Height estimate unstable for hand-launched fixed-wing (Autonomous SITL simulation)

Hello everyone, I am trying to run an autonomous SITL simulation for a hand-launched fixed-wing using QGroundControl and SIMNET simulator (PX4 firmware version is v1.13).

The aircraft refuses to be armed as the height estimate is unstable and there is an error in baro. Below are my conclusions:

  • The aircraft is initially positioned at an altitude higher than ground in the simulator as it is hand-launched. Is this where the unstable height estimate issue arises from?
  • I tried setting the launching method as ‘from the ground’, and the issue didn’t show up.

I tried tweaking the parameters to make any parameters related to height difference and barometer less sensitive, and I also changed the take-off altitude parameter, but this didn’t change anything.

Any suggestions? I’d also be grateful to know any tips from experience related to conducting an autonomous SITL simulation for a fixed-wing.

Thank you.