Reference Information
LD900 Installation and Oper ations M anual
72
6.4.10 RMC Sentence
The NMEA RMC sentence provides essential GPS PVT (position, velocity, time) data.
RMC Sentence Structure & Example
$GNRMC, hhmmss.ss, a, ddmm.mmmmmmm, b, dddmm.mmmmmmm, c, dd.ddd, eee.e, ddmmyy f .f, g, h *hh
$GNRMC,
143909, A,
5107.0020216, N,
11402.3294835, W, 0.036, 348.3, 210307, 0.0, E, D *31
RMC Sentence Defined
Field
Content
RMC
Recommended Minimum Sentence C
hhmmss.ss
UTC time of position
a
Position status (A = Active V = Void)
ddmm.mmmmmmm
Latitude of position
b
Latitude direction (N or S)
dddmm.mmmmmmm
Longitude of position
c
Longitude direction (E or W)
dd.ddd
Speed over the ground , knots
eee.e
Course over ground, degrees True
ddmmyy
Current date
fff.f
Magnetic variation, degrees
g
Magnetic variation direction E/W
Easterly variation (E) subtracts from True course.
Westerly variation (W) add to True course.
h
Mode indicator (A = Autonomous, D = Differential, E = Estimated (dead
reckoning), M = Manual input, N = Data not valid)
*hh
Checksum
6.4.11 HDT Sentence
The NMEA HDT sentence provides heading information derived from the receiver.
HDT Sentence Structure & Example
$GNHDT, dd.dddd, T hh
$GNHDT, 75.5664, T *36
HDT Sentence Defined
Field
Content
HDT
Heading (true) message
dd.dddd
Heading in degrees
T
Degrees True
*hh
Checksum
