Standard NMEA: True heading. This message contains the actual vessel heading (from the Fusion solution) in degrees. “True” means the geometric North (not the magnetic North). Note that this is not the heading of motion (direction of travel) but the orientation of the sensor.
Normal:
$GPHDT,61.7,T*05rn
With non-standard high-precision fields:
$GPHDT,61.7183,T*3Frn
| # | Field | Format | Unit | Nullable | Example | Description |
|---|---|---|---|---|---|---|
| 1 | heading |
|
deg |
Y |
|
True heading |
| 2 | true_ind |
|
- |
Y |
|
Always |
It uses the “GP” talker ID even though the navigation solution is multi-GNSS.