Hi,

I made a plugin for XPlane, so i can simulate my UAV code before i buy/make any hardware. Stabilisation, "pathfinding" works great but Im stuck with my AHRS. I implemented a basic Kalman Filter, which works great so far for estimating roll and yaw with gyros, accelerometers and GPS. 

However pich gives me some trouble. Altough William Premerlani wrote in his DCMDraft2 (page 24) that the forward Acceleration doesn't distort the result alot, it is the source of all my problems. 

I tried to correct it, by using the difference in airspeed. It worked somewhat, but I'm not sure how well this will work in reality.

What should i do to get the best result?
How much does the forward acceleration do in reality?

regards
Philipp