"Bill, thank you. As i understand this effect is present but on the small scale and scale will be very dependent on how accurately actual sensor noise variance setup in the filter. Thanks for sharing you very non-trival code!"

"Hi Bill, i noticed that you including accelerometer biases in your KF. Wonder what happens when quad-rotor hovers for prolonged time in steady wind. Since GPS position is not changing it should slowly leak into accelerometer bias. Which should lead…"