During an indoor flight test, I observed a potentially critical issue with altitude control using an MTF01 Micro Air Optical Flow sensor. I configured the system to perform a controlled takeoff via QGroundControl with a MIS_TAKEOFF_ALT set to 0.7m, but the drone continued to ascend beyond that and h…

Your log shows you armed in position control mode and then you switched to takeoff mode, not mission mode. As QGC let’s you select the takeoff altitude, this will override the MIS_TAKEOFF_ALT, what did you select?

Upon further inspection of the vehicle_command messages, the takeoff request that arrived from qgc had altitude set to 702m.

Thanks @Benja I didn’t use Mission mode. I used the Takeoff button from the QGroundControl home screen (top-left corner). I didn’t explicitly set any altitude there . Also, can you please confirm if PX4 actually used the MTF01 MicroAir’s optical flow and rangefinder (LiDAR) data for altitude and p…

[image] anuj_yadav: I used the Takeoff button from the QGroundControl home screen (top-left corner). I didn’t explicitly set any altitude there . Could you (without taking off) check what’s the default altitude it sets there? It’ s to confirm that a reasonable value was set there (10m for exa…

I am thinking of trying to fly the drone in position mode , so i can check if the optical flow is working ,or I will just plan a mission to takeoff (small altitude ) and then land . @Benja thank you for your valuable advice, what do you think about this plan ?

Disable GPS in EKF (EKF2_GPS_CTRL = 0) and fly position mode, you won’t even be able to arm if the OF does not work properly. As an intermediate step, fly altitude mode (so the position is not used for control) and the check the log to see if the estimated local position matched the movement you di…

Thanks a lot @Benja I will try this .

Drone Hits Ceiling: MIS_TAKEOFF_ALT Not Respected with EKF2_HGT_REF = Range Sensor

PX4 Autopilot

Benja July 5, 2025, 9:46pm 2

Hey @anuj_yadav , do you still have the mission file you loaded?

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Drone Hits Ceiling: MIS_TAKEOFF_ALT Not Respected with EKF2_HGT_REF = Range Sensor

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