Instruction manual

Command Response Formats Page 103
Command
Example: Enable GRS message on port C
$PASHS,NME,GRS,C,ON followed by output command
$PASHS,OUT,x,NMEA where x is the output port.
$GPGRS
The response message is in the form
$GPGRS,hhmmss.ss,m,sxx.x,sxx.x,sxx.x,....*cc
Range residuals are recomputed after the GGA position is computed. Therefore the mode m is
always 1.
There will be a range residual sxx.x for each satellite used in position computation,
and the order of the residuals matches the order of the satellites in the GSS message.
Table 4.48 shows the structure of the GRS response message. .
Example:
Set: $PASHS,NME,GRS,A,ON
Typical Response:
$GPGRS,180257.50,1,+00.3,-00.4,+00.2,+00.5,+00.7,-00.8*64
Table 4.49 describes a typical GRS response message.
Table 4.48: GRS Structure
Field Description
hhmmss.ss Current UTC time, hhmmss.ss, of GGA position fix in hours, minutes, and seconds hh =
Hours (00 to 23) mm = Minutes (00 to 59) ss.ss = Seconds (00.00 to 59.99)
m Mode, m, used to compute range residuals 0 - Residuals were used to calculate the
position given in the matching GGA line 1 - residuals were recomputed after the GGA
position was computed
sxx.x
sxx.x
sxx.x.....
Range residuals (sign s = + or -, and magnitude xx.x) for each satellite used in position
computation. The order of the residuals matches the order of the satellites in the GSS
message.
*cc Checksum
Table 4.49: Typical GRS Response Message
Item Description
$GPGRS Header
180257.50 Time of position computation
1 Mode
+00.3 Range residual for first SV in GSS message