Magnetometer bias calibration based on relative angular position: Theory and experimental comparative evaluation

This paper reports on a novel method for estimating the sensor bias of three-axis magnetometers (or any other field sensor). Our approach employs relative angular position measurements to estimate the three-axis magnetometer measurement bias, significantly improving magnetometer-based attitude estimation. Relative angular position measurements can be calculated from a variety of sources, including multiview image registration or laser-based scan matching. We report two methods implementing this approach based on batch linear least squares and a real-time discrete Kalman filter. Compared with previously reported methods our approach is time independent and less restrictive with data sampling. In addition, our two methods (i) are empirically shown to impose less restrictive conditions for the movements of the instrument required for calibration, (ii) do not require knowledge of the direction of the field (e.g., the local magnetic field) or the attitude of the instrument, and (iii) also ensure convergence for the estimated parameters. The proposed methods are evaluated and compared with previously reported methods in both numerical simulation and in comparative experimental evaluation using cameras and magnetometer sensors under different conditions.