from
the observer at a given time, which takes into
account the light time delay and aberrations.
Application
Contains the scenario and all objects within the
scenario. Basic Properties can be set at the
application level.
Apoapsis
The point of an elliptical orbit that is farthest away
from the gravitational center of the system
consisting of the primary body and the satellite
(called the apogee in Earth-based systems).
Apogee
The point in the satellite’s orbit that is farthest
from the gravitational center of the Earth.
Apogee Altitude
Altitude of the apogee of an orbit where apogee is
defined as the point in the orbit which is farthest
from the center of the central body.
Apogee Kick Motor (AKM)
A motor used once during the lifetime of a
geostationary satellite to provide the large delta-v
required to turn a highly elliptical orbit with
apogee at the geostationary altitude into a circular,
geostationary orbit. Apogee Kick Motors are
needed because many launchers are not able
deliver a satellite into geostationary orbit. (the
Russian Proton launcher is an exception to this
rule.)
A-1
Glossary of Terms
Apsis
One of the extreme end points of the major axis of
an elliptical orbit, such as the apogee or perigee.
Area Target
Defined geographical region of interest on the
ground.
Argument of Perigee
The angle from the ascending node to the perigee
direction measured in the orbit plane and in the
direction of the object’s motion.
Ascending Node
The point where the satellite passes through the
inertial equatorial plane moving from south to
north.
Atmospheric Drag
A retarding force acting on a satellite within the
Earth's atmosphere. At altitudes below 160 km,
the atmosphere causes a satellite’s orbit to decay
(fall back to Earth) within a few revolutions. At
altitudes above 700 km, drag has hardly any
influence.
Attitude
The orientation of the three principal axes of an
object relative to a reference coordinate system.
Also, [Vehicle:Basic Properties] allows the user to
specify the static or dynamic orientation of a
vehicle.
Auto Save
[Application:Basic Properties] Allows the user to
specify the directory path and time intervals to be
used when saving the scenario, activate or disable
automatic saving of work completed at the
specified intervals, perform a quick save of the
scenario, and specify whether vehicle ephemeris
should be saved during an Auto Save or Quick
Save.
Azimuth
The arc of the horizon measured clockwise from
north from 0° to 360°.
A-2
Azimuth Angle
Azimuth is measured in the plane perpendicular to
nadir from the projection of the velocity vector to
the projection of the relative position vector. This
angle is measured in a positive manner according
to the right-hand rule about the nadir vector.
Azimuth Rate
The time rate of change of the azimuth angle,
usually expressed in degrees per second or radians
per second.
Azimuthal Equidistant
A Map projection type that is mathematically
based on a planet tangent to the Earth. Spacing of
the parallels is uniform.
B1950
Standard epoch defined as the beginning of the
Besselian year 1950 (when the longitude of the
mean Sun is 280.0° measured from the mean
equinox) and corresponds to 31 December 1949
22:09:07.2 or JD 2433282.423.
Basic Properties
[Properties menu] Properties menu option for
each object in STK, including a scenario. Basic
Properties of an object define the object’s
parameters and special features
Boresight
The electromagnetic axis of an antenna that
defines the direction in which the antenna is
pointing.
Browser Window
Displays the classes and instances of all objects
within the STK application. It enables you to
control the information being displayed. At the
top of the window are four pull-down menus:
Files, Properties, Tools and Help. In the lower
portion of the window is a group of icons
representing each of the object classes available in
STK.
Satellite Tool Kit®
Glossary of Terms
Cartesian Elements
Specify an orbit by three position elements and
three velocity elements in a rectangular coordinate
system.
Constraints Properties
[Properties menu] This window allows the user to
specify the constraints that have been imposed
upon the selected object.
Check Box
Allows the user to flip between two opposite
conditions. When a check box displays a check
mark, the option is ON.
Coordinate Type
Set of orbital elements. Some coordinate sets are
more useful in certain situations than others.
Class
Objects in STK are arranged in classes that share
common attributes and traits. There are eight
classes in STK: scenario, vehicle, facility, target,
area target, planet, star, sensor
Classical Elements
Also known as Keplerian elements. These elements
specify an orbit by its size, shape, and threedimensional orientation in inertial space.
Clock Angle
An angle measured in the plane perpendicular to
an antenna boresight from the up vector for the
sensor.
Close
[Files menu] Close a scenario without exiting
STK. When you close a scenario, the Map window
disappears.
Conic
A shape defined as a cross-section of a right
circular cone. Cross-sections at various angles
through the cone generate circles, ellipses,
parabolas, and hyperbolas. Also a type of sensor
defined through the specification of an origin and
axis directions. The components of vectors specify
the orientation of the vectors within a specific
coordinate system.
Constraint
A boundary condition placed on a parameter that
limits its validity to a subset of its original range.
®
Satellite Tool Kit
Coordinate System
A system in which positions are specified by a set
of coordinates.
Coverage
The area of the Earth’s surface visible to an
orbiting spacecraft during one or more orbits. A
coverage pattern is the sequence of coverage over
an extended period of time.
Date Format
Specifies the format to be used when referring to
calendar dates. Available formats include: UTC
Gregorian, UTC Julian, Local Julian, Local
Gregorian, Epoch Seconds.
Declination
An angle in a meridian, measured northward from
the ecliptic to a line running from the Earth’s
center to a given celestial object.
Delaunay Elements
A set of canonical angle-action variables
commonly used in general perturbation theories.
An orbit is defined by a set of conjugate angleaction pairs.
Delta-v
The speed change needed for a change in orbit
parameters. The direction and size of the delta-v
determines which orbit parameters are most
affected, and to what extent. For instance, a deltav orthogonal to the orbit plane at the time it
crosses the ascending or descending node results
in an inclination change. The latter maneuver
requires a relatively large amount of propellant;
tight inclination control therefore limits the
lifetime of a satellite in orbit considerably.
A-3
Glossary of Terms
Descending Node
The point in the equatorial plane where the
satellite crosses through it in a southerly direction.
Description
[Object:Basic Properties] Allows you to record
ancillary information for future reference.
Contains short and long description fields.
Detector Pitch
The pitch angle relative to a body-centered
coordinate system of a detector.
Diameter
A straight line passing through the center of a
circle or sphere and meeting the circumference or
surface at each end.
Digital Terrain Elevation Data (DTED)
A collection of position and height data produced
by the National Imagery Mapping Agency.
Direct Sun
The condition in which the Sun is observed to be
entirely unobscured.
Distance Unit
[Application:Basic Properties] Specifies the unit of
measure to be used when referring to distance.
Options are: feet, kilometers, statute miles,
meters, and nautical miles.
Drift Orbit
The slow movement of a geostationary satellite
toward its final location. A new geostationary
satellite is usually delivered in an orbit slightly
higher or lower than its final orbit, then appears to
drift slowly toward its final location. The satellite
may be halted temporarily (through a Hohmann
Transfer) at an intermediate location to allow it to
be tested without causing interference, after which
it continues its drift to its final location.
ECI (Earth-Centered Inertial)
A coordinate system with its origin at the center
of the Earth and axes which are fixed in inertial
space. Used as a display option for orbits in the
Perspective map projection.
A-4
ECF (Earth-Centered Fixed).
A coordinate system with its origin at the center
of the Earth and axes which are fixed in the central
body. Used as a display option for orbits in the
Perspective map projection. With this option, the
orbit track always appears above the ground track.
Eccentricity
Measure of the flatness of an ellipse. A value of 0
indicates a circle. For an elliptical orbit: e = c/a,
where c is the distance from a focal point to the
center of the ellipse, a is the semimajor axis and 0
< e < 1.
Eccentric Anomaly (E)
An auxiliary angle used in the integration of
Newton's equations for elliptical motion. E is the
angle between the main axis and line running from
the center of the ellipse to a point Q on a circle
circumscribed about the ellipse. The point Q is a
projection of the satellite along a line parallel to
the minor axis of the ellipse. The angle E appears
in the famous Kepler's Equation that relates E, M
and i.
Eclipse
Passage of a satellite through the Earth's shadow.
There are two periods in the year, each of about 40
days’ duration, centered around vernal and
autumnal equinox, when a geostationary satellite
passes through the shadow of the Earth daily. A
geostationary communications satellite needs to be
equipped with batteries to avoid traffic
interruptions during an eclipse.
Ecliptic
The plane of the Earth's revolution around the
Sun.
Elevation
The angle above or below the horizon plane as
measured from -90° at the nadir to +90° at the
zenith.
Elevation Angle
Elevation is measured as the angle between the
nadir vector and the relative position vector minus
Satellite Tool Kit®
Glossary of Terms
90°. The elevation angle is positive for objects
above this plane.
Elevation Rate
The time rate of change of the elevation angle,
usually expressed in degrees per second or radians
per second.
End Time
The time at which animation ends.
Ephemeris
A time-ordered tabulation of vehicle position for a
number of dates.
Ephemeris Time (ET)
A time measurement calculated from the observed
motion of the moon, introduced to eliminate
dependency on the Earth’s rotation.
Measurements with highly accurate atomic clocks
show that the rotation period of the Earth is
slightly irregular, but, in practice, the difference
between ET and Universal Time (UT) may be
ignored. The absolute difference between the two
measurements has increased over the last 100 years
to about 60 seconds.
Epoch
An arbitrary, fixed instant used as a chronological
reference for celestial reference systems and orbital
motions.
Epoch Seconds
Date calculated in seconds relative to the epoch
time specified in the scenario’s Time Period tab.
Equation of the Center
The relation between True and Mean Anomaly,
used as a first approximation to Kepler's Equation.
In its simplest form: f = M + 2e sin M, where f =
True Anomaly, M = Mean Anomaly and e =
eccentricity.
Equation of Time
The difference between Mean Solar Time and real
solar time, ranging from a minimum of -15 to a
maximum of +15 minutes during the year.
®
Satellite Tool Kit
Equidistant Cylindrical
A Map projection type that is mathematically
based on a cone that is tangent at one parallel or
conceptually secant at two parallels. North or
south pole is represented by an arc.
Equinoctial Elements
Specify an orbit by the size and a set of composite
elements that collectively describe the shape and
orientation of the orbit. The composite elements
are the projections of the eccentricity and nodal
vectors onto the orbit plane. This element set has
the advantage of being well defined for all orbit
types.
Equinox
The moment at which the Sun, as viewed from the
Earth, appears to cross the celestial equator. The
vernal equinox occurs on 21 March of each year
while the autumnal equinox occurs on 22
September.
Exclusion Zone
An area on the Earth’s surface inaccessible to a
spacecraft’s antennas or sensors. For example, the
areas near the pole are exclusion zones for
geostationary satellites. May also refer to a region
of space within which a vehicle may not be
accessed.
Exit
[Files menu] Quit the current STK session.
Facility
A fixed location on the Earth’s surface
representing ground stations, launch sites, tracking
station, or other structures providing satellite
support functions.
Field of View (FOV)
The subtended angle of visibility for a viewing
object or sensor.
Figure of the Earth
The shape of the Earth as approximated by a
spheroid of revolution, i.e. a geometrical shape in
which any cross-section parallel to the equator is a
circle, and any cross-section through the north-
A-5
Glossary of Terms
south axis is an ellipse of which the minor axis
coincides with the Earth's axis.
The shape of the ellipse is specified by two of the
following values (WGS 1984):
Equatorial Radius (a) = 6378 137.0 m
Free-Space Loss
Signal attenuation that would occur on a link
between an isotropic antenna on the surface of the
Earth and one on board a satellite in the absence of
any propagation effects such as atmospheric
absorption, diffraction and obstruction.
Polar Radius (b) = 6356 752.3 m
Flattening (f) = 1/298.257223563
Fixed Apogee Altitude
Used to specify the maximum altitude for a
rocket.
Fixed Coordinate System
A coordinate system fixed with respect to the
rotating Earth. The principal direction, x, is
through the equator at 0° longitude, z is through
the Earth’s rotation axis, and y completes the
right-handed system.
Fixed Delta V
Instantaneous thrust to be applied to the vehicle
being launched.
Fixed Time of Flight
Used to specify the launch to impact time for a
rocket.
Focal Length
The distance from the center of a focusing device
such as a lens or mirror to the point where the
refracted or reflected rays converge. Focal length
determines the magnification of the images
formed.
Footprint of a Satellite
The point on the surface of the Earth directly
below a satellite. The footprint is the intersection
of the Earth's surface and the line connecting the
center of the Earth to the satellite.
Footprint
That portion of the Earth's surface from which the
elevation angle toward a satellite exceeds a
specified value (usually 0°, 5° or 10°).
A-6
Frequency
The number of cycles or completed alternations
per unit time of a wave or oscillation.
Geocentric
The latitude and longitude of a point on the
Earth’s surface determined from the geocentric
vertical.
Geodetic
The latitude and longitude of a point on the
Earth’s surface determined from the geodetic
vertical (normal to the specified spheroid).
Geostationary Orbit
A circular posigrade orbit in the equatorial plane
of the Earth with an orbital period of exactly one
sidereal day. The radius of a geostationary orbit is
6.6107 (equatorial) Earth radii.
Graphics Properties
[Properties menu]. This window allows the user to
specify characteristics of the selected object as
displayed in the Map window.
Grazing Altitude
The distance from the Earth’s surface to the line of
sight between two vehicles at the point where their
intersection is perpendicular.
Grazing Angle
Used to describe how high one vehicle appears
above the edge of the Earth relative to another
vehicle. Measured relative to the primary vehicle as
the angle between the Earth limb and the
secondary vehicle.
Great Arc
Vehicle that follows a point-by-point path over the
surface of the Earth at a given altitude. Paths
which lie in a plane that intersect the center of the
Satellite Tool Kit®
Glossary of Terms
Earth, called Great Arc paths, are used to connect
the waypoints.
Greenwich Mean Time (GMT)
The time as measured on the prime meridian
running through Greenwich, England. There are
two definitions of GMT. The first is based on
Universal Time (UT)1, which is subject to
irregularities in the rotation of the Earth. The
second is based on Universal Time Coordinate
(UTC), which is a uniform time and is the
definition used in STK. For precise purposes, it is
recommended that the term UTC be used.
Ground Elevation Angle
Elevation angle is measured , relative to the target
or facility, as the angle between the local horizon
and the vehicle.
Ground Sample Distance
The smallest size of a resolvable object for a sensor
at a known range and angle of incidence.
Ground Track
The trace of the vehicle subpoints on the Earth’s
surface as it orbits around the Earth.
Half Angle
The angle between the axis of a right circular cone
and its surface.
Half-Power
The angle in an antenna radiation pattern in which
the transmitted or received power is diminished by
one-half of the power as measured at the
boresight. This is equivalent to a three-decibel
difference.
Hammer-Aitoff
A Map projection that is a variation of the
Lambert Azimuthal equal area projection which
allows for viewing at both hemispheres
simultaneously. The equal area characteristic of the
Lambert projection is mostly preserved.
®
Satellite Tool Kit
High Speed
Refresh screen as fast as the system is able for
animation purposes. Doesn’t rely on a timer to
begin the refresh process.
Hohmann Transfer
A transfer between two circular coplanar orbits via
an intermediate elliptical orbit of which the perigee
is tangent to the smaller circle and the apogee is
tangent to the larger circle. A Hohmann Transfer
is the most economical transfer from the
standpoint of delta-v, i.e. the amount of propellant
required. It also takes longer than any other
possible orbit transfer. Note that a Hohmann
Transfer requires two burns: a start and a stop
burn.
Horizon
The plane tangent to the Earth’s surface at a
particular point. It defines the boundary between
Earth and sky.
Hour Angle
An angle measured westward from the observer's
meridian to the meridian that contains the
direction to a celestial object.
HPOP (High Precision Orbit Propagator)
An orbit generator that can generate orbits for a
wide variety of Earth satellites with accuracy on
the order of 12 meters per orbit or better. [Addon Module]
Inclination
The angle between the orbit plane and the inertial
equatorial plane. It is also measured as the angle
between the orbital angular momentum vector and
the celestial pole.
Inclined Orbit
Any non-equatorial orbit of a satellite.
Insert
[Files menu]. Use this command to insert a
previously defined object into the current
scenario.
A-7
Glossary of Terms
Instance
A specific occurrence of an object class. For
example, the ERS1 vehicle is one instance of the
vehicle class.
Latitude
The angular distance north or south from the
equator of a point on the Earth’s surface,
expressed in degrees.
J2 Perturbation
An analytical orbit propagator that accounts for
secular variations in the orbital elements due to the
first order Earth oblateness effects.
Line of Sight
Geometric direction in which two objects have
direct visibility of each other.
J4 Perturbation
An analytical orbit propagator that accounts for
secular variations in the orbital elements due to
first and second order Earth oblateness effects.
J2000 Coordinate System
Specifies that X and Z axes point toward the mean
vernal equinox and mean rotation axes of the Earth
at January 1, 2000 at 12:00:00.00 UTC. J2000.0 =
2000 January 1.5 = JD 2451545.0 TDB
(Barycentric Dynamic Time).
Julian Date (JD)
The sequential day count reckoned consecutively
beginning on 1 January 4713 BC. The Julian Date
for 1 January 1990 was 2,446,892.
Keplerian Elements
A set of six parameters which together describe
the shape and orientation of an elliptical orbit
around the Earth, as well as the position of a
satellite in that orbit at a given epoch. The usual
elements are: Right Ascension of the Ascending
Node, Argument of the Perigee, Mean Anomaly,
Semi-Major Axis, Inclination and Eccentricity.
Kepler's Equation
An equation that relates Mean Anomaly (M),
Eccentric Anomaly (E) and Eccentricity (e),
namely:
M = E - e sin E
The equation is used to calculate E for given M
and e. It is possible to calculate the True Anomaly
from E.
Keyboard Accelerators
See Accelerator Keys.
A-8
Local Apparent Time
The hour angle between an observer’s local
meridian and the meridian passing through the
true Sun. A Sundial reads local apparent time.
Using this time reference, the Sun is at its highest
elevation at noon.
Local Satellite Time
The time corresponding to a satellite’s position in
its orbit relative to the Sun. When the satellite
crosses the projection of the Sun vector onto the
orbit plane on the side of the orbit nearest the Sun,
it is satellite noon. When the satellite crosses the
projection of the Sun vector onto the orbit plane
on the side of the orbit farthest from the Sun, it is
satellite midnight.
Local Gregorian
Local time zone date and time expressed in
standard Gregorian format (1 Nov 1997
00:00:00.0000).
Local Julian
Local time zone date and time expressed in day-ofyear format (306/97 00:00:00.0000).
Longitude
Angular distance along the equator from the
Greenwich meridian to the point of interest.
Although the convention is to measure this angle
from 0° to 360° eastward, longitudes are often
expressed -180° to +180° or 180° West to 180°
East.
Loop Time
Time at which animation loops back to the Start
Time specified.
Satellite Tool Kit®
Glossary of Terms
Lunar Exclusion Angle
Minimum angle between the line of sight from the
object to the object of interest and the line of sight
from the object to the Moon for which access is
considered valid.
Major Axis of an Ellipse
The longest diameter of the ellipse, which passes
through the center and both focal points.
Magnitude
The brightness of a celestial body as expressed on
a logarithmic scale. Magnitude increases for fainter
objects so that a magnitude 1 object is brighter
than a magnitude 2 object.
Map Attributes
>Scenario: Graphics Properties] Controls the
display of data such as orbit paths, object names,
ground tracks, and other satellite data. Attributes
also controls the display of the tool bar at the top
of the Map window and selection options.
Map Background
Scenario: Graphics Properties] Controls the
display of background image files or “texture” to
display in the Map window.
Map Details
Scenario: Graphics Properties] Controls the
display of land mass and other map features such
as the display of latitude and longitude lines in the
background and the image resolution of the map.
Map Projection
Controls the way in which the three-dimensional
(3-D) globe is presented in the Map window.
Map
Maps provide a geographic reference for a
scenario’s objects. The objects within a scenario
are related by time to a map.
Mass Unit
Specifies the unit of measure to be used when
referring to mass. Two options are available:
kilograms and pounds mass (not weight).
®
Satellite Tool Kit
Mean Anomaly
The angle measured from perigee of a hypothetical
body moving with a uniform speed that is equal to
the mean motion. It is the product of the mean
motion of the spacecraft and the interval of time
since it passed perigee. T is the orbital period and t
is the time past periapsis:
M=
2π ⋅ t
(radians)
T
Mean Solar Time or Universal Time (UT)
Time measured with reference to the motion of a
fictitious body called the Mean Sun, which moves
at a constant rate. Another way to state this
assumption is that the Earth moves in a circular
orbit around the sun, and that the axis of rotation
is perpendicular to the orbital plane (ecliptic). The
time interval between two meridian crossings of
the Mean Sun is exactly one solar day. Due to the
combined effects of the eccentricity of the Earth's
orbit and the tilt of the Earth’s rotation axis, the
real sun arrives at our local meridian a little early at
certain times of the year, and a little late at other
times. The difference between real solar time and
mean solar time is called the Equation of Time.
Mean Equinox True Equator Coordinate
System
Specifies that the X and Z axes point toward the
mean vernal equinox and true rotation axis of the
Orbit Epoch date specified.
Mean Motion
The uniform rate of the satellite in a circular orbit
of the same period, typically expressed as degrees
or radians per second, or as revolutions per day. T
is the orbital Period:
n=
2π
(radians / sec)
T
Mean Motion Dot
The time rate of change of mean motion indicating
the degree to which perturbation forces acting on
the satellite are changing the size of the orbit.
A-9
Glossary of Terms
Mean of Date Coordinate System
An inertial coordinate frame in which the direction
of the X axis is defined by the mean vernal
equinox and the Z axis is defined by the mean spin
axis of the Earth at the time of the state vector.
The term Mean indicates that precession is
accounted for but nutation is not.
Mean of Epoch Coordinate System
An inertial coordinate frame in which the direction
of the X axis is defined by the mean vernal
equinox and the Z axis is defined by the mean spin
axis of the Earth at a user-specified epoch. The
term Mean indicates that precession is accounted
for but nutation is not.
Mercator
Projection can be thought of as being
mathematically based on a cylinder tangent at the
equator. Any straight line is a constant-azimuth
line, which is also called a loxodrome or rhumb
line. The north and south poles cannot be shown
in this rectangular projection since they are at
infinite distance.
Meta Key
A special keyboard key that typically has a unique
shape (such as the diamond on the Sun
workstation Meta key) or a unique word (such as
the Error! Not a valid filename. key on the Dec
and IBM workstation). Used in key combinations
for accelerator keys.
Miller
Rectangular projection constructed to provide an
alternative to the Mercator projection. The two
projections are similar near the equator but the
Miler projection avoids some of the exaggeration
in scale near the poles.
Mixed Spherical
A variation of the spherical coordinate system that
combines Earth-fixed position parameters with
inertial velocity parameters.
A-10
Mollweide
Equal and pseudo-cylindrical projection showing
the Earth in an ellipse with the equator twice as
long as the map’s actual meridian.
Motion Dot Dot
The second derivative of mean motion and first
derivative of motion dot. This quantity indicates
the degree to which the change in the size of the
orbit is accelerating due to perturbative effects on
the spacecraft.
MSGP4 Propagator
Used with two-line mean element sets. Considers
Earth oblateness, solar and lunar gravitational
effects, and resonance effects using a mean drag
model.
Nadir
The point on the celestial sphere directly beneath a
given position or observer and diametrically
opposite the zenith. Also the direction from an
object towards the center of the central body.
Node Rotation
A rotation of the orbital plane caused by the nonspherical shape (oblateness) of the Earth. This
precessional motion is similar to that of a simple top: the
normal to the orbital plane sweeps out a cone shaped
surface in space with a semi-vertex angle equal to the
inclination i. As the orbit precesses, the line of
intersection of the equator and the orbital plane (the line
of nodes) rotates westward for a posigrade orbit and
eastward for a retrograde orbit.
Object
An STK component capable of being manipulated.
In STK, objects are scenarios, vehicles, facilities,
targets, area targets, stars, planets, and sensors.
Open
[Files menu] Insert a previously saved scenario
into the current STK session. Only one scenario
can be open at any given time.
Satellite Tool Kit®
Glossary of Terms
Options Menu
These menus allow the user to select one and only
one item from a list that appears when you click
and hold the associated menu button.
Orbit
The gravitationally bound path followed by an
object around a celestial body.
Orbital Elements
The set of parameters that describe the size, shape,
and orientation of an orbit in inertial space.
Orthographic
Projection is geometrically based on a plane
tangent to the Earth. The point of projection is at
infinity. Directions from the center of the map
projection are true.
Osculating Orbit
The orbit along which a satellite would move if all
perturbing accelerations were removed at a
particular time. At that time, or Epoch, the
osculating and true orbits are in contact. It is the
osculating orbit – not the true, perturbed orbit –
for which the Keplerian elements are used.
Parallax
The apparent displacement of an observed object
due to a change in the position of the observer.
Pass Break
[Vehicle:Basic Properties] The point at which a
pass is considered to commence. Either the
ascending or descending node of the orbit.
Passes
A pass is a complete orbit of a satellite around the
Earth between successive node crossings.
Path
[Vehicle:Basic Properties] The route along which an
object moves.
Periapsis
The point in an elliptical orbit that is closest to the
gravitational center of the system comprising the
primary body and the satellite. In Earth-based
systems, the periapsis is called the perigee.
Perigee
The point in the orbit of a satellite orbiting the
Earth that is closest to the gravitational center of
the Earth.
Perigee Altitude
Altitude of the perigee of an orbit where perigee is
defined as the point in the orbit which is closest to
the center of the central body..
Period (T)
The time required for a satellite to complete one
revolution around the center of gravity.
Persistence
Length of time a sensor’s footprint remains visible.
Perspective
Projection of the Earth as a sphere from a userspecified viewing altitude.
Perturbation
Deviation of a satellite from true elliptical motion,
caused by disturbing accelerations due to the nonspherical shape of the Earth, influence of sun and
moon, drag and solar radiation pressure.
Pitch
A rotation about the Y axis of a reference
coordinate system. This reference coordinate
system can be a local system moving with the
object, a body-fixed coordinate system or an
inertial coordinate system. Pitch is defined relative
to the inertial coordinate system within STK.
Planet
A solar system object that orbits around the Sun. The
word planet originates from the Latin for “wanderer.”
Penumbra
That portion of a shadow in which the Sun is seen
as partially obscured.
®
Satellite Tool Kit
A-11
Glossary of Terms
Posigrade Orbit
An orbit in which the projection of the satellite's
position on the Earth's equatorial plane revolves in the
direction of the rotation of the Earth. The inclination
of a posigrade orbit is less than 90 degrees.
Precession
Rotation of the orbital plane caused by the nonspherical shape (oblateness) of the Earth.
Precessional motion is similar to that of a simple
top: the normal to the equatorial plane sweeps out
a cone shaped surface in space with a semi-vertex
angle equal to the inclination i. As the orbit
precesses, the line of intersection of the equator
and the orbital plane (line of nodes) rotates
westward for a posigrade orbit and eastward for a
retrograde orbit.
Print Setup
[Files menu] Set print parameters such as
orientation, width/height, layout, output device,
color mode, background, and file format.
Properties Menu
Pull-Down Menu that allows the user to set basic,
graphics, and constraints properties for the selected
object.
Pull-down Menu
Click the menu of your choice in the menu bar at the
top of the Browser window to display pull-down
menus of available options. Four pull-down menus are
available: Files, Properties, Tools, and Help.
Radio Button
Diamond-shaped button that allow the user to
select one and only one item in a group of radio
buttons.
Range
The linear distance between two points.
Range Rate
The component of the spacecraft velocity in the radial
direction either toward or away from the observer.
Real-Time
Run animation in real-time in accordance with the
user’s on-board real-time clock.
Rectangular Coordinate System
A coordinate system in which positions are
specified by distances from the origin along the
three mutually orthogonal axes.
Refresh Delta
Time lapse between refresh updates. Actual refresh delta
is limited by the minimum time necessary to redraw the
screen and varies with processor performance, graphics
hardware options, and scenario complexity.
Remove
[Files menu] Use this command to remove an object
from the current scenario.
Resolution
[Sensor:Basic/Constraints Properties] The degree to
which two closely spaced objects can be distinguished as
separate. Resolution increases with increasing aperture;
larger antenna and larger telescopes have better resolution
than smaller ones.
Retrograde Orbit
An orbit in which the projection of the satellite's
position on the Earth's equatorial plane revolves in
the direction opposite to that of the rotation of
the Earth. The inclination of a retrograde orbit is
greater than 90 degrees.
Right Ascension
Angle measured in the inertial equatorial plane
from the inertial X axis in a right-handed sense
about the inertial Z axis.
Right Ascension of Ascending Node (RAAN)
The angle measured in the inertial equatorial plane from
the inertial X axis to the ascending node of the satellite’s
orbit in a right-handed sense about the inertial Z axis.
Rocket
Defines a vehicle following an elliptical path that
begins and ends at the Earth’s surface.
Rate
A change in some quantity over time.
A-12
Satellite Tool Kit®
Glossary of Terms
Roll
A rotation about the X axis of a reference
coordinate system. This coordinate system can be
a local system moving with the object, a bodyfixed coordinate system or an inertial coordinate
system. Roll is defined relative to the inertial
coordinate system in STK.
Round-trip Delay Time
The time required for a signal to travel from an Earth
station via a satellite to another Earth station
(approximately 250 milliseconds for a geostationary
satellite).
Save As
[Files menu] Use this command to save the current
object under anew name.
Save
[Files menu] Use this command to overwrite the
original object file so that it includes any changes
made since last saved.
Scenario
The highest-level object within STK. Scenarios
contain other objects and becomes the outline for
a proposed series of events that can be visualized.
Semimajor Axis
Half the distance between the two most distant
points on an ellipse. For a circle, the semimajor
axis is the same as the radius of the circle.
Sensors
Beam of some shape that points in a particular
direction. Sensors can represent transmitting,
receiving, or sensing devices with associated
attributes and/or constraints. They can also be
attached to a vehicle, facility, or target. They can
also be used to define areas such as a satellite’s
field of view of constraint, or areas such as a
minimum elevation for a target in a valley.
Sidereal Time
The time required for the Earth to rotate once on
its axis relative to the stars, equal to 23h 56m 4s of
ordinary mean solar time. A sidereal day consists
of 24 sidereal hours and begins when the Vernal
®
Satellite Tool Kit
Equinox crosses the Greenwich meridian. Sidereal
time is therefore equal to the Hour Angle of the
Vernal Equinox.
Sinusoidal
Projection is mathematically based on a cylinder
tangent on the equator. May have several central
meridians.
Solar Beta Angle
The signed angle of the vector to the Sun relative
to the orbital plane. The signed angle is positive
when the vector to the Sun is in the direction of
the orbit normal. The orbit normal is parallel to
the orbital angular momentum vector, which is
defined as the cross-product of the inertial
position and velocity vector.
Solar Exclusion Angle
Minimum angle between the line of sight from the
object to the object of interest and the line of sight
from the object to the Sun for which access is
considered valid.
Spherical Coordinate System
A coordinate system in which positions are
specified as a radial distance from the origin and
two angles relative to a fundamental plane.
Spin Offset
Establishes the spin angle from some reference
point at epoch.
SSC (Space Surveillance Catalog) Number
Number assigned to satellites for purposes of
identification.
Star
A fixed point on the celestial sphere representing
members of the solar neighborhood and
characterized by their position and brightness.
Start Time
Parameter that specifies when a specified function
is to begin.
A-13
Glossary of Terms
Status Area
Area located along the bottom of the Map window
that displays latitude and longitude values,
animation time, and status messages (such as
paused and inactive).
Step Count
Also referred to as Step Size. For orbit
propagation, step size is the time step used in
calculating ephemeris points. In animation, step
size determines how much time passes between
each picture update.
Step Size
See Step Count.
Stereographic
Projection is geometrically projected onto a plane.
The point of projection is on the surface of the
sphere opposite the point of tangency. Directions
from the center of the projection are true.
.stkrc File
[PC STK Run Control File] File that identifies the
STK database and STK home directories as well as
certain defaults set for the STK session.
.stkrc3 File
[UNIX STK Run Control File] File that identifies
the STK database and STK home directories as
well as certain defaults set for the STK session.
Stop Time
Parameter that specifies when a specified function
is to end.
Subsolar Point
The point on the Earth directly below the Sun.
Sun Elevation Angle
The elevation of the Sun relative to the selected
object.
Sun Lighting
[Vehicle:Graphics Properties] Controls the way
available Sunlight conditions for the scenario are
graphically displayed in the Map window.
A-14
Swath
[Tools menu] Delineate the visible areas for the
system or the points on the ground from which
the vehicle or sensor can be seen.
Target
Point of interest on the ground that does not
move.
Text Annotation
[Scenario:Graphics Properties] Allows the user to
specify text to display in the Map window at a
specified latitude and longitude and/or at a
specified X,Y coordinate.
TDRS (Tracking and Data Relay Satellite)
Special satellite used for communication by the
government and military. Used heavily by NASA
during shuttle missions to provide a
communications link when the shuttle is out of
view of a ground station.
Time Period
>Scenario:Basic Properties] Defines the general
time span (a range of several hours, days, or
weeks) for analysis and propagates the orbits for
all satellites currently loaded in the scenario.
Time Step
The time lapse between screen updates for
animation.
Time Units
Specify the unit of measure to be displayed when
referring to time. Options are: seconds, hours,
minutes and days.
Toggle Button
[UNIX platforms] Square-shaped button that
allows the user to flip between two opposite
conditions. When a toggle button appears pushed
in, the option is ON.
Tool Bar
Area located along the top of the Map window
that contains animation command buttons such as
Animate Forward, Animate Reverse, Increase
Time Step, Decrease Time Step, Pause, Reset, Step
Satellite Tool Kit®
Glossary of Terms
Forward, Step Reverse, Zoom In, Zoom Out,
Measure, and Resize To Aspect Ratio. Also
contains a tool bar message window that displays a
text description of any button on the tool bar
when the user moves the cursor over a button.
Tools Menu
Pull-down menu that allows the user to perform
specialized functions such as defining and
displaying accesses, lighting conditions,
vehicle/sensor swaths, and Walker constellations.
Tools are also available for creating reports and
graphs, and importing satellites.
Topocentric
A coordinate system originating at a point on the
Earth. The axes are defined so that x is in the local
north direction, y is in the local east direction and
z is along the inward normal to the surface.
Torque
The vector cross-product of force and the distance
from the center of mass at which the force is being
applied. An applied torque produces an angular
acceleration about the object’s center of mass.
True Anomaly
The angle from the eccentricity vector to the
object position vector, measured in the direction
of object motion.
True of Date Coordinate System
An inertial coordinate frame in which the direction
of the X axis is defined by the true vernal equinox
and the Z axis is defined by the true spin of the
Earth at a user-specified epoch. The term True
indicates that both precession and nutation have
been accounted for.
True of Epoch Coordinate System
An inertial coordinate frame in which the direction
of the X axis is defined by the true vernal equinox
and the Z axis is defined by the true spin of the
Earth at the time of the state vector. The term
True indicates that both precession and nutation
have been accounted for.
®
Satellite Tool Kit
Turn Radius
Curvature of the arc between the current waypoint
and the next.
Two-Body
Keplerian motion propagator considers the Earth
to be a point mass with no perturbations.
Two-line Element (TLE) Set
A set of parameters that provides for accurate
reconstruction of ephemeris for an extended
period of time.
Umbra
That portion of a shadow in which the Sun is seen
as entirely obscured.
Units
[Scenario:Basic Properties] Establish the default
settings for all units of measure used in a scenario.
Universal Time (UT)
Local mean solar time on the Greenwich meridian,
also called Greenwich Mean Time (GMT) or Zulu
Time (Z).
UTC Gregorian
Universal Coordinated Time displayed in
Gregorian format (1 Nov 1997 00:00:00.0000).
UTC Julian
Universal Coordinated Time displayed in day-ofyear format. (306/97 00:00:00.0000).
Vehicle
Movable land, sea, air, or space objects. Those
vehicles that move within the atmosphere are
considered nonorbiting vehicles; those that move
outside the atmosphere are considered orbiting
vehicles.
Velocity
A vector describing the speed and direction of an
object in motion.
A-15
Glossary of Terms
Vernal Equinox Direction
The direction toward a point in the constellation
of Aries. On the first day of spring, a line joining
the center of the Earth and the center of the sun
points in this direction. This line is the
intersection of the Earth's equatorial plane and the
plane of the Earth's revolution around the sun
(ecliptic plane). The vernal equinox direction is
used as the x-axis for an astronomical reference
system. (To be more precise, the reference frame is
based on the vernal equinox for a particular
epoch.)
Walker Constellation
Group of satellites that are in circular orbits and
have the same period and inclination.
A-16
X Real-time
The number of times faster than real time the
animation should run.
Yaw
A rotation about the Z axis of a reference
coordinate system. This coordinate system can be
a local system moving with the object, a bodyfixed coordinate system or an inertial coordinate
system. Yaw is defined relative to the inertial
coordinate system within STK.
Zoom
Change magnification without losing focus.
Satellite Tool Kit®
APPENDIX B
DEFINING
CUSTOM SENSOR
PATTERNS
Overview
This appendix explains how to define a custom sensor pattern for a vehicle,
facility, or target in STK. There are three different methods for defining
custom sensor patterns in STK. In the following sections, the same custom
sensor pattern is created using each method. Once the pattern has been
defined, it is saved to a pattern file. STK reads the description when the file is
referenced by a sensor attached to an object.
The example used in this appendix is to create a sensor pointing off the right
side of the vehicle with a beam from 40° to 50° off nadir. The sensor also
sweeps forward and aft 30°. It is assumed that the vehicle’s attitude is such
that the vehicle X axis is along the velocity direction, which means that the
custom sensor pattern is centered around a vehicle azimuth of 90°. The
sensor is designed so that the reference direction (boresight) is along nadir
and, therefore, is outside of the pattern.
®
Satellite Tool Kit User’s Manual
B-1
Defining Custom Sensor Patterns
It is important to note that the accuracy of computations performed using
custom sensors is directly related to the number of points used to describe
the pattern. It is generally better to spend additional time up front to
generate a well-defined pattern than to be uncertain of the fidelity of the
results.
Chapter Contents
The Reference Plane Format ........................................................................B-2
The Az-El Mask Format .................................................................................B-7
The Angle-Off-Boresight Format...................................................................B-9
The Reference Plane Format
In the reference plane format, the custom sensor pattern is defined by the
intersection of the sensor’s projection with a plane perpendicular to the
sensor reference direction (boresight) at a specified distance from the origin
of the sensor. The intersection is described in polar coordinates.
1. Define the geometry of the problem graphically. In Figure B-1, α and β define
the sensor elevation sweep angles from nadir, in this case 40° and 50°
respectively. The angles δ and γ define the forward and aft sweep, in this case
both 30°.
B-2
Satellite Tool Kit® User’s Manual
Defining Custom Sensor Patterns
Figure B-1. The desired relative geometry of the satellite and the custom
sensor pattern.
Velocity Vector
Ref
Distance
α
β
δ
γ
Forward Sweep
aft Sweep
nadir
The location of the reference plane is measured relative to the sensor location and is
different than the distance from the sensor to the surface of the Earth.
1RWH
2. Using a piece of polar coordinate graph paper, diagram the sensor as it
would appear in the reference plane. Use the center of the plot as the
origin of the vehicle nadir vector and 0° of the polar plot to be in the
direction of the vehicle X axis (vehicle velocity direction). Refer to Figure
B-2.
®
Satellite Tool Kit User’s Manual
B-3
Defining Custom Sensor Patterns
Figure B-2. Polar coordinate paper showing the sensor coordinates
0.0
45.0
315.0
δ
270.0
150
125
100
75
50
25
90.0
γ
225.0
135.0
180.0
3. The radius values for the polar coordinates describing the custom sensor
pattern are obtained by projecting the sweep angles, α and β, onto the
reference plane. To do this, assign an arbitrary fixed distance of the
reference plane from the vehicle. In this example, a value of 100 is used.
Some trigonometry is used to calculate the radius values from α and β. To
calculate r, use the following equation:
tan θ=
B-4
1RRQUKVG
#FLCEGPV
θ
Satellite Tool Kit® User’s Manual
Defining Custom Sensor Patterns
where Opposite equals r or the length of the line from the vehicle nadir
vector to the sensor pattern edge, in the reference plane, and Adjacent
equals the reference plane distance. For this example, the reference
distance is 100 units.
Your calculations would be:
α = 40 0
tan 40 =
β = 50 0
r
100
r = tan 40 × 100
r = 8391
.
tan 50 =
r
100
r = tan 50 × 100
r = 119175
.
4. Once you have projected the sensor pattern onto the graph paper, read off
a suitable number of points to describe the shape of the pattern. Each
point is specific by r, the radial distance from the center, and theta, the
angle measured from straight up, clockwise. Table 1 below, shows the
polar coordinates derived from our example:
Table B-1. Polar coordinates
®
r
theta
83.91
60.0
83.91
70.0
83.91
80.0
83.91
90.0
83.91
100.00
83.91
110.0
83.91
120.0
119.175
120.0
119.175
110.0
Satellite Tool Kit User’s Manual
B-5
Defining Custom Sensor Patterns
r
theta
119.175
100.0
119.175
90.0
119.175
80.0
119.175
70.0
119.175
60.0
5. Create the Custom Pattern file. Now that you have the polar coordinates
for your custom sensor pattern, create a new file in your STK Database
(STKdb) directory. The file name should be a descriptive name of 20
characters or less.
6. Once the file has been created, open it using a standard text editor and
enter the information in the format shown in the sample custom sensor
pattern file below. Notice that the first point is repeated as the last point so
that the sensor pattern is closed. When you finish, close and save the file.
We recommend using a convention such as a ‘.Pattern’ extension for sensor pattern files.
+LQW
Listing B-1. STK Custom Pattern File
stk.v.3.0
ReferenceDistance 100.0
NumberPoints 15
PatternData
83.91
60.0
83.91
70.0
83.91
80.0
83.91
90.0
83.91
100.00
83.91
110.0
83.91
120.0
119.175 120.0
119.175 110.0
119.175 100.0
119.175 90.0
119.175 80.0
119.175 70.0
119.175 60.0
83.91
60.0
EndPatternData
B-6
Satellite Tool Kit® User’s Manual
Defining Custom Sensor Patterns
The Az-El Mask Format
The Az-El Mask format provides a convenient way to account for obscura
for a target or facility. In this format, the custom sensor pattern is defined by
the angle between the edge points of the sensor pattern and a plane
perpendicular to the sensor reference direction and measured as positive
toward the reference direction. When sensors using this type of custom
pattern are attached to targets or facilities, the sensor reference direction is
aligned with the local zenith direction.
Figure B-3. Definition of the elevation angle.
elevation
Generate the custom pattern for the example using a polar diagram similar to the
one in the reference pane format. The azimuthal angles on the plot now represent
azimuth in the facility’s or target’s local horizon plane with 0° being in the direction
of north. The concentric circles on the plot represent elevation angles.
®
Satellite Tool Kit User’s Manual
B-7
Defining Custom Sensor Patterns
Figure B-4. Polar projection for the Az-El Mask format.
0.0
45.0
315.0
δ
0.0
40
50
60
70
γ
225.0
135.0
180.0
1RWH
The angle α = 40° off the boresight becomes the line along the 50° elevation contour and
the angle β = 50° off the boresight becomes the line along the 40° elevation contour.
The resulting pattern file for the Az-El Mask format is then created using the
edge points in the polar diagram and making the first and last points the same
to close the pattern.
Listing B-2. Az-El Mask Format
Stk.v.3.0
NumberPoints 27
AzElMaskData
60
65
70
B-8
40
40
40
Satellite Tool Kit® User’s Manual
Defining Custom Sensor Patterns
75
40
80
40
85
40
90
40
95
40
100
40
105
40
110
40
115
40
120
40
120
50
115
50
110
50
105
50
100
50
95
50
90
50
85
50
80
50
75
50
70
50
65
50
60
50
60
40
EndPatternData
The Angle-Off-Boresight Format
In the Angle-Off-Boresight format, the custom sensor pattern is defined by
the angle between the edge points of the sensor and the boresight direction.
The custom pattern can be determined from a polar diagram where the
concentric circles are lines of constant angle from the boresight. The AngleOff-Boresight format is an alternative to the Reference Plane format and
provides for the input of the elevation sweep angles and the forward and aft
sweep angles directly.
®
Satellite Tool Kit User’s Manual
B-9
Defining Custom Sensor Patterns
Figure B-5. Polar projection for the Angle-Off-Boresight format
0.0
45.0
315.0
δ
70.0
60
50
40
30
20
10
90.0
γ
225.0
135.0
180.0
The pattern file is now created using the edge points and making the
first and last points the same to close the pattern.
Listing B-3. Angle-off-boresight pattern
Stk.v.3.0
NumberPoints 27
HalfAngleAzimuthData
40
40
40
40
B-10
60
65
70
75
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Defining Custom Sensor Patterns
40
80
40
85
40
90
40
95
40
100
40
105
40
110
40
115
40
120
50
120
50
115
50
110
50
105
50
100
50
95
50
90
50
85
50
80
50
75
50
70
50
65
50
60
40
60
EndPatternData
®
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Defining Custom Sensor Patterns
127(6
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Satellite Tool Kit® User’s Manual
Appendix C
IMPORTING FILES
INTO STK
Overview
STK users can create external files of data that can be imported into STK and
used to provide reference data for an object. These objects must conform to
the appropriate file format.
The sample files shown in this appendix are for illustrative purposes only. ,W LV QRW WKH
:DUQLQJ
SXUSRVH RI WKLV DSSHQGL[ WR LQGLFDWH WKH IXOO UDQJH RI FKRLFHV RU SRVVLELOLWLHV IRU D
JLYHQ REMHFW
External files must be arranged in blocks, called Keyword Groups, that are
set off with the word BEGIN and the group name (e.g., BEGIN Attitude)
at the start of the block and the word END and the group name (e.g., END
Attitude) at the end of the block. The information contained in the block
consists of keywords (e.g., NumberOfAttitudePoints) and values (e.g.,
3) that are called keyword phrases. Therefore, a keyword phrase would be:
NumberOfTorques
20
You can currently import data from the following types of external files:
Satellite Tool Kit® User’s Manual
C-1
Importing Files into STK
♦
.xpm files
♦
external ephemeris files
♦
attitude files
♦
torque files
♦
az-el files
♦
STK database files
♦
planet files
♦
custom sensor files
♦
solar flux files
Chapter Contents
Overview .....................................................................................................C-1
Attitude File Format......................................................................................C-3
Az-El File (.aem) Format................................................................................C-8
Custom Sensor File Format ..........................................................................C-9
Ephemeris File Format (.e) ...........................................................................C-9
Planetary Ephemeris File (.pe) Format....................................................... C-17
Torque File (.tq) Format ............................................................................ C-18
Color Bitmap/Pixmap (.bmp/.xpm) File Format ........................................ C-19
Database File Formats............................................................................... C-20
Satellite Database................................................................................. C-20
TLE File Format..................................................................................... C-26
City Database....................................................................................... C-29
Facility Database .................................................................................. C-32
Star Database....................................................................................... C-34
Solar Flux Files ........................................................................................... C-38
C-2
Satellite Tool Kit® User’s Manual
Importing Files into STK
Attitude File Format
It is often necessary to import external attitude information into STK to
model certain unique circumstances. The attitude information describes a
rotation from the ECI J2000 coordinate frame to the vehicle body frame.
Keywords aren’t case sensitive.
All angles are in degrees. All times are specified in seconds relative to the scenario epoch
defined within the file.
1RWH
There are five formats for specifying the rotation between these two
coordinate frames; all share certain common characteristics. The first line of
each file contains the application version number (e.g., stk.v.3.0). The
primary section of each file is set off by the Keyword Group name that
defines the data contains within the group (i.e., BEGIN Attitude at the
beginning of the Keyword Group and END Attitude at the end of the
Keyword Group). In between these beginning and end statement is the data
that defines the object.
Inside the attitude section are several keywords to identify the scenario
epoch time and the attitude format. These are described below.
Table C-1. Keywords for Attitude
Keyword
Format
Description
ScenarioEpoch
dd mmm
yyyy
hh:mm:ss.s
Specifies the epoch time for the attitude
points. For example, if the scenario epoch is
1 Jan 1997 00:00:00.0, a time of 5.5
for a particular attitude point would
correspond to a time of 1 Jan 1997
00:00:05.5.
This entry must precede actual attitude data.
Satellite Tool Kit® User’s Manual
C-3
Importing Files into STK
Keyword
Format
Description
NumberOfAttitudePoi
nts
nnnnn
Specifies the number of attitude points to
follow. For example, if you enter 1000 here,
1000 attitude points would be included.
This entry must precede actual attitude data.
Sequence
nnn
Specifies the rotation sequence when the
attitude is specified via Euler or Yaw-PitchRoll angles. There are 12 possible sequences
for Euler angles where 1-2-3 correspond to
rotations about the X, Y and Z axes
respectively. The default Euler sequence is 31-3
There are six possible sequences for YawPitch-Roll where 1-2-3 correspond to
rotations about the inertial X, Y and Z axes
respectively. The default sequence is 3-2-1 or
Yaw-Pitch-Roll.
AttitudeTimeQuaterni
ons
tttttt.ttt
q1
q2
q3
Specifies that the data points following are
unit length quaternions where ttttt.ttt
is the time in seconds relative to the epoch
and q1 through q4 specify the four elements
of a quaternion where q4 is the scalar
component. For example,
q4
123.456
0.0678338906
0.0000000000
0.0000000000
0.9976966289
The AttitudeTimeQuaternion format doesn’t
require the Sequence keyword since
quaternions don’t have a rotation sequence.
C-4
Satellite Tool Kit® User’s Manual
Importing Files into STK
Keyword
Format
Description
AttitudeTimeEuler
Angles
tttttt.ttt
Specifies that the data points following are
Euler angles where ttttt.ttt is the time
in seconds relative to the epoch and rotA
through rotC specify the three Euler
angles through which you wish to rotate.
rotA
rotB
rotC
The first rotation is by rotA degrees about
the first axis specified by the Sequence
keyword. The second rotation is by rotB,
and the third by rotC. For example:
123.456
10.0
20.0
30.0
The
format
AttitudeTimeEulerAngles
requires that a Sequence keyword precedes
the angles so that the axes of rotation can be
specified.
AttitudeTimeYPR
Angles
tttttt.ttt
yaw
pitch
roll
Specifies that the data points following are
rotation angles about the inertial axes where
ttttt.ttt is the time in seconds relative
to the epoch and yaw, pitch and roll
specify the rotation angles about the inertial
Z, Y and X axes, respectively. For example,
123.456
10.0
20.0
30.0
The AttitudeTimeYPRAngles format requires
that a Sequence keyword precedes the
angles so that the axes of rotation can be
specified..
Satellite Tool Kit® User’s Manual
C-5
Importing Files into STK
Keyword
Format
Description
AttitudeTimeECIVector
ttttt.ttt
Specifies that the data points following
specify a vector in the ECI frame where
ttttt.ttt is the time in seconds relative
to the epoch and v1 through v3 are the
three components of the vector.
v1
v2
v3
This format is primarily used for
atmospheric vehicles where the pointing
direction is known and orientation about the
pointing vector may be assumed. The vector
specifies the orientation of the body X axis
in the ECI frame. The body is then rotated
to constrain the body Z axis to provide the
minimum angle relative to nadir. For
example,
123.456
1.0
0.0
0.0
The AttitudeTimeECIVector format doesn’t
require a Sequence keyword.
C-6
Satellite Tool Kit® User’s Manual
Importing Files into STK
Keyword
Format
Description
AttitudeTimeECF
Vector
ttttt.ttt
Specifies that the data points following
specify a vector in the ECF frame where
ttttt.ttt is the time in seconds relative
to the epoch and v1 through v3 are the
three components of the vector.
v1
v2
v3
This format is primarily used for rockets
where the pointing direction is known but
the orientation about the pointing vector
may not be known. The vector specifies the
orientation of the body X axis in the ECF
frame. The body is then rotated to constrain
the body Z axis and provide the minimum
angle relative to nadir. For example,
123.456
1.0
0.0
0.0
The AttitudeTimeECFVector format doesn’t
require a Sequence keyword.
A sample AttitudeTimeQuaternion format is provided below for your
reference.
Listing C-1. Attitude File Format
stk.v.3.0
BEGIN Attitude
NumberOfAttitudePoints
ScenarioEpoch
3
1 Jan 1995 00:00:00.0
AttitudeTimeQuaternions
0.000 0.0000000000 0.0000000000 0.0000000000 1.0000000000
15.558 0.0678338906 0.0000000000 0.0000000000 0.9976966289
30.644 0.1333127632 0.0000000000 0.0000000000 0.9910740170
Satellite Tool Kit® User’s Manual
C-7
Importing Files into STK
END Attitude
Az-El File (.aem) Format
The data in an external az-el file should start at zero azimuth and go to an
azimuth of 360°. Elevation values can range from -90° to 90°. The format of
each data line is:
azimuth
elevation
A sample Az-El file is shown below.
Listing C-2. Sample Az-El File Format
stk.v.3.0
BEGIN AzElMask
NumberOfPoints
67
Begin AzElMaskData
0.0
5.0
6.0
7.0
8.0 8.0
9.0 9.0
10.0
11.0
12.0
13.0
14.0
15.0
20.0
25.0
27.5
.
.
.
267.5
C-8
5.0
5.0
6.0
7.0
10.0
9.0
8.0
7.0
6.0
5.0
5.0
5.0
7.5
22.5
Satellite Tool Kit® User’s Manual
Importing Files into STK
270.0
25.0
272.5
22.5
275.0
20.0
277.5
17.5
280.0
15.0
290.0
5.0
300.0
5.0
310.0
5.0
320.0
5.0
330.0
5.0
340.0
5.0
350.0
5.0
360.0
5.0
End AzElMask
Custom Sensor File Format
Please consult Appendix B: Custom Sensor Patterns to learn more about
creating a custom sensor pattern and file formats required.
Ephemeris File Format (.e)
It is often necessary to import external ephemeris information into STK to
model certain unique circumstances. The ephemeris information describes
the position and velocity of the vehicle.
There are three formats for specifying the position and velocity of the
vehicle; all share certain common characteristics. The first line of each file
contains the application version number (e.g., stk.v.3.0). The primary
section of each file is set off by the Keyword Group name that defines the
data contains within the group (i.e., BEGIN Ephemeris at the beginning
of the Keyword Group and END Ephemeris at the end of the Keyword
Group). In between these beginning and end statement is the data that
defines the object.
Satellite Tool Kit® User’s Manual
C-9
Importing Files into STK
Inside the ephemeris section are several keywords to identify the
scenario epoch time and the ephemeris format. These are described
below.
Table C-2. Keywords for Ephemeris file format
Keyword
Format
Description
ScenarioEpoch
dd mmm
yyyy
hh:mm:ss.s
Specifies the epoch time for the
ephemeris points. For example, if the
scenario epoch is 1 Jan 1997
00:00:00.0, a time of 5.5 for a
particular ephemeris point would
correspond to a time of 1 Jan 1997
00:00:05.5.
This entry must precede actual ephemeris
data.
NumberOfEphemeris
Points
nnnnn
Specifies the number of ephemeris points
to follow. For example, if you enter 1000
here, 1000 ephemeris points would be
included.
This entry must precede actual ephemeris
data.
C-10
Satellite Tool Kit® User’s Manual
Importing Files into STK
Keyword
Format
Description
EphemerisECFTimePosVel
tttttt.ttt
Specifies that the data points that
follow are positions and velocities
in the ECF frame where
ttttt.ttt is the time in
seconds relative to the epoch, x
through z are the ECF positions
in meters and xdot through
zdot are the ECF velocities in
meters per second. For example,
123.456
1.0
2.0
3.0
0.5
0.6
x
y
z
xdot
ydot
zdot
0.7
EphemerisECITimePosVel
tttttt.ttt
x
y
z
xdot
Specifies that the data points following
are positions and velocities in the J2000
ECI frame where ttttt.ttt is the
time in seconds relative to the epoch, x,
y and z are the ECI positions in meters,
and xdot, ydot and zdot are the
ECI velocities in meters/sec.
ydot
123.456
zdot
1.0
2.0
3.0
0.5
0.6
0.7
Satellite Tool Kit® User’s Manual
C-11
Importing Files into STK
Keyword
Format
Description
EphemerisLLRTimePosVel
tttttt.ttt
Specifies that the data points following
are positions and velocities in an ECF
frame where ttttt.ttt is the time in
seconds relative to the epoch, lat,
lon and rad are the geocentric latitude,
longitude and radius (in degrees and
meters, respectively), and latdot,
londot, and raddot are the rates of
change of these parameters per second.
lat
lon
rad
latdot
londot
raddot
123.456
1.0
2.0
3.0
0.5
0.6
0.7
EphemerisLLATimePosVel
tttttt.ttt
lat
lon
alt
latdot
londot
altdot
Specifies that the data points following
are positions and velocities in an ECF
frame where ttttt.ttt is the time in
seconds relative to the epoch, lat,
lon and rad are the geocentric latitude,
longitude and altitude (in degrees and
meters, respectively), and latdot,
londot, and altdot are the rates of
change of these parameters per second.
123.456
1.0
2.0
3.0
0.5
0.6
0.7
C-12
Satellite Tool Kit® User’s Manual
Importing Files into STK
Keyword
Format
Description
EphemerisLLATimePos
tttttt.ttt
Specifies that the data points following
are positions and velocities in an ECF
frame where ttttt.ttt is the time in
seconds relative to the epoch, lat, lon and
alt are the geocentric latitude, longitude
and altitude (in degrees and meters,
respectively), and velocity is interpolated
from position information.
lat
lon
alt
123.456
1.0
2.0
3.0
EphemerisGeodeticLLR
TimePosVel
tttttt.ttt
lat
lon
rad
latdot
londot
raddot
Specifies that the data points following
are positions and velocities in an ECF
frame where ttttt.ttt is the time in
seconds relative to the epoch, lat is the
geodetic latitude (in degrees), lon and
rad are the geocentric longitude and
radius (in degress and meters,
respectively), and latdot, londot,
and raddot are the rates of change of
these parameters per second.
123.456
1.0
2.0
3.0
0.5
0.6
0.7
Satellite Tool Kit® User’s Manual
C-13
Importing Files into STK
Keyword
Format
Description
EphemerisLLRTimePos
tttttt.ttt
Specifies that the data points following
are positions and velocities in an ECF
frame where ttttt.ttt is the time in
seconds relative to the epoch, lat is the
geodetic latitude (in degrees), lon and
rad are the geocentric longitude and
radius (in degress and meters,
respectively), and velocity is interpoated
from position.
lat
lon
rad
123.456
1.0
2.0
3.0
EphemerisGeodeticLLA
TimePosVel
tttttt.ttt
lat
lon
alt
latdot
londot
altdot
Specifies that the data points following
are positions and velocities in an ECF
frame where ttttt.ttt is the time in
seconds relative to the epoch, lat is the
geodetic latitude (in degrees), lon and
alt are the geocentric longitude and
altitude (in degress and meters,
respectively), and latdot, londot,
and altdot are the rates of change of
these parameters per second.
123.456
1.0
2.0
3.0
0.5
0.6
0.7
C-14
Satellite Tool Kit® User’s Manual
Importing Files into STK
Keyword
Format
Description
EphemerisLLATimePos
tttttt.ttt
Specifies that the data points following
are positions and velocities in an ECF
frame where ttttt.ttt is the time in
seconds relative to the epoch, lat is the
geodetic latitude (in degrees), lon and
alt are the geocentric longitude and
altitude (in degress and meters,
respectively), and velocity is interpoated
from position.
lat
lon
alt
123.456
1.0
2.0
3.0
A sample ECITimePosVel format is provided below for your reference.
Listing C-3. ECITimePosVel File Format
stk.v.3.0
BEGIN Ephemeris
NumberOfEphemerisPoints 81
ScenarioEpoch 1 Feb 1997 00:00:00.0
EphemerisEciTimePosVel
0.000
4482020.588 6164585.645 2729927.393 -4547.234623
951.470332 413.978539
180.000 3612448.002 6260360.709 3667378.031 -5094.799967
111.016509 4981.283095
360.000 2655428.996 6204621.135 4516086.319 -5516.897019 728.292472 4430.320111
540.000 1634481.691 5999568.188 5256140.144 -5803.862975 1544.431356 3776.895453
720.000 574473.966 5651265.575 5870727.714 -5950.379934 2316.641762 3039.516766
900.000 -499160.298 5169344.113 6346549.050 -5955.453865 3026.155186 2238.552297
1080.000 -1561180.749 4566590.678 6674072.962 -5822.172445 3656.750499 1395.366976
1260.000 -2587239.838 3858453.389 6847641.465 -5557.286368 4195.125756 531.501142
Satellite Tool Kit® User’s Manual
C-15
Importing Files into STK
1440.000 -3554494.945 3062496.633 6865434.196 -5170.669349 4631.085339 -32.056590
1620.000 -4442116.708 2197837.759 6729313.077 -4674.714035 4957.560849 -1175.468744
1800.000 -5231686.802 1284592.763 6444571.853 -4083.715763 5170.495904 -1980.505402
1980.000 -5907486.937 343352.289 6019616.386 -3413.286064 5268.630747 -2730.858500
2160.000 -6456687.278 -605297.336 5465600.255 -2679.825521 5253.223006 -3412.327040
2340.000 -6869446.698 -1541199.542 4796037.111 -1900.073243 5127.737423 -4012.894060
2520.000 -7138939.400 -2444996.408 4026407.100 -1090.739409 4897.531535 -4522.719823
2700.000 -7261322.752 -3298442.157 3173770.169 -268.218800 4569.557398 -4934.076068
2880.000 -7235660.286 -4084665.462 2256394.786 551.622744 4152.092738 -5241.244174
3060.000 -7063811.956 -4788386.596 1293406.737 1353.600749 3654.508837 -5440.396800
3240.000 -6750301.443 -5396096.317 304459.508 2123.316980 3087.077539 -5529.478646
3420.000 -6302167.805 -5896203.448 -690574.686 2847.230851 2460.815868 -5508.098032
3600.000 -5728806.270 -6279157.561 -1671895.966 3512.710923 1787.363905 -5377.437281
3780.000 -5041800.589 -6537552.206 -2620053.781 4108.079054 1078.889481 -5140.186551
3960.000 -4254747.258 -6666212.808 -3516214.250 4622.658410 348.011787 -4800.502832
4140.000 -3383070.009 -6662271.858 -4342422.338 5046.835053
392.265087 -4363.993155
.
.
.
12780.000 2198116.617 -4297359.089 -6975286.537 5428.751874
4079.415361 -540.424566
12960.000 3148502.990 -3520073.536 -6998208.867 5111.591744
4542.840873 288.135972
13140.000 4031389.170 -2667417.179 -6871206.220 4679.511693
4914.960125 122.514746
13320.000 4826582.047 -1756815.646 -6594825.550 4138.440091
5185.004699 1944.832409
13500.000 5515207.181 -807491.784 -6172911.580 3497.126345
5343.847500 2736.385312
13680.000 6080228.073 159870.353 -5612720.047 2767.253486
5384.457342 3478.054485
13860.000 6506976.556 1123544.523 -4924947.255 1963.443438
5302.361661 4150.826122
14040.000 6783672.006 2061262.792 -4123656.465 1103.122498
5096.082509 4736.414937
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14220.000 6901901.712 2950788.969 -3226084.412 206.220628
4767.503483 5217.967451
14400.000 6857030.937 3770548.411 -2252316.806 -705.310130
4322.121510 5580.806890
END Ephemeris
Planetary Ephemeris File (.pe) Format
The date field that is used for planetary is Julian Ephemeris Date. Julian
Ephemeris Date is the Julian Date representation of Terrestrial Dynamical
Time (TDT) which is equal to Atomic Time (TAI) plus 32.184 seconds.
UTC differs from TAI by the number of leap seconds which have been
accumulated. The conversion between the Julian Date based on UTC and
Julian Ephemeris Date as of Jan 1, 1996 when 30 leap seconds have been
accumulated is:
Julian Ephemeris Date = Julian Date + (32.184 + 30) / 86400.0
There are three possible units values for this file: au/day, Km/sec, and m/sec.
These units specify the units in the data and are themselves designated by the
Units keyword.
The planetary ephemeris data is specified in a Sun-centered inertial
coordinate system for which the axes are in alignment with the J2000
coordinate system.
A sample planetary file is shown below.
Listing C-4. Sample Planetary Ephemeris File Format
stk.v.3.0
Begin Ephemeris
Units au/day
NumberOfEphemerisPoints 30
EphemerisJ2000SciJedPosVel
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2449652.500708 -3.1997092e+00
5.0124296e-13 -2.3437952e-13
2449653.500708 -3.1937244e+00
5.0022715e-13 -2.3396376e-13
2449654.500708 -3.1877337e+00
4.9921028e-13 -2.3354751e-13
2449655.500708 -3.1817370e+00
4.9819235e-13 -2.3313078e-13
2449656.500708 -3.1757343e+00
4.9717336e-13 -2.3271355e-13
2449657.500708 -3.1697255e+00
4.9615331e-13 -2.3229584e-13
.
.
.
2449678.500708 -3.0421783e+00
4.7448882e-13 -2.2341157e-13
2449679.500708 -3.0360406e+00
4.7344570e-13 -2.2298320e-13
2449680.500708 -3.0298971e+00
4.7240156e-13 -2.2255436e-13
2449681.500708 -3.0237479e+00
4.7135638e-13 -2.2212504e-13
-4.0216144e+00 -1.6458850e+00 8.0130291e-13 -4.0253524e+00 -1.6476330e+00 8.0210979e-13 -4.0290828e+00 -1.6493780e+00 8.0291527e-13 -4.0328056e+00 -1.6511199e+00 8.0371935e-13 -4.0365207e+00 -1.6528586e+00 8.0452202e-13 -4.0402283e+00 -1.6545943e+00 8.0532330e-13 -
-4.1163153e+00 -1.6903164e+00 8.2182182e-13 -4.1198535e+00 -1.6919825e+00 8.2259166e-13 -4.1233838e+00 -1.6936455e+00 8.2336006e-13 -4.1269064e+00 -1.6953052e+00 8.2412700e-13 -
End Ephemeris
Torque File (.tq) Format
The torques in this file are in body fixed coordinates and have units of
2
(Newton Meters) which is (Kg Meters / Sec). The format of a data line is:
(Seconds from given epoch) (X Torque) (Y Torque) (Z Torque)
A sample torque file is shown below.
Listing C-5. Sample Torque File Format
stk.v.3.0
BEGIN Torques
NumberOfTorques
20
ScenarioEpoch
1 Jan 1995 00:00:00.0
TorquesTimeBodyFixed
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0.000
2.000
4.000
6.000
8.000
10.000
12.000
14.000
16.000
18.000
20.000
22.000
24.000
26.000
28.000
30.000
32.000
34.000
36.000
38.000
END Torques
1.005
1.013
1.024
1.031
1.074
1.053
1.086
1.112
1.134
1.146
1.152
1.168
1.177
1.183
1.186
1.172
1.161
1.139
1.112
1.005
-0.003
-0.021
-0.043
-0.065
-0.064
-0.066
-0.053
-0.047
-0.044
-0.042
-0.039
-0.035
-0.033
-0.029
-0.025
-0.022
-0.019
-0.012
-0.008
-0.003
2.223
2.132
2.085
1.869
1.883
1.964
2.104
2.325
2.417
2.632
2.788
2.871
2.863
2.851
2.844
2.838
2.836
2.835
2.835
2.835
Color Bitmap/Pixmap (.bmp/.xpm) File
Format
You can import a color pixmap (.xpm for UNIX or .bmp for PC) file
to be used as a map background image or graphics marker for an
object. To create a pixmap, use a pixmap utility such as pixmap
(UNIX) or MS Paint (PC). The pixmap application can be found at
ftp.x.org; it currently resides in the R5contrib/ folder.
Listing C-6. Pixmap File Format
/* XPM */
static char *star[] = {
/* width height num_colors chars_per_pixel */
"
20
16
4
1",
/* colors */
". c #ffffff",
"# c #9b9b9b",
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"a c #12ff86",
"b c #000000",
/* pixels */
"####################",
"#########.b#########",
"###bbbbbbabbbbbbb###",
"###bb.bbbabbbbbbb###",
"###bbb.bb.bb.bbbb###",
"###bbbb.b.b.bbbbb###",
"###bbbbb...bbbbbb###",
"##.a.a.........aa.##",
"##bbbbbb...bbbbbbb##",
"###bbbb.b.b.bbbbb###",
"###bbbbbb.bb.bbbb###",
"###bbbbbb.bbbbbbb###",
"###bbbbbbabbbbbbb###",
"###bbbbbbabbbbbbb###",
"#########.b#########",
"####################"};
Database File Formats
You can use your own databases to import satellites, cities, facilities, and stars
into STK. The individual databases used by the Satellite, City, Facility and
Star Database tools are discussed in the sections following.
Satellite Database
The Satellite Database is comprised of a total of six files. You can create your
own Satellite Database by following the format expected/required by STK.
For example, the stkActiveTLE database [i.e., all satellites considered active
and having a two-line element (TLE) set available] includes the following
files:
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Table C-3. stkActiveTLE database files
File
Contents
stkActiveTLE.sd
Main database file
stkActiveTLE.fr
Frequency Information
stkActiveTLE.wr
Write Ups
stkActiveTLE.om
Owner/Mission
stkActiveTLE.tce
Two-line Element Sets
stkActiveTLE.gd
Latest update information
The first three files contain fixed-width fields. One row represents a single
entry.
stkActiveTLE.sd File
This is the main Satellite Database file; it contains all searchable fields. The
format, starting at column zero (0) is as follows:
Table C-4. stkActiveTLE.sd file description
Column
Width
Description
0-4
5
SSC number. Valid values are 00001 - 99999
(KEY FIELD) Leading zeros are expected by
STK.
5-19
15
Common name. This is any common name that
may be used. There may be multiple entries for a
satellite; these may differ in the common name.
20-34
15
Official name. This is the unique official name
for the entry
35-41
11
International number. Unique number assigned
to all objects achieving orbit and observed by
USSC.
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C-22
Column
Width
Description
46-55
10
Owner/country. Owner of satellite.
56-65
10
Mission. Category of mission.
66-68
3
Launch site. May be abbreviated.
69-76
8
Launch date. YYYYMMDD format.
77-80
4
Launch time, in military format (0-2400 hours).
81-100
20
Decay/deorbit date. Either the date (YYMMDD)
of deorbit, or the type of orbit. For example,
heliocentric orbit
101-104
4
Launch sequence number. Represents the
number of successful launches. These are
numbered sequentially from Sputnik 1 through
present. If more than one satellite was launched
on a single booster or shuttle, this number is
repeated.
105-112
8
Weight (mass). This is the 'weight' of the satellite
as it achieved orbit. Normally stored in Kg.
113-118
6
Apogee in Km.
119-123
5
Perigee in Km.
124-130
7
Period. Time in minutes for the satellite to
complete one revolution of the earth. This
number is rounded to nearest tenth of a minute.
131-135
5
Inclination. Angle (deg) between the plane of the
orbit and the equatorial plane of the planet.
136-140
5
Geostationary position. Location of the satellite
at the equator. (0.1° to 360°). All positions are
listed as East. In other words, if known as 0.0° to
179.9° East or West, 0.0° would become 360°.
141-148
8
Status. Active or Inactive
149-156
8
Date of last database update (YYYYMMDD)
Satellite Tool Kit® User’s Manual
Importing Files into STK
Column
Width
Description
157-159
3
These are record terminator
stkActiveTLE.fr File
This is the frequency file; it contains all downlink frequencies known for the
satellite. Frequencies are stored in Megahertz. Currently, STK uses this
information for description purposes only. There may be multiple entries for
a particular satellite; one column represents a single entry. The format,
starting at column zero (0) is as follows:
Table C-5. stkActiveTLE.fr file description
Column
Width
Description
0-4
5
SSC number. Valid values 00001 - 99999 (KEY
FIELD)
5-11
7
Low frequency. Low frequency in a range or an
individual frequency if known.
12-19
7
High frequency. High frequency in a range.
stkActiveTLE.wr File
This is the write up file. There can be multiple rows for a single satellite. The
format, starting at column zero (0) is as follows:
Table C-6. stkActiveTLE.wr file description
Column
Width
Description
0-4
5
SSC number. Valid values 00001 - 99999 (KEY
FIELD)
5-49
45
Write Up. Write up text.
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Importing Files into STK
stkActiveTLE.om File
This is the Owner/Mission file. It contains a list of all the valid owners and
missions in the database. This file is used to build the list of owners/mission
available in the user interface. If this file isn’t available, STK is unable to
search for satellite owners or mission. The file is in a basic STK data File
format.
Listing C-7. Example of owner/mission file for the satellite database
BEGIN Owner
Arabia
Argentina
AsiaSat
Australia
Brazil
CIS
Canada
China
ESA
FG
France
Germany
IMSO
ITSO
India
Indonesia
Israel
Italy
Japan
Korea
LU
Luxembourg
Malaysia
Mexico
NATO
Norway
Spain
Sweden
Thailand
Turkey
UK
USA
USSR
END Owner
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BEGIN Mission
COMM-CIVIL
COMM-JOINT
COMM-MIL
COMM-TEST
END Mission
stkActiveTLE.tce File
This file contains all TLE sets for the satellites in the database. Single entries
are supported in this file. The element sets represent the latest available TLE
data for each satellite.
Listing C-8. Example of stkActiveTLE.tce file for the satellite database
1
5U 58002B
0 0120
2
5 034.2513
10.8174658925824
1
11U 59001A
0 0203
2
11 032.8804
11.7409173258396
1
20U 59007A
0 0535
2
20 033.3429
11.4072245022537
1
22U 59009A
0 0014
2
22 050.3006
14.6177602893174
1
29U 60002B
0 0402
2
29 048.3958
14.6569320293349
1
45U 60007A
0 0516
2
45 066.6922
14.2817197887316
1
46U 60007B
0 0897
2
46 066.6913
14.3768009787795
1
58U 60013A
0 0205
2
58 028.3283
13.4601762576200
.
96205.98321854 -.00000027 +00000-0 -14099-4
066.1786 1857117 028.0627 340.8690
96206.36121278 +.00000133 +00000-0 +54518-4
202.5230 1520485 273.9362 068.9389
96205.92525397 +.00000273 +00000-0 +12273-3
027.2653 1734225 118.0074 260.6629
96206.45877471 -.00000102 +00000-0 +21719-4
204.3086 0233615 047.3113 314.7242
96206.44555374 -.00000100 +00000-0 +17005-4
249.9969 0027300 167.7961 192.3614
96206.26539704 -.00000031 +00000-0 +19837-4
269.7390 0272137 172.8883 187.6200
96206.07691753 -.00000013 +00000-0 +22917-4
068.8100 0237430 118.0002 244.5344
96206.11147628 +.00000075 +00000-0 -18707-4
091.6008 0165323 173.5795 186.6915
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Importing Files into STK
.
.
stkActiveTLE.gd File
This is the generic database file. It contains information concerning the last
update of the database. This file is used by the online update option to
determine which records to supply. This file is in a basic STK data file
format.
Listing C-9. Example of stkActiveTLE.gd file
BEGIN DatabaseUpdate
Version
LastUpdate
END DatabaseUpdate
1.0
19970405
TLE File Format
TLE files consist of a listing of two-line element sets as provided by
the U.S. Space Command (USSC). TLE sets are used by the Merged
Simplified General Perturbation (MSGP4) propagator within STK.
The following table describes the format of a TLE set.
Table C-7. Card 1
C-26
Column
Description
1
Card number
2
Blank
3-7
Satellite or SSC number
8
Security classification
9
Blank
10-17
International number
Satellite Tool Kit® User’s Manual
Importing Files into STK
Column
Description
18
Blank
19-20
Epoch Year
21-32
Epoch day to eight decimal places
33
Blank
34-43
N/2 - Revolutions per day squared
44
Blank
45-52
N/6 - Revolutions per day cubed
53
Blank
54-61
Bstar drag
62
Blank
63
Ephemeris
64
Blank
65-68
Element set number
Table C-8. Card 2
Column
Description
1
Card number
2
Blank
3-7
Satellite or SSC number
8
Blank
9-16
Inclination (degrees)
17
Blank
18-25
Right ascension of node (degrees)
26
Blank
27-33
Eccentricity (decimal point understood)
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C-27
Importing Files into STK
Column
Description
34
Blank
35-42
Argument of perigee (degrees)
43
Blank
44-51
Mean anomaly (degrees)
52
Blank
53-63
Mean motion (revolutions per day)
64
Revolution number at epoch
A sample TLE file is shown below for your reference.
Listing C-10. TLE File Format
1 6909U 73081A
0 0102
2 6909 089.7704
13.6800259831943
1 6909U 73081A
0 0102
2 6909 089.7704
13.6800259831943
1 8746U 76023A
0 0049
2 8746 015.3575
01.0026721801907
1 8747U 76023B
0 0012
2 8747 015.3521
01.0027314701907
1 9478U 76101A
0 0615
2 9478 012.9069
01.0028020801458
1 10637U 78012A
0 0244
2 10637 035.6846
01.0025756801920
1 12089U 80098A
0 0816
2 12089 006.2358
01.0026574302452
C-28
96095.97701855 +.00000078 +00000-0 +70284-4
093.8156 0162024 105.7374 256.1702
96095.97701855 +.00000078 +00000-0 +70284-4
093.8156 0162024 105.7374 256.1702
96096.15457780 -.00000097 +00000-0 +10000-3
273.2760 0013056 142.8352 087.7876
96096.15673441 -.00000102 +00000-0 +00000-0
273.3512 0023832 136.2812 095.6103
96093.28172880 +.00000049 +00000-0 +10000-3
033.7479 0005869 099.5006 341.4463
96095.86463512 -.00000154 +00000-0 +10000-3
084.2647 1353688 054.8200 331.5684
96093.11987032 -.00000271 +00000-0 +00000-0
056.4726 0003308 303.2412 193.6849
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Importing Files into STK
1 12994U 81119A
0 0530
2 12994 005.8775
01.0027132601693
1 13083U 82017A
0 0638
2 13083 005.8733
00.9922799103227
1 13367U 82072A
0 0894
2 13367 098.0838
14.5717754372990
1 13595U 82097A
0 0370
.
.
.
2 23741 000.0085
01.0027165000118
1 23748U 95071A
0 0242
2 23748 065.0214
15.5209027201663
1 23751U 95072A
0 0086
2 23751 098.6992
14.2163508701405
1 23752U 95072B
0 0041
2 23752 098.5532
14.2488888901408
1 23754U 95073A
0 0064
2 23754 000.0342
01.0027393100088
1 23757U 95074A
0 0063
2 23757 022.9772
14.9762623401449
96091.51457987 -.00000150 +00000-0 +10000-3
057.5493 0005167 316.4773 157.4150
96088.99006407 +.00000070 +00000-0 +10000-3
057.2095 0030143 271.4999 088.2606
96096.17389770 +.00000033 +00000-0 +17128-4
149.2719 0007846 015.4314 344.7113
96094.59762657 -.00000001 +00000-0 +10000-3
167.3677 0002445 201.5504 192.8057
96096.18479622 +.00001785 +00000-0 +34075-4
133.8895 0010447 300.9161 059.0956
96096.13625365 -.00000044 +00000-0 +00000-0
171.3332 0001121 059.0289 301.1001
96096.13206129 -.00000020 +00000-0 +10000-4
170.2575 0004324 212.4478 147.6434
96095.49851374 -.00000008 +00000-0 +00000-0
124.0248 0002246 262.3037 227.1814
96096.09776230 +.00000555 +00000-0 +17404-4
189.2860 0013321 265.4654 094.4354
City Database
The City Database is comprised of a total of three files. You can create your
own City Database by following the format expected/required by STK. For
example, the stkCityDb database (the database shipped with STK) includes
the following files:
Satellite Tool Kit® User’s Manual
C-29
Importing Files into STK
Table C-9. City database files
File
Contents
stkCityDb.cd
Main database file
stkCityDb.cc
Counties
stkCityDb.gd
Latest update information
The first file contains fixed-width fields, where one row represents a single
entry. The remaining are in the standard STK database file format. File
formats for the city database are described in the subsections following.
stkCityDb.cd File
This is the main City Database file; it contains all searchable fields. The
format, starting at column zero (0) is as follows:
Table C-10. stkCityDb.cd file description
C-30
Column
Width
Description
0-6
7
City Key. Unique integer identifier
7-36
30
City Name
37-38
2
City Type:
♦
0 - Populated Place
♦
1 - Administration Center
♦
2 - National Capital
♦
3 - Territorial Capital
39-58
20
Country
59-98
40
Province/State
99-101
3
Province rank
102-112
11
Population
Satellite Tool Kit® User’s Manual
Importing Files into STK
Column
Width
Description
113-115
3
Population Rank
116-132
17
Latitude (deg)
133-149
17
Longitude (deg)
150-152
3
These are record terminators.
stkCityDb.cc File
This is the country and city type file. It contains a list of all the valid
countries and city types. This file is used to build the list of country and city
types available in the user interface. If this file isn’t available, STK is unable to
search for countries or city types. The file is in a basic STK data File format.
Listing C-11. Example of country and city type file
Begin Country
Albania
Antigua and Barbuda
Argentina
Armenia
Aruba
Australia
Austria
Croatia
Cuba
Czech Republic
.
.
.
Mauritania
United States
Uruguay
Uzbekistan
Vanuatu
Venezuela
Virgin Islands
Western Samoa
End Country
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C-31
Importing Files into STK
Begin Type
Populated Place
Administration Center
National Capital
Territorial Capital
End Type
stkCityDb.gd File
This is the generic database file. It contains information concerning the last
update of the database. This file is used by the online update option to
determine which records to supply. The file is in a basic STK data file format.
Listing C-12. Example of stkCityDb.gd file
BEGIN DatabaseUpdate
Version
LastUpdate
END DatabaseUpdate
1.0
19970405
Facility Database
The Facility Database is comprised of a total of three files. You can create
your own Facility Database by following the format expected/required by
STK. For example, the stkFacility database (the database shipped with STK)
includes the following files:
Table C-11. stkFacility database files
File
Contents
stkFacility.fd
Main database file
stkFacility.fn
Facility Networks
stkFacility.gd
Latest update information
The first file contains fixed-width fields, where one row represents a single
entry. The remaining are in the standard STK database file format. File
formats for the facility database are described in the subsections following.
C-32
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Importing Files into STK
stkFacility.fd File
This is the main Facility Database file; it contains all searchable fields. The
format, starting at column zero (0) is as follows:
Table C-12. stkFacility.fd file description
Column
Width
Description
0-36
37
Site Name
37-48
12
Network ex. USAF
49-58
10
Latitude (deg)
59-69
11
East Longitude (deg)
70-76
7
Altitude (m)
77-79
3
These are record terminators
stkFacility.cc File
This is the network file. It contains a list of all the valid facility network
types. This file is used to build the list of facility networks available in the
user interface. If this file isn’t available, STK is unable to search for facility
networks. The file is in a basic STK data File format.
Listing C-13. Example of stkFacility.gd file
BEGIN Network
CNES
CRL
DLR
ESA
INPE
ISRO
Launch
NASA DSN
NASDA
NOAA NESDIS
Optical
Satellite Tool Kit® User’s Manual
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Importing Files into STK
Other
SCF
SSC
USAF
END Network
stkFacility.gd File
This is the generic database file. It contains information concerning the last
update of the database. This file is used by the online update option to
determine which records to supply. This file is in a basic STK data file
format.
Listing C-14. Example of stkFacility.gd file
BEGIN DatabaseUpdate
Version
LastUpdate
END DatabaseUpdate
1.0
19970405
Star Database
The Star Database is comprised of a total of four files. You can create your
own Star Database by following the format expected/required by STK. For
example, the stkStarDb database (the database shipped with STK) includes
the following files:
Table C-13. stkStarDb database files
C-34
File
Contents
stkStarDb.bd
Main database file
stkStarDb.bn
Common Names
stkStarDb.bc
Constellation Names
stkStarDb.gd
Latest update information
Satellite Tool Kit® User’s Manual
Importing Files into STK
The first two files contains fixed width fields where one row represents a
single entry. The remaining files are in the standard STK database file format.
File formats for the star database are described in the subsections following.
stkStarDb.bd File
This is the main Star Database file. The format, starting at column zero (0) is
as follows:
Table C-14. stkStarDb.cd file description
Column
Width
Description
0-3
4
Harvard Revised Number
4-24
20
Currently not used by STK
25-30
6
Henry Draper Number
31-36
6
SAO Catalog Number
37-40
4
5 Fundamental Catalog Number
41-74
32
Currently not used by STK
75-84
10
Right Ascension (J2000) (hhmmss.sss)
85-94
10
Declination (J2000) (ddmmss.ss)
95-107
11
Currently not used by STK
108-112
5
Visual magnitude (UBV system)
113-161
47
Currently not used by STK
162-168
7
Proper Motion Right Ascension (J2000)
169-174
6
Proper Motion Declination (J2000)
175
1
Currently not used by STK
176-180
5
Parallax
181-230
48
Currently not used by STK
Satellite Tool Kit® User’s Manual
th
C-35
Importing Files into STK
Column
Width
Description
231-250
20
Constellation Name
251-253
3
These are record terminators
stkStarDb.bn File
This is the common name file. There can be multiple rows for a single star.
The format, starting at column zero (0) is as follows:
Table C-15. stkStarDb.bn file description
Column
Width
Description
0-3
4
Harvard Revised Number
4-16
11
Currently not used by STK
17-36
20
Common Name
37-39
3
These are record terminators
stkStarDb.bc File
This is the constellation file. It contains a list of all the valid star
constellations. This file is used to build the list of constellations available in
the user interface. If this file isn’t available, STK is unable to search for
constellations of stars. The file is in a basic STK Data File format.
Listing C-15. Example of stkStarDb.bc file
BEGIN Constellation
Andromeda
Antlia
Apus
Aquarius
Aquila
Ara
Aries
C-36
Satellite Tool Kit® User’s Manual
Importing Files into STK
Auriga
Bootes
Caelum
Camelopardus
Cancer
Canes Venatici
Canis Major
Canis Minor
Capricorn
.
.
.
Taurus
Telescopium
Triangulum
Triangulum Australe
Tucana
Ursa Major
Ursa Minor
Vela
Virgo
Volans
Vulpecula
END Constellation
stkStarDb.gd File
This is the generic database file. It contains information concerning the last
update of the database. This file is used by the online update option to
determine which records to supply. This file is in a basic STK data file
format.
Listing C-16. Example of stkStarDb.gd file
BEGIN DatabaseUpdate
Version
LastUpdate
END DatabaseUpdate
Satellite Tool Kit® User’s Manual
1.0
19970405
C-37
Importing Files into STK
Solar Flux Files
The solar flux file, used with the Lifetime tool, contains predicted values of the
monthly mean 10.7 cm solar radiation flux (F10.7) and geomagnetic index (Ap).
The first line of the file consists of seven numbers:
♦
Year the data begins;
♦
Month the data begins;
♦
Year the data ends;
♦
Month the data ends;
♦
Year the predictions were generated;
♦
Month the predictions were generated; and
♦
Number of data points (lines) that follow.
All dates are UTC.
1RWH
Each of the remaining lines contains the year and month (day is assumed to
be the 15th), followed by the +2σ and nominal predictions of the 10.7 cm
solar flux F10.7 and the +2σ and nominal predictions of the geomagnetic index,
Ap, respectively.
The file may contain any number of data points, but the Lifetime tool only
uses the first 250 (this corresponds to 20 years, 10 months worth of data). If
the Lifetime calculations continue past the last data point in the solar flux file,
the 11-year solar cycle is assumed to repeat as many times as necessary.
Listing C-17. Sample solar flux data file
1997
1997
1997
C-38
1
1
2
1998
98.1
98.8
1
79.9
78.3
1985
18.5
17.8
6
12.6
12.6
13
Satellite Tool Kit® User’s Manual
Importing Files into STK
1997
1997
1997
1997
1997
1997
1997
1997
1997
1997
1998
3
4
5
6
7
8
9
10
11
12
1
100.0
100.4
98.3
95.2
92.3
91.0
91.4
91.6
91.2
90.8
90.2
Satellite Tool Kit® User’s Manual
77.4
76.9
76.6
76.3
76.0
75.6
75.1
73.8
73.2
72.6
72.9
16.9
16.4
16.6
16.8
17.0
17.3
17.6
17.5
17.3
16.8
16.0
12.6
12.5
12.6
12.7
12.5
12.4
12.1
12.0
11.7
11.6
11.5
C-39
Importing Files into STK
127(6
C-40
Satellite Tool Kit® User’s Manual
Appendix D
HPOP TECHNICAL
NOTES
Technical Notes
Unpredictable Earth motions can’t be modeled at the present time. They
include polar motion, irregular variations in the Earth’s rotation rate and
continental drift. Polar motion causes the poles to wander in irregular circles
in a region approximately 30 m square, taking about a year to complete each
circle. Irregular variations in the Earth’s rotation rate can change the length
of the day by up to 0.25 milliseconds (ms) per year; however, such large
changes tend to cancel out over time, leaving a residual secular increase of 1.5
ms per century. Continental drift occurs at rates of up to 5 centimeters (cm)
per year.
Chapter Contents
Technical Notes........................................................................................... D-1
HPOP Values............................................................................................... D-2
Satellite Tool Kit® User’s Manual
D-1
HPOP Technical Notes
HPOP Values
The HPOP uses the following values for various physical constants:
Table D-1. Physical constants
Symbol
Constant
Value
Measured
In
µE
Gravitational Constant of Earth
398600.44
km /sec
µS
Gravitational Constant of Sun
1.32712438e11
km /sec
µM
Gravitational Constant of Moon
4902.794
km /sec
RE
Equatorial Radius of Earth
6378.138
km
fE
Flattening Coefficient of Earth
0.00335281
c
Speed of Light
299792.458
km/sec
LS
Luminosity of Sun
3.823e26
W
3
2
3
2
3
2
The HPOP uses the following values for the differences among
various astronomical time systems:
Table D-2. Astronomical time systems
Time System
Difference
Unit
TAI-UTC
Tabulated based on leap seconds
seconds
UTC-UT1
0.216
seconds
TAI-TDT
-32.184
seconds
The models for atmospheric drag and solar radiation pressure use the
following default values for the coefficients of drag and solar radiation
pressure:
D-2
Satellite Tool Kit® User’s Manual
HPOP Technical Notes
Table D-3. Coefficients of drag and solar radiation pressure
Coefficient
Value
cD (coeff of drag)
2.0
cR (coeff of solar radiation pressure)
2.0
These coefficients are defined by the following expressions for the
accelerations due to drag and solar radiation pressure.
Acceleration caused by drag is:
Acceleration caused by solar radiation is:
2
 A   ρV 
a D ≡ ( c D )  

 M  2 
 A  L 
a R ≡ ( c R )   S 2 
 M   8πcr 
where:
cR =
coefficient for solar radiation
cD =
coefficient for drag
A = satellite cross-sectional area
M = satellite mass
ρ
= atmosphere density
V = satellite speed relative to the atmosphere
LS = luminosity of the sun
c
= speed of light
r
= distance of satellite from sun
The modified Harris-Priester atmosphere density model uses the following
default values for the specified parameters:
Satellite Tool Kit® User’s Manual
D-3
HPOP Technical Notes
Table D-4. Harris-Priester parameters
Symbol
Parameter
Value
F10.7
Solar Radio Flux
150
ψB
Diurnal Bulge Lag Angle
30°
eB
Diurnal Bulge Exponent
6
The user can specify any fixed value of F10.7 between 65 (solar minimum)
and 275 (slightly higher than the highest recorded solar maximum).
D-4
Satellite Tool Kit® User’s Manual
Appendix E
HIGHRESOLUTION
MAPS TECHNICAL
NOTES
Overview
The High Resolution Maps module is based on the Relational World
Databank 2 (RWDB2). RWDB2 is available to the public in ASCII format
from the Earth Science Information Office of the U.S. Geological Survey.
The RWDB2 database was designed for producing small-scale maps, not for
applications requiring high geodetic accuracy, such as navigation.
Chapter Contents
Definitions ....................................................................................................E-2
Satellite Tool Kit® User’s Manual
E-1
High-Resolution Maps Technical Notes
RWDB2 Features..........................................................................................E-3
Coastlines................................................................................................E-3
Islands.....................................................................................................E-4
Lakes .......................................................................................................E-4
Rivers.......................................................................................................E-5
International Boundaries.........................................................................E-6
Provincial Boundaries..............................................................................E-8
Definitions
The terms briefly defined here are taken from the RWDB2 Reference
Manual.
E-2
Term
Description
Rank
A hierarchical order of importance within
features or a way to distinguish subfeatures.
Rank 1 rivers are the most important, while
rank 5 rivers are minor. A rank 1
international boundary is delimited, while a
rank 2 is not less important but is simply
indefinite or in dispute. This allows one to
symbolize the lines differently or to vary the
complexity and density of the map. Note
that the ranks of most features are related to
WDB2, the names data bank, and other
databases. Ranks that appear to be missing
may be those that have been eliminated,
moved to other features on ranks, or those
planned for the future.
Satellite Tool Kit® User’s Manual
High-Resolution Maps Technical Notes
Term
Description
Geodetic vs.
Geocentric
RWDB2 should be considered to be
geocentric because the data is mixed, and,
considering the small input scale, one
probably could not tell the difference.
Accuracy
Although the potential data storage
accuracy for RWDB2 is 10 centimeters, one
should consider the data as being accurate to
the nearest second at best.
RWDB2 Features
The following subsections describe the features of the RWDB2 that have
been included in the Hi-Resolution Maps module.
Coastlines
Rank
Description
1
Coastline
21
Major ice shelves
22
Minor ice shelves
Comments
◊
Coastlines include the coasts of Africa, Asia, Australia,
Europe, Greenland, North America, South America, the
Black Sea, and the Caspian Sea.
Satellite Tool Kit® User’s Manual
E-3
High-Resolution Maps Technical Notes
Ice shelves are found only in Antarctica.
◊
Islands
Rank
Description
1
Major islands that should appear on all maps
2
Additional major islands
3
Moderately important islands
4
Additional islands
5
Minor islands
6
Very small minor islands
8
Reefs
9
Shoals
Comments
◊
Rank 1 islands should be called out on all maps
◊
Ranks 5 and 6 are normally found in double-line rivers, in
lakes, and between larger islands.
Lakes
E-4
Rank
Description
1
Lakes that should appear on all maps
2
Major lakes
Satellite Tool Kit® User’s Manual
High-Resolution Maps Technical Notes
Rank
Description
3
Additional major lakes
4
Intermediate lakes
5
Minor lakes
6
Additional minor lakes
7
Swamps
11
Intermittent major lakes
12
Intermittent minor lakes
14
Major salt pans
15
Minor salt pans
23
Glaciers
Comments
◊
Glaciers are currently found only in Iceland.
◊
Many small lakes have the same rank as the rivers that run
through them; a very small lake may be a rank 2 because a
rank 2 river runs through it. Displaying rivers of a certain
rank without displaying lakes of the same rank may result
in gaps in the rivers (see Rivers, comment 1).
◊
A reservoir may be shown as a double-lined river (see
Rivers, comment 3).
Rivers
Rank
Description
1
Double-line rivers
Satellite Tool Kit® User’s Manual
E-5
High-Resolution Maps Technical Notes
Rank
Description
2
Major rivers
3
Additional major rivers
4
Intermediate rivers
5
Minor rivers
6
Additional minor rivers
10
Major intermittent rivers
11
Additional intermittent rivers
12
Minor intermittent rivers
21
Major canals
22
Minor canals
23
Irrigation canals
Comments
◊
When displaying rivers of a given rank, it may be necessary
to display lakes of the same rank to prevent gaps in some
rivers (see Lakes, comment 3).
◊
Ranks 1 and 2 form the major river systems.
◊
Reservoirs may appear as double-line (Rank 1) rivers (see
Lakes, comment 4).
International Boundaries
E-6
Rank
Description
1
Demarcated or delimited
Satellite Tool Kit® User’s Manual
High-Resolution Maps Technical Notes
Rank
Description
2
Indefinite or in dispute
3
Lines of separation or sovereignty on land
4
Lines of separation or sovereignty in the sea
5
Other lines of separation or sovereignty in the sea.
Represents one generalization when island jurisdiction
must be shown
6
Continental shelf boundary in Persian Gulf
7
Demilitarized zone lines in Israel
8
No defined line: tone guide for lines in Arabian
peninsula, Chad-Libya, and India-Pakistan
9
Selected claimed lines
50
Old Panama Canal Zone lines
51
Old N. Yemen-S. Yemen
52
Old Jordan-Iraq
53
Old Iraq-Saudi Arabia Neutral Zone lines
54
Old East Germany, West Germany, and Berlin lines
55
Old North-South Vietnam boundary
56
Old Vietnam DMZ lines
57
Old Kuwait-Saudi Neutral Zone lines
58
Old Oman-Yemen line of separation
Comments
◊
Status and/or rank is defined by the U.S. State Department.
Other lines in dispute, indefinite, or lines of separation may
exist but were not input due to scale.
Satellite Tool Kit® User’s Manual
E-7
High-Resolution Maps Technical Notes
◊
Rank 2 boundaries are found between El Salvador and
Honduras, Colombia and Ecuador, Ecuador and Peru,
Venezuela and Guyana, Guyana and Suriname, Brazil and
French Guyana, French Guyana and Suriname, India and
China, India and Bangladesh, China and Russia, Botswana
and Namibia, Zaire and Zambia, Qatar and UAE, UAE and
Saudi Arabia, Congo and Zaire, and Iraq and Jordan.
◊
Rank 3 boundaries are found between Cuba and USA,
Somalia and Ethiopia, Egypt and Sudan, Kenya and Sudan,
Oman and UAE, India and Pakistan, India and China, and
N. Korea and S. Korea.
◊
Rank 4 boundaries are found between Malaysia and the
Philippines and Russia and Alaska.
◊
Rank 5 boundaries are found between Greece and Turkey,
Trinidad and Venezuela, Japan and Russia, Malaysia and
Indonesia, Pacific island groups, and Russia and China.
Provincial Boundaries
E-8
Rank
Description
1
First order
2
Second order
3
Third order
4
Special boundaries
54
Pre-unification German administration lines
61
First order boundaries in the water
62
Second order boundaries in the water
63
Third order boundaries in the water
99
Disputed lines or “lines under discussion”
Satellite Tool Kit® User’s Manual
High-Resolution Maps Technical Notes
Comments
◊
Provincial boundaries are provided for the United States
and Canada only.
Satellite Tool Kit® User’s Manual
E-9
High-Resolution Maps Technical Notes
127(6
E-10
Satellite Tool Kit® User’s Manual
STK USER’S MANUAL
INDEX
2
2D Map------------------------------------------------------2-11
Attributes----------------------------------------------2-12
Output Device -----------------------------------2-12
Page Layout----------------------------------------2-12
Prinert Command -----------------------------2-12
Adding an Object --------------------------------------2-6
Advanced Analysis
Astrodynamics------------------------------------1-10
Attitude Simulation----------------------------1-10
Data Management---------------------------1-11
Data Visualization------------------------------1-11
Sensor Constraints-----------------------------1-10
Sensor Definition-------------------------------1-10
A
Advanced Analysis -------------------------------------1-9
Attitude Targeting -----------------------------1-10
About STK --------------------------------------------------17-9
Accelerator Keys---------------------------------------2-21
Access ------------------------------------------- 13-3, 18-11
AER Data----------------------------------------------13-7
Advanced Constraints
Aircraft----------------------------------------6-54, 7-10
Customizing a Report-----------------------13-8
Graphics-----------------------------------------------13-5
Removing--------------------------------------------13-9
Reports -------------------------------------------------13-6
Targeted Sensors---------------------------- 13-10
Access Constraint
Close Approach Tool--------------------- 13-31
Access Graphics------------------------------------ 13-34
Accesses
Removing----------------------------------------- 13-29
Acknowledge----------------------------------------------4-4
Satellite Tool Kit® User’s Manual
Ground Vehicles --------------------6-54, 7-10
Launch Vehicles ---------------------6-54, 7-10
Missiles---------------------------------------6-54, 7-10
Satellites-------------------------------------6-54, 7-10
Sensors ---------------------------------------------- 12-24
Ships-------------------------------------------6-54, 7-10
Advanced Options
Close Approach Tool--------------------- 13-32
Advanced Settings
LOP--------------------------------------------------------6-20
Advanced TLE ------------------------------------------6-26
AER Data
I-1
Index
Access ---------------------------------------------------13-7
AER Report --------------------------------------------- 13-13
Lighting--------------------------------------------- 13-13
Aircraft
Access ---------------------------------------------------13-3
Basic Properties
Attitude -----------------------------------------------7-4
Route---------------------------------------------------7-2
Constraints
Advanced-----------------------------6-54, 7-10
Basic--------------------------------------------------6-47
Sun----------------------------------------------------6-50
Temporal-----------------------------------------6-52
Description------------------------------------------2-17
Graphics Properties
Attributes --------------------------------------------7-6
Display Times ------------------------------------7-8
Great Arc Propagator--------------------------7-2
Properties of-------------------------------------------7-1
Step Size --------------------------------------------------7-2
Swath------------------------------------------------- 13-23
Alignment at Epoch -------------------------------6-13
All Of -----------------------------------------------------------18-7
Allow Async--------------------------------------------------4-4
Allow Connect --------------------------------------------4-4
Allow Online Operations-------------------------4-5
Altitude Range---------------------------------------------9-9
Angle Unit ----------------------------------------------------5-9
Angle-Off-Boresight, Custom Sensor----B-9
Angular Rate----------------------------------6-48, 9-12
Animating a Scenario-----------------------------3-18
Animation-----------------------------------------------------5-4
Animation & Vehicle Tracks------------------3-18
Animation Time Steps -------------------------------3-4
Antennas
Parabolic ----------------------------------------------12-4
I-2
Any Of --------------------------------------------------------18-7
Apogee --------------------------------------------------- 14-10
Apogee Altitude------------------------------------------6-5
Apogee Radius--------------------------------------------6-5
Application
Exiting the Application -------------------------2-3
IPC Preferences -------------------------------------4-3
Online Operations-------------------------------4-5
Properties of-------------------------------------------4-1
Save Prefs------------------------------------------------4-2
Applications, External-----------------------------2-15
2-16
Archive Date ------------------------------------------ 14-13
Area Exposed to Sun--------------------------- 13-16
Area Targets
Access ---------------------------------------------------13-3
Attributes----------------------------------------------10-6
Basic Constraints--------------------------------10-7
Basic Properties
Boundary----------------------------------------10-2
Centroid ------------------------------------------10-3
Constraints-------------------------------------------10-7
Basic--------------------------------------------------10-7
Temporal-----------------------------------------10-9
Description------------------------------------------2-17
Graphics Properties
Attributes -----------------------------------------10-6
Temporal Constraints-----------------------10-9
Area to Mass Ratio------------------------6-16, 6-19
Argument of Latitude--------------------------------6-7
Argument of Perigee--------------------- 6-6, 6-23
Assigned Targets------------------------ 6-37, 12-13
At Least N---------------------------------------------------18-7
Atmospheric Drag--------------------------1-12, D-2
Attitude---------------------------------------------- 6-28, 7-4
Attitude Type --------------------------------------6-29
Satellite Tool Kit® User’s Manual
Index
Integrated Attitude----------------------------6-35
Launch Vehicles------------------------------------8-6
Missiles-----------------------------------------------------8-6
Orientation Type -------------------------------6-34
Target Pointing ----------------------------------6-36
Background----------------------------------------------6-56
Background,Map------------------------------------3-14
Ballistic Propagator-------------------------------------8-3
Barycentric Displacement ---------------------1-12
Basic Constraints
Aircraft---------------------------------------------------6-47
Attitude File Format --------------------------C-3, C-7
Keywords----------------------------------------------- C-3
Area Targets----------------------------------------10-7
Attitude File, External------------------------7-6, 8-7
Attitude Simulation----------------------------------1-10
Attitude Targeting -----------------------------------1-10
Attitude Type --------------------------------------------6-29
Attributes-------------------------------- 6-41, 7-6, 10-6
Facilities----------------------------------------------------9-6
Ground Vehicles -------------------------------6-47
Facilities ------------------------------------------------9-10
Launch Vehicles --------------------------------6-47
Missiles--------------------------------------------------6-47
Satellites------------------------------------------------6-47
Ships------------------------------------------------------6-47
Graphs------------------------------------ 15-13, 16-9
Targets--------------------------------------------------9-10
Launch Vehicles------------------------------------8-7
Basic Fifth Fundamental Catalog----- 14-16
Basic Properties ----------------------------------------2-16
Sensors -------------------------------------------------12-2
Map----------------------------------------------------------3-5
Missiles-----------------------------------------------------8-7
Planets --------------------------------------------------11-4
Stars-------------------------------------------------------11-4
Targets-----------------------------------------------------9-6
Auto Propagate -----------------------14-12, 14-20
Auto Save------------------------------------------------------4-2
Auxiliary Database-----------------------------------5-12
Average F10.7 -----------------------------------------6-16
Axis Annotations----------------------------------- 15-18
Az-El File Format ---------------------------------------- C-8
Az-El Mask--------------------------------------------------9-13
Facilities-------------------------------------------9-6, 9-8
Targets--------------------------------------------9-6, 9-8
Az-El Mask, Custom Sensor----------------------B-7
Azimuth Angle ------------------------------6-48, 9-11
Azimuth Rate --------------------------------------------9-12
Azimuthal Equidistant Projection--------3-11
B
B1950---------------------------------------------------------6-13
Satellite Tool Kit® User’s Manual
Basic Properties of a Constellation------18-6
Bitmap File Format----------------------------------C-19
Black Bodies----------------------------------------------1-12
Blink on Select------------------------------------------5-16
Boresight
Fixed--------------------------------------------------- 12-14
Tracking--------------------------------------------- 12-14
Boundaries
Area Targets----------------------------------------10-2
Browser Window------------------------------2-3, 2-4
Bstar-------------------------------------------------------------6-23
C
2-16
Cartesian Coordinate Type----------------------6-8
Cartesian Position--------------------------- 9-4, 10-5
CAT-----------------------See Close Approach Tool
Centroid-----------------------------------------------------10-3
Cartesian----------------------------------------------10-5
I-3
Index
Cylindrical --------------------------------------------10-5
Access Conditions -----------------------------18-8
Geocentric-------------------------------------------10-5
Basic Properties ----------------------------------18-6
Geodetic ----------------------------------------------10-4
Creating a Constellation------------------18-5
Spherical-----------------------------------------------10-4
Criteria---------------------------------------------------18-7
Chain ----------------------------------------------------------18-2
Basic Properties ----------------------------------18-3
All Of-------------------------------------------------18-7
Ordering Chain Objects------------------18-4
At Least N----------------------------------------18-7
Reports -------------------------------------------------18-8
Exactly N------------------------------------------18-8
Complete Chain Access ----------- 18-11
Constellation Name----------------------------- 14-16
Constellation, Walker -------------------------- 13-26
Constraints
Advanced ---------------------------------6-54, 7-10
Individual Object Access---------- 18-10
Individual Strand Access--------------18-8
Change Current Item-----------------------------3-17
Change Current Point ----------------10-3, 12-8
Charts, Strip-------------------------- See Strip Charts
Circular Orbit---------------------------------------------6-15
City Database---------------------------------14-1, 14-2
Querying the Database-------------------14-3
Search Results-------------------------------------14-4
City Database File Format---------------------C-29
Country/City Type File ---------------------C-31
City Database Files ----------------------------------C-30
City Name--------------------------------------------------14-4
City Type ----------------------------------------------------14-4
City Type File Format------------------------------C-31
Classical Coordinate Type ------------------------6-5
Clock Angles ---------------------------------------------12-3
Close Approach Tool--------------------------- 13-29
Computing--------------------------------------- 13-34
Closing a Scenario--------------------------------------2-5
Coefficient of Drag-----------------------6-16, 6-19
Collision--------------------------------------------------- 13-29
Common Name----------------------14-10, 14-16
Complete Chain Access Report-------- 18-11
Computing Close Approaches--------- 13-34
Conic Sensors-------------------------------------------12-3
Connection Method ---------------------------------4-4
Constellation-----------------------18-2, 18-4, 18-5
I-4
Any Of----------------------------------------------18-7
Area Targets----------------------------------------10-7
Basic ------------------------------------------------------6-47
Satellite--------------------------------------------------6-47
Sensors ---------------------------------------------- 12-21
Sun --------------------------------------------------------6-50
Content--------------- 15-7, 15-15, 16-6, 16-11
Continental Drift----------------------------------------D-1
Contour Graphics
Level Adding----------------------------6-46, 8-11
LevelAttributes -------------------------6-47, 8-12
Contour Levels------------------------------6-46, 8-11
Contours----------------------------------------------------6-45
Launch Vehicles --------------------------------8-10
Missiles--------------------------------------------------8-10
Coordinate Epoch -------------------------------------6-4
Coordinate Systems--------------------------------6-12
Alignment at Epoch -------------------------6-13
B1950---------------------------------------------------6-13
Fixed-------------------------------------------6-12, 6-29
Fmean Equinox---------------------------------6-13
Inertial---------------------------------------------------6-29
J2000----------------------------------------------------6-12
Mean of Date-------------------------------------6-13
Satellite Tool Kit® User’s Manual
Index
Mean of Epoch----------------------------------6-13
True of Date----------------------------------------6-13
True of Epoch ------------------------------------6-13
Coordinate Types---------------------------------------6-4
Cartesian -------------------------------------------------6-8
Classical----------------------------------------------------6-5
Delaunay Variables------------------------------6-9
Equinoctial----------------------------------------------6-8
Mixed Spherical----------------------------------6-10
Spherical-----------------------------------------------6-11
Copy Function -----------------------------------------2-15
Country ------------------------------------------------------14-4
Country File Format--------------------------------C-31
Creating a Chain -------------------------------------18-3
Creating a New Object----------------------------2-6
Cursor Position
Latitude and Longitude-------------------3-17
Custom Sensor
Angle-Off-Boresight -----------------------------B-9
Az-El Mask-----------------------------------------------B-7
Reference Plane------------------------------------B-2
Custom Sensor Patterns --------------- 12-6, B-1
Customizing a Report
Access ---------------------------------------------------13-8
Cut Function---------------------------------------------2-15
Cylindrical Position ------------------------- 9-5, 10-5
D
Database Defaults-----------------------------------5-12
Database File Formats ---------------------------C-20
Database Tab -------------------------------------------5-11
Database Type -----------------------------------------5-12
Date Format ------------------------------------------------5-9
Declination-----------------------6-12, 11-2, 14-16
Declination Angle -----------------------------------6-34
Deconflict -----6-38, 6-45, 7-9, 8-10, 9-10,
12-16, 12-21
Default Connection Settings-------------------4-4
Definition
Planets --------------------------------------------------11-3
Sensors -------------------------------------------------12-2
Stars-------------------------------------------------------11-2
Delaunay Variables Coordinate Type---6-9
Delete Point -------------------------------------------------7-4
Density Weighting Factor---------------------6-22
Description Tab----------------------------------------2-17
Aircraft---------------------------------------------------2-17
Area Targets----------------------------------------2-17
City Database -------------------------------------14-5
Facilities ------------------------------------------------2-17
Facility Database--------------------------------14-8
Facility TLE ---------------------------------------- 14-22
Ground Vehicles -------------------------------2-17
Launch Vehicles --------------------------------2-17
Missiles--------------------------------------------------2-17
Satellite Database --------------------------- 14-14
Satellite TLE--------------------------------------- 14-22
Data Management---------------------------------1-11
Data Visualization------------------------------------1-11
Database
City----------------------------------------------14-1, 14-2
Satellites------------------------------------------------2-17
Facility ----------------------------------------14-1, 14-5
Targets--------------------------------------------------2-17
Satellite---------------------------------------14-1, 14-8
Details
Map----------------------------------------------------------3-6
Star------------------------------------------- 14-1, 14-14
Satellite Tool Kit® User’s Manual
Ships------------------------------------------------------2-17
Star Database ---------------------------------- 14-17
Direction ----------------------------------------------------6-39
I-5
Index
Display Altitude ----------------------------------------5-17
Display Times----------------------6-44, 7-8, 12-20
Facilities----------------------------------------------------9-9
Launch Vehicles------------------------------------8-9
Missiles-----------------------------------------------------8-9
Targets-----------------------------------------------------9-9
Display, Dynamic -----See Dynamic Display
Distance Unit-----------------------------------------------5-8
Diurnal Rotation---------------------------------------1-12
DODS Elements---------------------------------------6-10
Drag-------------------------------------------------6-16, 6-19
Drag Area----------------------------------------------- 13-16
Drag Coeffient--------------------------------------- 13-16
Drag Cross-Sectional Area---------------------6-20
2-20
Duration-------------------------------6-53, 9-17, 10-9
Dynamic Display--------------------------------------16-1
Content------------------------------------------------16-6
Properties---------------------------------------------16-5
Title --------------------------------------------------------16-7
E
Earth Gravity----------------------------------6-16, 6-19
Eccentric Anomaly -------------------------------------6-7
Eccentricity --------------------------------------- 6-5, 6-23
ECF Velocity Alignment
Radial Constraint---------------6-32, 7-6, 8-7
Echo---------------------------------------------------------------4-4
ECI Velocity Alignment
Nadir Constraint ---------------6-32, 7-5, 8-6
ECITimePosVel File Format-------------------C-15
Edit Menu
Copy------------------------------------------------------2-15
Cut---------------------------------------------------------2-15
Paste------------------------------------------------------2-15
Element Set Number-------------------6-24, 6-27
Elevation Angle------------------6-48, 9-12, 10-8
I-6
Elevation Rate-------------------------------------------9-12
Ellipse, Osculating-----------------------------------6-14
Elliptical Orbit--------------------------------------------6-15
Elset Number--------------------------------------------5-15
Ephemeris File Format----------------------------- C-9
Keywords---------------------------------------------C-10
Ephemeris Time (ET) ------------------------------1-12
Epoch ------------------------------------------------ 5-2, 6-27
Coordinate---------------------------------------------6-4
Orbit--------------------------------------------- 6-4, 6-23
Epoch Days--------------------------------------------------5-8
Epoch Hours -----------------------------------------------5-8
Epoch Minutes--------------------------------------------5-8
Epoch Seconds-------------------------------------------5-8
Equidistant Cylindrical Projection--------3-10
Equinoctial Coordinate Type ------------------6-8
Euler Angles----------------------------------------------6-34
Exactly N----------------------------------------------------18-8
Exclusion Zone -----------------------------6-57, 7-12
Exiting STK----------------------------------------------------2-3
Export ---------------------------------------------------------15-6
Export Complete -------------------------------------15-6
External Applications ------------------------------2-15
External Attitude File--------------6-33, 7-6, 8-7
External File Formats---See Importing Files
F
Facilities
Access ---------------------------------------------------13-3
Attributes-------------------------------------------------9-6
Az-El Mask--------------------------------------9-6, 9-8
Basic ------------------------------------------------------9-10
Basic Properties
Position -----------------------------------------------9-2
City Database -------------------------------------14-2
Constraints
Basic--------------------------------------------------9-10
Satellite Tool Kit® User’s Manual
Index
Sun----------------------------------------------------9-13
Save with Children----------------------------2-10
Temporal-----------------------------------------9-16
Save without Children---------------------2-10
Description------------------------------------------2-17
First Pass Number------------------------------------6-40
Fixed Apogee Altitude ------------------------------8-5
Fixed Boresight ------------------------------------- 12-14
Fixed Coordinate System -----------6-12, 6-29
Fixed DeltaV ------------------------------------------------8-5
Fixed Sensor Pointing ------------------------- 12-10
Fixed Time of Flight -----------------------------------8-5
Flight Path Angle--------------------------6-11, 6-12
Focus Constants ----------------------------------- 12-17
Force Models---------------------------------6-15, 6-18
Frequency Unit----------------------------------------5-10
Display Times-----------------------------------------9-9
Facility Database--------------------------------14-5
Fixed Sensors----------------------------------- 12-12
Graphics Properties
Attributes --------------------------------------------9-6
Az-El Mask ------------------------------------------9-8
Display Times ------------------------------------9-9
Load TLE ------------------------------------------- 14-20
Position----------------------------------------------------9-2
Properties of-------------------------------------------9-1
Sun --------------------------------------------------------9-13
Temporal ---------------------------------------------9-16
Facility Database---------------------------14-1, 14-5
Querying the Database-------------------14-6
Search Results-------------------------------------14-7
Facility Database File Format ---------------C-32
Facility TLE ---------------------------------------------- 14-20
Field of View Constraint--------------------- 12-21
File Formats, External------------------------------- C-1
Files Menu----------------------------------------------------2-4
Close --------------------------------------------------------2-5
External Applications ------------------------2-15
Insert---------------------------------------------------------2-6
G
Gaussian Quadratures------------------------ 13-18
Geocentric Position------------------------ 9-5, 10-5
Geodetic Latitude------------------------------------6-11
Geodetic Position--------------------------- 9-3, 10-4
Global Attributes--------------------------------------5-14
Global Positioning System (GPS)---------18-2
GMT ------------------------------------------------------------6-53
Graph Styles------------------------------------------- 15-15
Options --------------------------------------------- 15-17
Graphics Properties---------------------------------2-16
Planets --------------------------------------------------11-4
Sensor------------------------------------------------ 12-17
Stars-------------------------------------------------------11-4
Insert as Link-------------------------------------------2-8
Graphs--------------------13-8, 0-1, 15-12, 18-12
Access ---------------------------------------------------13-8
Last Loaded--------------------------------------------2-8
Attributes-------------------------------- 15-13, 16-9
New---------------------------------------------------------2-6
Creating a New Graph ---------------- 15-15
Open -------------------------------------------------------2-5
Interval----------------------------------------------- 15-16
Printer Setup ---------------------------------------2-11
Layout------------------------------------------------ 15-17
Remove------------------------------------------------2-10
Polar--------------------------------------------------- 15-16
Save----------------------------------------------------------2-8
Polar 90--------------------------------------------- 15-16
Save As ----------------------------------------------------2-9
Style Properties-------------------------------- 15-15
Satellite Tool Kit® User’s Manual
I-7
Index
Time Periods ---------------------------------------15-3
Great Arc Propagator--------------------------7-2
Time XY---------------------------------------------- 15-16
Properties of-------------------------------------------7-1
XY 15-16
Route -------------------------------------------------------7-2
Gravitational Effects --------------------------------1-12
Grazing Altitude----------------------------6-56, 7-11
Grazing Angle-------------------------------6-55, 7-11
Great Arc-------------------------------------------------------7-2
Great Arc Propagator
Aricraft------------------------------------------------------7-2
Ground Vehicles ----------------------------------7-2
Ships---------------------------------------------------------7-2
Greenwich Mean Time (GMT)------------1-12
Grid Lines-----------------------------------15-18, 16-13
Ground Elevation--------------------------------- 13-24
Ground Elevation Angle ------------6-56, 7-12
Ground Sample Distance -----12-17, 12-26
Ground Tracks------------------------------------------5-15
Ground Tracks---------------------- 6-43, 6-57, 7-4
Ground Vehicles
Access ---------------------------------------------------13-3
Attitude----------------------------------------------------7-4
Attributes-------------------------------------------------7-6
Basic Properties
Attitude -----------------------------------------------7-4
Route---------------------------------------------------7-2
Step Size--------------------------------------------------7-2
H
h/k/p/q ---------------------------------------------------------6-9
Half Angles------------------------------------------------12-3
Half-Angle----------------------------------------------- 13-24
Half-Power Sensors---------------------------------12-4
Hammer-Aitoff Projection ---------------------3-11
Harris-Priester Atmosphere Model------1-12
Harris-Priester Atmospheric Model -------D-3
Harvard Revised Number------------------ 14-16
Header ---------------------------------------------------- 15-11
Help
From Property Window------------------17-3
Help Button ----------------------------------------------2-16
Help Menu----------------- 2-4, 2-18, 17-1, 18-1
Henry Draper Number----------------------- 14-16
High Speed--------------------------------------------------5-6
High-Resolution Maps Module------------1-15
HMTL Browser -----------------------------------------17-2
HPOP Module-------------------------------1-11, 6-15
HTTP Proxy---------------------------------------------------4-5
Hyperbolic Orbit--------------------------------------6-15
Constraints
Advanced-----------------------------6-54, 7-10
Basic--------------------------------------------------6-47
Sun----------------------------------------------------6-50
Temporal-----------------------------------------6-52
Description------------------------------------------2-17
Display Times-----------------------------------------7-8
Graphics Properties
Attributes --------------------------------------------7-6
Display Times ------------------------------------7-8
I-8
I
Icons, Object----------------------See Object Icons
Impact Azimuth-------------------------------------------8-5
Impact Elevation-----------------------------------------8-5
Impact Geocentric Latitude------------8-3, 8-5
Impact Geodetic Latitude----------------8-3, 8-5
Impact Longitude------------------------------8-3, 8-5
Importing Data into STK------------------------2-14
Importing Files-------------------------------------------- C-1
Attitude--------------------------------------------------- C-3
Satellite Tool Kit® User’s Manual
Index
J
Az-El--------------------------------------------------------- C-8
Bitmap --------------------------------------------------C-19
Database----------------------------------------------C-20
City ----------------------------------------------------C-29
Facility-----------------------------------------------C-32
Satellite ---------------------------------------------C-20
Star----------------------------------------------------C-34
Ephemeris --------------------------------------------- C-9
J2 Perturbation Propagators-------------------6-3
J2000 Coordinate System --------------------6-12
J4 Perturbation Propagators-------------------6-3
Joint Gravity Model (JGM)--------------------1-12
JPL DE403-------------------------------------------------11-4
Julian Date (JDate)-------------------------------------5-9
Julian Date Offset (JDateOff) ------------------5-9
Julian4 (UTCJ4)-------------------------------------------5-9
Pixmap--------------------------------------------------C-19
Planetary Ephemeris-------------------------C-17
K
TLE---------------------------------------------------------C-26
Keplerian Element--------------------------------------6-8
Torque--------------------------------------------------C-18
Inclination----------------------------6-6, 6-23, 14-10
Individual Object Access Report------- 18-10
Individual Strand Access Report ----------18-8
Inertial Coordinate System--------------------6-29
Inertially Fixed-------------------------------------------6-33
Initialize from Default Attitude--------------6-36
Insert As Link Function------------------------------2-8
Insert Point---------------------------3-17, 10-3, 12-8
Insert Window --------------------------------------------2-7
Inserting an Object------------------------------------2-6
Integrated Attitude----------------------------------6-35
International Atomic Time (TAI) -----------1-12
International Number------------------------- 14-10
Inter-Plane Spacing------------------------------ 13-27
Interval Graphs-------------------------------------- 15-16
IPC Preferences -------------------------------------------4-3
Allow ASync -------------------------------------------4-4
L
Labels----------------------------------------------------------5-15
Last Loaded Function -------------------------------2-8
Latitude
Cursor Position-----------------------------------3-17
Latitude Lines-----------------------------------------------3-7
Latitude Unit ---------------------------------------------5-10
Launch Vehicles
Access ---------------------------------------------------13-3
Attitude----------------------------------------------------8-6
Attributes-------------------------------------------------8-7
Basic Properties
Attitude -----------------------------------------------8-6
Constraints
Advanced-----------------------------6-54, 7-10
Allow Connect --------------------------------------4-4
Basic--------------------------------------------------6-47
Connection Method ---------------------------4-4
Sun----------------------------------------------------6-50
Default Connection Settings-------------4-4
Temporal-----------------------------------------6-52
Max Connections---------------------------------4-4
Contours----------------------------------------------8-10
Poll Period-----------------------------------------------4-4
Description------------------------------------------2-17
Display Times-----------------------------------------8-9
Graphics Properties
Satellite Tool Kit® User’s Manual
I-9
Index
Attributes --------------------------------------------8-7
Contours -----------------------------------------8-10
Display Times ------------------------------------8-9
Propagator---------------------------------------------8-3
Properties of-------------------------------------------8-1
Step Size --------------------------------------------------8-2
Swath------------------------------------------------- 13-23
Layout-----------------------------------------15-17, 16-13
Leading Ground Track --------------------------6-44
Leading Orbit Track --------------------------------6-44
Level Adding----------------------------------6-46, 8-11
Level Attributes------------------------------6-47, 8-12
Lifetime---------------------------------------------------- 13-14
Lifetime Module---------------------------------------1-14
Lighting--------------------------------------------------- 13-11
AER Report --------------------------------------- 13-13
Sun --------------------------------------------------------5-16
Time Data----------------------------------------- 13-13
Lighting Constraints---------------------6-52, 9-16
Line of Sight------------------------6-49, 9-13, 10-8
Link -----------------------------------------------------------------2-8
Lists --------------------------------------------------------------2-20
Load Method--------------------------------------------6-25
Auto Load--------------------------------------------6-25
File Insert----------------------------------------------6-25
File Load-----------------------------------------------6-25
Online Load----------------------------------------6-25
Load TLE ------------------------------------------------- 14-18
Load TLE
Open Database -----------------14-19, 14-21
Local Apparent-------------------6-53, 9-17, 10-9
Local Gregorian (LCLG)----------------------------5-8
Local Julian (LCLJ) -------------------------------------5-8
Longitude
Cursor Position-----------------------------------3-17
Longitude Lines ------------------------------------------3-7
Longitude of the Ascending Node-------6-6
I-10
Longitude Unit-----------------------------------------5-10
Long-term Orbit Predictor--------------See LOP
Loop at Time------------------------------------------------5-5
LOP--------------------------------------------------------------6-18
Advanced Settings ----------------------------6-20
LOP Module----------------------------------------------1-13
Lunar Elevation Angle-----------------6-51, 9-15
Lunar Exclusion Angle ----6-51, 6-52, 9-15,
12-22, 12-23
Lunar Gravity---------------------------------6-17, 6-20
M
Magnitude ------------------------------------------------11-2
Making Choices in STK---------------------------2-18
Map
Azimuthal Equidistant ----------------------3-11
Details------------------------------------------------------3-6
Equidistant Cylindrical----------------------3-10
Hammer-Aitoff------------------------------------3-11
Mercator ----------------------------------------------3-10
Miller------------------------------------------------------3-11
Mollweide--------------------------------------------3-11
Orthographic -------------------------------------3-11
Perspective ------------------------------------------3-10
Projections----------------------------------------------3-9
Sinusoidal---------------------------------------------3-11
Stereographic-------------------------------------3-11
Text Annotation---------------------------------3-15
Map Attributes---------------------------------------------3-5
Scroll Bars------------------------------------------------3-6
Show Status Bar------------------------------------3-6
Show Terrain Regions-------------------------3-6
Show Tool Bar---------------------------------------3-6
Map Background------------------------------------3-14
Map Details Tab------------------------------------------3-6
Satellite Tool Kit® User’s Manual
Index
Map Projection
Center Point----------------------------------------3-13
Map Projections------------------------------------------3-9
Map Properties--------------------------------------------3-5
Map Attributes---------------------------------------3-5
Map Background------------------------------3-14
Map Details --------------------------------------------3-6
Map Projection--------------------------------------3-9
Text Annotation ---------------------------------3-15
Map Properties Button------------------------------3-5
Map Window-------------------------------------3-1, 3-2
Animation Steps------------------------------------3-4
Windows---------------------------------------------2-17
Mercator Projection--------------------------------3-10
Meta Keys --------------------------------------------------2-21
Mid-Point----------------------------------------------------6-27
Miller Projection ---------------------------------------3-11
Missiles
Access ---------------------------------------------------13-3
Attitude----------------------------------------------------8-6
Attributes-------------------------------------------------8-7
Basic Properties
Attitude -----------------------------------------------8-6
Constraints
Map Properties Button------------------------3-5
Advanced-----------------------------6-54, 7-10
Scroll Bars------------------------------------------------3-6
Basic--------------------------------------------------6-47
Status Area-------------------------------------------3-17
Sun----------------------------------------------------6-50
Status Bar------------------------------------------------3-6
Temporal-----------------------------------------6-52
Tool Bar------------------------------------------3-3, 3-6
Contours----------------------------------------------8-10
Markers, Turn--------------------------------------------5-15
Mass -----------------------------------6-20, 6-40, 13-16
Mass Unit------------------------------------------------------5-9
Max Connections---------------------------------------4-4
Max TLE Limit--------------------------------------------6-25
Maximum Degree------------------------6-16, 6-19
Maximum Drag Altitude------------------------6-22
Maximum Order---------------------------6-16, 6-19
Mean Anomaly ------------------------------- 6-7, 6-23
Mean Equinox True Equator---------------6-13
Mean Longitude-----------------------------------------6-9
Mean Motion--------------------------------------------6-23
Mean Motion Dot-----------------------------------6-23
Mean of Date -------------------------------------------6-13
Mean of Epoch----------------------------------------6-13
Menu
Edit---------------------------------------------------------2-15
Description------------------------------------------2-17
Files-----------------------------------------------------------2-4
Help-------------------------------------------------------2-18
Tools------------------------------------------------------2-17
Satellite Tool Kit® User’s Manual
Display Times-----------------------------------------8-9
Graphics Properties
Attributes --------------------------------------------8-7
Contours -----------------------------------------8-10
Display Times ------------------------------------8-9
Propagator---------------------------------------------8-3
Properties of-------------------------------------------8-1
Step Size--------------------------------------------------8-2
Swath------------------------------------------------- 13-23
Mission----------------------------------------------------- 14-10
Mission Elapsed (MisElap) ------------------------5-9
Mixed Spherical Coordinate Type ------6-10
Modify Point------------------------3-17, 10-3, 12-8
Mollweide Projection -----------------------------3-11
Motion Dot Dot---------------------------------------6-23
MSGP4
Element Set Number -----------------------6-24
I-11
Index
TLE Load ----------------------------------------------6-24
Selecting Multiple ------------------------------2-18
MSGP4 Propagator---------------------------------6-22
Multiple Instance--------------------------------------15-9
Sensors -------------------------------------------------12-1
N
Ships---------------------------------------------------------7-1
Stars-------------------------------------------------------11-1
Target-------------------------------------------------------9-1
Nadir Alignment
ECF Velocity Constraint -------------------6-30
Oblateness Correction------------------------ 13-19
Obtain Archived Database ---------------- 14-13
Official Name----------------------------------------- 14-10
ECI Velocity Constraint---------------------6-30
OK Button -------------------------------------------------2-16
Orbit Normal Constraint------------------6-31
On-Line Manuals-------------------------------------17-9
Sun Constraint------------------------------------6-31
Online Operations-------------------------------------4-5
Network-----------------------------------------------------14-7
Online Update-------------------------------------- 14-12
New Objects------------------------------------------------2-6
Online Updates ---------------------------------------17-9
Nonorbiting Satellites --------------------------------6-1
Opening a Scenario----------------------------------2-5
Nonorbiting Vehicles -----------------------7-1, 8-1
Option Menus------------------------------------------2-20
Nutation-----------------------------------------------------1-12
Orbit Count Limit---------------------------------- 13-18
Orbit Epoch ------------------------------------- 6-4, 6-23
Orbit Lifetime------------------------------ See Lifetime
O
Orbiting Satellites----------------------------------------6-1
Object Description14-5, 14-8, 14-14, 14-17, 14-22 Orbits ----------------------------------------------------------5-15
Object Icons-------------------------------------------------2-5
Orbits per Calculation ------------------------- 13-18
Object Menu -----------------------------------------------2-5
Ordering Chain Objects------------------------18-4
Objects
Orientation Type -------------------------------------6-34
Aircraft------------------------------------------------------7-1
Orthographic Projection-----------------------3-11
Describing -------------------------------------------2-17
Osculating Ellipse ------------------------------------6-14
Output Attitude File--------------------------------6-36
Facility ------------------------------------------------------9-1
Output Device -----------------------------------------2-12
Ground Vehicles ----------------------------------7-1
Owner----------------------------------------------------- 14-10
Inserting --------------------------------------------------2-6
Owner/Mission File Format -----------------C-24
Inserting as Links-----------------------------------2-8
Missiles-----------------------------------------------------8-1
P
New---------------------------------------------------------2-6
Page Layout-----------------------------------2-12, 2-14
Pair-wise Analysis ----------------------- 18-2, 18-10
Parabolic Antennas---------------------------------12-4
Parabolic Orbit------------------------------------------6-15
Parallax -------------------------------------------------------11-3
Pass--------------------------------------------------------------6-42
Pass Break--------------------------------------------------6-38
Pass Labels-------------------------------------------------5-15
Planets --------------------------------------------------11-1
Properties---------------------------------------------2-15
Removing--------------------------------------------2-10
Satellites---------------------------------------------------6-1
Saving------------------------------------------------------2-8
I-12
Satellite Tool Kit® User’s Manual
Index
Paste Function------------------------------------------2-15
Penumbra ----------------------------------- 5-17, 13-12
Perigee ---------------------------------------------------- 14-10
Perigee Altitude-------------------------------------------6-5
Perigee Radius---------------------------------------------6-5
Period------------------------------------------------------- 14-10
Persistence---------------------------------------------- 12-19
Perspective Projection----------------------------3-10
Physical Data---------------------------------------------6-20
Pitch-------------------------------------------------------------6-34
Pixmap File Format---------------------------------C-19
Planetary Ephemeris File Format--------C-17
Planets --------------------------------------------------------11-1
Access ---------------------------------------------------13-3
Attributes----------------------------------------------11-4
Basic Properties
Definition-----------------------------------------11-3
Definition---------------------------------------------11-3
Description------------------------------------------2-17
Graphics Properties---------------------------11-4
Attributes -----------------------------------------11-4
Properties of----------------------------------------11-1
Pointing
Target Times ------------------------------------ 12-15
Pointing a Sensor ------------------------------------12-9
Polar 90 Graphs------------------------------------ 15-16
Polar Graphs------------------------------------------ 15-16
Polar Motion -----------------------------------------------D-1
Polar Plot-------------------------------------------------------B-3
Poll Period-----------------------------------------------------4-4
Population-------------------------------------------------14-4
Port-----------------------------------------------------------------4-5
Posigrade------------------------------------------------------6-9
Position
Cartesian -------------------------------------------------9-4
Geocentric----------------------------------------------9-5
Geodetic-------------------------------------------------9-3
Spherical--------------------------------------------------9-4
Targets-----------------------------------------------------9-2
Power Unit---------------------------------------------------5-9
Precessing, Secularly-------------------------------6-15
Precession--------------------------------------------------1-12
Printer Command -----------------------------------2-12
Printer Setup ---------------------------------------------2-11
2D Map------------------------------------------------2-11
Attributes----------------------------------------------2-14
Page Layout----------------------------------------2-14
Reports & Graphs------------------------------2-13
Projection------------------------------------------------ 12-18
Azimuthal Equidistant ----------------------3-11
Equidistant Cylindrical----------------------3-10
Hammer-Aitoff------------------------------------3-11
Mercator ----------------------------------------------3-10
Miller------------------------------------------------------3-11
Mollweide--------------------------------------------3-11
Orthographic -------------------------------------3-11
Perspective ------------------------------------------3-10
Sinusoidal---------------------------------------------3-11
Stereographic-------------------------------------3-11
Projection, Map ------------------------------------------3-9
Propagation Delay----------------------------------9-13
Propagators
Ballistic------------------------------------------------------8-3
Great Arc-------------------------------------------------7-2
J2 Perturbation--------------------------------------6-3
J4 Perturbation--------------------------------------6-3
MSGP4 -------------------------------------------------6-22
Cylindrical -----------------------------------------------9-5
STK External-----------------------------------------6-27
Facilities----------------------------------------------------9-2
Two-Body-----------------------------------------------6-3
Satellite Tool Kit® User’s Manual
I-13
Index
Proper Motion------------------------------------------11-2
Properties
Dynamic Display--------------------------------16-5
Province -----------------------------------------------------14-4
Proximity ------------------------------------------------- 13-29
Reports -------------------------------------------------15-6
Q
Strip Charts --------------------------------------- 16-10
Quaternions-----------------------------------6-29, 6-34
Quick Save----------------------------------------------------4-3
Quitting STK-------------------------------------------------2-3
Properties Menu-----------------------------------------2-4
Basic ------------------------------------------------------2-16
Constraints-------------------------------------------2-16
Graphics-----------------------------------------------2-16
Properties of a(n) . . .
STK Application--------------------------------------4-1
Properties of a(n) …
Aircraft------------------------------------------------------7-1
Facility ------------------------------------------------------9-1
Ground Vehicle------------------------------------7-1
Launch Vehicle -------------------------------------8-1
Missile-------------------------------------------------------8-1
Planet----------------------------------------------------11-1
Satellite-----------------------------------------------------6-1
Scenario --------------------------------------------------0-1
Sensor---------------------------------------------------12-1
R
RAAN Spread----------------------------------------- 13-27
Radiation Pressure
Solar ------------------------------------------------------6-20
Radio Buttons-------------------------------------------2-20
Radius ---------------------------------------------------------11-4
Range ----------------------------------------------6-48, 9-12
Range Rate-------------------------------------6-48, 9-12
Rate ----------------------------------------------------------------7-4
Real-Time-------------------------------------------------------5-6
Rectangular Sensor--------------------------------12-8
Reference Plane, Custom Sensor-----------B-2
References
Online---------------------------------------------------17-9
Constellation ----------------------------------18-6
Reflection Coeffient------------------------------ 13-16
Refresh Delta -----------------------------------------------5-6
Remove------------------------------------------------------2-10
Remove Accesses --------------------------------- 13-29
Remove Constellation------------------------- 13-27
Removing Access ------------------------------------13-9
Removing an Object------------------------------2-10
Renaming a Chain----------------------------------18-3
Reports ----------------------------------------------------------0-1
Access ---------------------------------------------------13-6
Constraints-------------------------------------------2-16
AER------------------------------------------ 13-7, 13-13
Graphics-----------------------------------------------2-16
Complete Chain Access---------------- 18-11
Help Button ----------------------------------------17-3
Content------------------------------------------------15-7
How to Use-----------------------------------------2-16
Customizing----------------------------------------13-8
Tabs-------------------------------------------------------2-16
Generating a Report ------------------------18-8
Ship-----------------------------------------------------------7-1
Star---------------------------------------------------------11-1
Target-------------------------------------------------------9-1
Properties, Object------------------------------------2-15
Property Windows----------------------------------2-16
Basic ------------------------------------------------------2-16
Chain------------------------------------------------18-3
I-14
Satellite Tool Kit® User’s Manual
Index
Header ---------------------------------------------- 15-11
Attitude Type Selection --------------------6-29
Individual Object Access--------------- 18-10
Attributes----------------------------------------------6-41
Individual Strand Access ------------------18-8
Basic Properties
Lighting Times--------------------------------- 13-13
Attitude --------------------------------------------6-28
Properties---------------------------------------------15-6
Attitude --------------------------------------------6-28
Time Periods ---------------------------------------15-3
Pass Break ---------------------------------------6-38
Title ---------------15-8, 15-11, 15-17, 15-18
Reports & Graphs
Printer Setup ---------------------------------------2-13
Resolution----------------------------------------------- 12-16
Resolution Constraints
Sensors ---------------------------------------------- 12-25
Retrograde ---------------------------------------------------6-9
Right Ascension --------------6-23, 11-2, 14-16
Right Ascension Angle---------------------------6-34
Right Ascension of the Ascending
Node ----------------------------------------------- 6-6, 6-11
Roll---------------------------------------------------------------6-34
Rotating Atmosphere-------------------------- 13-19
Route -------------------------------------------------------------7-2
Runge-Kutta-Fehlberg----------------------------1-13
S
SAO Catalog Number------------------------- 14-16
Satellite Database--------------------------14-1, 14-8
Close Approach Tool--------------------- 13-29
Object Description------------------------- 14-14
Online Update-------------------------------- 14-12
Querying the Database---------------- 14-10
Search Results---------------------------------- 14-11
Satellite Database File Format--------------C-20
Owner/Mission File --------------------------C-24
BasicProperties
Mass--------------------------------------------------6-40
Constraints
Advanced-----------------------------6-54, 7-10
Basic--------------------------------------------------6-47
Sun----------------------------------------------------6-50
Temporal-----------------------------------------6-52
Constraints Properties ----------------------6-47
Contours----------------------------------------------6-45
Coordinate Epoch -------------------------------6-4
Coordinate System----------------------------6-12
Coordinate Type-----------------------------------6-4
Custom-------------------------------------------------6-27
Description------------------------------------------2-17
Display Times--------------------------------------6-44
Graphic Properties
Attributes -----------------------------------------6-41
Contours -----------------------------------------6-45
Display Times ---------------------------------6-44
Pass---------------------------------------------------6-42
Integrated Attitude----------------------------6-35
J2 Propagator----------------------------------------6-3
J4 Propagator----------------------------------------6-3
Satellite TLE--------------------------------------------- 14-18
Satellites
Access ---------------------------------------------------13-3
Load TLE ------------------------------------------- 14-18
Attitude-------------------------------------------------6-28
Nonorbiting-------------------------------------------6-1
Satellite Tool Kit® User’s Manual
Mass ------------------------------------------------------6-40
MSGP4 -------------------------------------------------6-22
I-15
Index
Orbit Epoch -------------------------------------------6-4
Graphic Properties
Orbiting---------------------------------------------------6-1
Global Attributes----------------------------5-14
Orientation Types------------------------------6-34
Sun Lighting-----------------------------------5-16
Pass--------------------------------------------------------6-42
Opening-------------------------------------------------2-5
Pass Break--------------------------------------------6-38
Sun Lighting ---------------------------------------5-16
Properties of-------------------------------------------6-1
Terrain---------------------------------------------------5-12
Satellite Database-------------------------------14-8
Time Period--------------------------------------------5-2
Selection Targets--------------------------------6-36
Units---------------------------------------------------------5-7
Step Size --------------------------------------------------6-3
Search Constraint
Close Approach Tool--------------------- 13-32
Swath------------------------------------------------- 13-23
Target Pointing ----------------------------------6-36
Two-Body Propagator ------------------------6-3
Walker Constellation---------------------- 13-26
Save----------------------------------------------------------------2-8
Save As ----------------------------------------------------------2-9
Save Period---------------------------------------------------4-3
Save Prefs------------------------------------------------------4-2
Save Vehicle Ephemeris ---------------------------4-2
Save with Children----------------------------------2-10
Save without Children ---------------------------2-10
Saving an Object----------------------------------------2-8
Scenarios
Animating--------------------------------------------3-18
Animation-----------------------------------------------5-4
Basic Properties
Search Tolerances-------------------------------- 13-33
Secularly Precessing--------------------------------6-15
Select File ---------------------------------------------------2-14
Select Targets--------------------------------------------6-36
Semimajor Axis-----------------------------------6-5, 6-9
Sensor Attributes----------------------------------- 12-17
Sensors --------------------------------------------5-15, 12-1
Access ------------------------------------- 13-3, 13-10
Basic Properties ----------------------------------12-2
Definition ----------------------------------------12-2
Pointing-------------------------------------------12-9
Resolution ------------------------------------ 12-16
Conic-----------------------------------------------------12-3
Constraints
Advanced------------------------------------- 12-24
Animation ------------------------------------------5-4
Sun------------------------------------------------- 12-22
Database-----------------------------------------5-11
Temporal-------------------------------------- 12-24
Terrain----------------------------------------------5-12
Constraints---------------------------------------- 12-21
Time Period ---------------------------------------5-2
Constraints Properties
Units-----------------------------------------------------5-7
Resolution ------------------------------------ 12-25
Closing-----------------------------------------------------2-5
Custom Patterns --------------------------------12-6
Database----------------------------------------------5-11
Definition---------------------------------------------12-2
Description------------------------------------------2-17
Description------------------------------------------2-17
Global Attributes--------------------------------5-14
Display Times----------------------------------- 12-20
I-16
Satellite Tool Kit® User’s Manual
Index
Facility-Based------------------------------------ 12-12
Route -------------------------------------------------------7-2
Graphics Properties------------------------ 12-17
Step Size--------------------------------------------------7-2
Display Times ------------------------------ 12-20
Shortcut Keys--------------------------------------------2-21
Show Scroll Bars -----------------------------------------3-6
Sinusoidal Projection ------------------------------3-11
Site Name--------------------------------------------------14-6
Slew Time --------------------------------------------------6-37
Small Distance Unit---------------------------------5-10
Solar Beta Angle --------------------------------------6-55
Solar Data----------------------------------------------- 13-17
Solar Exclusion Angle-----------------6-51, 9-15,
12-22, 12-23
Solar Gravity----------------------------------------------6-17
Solar Radiation Pressure -1-12, 6-17, 6-20,
D-2
Cross-Sectional Area--------------------------6-20
Projection------------------------------------- 12-18
Half-Power-------------------------------------------12-4
Pointing------------------------------------------------12-9
Projection------------------------------------------ 12-18
Properties of----------------------------------------12-1
Rectangular-----------------------------------------12-8
Resolution----------------------------------------- 12-16
Swath------------------------------------------------- 13-25
Target-Based------------------------------------ 12-12
Sensors, Custom-----------------------------------------B-1
Server-------------------------------------------------------------4-5
Ships
Access ---------------------------------------------------13-3
Attitude----------------------------------------------------7-4
Attributes-------------------------------------------------7-6
Basic Properties
Attitude -----------------------------------------------7-4
Route---------------------------------------------------7-2
Constraints
Solar/Lunar Obstruction-------------6-52, 9-16
Specular Reflection----------------------------------1-12
Spherical Coordinate Type -------------------6-11
Spherical Position --------------------------- 9-4, 10-4
Spin About Sun Vector--------------------------6-33
Spinning-----------------------------------------------------6-33
Spinning About Nadir----------------------------6-33
SSC Number ------------------------------- 6-23, 14-10
Star Database ----------------------------- 14-1, 14-14
Description Tab------------------------------- 14-17
Advanced-----------------------------6-54, 7-10
Querying the Database---------------- 14-15
Basic--------------------------------------------------6-47
Search Results---------------------------------- 14-17
Sun----------------------------------------------------6-50
Description------------------------------------------2-17
Star Database File Format---------------------C-34
Stars-------------------------------------------------------------11-1
Access ---------------------------------------------------13-3
Display Times-----------------------------------------7-8
Attributes----------------------------------------------11-4
Graphics Properties
Basic Properties
Temporal-----------------------------------------6-52
Attributes --------------------------------------------7-6
Definition ----------------------------------------11-2
Display Times ------------------------------------7-8
Definition---------------------------------------------11-2
Great Arc Propagator--------------------------7-2
Description------------------------------------------2-17
Properties of-------------------------------------------7-1
Graphics Properties---------------------------11-4
Satellite Tool Kit® User’s Manual
I-17
Index
Attributes -----------------------------------------11-4
Properties of----------------------------------------11-1
Star Database----------------------------------- 14-14
Starting STK---------------------------------------------------2-3
State-------------------------------------------------------------14-4
Status-------------------------------------------------------- 14-10
Status Bar------------------------------------------ 3-6, 3-17
Step Count --------------------------------------------- 12-19
Step Size
Aircraft------------------------------------------------------7-2
Ground Vehicles ----------------------------------7-2
Launch Vehicles------------------------------------8-2
missiles-----------------------------------------------------8-2
Satellites---------------------------------------------------6-3
Ships---------------------------------------------------------7-2
Stereographic Projection-----------------------3-11
STK
Exiting ------------------------------------------------------2-3
STK Dynamic Display Window------------16-2
STK External Propagator------------------------6-27
STK Files, Importing----------------------------------- C-1
STK Hierarchical Structure ------------------------2-3
STK PRO---------------------------------------------------------1-9
Advanced Analysis -------------------------------1-9
High-Resolution Maps Module------1-15
stkActiveTLE.sd File----------------------------------C-21
stkActiveTLE.tce File---------------------------------C-25
stkActiveTLE.wr File---------------------------------C-23
stkCityDb.cc File---------------------------------------C-31
stkCityDb.cd File --------------------------------------C-30
stkCityDb.gd File--------------------------------------C-32
stkFacility Database Files------------------------C-32
stkFacility.cc File ---------------------------------------C-33
stkFacility.fd File----------------------------------------C-33
stkFacility.gd File --------------------------------------C-34
stkStarDb Database Files -----------------------C-34
stkStarDb.bc File---------------------------------------C-36
stkStarDb.bd File--------------------------------------C-35
stkStarDb.bn File--------------------------------------C-36
stkStarDb.gd File--------------------------------------C-37
Strands--------------------------------------------------------18-8
Strip Charts ------------------------------------------------16-1
Content--------------------------------------------- 16-11
Layout------------------------------------------------ 16-13
Properties------------------------------------------ 16-10
Title ----------------------------------------------------- 16-13
Style Properties-------------------------------------- 15-15
Content--------- 15-7, 15-15, 16-6, 16-11
Header ---------------------------------------------- 15-11
Layout-----------------------------------15-17, 16-13
Options ------------15-8, 15-9, 16-7, 16-12
HPOP Module------------------------------------1-11
Summary Options-------------------------- 15-10
Lifetime Module---------------------------------1-14
Subsolar Point-------------------------------------------5-16
Summary Options-------------------------------- 15-10
Sun
Facilities ------------------------------------------------9-13
LOP Module----------------------------------------1-13
Terrain Module ----------------------------------1-14
STK Report Tool window ----------------------15-2
STK Strip Chart Window------------------------16-2
STK Structure------------------------------------------------2-3
STK Tools----------------------------------------------------13-1
stkActiveTLE Database Files-------------------C-21
stkActiveTLE.fr File------------------------------------C-23
stkActiveTLE.gd File---------------------------------C-26
stkActiveTLE.om File--------------------------------C-24
I-18
Targets--------------------------------------------------9-13
Sun Alignment
ECI Z Axis Constraint-------------------------6-32
Eliptical Normal Constraint -------------6-31
Nadir Constraint --------------------------------6-31
Sun Constraints
Satellite Tool Kit® User’s Manual
Index
Aircraft---------------------------------------------------6-50
Sun----------------------------------------------------9-13
Ground Vehicles -------------------------------6-50
Temporal-----------------------------------------9-16
Launch Vehicles---------------------------------6-50
Description------------------------------------------2-17
Missiles--------------------------------------------------6-50
Display Times-----------------------------------------9-9
Satellites------------------------------------------------6-50
Facility Database--------------------------------14-5
Sensors ---------------------------------------------- 12-22
Fixed Sensors----------------------------------- 12-12
Ships------------------------------------------------------6-50
Graphics Properties
Sun Elevation Angle --------------------6-51, 9-14
Sun Ground Elevation Angle----6-51, 9-14
Sun Lighting ---------------------------------------------5-16
Display Altitude ----------------------------------5-17
Sunlight--------------------------------------------------- 13-12
Swath------------------------------------------------------- 13-23
Edge Limits--------------------------------------- 13-24
Attributes --------------------------------------------9-6
Az-El Mask ------------------------------------------9-8
Display Times ------------------------------------9-9
Load TLE ------------------------------------------- 14-20
Position----------------------------------------------------9-2
Properties of-------------------------------------------9-1
Filled Limits --------------------------------------- 13-24
Sun --------------------------------------------------------9-13
Switching Method ----------------------------------6-27
Temporal ---------------------------------------------9-16
T
Tabs-------------------------------------------------------------2-16
TAI----------------See International Atomic Time
Target Pointing ----------------------------------------6-36
Target Times ---------------------------------------6-37
TCA--------------------------------------------------------------6-27
TCPSocket-----------------------------------------------------4-4
Temporal Constraints-----------------------------6-52
Aircraft---------------------------------------------------6-52
Area Targets----------------------------------------10-9
Facilities ------------------------------------------------9-16
Target Schedule---------------------------------------6-37
Target Times ------------------------------- 6-37, 12-15
Targeting a Sensor------------------------------- 12-13
Targets
Access ---------------------------------------------------13-3
Ground Vehicles -------------------------------6-52
Attributes-------------------------------------------------9-6
Sensors ---------------------------------------------- 12-24
Az-El Mask--------------------------------------9-6, 9-8
Ships------------------------------------------------------6-52
Basic ------------------------------------------------------9-10
Basic Properties
Position -----------------------------------------------9-2
City Database--------------------------------------14-2
Constraints
Basic--------------------------------------------------9-10
Satellite Tool Kit® User’s Manual
Launch Vehicles --------------------------------6-52
Missiles--------------------------------------------------6-52
Satellites------------------------------------------------6-52
Targets--------------------------------------------------9-16
Terrain Module ----------------------------------------1-14
Terrain Tab ------------------------------------------------5-12
Terrestrial Dynamic Time (TDT) -----------1-12
Text Annotation---------------------------------------3-15
Text Annotation,Map-----------------------------3-15
Third-Body Gravity ----------------------------------6-17
I-19
Index
Tick Marks ----------------------------------15-18, 16-13
Time Past Ascending Node---------------------6-7
Time Past Perigee ---------------------------------------6-7
Time Period------------------------------------5-2, 13-31
Time Periods
Graphs--------------------------------------------------15-3
Reports -------------------------------------------------15-3
Time Step------------------------------------------------------5-6
Time Steps, Animation ------------------------------3-4
Time Unit ------------------------------------------------------5-8
Time XY Graphs ------------------------------------ 15-16
TLE----------------------------------------------------6-22, 6-24
Advanced --------------------------------------------6-26
Load--------------------------------------------------- 14-18
Load Method--------------------------------------6-25
TLE File--------------------------------------------------------6-25
TLE File Format----------------------------- C-26, C-28
TLE Load ----------------------------------------------------6-24
TLE Selection---------------------------------------------6-26
Toggle Buttons ----------------------------------------2-19
Tool Bar--------------------------------------- 3-1, 3-3, 3-6
Animation Steps------------------------------------3-4
Strip Charts ------------------------------------------16-1
Swath------------------------------------------------- 13-23
Walker ----------------------------------------------- 13-26
Tools Menu-------------------------------------- 2-4, 2-17
Torque File ------------------------------------------------6-35
Torque File Format ---------------------------------C-18
Tracking Boresight ------------------------------- 12-14
Tracks
Ground ---------------------------- 6-43, 6-57, 7-4
Vehicle--------------------------------------------------3-18
Trailing Ground Track ----------------------------6-44
Trailing Orbit Track----------------------------------6-44
True Anomaly----------------------------------------------6-7
True of Date----------------------------------------------6-13
True of Epoch ------------------------------------------6-13
Turn Markers---------------------------------------------5-15
Turn Radius--------------------------------------------------7-4
Two-Body Propagators-----------------------------6-3
Two-Line Element-----------------------------------14-8
U
Map Properties--------------------------------------3-5
Umbra ------------------------------------------ 5-17, 13-12
Units---------------------------------------------------------------5-7
Angle -------------------------------------------------------5-9
Message Box------------------------------------------3-3
Date Format ------------------------------------------5-9
Status Area----------------------------------------------3-3
Distance --------------------------------------------------5-8
Status Bar---------------------------------------------3-17
Frequency-------------------------------------------5-10
Tools------------------------------------------------------------13-1
Access ---------------------------------------------------13-3
Latitude ------------------------------------------------5-10
Buttons----------------------------------------------------3-3
Close Approach ------------------------------ 13-29
Dynamic Display--------------------------------16-1
Graphs-------------------------0-1, 15-12, 18-12
Lifetime---------------------------------------------- 13-14
Lighting--------------------------------------------- 13-11
Remove Accesses --------------------------- 13-29
Reports ---------------------------------------- 0-1, 18-8
I-20
Longitude--------------------------------------------5-10
Mass ---------------------------------------------------------5-9
Power------------------------------------------------------5-9
Small Distance------------------------------------5-10
Time ---------------------------------------------------------5-8
Universal Time Coordinated (UTC) ----1-12
UnixSocket----------------------------------------------------4-4
Update Database--------------------------------- 14-13
Satellite Tool Kit® User’s Manual
Index
User Manuals Online -----------------------------17-9
Using STK Tools----------------------------------------13-1
UTC Gregorian--------------------------------------------5-8
UTC Julian ----------------------------------------------------5-8
V
Vehicle
Attributes-------------------------------------------------7-6
Graphic Properties
Attributes --------------------------------------------7-6
Vehicle Tracks-------------------------------------------3-18
Vehicles
Nonorbiting----------------------------------7-1, 8-1
Verbose---------------------------------------------------------4-4
Visible Sides-----------------------------------------------6-43
Visual Magnitude --------------------------------- 14-16
W
Walker Constellation---------------------------- 13-26
Waypoints ----------------------------------------------------7-3
Windows Menu ----------------------------- 2-4, 2-17
X
X Real-Time---------------------------------------------------5-6
XY Graphs----------------------------------------------- 15-16
Y
Yaw -------------------------------------------------------------6-34
Yaw to Nadir---------------------------------------------6-32
YPR Angles-------------------------------------------------6-34
Z
Zoom In --------------------------------------- 15-13, 16-9
Zoom Out ----------------------------------- 15-13, 16-9
Satellite Tool Kit® User’s Manual
I-21
127(6
Satellite Tool Kit® User’s Manual
I-22
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