NMEA-0183 message: GRS

GRS range residuals

The GRS message is used to support the Receiver Autonomous Integrity Monitoring (RAIM).

Because the contents of this NMEA message do not change significantly during a one-second interval, the receiver outputs this message at a maximum rate of 1 Hz.

An example of the GRS message string is:

$GPGRS,220320.0,0,-0.8,-0.2,-0.1, -0.2,0.8,0.6,,,,,,1,*55

GRS message fields

Field	Meaning
0	Message ID $GPGRS Talker ID can be: GA: Galileo GB: BeiDou GP: GPS. To provide information specific to the GPS constellation when more than one constellation is used for the differential position fix. GL: GLONASS. To provide information specific to the GLONASS constellation when more than one constellation is used for the differential position fix. GN: Combined GNSS position. GNSS position fix from more than one constellation, for example, GPS and GLONASS. GQ: QZSS
1	UTC of GGA position fix
2	Residuals: 0: Residuals used to calculate position given in the matching GGA line 1: Residuals recomputed after the GGA position was computed
3–14	Range residuals for satellites used in the navigation solution, in meters
15	Satellite System ID: GP(1), GL(2), GA(3), GB(4), GQ(0)