ZyCast
SG-289 User’s Manual v1.1
22
$GPVTG
This message transfers velocity, course over ground, and ground speed. Following is an example.
$GPVTG,309.62,T, ,M,0.13,N,0.2,K,A*23
The $GPVTG message format is shown below.
Field Example
Unit
Notes
Message ID
$GPVTG
VTG protocol header.
Course (true)
309.62
degree
Measured heading
Reference
T
T = true heading
Course (magnetic)
degree
Measured heading
Reference
(1)
M
M = magnetic heading
(1)
Speed
0.13
knot
Speed in knots
Units
N
N = knots
Speed 0.2
km/hr
Speed
Units
K
K = km/hour.
Mode
(2)
A
A=Autonomous, D=DGPS, E=DR.
Checksum *23
<CR> <LF>
Message terminator.
(1) SiRF does not support magnetic declination. All “course over ground” data are geodetic WGS84 directions.
(2)
Fields marked in italic red apply only to NMEA version 2.3 (and later) in this NMEA message description.
