ashtech DG16 Reference Manual page 289

Table 8.42 outlines the message format.
Parameter
m1 UTC time of the position fix (hhmmss.ss)
c2 Status of the position fix (always A)
• A—Autonomous, position data is valid
• D—Differential, position data valid
• V—Invalid for all values of the Indicator mode
m3 Latitude (ddmm.mmmmmm)
c4 Latitude sector
m5 Longitude (dddmm.mmmmmm)
c6 Longitude sector
f7 Speed over the ground (knots)
f8 Course over the ground (degrees); referenced to true north 000.0° to 359.9°
d9 Date (ddmmyy)
f10 Magnetic variation (degrees)
c11 Direction of magnetic variation:
• Easterly variation - subtract this value from true north
course
• Westerly variation - add this value to true north course
d12 Positioning system mode indicator
• A—Autonomous mode
• D—Differential mode
• E—Estimated (dead reckoning) mode
• M—Manual input mode
• S—Simulator mode
• N—Data not valid
The positioning system mode indicator field supplements
the positioning system for the Status field.
*hh The hexadecimal checksum is computed by exclusive -
ORing all of the bytes in the message between, but not
including, the $and the *. The result is *hh where h is a hex
character.
Typical RMC message:
$GPRMC,213357.20,A,3722.410857,N,12159.773686,W,000.3,102.4,290
498,15.4,W*43
NMEA Commands
Table 8.42. $GPRMC Message Format
Description Range
000000.00 to 235959.95
A, D, V
0000.000000° to
8959.999999°
N—North
S—South
00000.000000° to
17959.999999°
E—East
W—West
000.0 to 999.9
010100 to 123199
0.0° to 99.9°
E—East
W—West
A, D, E, M, S, or N
0 to 9 and A through F
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