So I noticed that the vertical velocity as returned by GetGroundspeedVector(FRAME_HORIZON) is subject to the terrain the vehicle is flying over, so when flying over rugged terrain it jumps quite a bit. (Let's call this "relative velocity", VR.)
If I get the vertical component (stright to the center of the Earth) of the velocity of the vehicle in relation to the center of the Earth (and this would be "inertial velocity", VI), could I use it to "replace" the vertical component returned by GetGroundspeedVector?
I think the rotation of the Earth doesn't "contaminate" the vertical component of VI, so that should be "pure", and in VR, the horizontal components should not be affected by the terrain below, so it seems a fair match... :shrug:
... or is there a more direct/better/correct way to get a "clean" vertical velocity?