MIDG Series INS/GPS User Manual

MIDG SERIES INS/GPS

USER MANUAL

09 January 2012

TABLE OF CONTENTS

Section

7.

6.

4.

5.

1.

2.

3.

A.

B.

C.

D.

9.

E.

8.

Heading

Introduction..................................................................................................................................................

Getting Started.............................................................................................................................................

MIDG Series INS/GPS Software and Utilities..........................................................................................

3.1 Installing the Software and Utilities................................................................................................

GPS Antenna Specifications........................................................................................................................

4.1 Active GPS Antennas........................................................................................................................

4.2 Passive GPS Antennas......................................................................................................................

4.3 Installing and Using the MIDG Series INS/GPS Patch Antenna..................................................

Installing and Using the SLC2JUSB Interface Cable...............................................................................

5.1 SLC2JUSB Driver Installation.........................................................................................................

5.1.1 Using the SLC2JUSB Interface Cable...............................................................................

5.2 Using the SLC2J09SF Interface Cable............................................................................................

5.2.1 Connecting the SLC2J09SF Interface Cable.....................................................................

User Supplied Interface...............................................................................................................................

6.1 General Connections.........................................................................................................................

6.1.1

6.1.2

Power Connections..............................................................................................................

Digital Ground Connections...............................................................................................

6.2 RS - 422 Data Connections...............................................................................................................

6.3 RS - 232 Data Connections...............................................................................................................

6.4 1 Pulse - Per - Second Output...........................................................................................................

6.4.1 Trigger Input........................................................................................................................

MIDG Series INS/GPS Dimensions and Mounting..................................................................................

7.1 Physical Dimensions..........................................................................................................................

7.1.1 Physical Characteristics......................................................................................................

7.2 Mounting the MIDG Series INS/GPS..............................................................................................

7.2.1 Hard Mounting the MIDG Series INS/GPS......................................................................

7.2.2 Soft Mounting the MIDG Series INS/GPS........................................................................

7.3 Mounting Orientation.......................................................................................................................

7.3.1 Orientation Correction........................................................................................................

MIDG Series INS/GPS Messages................................................................................................................

8.1 Microbotics Binary Protocol.............................................................................................................

8.1.1 Microbotics Binary Protocol Message Contents...............................................................

8.1.2 Fletcher Checksum..............................................................................................................

Help and Support.........................................................................................................................................

ATTACHMENT A - SLC2JUSB.................................................................................................................

ATTACHMENT B - MIDG II Message Specification FW 2.1.x & Higher.............................................

ATTACHMENT C - MIDG Series INS/GPS Specifications....................................................................

ATTACHMENT D - GPS Antenna Specifications....................................................................................

ATTACHMENT E - Installation File Directory Tree...............................................................................

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1 Introduction. Congratulations on your purchase of the MIDG Series INS/GPS; the smallest and most advanced Inertial

Navigation System (INS) in its class. This guide is designed as a quick start guide and will get your MIDG Series INS/GPS up and running. Along with the MIDG Series INS/GPS is a whole host of tool and software which enables you to quickly custom tailor the MIDG's operation to fit your specific needs.

The MIDG Series INS/GPS is an inertial navigation system (INS) using GPS-aiding. The on-board GPS receiver can track up to sixteen satellites when the GPS antenna has a clear view of the sky and is WAAS and EGNOS compliant. The GPS provides a three-dimensional fix, allowing the INS to determine its current position within two meters. The system also contains an array of sensors, which, coupled with a GPS receiver, provide the input data to the internal microprocessor running an optimized Kalman filter. This Kalman filter considers all the data provided, estimates and adjusts for the sensor errors, and determines the vehicle’s position, velocity, and attitude.

The MIDG Series INS/GPS provides a serial data stream which can be easily integrated with the user control computer and/or control center. Data outputs can be polled or automatically updated for position, attitude, etc., at intervals up to 50 Hz.

2 Getting Started. The MIDG Series INS/GPS will have been shipped several other items. Some of these items are optional and depending on your order, you may, or may not, have received them. Figure 1 shows the MIDG Series INS/GPS with all of the available accessories. Please verify the order contents with the purchase order to ensure that all items order ed have been received.

A standard MIDG Series INS/GPS will come with the following items:

A. MIDG Series INS/GPS: SIS90031C,

B.

SIS90031C-SR, SIS90031C-G

(Dependant on the model ordered.)

MIDG Utilities CD-ROM: Contains all of the software, utilities, and documentation for the MIDG Series

C.

D.

E.

INS/GPS

Mating Connector: An 18", 30 AWG

Omnetics mating connector with pigtail and stainless capturing screw.

Mounting Screws: Nonmagnetic stainless mounting screws 0-80 x 3/16"

Hex Wrench: A 0.9mm hex wrench for use with the capturing screw on the mating connector.

Optional MIDG Series INS/GPS accessories which may be ordered are:

F.

Figure 1. MIDG Series INS/GPS with Accessories

SLC2JUSB: A pre-built MIDG Mating/USB interface cable to provide power and data connections to the

G.

H.

I.

MIDG Series INS/GPS.

SLC2J09SF: A pre-built interface cable provides power and data connections to the MIDG Series

INS/GPS to a PC's RS232 serial port and a 10-32 VDC 100 mW external power supply.

Active GPS Antenna: A five (5) volts, Hi-Gain/Lo-Noise GPS patch antenna.

SLC10232: A Serial Voltage Level Converter for RS232 to/from RS422 or TTL format.

Copyright Microbotics Inc. 2011

Page 1 of 13

3 MIDG Series INS/GPS Software and Utilities . The software and utilities package for the MIDG Series INS/GPS contains many tools to configure, optimize, and update the MIDG Series INS/GPS as well as all of the needed documentation for understanding how to perform various functions and operations.

Software included on the CD:

A.

B.

MIDG II Display Utility: Used to configure, display, and optimize the MIDG output

MIDG II Flash Loader: Used to update the MIDG Series INS/GPS firmware

C.

D.

INS Parser: Used to parse inertial navigation data recorded from the MIDG while in INS Mode for post operation analysis.

II Parser: Used to parse inertial measurement data recorded from the MIDG while in IMU Mode for post operation analysis.

Tools included on the CD:

F. MatLab™ Files (MFiles): MatLab™ program files for various mapping and plotting of route/and or flight

G. information. There are several examples which will enable the user to become familiar with the MIDG II binary output.

Interface Software: Contains the "C" language tools needed to interface a computer to the MIDG Series

INS/GPS. This tool kit may be adapted for flight, remote control systems, radio transmission, and/or employed in robotic interfaces.

Documentation included on the CD:

H.

I.

J.

Application Notes: Contains information about how the MIDG

Series INS/GPS uses the different operational modes such as

Vertical Gyro (VG) and Inertial Navigation System (INS).

Instructions: Contains instructions on how to use all of the MIDG

Series INS/GPS software as well as how to magnetically calibrate and set the accelerometer biases for the MIDG Series INS/GPS.

Message Specification: Contains a current version of the MIDG

Series Message Specification.

3.1 Installing the Software and Utilities. The MIDG Series INS/GPS software and utilities are all contained in a single installer package. The following steps will guide the user through the software and utilities installation process.

1. Place the MIDG Software and Utilities CD into a CD reader.

Figure 2 shows the root of the CD-ROM. As shown, the root of the

CD-ROM will contain the two (2) folders and a document file listed below:

A. Vista-Win 7: Contains Window Vista and Windows 7

B.

C. installer.

Win-2K to XP-64: Contains Windows 2K to XP64 installer.

READ ME FIRST.doc: Instructs on how to identify

Windows® version.

Figure 2. MIDG Series INS/GPS

CD-ROM Contents.

2. Open the folder which contains the specified version of

Windows®. Figure 3 shows the contents of the opened folder. The selected folder will contain three (3) files: (Win-2K to XP-64 used as an example)


Installation Programs

(Win 2k to Win XP-64)


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A.

B.

C.

Drivers Win2K to XP64.exe: An installer package for the driver files for the SLC2JUSB Cable

(optional).

Win2K - WinXP64.msi: The installer package for the MIDG Series INS/GPS Software and

Utilities.

READ ME.doc: A document file detailing all Windows® versions which are supported.

3.

4.

Select the installer file ("msi" extension) to begin the

installation process.

On the "Welcome" screen, press the "Next" button to

continue the installation process (Figure 4).

Figure 4. Installation "Welcome" Screen

5.

6.

Read the End User License Agreement (EULA). Select the "I

accept the terms in the License Agreement" radio button.

Figure 5 shows the End User License Agreement screen. The

"Next" button will become active. If the license agreement radio button is not selected the installation will not continue.

Select the "Next" button at the bottom of the EULA screen to

continue. A copy of the EULA agreement is installed with the rest of the software and documentation.

Figure 5. EULA Agreement Screen

7. Select the destination folder for the installation

program. Figure 6 shows the default path for the installation. However, the user may specify any location desired.

8. Press the "Next" button at the bottom of the screen to continue with the installation.

9.

Figure 6. Select destination folder screen

Press the "Install" button at the bottom of the screen to

continue with the installation (Figure 7). At this point the

"Installer" screen will display the progress of the installer as it installs several files and programs on to hard drive of the PC or laptop. The location of these files will be where ever the installation location was designated in Step 7.

Figure 7. Ready Installation screen


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Once the installation is finished, the "Finished" screen (Figure 8) will appear.

The user may open the "Read Me" file, or review the file at a later time.

10. Press the "Finish" button to complete the installation process.

4 GPS Antenna Specifications. The MIDG Series INS/GPS must be connected to an external GPS antenna for reception of GPS signals. The MIDG

Series INS/GPS can be use with active or passive GPS antennas. The SMA connector on the rear of the MIDG Series INS/GPS supplies +5 VDC to the user's GPS antenna.

4.1 Active GPS Antennas. For most applications an active GPS antenna is

Figure 8. Finished Installation Screen recommended. The antenna is powered through the SMA connector, which provides +5VDC on the center pin. Any antenna connected to a MIDG Series

INS/GPS must be designed for +5VDC operation, and must not draw more than

25 mill-amperes. When an active antenna is used, it should have a rated gain of at least 15 dB, with greater gains needed for longer cables or obstructed view of the sky. The maximum gain (only when long cables are involved) must not be greater than 50 dB and if a high gain antenna is used, the user must make sure the actual signal at the SMA connector is less than –61 dBm (e.g., by having

Figure 9. MIDG Series INS/GPS enough cable between the antenna and the MIDG Series INS/GPS to attenuate the antenna amplifier signal) in order to prevent swamping the GPS receiver and degrading the MIDG II performance. A typical useable antenna gain range is 15-30 dB.

Optional Patch Antenna A-GPS5-SMA

4.2 Passive GPS Antennas. If the cable length between the MIDG Series INS/GPS and the GPS antenna is short (less than

12 inches [300 mm]) and the antenna as a very clear view of the sky, a passive GPS antenna may be used.


Page 4 of 13

4.3 Installing and Using the MIDG Series INS/GPS Patch Antenna. The MIDG Series INS/GPS can be ordered with a patch antenna (Figure 9 - Microbotics Part Number A-GPS5-SMA). This antenna is designated for use with the MIDG Series

INS/GPS to provide GPS reception to the onboard receiver. The complete antenna specifications are included in Attachment

"D" of this manual.

1. Place the patch antenna in a location with an unobstructed view of the sky.

2. Connect the SMA connector from the antenna cable to the SMA jack on the face-plate of the MIDG

Series INS/GPS.

5 Installing and Using the SLC2JUSB Interface Cable. The MIDG Series

INS/GPS can be ordered with a SLC2JUSB interface cable. This cable is specifically designed to interface the MIDG Series INS/GPS with any PC or laptop via USB port. The SLC2JUSB cable (Figure 10) provides both power and data lines for the MIDG Series INS/GPS.

5.1 SLC2JUSB Driver Installation. The driver installation is an automated process once it is started and will require only minimal user action.

1. On the MIDG Software and Utilities CD-ROM, Select the driver file from the same folder from which the MIDG

Software and utilities was selected. (Figure 11). This is the appropriate drivers for the software installation.

Figure 10. SLC2JUSB Interface Cable

Figure 12 shows the command prompt window. After the drivers have been installed, the command prompt window will display, "FTDI CMD Driver Installation process

completed." The command prompt window will them close and the driver installation is complete.

5.1.1 Using the SLC2JUSB. After the drivers have been installed, whether automatically or manually, the following will instruct the user on how to interface the

MIDG Series INS/GPS with the PC or laptop.

1. Plug the USB end of the interface cable into any port on the PC

or laptop. The first time the interface cable is used, the PC or laptop will have to identify the device and then assign the drivers previously installed for it to operate correctly. Figure 13 shows the notification for when the SCL2JUSB is first interfaced.

2. Wait for the PC or laptop to finish

"installing" the new hardware. Once the

PC or laptop shows the notification that the hardware has been successfully installed, the cable is ready to be used (Figure 14).

Figure 11. MIDG Software and

Utilities CD-ROM folder containing SLC2JUSB Drivers.

Figure 12. MIDG II Display and Help Box


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3.

4.

Connect the MIDG Series INS/GPS to the SLC2JUSB

interface cable. Since the MIDG Series INS/GPS is powered by the USB port, no external power supply is required.

Start an instance of the MIDG Display Utility and under the "Port" drop down menu, select the COM Port Number

which is NOT native to the PC or laptop. The MIDG

Display Utilities should display the data outputted from the

MIDG. If there is no data being displayed, verify that the "Baud" rate on the MIDG Display Utilities program and the MIDG Series INS/GPS are the same.

Figure 13. Found New Hardware

Notification


5.2 Using the SLC2J09SF Interface Cable. The MIDG Series INS/GPS can be ordered with a SLC209SF interface cable.

This cable is specifically designed to interface the MIDG Series INS/GPS with any PC or laptop via serial port. Unlike the

SLC2JUSB, the SLC2J09SF interface cable (Figure 15) requires no driver installation. The SLC2J09SF provides both power and data lines for the MIDG Series INS/GPS; however, unlike the SLC2JUSB interface cable, the SLC2J09SF requires an external power supply to power the

MIDG Series INS/GPS. The external power supply must be able to provide, at a minimum 10 VDC and should not exceed 32 VDC (10 - 32VDC).

5.2.1 Connecting the SLC2J09SF Interface Cable. The following will instruct the user on how to interface the MIDG Series INS/GPS to a PC or laptop via the SLC209SF interface cable.

1.

Figure 15. SLC2J09SF MIDG Series

INS/GPS Interface Cable.

Verify that the external power supply is OFF. Connect the RED and BLACK "pig-tailed" wires on the SLC2J09SF interface cable to the external power supply.


Page 6 of 13

2.

3.

4.

Connect the SLC2J09SF interface cable to a PC serial port.

Connect the MIDG Series INS/GPS to the SLC2J09SF interface cable.

Start an instance of the MIDG Display Utility and under the "Port" drop down menu, select the

COM Port Number which the MIDG Series INS/GPS has been connecter to.

5. Apply power to the MIDG Series INS/GPS. The MIDG Display Utility program should immediately begin to give a data read out from the MIDG Series INS/GPS. If there is no data being displayed, verify that the "Baud" rate on the MIDG Display Utilities program and the MIDG Series INS/GPS are the same.

6 User Supplied Interface. Users may construct their own interface cable or permanently mount the MIDG Series INS/GPS with in an application. This section will instruct the user on how to wire the MIDG Series INS/GPS into an application. The

MIDG Series INS/GPS can easily be wired into a system using RS-422 signals, or it can be wired into a system with an RS-

422 to RS-232 serial voltage level converter (such as the Microbotics SLC10232). Table 1 provides full information about each pin and Figure 16 shows a visual representation of the Omnetics Mating connector.

Table 1: MIDG Series INS/GPS Pin-Out

Pin 1 R b

Pin 2 R a

Pin 3 PPS_N

Pin 4 PWR_IN

RS-422 positive data receipt into MIDG II (MARK High)

RS-422 negative data receipt into MIDG II (MARK Low)

1 pulse-per-second (1 PPS-Pulse: IDLE High, Falling Active Edge)

Power Input (10V to 32V input)

Pin 5 GND

Pin 6 T b

Pin 7 T a

RS-422 positive data transmit from MIDG II (MARK High)

RS-422 negative data transmit from MIDG II (MARK Low)

Pin 8 PPS_P/AUX 1 pulse-per second (1 PPS-Pulse: IDLE Low, Rising Active Edge)

Pin 9 PWR_RTN

Pin 10 SHIELD

Digital ground – tie to ground of user serial port

Power ground (negative side)

Shield for power cabling (if needed)

6.1 General Connections. There are four connections which are common to RS-422 and RS-232. The common connections are as follows:

A. Power In: Pin 4, Orange wire on the

Omnetics mating connector, 10-32 VDC input.

B.

C.

D.

Power Return: Pin 9, Gray wire on the

Omnetics mating connector, return.

Ground: Digital Ground, Yellow wire on the Omnetics mating connector, tied to the ground of the user serial port.

Shield: Pin 10, White wire on the Omnetics mating connector, tied to the shield of the user power cable

PERCEIVED LOOKING INTO THE FACE OF THE

CONNECTOR FOR THE MIDG SERIES INS/GPS

Pin 1 Black R b

Pin 2 Brown R a

Pin 3 Red PPS_N

Pin 4 Orange PWR_IN

Pin 5

Pin 6

Yellow

Green

Pin 7 Blue

Pin 8 Violet

GND

RS-422 (Receive Pos.)

RS-422 (Receive Neg.)

1 PPS-Idle High, Falling Active Edge

Power In (10 - 32 VDC)

Digital Ground

T b

RS-422 (Transmit Pos.)

T a

RS-422 (Transmit Neg.)

PPS_P/AUX* 1 PPS-Idle Low, Rising Active Edge *

Pin 9 Gray

Pin 10 White

PWR_RTN

SHIELD

Power Return

Shield

Note: Power Return and Shield are connected to Digital Ground.

*Trigger Input on Units with Trigger Option



Page 7 of 13

6.1.1 Power Connections. Steps one (1) and two (2) will instruct the user on the proper power input and power return connections. As stated in section 5.2, the MIDG Series INS/GPS requires a DC power source capable of a minimum of 10

VDC and not to exceed a maximum of 32 VDC (10-32 VDC). The unit uses a switch-mode power converter with a typical constant power dissipation of less than 1.2 watts.

1. Connect the positive side of the power source to the (Pin 4-Red).

2. Connect the negative side of the power source to the (Pin 9-Gray).

6.1.2 Digital Ground Connections. Steps three "a" (3a) and three "b" (3b) will instruct the user on the proper connections for the Digital Ground. Special attention should be applied while making this connection because of the specific configuration of the user's system.

3a. Connect the line (Pin 5-Yellow) to the Ground of the user system's RS-422 port. This line is tied directly to the Digital Ground user's serial port.

3b. Connect the line (Pin 5-Yellow) to the Ground of the user's RS-232 serial voltage level converter.

This line is tied to the user's Digital Ground on the RS-422 to RS-232 serial voltage level converter. The

Digital Ground from this converter should also be tied to the user's Digital Ground on the RS-232 port.

6.1.2 Shield Connections. Steps four (4) will instruct the user on the proper connections for the Shield line. (Optional)

4. Connect the Shield line to the shield of the power cable. (If applicable)

6.2 RS-422 Data Connections. The MIDG Series INS/GPS uses a RS-422 differential-mode asynchronous serial data stream for communications to and from the user's system. Figure 17 shows a typical RS-422 to RS-422 connection. As shown, there are five signal lines which are used for serial communications: , , , , and .

1.

2.

Connect the and pair (Pin 6-Green; Pin 7-Blue, respectively) to the and pair of the user's

system. The pin is connected to the pin of the user system. The pin is connected to the pin of the user system. The , and , pins are signals transmitted from the MIDG Series INS/GPS.

Connect the and pair (Pin 2-Brown; Pin 1-Black, respectively) to the and pair of the user's

system. The pin is connected to the pin of the user system. The pin is connected to the pin of the user system. The and pins are signals received by the MIDG Series INS/GPS.


Page 8 of 13

Figure 17. Typical RS-422 to RS-422 Data Connections

6.3 RS-232 Data Connections. The MIDG Series INS/GPS only supports RS-422 data communications. However, with a serial voltage level converter (such as the Microbotics SLC10232), the RS-422 data stream is easily converted into a RS-232 data stream. This enables the MIDG Series INS/GPS to communicate over an RS-232 port like those used on a PC or laptop computer. A typical connection to a PC-style serial port using the Microbotics SLC10232 Serial Voltage Level Converter is shown in Figure 18.

3.

4.

1.

2.

Connect the and pair (Pin 6-Green; Pin 7-Blue, respectively) to the and pair of the

SLC10232. The pin is connected to the pin of the user system. The pin is connected to the pin of the user system. The , and , pins are signals transmitted from the MIDG Series INS/GPS.

Connect the and pair (Pin 2-Brown; Pin 1-Black, respectively) to the and pair of the

SLC10232. The pin is connected to the pin of the user system. The pin is connected to the pin of the user system. The and pins are signals received by the MIDG Series INS/GPS.

Connect the of the SLC10232 to the

Data is transmitted from the MIDG via , and , pins to the SLC10232. The SLC10232 converts the signal from RS-422 to RS-232 and transmits the data to the PC's data in port via the line.

Connect the of the SLC10232 to the DATA OUT pin of the PC.

Data is transmitted to the SLC10232 via . The SLC10232 converts the signal from

RS-232 to RS-422 and transmits the data to the MIDG via , and , pins of the SLC10232.


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Figure 18. RS-422 to RS-232 serial voltage level converter connected between a MIDG Series INS/GPS and a PC

6.4 1 Pulse-per-Second Output. When the MIDG Series INS/GPS has a valid GPS input, the 1 Pulse-per-Second ( ) output is operational. This signal is derived from the data transmitted by the

GPS satellites and generates a 100 microsecond pulse once every second. There are two outputs available at the MIDG Series INS/GPS connector:

signal (Pin 3) is a 3 volt signal which remains (3 Volts) and pulses (0

Volts) for 100 microseconds.

B. The PPS_P signal (Pin 8) is a 0 volt which remains (0 Volts) and pulses

100 microseconds.

(3 Volts) for



Page 10 of 13

6.4.1 Trigger Input. The MIDG Series INS/GPS may be ordered with a "Trigger Input" option (Microbotics SIS90031C-

SR). This model in the MIDG Series INS/GPS has the output (Pin 8) replaced with the input. This specific modification allows the user to send a signal to the MIDG Series INS/GPS. Upon receiving this signal, the modified unit will record the GPS Time when this event occurred and then send an output data message informing the user of this event.

The signal for the (Pin 8) must present a rising edge ( transition). The input is TTL-compatible, 3V-

CMOS-compatible, and is 5V-tolerant. The input of this model of MIDG Series INS/GPS has a 4.7K pull-up resistor to 3V

input uses the signal line for and can be driven by a closure to or by an open-collector signal to . The ground return, and the line must be connected to the user system.

7 MIDG Series INS/GPS Dimensions and

Mounting. The MIDG Series INS/GPS has been mechanically designed to minimize both size and weight. This make the MIDG Series INS/GPS suitable for any application which size, weight, and power dissipation are key considerations.

7.1 Physical Dimensions. The MIDG Series

INS/GPS physical dimensions and standard reference axis of the are shown in Figure 20.

7.1.1 Physical Characteristics. The side of the

MIDG Series INS/GPS with the product label is considered the top, and the side with the connectors is considered the rear (the negative X axis). The MIDG Series INS/GPS was designed in order to maintain directional consistency with the Navigation Industry, the positive Y axis is to the right of the unit, and the positive Z axis is downwards. This axes orientation sets the standard positive roll rotation as right-side-down, the positive pitch rotation as front-end-up, and the standard positive yaw rotation as clockwise viewed from the top.

7.2 Mounting the MIDG Series INS/GPS. The

MIDG Series INS/GPS allows the user several option for mounting the unit within an application. The unit can be hard mounted or soft mounted and can be mounted in any orientation.

7.2.1 Hard mounting the MIDG Series

INS/GPS. The MIDG Series INS/GPS has four 0-

Figure 20. MIDG Series INS/GPS Mechanical Dimensions

80 threaded holes for hard mounting of the unit. If the unit is to be hard mounted into and application, the maximum depth of screw insertion is .187” (4.75 mm). Furthermore, if the unit is to be hard mounted, the unit must be arranged to be isolated from vehicle vibrations and shock.


Page 11 of 13

7.2.2 Soft Mounting the MIDG Series INS/GPS. Due to the small size and light weight of the MIDG Series INS/GPS, in most applications, the unit can be mounted via the use of 1/8” double-sided foam tape. This type of mounting not only helps to reduce vibration from coupling into unit, but also makes removal of the unit from an application easier.

7.3 Mounting Orientation. The MIDG Series INS/GPS can be mounted in any orientation within an application. However, for optimal performance, the

MIDG Series INS/GPS should be mounted as closely to the center as possible and with the same orientation as the application (i.e. the front of the unit pointed in the same direction as the front of the application). Figure 21 shows the three axes of the MIDG Series INS/GPS for aiding in proper mounting of the unit.


Axes

7.3.1 Orientation Correction. In applications where the MIDG Series INS/GPS cannot be mounted optimally, MIDG Series

INS/GPS can be aligned to any orientation. The by using the "Transform" (Xform) function, the MIDG Series INS/GPS may be oriented into a perfect alignment within an application.

8 MIDG Series INS/GPS Messages. The MIDG Series INS/GPS sends message via an asynchronous serial port using RS-422 voltage levels.

This type of communication makes the MIDG Series INS/GPS suitable for use in electrically noisy environments. The data is binary-encoded as eight data bits, no parity, and one stop bit (“8, N, 1”) with no data flow

Table 2: MIDG Series INS/GPS Baud Rates

115200

57600

38400 control. The default baud rate is set at 115200 Baud; however, the user can change the baud rate by using the MIDG Display Utility software or by sending the appropriate BAUD Configuration Message to the unit.

19200

9600

Table 2 shows the baud rates supported by the MIDG Series INS/GPS.

8.1 Microbotics Binary Protocol. The MIDG Series INS/GPS uses the standard Microbotics Binary Protocol. All of the

MIDG Series INS/GPS messages are based on the Microbotics binary protocol; an ASCII data terminal program (i.e.

Microsoft® Hyper-Terminal) cannot read nor be used to communicate with a MIDG Series INS/GPS. Refer to Attachment

"B" for a complete MIDG Series INS/GPS Message Specification

8.1.1 Microbotics Binary Protocol Message Contents. Microbotics binary protocol is a serial data stream comprised of 8bit bytes with the following basic format:

A B C D E


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A.

B.

C.

Sync0 and Sync1: The Sync0 and Sync1 bytes are used to indicate the beginning of a specific message and have the binary values of 0x81 and 0xA1, respectively.

Packet_ID: The Packet_ID is an unsigned 8-bit byte identifying the command type.

Payload_count: The Payload_count is an unsigned 8-bit byte indicating the number of bytes in the payload to follow. The Payload_count can be 0x00 (no payload) through 0xFF (255 theoretic maximum

bytes in the actual payload).

D. Payload: The payload is specific for the message is specified in the . The payload can be comprised of any mix of bytes, 16-bit words, or 32-bit words. All Payload values are sent in big-endian format – the first byte of each multi-byte value (16-bit or 32-bit data values) contains the most significant bits of that value.

E. CS0 and CS1: The CS0 and CS1 part of the message forms a two-byte Fletcher checksum. This checksum includes of all bytes between Sync1 and CS0.

8.1.2 Fletcher Checksum. The Microbotics Message Specification uses a Fletcher checksum regardless of the message type and payload. The Fletcher checksum is calculated in the following manner:

1.

2.

3.

4.

5.

9 Help and Support. Microbotics, Inc. is dedicated to supporting the missions of our clients and offers free thirty (30) days of support for all of our products. The MIDG Display utility, in the "Help" drop-down menu, contains the contact information for Microbotics, Inc (Figure 22).

1. Start an instance of the MIDG Display Utility.

2. Select the Help drop-down menu.

2. Select the "About" option.

Figure 22. MIDG Display Utility "About" information Box.

Visit Microbotics on our website at www.microboticsinc.com

for more information about our entire product line. For pricing and availability, please visit our contact page at www.microboticsinc.com/contact.html

. All technical inquires should be sent to [email protected]


Page 13 of 13

Attachment A

SLC2JUSB

1 Introduction. The SLC2JUSB interface cable (MBI# - SLC2JUSB) is designed to take advantage of a computer's USB port to provide the MIDG Series INS/GPS with bidirectional communication and power (Figure 1).

1.1. Description. The MIDG II INS USB Interface Cable is approximately forty-eight inches (48 in/121.92 cm) in length and covered with black plastic sheathing. At one end of the cable is a standard Type A male USB connector which will connect to any Type

A female USB receptacle on the user's computer The other end of the cable has an

Omnetics 10 pin mating connector specifically designed to connect to any MIDG Series

INS/GPS unit.

Figure 1. SLC2JUSB

1.2. Functionality. The SLC2JUSB interface cable is designed to power a MIDG

Series INS/GPS unit via USB port. Therefore, there is no requirement for an external power supply. The interface cable has a recessed "reset" button on the top of the USB connector housing (Figure 2 - Circled in Red) which provide the user with the ability to cycle the power to the MIDG Series INS/GPS without having to unplug the unit or the cable.

Figure 2. Recessed Power Button.

2 Installation. The SLC2JUSB interface cable may be ordered with a MIDG Series

INS/GPS or it may be ordered separately. In both cases, a CD-ROM will arrive with the interface cable containing the drivers. These drivers will have to be installed prior to using the interface cable.

2.1 SLC2JUSB Driver Installation. It is advised that all users install the drivers provided with the SLC2JUSB interface cable; however, depending on the specific version of the Windows®, the operating system may automatically search for and install the drivers. The driver installation is an automated process once it is started and requires only minimal user action.

1. On the MIDG Software and Utilities CD-ROM, Select the driver file from the same folder from which the MIDG Software and

utilities was selected. (Figure 3). This is the appropriate drivers for the software installation.

Figure 4 shows the command prompt window. After the driver installation has been completed, the command prompt

Figure 3. MIDG Software and

Utilities CD-ROM folder containing SLC2JUSB Drivers. window will display, "FTDI CMD Driver Installation

process completed." and will close. The driver installation is complete.

2.2 Windows® 7. The Windows® 7 operating system will automatically install the drivers as soon as the cable is plugged into a USB port. Figure 5 shows the notifications of the driver installation after the SLC2JUSB is plugged into a

USB port.

Figure 5. Windows® 7 automatically installing FTDI

Drivers for the SLC2JUSB Interface Cable.



Page A1 of A3

3 Using the SLC2JUSB. After the drivers have been installed, whether automatically or manually, the following will instruct the user on how to interface the MIDG Series INS/GPS with the PC or laptop.

1. Plug the USB end of the interface cable in any USB port on

the PC or laptop. The first time the interface cable is used, the

PC or laptop will have to identify the device and then assign the drivers previously installed for it to operate correctly.

Figure 6 shows the notification for when the SCL2JUSB is first interfaced with the computer.

Figure 6. Found New Hardware

Notification

2. Wait for the PC or laptop to finish "installing"

the new hardware. Once the PC or laptop shows the notification that the hardware has been successfully installed, the cable is ready to be used (Figure 7).

Figure 7. New Hardware is Ready to Use

Notification

3.

4.

Connect the MIDG Series INS/GPS to the SLC2JUSB interface cable. Since the MIDG Series

INS/GPS is powered by the USB port, no external power supply is required.

Start an instance of the MIDG Display Utility and under the "Port" drop down menu, select the

COM Port Number which is NOT native to the PC or laptop. The MIDG Display Utilities should display the data outputted from the MIDG. If there is no data being displayed, verify that the "Baud" rate on the MIDG Display Utilities program and the MIDG Series INS/GPS are the same.

5 Assigning COM Port Numbers. Due to user variations in the setup of their PC's or laptops, it is impossible to assign a standard COM port number for the

SLC2JUSB interface cable. The current drivers are set to have the interface cable assigned o the first available COM port. Unfortunately, the MIDG Display Utility only supports nine (9) active COM ports (i.e. COM 1 through COM 9) this section will guide the user through the process of reassigning COM port numbers.

5.1 Accessing the Device Manager. The following steps are the instructions for opening the "Device Manager" in Windows® 2000 through Windows® XP-64.

1. Pressing the Windows key and the Pause key at the same time to open the "System Properties" dialog box

2. Select the "Hardware" tab in the "System Properties" dialog box (Figure 8). Figure 8. System Properties dialog box, Hardware Tab


Page A2 of A3

3.

4.

5.

Select the "Hardware" tab in the "System

Properties" dialog box (Figure 8).

Press the "Device Manager" button to open the "Device Manager" (Figure 9).

Double click on the "USB Serial Port"

listing. This will open the "USB Serial Port

(COM 15) Properties" dialog box (Figure 10).

Figure 9. Device Manager with "Ports (COM&LPT)" expanded.

Figure 10. Port Settings Tab of the "USB Serial Port Properties" dialog box.

10.

6.

7.

8.

9.

Select the "Port Settings" Tab. This will display the port settings

(Figure 10).

Press the "Advanced..." button. This will open the "Advanced

Settings for the COM port.





Select the "COM Port Number" drop down menu and choose a COM Port which is not being used AND lower than COM

Port 10. This will open the "Advanced

Settings for the COM port (Figure 11).

11.

12.

Select the "OK" to complete the

reassignment. This will reassign the COM port to the number which was designated.

After the COM port has been successfully

reassigned, close all system windows.

Figure 11. Advanced COM Port Settings.

6 Help and Support. Microbotics, Inc. is dedicated to supporting the missions of our clients and offers free thirty (30) days of support for all of our products.

Visit Microbotics on our website at www.microboticsinc.com

for more information about our entire product line. For pricing and availability, please visit our contact page at www.microboticsinc.com/contact.html

. All technical inquires should be sent to [email protected]


Page A3 of A3

MIDG IIC Message Specification for Firmware V2.1.x and Higher

9 January 2012

1 Scope. This document outlines the messages sent to and from the MIDG IIC via the serial communications port.

1.1 Differences Between This Message Specification and Previous Versions. This specification is an update to earlier Message Specifications. In particular, it addresses certain messages which are no longer supported (especially by firmware versions 2.3.1 and higher), corrects several errors, and better defines the Configuration Messages.

Of particular importance are several data packets which are either no longer properly supported by the GPS module in the MIDG IIC, no longer of valid use to the client, or provide possible false information, thus the related messages should not be used in firmware versions below 2.3.x, and are no longer supported in firmware versions 2.3.1 and higher:

Satellite Ephemeris (TIM_EPH Message)

GPS Raw Data (GPS_RAW Message)

GPS 1PPS Estimate (GPS_PPS Message)

Time Error (TIM_ERR Message)

RTCM Differential Corrections (RTCM Message)

Additionally, the various “ VG ” Modes previously used in earlier versions are now referred by their actual operations (STATUS Message).

2 Serial Interface. Communication with the MIDG IIC occurs via an asynchronous communication port using the Microbotics Binary Interface Protocol (MBI). The

Factory default is 115200 Baud, 8 data bits, no parity bit, and one stop bit (8, N, 1). The baud rate can be changed by the user via the MIDG Display/Configuration Program.

The physical interface is an RS-422 differential serial link for high noise immunity.

3 Microbotics Binary Protocol. The MBI Protocol is a series of message packets, defined in the following sections, to communication with the host computer. These

CHECKSUM RANGE

SYNC_0

Hex: 0x81

Dec: 129

SYNC_1

Hex: 0xA1

Dec: 161

ID COUNT PAYLOAD_1 PAYLOAD_N CHKSUM_0 CHKSUM_1 messages provide sensor data transfer between MIDG IIC the host, as well as facilitate MIDG IIC configuration. The MBI Protocol is a standardized binary byte packet format that has the following structure:

3.1 SYNC Bytes. The two SYNC bytes are used to define the message packet. The first byte (SYNC_0) is has the hexadecimal value of 0x81, while the second byte (SYNC_1) has the hexadecimal value of 0xA1.

3.2 ID Byte. The ID byte defines the specific message.

3.3 COUNT Byte. The COUNT byte is the number of bytes in the payload regardless of payload formatting, zero if the message has no payload bytes.

3.4 PAYLOAD. The payload is composed of a sequence of bytes that represent data values within a message. All payload values are bit-endian, meaning the most significant byte of a multi-byte payload value is sent first. In bit field values, Bit 0 represents the least significant bit of the payload value. In the section that follows, the application messages will be defined using the nomenclature shown below to indicate the type of value represented in the payload.

Payload Type

U1

U2

U4

Bx

BN

Description

Unsigned, 8 bit integer (one byte)

Unsigned, 16 bit integer (two bytes)

Unsigned, 32 bit integer (four bytes)

String of x bytes (x bytes)

Variable length string of bytes

Payload Type

I1

I2

I4

R4

R8

Description

Signed, 8 bit integer (one byte)

Signed, 16 bit integer (two bytes)

Signed, 32 bit integer (four bytes)

IEEE 754 single precision (four bytes)

IEEE 754 double precision (eight bytes)

3.5 CHECKSUM Bytes. The two-byte checksum is a Fletcher checksum as defined in internet RFC 1145. It is computed over all bytes between, and including, the ID byte,

COUNT byte, and all payload bytes. The basic algorithm is as follows:

CHKSUM_0 = 0

CHKSUM_1 = 0 for each byte from ID to PAYLOAD_N (inclusive)

CHKSUM_0 = CHKSUM_0 + byte Only 8 bits maintained (modulo-256)

CHKSUM_1 = CHKSUM_1 + CHKSUM_0 Only 8 bits maintained (modulo-256)

Once the checksum has been calculated, the low 8 bits of CHKSUM_0 are send, followed by the low 8 bits of CHKSUM_1.

MIDG IIC Message Specification, Firmware 2.1 and above (9 January 2012) Page B1 of B27

4 MIDG IIC Output Messages. The following messages are provide data output from the MIDG IIC. Any of these messages may be configured to be transmitted from the MIDG IIC at a user selectable rate from once every 5 seconds to 50Hz. Rates for these messages are set using the CFG_SET Message (ID 35) with the MSG_DIV Command

(ITEM_ID 5). When a message is disabled (its output rate is set to zero), it may be polled by sending a message of the same ID to the MIDG IIC, but with no payload (the message payload length COUNT zero). Supported MIDG IIC output messages:

ID 1 STATUS MIDG IIC Status

ID 2 IMU_DATA IMU Data

ID 3 IMU_MAG Magnetometer Data

ID 10 NAV_SENSOR Navigation Sensor and Attitude Data

ID 12 NAV_PV Navigation Position/Velocity Data

ID 13 NAV_HDG Navigation Heading Data

ID 15 NAV_ACC Navigation Accuracy Estimate

ID 20 GPS_PV GPS Position/Velocity Data

ID 21 GPS_SVI GPS Satellite Vehicle Data

¶

ID 22 GPS_RAW GPS Raw Measurement Data

ID 23 GPS_CLK GPS Clock Data

¶

ID 24 GPS_EPH Ephemeris Data (polled only)

ID 25 TIM_UTC UTC Time

∗

∗

ID 26 TIM_ERR Time Error

ID 27 TIM_PPS Time at 1 PPS

§

ID 28 TIM_TM Time at Time Mark pulse in

¶

Due to undocumented changes in GPS modules by the manufacturer, not all MIDG IIC units support the GPS_RAW or GPS_EPH Messages correctly. As it is impossible to determine in the field if the messages are available and valid, these messages should not be used in firmware versions below 2.3.x. These messages are not available in firmware versions 2.3.1 and higher.

∗

The TIM_ERR Message is a legacy message from the earliest MIDG-Series units, and provides no data useable to the user. This message is not available in firmware versions 2.3.1 and higher. TIM_PPS Message is a legacy message from when the MIDG-Series did not have 1PPS Time Pulse outputs. As communications latencies can cause errors, this message should not be used for estimating the Time Pulse timing. This message is not available in firmware versions 2.3.1 and higher.

§

The TIM_TM Message is available only in MIDG IIC units with the Time Mark Option (Microbotics Part Number SIS90031C-SR).


4.1 Message: STATUS Message

Description: Status Information

Payload Contents

Byte Number Units Purpose / Comment

Payload Length:

Applicable Modes:

0

4

U4

U2 msec

Bit field

6 I2

Notes:

(1)

Operational mode definitions:

0.01 °C

Current Designation Previously Called

IMU Mode

Initialize Alignment

Coarse Alignment

Medium Alignment

Fine Alignment

Vertical Gyro Mode

INS Mode

IMU Mode

VG Init

VG Fast

VG Medium

VG Slow

VG SE

INS Mode

8 Bytes (0x08)

IMU, VG, INS

Timestamp

System Status:

Bits 8..15:

Bit

Bit

Bit

Bit

7:

6:

5:

4:

Bits 3..0:

(N/A, read zero)

NV Configuration Valid

Timestamp is GPS time

DGPS (SBAS – WAAS, EGNOS, MSAS)

(N/A, reads zero)

Current operational mode:

(1)

1

2

3 = Coarse Alignment

4

5 = Fine Alignment

6 = Vertical Gyro Mode

7 = INS Mode

Internal Temperature

Defiinition

IMU operational mode: only sensor data available, Kalman Filter not active

Sensor alignment initialization

Sensor coarse alignment

Sensor medium alignment

Sensor fine alignment

Vertical Gyro operational mode: all data available, Kalman Filter active without using GPS data

INS operational mode: all data available, Kalman Filter active using GPS data


4.2 Message: Message

Description: Inertial Measurements



Payload Length:

Applicable Modes:

23 Bytes (0x17)

IMU, VG, INS

0 U4 msec Timestamp

4

6

8

I2

I2

I2

.01 °/s

.01 °/s

.01 °/s

X-Axis Angular Rate

(1)

Y-Axis Angular Rate

Z-Axis Angular Rate

10

12

14

I2

I2

I2 milli-g milli-g milli-g

X-Axis Acceleration

(1,2)

Y-Axis Acceleration

Z-Axis Acceleration

16

18

20

I2

I2

I2

Relative units

Relative units

Relative units

X-Axis Magnetic Field

(3)

Y-Axis Magnetic Field

Z-Axis Magnetic Field

22 U1 Bit field Flags:

Bit

Bit

7:

6:

Bits 5..0:

Notes:

(1)

The sensor readings are calibrated values not compensated by the Kalman Filter.

GPS 1PPS flag


(N/A, read zero)

(2)

“1 g” is defined as 9.799096177 m/sec

2

.

(3)

The magnetometer outputs are scaled so that the magnitude of the local field at MIDG IIC calibration is 5000 counts.


Description: Magnetometer Measurements



Payload Length: 11 Bytes (0x0B)

Applicable Modes: IMU, VG, INS

0 U4 msec Timestamp

4

6

8

I2

I2

I2

Relative units X-Axis Magnetic Field

(1)

Relative units Y-Axis Magnetic Field

Relative units Z-Axis Magnetic Field


Bit 7:

Bit 6:

Bits 5..0:

(N/A, reads zero)


(N/A, read zero)

Notes:

(1)

The magnetometer outputs are scaled so that the magnitude of the local field at MIDG IIC calibration is 5000 counts.


4.4 Message: Message Payload Length: 39 Bytes (0x27)

Byte Number Units


Purpose / Comment

0 U4 msec Timestamp

4

6

8

I2

I2

I2

.01 °/s

.01 °/s

.01 °/s

X-Axis Angular Rate

(1)

Y-Axis Angular Rate

Z-Axis Angular Rate

10

12

14

I2

I2

I2 milli-g milli-g milli-g

X-Axis Acceleration

(1,2)

Y-Axis Acceleration

Z-Axis Acceleration

16

18

20

I2

I2

I2

0.01deg

0.01deg

0.01deg

Yaw, Local Frame Z-Axis Attitude

(3)

Pitch, Local Frame Y-Axis Attitude

Roll, Local Frame X-Axis Attitiude

22

26

30

34

I4

I4

I4

I4

2

-30

-

30

2

2

2

-30

-30

Orientation Qw

(4)

Orientation Qx

Orientation Qy

Orientation Qz

38 U1 Bit field

Notes:

(1)

The sensor readings are compensated by the Kalman Filter.

Flags:

7:

6:

DGPS

4:

Bit

Bit

Bit

Bit

3: External heading measurement applied

2: External position measurement applied

(5)

1: External velocity measurement applied

0: External air data measurement applied

(5)

(2)

“1 g” is defined as 9.799096177 m/sec

2

.

(3)

Rotation sequence is taken Yaw, Pitch, Roll.

(4)

The elements of the Orientation Quaternion must be multiplied by 2

-30

(9.31322574615 x 10

-10

) to get a unit quaternion.

(5)

External Position and External Air Data aiding have not been implemented, bits read zero.


Message

Description: Navigation Position and Velocity Solution



Payload Length: 29 Bytes (0x1D)

Applicable Modes: VG, INS

0

4

8

12

16

20

24

28

U4

I4

I4

I4

I4

I4

I4

U1 msec cm, 10

-7 cm, 10

-7

deg

deg cm cm/s cm/s cm/s

Bit field

Timestamp

X-Axis Position (ECEF X, Relative Position East, or Longitude)

(1)

Y-Axis Position (ECEF Y, Relative Position North, or Latitude)

Z-Axis Position (ECEF Z, Relative Position Up, or Altitude)

X-Axis Velocity (ECEF Vx, or Relative Veast)

(2)

Y-Axis Velocity (ECEF Vy, or Relative Vnorth)

Z-Axis Velocity (ECEF Vz, or Relative Vup)

Solution Details:

Bit 7:

Bit

Bit

6:

5:

Bit 4:

Bits 3..2:

Position estimate invalid



Velocity estimate invalid

Position Format

0 = ECEF

1 = ENU Relative

(3)

2,3 = LLA

Bit 0:

ENU

ENU position relative to first fix

(3)

Notes:

(1)

Position format: ECEF or ENU Relative in cm; Longitude and Latitude in 10

-7

deg, Altitude in cm.

(2)

Velocity Format is either ECEF or ENU.

(3)

If Position Format is ENU Relative, position is relative to either the first GPS fix or location specified in configuration.


Message

Description: Navigation Heading Information



Payload Length: 17 Bytes (0x11)

Applicable Modes: INS

0 U4 msec Timestamp

4 I2 0.01 deg Magnetic Heading

6

8

I2

I2

0.01 deg

0.01 deg

Magnetic Declination

(1)

Magnetic Dip

10

12

14

I2

U2

I2

0.01 deg cm/s cm/s

Course Over Ground

Speed Over Ground

Vertical Velocity

(2)


Bit

Bit

7:

6:

Bits 5..0:

Declination and dip valid


(N/A, read zero)

Notes:

(1)

Magnetic Declination and Magnetic Dip are taken from the World Magnetic Model, which requires initialization with the current location. As a result, these values are not

valid until position is known and Bit 7 is set in the Flags bit field.

(2)

Course Over Ground, Speed Over Ground, and Vertical Velocity are calculated from the navigation solution data and correspond to the velocities presented in the NAV_PV

message.


Description: Navigation Solution Accuracy Estimate





0

4

6

8

10

12

14

16

U4

U2

U2

U2

U2

U2

U2

U1 msec cm cm cm/s cm/s

0.01 deg

0.01 deg

Bit field

Notes:

(1)

Values represents the probable standard deviation of error.

Timestamp

Horizontal position accuracy estimate

(1)

Vertical position accuracy estimate

Horizontal velocity accuracy estimate

(1)

Vertical velocity accuracy estimate

Tilt accuracy estimate

(1)

Heading accuracy estimate

Flags:

Bit

Bit valid

6:

5:

Bits 4..0:



(N/A, read zero)


GPS_PV

(1)

Message Payload

Description: GPS Position and Velocity Solution Applicable Modes: IMU, VG, INS




0

4

U4

U2 msec

Count

GPS Time

GPS week

6 U2 Bit field Solution Details:

Bits 15..12: Number of satellites used in solution

Bits 11..8: GPS Fix Type:

0 = No Fix

1 = Dead reckoning only

Bit 7:

2 = 2D Fix

3 = 3D Fix

4 = GPS + dead reckoning combined

Time of week valid

Bit

Bit

Bit

6:

5:

4:

Bits 3..2:

Week number valid

Differential solution (WAAS, EGNOS, MSAS)

GPS Fix valid

Position Format:

0 = ECEF

1 = ENU Relative

(2)

Bit

Bit

1: Velocity Format:

0 = ECEF

1 = ENU

0: ENU Relative Position relative to first fix

8

12

16

I4

I4

I4 cm, 10

-7 cm, 10

-7

deg

deg cm

X Axis Position (ECEF X, Relative East, or Longitude)

(3)

Y Axis Position (ECEF Y, Relative North, or Latitude)

Z Axis Position (ECEF Z, Relative Up, or Altitude)

20

24

28

I4

I4

I4 cm/s cm/s cm/s

X Axis Velocity (ECEF Vx, or Relative Veast)

32 U2 0.01 Position DOP

34

36

U2

U2 cm cm/s

Position Accuracy

(5)

Speed Accuracy

Notes:

(1)

This message is provided at the selected rate only if data is produced by the GPS receiver.

Y Axis Velocity (ECEF Vy, or Relative Vnorth)

Z Axis Velocity (ECEF Vz, or Relative Vup)

(4)

(2)

If Position Format is ENU Relative, position is relative to either the first GPS fix or location specified in configuration.

(3)

Position Format: ECEF or ENU Relative in cm; Longitude and Latitude in 10

-7

deg, Altitude in cm.

(4)

Velocity Format is either ECEF or ENU.

(5)

Accuracy is the square root of the variance in the filtered estimate.


GPS_SVI

(1)

Message

Description: GPS Satellite Vehicle Information

Payload Length: (8 * NCh) + 6 Bytes


(2)




0 U4 msec GPS Time

4 U1 (Reserved, value indeterminate)

5 U1 Count Number of satellites to follow (1..16)

After the 6 bytes above are sent, the following block is repeated NCh times (once for each satellite, 8 bytes per block)

(3)

:

(8 * N i

) + 6

(8 * N i

) + 7

U1

U1

Count

Address

Receiver channel number (1..16)

Satellite ID on this receiver channel

(8 * N i

) + 8 U1 dB

Hz

Carrier to Noise ratio

(8 * N i

) + 9 U1 Bit field Information regarding the satellite:

Bits 7..5: (N/A, value indeterminate)

Bit

Bit

4:

3:

Satellite is unhealthy, will not be used

Orbit information is ephemeris

Bit

Bit

Bit

2:

1:

0:

Orbit information available for this satellite

DGPS data available for this satellite

Satellite used for navigation

(8 * N i

) + 10 I1 Value Information regarding the receiver channel:

7: Code/carrier locked, receiving 50bps data

5,6:

4:

Code and carrier locked

Code locked

3:

1,2:

0:

Signal detected but unusable

Channel is searching

Channel is idle

(8 * N i

) + 11

(8 * N i

) + 12

I1 deg

I2 deg

Satellite Elevation

Notes:

(1)

This message is provided at the selected rate only if data is produced by the GPS receiver. The values in this message are data provided directly by the GPS module and passed to the output message without any intervening processing.

(2)

“NCh” is number of receiver channels in this message.

(3)

“N i

” goes from zero to (NCh - 1).


4.10 Message: GPS_RAW

(1,2)

Message

Description: GPS Raw Measurement Data



Payload Length: (24 * nSVs) + 8 Bytes

(3)


0

4

U4

U2 msec

Count

GPS Time

GPS week


7 U1 Count Number of satellites to follow (up to 10)

After the 8 bytes above are sent, the following block is repeated nSVs times (once for each satellite, 24 bytes per block)

(4)

:

(24 * N i

) + 8 R8 cycles

(24 * N i

) + 16 R8 m Pseudo Range

(24* N i

) + 24 R4 Hz

(24* N i

) + 28 U1 Address ID

(24* N i

) + 29 I1 Value Information regarding the receiver channel:

7: Code/carrier locked, receiving 50bps data

5,6:

4:

Code and carrier locked

Code locked

3:

1,2:

0:

Signal detected but unusable

Channel is searching

Channel is idle

(24 * N i

) + 30 U1 dB

Hz

Carrier to Noise ratio

(24 * N i

) + 31 U1 Loss of link indicator (RINEX definition)

Notes:

(1)

Due to undocumented changes in GPS modules by the manufacturer, not all MIDG IIC units support the GPS_RAW Message. As it is impossible to determine in the field if the Raw Data are available from the GPS module, this message should not be used.

The values in this message are data provided directly by the GPS module and passed to the output message without any intervening processing.

(2)

This message is provided at the selected rate only if data is produced by the GPS receiver.

(3)

“nSVs” is number of satellites in this message.

(4)

“N i

” goes from zero to (nSVs - 1).

4.11 Message: GPS_CLK

(1)

Message

Description: GPS Receiver Clock Solution





0 U4 msec GPS Time

4

8

I4

I4 ns ns/s

Clock bias

Clock drift

12

16

U4

U4 ns ps/s

Time accuracy estimate

Frequency accuracy estimate

Notes:

(1)



4.12 Message: GPS_EPH

(1,2)

Message

Description: GPS Satellite Ephemeris Data


Payload Length: 77 Bytes (0x4D)

(3)


Byte

Offset

Number

Format

Units Purpose / Comment

0 U1 Address Satellite ID

(3)

1 U4 GPS Handover word

After the 5 bytes above are sent, the following element is repeated 24 times. Each element is a 24-bit word of the GPS Navigation Message (see ICD-GPS-200). The 8 words following the Telemetry and Handover Words of Sub-frames 1 through 3 are included. Each word is arranged most significant byte first (big-endian):

5 + (N i

* 3) U3 24-Bit Word Navigation Words from Sub-frames 1 through 3

(4,5)

Notes:

(1)

Due to undocumented changes in GPS modules by the manufacturer, not all MIDG IIC units support the GPS_EPH Message correctly (the Navigation Words contents may be invalid). As it is impossible to determine in the field if the Ephemeris Data are available from the GPS module or if the message contents are valid, this message should not be used in firmware versions below 2.3.x. This message is not available in firmware versions 2.3.1 and higher.

(2)

This message does not have a configurable message rate. Ephemeris data is polled for a satellite by sending a message to the MIDG IIC with ID = 24 (GPS_EPH) and a single payload byte which is the Satellite ID for the satellite for which ephemeris data is being requested. In order to prevent overrunning the MIDG IIC output queue,

requests are cached and ephemeris messages are sent at a rate of only one ephemeris message per second.

(3)

If no valid ephemeris data is available for a satellite, this message will have a single byte payload, the Satellite ID, and the Handover Word and Navigation Words will not be

included. In this case, the Payload Length will be 1.

(4)

“N i

” goes from zero to 23.

(5)

Each these elements are 24-bit (3-byte) words. Since the Navigation Words require significant byte splitting and parsing, no effort is made to align the 24-bit words on 4- byte boundaries.

4.13 Message: TIM_UTC

(1)

Description: UTC Time

Message





0

4

U4

I4 msec ns

GPS Time

Nanoseconds of Second (-5 x 10

8

to +5 x 10

8

, UTC)

8

10

11

12

13

14

U2

U1

U1

U1

U1

U1

Value

Value

Value

Value

Value

Value

Year (1999..2099, UTC)

Month (1..12, UTC)

Day of Month (1..31, UTC)

Hour of Day (0..23, UTC)

Minute of Hour (0..59, UTC)

Second of Minute (0..59, UTC)

15 U1 Bit field Time information validity:

Bits 7..3: (Reserved, value indeterminate)

Bit

Bit

Bit

2:

1:

0:

Valid UTC (leap seconds known)

Week number valid

Time of week valid

Notes:

(1)



4.14 Message: TIM_ERR

(1)

Message

Description: Time Error Information





0

4

5

6

U4

I1

I1

U1 msec

Counts

Counts

Bit field

GPS Time

Time timer bias

Data timer bias

Flags:

Bit 7:

Bit 6:

Bits 5..0:

(N/A, reads, zero)


(N/A, read zero)

Notes:

(1)

This message is a legacy message that actually provides no useful data to the user as the message only defines information used internally by the MIDG-Series units.

This message is not available in firmware versions 2.3.1 and higher.

4.15 Message: TIM_PPS

(1,2)

Description: Time Pulse Information

27 (0x1B) Payload Length: 16 Bytes (0x10)




0

4

U4

U4 msec msec / 2

32

GPS time of next pulse

Fractional millisecond of next pulse

8 I4 ps Quantization error of next pulse

(3)

12 U2 GPS week number of next pulse


Bits 7..3: (N/A, read zero)

1:

Bit 0: Time base is (0=GPS, 1=UTC)


Notes:

(1)

This message is a legacy from when the MIDG-Series units did not have a Time Pulse output signal (1PPS), and indicates the estimated time of the next GPS time pulse.

This message is just passed through from the GPS module by the MIDG IIC, via two serial data transmissions with uncertain latencies. Thus the data in this message may be incorrect for the next pulse being output by the GPS module. As the 1PPS Time Pulse output signal is available at the MIDG IIC output connector, use of this message is not recommended. This message is not available in firmware versions 2.3.1 and higher.

(2)

The Time Pulse output signal is present only when the receiver is able to calculate a position solution. Accuracy of the Time Pulse output signal available at the MIDG

IIC output connector is 50 ns rms

, with 99% < 100 ns error.

(3)

The time pulse signal is aligned to a 23.104 MHz clock, which results in a resolution of 43 ns. The resulting quantization is considered in the time accuracy estimation of the receiver.


4.16 Message: TIM_TM

(1)

Message

Description: Time Mark Information





0

4

U4

U2 msec

Count

GPS time of received pulse rising edge

GPS week number of received pulse rising edge


Notes:

(1)

This message is only available on MIDG IIC units that have the Time Mark Option (Microbotics Part Number SIS90031C-SR) supporting an external pulse input at

Pin 8 of the MIDG IIC output connector. The MIDG IIC records the GPS time of the rising edge of the received pulse (+/- 1 ms), and sends this message at the first

50 Hz update slot of MIDG IIC processing (maximum update of 50 Hz). If multiple pulses are received in a 50 Hz period, only the time of the most recent rising edge

is reported.


5 MIDG IIC External Aiding Input Messages. The MIDG IIC messages defined in this section provide a mechanism for aiding the MIDG IIC Kalman filter with external measurements, including heading, magnetic vector, position, velocity, and air data. The MIDG IIC supports the following input aiding messages:

ID 31 HDG_MEAS Heading Aiding

ID 32 AID_MAG Magnetometer Vector Aiding

§

ID 37 AID_POS Position Aiding

ID 38 AID_VEL Velocity Aiding

§

ID 39 AID_AIR Airspeed Aiding

§

The AID_POS and AID_AIR Messages have not yet been implemented and are non-functioning. While the HDG_MEAS, AID_MAG, and AID_VEL Messages have been implemented, they have not been fully tested, nor are their effects, especially with invalid entries, fully known at this time. The user accepts any and all risks and consequences when using any aiding message.


Description: Heading Measurements


Applicable INS



0 U4 msec Time

(1)

4 U2 Bit fields

0.1 deg

Details and vertical position standard deviation:

Bit 15: Time value format

(1)

1 = GPS Time

Bits 14..12: (Reserved, send as zero)

Bits 11..0: Heading Standard Deviation

(2)

6 I2 0.1 deg Heading Measurement. Valid range is -1800 to +3600

(3)

Notes:

(1)

The Time value is either the GPS Time of the measurement, or the estimated delay of the measurement from the time when the aiding message is sent and measurement was valid. The convention used depends on a Bit 15 of the Details field. If time delay is used (Bit 15 is zero), then the delay value is taken from the least significant byte of the Time value for a maximum delay of 255 milliseconds.

(2)

The Heading Standard Deviation is used by the Kalman filter to merge the Heading Measurement into the final solution. A deviation value of zero causes the message to be ignored. A deviation value too small for the current heading estimates may cause instability in the final heading results.

(3)

The Heading Measurement is in True Heading with North at 0 degrees and East at +90 degrees.


Message Payload Length: 12 Bytes

Description: Magnetometer Vector Applicable



0 U4 msec Time

(1)

4 U2 Bit field Details:


(1)

Bits 14..0:

1 = GPS Time

(Reserved, send as zero)

6

8

10

I2

I2

I2

Relative units

Relative units

Relative units

X magnetic component

Y magnetic component

Z magnetic component

(2)

Notes:

(1)


(2)

Units for the magnetic components may be selected arbitrarily. The maximum vector value should be high enough to provide good resolution, but low enough to avoid saturating the 16-bit signed integer field. A scaled range of ±10000 counts would be a good choice. Internally, the MIDG IIC will convert the vector components to a normalized unit vector for use as a measurement.


5.3 Message: AID_POS

(1)

Message 20 Bytes

(3)

Description: Position Aiding Applicable



0 U4 msec Time

(2)

4 U2 Bit fields Details and Vertical Position Standard Deviation:


(2)

1 = GPS Time

14:

(3)

1 = ECEF

13:

12:

Bits 11..0: as

Vertical Standard Deviation

(5)

0. 1 m

6 U2 0.1 m Horizontal Standard Deviation

(3,5)

8

12

16

I4

I4

I4 cm cm, 10

-7 cm, 10

-7

deg

deg

ECEF X, or Altitude

(3)

ECEF Y, or Longitude

ECEF Z, or Latitude

Notes:

(1)

This message has not yet been implemented and is non-functioning. It is presented for reference only, and is subject to change without notice.

(2)

The Time value is either the GPS Time of the measurement, or the estimated delay of the measurement from the time when the aiding message is sent and measurement was valid. The convention used depends on a Bit 15 of the Details field. If time delay is used (Bit 15 is zero), then the delay value is taken from the least significant

byte of the Time value for a maximum delay of 255 milliseconds.

(3)

If Bit 14 of Details is set (ECEF coordinates), the message must be full length. If it is cleared (Altitude/Lon/Lat), then a short message that includes a Horizontal Standard

Deviation of zero and ends with the Altitude field (8 th

..11

th

bytes of the Payload) is accepted. The Payload Length in this case is 12 bytes.

(4)

If Bit 13 of Details is set, the MIDG IIC assumes it must calculate a bias for the altitude measurement when internal GPS data is available.

(5)

The Standard Deviation values are used by the Kalman filter to merge the Position Measurement(s) into the final solution. A deviation value too small for the current heading estimates may cause instability in the final position results. If a Standard Deviation field is zero, it indicates that the associated measurement should not receive

an update: e.g., a packet that updates the Latitude and Longitude, but not the Altitude, would set the Vertical Standard Deviation (Bits 11..0 of Details) to zero.



Description: Velocity Aiding



Payload Length: 14 Bytes (0x0E)

(2)


0 U4 msec Time

(1)

4 U2

0.1 m/s

Details and speed standard deviation:


(1)

1 = GPS Time

14:

0

Speed only

(2)

Bit

Bits 13..12: (Reserved, send zero)

Bits 11..0: Vertical Speed Standard Deviation

(2,3)

6

8

10

I2

I2

I2 cm/s cm/s cm/s

Up Velocity (or total Velocity Magnitude if Bit 14 is set)

(2)

East Velocity

North Velocity

12 U2 0.1 m/s Horizontal Speed Standard Deviation

(3)

Notes:

(1)


(2)

Bit 14 of Details set indicates the Up Velocity is actually the absolute value of the total speed through space, and Bits 11-0 are the Standard Deviation of this speed measurement. If Bit 14 of Details is set, then all elements of the message after Up Velocity are ignored, and may be omitted by the sender. The Payload Length in this case is 8 bytes.

(3)

The Standard Deviation values are used by the Kalman filter to merge the Velocity Measurement(s) into the final solution. A deviation value too small for the current heading estimates may cause instability in the final velocity results. If a Standard Deviation field is zero, it indicates that the associated measurement should not receive an update: e.g., a packet that updates the East and North velocities, but not the Up Velocity, would set the Horizontal Speed Standard Deviation to zero; if Bits 11..0 of Details are zero, then the Up Velocity is not used in the measurement update.


5.5 Message: AID_AIR

(1)

Message

Description: Air Data Aiding

Payload Length: 12 Bytes (0x0C)

Applicable INS



0 U4 msec Time

(2)

4 U2 Bit fields

0.1 m/s

Details and airspeed standard deviation


(2)

1 = GPS Time

Bits 14..12: (Reserved, send as zero)

Bits 11..0: True Airspeed Standard Deviation

(3)

6 U2 0.1 m/s True Airspeed

(4)

8 U2

Bit fields

Angle of Attack Details:

Bits 15..12: Standard Deviation

(5)

Bits 11..0: Angle of Attack

(6)

10 U2 Bit fields Angle of Slip Details:

Bits 15..12: Standard Deviation

(5)

Bits 11..0: Angle of Slip

(6)

Notes:

(1)

This message has not yet been implemented and is non-functioning. It is presented for reference only, and is subject to change without notice.

(2)


(3)

The Standard Deviation value for True Airspeed is used by the Kalman filter to merge the Speed Measurement into the final solution. A deviation value too small for the current speed estimates may cause instability in the final velocity results. If a Standard Deviation field is zero, it indicates that the measurement should not receive an update.

(4)

The provided airspeed is expected to be the ground speed plus the current wind, so that if the actual wind is estimated and removed from this measurement, it will be equivalent to the ground speed.

(5)

The Standard Deviation fields for Angle of Attack and Angle of Slip represent the standard deviations of the angle measurement. The actual deviation applied with the measurement is the deviation 4-bit value times 2 plus 1. A deviation value of 0 = 1 degree, 1 = 3 degrees, 2 = 5 degrees, … , 15 = 31 degrees.

(6)

The Angle of Attack and Angle of Slip are represented as 12-bit scaled signed integesr that represents approximately ±90 degrees. The scale factor is 90/2048, which gives slightly better than 0.05 degree resolution. For example, 123 = 5.4 degrees.


6 Miscellaneous MIDG IIC Input Messages. Several message are provided for commanding and providing information to the MIDG IIC. Miscellaneous input messages are:

¶

ID 30 RTCM RTCM differential correction data

ID 99 RESET System reset

¶

Due to undocumented changes in GPS modules by the manufacturer, not all MIDG IIC units support the RTCM Message. As it is impossible to determine in the field if the message is available, this message should not be used in firmware versions below 2.3. This message is not available in firmware versions

2.3.1 and higher.

RTCM

(1)

Message

Description: RTCM DGPS corrections

Payload Length: Variable




0 BN RTCM data for differential GPS corrections

(2)

Notes:

(1)

Due to undocumented changes in GPS modules by the manufacturer, not all MIDG IIC units support the RTCM Message. As it is impossible to determine in the field if the message is available, this message should not be used in firmware versions below 2.3. This message is not available in firmware versions 2.3.1 and higher.

(2)

RTCM corrections are provided to the MIDG IIC as a stream of bytes. Typically, GPS ground stations that create differential GPS corrections provide a serial stream of these corrections to the user. The contents of this stream must be encapsulated in this packet and provided to the MIDG IIC. The MIDG IIC accepts RTCM message types 1, 2, 3, and 9.


Description: Software Reset Command





0 U4 Reset Code Value must be 0x01310655 for the reset to occur


7 Configuration. Configuration messages provide access to the setup information of the MIDG IIC. This includes the selected mode of operation, message rates, output formats, etc. Configuration operations use two MBI messages: CFG_SET (Message 35) and CFG_QUERY (Message 36).

7.1 Configuration Set Message (CFG_SET). The CFG_SET Message is used to set parameters of the MIDG IIC internal configuration. The general form of this message is:

SYNC_0 SYNC_1 ID

Hex: 0x81 Hex: 0xA1 Hex: 0x23

Dec: 129 Dec: 161 Dec: 35

COUNT

CHECKSUM RANGE

PAYLOAD_1

CFG_ITEM

PAYLOAD_2 PAYLOAD_N CHKSUM_0 CHKSUM_1

The ID for the CFG_SET Message is 35 (0x23), with the first byte of the Payload being the specific CFG_ITEM being set. The balance of the Payload is configuration specific to the

CFG_ITEM . The details for each CFG_ITEM are outlined in the sections below.

The MIDG IIC responds to each CFG_SET Message with either an Configuration Acknowledge Message (CFG_ACK) if the CFG_ITEM operation has been successful, or a

Configuration Not-Acknowledge Message (CFG_NAK) if the operation was not successful.

Message

Description: Acknowledge (sent by MIDG IIC upon success)





0

1

U1

U1

Message_ID

CFG_ITEM

ID = 35 (0x23)

CFG_ITEM

, indicating this is a reply to CFG_SET

number that was successfully changed

Message

Description: Not-Acknowledge (sent by MIDG IIC upon failure )





0

1

2

U1

U1

U1

Message_ID

CFG_ITEM

Code

ID = 35 (0x23)

CFG_ITEM

, indicating this is a reply to CFG_SET

number that was unsuccessfully changed

Failure codes:

1 Wrong number of parameters

2 Bad CFG_ITEM number

3 Invalid request

4 Change would exhaust the serial port bandwidth

5 Subsystem busy – retry message


7.1.3 Message: CFG_SET: BAUD_RATE

(1)

Description: Set serial communication baud rate

Message ID: 35 (0x23)



0

1

U1

U1

CFG_ITEM

Code

CFG_ITEM = 1 (0x01)

Baud Rate:

Notes:

(1)

Changes take effect on reset.

1 = 57600

2 = 38400

3 = 19200

4 = 9600

7.1.4 Message: CFG_SET: PROTOCOL

(1)

Description: Set serial communication protocol




0

1

U1

U1

CFG_ITEM

Code

CFG_ITEM = 2 (0x02)

Protocol

(1)

Notes:

(1)

Changes take effect on reset. The only valid protocol is Microbotics Binary Interface Protocol.






7.1.5 Message: CFG_SET: FORMAT Message ID: 35 (0x23)

Description: Set output format for position and velocity





0 U1 CFG_ITEM CFG_ITEM = 3 (0x03)

1 U1 Bit field Solution Status:

Bits 4-7: (Reserved, send zero)

Bits 2-3: Position Format

0 = ECEF

1 = ENU Relative

(1)

2,3 = LLA

Format

0 = ECEF

Bit

1 = ENU

0: ENU position relative to first fix

(1)

Notes:

(1)

If ENU Relative is selected for Position Format, the position will be relative to either the first GPS fix (Bit 0 set) since reset or a location specified in configuration (Bit 0 cleared).

7.1.6 Message: CFG_SET: RUN_MODE

Description: Set MIDG IIC Run Mode

Message ID: 35 (0x23) Payload Length: 2 Bytes (0x02)




0

1

U1

U1

CFG_ITEM

Code

CFG_ITEM = 4 (0x04)

Run Mode select value:

0 = IMU Mode

1 = Vertical Gyro Mode

2 = INS Mode


7.1.7 Message: CFG_SET: MSG_DIV

Description: Set message interval divider

Message ID: 35 (0x23) Payload Length: 3 Bytes (0x03)





1 U1 Value Output Message ID for which the divisor is to be set

2 U1 Value Message Rate Divisor: 0, 1..255

(1)

Notes:

(1)

If the Message Rate Divisor is non-zero, the update rate will be (50 / Message Rate Divisor) Hz. If the Message Rate Divisor is zero, the specific message requested will be disabled, although it may still be queried.

7.1.8 Message: CFG_SET: POS_REF

Description: Set ENU Relative position reference







1

2

U1

U2

(Reserved, send zero)

(Reserved, send zero)

4

8

12

I4

I4

I4 cm cm cm

X Position, ECEF coordinates

Y Position, ECEF coordinates

Z Position, ECEF coordinates

(1)

Notes:

(1)

The specified location is used as the reference point against which relative ENU Relative position is calculated.


7.1.9 Message: CFG_SET: XFORM Message ID: 35 (0x23) Payload Length: 8 Bytes (0x08)

IIC Applicable Modes: IMU, VG, INS



0 U1 CFG_ITEM CFG_ITEM = 10 (0x0A)

1 U1 (Reserved, send zero)

2

4

6

I2

I2

I2

0.01 deg

0.01 deg

0.01 deg

Transform Yaw

(1)

Transform Pitch

Transform Roll

Notes:

(1)

The Yaw, Pitch, and Roll indicate the Euler angles that define the direction cosine matrix to rotate a vector in the vehicle coordinates to a vector in the MIDG IIC sensor coordinates. The rotation is taken Yaw, Pitch, Roll

Message

Description: Set Transform from Platform to MIDG IIC





0 U1 CFG_ITEM CFG_ITEM = 11 (0x0B)

1 U1 Bit fields Magnetometer operation settings:

Bit 7: (Reserved, send zero)

Bits 6-4: Internal magnetometer aiding Threshold Level

(1)

Bit 3: Use velocity vector for heading even when turning

Bit 2: Use velocity vector for heading

(2)

Bit

Bit

1: Enable internal magnetometer in VG Mode

0: Enable internal magnetometer in INS Mode

2

4

6

I2

I2

I2

Relative units

Relative units

Relative units

X axis magnetometer bias

(3)

Y axis magnetometer bias

Z axis magnetometer bias

Notes:

(1)

The internal magnetometer will not be used if the current heading accuracy is better than the selected Threshold Level. The Threshold Levels correspond to 1 sigma error estimates as follows:

Threshold Error Estimate (1 sigma)

0 0.5 degree

1 1.0 degree

2 2.0 degrees

3 4.0 degrees

4 8.0 degrees

5 12.0 degrees

6 20.0 degrees

7 30.0 degrees

(2)

Bit 2 allows the velocity vector, from the GPS or an external measurement, to be used as heading aiding. This assumes that the MIDG IIC is aligned with the vehicle such that heading is equivalent to direction of motion, and is generally applicable for ground vehicles. If the velocity vector is different from heading when turning, select Bit 3 also.

(3)

The provided bias values are subtracted from the magnetometer data.


7.1.11 Message: CFG_SET: CFG_SAVE

(1)

Description: Save configuration to NV memory




Payload Length: 1 Byte (0x01)



Notes:

(1)

This configuration message must be issued for any configuration changes to be preserved across resets.

7.1.12 Message: CFG_SET: CFG_LOAD

(1)

Message ID: 35 (0x23) Payload Length: 1 Byte (0x01)





Notes:

(1)

This configuration message resets the MIDG IIC configuration information to the values stored in NV memory.

7.1.13 Message: CFG_SET: CFG_ERASE

(1)


Description: Erase configuration in NV memory, reset to default



Payload Length: 1 Byte (0x01)



Notes:

(1)

This configuration message erases the configuration in the non-volatile memory and resets the configuration in the MIDG IIC to its Factory default values. This erasure also forces the NV Configuration Valid flag in the STATUS Message (Bit 7) to remain reset until a new configuration is saved via a CFG_SET: CFG_SAVE Message.


7.2 Configuration Query Message (CFG_QUERY). The CFG_QUERY Message is used to query the parameters of the MIDG IIC internal configuration. The message takes on two forms: CFG_QUERY: GENERAL where a specific CFG_ITEM is being queried, or the CFG_QUERY: INFO where MIDG IIC Product Information is being queried.

The MIDG IIC responds to each CFG_QUERY: GENERAL Message with either an Query Acknowledge Message (QUERY_ACK) if the operation has been successful, or a Query Not-

Acknowledge Message (QUERY_NAK) if the operation was not successful. The MIDG IIC responds to each CFG_QUERY: INFO Message with an Information Acknowledge

Message (INFO_ACK).

7.2.1 Message: CFG_QUERY: GENERAL

Description: Query status of CFG_ITEM

Message ID: 36 (0x24) Payload Length: 1 Byte (0x01)




0 U1 CFG_ITEM CFG_ITEM number being queried (See CFG_SET Messages above)

Message

Description: Acknowledge (sent by MIDG IIC upon success)


(1)




0 U1 CFG_ITEM CFG_ITEM number that was successfully queried

(1)

1 BN Configuration data for the CFG_ITEM queried

(1)

Notes:

(1)

The Payload of a successful CFG_QUERY: GENERAL message has the same format as the corresponding CFG_SET Message for the specific CFG_ITEM requested, with the data indicating the actual values present in the MIDG IIC internal configuration.

Message

Description: Not-Acknowledge (sent by MIDG IIC upon failure )





0

1

2

U1

U1

U1

Message_ID

CFG_ITEM

Code

ID = 36 (0x24)

CFG_ITEM

, indicating this is a reply to CFG_QUERY: GENERAL

number that was unsuccessfully queried

Failure code:

2 Bad CFG_ITEM number


7.2.4 Message: CFG_QUERY: INFO

Byte Number

0

1

U1

U1

Units

Code


CFG_ITEM



CFG_ITEM = 20 (0x14)

Product ID queried:


, indicating this is a query for CFG_QUERY: INFO

2 = Part Number

4 = Support Key

5 = Firmware Version

7.2.5 Message: INFO_ACK Message ID: 36 (0x24)

Description: Product Information (sent by the MIDG IIC)




(1)


0 U1 CFG_ITEM CFG_ITEM = 20 (0x14) , indicating this is a reply to CFG_QUERY: INFO

1 U1 Code Product ID queried

2 BN ASCII string Information requested returned as a NULL-terminated ASCII string

(1)

Notes:

(1)

The requested information is returned after the Product ID byte as a NULL-terminated string. If the requested Product ID is not recognized, or the information is not available, the reply will be a NULL string (a single byte of 0x00).


icrobotics, Inc.

28 Research Drive, Suite G

Hampton, Virginia 23666

+1- 757-865-7728

Innovative Navigation and Controls www.microboticsinc.com

MIDG IIC SPECIFICATIONS

(SIS90031C and SIS90031C-SR)

December 15, 2011

The MIDG IIC is a GPS aided inertial navigation system (INS) for use in applications requiring attitude, position, velocity, acceleration, and angular rates for navigation or control. An internal GPS receiver measures position and velocity and passes this information to the data fusion processor to be combined with the inertial data to generate an optimal solution. An internal three-axis magnetometer provides a magnetic heading reference when needed.

A build option (SIS90031C-SR) uses Pin 8 as a Time Mark input to allow GPS time tagging of the rising edge of an input signal pulse.

Features

 Full INS Solution

 Low Power

 Light Weight

 Small Size

Standard Sensor Axes (can be changed by user)

Specifications subject to change without notice. C 1 of C6

icrobotics, Inc.



+1- 757-865-7728


MIDG IIC Specifications 1

Power Requirements

Input Voltage

Power



December 15, 2011

10 VDC - 32 VDC

1.2W max (including GPS antenna)

GPS Antenna 2

Connector Type

Antenna Power

RF Power Input

Antenna Pre-Amplifier

Measurements

Angular rate (all axes)

Range

Non-Linearity

Noise Density

3dB Bandwidth

Acceleration (all axes)

Range

Non-Linearity

Noise Density

3dB Bandwidth

Attitude Accuracy (pitch and roll, with GPS)

50-Ohm SMA, right hand thd

+5V at center conductor, 25 ma max

-145 dBm min, -61dBm max

45 dB maximum gain

±300 °/sec

0.1% of FS

0.1 °/sec / √Hz

20 Hz

±6 g

0.3% of FS

150 μg / √Hz

20 Hz

0.4° (1 σ)

Heading Accuracy (with GPS and maneuvering)

Position Accuracy

2° (1 σ)

2m (CEP) with WAAS/EGNOS available, 3 m (CEP) otherwise

Velocity Accuracy

Altitude Accuracy

< 0.2 m/s

3m (SEP) with WAAS/EGNOS available, 5m (SEP) otherwise

Data Output Rates

Environment

Temperature

Humidity

Survival Shock

Survival Vibration

1 Typical values.

2

See section on active/passive antennas.

Position , Velocity, attitude, rates, accelerations - 50 Hz

GPS measurements - 4 Hz

-40° C to 85° C, operating and storage

10% to 90% RH, non-condensing

6 g rms

100 g, 8ms., ½ sine

, 10 Hz to 2000 Hz, random


icrobotics, Inc.



+1- 757-865-7728


Output

Electrical

Physical

Pulse Per Second 3

Data Format



December 15, 2011

RS422 async., 115200 baud (configurable), 8-N-1

Complementary pair, each side TTL compatible

Microbotics Binary Protocol

Size

Weight

1.500” W x .810” H x 1.725” D

55 grams

3 One side used for Trigger Input when Time Mark Option ordered (SIS90031C-SR).


icrobotics, Inc.



+1- 757-865-7728




December 15, 2011

MIDG IIC MOUNTING DIMENSIONS

FRONT

0.810 [20.57]

0.576 [14.63]

0.277 [7.04]

0.575 [14.61]

0.975 [24.77]

0.363 [9.22]

1.725 [43.82]

1.000 [25.40]

0.063 [1.60] 1.375 [34.93]

1.500 [38.10]

Specifications subject to change without notice.

BOTTOM

1MM SCREW ON MATING CONNECTOR --

MATING SCREW REQUIRES .035 (.9MM)

ALLEN HEAD SOCKET DRIVE

MOUNTING HOLES FOR 0-80 UNF SCREWS

4 PLCS

SCREW INSERTION .187 [4.75] MAX

C4 of C6



December 15, 2011

MIDG IIC CONNECTOR PIN-OUT

PIN 3

PIN 10 PIN 5

PIN 4 PIN 1

(VIEWED FROM FACE OF MIDG CONNECTOR)

CONNECTOR PIN-OUT

(Colors refer to mating connector cable)

PIN 1 BLACK Rb (Receive pos: MARK high, SPACE low)

PIN 2 BROWN Ra (Receive neg: MARK low, SPACE high)

PIN 3 RED PPS_N (1 PPS pulse: Idle high, falling active edge)

PIN 4 ORANGE Power In (10-32 VDC, 1.2 w max)

PIN 5 YELLOW Digital Ground (do not use for Power Return)

PIN 6 GREEN Tb (Transmit pos: MARK high, SPACE low)

PIN 7 BLUE

PIN 8 VIOLET

Ta (Transmit neg: MARK low, SPACE high)

PPS_P/Aux * (1 PPS pulse: Idle low, rising active edge)

PIN 9 GRAY

PIN 10 WHITE

Power Return

Shield

Note: Power Return and Shield connected to Digital Ground

(* Pin 8 Rising-edge Trigger Input with T ime Mark Option - SIS90031C-SR)

STANDARD 1 PPS OUTPUT SIGNALS

1 second

Active Edges

*

PIN 8

100 ms

NOTE: If the MIDG IIC is equipped with the Time Mark option

(SIS90031C-SR), pin 8 becomes the Tirigger Input. A rising edge on this input causes the TIM_TM message to be sent by the MIDG IIC indicating the time of the rising edge to within 1 msec. The input is TTL compatible (high recognized above 2V, low recognized below 0.4V, do not exceed 5V).


icrobotics, Inc.



+1- 757-865-7728




December 15, 2011

GPS ANTENNA REQUIREMENTS

1. Antenna mounting must be non-magnetic and not use a magnetic mount, as this magnet will interfere with the MIDG magnetometers.

2. Antenna and Ground Plane. A GPS antenna ground plane is recommended.

Antenna ground plane of 7 x 7 cm (2.75 x 2.75 in.), minimum, is recommended for use with the GPS antenna available from Microbotics, Inc (Part Number A-GPS5-

SMA).

3. Note on Active/Passive Antennas. (The following information is supplied by GPS receiver manufacturer.) Passive antennas contain only the radiating element, e.g. the ceramic patch or the helix structure. The use of an active antenna is always advisable if the RF-cable length between receiver and antenna exceeds about 10 cm. Care should be taken that the gain of the LNA inside the antenna does not lead to an overload condition at the receiver. A gain of 15-21 dB is usually sufficient, even for cable lengths up to 5 m. There’s no need for the antenna LNA gain to exceed 26 dB for use with this receiver. With short antenna cables, gains in excess of 25dB may swamp the

GPS RF front end.

When comparing gain measures of active and passive antennas, one has to keep in mind that the gain of an active antenna is composed of two components: the antenna gain of the passive radiator, given in dBic; and the LNA power gain, given in dB. A low antenna gain cannot be compensated by high LNA gain. If a manufacturer provides one total gain figure, it is not sufficient to judge the quality of the antenna.

One would need information on antenna gain (in dBic), amplifier gain, and amplifier noise figure.

ALERT REGARDING ANTENNA CONNECTION: 5v power for active antennas is supplied via the MIDG GPS SMA connector. The GPS antenna must never be connected or disconnected while the MIDG is powered. Connecting or disconnecting the GPS antenna with power applied to the MIDG may damage the GPS receiver, and will void the MIDG warranty.


™

ANT-GPS-UC-xxx DATA SHEET

Product Dimensions

0.56”

(14.2)

1.79”

(45.5)

Description

Side

UC Series GPS antennas deliver high-gain, low- noise performance in a rugged and cosmetically attractive package. They feature a wide operating temperature and low current consumption. The antennas attach via a standard SMA, Part 15 compliant RP-SMA or MCX connector.

2.00”

(50.8)

Features

Top















Compact

High-gain, low-noise design

Low current consumption

Wide operating temperature

Fully weatherized / waterproof

Rugged & damage-resistant

Magnetic mount

Electrical Specifications

Bottom



























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

Center Freq.

Bandwidth

Impedance

VSWR

Ant. Gain 90°

Polarization

Axial Ratio 90°

1575.42MHz

9MHz minimum

50 ohms

1.5 maximum

3.0dBi

RHCP

3.0dBi maximum

System Gain

Noise

Input Voltage

28dBi typ.

2.2dB maximum

3.0-5.0 VDC

Power Consum. 20mA maximum

Oper. Temp. -31°F to +185°F (-35°C to +85°C)

Mounting

Cable

Magnetic

RG-174

197” +/-6” (5m +/-150mm)

Cable Length

Connector SMA, RP-SMA or MCX male

Ordering Information







ANT-GPS-UC-SMA (with SMA connector)

ANT-GPS-UC-RPS (with RP-SMA connector)

ANT-GPS-UC-MCX (with MCX connector)

Antenna Factor

MCX- male

SMA,

RP-SMA

159 Ort Lane Merlin, OR 97532 www.antennafactor.com

541-956-0931 (phone) 541-471-6251 (fax) Rev 2-9-11

Attachment E

Installation Directory Tree

1 Introduction. This attachment is designed to show the user where all of the files for the MIDG Series INS/GPS are installed on the user's PC or laptop. There may be differences in the root path of the directory depending on the installation path chosen by the user during installation; however, the rest of the installation will be the same.

2 Start Menu. During the installation process of the MIDG Software and

Utilities, a start menu item will be created named "Microbotics, Inc." This start menu contains all of the shortcuts for the software, utilities, and documents included in the software package (Figure 1).

3 Directory File Tree. The directory file tree shows all of the files and their respective installation locations. The Microbotics Installer is designed to maintain all files installed by Microbotics within a central file location for ease of search and access.

Figure 1.Start Menu Listing for Installed

Software


Page E1 of E2


Page E2 of E2

MIDG Series INS/GPS User Manual

MIDG SERIES INS/GPS

USER MANUAL

09 January 2012

TABLE OF CONTENTS

Section

Heading

Page

Attachment A

SLC2JUSB

MIDG IIC Message Specification for Firmware V2.1.x and Higher

MIDG IIC MOUNTING DIMENSIONS

MIDG IIC CONNECTOR PIN-OUT

STANDARD 1 PPS OUTPUT SIGNALS

*

NOTE: If the MIDG IIC is equipped with the Time Mark option

(SIS90031C-SR), pin 8 becomes the Tirigger Input. A rising edge on this input causes the TIM_TM message to be sent by the MIDG IIC indicating the time of the rising edge to within 1 msec. The input is TTL compatible (high recognized above 2V, low recognized below 0.4V, do not exceed 5V).

GPS ANTENNA REQUIREMENTS

Attachment E

Installation Directory Tree

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