Inertia Moments - IMU Pixhawk


I have a problem and maybe you can help me. I wanted to calculate the inertia moments of a VTOL and did a bifilar pendulum test. I logged the IMU data from the pixhawk (gyroscope data) and I tracked the angular velocity with a camera tracker and we stopped time and counted the oszillations to have some data for sanity check. In the end the hand measured data and the camera tracker offered very similar data and in y axis (body fixed frame) the IMU had an offset of over 20% and in z-axis around 10%. The x axis was very similar. We thought maybe the offset to the rotational axis of the pixhawk has an impact, because the x axis is the only one were the pixhawk lies approximatly in the rotational axis. But for angular velocity there should be no difference. Does anyone no what the issue could be? Maybe some calculations were made in ardupilot?
Thank you so much for helping!!! :slight_smile: