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D Logs summary
MiLLennium Command Descriptions Manual 145
GPGRS GPS Range Residuals for Each Satellite
Range residuals can be computed in two ways, and this log reports those residuals. Under mode 0, residuals output
in this log are used to update the position solution output in the
GPGGA message. Under mode 1, the residuals are
re-computed after the position solution in the
GPGGA message is computed. The GPSCard computes range
residuals in mode 1. An integrity process using
GPGRS would also require GPGGA (for position fix data), GPGSA
(for DOP figures), and GPGSV (for PRN numbers) for comparative purposes.
Structure:
Example:
$GPGRS,192911.0,1,-13.8,-1.9,11.4,-33.6,0.9,6.9,-12.6,0.3,0.6,-22.3,,
*65[CR][LF]
NOTE: If the range residual exceeds ± 99.9, then the decimal part will be dropped. Maximum value for this
field is ± 999. The sign of the range residual is determined by the order of parameters used in the calculation as
follows:
range residual = calculated range - measured range.
$GPGRS utc mode
res res
res res
res res res res res res res res
*xx [CR][LF]
Field Structure Field Description Symbol Example
1 $GPGRS Log header $GPGRS
2 utc UTC time of position (hours/minutes/seconds/ decimal seconds) hhmmss.ss 192911.0
3 mode Mode 0 =residuals were used to calculate the position given in
the matching GGA line (apriori) (not used by GPSCard)
Mode 1 =residuals were recomputed after the GGA position was
computed (preferred mode)
x 1
4 - 15 res Range residuals for satellites used in the navigation solution.
Order matches order of PRN numbers in GPGSA.
x.x,x.x,..... -13.8,-1.9,11.4,-33.6,0.9,
6.9,-12.6,0.3,0.6, -22.3
16 *xx Checksum *hh *65
17 [CR][LF] Sentence terminator [CR][LF]