GPS Compendium

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GPS location format
  • EPSG:900913(Mercator) coordinates.
RSSI calculation
  • Radio send GPS to the application through Repeater, Repeater checks the signal quality measuring Rx antenna signal quality.
Regular GPS
  • Works on Voice channel only.
  • Allows 1 sec. report.
This requires enough free Timeslot time.
Enhanced GPS
  • Since subscribers only send their location response in their reserved windows, collisions do not happen here. 
  • Support for up to 360 location responses per minute per repeater using both slots, while running at 90% capacity, and decrease in the number of channels and associated hardware needed for GPS data transmission.
  • For a window size of 1, support up to 1808 location responses per minute per repeater using both slots, while running at 90% capacity is possible.
Enhanced GPS+CSBK
  • When GPS CSBK data is enabled, twice the number of radios can be supported with a similar GPS success rate.
  • Revert channel required to avoid collision with Voice success rate gets impacted when the voice loading is high.
  • CSBK data requires NAI Data license to be enabled in TRBOnet.
  • Window size 1 - Requires MNIS.
  • According to the memory limitation, 3616 radios for a 2-minute update per repeater using both slots cannot be supported, the maximum number of radios allowed is only 2200. If there are more than 2200 radios, it is recommended to configure the two scheduled slots with two repeaters to share the loading.
  • Window size 2 - Requires MNIS or Control Radio (does not work with IPSC or LCP).
  • For a window size of 2, support up to 896 location responses per minute per repeater using both slots, while running at 90% capacity is allowed.
The Trigger start command is sent over Voice channel, hence take in account, the amount of required voice timeslots to set trigger to whole radio fleet.

CSBK data does not support Basic Privacy, Enhanced Privacy, or any foreseeable privacy features.<br> CSBK data does not support confirmed data delivery mode.

Indoor location updates cannot be sent over CSBK calls.

  • Allowed periodic trigger rates are 7.5 (EGPS+CSBK), 15, 30, 60 and 120 seconds.
  • If the cadence is different, the subscriber responds with a LRRP error message “PROTOCOL_ELEMENT _NOT_SUPPORTED”.
MOTOTRBO Link system does not support the CSBK Data.
GPS Revert, Data Revert.
Enhanced/Scheduled GPS.
Every PTT trigger (Also known as: Caller location or Inband location or Every voice transmission)
  • This feature works only if you are using Motorola firmware R02.20.02.0002 or higher.
  • Operates using CSBK commands.
  • Observation - to activate PTT must be pressed 5 sec minimum.
  • It is confirmed by Motorola that, the latest firmware of subscriber radios can send GPS data only through MNIS and NAI Voice and Data.
Different window reservations within single system
  • Each of two slots of Data repeater can be configured to work with different window size.
  • Radios with smaller window size fit into bigger reserved window size (e.g. Radios with window size 2 compatible with window size 5, 6, 7, 8, 9 and 10, however have no benefits of smaller window size).
  • Regular GPS compatible with reserved window Data repeater, the data will be not sent sent in reserved window, the data send attempt will happen out of reservation period.

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