Gives a desired position, heading, yaw rate and speed for a path of straight segments between waypoints, with a circle arc at each inner waypoint. A state, TrackState, is the distance travelled along the path: its rate is the vessel velocity (horizontal) projected on the direction of the path. The desired values are for the point on the path a distance Lookahead ahead of that distance. On a straight segment the speed is the speed of that segment; on an arc it is a blend of the speeds of the straight segments before and after. The waypoints are in the horizontal plane (the down coordinate is 0). The input arrays have N waypoints, at least 2.
Input ports
| Name | Width | Description |
| PositionNED | 3 | Position of the vessel in the NED frame |
| VelocityNED | 3 | Velocity of the vessel in the NED frame (the horizontal part is used) |
Output ports
| Name | Width | Description |
| DesiredSurgeBody | 1 | Desired speed (see StraightSegmentU) |
| DesiredYawNED | 1 | Desired heading |
| DesiredYawRateNED | 1 | Desired yaw rate: 0 on a straight segment, and the speed of the vessel along the path divided by the radius on an arc (positive to starboard) |
| DesiredPosition | 3 | Desired position on the path |
Configuration parameters
| Name | Width | Description |
| WaypointN | N | North coordinates of the waypoints. Required. Its size sets N |
| WaypointE | N | East coordinates of the waypoints. Required |
| WaypointR | N | Distance before and after an inner waypoint where the arc starts and ends. Required |
| StraightSegmentU | N-1 | Speed on each straight segment. Required |
| Lookahead | 1 | Distance along the path from the position of the vessel to the desired point. Default 0. Unit not stated in the code |
| TrackColor | 3 | Colour of the path, RGB. Default 1, 0, 0. Builds with visualization only |
| RemovedColor | 3 | Colour of the removed corners, RGB. Default about 0.33, 0.33, 0.33. Builds with visualization only |
| SectorColor | 3 | Colour of the arc sectors, RGB. Default about 0.46, 0.46, 0.46. Builds with visualization only |
| SightColor | 3 | Colour of the line of sight, RGB. Default 0, 0, 1. Builds with visualization only |
States
| Name | Width | Description |
| TrackState | 1 | Distance along the path. Initial value: the projection of the initial position on the straight line of the leg that the code picks from the closest waypoint, not below 0 |
Collaboration diagram for Waypoint reference tracker:
1.9.8