I have tried to install the Lidar, but it wasn't really working. Also, they are quite big and heavy, and expensive. Around 200 USD is quite a lot.
My problem is this:
During long flights (mapping flights for example) with my quadplane, I noticed quite some barometer drift. Sometimes nothing, sometimes a lot. On my last flight it was actually 7 meters in the wrong direction. That means, the Pixhawk thought he was still 7 meters up in the air, but already on the ground.
That means, there was never a flare to slow down the descent rate which is set at 5 meters.
Fortunately I set the descent rate not too high, so the landing was still ok, a bit fast, but no damage done.
So my thinking is like this:
If I could use a simple, cheap ultrasonic device to initiate the final landing stage, it should already be ok. Most of them work in the range of 3 to 4 meters, which should be ok for starting the final, slow landing descent and also solve the problem of landing detection.
Do you have any idea if this is possible?