I am trying to replace the in-built SITL physics simulation with a custom one written in Unity (with ArduPlane in mind), but I’m finding it to be quite difficult so far.
I found no specific documentation regarding the MAVlink messages passed between the SITL applications and the simulation.
From what I understand, the entire sim_vehicle.py launch sequence compiles and launches several applications via new terminals with a number of passed arguments. Which makes it harder to pin-point what I need to modify to make it work.
Also, it feels like the documentation is outdated since I saw no packets sent at ports 5501 and 5502 when running the SITL. That being said, for some reason, sending dummy packets to 5501 does confuse the simulation somehow.
All in all I would appreciate any help, guide-lines or tips on how to tackle this task.