No fall trough to Baro if GNSS disappears

[MikeRogerIt]

I recently had a flight with my fw drone using px4 v1.16.0 with a pixhawk 6X on the jetson board. When satellites dropped to 0 all altitude values and climb rate were shown as a.n. which made the fc switch to land mode. Looking at the code PX4-Autopilot/src/modules/ekf2/EKF/height_control.cpp at 6e418096b72de4a7817757220b0c2b1bd55195a9 · PX4/PX4-Autopilot · GitHub I expected the fc to switch to baro for altitude continuing the flight without issues but that didn’t happened. I later tried the same in gazebo SITL and as expected from the code after setting sim sat to 0 altitude values all were displayed and just disappeared showing a.n. when I disabled the baro too.

Can anyone tell me if that’s normal that there is such a different behavior between SITL and real flight in that case or how to solve this for a real flight? If I remember correctly this fall trough was working in prior versions without any issue.

In both cases ekf2_hgt_ref was set to GNSS

[Dr.Gadget]

It you lose GNSS (global/local position) you will be demoted to altitude and then stabalized.

Send the log file (upload to flight review) and I can check your parameters.
You probably don’t have baro activated

[MikeRogerIt]

Thanks for your help. I don’t have a log unfortunately but here is a screenshot of the baro parameters set for that flight. As you can see baro is activated (default setting).