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VECTOR COMPACT GPS COMPASS
NMEA-0183 Version
GPS Compass
User Guide
Part No. 875-0346-0 Rev. A1
This device complies with part 15 of the FCC Rules. Operation is subject to the following two conditions:
(1) This device may not cause harmful interference, and
(2) this device must accept any interference received, including interference that may cause undesired operation.
Patents
SI-TEX GNSS products may be covered by one or more of the following patents:
U.S. Patents
6111549 6876920 7400956 8000381 8214111
6397147 7142956 7429952 8018376 8217833
6469663 7162348 7437230 8085196 8265826
6501346 7277792 7460942 8102325 8271194
6539303 7292185 7689354 8138970 8307535
6549091 7292186 7808428 8140223 8311696
6711501 7373231 7835832 8174437 8334804
6744404 7388539 7885745 8184050 RE41358
6865465 7400294 7948769 8190337
Australia Patents
2002244539
2002325645
2004320401
Other U.S. and foreign patents pending.
Notice to Customers
Contact your local dealer for technical assistance. To find the authorized dealer near you:
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Vector Compact GPS Compass
User Guide
Contents
Chapter 1 Introduction
Chapter 2 VECTOR COMPACT Installation
GPS Reception .................................................................................... 6
Vector Compact Environmental Considerations ......................................... 6
Mounting Orientation ............................................................................. 9
Vector Compact Alignment ....................................................................... 11
Vector Compact Dimensions ............................................................... 12
Power/Data Cable Considerations ...................................................... 14
Connecting to a Power Source .................................................................. 21
Connecting the Vector to External Devices .......................................... 22
Power/Data Cable Considerations ............................................................ 22
Power/Data Cable Pin-out Specifications .................................................. 23
iii
Contents
Chapter 3 Operation
GPS Operation .................................................................................. 28
Differential Operation.......................................................................... 29
Supplemental Sensors ....................................................................... 31
Common Commands and Messages .................................................... 36
Appendix A Troubleshooting............................................................ 41
Appendix B Specifications ............................................................... 45
End User License Agreement ............................................................ 49
Warranty Notice ................................................................................. 52
iv
Contents
Chapter 1: Introduction
Overview Parts
List
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Vector Compact GPS Compass
User Guide
Overview
The Vector Compact™ GPS Compass is based upon SI-TEX GNSS’ exclusive Crescent ® and Crescent Vector™ II technology.
The Vector Compact is a complete GPS compass and position system in a single enclosure that requires only one power/data cable connection. With its serial support and ease of installation, the Vector Compact is the perfect solution for marine-based applications.
The Vector Compact is an integrated system that houses the following:
• Crescent and Crescent Vector II technology
• Dual integrated GPS antennas
• Power supply
• Single axis gyro
• Tilt sensor on each axis (X and Y axes)
The gyro and tilt sensors are present to improve system performance and to provide backup heading information in the event that a GPS heading is not available due to signal blockage.
Crescent Vector II technology supports multiple RF front ends - enabling tighter coupling of measurements from separate antennas for use in heading-based products. Users will achieve excellent accuracy and stability due to Crescent’s more accurate code phase measurements, improved multipath mitigation, and fewer components.
The Vector Compact’s GPS antennas are separated by 13.5 cm between their phase centers, resulting in better than 2° rms heading performance. The
Vector Compact provides heading and position updates of up to 10 Hz and delivers position accuracy of better than 1.0 m 95% of the time when using differential GPS corrections from Space Based Augmentation Systems (SBAS).
The Vector Compact also features SI-TEX GNSS’ exclusive COAST™ technology that enables SI-TEX GNSS receivers to utilize old differential
GPS correction data for 40 minutes or more without significantly affecting the position quality. The Vector Compact is less likely to be affected by differential signal outages due to signal blockages, weak signals, or interference when using COAST.
2
Chapter 1: Introduction
.
Parts List
Note: The Vector Compact’ parts comply with IEC 60945 Section 4.4: “exposed to the weather.”
The Vector Compact GPS Compass and the power/data cable (accessory item) are the only two required components
Table 1-1: Parts list for Serial version of the Vector Compact
Part Name Qty Part Number
Vector Compact GPS Compass (Serial)
Screw Housing Caps
Serial Cable, 5m
Mounting Screws
Mounting Base
Mounting Nut
Screw Housing Cap O-Rings
1
1
2
1
2
1
2
804-0114-0
675-0173-0
051-0372-0
675-1199-000#
676-0035-0
676-1021-000#
681-1066-0
This User Guide is available for download from the SI-TEX GNSS website at www.si-tex.com
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Vector Compact GPS Compass
User Guide
4
Chapter 1: Introduction
Chapter 2: Vector Compact Installation
Mounting Location
Mounting Orientation
Mounting Options
Powering the Vector
Compact
Connecting the Vector Compact to External Devices
5
Vector Compact GPS Compass
User Guide
Mounting Location
This section provides information on determining the best location for the
Vector Compact.
GPS Reception
When considering where to mount the Vector Compact, consider the following
GPS reception recommendations:
• Ensure there is a clear view of the sky available to the Vector
Compact so the GPS and SBAS satellites are not masked by obstructions that may reduce system performance.
• Since the Vector Compact computes a position based on the internal GPS antenna element, mount the Vector Compact where you desire a position with respect to the GPS antenna (located on the side of the recessed arrow on the underside of the enclosure).
• Locate any transmitting antennas away from the Vector Compact by at least several feet to ensure tracking performance is not compromised, giving you the best performance possible.
• Make sure there is enough cable length to route into the vessel to reach a breakout box or terminal strip.
• Do not locate the antenna where environmental conditions exceed those specified in Table B-5 on page 48.
Vector Compact Environmental Considerations
The Vector Compact is designed to withstand harsh environmental conditions; however, adhere to the following limits when storing and using the Vector Compact:
• Operating temperature: -30°C to +70°C (-22°F to +158°F).
• Storage temperature: -40°C to +85°C (-40°F to +185°F).
• Humidity: 100% non-condensing.
6
Chapter 2: Installation
VHF Interference
VHF interference from devices such as cellular phones and radio transmitters may interfere with GPS operation. For example, if installing the
Vector Compact near marine radios consider the following:
• VHF marine radio working frequencies (Channels 1 to 28 and 84 to
88) range from 156.05 to 157.40 MHz. The L1 GPS working center frequency is 1575.42 MHz. The bandwidth is +/- 2MHz to +/- 10 MHz, which is dependent on the GPS antenna and receiver design (see next page).
• VHF marine radios emit strong harmonics. The 10th harmonic of
VHF radio, in some channels, falls into the GPS working frequency band, which may cause the SNR of GPS to degrade significantly.
• The radiated harmonic signal strength of different brands/models varies.
• Follow VHF radio manufacturers’ recommendations on how to mount their radios and what devices to keep a safe distance away.
• Hand-held 5W VHF radios may not provide suitable filtering and may interfere with the Vector Compact’s operation if too close.
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Vector Compact GPS Compass
User Guide
Before installing the Vector Compact use the following diagram to ensure there are no nearby devices that may cause VHF interference.
VHF Antenna
1.5 m radius at top
(minimum)
Use these minimum distances to determine where to place the Vector
Compact
1.0 m radius at base
(minimum)
Figure 2-1: Vector Compact distance from nearby VHF radios
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Chapter 2: Installation
Mounting Orientation
The Vector Compact outputs heading, pitch, and roll readings regardless of the orientation of the antennas. However, the relation of the antennas to the boat’s axis determines whether you will need to enter a heading, pitch, or roll bias. The primary antenna is used for position. The primary and secondary antennas, working in conjunction, output heading, pitch, and roll values.
Note: Regardless of which mounting orientation you use, the Vector
Compact provides the ability to output the heave of the vessel. This output is available via the $GPHEV message. For more information on this message refer to refer to GPS Technical Reference available from the SI-TEX GNSS website at www.SI-TEXgnss.com
.
Parallel Orientation: The most common installation is to orient the Vector
Compact parallel to, and along the centerline of, the axis of the boat. This provides a true heading. In this orientation:
• If you use a gyrocompass, you can enter a heading bias in the Vector
Compact to calibrate the physical heading to the true heading of the vessel.
• You may need to adjust the pitch/roll output to calibrate the measurement if the Vector is not installed in a horizontal plane.
Perpendicular Orientation: You can also install the antennas so they are oriented perpendicular to the centerline of the boat’s axis. In this orientation:
• You will need to enter a heading bias of +90° if the primary antenna is on the starboard side of the boat and -90° if the primary antenna is on the port side of the boat.
• You will need to configure the receiver to specify the GPS antennas are measuring the roll axis using $JATT,ROLL,YES.
• You will need to enter a roll bias to properly output the pitch and roll values.
• You may need to adjust the pitch/roll output to calibrate the measurement if the Vector is not installed in a horizontal plane.
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Vector Compact GPS Compass
User Guide
Figure 2-2 and Figure 2-3 provide mounting orientation examples.
Forward motion
Recessed arrow located on bottom of enclosure
Figure 2-2: Recommended orientation and resulting signs of HPR values
Forward motion
Figure 2-3: Alternate orientation and resulting signs of HPR values
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Chapter 2: Installation
Vector Compact Alignment
The top of the Vector Compact enclosure incorporates sight design features to help you align the enclosure with respect to an important feature on your vessel.
To use the sights, center the small post on the opposite side of the enclosure from you, within the channel made in the medallion located in the center of the enclosure top as shown in Figure 2-4 and Figure 2-5. Alignment accuracy when looking through the site (Figure 2-4)and (Figure 2-5) is approximately
+/- 1°.
Figure 2-4: Long site alignment channel
Figure 2-5: Long sight alignment center post
If you have another accurate source of heading data on your vessel, such as a gyrocompass, you may use its data to correct for a bias in Vector Compact alignment within the Vector Compact software configuration (PocketMax or
VectorPC).
Alternatively, you can physically adjust the heading of the Vector Compact so that it renders the correct heading measurement; however, adding a software offset is an easier process.
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Vector Compact GPS Compass
User Guide
Mounting Options
The Vector Compact allows for both pole or flush mounting. Follow directions below for detailed mounting directions.
Vector Compact Dimensions
Figure 2-6 illustrates the physical dimensions of the Vector Compact.
Figure 2-6: Vector Compact dimensions
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Chapter 2: Installation
Vector Compact dimensions with adapter
13
Vector Compact GPS Compass
User Guide
Power/Data Cable Considerations
Before mounting the Vector Compact consider the following regarding power/data cable routing:
• Cable must reach an appropriate power source
• Cable may connect to a data storage device, computer, or other device that accepts GPS data
• Avoid running the cable in areas of excessive heat
• Keep cable away from corrosive chemicals
• Do not run the cable through door or window jams
• Keep cable away from rotating machinery
• Do not crimp or excessively bend the cable
• Avoid placing tension on the cable
• Remove unwanted slack from the cable at the Vector Compact end
• Secure along the cable route using plastic wraps
Improperly installed cable near machinery can be dangerous
14
Chapter 2: Installation
Flush Mount
The bottom of the Vector Compact contains two holes for flush mounting the unit to a flat surface (Figure 2-7). The flat surface may be something you fabricate per your installation, an off-the-shelf item (such as a radar mounting plate), or an existing surface on your vessel.
Note: SI-TEX GNSS does not supply the mounting surface hardware. You must supply the appropriate fastening hardware required to complete the installation of the Vector Compact.
Figure 2-7: Flush mounting with holes in the Vector Compact
Note: You do not necessarily need to orient the antenna precisely as you can enter a software offset to accommodate for any bias in heading measurement due to installation.
15
Vector Compact GPS Compass
User Guide
Before flush mounting the Vector Compact
• Determine your mounting orientation. See “Mounting Orientation” on page 9 for more information.
• Choose a location that meets the mounting location requirements.
• Using the fixed base as a template, mark and drill the mounting holes as necessary for the mounting surface.
Flush mounting the Vector Compact
1. Mark the mounting hole centers and connector center on the mounting surface.
2. Place the Vector Compact over the marks to ensure the planned hole centers align with the true hole centers (adjusting as necessary).
3. Use a center punch to mark the hole centers.
4. Drill the mounting holes to a diameter of 6.8mm (0.26 in) appropriate for the surface.
5. Drill the connector hole to a diameter of 28.6mm (1.13 in) appropriate for the surface.
6. Pull the cable through the center connector hole and attach the cable directly to the Vector Compact, ensuring the connector clicks.
7. Place the Vector Compact over the mounting holes and insert the mounting screws through the top of the Vector Compact and through the mounting surface.
8. Use two M6 washers and M6 nuts to secure the Vector
Compact to the mounting plate (washers and nuts not included).
When installing the Vector Compact, hand tighten only.
Damage resulting from over-tightening is not covered by the warranty.
Note: See “Vector Compact Dimensions” on page 12 for information on routing the power/data cable.
16
Chapter 2: Installation
Pole Mount
Before pole mounting the Vector Compact
• Vector Compact provides roll measurements when mounted in any preferred orientation. If accurate roll measurements are important to your use case, we recommend mounting the Vector Compact perpendicular to the vessel’s axis. If roll measurements are less important, install the Vector Compact parallel with the vessel’s axis.
• Choose a location that meets the mounting location requirements.
• Mark and drill the mounting holes as necessary for the threaded pole.
17
Vector Compact GPS Compass
User Guide
Pole mounting instructions for Vector Compact (Inside Pole)
Required tools: 5 mm Allen key for M6 screws and adjustable wrench to tighten jam nut
1. Insert mating cable through both the jam nut and 1” (25.4mm) mounting adapter base
2. Place the jam nut on the pole followed by the 1” (25.4mm) adapter base. Hand tighten the base to the desired orientation.
3. Adjust the jam nut to secure the orientation.
4. Connect the mating end of the cable to the Vector Compact connector located on the bottom of the unit.
5. Insert the base adapter into Vector Compact by placing the tongue of the base into the groove of the Vector Compact unit. When the tongue is properly seated in the groove, the rest of the base can be pressed into place to create a smooth seam between the base and
Vector Compact unit.
6. Use 5 mm Allen key to fasten two M6 screws to secure Vector
Compact onto adapter. Use 15 in-lb torque
7. Insert each o-ring onto a plastic cap
8. Install plastic cap with o-ring onto Vector Compact unit
(rectangular notch faced towards the outside)
9. Align and set the direction of Vector Compact unit, while using the jam nut to secure the unit (hand-tighten).
Over-tightening may damage the system. This is not covered under warranty.
18
Chapter 2: Installation
Pole mounting instructions for Vector Compact (Outside Pole)
Required tools: 5 mm Allen key for M6 screws and adjustable wrench to tighten jam nut
1. Place the jam nut on the pole followed by the 1” (25.4mm) adapter base. Hand tighten the base to the desired orientation.
2. Adjust the jam nut to secure the orientation.
3. Run the cable throughout the vessel making sure to leave enough slack to mate the NMEA 2000 cable to both the NMEA 2000 backbone and the Vector Compact unit.
4. Run the NMEA 2000 cable through the opening in the side of the pole mounting adapter. And then connect the mating end of the cable to the V104 connector located on the bottom of the unit.
5. Insert the base adapter into Vector Compact by placing the tongue of the base into the groove of the Vector Compact unit. When the tongue is properly seated in the groove, the rest of the base can be pressed into place to create a smooth seam between the base and
Vector Compact unit.
6. Use 5 mm Allen key to fasten two M6 screws to secure Vector
Compact onto adapter. Use 15 in-lb torque
7. Insert each o-ring onto a plastic cap
8. Install plastic cap with o-ring onto Vector Compact unit
(rectangular notch faced towards the outside)
9. Align and set the direction of Vector Compact unit, while using the jam nut to secure the unit (hand-tighten).
Over-tightening may damage the system. This is not covered under warranty.
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Vector Compact GPS Compass
User Guide
Connecting the power/data cable
1. Align the cable connector key-way with the Vector Compact connector key.
Key-way alignment
2. Rotate the cable ring clockwise until it locks. The locking action is firm, but you will feel a positive “click” when it has locked.
Note: See “Vector Compact Dimensions” on page 12 for information on routing the power/data cable.
20
Chapter 2: Installation
Powering the Vector Compact
Power Considerations
For best performance use a clean and continuous power supply. The Vector
Compact power supply features reverse polarity protection but will not operate with reverse polarity.
See Table B-3 on page 47 for complete power specifications.
Connecting to a Power Source
Before you power up the Vector Compact you must terminate the wires of the power cable as required. There are a variety of power connectors and terminals on the market from which to choose, depending on your specific requirements.
Do not apply a voltage higher than 36 VDC. This will damage the receiver and void the warranty.
To interface the Vector Compact power cable to the power source:
• Connect the red wire of the cable’s power input to DC positive (+)
• Connect the black wire of the cable’s power input to DC negative (-)
The Vector Compact will start when an acceptable voltage is applied to the power leads of the extension cable.
Electrical Isolation
The Vector Compact’s power supply is isolated from the communication lines and the PC-ABS plastic enclosure isolates the electronics mechanically from the vessel (addressing the issue of vessel hull electrolysis).
21
Vector Compact GPS Compass
User Guide
Connecting the Vector Compact to External
Devices
Power/Data Cable Considerations
The Vector Compact uses a single 15 m (49 ft) cable for power and data input/output.
Figure 2-8: Power/data cable, 15 m
The receiver end of the cable is terminated with an environmentally sealed
12-pin connection while the opposite end is unterminated and requires field stripping and tinning.
Depending on the application and installation needs, you may need to shorten this cable. However, if you require a longer cable run than 15 m, you can bring the cable into a break-out box that incorporates terminal strips, within the vessel.
When lengthening the cable keep the following in mind:
• To lengthen the serial lines inside the vessel, use 20-gauge twisted pairs and minimize the additional wire length.
• When lengthening the power input leads to the Vector Compact, ensure the additional voltage drop is small enough that your power system can continue to power the system above the minimum voltage of the system. Wire of 18-gauge or larger should also be used.
• Minimize RS-232 cable length to ensure reliable communication
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Chapter 2: Installation
Power/Data Cable Pin-out Specifications
Figure 2-9 show the power/data cable pin-out, while Table 2-1 shows the cable’s pin-out specifications.
Figure 2-9: Power/data cable pin assignment
6
7
4
5
8
2
3
1
1
Table 2-1: Power/data cable pin-out
Pin Function
CH-GND
DGND
RXB
Power Input
Power Ground
TXB
RXA
TXA
1PPS
Wire Color
Drain
Brown
Blue
Red
Black
Green
Orange
Purple
Yellow
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Vector Compact GPS Compass
User Guide
Serial Ports
The Vector Compact offers position and heading data via two full-duplex
(bi- directional) RS-232 serial ports. In addition to outputting data, these ports are used for firmware upgrades.
Selecting Baud Rates and Message Types
When selecting your baud rate and message types, use the following calculation to determine your baud rate for your required data throughput.
Messages * Message output rate * Message length (bytes) * bits in byte
Ex: 5 * 10Hz * 40 bytes * 10 = 20,000 bits/sec
For information on message output rates refer to GPS Technical Reference available from the SI-TEX GNSS website at www.SI-TEXgnss.com
.
Configuring the Ports
You may configure Port A or Port B of the GPS receiver to output any combination of data that you want. Port A can have a different configuration from Port B in terms of data message output, data rates, and the baud rate of the port. This allows you to configure the ports independently based upon your needs. For example, if you want one generalized port and one heading-only port, you can configure the ports as follows:
• Port A to have GPGGA, GPVTG, GPGSV, GPZDA, and GPHDT all output at 1 Hz over a 9600 baud rate
• Port B to have GPHDT and GPROT output at their maximum rate of
10 Hz over a 19200 baud rate
A personal computer (PC) typically uses a DB9-male connector for RS-232 serial port communications.
Note: For successful communications use the 8-N-1 protocol and set the baud rate of the Vector Compact’s serial ports to match that of the devices to which they are connected. Flow control is not supported.
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Chapter 2: Installation
Default Parameters
Table 2-2 and Table 2-3 provide details on the default port settings, available baud rates, differential age, elevation mask, and default differential mode.
Note: Use the $JSAVE command to save changes you make to the Vector
Compact’s configuration for the changes to be present in subsequent power cycles.
Table 2-2: Default port settings
Port Baud Rate NMEA Messages
Port A
(RS-232)
Port B
(RS-232)
Power
RED (+)
BLK (-)
19200
19200
GPGGA, GPVTG, GPGSV, GPZDA,
GPHDT, GPROT
GPGGA, GPVTG, GPGSV, GPZDA,
GPHDT, GPROT
6 - 36 VDC
Update Rate
1 Hz
1 Hz
Table 2-3: Additional default settings
Parameter Specification
Max DGPS age (correction age)
Elevation mask
Differential mode
2700 seconds
5°
SBAS (WAAS/EGNOS)
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Vector Compact GPS Compass
User Guide
26
Chapter 2: Installation
Chapter 3: Operation
GPS Overview
Vector Compact
Overview
Common Commands and Messages
27
Vector Compact GPS Compass
User Guide
GPS Overview
For your convenience, both the GPS and SBAS (WAAS, MSAS, GAGAN and
EGNOS) operation of the Vector Compact features automatic operational algorithms. When powered for the first time, the Vector Compact performs a "cold start," which involves acquiring the available GPS satellites in view and the SBAS differential service.
If SBAS is not available in your area, an external source of RTCM SC-104 differential corrections may be used. If you use an external source of correction data, it must support an eight data bit, no parity, one stop bit configuration (8-N-1).
GPS Operation
The GPS receiver is always operating, regardless of the DGPS mode of operation. The following sections describe the general operation of the
Vector Compact’s internal GPS receiver.
Note: Differential source and status have no impact on heading, pitch, or roll. They only have an impact on position and heave.
Automatic Tracking
The Vector Compact’s internal GPS receiver automatically searches for GPS satellites, acquires the signals, and manages the navigation information required for position and tracking.
Receiver Performance
The Vector Compact works by finding four or more GPS satellites in the visible sky. It uses information from the satellites to compute a position within 3 m. Since there is some error in the GPS data calculations, the
Vector Compact also tracks a differential correction. The Vector Compact uses these corrections to improve its position accuracy to better than 1.0 m.
There are two main aspects of GPS receiver performance:
• Satellite acquisition
• Position and heading calculation
28
Chapter 3: Operation
When the Vector Compact is properly positioned, the satellites transmit coded information to the antennas on a specific frequency. This allows the receiver to calculate a range to each satellite from both antennas. GPS is essentially a timing system. The ranges are calculated by timing how long it takes for the signal to reach the GPS antenna. The GPS receiver uses a complex algorithm incorporating satellite locations and ranges to each satellite to calculate the geographic location and heading. Reception of any four or more GPS signals allows the receiver to compute three-dimensional coordinates and a valid heading.
Differential Operation
The purpose of differential GPS (DGPS) is to remove the effects of selective availability (SA), atmospheric errors, timing errors, and satellite orbit errors, while enhancing system integrity. Autonomous position capabilities of the
Vector Compact will result in position accuracies of 3 m 95% of the time. In order to improve position quality to better than 1.0 m 95%, the Vector
Compact is able to use differential corrections received through the internal SBAS demodulator or externally-supplied RTCM corrections.
Automatic SBAS Tracking
The Vector Compact automatically scans and tracks SBAS signals without the need to tune the receiver. The Vector Compact features two-channel tracking that provides an enhanced ability to maintain a lock on an SBAS satellite when more than one satellite is in view. This redundant tracking approach results in more consistent tracking of an SBAS signal in areas where signal blockage of a satellite is possible.
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Vector Compact GPS Compass
User Guide
Vector Compact Overview
The Vector Compact provides accurate and reliable heading and position information at high update rates. To accomplish this task, the Vector
Compact uses a high performance GPS receiver and two antennas for GPS signal processing. One antenna is designated as the primary GPS antenna and the other is the secondary GPS antenna. Positions computed by the
Vector Compact are referenced to the phase center of the primary GPS antenna. Heading data references the vector formed from the primary GPS antenna phase center to the secondary GPS antenna phase center.
The heading arrow located on the bottom of the Vector Compact enclosure defines system orientation. The arrow points in the direction the heading measurement is computed (when the antenna is installed parallel to the fore-aft line of the vessel). The secondary antenna is directly above the arrow.
Primary antenna
0.135 m baseline
Figure 3-1: Secondary antenna’s search volume
Note: The Vector Compact moving base station algorithm only uses GPS to calculate heading. Differential corrections are not used in this calculation and will not affect heading accuracy.
30
Chapter 3: Operation
Supplemental Sensors
The Vector Compact has an integrated gyro and two tilt sensors. The gyro and tilt sensors are enabled by default. Both supplemental sensors are mounted on the printed circuit board inside the Vector Compact.
The sensors act to reduce the search volume, which improves heading startup and reacquisition times. This improves the reliability and accuracy of selecting the correct heading solution by eliminating other possible, erroneous solutions. Table 3-1 on page 32 provides a sensor operation summary.
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Vector Compact GPS Compass
User Guide
Table 3-1: Sensor operation summary
Feature Normal Operation Coasting (no GPS)
Heading
Pitch
Roll
GPS
GPS
Inertial sensor
Gyro
Inertial sensor
Inertial sensor
SI-TEX GNSS’ GPS Technical Reference describes the commands and methodology required to recalibrate, query, or change the sensors status.
Tilt Aiding
The Vector Compact’ accelerometers (internal tilt sensors) are factorycalibrated and enabled by default. This improves heading solution beyond the volume associated with just a fixed antenna separation. This is because the Vector Compact knows the approximate inclination of the secondary antenna with respect to the primary antenna. The search space defined by the tilt sensor will be reduced to a horizontal ring on the sphere’s surface by reducing the search volume. This considerably decreases startup and reacquisition times (see Figure 3-2).
Tilt angle
Figure 3-2: Vector Compact’s tilt aiding
Gyro Aiding
The Vector Compact’ internal gyro offers several benefits. It reduces the sensor volume to shorten reacquisition times when a GPS heading is lost because the satellite signals were blocked. The gyro provides a relative change in
32
Chapter 3: Operation angle since the last computed heading, and, when used in conjunction with the tilt sensor, defines the search space as a wedge-shaped location (see
Figure 3-3).
Figure 3-3: Vector Compact’s gyro aiding
The gyro aiding accurately smoothes the heading output and the rate of turn. It provides an accurate substitute heading for a short period depending on the roll and pitch of the vessel, ideally seeing the system through to reacquisition. The gyro provides an alternate source of heading, accurate to within 1º per minute for up to three minutes, in times of GPS loss for either antenna. If the outage lasts longer than three minutes, the gyro will have drifted too far and the Vector Compact begins outputting null fields in the heading output messages. There is no user control over the timeout period of the gyro.
Calibration, which is set at the factory, is required for the gyro to remove latency from the heading solution as well as provide backup heading when
GPS is blocked. The receiver will calibrate itself after running for a while but it may be important to follow the manual calibration instructions if you want to guarantee performance quickly after powering up the receiver.
With the gyro enabled, the gyro is also used to update the post HTAU smoothed heading output from the GPS heading computation. This means that if the HTAU value is increased while gyro aiding is enabled, there will be no lag in heading output due to vehicle maneuvers. SI-TEX GNSS’ GPS
Technical Reference includes information on setting an appropriate HTAU value for the application.
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Vector Compact GPS Compass
User Guide
Time Constants
The Vector Compact incorporates user-configurable time constants that can provide a degree of smoothing to the heading, pitch, rate of turn (ROT), course over ground (COG), and speed measurements. You can adjust these parameters depending on the expected dynamics of the vessel. For example, increasing the time is reasonable if the vessel is very large and is not able to turn quickly or would not pitch quickly. The resulting values would have reduced “noise,” resulting in consistent values with time.
However, if the vessel is quick and nimble, increasing this value can create a lag in measurements. Formulas for determining the level of smoothing are located in SI-TEX GNSS’ GPS Technical Reference. If you are unsure on how to set this value, it is best to be conservative and leave it at the default setting.
Note: For heading and rate of turn there is no lag once the gyro is calibrated and enabled.
Heading time constant: Use the $JATT,HTAU command to adjust the level of responsiveness of the true heading measurement provided in the
$GPHDT message. The default value of this constant is 20.0 seconds of smoothing when the gyro is enabled. The gyro is enabled by default, but can be turned off. By turning the gyro off, the equivalent default value of the heading time constant would be 0.5 seconds of smoothing. This is not automatically done and therefore you must manually enter it. Increasing the time constant increases the level of heading smoothing and increases lag.
Pitch time constant: Use the $JATT,PTAU command to adjust the level of responsiveness of the pitch measurement provided in the $PSAT,HPR message. The default value of this constant is 0.5 seconds of smoothing.
Increasing the time constant increases the level of pitch smoothing and increases lag.
Rate of Turn (ROT) time constant: Use the $JATT,HRTAU command to adjust the level of responsiveness of the ROT measurement provided in the
$GPROT message. The default value of this constant is 2.0 seconds of smoothing. Increasing the time constant increases the level of ROT smoothing.
34
Chapter 3: Operation
Course Over Ground (COG) time constant: Use the $JATT,COGTAU command to adjust the level of responsiveness of the COG measurement provided in the $GPVTG message. The default value of this constant is
1.1 seconds of smoothing. Increasing the time constant increases the level of COG smoothing. COG is computed using only the primary GPS antenna and its accuracy depends upon the speed of the vessel (noise is proportional to 1/speed). This value is invalid when the vessel is stationary, as tiny movements due to calculation inaccuracies are not representative of a vessel’s movement.
Speed time constant: Use the $JATT,SPDTAU command to adjust the level of responsiveness of the speed measurement provided in the $GPVTG message. The default value of this constant is 0.0 seconds of smoothing.
Increasing the time constant increases the level of speed measurement smoothing.
Watchdog
The watchdog is a timer that is controlled by the software that monitors if the heading is lost. The watchdog software is compliant with IEC 60945.
35
Vector Compact GPS Compass
User Guide
Common Commands and Messages
Note: When selecting your baud rate and message types, use the following calculation to determine your baud rate for your required data throughput.
Messages * Message output rate * Message length (bytes) * bits in byte
Ex: 5 * 10Hz * 40 bytes * 10 = 20,000 bits/sec
For information on message output rates refer to GPS Technical Reference available from the SI-TEX GNSS website at www.SI-TEXgnss.com
.
Table 3-2 below through Table 3-4 provide brief descriptions of common commands and messages for the Vector Compact. Refer to the SI-TEX
GNSS’ GPS Technical Reference for more detailed information.
Table 3-2: Commands
Command Description
$JAGE Specify maximum DGPS (COAST) correction age (6 to 8100 seconds)
Query or specify receiver application firmware $JAPP
$JASC Specify ASCII messages to output to specific ports (see ASCII messages in Table 3-3)
Specify RS-232, RS-422 (output) communication rate $JBAUD
$JBIN
$JDIFF
$JGEO
$JI
$JOFF
Specify binary messages to output to specific ports (see
Table 3-4)
Query or specify differential correction mode
Query or specify SBAS for current location and SBAS satellites
Query unit’s serial number and firmware versions
Turn off all data messages
$JQUERY,GUIDE Query accuracy suitability for navigation
$JRESET Reset unit’s configuration to firmware defaults
$JSAVE Save session’s configuration changes
36
Chapter 3: Operation
In Table 3-3 the Info Type value is one of the following:
• P = Position
• V = Velocity, Time
• H = Heading, Attitude
• S = Sats, Stats, Quality
Table 3-3: NMEA 0183 and other messages
Message
$GPDTM
$GPGGA
$GPGLL
$GPGNS
$GPGRS
$GPGSA
$GPGST
$GPGSV
*$GPHDG
*$GPHDM
*$GPHDT
$GPHEV
$GPRMC
*$GPROT
S
S
S
P
P
P
P
H
P
H
Info
Type
S
H
H
H
Description
IEC
Approved
Message
Datum reference
GPS position and fix data
Geographic position - lat/long
GNSS position and fix data
GNSS range residual (RAIM)
GNSS DOP and active satellites
GNSS pseudo range error statistics and position accuracy
GNSS satellites in view
Provides magnetic deviation and variation for calculating magnetic or true heading
*see last bullet in Note at end of this table
Magnetic heading (based on GPS-derived heading and magnetic declination)
*see last bullet in Note at end of this table
GPS-derived true heading
*see last bullet in Note at end of this table
Yes
Yes
No
Yes
Heave value (in meters) Yes
Recommended minimum specific GNSS data Yes
GPS-derived rate of turn (ROT)
*see last bullet in Note at end of this table
Yes
Yes
Yes
Yes
Yes
Yes
Yes
Yes
37
Vector Compact GPS Compass
User Guide
Table 3-3: NMEA 0183 and other messages (continued)
Message
Info
Type
Description
IEC
Approved
Message
$GPRRE
$GPVTG
$GPZDA
$PASHR
$PSAT,GBS
$PSAT,HPR
S
V
V
H
S
H
$PSAT,INTLT H
Range residual and estimated position error Yes
COG and ground speed Yes
Time and date
Time, heading, roll, and pitch data in one message
Satellite fault detection (RAIM)
Yes
No
Proprietary NMEA message that provides heading, pitch, roll, and time in single message
Proprietary NMEA message that provides the pitch and roll measurements from the internal inclinometers (in degrees)
Yes
No
Yes
$RD1 S SBAS diagnostic information Yes
$TSS1 H Heading, pitch, roll, and heave message in the commonly used TSS1 message format
No
Notes:
• The GP of the message is the talker ID.
• You can change the message header for the HDG, HDM, HDT, and ROT messages to either GP or HE using the $JATT,NMEAHE command. For more information refer to GPS Technical Reference available from the SI-TEX GNSS website at www.SI-TEXgnss.com
.
• GPGRS, GPGSA, GPGST, and GPGSV support external integrity checking.
They are to be synchronized with corresponding fix data (GPGGA or
GPGNS).
• For information on outputting roll, pitch, and heave data in one message refer to GPS Technical Reference available from the SI-TEX GNSS website at www.SI-TEXgnss.com
.
38
Chapter 3: Operation
Table 3-4: Binary messages
$JBIN
Message
Description
95
96
97
98
99
1
2
80
93
94
GPS position
GPS DOPs
SBAS
SBAS ephemeris data
Ionosphere and UTC conversion parameters
Satellite ephemeris data
Code and carrier phase
Processor statistics
Satellites and almanac
GPS diagnostics
Table 3-5: Parameters specific to $JATT command
Parameter Description
COGTAU
CSEP
EXACT
FLIPBRD
GYROAID
HBIAS
HELP
HIGHMP
HRTAU
Set/query COG time constant (0.0 to 3600.0 sec)
Query antenna separation
Enable/disable internal filter reliance on the entered antenna separation
Turn the flip feature on/off
Enable/disable gyro
Set/query heading bias (-180.0º to 180.0º)
Show the available commands for GPS heading operation and status
Set/query the high multipath setting for use in poor GPS environments
Set/query ROT time constant (0.0 to 3600.0 sec)
Query Specify
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
39
Vector Compact GPS Compass
User Guide
Table 3-5: Parameters specific to $JATT command (continued)
Parameter Description
HTAU Set/query heading time constant (0.0 to 3600.0 sec)
Note: Higher
HTAU values combined with disabling the gyro will result in significant lag time
Enable/disable level operation LEVEL
MSEP
NEGTILT
NMEAHE
Manually set or query antenna separation
Enable/disable negative tilt
Change the HDG, HDM, HDT, and ROT message headers between Talker IDs (GP and HE)
Set/query pitch/roll bias (-15.0º to 15.0º) PBIAS
PTAU
ROLL
SEARCH
SPDTAU
SUMMARY Display a summary of the current Crescent
Vector settings
TILTAID Enable/disable accelerometer, pre-calibrated
TILTCAL
Set/query pitch time constant (0.0 to 3600.0 sec)
Configure for roll or pitch GPS orientation
Force a new GPS heading search
Set/query speed time constant (0.0 to 3600.0 sec)
Calibrate accelerometers
Query Specify
X X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
40
Chapter 3: Operation
Appendix A: Troubleshooting
41
Vector Compact GPS Compass
User Guide
Table A-1 provides troubleshooting for common problems.
Table A-1: Troubleshooting
Symptom Possible Solution
Receiver fails to power
No data from Vector
Compact
Random data from
Vector Compact
No GPS lock
• Verify polarity of power leads
• Check integrity of power cable connectors
• Check power input voltage (6 to 36 VDC)
• Check current restrictions imposed by power source (minimum available should be > 1.0 A)
• Check receiver power status to ensure the receiver is powered (an ammeter can be used for this)
• Verify desired messages are activated (using
PocketMax, Vector PC or $JSHOW in any terminal program)
• Ensure the baud rate of the Vector Compact matches that of the receiving device
• Check integrity and connectivity of power and data cable connections
• Verify the RTCM or binary messages are not being output accidentally (send a $JSHOW command)
• Ensure the baud rate of the Vector Compact matches that of the remote device
• Potentially, the volume of data requested to be output by the Vector Compact could be higher than the current baud rate supports (try using
19200 as the baud rate for all devices or reduce the amount of data being output)
• Verify the Vector Compact has a clear view of the sky
• Verify the lock status of GPS satellites (this can be done with PocketMax or VectorPC)
42
Appendix A: Troubleshooting
Table A-1: Troubleshooting (continued)
Symptom Possible Solution
No SBAS lock
No heading or incorrect heading value
• Verify the Vector Compact has a clear view of the sky
• Verify the lock status of SBAS satellites (this can be done with PocketMax - monitor BER value)
• Set SBAS mode to automatic with the
$JWAASPRN,AUTO command
Note: SBAS lock is only possible if you are in an appropriate SBAS region; currently, there is limited
SBAS availability in the southern SI-TEX.
• Check CSEP value is fairly constant without varying more than 1 cm (0.39 in)—larger variations may indicate a high multipath environment and require moving the receiver location
• Recalibrate the tilt sensor with $JATT,TILTCAL command if heading is calculated then lost at consistent time intervals
• Heading is from primary GPS antenna to secondary
GPS antenna, so the arrow on the underside of the
Vector Compact should be directed to the bow side
• $JATT,SEARCH command forces the Vector
Compact to acquire a new heading solution
(unless gyro is enabled)
• Enable GYROAID to provide heading for up to three minutes during GPS signal loss
• Enable TILTAID to reduce heading search times
• Monitor the number of satellites and SNR values for both antennas within PocketMax—at least four satellites should have strong SNR values
• Potentially, the volume of data requested to be output by the Vector Compact could be higher than the current baud rate supports (try using
19200 as the baud rate for all devices or reduce the amount of data being output)
•
Intermittent issues potentially caused by an incorrect
HBIAS.
43
Vector Compact GPS Compass
User Guide
Table A-1: Troubleshooting (continued)
Symptom Possible Solution
No DGPS position in external RTCM mode
• Verify the baud rate of the RTCM input port matches the baud rate of the external source
• Verify the pin-out between the RTCM source and the RTCM input port (transmit from the source must go to receive of the RTCM input port and grounds must be connected)
• Ensure corrections are being transmitted to the correct port—using the $JDIFF,PORTB command on
Port A will cause the receiver to expect the corrections to be input through Port B
44
Appendix A: Troubleshooting
Appendix B: Specifications
45
Vector Compact GPS Compass
User Guide
Table B-1 through Table B-5 provide the Vector Compact’s GPS sensor, communication, power, mechanical, and environmental specifications.
Table B-1: GPS sensor specifications
Item Specification
Receiver type
Channels
SBAS tracking
Update rate
Position accuracy
Single Point
1
SBAS
2
Heading accuracy
Heave accuracy
Vector GPS L1 Compass
Two 12-channel, parallel tracking
(Two 10-channel when tracking SBAS)
2-channel, parallel tracking
10 Hz standard (position and heading)
1 m (95%)
3 m (95%)
2° (RMS)
Pitch/Roll accuracy
Rate of turn
< 30 cm (RMS)
3
2° (RMS)
90
°
/s maximum
Cold start
Warm start
Hot start
Heading fix
Compass safe distance
< 60 s typical (no almanac or RTC)
< 20 s typical (almanac and RTC)
< 1 s typical (almanac, RTC, and position)
< 10 s typical (valid position)
Maximum speed
Maximum altitude
30 cm (11.8 in)
3
1,850 kph (999 kts)
18,288 m (60,000 ft)
46
Appendix B: Specifications
Table B-2: Communication specifications
Item Specification
Serial ports
Baud rates
Correction I/O protocol
Data I/O protocol
2 full-duplex RS-232
4800, 9600, 19200, 38400, 57600, 115200
RTCM SC-104
NMEA 0183, Crescent binary
4
Table B-3: Power specifications
Item Specification
Input voltage
Power consumption
Current consumption
Power isolation
Reverse polarity protection
8 to 36 VDC
~ 2 W nominal
165 mA @ 12 VDC
Isolated to enclosure
Yes
Table B-4: Mechanical specifications
Item Specification
Enclosure
Dimensions (not including mount)
UV resistant, white plastic, Geloy CR7520 (ASA)
25.9 L x 12.9 W x 4.5 H (cm)
10.2 L x 5.1 W x 1.8 H (in)
Dimensions (including mount)
25.9 L x 12.9 W x 12.8 H (cm)
10.2 L x 5.1 W x 5.0 H (in)
Weight (not including mount)
Weight (including mount)
0.42 kg (0.9 lb)
0.51 kg (1.1 lb)
47
Vector Compact GPS Compass
User Guide
Table B-5: Environmental specifications
Item Specification
Operating temperature
Storage temperature
Water and Dust
Humidity
Vibration
EMC
-30°C to +70°C (-22°F to +158°F)
-40
°
C to +85
°
C (-40
°
F to +185
°
F)
IP69
100% non-condensing
IEC 60945
CE (IEC 60945 Emissions and Immunity) FCC Part
15, Subpart B
CISPR22
F
1
Depends on multipath environment, number of satellites in view, satellite geometry, no SA, and ionospheric activity.
2
Depends on multipath environment, number of satellites in view, SBAS coverage and satellite geometry.
3
Based on a 40-second time constant.
4
SI-TEX GNSS proprietary
48
Appendix B: Specifications
Index
A
alarm watchdog 35 alignment 11 automatic
SBAS tracking 29 tracking 28
C
cable See power/data cable 14
COGTAU 35, 39 commands (common) 36 common commands and messages 36 communication specifications 47 connect to a power source 21 to external devices 22 course over ground time constant 35
E
electrical isolation 21 environmental considerations 6 specifications 48 environmental considerations 6 external devices 22
F
flush mount 15
G
GPHEV 9, 37
GPS automatic SBAS tracking 29 automatic tracking 28 operation 28 overview 28 receiver performance 28 reception 6 sensor specifications 46 gyro aiding 32
H
heading time constant 34 heave 9, 37 accuracy 46
HRTAU 34, 39
HTAU 34, 40
L
long sight alignment 11
M
mechanical specifications 47 message (common) 36 mounting alignment 11 cable considerations 14 environmental considerations 6 flush mount 15
GPS reception 6 location 6 orientation 9 parallel orientation 9 perpendicular orientation 9 pole mount 17
VHF interference 7
49
Index
O
orientation for mounting 9
P
parallel mounting 9 part numbers 3 parts list 3 perpendicular mounting 9 pitch time constant 34 pole mount 17 power connecting to a power source 21 considerations 21 electrical isolation 21 specifications 47
PTAU 34, 40
R
rate of turn (ROT) time constant 34 receiver performance 28
RS-232 22, 23, 24, 25, 36, 47
S
sensor specifications 46 short site alignment 11
SPDTAU 35, 40 specifications communication 47 environmental 48
GPS sensor 46 mechanical 47 power 47 speed time constant 35 supplemental sensors 31
T
tilt aiding 32 time constants 34
COGTAU 35
HRTAU 34
HTAU 34
PTAU 34
SPDTAU 35 tracking automatic 28 automatic SBAS 29 troubleshooting 42
V
VHF interference 7
W
watchdog 35
50
Customer Service
If you encounter problems during the installation or operation of this product, or cannot find the information you need, please contact Sitex Customer Service.
The contact numbers and e-mail address for Sitex Customer Service are:
Sitex Main Office…….………..+1-631-996-2690
Sitex Fax..………………….…..+1-631-996-2693
Sitex Service E-mail address: [email protected]
Sitex Customer Support E-mail address
:
[email protected]
Sitex Main Office Address:
25 Enterprise Zone Drive, Ste 2
Riverhead, NY 11901
Technical Support is available from 9:00 AM to 5:00 PM Eastern Standard Time, Monday through Friday.
HOW TO OBTAIN SERVICE UNDER THIS WARRANTY
To provide greater flexibility, SI-TEX Marine Electronics gives you the option to obtain service under the warranty by either:
(a) Contacting an authorized SI-TEX Marine Electronics service station
(The closest service station may be found by contacting your dealer of purchase)
OR
(b) Shipping your equipment prepaid via UPS, FED-EX or truck with insurance prepaid to SI-TEX Marine
Electronics. at the address provided below. SI-TEX Marine Electronics will whenever possible, make all repairs covered by Limited Warranty within two weeks of receiving the equipment in New York and return the same to you, freight prepaid.
Please do not use the Mail Service due to delays in tracing lost packages.
(c) You must present a copy of your Purchase Sales Slip at the time you request warranty service.
A product repair case can be started from the support section of our website at www.si-tex.com
SI-TEX CERTIFICATE OF LIMITED WARRANTY
Providing you present valid proof of purchase, SI-TEX Marine Electronics warrants all parts of each new product against defects in material and workmanship under normal use and will repair or exchange any parts proven to be defective at no charge for a period of two years from the original date of purchase, except as provided below under Limited Warranty Exceptions.
Defects will be corrected during normal working hours by an authorized SI-TEX Marine Electronics dealer, service center, or at the SI-TEX office in Riverhead, NY. There will be no charge for repair labor for a period of one year from the date of purchase, except as provided below under Limited Warranty
Exceptions. This Warranty and Proof of Purchase must be made available to the authorized SI-TEX
Marine Electronics service location or dealer at the time of service.
LIMITED WARRANTY EXCEPTIONS
SI-TEX Marine Electronics will not be responsible for equipment which has been subjected to water or lightning damage, accident, abuse, or misuse, nor any equipment on which the serial number has been removed, altered, or mutilated. SI-TEX Marine Electronics assumes no responsibility for damage incurred during installation. This Limited Warranty is effective only with respect to the original purchaser. Any cost associated with transducer replacement, other than the cost of the transducer itself, is specifically excluded from the Limited Warranty.
Travel cost incurred will not be accepted by SI-TEX Marine Electronics
THERE ARE NO WARRANTIES WHICH EXTEND BEYOND THE DESCRIPTION ON THE FACE HEREOF.
SPECIFIC EXCLUSIONS
Charges for overtime, stand-by, holiday, and per diem are specifically excluded from the Limited
Warranty. fuses are consumable items and are not covered by this Limited Warranty.
Installation workmanship or materials, except as provided directly by SI-TEX Marine Electronics are not covered by this Limited Warranty.
SI-TEX Marine Electronics equipment, or parts thereof which have been repaired or altered except by an authorized SI-TEX Marine Electronics dealer or service center are not warranted in any respect.
Transducers, software updates, batteries, magnetrons and microwave components, are items excluded from the two-year warranty and are covered by warranty for a period of one year for both parts and labor.
SI-TEX Marine Electronics will not, at any time assume any costs or labor charges for checkout or external line fuse replacement or problems not found to be at fault in the equipment itself.
THERE ARE NO WARRANTIES OR GUARANTEES EXPRESSED OR IMPLIED WHICH EXTEND
BEYOND THE DESCRIPTION OF THE FACE HEREOF, INCLUDING WARRANTIES OF FITNESS FOR
A PARTICULAR PURPOSE AND MERCHANTABILITY. SI-TEX MARINE ELECTRONICS HAS
NO OTHER LIABILITY TO PURCHASE FOR DIRECT OR CONSEQUENTIAL DAMAGE OR ANY
THEORY INCLUDING ABSOLUTE LIABILITY, TORT, OR CONTRACT. THIS LIMITED WARRANTY
CANNOT BE ALTERED OR MODIFIED IN ANY WAY AND SHALL BE INTERPRETED IN ACCORDANCE
WITH THE LAWS OF THE STATE OF NEW YORK. THIS WARRANTY IS LIMITED TO THE
CONTINENTAL U.S.A., ALASKA, HAWAII, AND CANADA.
MAILING & SHIPPING ADDRESS:
SI-TEX Marine Electronics
25 Enterprise Zone Drive, suite #2
Riverhead, NY 11901
(631) 996-2690
25 Enterprise Zone Drive, Ste 2
Riverhead, NY 11901 USA
Phone:
+
1 631 996 2690.
Fax:
+
1 631 996 2693
Email: [email protected]
www.si-tex.com
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