AP_DDS: Set Altitude and Climbrate command through ROS2/DDS interface

[PQuill33]

I would like to give some external control capability to plane to be able to command its altitude and/or climbrate through the ROS2/DDS interface.

Problem
Looking for a path forward here. I think I can make an external control interface that subscribes to a topic (i.e. /ap/alt_climbrate) based on the global position command message and only parse out the altitude and z-velocity components. Then I would use those to adjust the airspeed (AIRSPEED_CRUISE) and send an altitude target for the plane to reach. The combination of those two actions I think could achieve the desired result.

I would think that using the whole global position message for this would be wasteful and would look for a more appropriate option or make a custom one if that's the case.

Platform
[ ] All
[ ] AntennaTracker
[ ] Copter
[ x ] Plane
[ ] Rover
[ ] Submarine