Hi B,Some gps devices aquire ephemeris files giving information on positions of satellites. I’m not going to try to explain it, but yes, the orbits and positions of the gps satellites can be predicted.
But, the drone altitude is calculated by the drone’s barometer and is never going to be absolutely accurate or even stable, given that atmospheric pressure changes over time as well as due to altitude change. Hence me having to recalibrate my watch before exercise and it not being able to accurately tell me how many flights of stairs I’ve climbed!
Ok, thanks, as I'm on the wrong thread, I'll ask again in a separate one.
C.