QGC & PX4 Multi Vehicle SITL - Vehicle did not respond

Dear all, I’m using the multi vehicle SITL with a custom dynamics and sensor model in Unity 3D. With a single px4 instance, everything works just fine.
When using the multi_vehicle simulation data from PX4 to QGC is also received as expected. However, commands from QGC to the PX4 instances are regularily not recognized and QGC shows “vehicle did not respond”. My specs:

  • PX4 1.13.3 on [Ubuntu 22.04 Parallels VM on Windows, Ubuntu 22.04 in a Docker Image on Windows & Mac M1]
  • QGC 4.2.6 on [Windows, Mac M1] with mavlink-router

Did anyone experience similar things with the multi vehicle simulation or has an idea? I’d highly appreciate it! Best regards, Mats

The low level udp communication is not that reliable in the multi vehicle case, you may try to switch to the tcp method, and reduce the message rate where necessary.

All the best.

Thank you so much for the fast response. How would I switch to TCP within PX4? Is there any parameter that needs to be exported prior to the launch? In px4-rc.mavlink, the streams are started with the MAVLink command. However it’s description says “This module implements the MAVLink protocol, which can be used on a Serial link or UDP network connect”, where they don’t mention TCP. How would you then receive the aircraft state and send commands as you would do over UDP?