Standard NMEA: Course over ground and ground speed.
NMEA-GP-VTG_GNSS for combined (average) output from both receivers
The course over ground and speed over ground are computed from the average position and velocity between GNSS1 and GNSS2. Note that this is not the same as the average of the individual COG and SOG.
The positioning mode is from the “best” receiver
NMEA-GP-VTG_GNSS1 for output from GNSS 1 receiver
This is the standard NMEA VTG for GNSS1.
NMEA-GP-VTG_GNSS2 for output from GNSS 2 receiver
This is the standard NMEA VTG for GNSS2.
NMEA-GP-VTG_FUSION for output from Fusion
The course over ground and speed over ground are from fusion.
The positioning mode is from the “best” receiver
These messages donot contain any information that would let one tell them apart. Do not enable more than one of these in the same port.
This message is according to NMEA 0183 v4.11 (and erratas).
It uses the “GP” talker ID even though the navigation solution is multi-GNSS.
Normal:
$GPVTG,0.0,T,,M,0.0,N,0.0,K,D*08rn
With non-standard high-precision fields
$GPVTG,0.0000,T,,M,0.01316,N,0.02437,K,D*3Frn
| # | Field | Format | Unit | Nullable | Example | Description |
|---|---|---|---|---|---|---|
| 1 | cog_true |
|
deg |
Y |
|
Course over ground wrt. True North |
| 2 | cog_ref_t |
|
- |
Y |
|
COG reference, always |
| 3 | cog_mag |
|
- |
Y |
|
Course over ground w.r.t. Magnetic North, always null |
| 4 | cog_ref_m |
|
- |
Y |
|
COG reference, always |
| 5 | sog_knot |
|
knots |
Y |
|
Speed over ground in knots |
| 6 | sog_unit_n |
|
- |
Y |
|
SOG reference, always |
| 7 | sog_kph |
|
km/h |
Y |
|
Speed over ground in km/h |
| 8 | sog_unit_k |
|
- |
Y |
|
SOG reference, always |
| 9 | mode |
|
- |
N |
|
Positioning system mode indicator, |