Ardurover does not send NAV_CONTROLLER_OUTPUT message, and can't seem to request it from Pymavlink

I am currently working on a companion computer that mounts to my rover and gets messages from the rover to record on its own storage drive alongside sensor readings.

Working with Arduplane, I am able to get most messages, but as soon as I switched to Rover I am unable to get the NAV_CONTROLLER_OUTPUT messages from mavlink. It is the same request message, nothing has changed.

What I don’t understand is I know that mission planner sees those same messages as I can watch the x-track error. However even looking at the Mavlink Inspector I can not see where it is getting that message from.

Start by reproducing the NAV_CONTROLLER_OUTPUT request with pymavlink against Rover rather than Plane. Compare the messages visible to the companion computer with those shown in Mission Planner and the MAVLink Inspector; done means identifying whether Rover emits the message and whether pymavlink can receive it.

Written by the indexing model from the issue text.