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Set a destination

Make the simulator steer for a waypoint so that the autopilot sentences APB, RMB and XTE and the Signal K course paths describe the leg towards it. The sentences are listed on the sentence reference and the geometry is explained in the simulation model.

The vessel does not turn towards the destination by itself: steer it with the keyboard or sail a track, and watch the cross-track error change.

On the map

Hold Shift and click the spot on the map, or right-click it and choose Set destination here. A magenta diamond marks the waypoint, a dashed line shows the bearing from the vessel and the Destination tile on the dashboard shows the bearing, the distance and the cross-track error with the side to steer. The leg starts where the vessel was at that moment, so the cross-track error is zero until the vessel leaves the line.

Simulation → Clear destination, or the same entry in the map's right-click menu, stops the autopilot sentences.

The waypoint is named WPT. To rename it, or to type coordinates, open File → Settings... and use the Destination group of the Simulation tab, which also sets the arrival circle radius (100 m by default). Save the profile to keep the destination.

From the command line

nmeasim run --tcp-server 10110 --destination 37.7466,23.4275,AEGINA

The leg starts at the profile's initial position. A profile carries the same information in simulation.seed.destination (reference):

"destination": { "name": "AEGINA", "latitude": 37.7466, "longitude": 23.4275,
                 "origin_latitude": 38.0, "origin_longitude": 23.7, "arrival_radius_m": 100 }

What the consumer sees

  • APB carries the cross-track error, the bearing of the leg and the bearing to the waypoint, and flags the arrival circle and the perpendicular at the waypoint.
  • RMB adds the waypoint position, the range and the closing velocity.
  • XTE carries the cross-track error alone.
  • Signal K outputs publish navigation.courseRhumbline.*, including nextPoint.position, nextPoint.distance and crossTrackError.

OpenCPN shows the waypoint and the cross-track error on its dashboard instruments when an autopilot sentence arrives; a Signal K server shows the course paths in its data browser.