GPS Overview
There are two ways to receive GPS information. There is Cellular modem GPS available in the LTE modules that support GPS, and there is a dedicated GPS/Dead Reckoning module (IRM-GNSS-ADR) which provides more robust capabilities.
The IR1833 and IR1835 have a slot for a dedicated GPS field-replaceable unit (FRU) module, which will be used in addition to the one integrated in the LTE module, for more accurate dead reckoning performance. The part number is IRM-GNSS-ADR.
IRM-GNSS-ADR hardware is capable of supporting various GNSS constellations. Please inquire with your sales representative for a roadmap of support of additional constellations on the IRM-GNSS-ADR module.
Modem based GPS cannot provide the coordinates when there are no satellites in line of sight. The GPS module with DR capabilities provide the coordinates even when there are no satellites in line of sight.
With the addition of the dedicated GPS/Dead Reckoning module, along with Cellular module, there will be two sources of GPS location information. These two are independent and they can be retrieved using different CLIs:
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Cellular modem GPS information can be seen using the show cellular <slot number> gps command.
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GPS/DR module GPS info uses the show platform hardware gps detail command.
The following table provides a comparison of Modem based GPS and GPS/Dead Reckoning module based GPS.
Parameters |
Modem Based GPS |
GPS/Dead Reckoning Module |
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---|---|---|---|---|
Type |
Cellular Modem based GPS |
FRU Based GPS |
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PIDs Supported |
All of the IR1800 series |
Only on IR1835 and IR1833 |
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Configuration Modes |
Standalone mode |
No configuration is available to select modes. The device automatically selects either standalone | dead-reckoning mode based on satellites reception. |
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Number of satellites needed for co-ordinates |
Standalone mode – 4 |
If a signal is received from 4 or more satellites, standalone GPS co-ordinates will provide co-ordinates else dead-reckoning will provide the gps co-ordinates. |
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Satellites Supported in show command |
Co-ordinates seen in show commands output is based only on GPS. |
Co-ordinates seen in the output of show commands is based only on GPS satellites. However, nmea traffic will show GPS, Gallileo, and Glonass. |
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Initial Calibration Required |
No |
Yes |
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Co-ordinates in Absence of Satellite |
No Co-ordinates will be acquired and it stays in acquiring status. |
The device seamlessly shifts to Dead-reckoning mode and provide co-ordinates based on calculation done by the FRU. The FRU takes into account vehicle speed, direction, last acquired coordinates from the GPS satellite, accelerometer and gyroscope. For dead reckoning to work, the device should have acquired the co-ordinates at least once before the loss of signal from satellite after the router boot up. |
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Device Name of Controller to use for Configuration |
controller cellular <slot> |
controller gps-dr |
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CLI to enable feature |
lte gps enable lte gps mode standalone
|
dead-reckoning enable |
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CLI to configure nmea |
lte gps nmea |
nmea is automatically enabled once “dead-reckoning enable” is configured |
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CLI to configure nmea udp socket |
lte gps nmea ip udp <source_ip> <destination_ip> <destination_port> |
dead-reckoning nmea udp <source_ip> <destination_ip> <destination_port> |
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CLI to verify configuration under show running-config |
show run | sec controller cellular<slot> |
show run | sec controller gps-dr |
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Show commands to verify gps output |
show cellular <slot> gps show controller cellular <slot> | inc gps |
show platform hardware gps detail show platform hardware gps mode show platform hardware gps status show platform hardware gps dead-reckoning |
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Access to GPS nmea traffic on IOx side |
Supported |
Supported |
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Debug Command |
debug cellular<slot> messages gps debug cellular<slot> messages nmea |
debug platform hardware gps_dr all | dr | gps | nmea |
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Yang Model Support |
Yes |
Yes |