NMEA-0183 message: GRS

GRS range residuals

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

NOTE – 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)