Hello everyone!
I’m trying to use optical flow sensor on my small racing quad, to be have stable hover and failsafe landing indoors and outdoors, without any GPS module installed.
I’m using UPFlow sensor and micro lidar from Aliexpress (senses up to 30 meters). After setup and tune, my quad hovers in optical Loiter (using EKF3) absolutely stable at low heights indoors and outdoors, even in wind. But only at heights up to 10 meters.
When I’m trying to hover at 15-20 meters, after 10 seconds quad starts to wobble in pitch/roll more and more, totally losing control. I’m saving it only by switching to stabilize mode and land manually. Lidar measurements is absolutely stable at this height, so can’t cause problems.
I tried to adjust some optical flow related EK3 parameters, but not successed 
Currently I have 4.2.0 software on my quad.
Can it be sensor sensitivity limit? Or I can adjust behavior somehow?
Thank you!