Calibration of 3-axis Magnetometers

Calibration of all 3 axes of a 3D magnetometer in cases where the true field strength is unknown involves an elaborate test set-up and rotation of the unit about all three axes so as to cover a sphere/ellipsoid. This paper presents an alternate method for calibrating all three axis of a magnetometer, i.e. estimating bias and scale factors for all axes, using a simpler 2 step procedure. The proposed technique exploits the relation between the body axis rates and the Euler angles to define a limited rotation and an associated optimization problem to determine the calibration parameters.