Magnetometer calibration using inertial sensors
This work addresses magnetometer calibration for orientation estimation in sensor units, but it is incremental as it builds on existing methods for sensor fusion.
The authors tackled the problem of calibrating magnetometers for magnetic disturbances and sensor errors, presenting an offline maximum likelihood algorithm that corrects misalignment with inertial sensors, leading to significantly improved heading estimates in orientation estimation.
In this work we present a practical algorithm for calibrating a magnetometer for the presence of magnetic disturbances and for magnetometer sensor errors. To allow for combining the magnetometer measurements with inertial measurements for orientation estimation, the algorithm also corrects for misalignment between the magnetometer and the inertial sensor axes. The calibration algorithm is formulated as the solution to a maximum likelihood problem and the computations are performed offline. The algorithm is shown to give good results using data from two different commercially available sensor units. Using the calibrated magnetometer measurements in combination with the inertial sensors to determine the sensor's orientation is shown to lead to significantly improved heading estimates.