2020-11-29, 05:28 PM
opencpn will still display the calculated XTE regardless of how the autopilot is following the route, so you still have that information. No mode ever keeps xte = 0, but all logic attempts to reduce it.
Using my improved logic in the autopilot_route_pi of "route position bearing" the autopilot more closely follows the route and the XTE is closer to 0 than before near waypoints. In between waypoints far from routes, it still does better, unless you manually tune the xte correction turn (normally fixed) then the results are basically the same.
This is my frustration: they are using a sub optimal algorithm that has discontinuities near waypoints and then people assume it's a good way to do things because it's been around a long time. so XTE is always calculated, but should be for display purposes and possibly alarms but not actual autopilot corrections, because it does not look at turns coming up, it only considers the present position and right angles of it to the route.
Using my improved logic in the autopilot_route_pi of "route position bearing" the autopilot more closely follows the route and the XTE is closer to 0 than before near waypoints. In between waypoints far from routes, it still does better, unless you manually tune the xte correction turn (normally fixed) then the results are basically the same.
This is my frustration: they are using a sub optimal algorithm that has discontinuities near waypoints and then people assume it's a good way to do things because it's been around a long time. so XTE is always calculated, but should be for display purposes and possibly alarms but not actual autopilot corrections, because it does not look at turns coming up, it only considers the present position and right angles of it to the route.