Raymarine forum

Full Version: Minimum data requirements for a Raymarine autopilot to enter Track mode
You're currently viewing a stripped down version of our content. View the full version with proper formatting.
Minimum data requirements for a Raymarine autopilot to enter Track mode

When properly interfaced to a GPS display or chartplotting product (ex. Multifunction Display (MFD), chartplotter, GPS/Chartplotter, or computer running a charplotting application) and the device has been commanded to go to a waypoint / cursor position or to follow a route, Raymarine autopilots may be commanded into Track mode. When operating in track mode the autopilot will attempt to a) steer the vessel to the waypoint / cursor position specified by the GPS or chartplotting product while b) keeping the vessel within a corridor surrounding the course line whose width is determined by the response / performance setting which the operator has configured within the autopilots.

When addressing the subject of this FAQ, it is best to list the minimum data that Raymarine autopilots require in order to track, rather than a list of NMEA 0183 sentences or NMEA 2000 PGNs which must be transmitted to the autopilot. That said, the RMB NMEA 0183 sentence is usually the best choice for supporting the autopilot’s Track feature when using autopilot designs preceding Raymarine's Evolution autopilots. The minimum list of data that a Raymarine autopilot requires to track follows:

BTW = Bearing to Waypoint
DTW = Distance to Waypoint
WPID = Waypoint ID (AKA = waypoint number)
XTE = Cross Track Error

Additional Note: Any Bearings need to be magnetic (preferred); otherwise, the autopilot must receive true bearings with variation in order to permit the autopilot convert the true bearings to magnetic bearings.

The RMB NMEA 0183 sentence contains BTW, DTW, WPID and XTE all in one sentence. As such, the autopilot will support tracking when this single NMEA 0183 sentence is received, as long as the included bearings are Magnetic as indicated above.

Reference URL's