I am trying to understand this IMU calibration video.
In the video the operator gets accelerometer data when pointing each axis in the gravity direction. He then has an algorithm at minute 6:34.
I don't know where this algorithm comes from.
My understanding of how you get an accelerometer bias is you add the output when an axis is pointing in the gravity direction to the output when that axis is pointing antiparallel to gravity and then you divide by 2. Where is he getting this algorithm?