Why network heading matters
Radar, charting and autopilot functions must share a consistent heading source. Competing sources or a slow primary source can cause display differences and delayed reactions.
Key PGNs
| PGN | Data | Typical consumer |
|---|---|---|
| 127250 | Vessel Heading | Radar, autopilot and heading display |
| 127251 | Rate of Turn | Steering and manoeuvre monitoring |
| 127252 | Heave | Vertical motion compensation |
| 127257 | Attitude | Roll and pitch |
| 129025 | Position Rapid | Fast position display |
| 129026 | COG/SOG | Ground track and speed |
| 129029 | GNSS Position | Complete GNSS solution and quality |
Prevent source conflicts
- Open the source-selection page on each display.
- Select GeoX for the data it must provide.
- Check heading consistency at rest and through a turn.
- Confirm that the selected output rates do not overload the bus.
Calculation and publication rates
The inertial solution may be calculated far faster than messages are placed on the marine network. The internal rate supports the estimator; the publication rate must match the consumers and available bus bandwidth.