NavCom LAND-PAK Rev.N - Manual (Page 177)

Technical Reference Manual Rev. N
Blk = All; Blu = IOP w/Internal Radio ; Red = IOP & LBM ; Grn = Engine only
175
$GPGRS
This output message is used to support Receiver Autonomous Integrity Monitoring (RAIM), and
is in compliance with NMEA-0183 Standards version 3.0.
Output
Format:
$GPGRS,time,mode,residual*checksum
Field# Field Name Description
F1 time
UTC time for position fix in hours, minutes, seconds
(hhmmss.ss) (000000.00 to 235959.99)
F2 mode
Mode
0 = residuals were used to calculate the position given in the matching GGA
or GNS sentence
1 = residuals were recomputed after the GGA or GNS position was
computed
F3 residuals
1,2
Range residuals in meters for satellites used in the navigation solution.
3
Order must match order of the satellite ID numbers in GSA. When GRS is
used GSA and GSV are generally required.
F4 Checksum
Example: $GPGRS,021733.00,0, 0.4, 1.8,-0.2,-0.3,-0.8, 0.2, 0.3, 0.3, 0.9,-0.7, 1.1,-0.2*4C
1
If the range residual exceeds 99.9 meters, then the decimal part is dropped,
resulting in a integer (-103.7 becomes -103). The maximum value for this field is
999.
2 The sense or sign of the range residual is determined by the order of
parameters used in calculation. The expected order is:
range residual = calculated range – measured range.
3 When multiple GRS sentences are being sent then their order of transmission
must match the order of corresponding GSA sentences. Listeners shall keep
track of pairs of GSA and GRS sentences and discard data if pairs are
incomplete.