IMU Orientation Calibration
Goal
Align all IMUs to a common board/rocket frame to correct for mounting misalignment.
Procedure (Sketch)
Use a machined square baseplate with orthogonal faces.
Mount the board and sensors carefully.
Place the assembly on a precisely horizontal table.
Collect accel data with low-pass filtering; when flat, only the vertical axis should read ~9.81 m/s²; others ~0.
Repeat for all orthogonal faces.
Compute per-sensor rotation matrices.
Store calibration constants in on-board flash and archive externally.
Recalibrate whenever sensors/board are moved or replaced.