Magnetometer calibration algorithm based on ellipsoid constraint

Calibration of magnetometer is an essential part to obtain high measurement precision. However, the existing calibration methods are basically the calibration of all attitudes, which means tough work when the magnetometer is applied in strapdown inertial navigation system (SINS). So a quick, easy and effective calibration algorithm is developed based on the ellipsoid constraint to calibrate magnetometers. In this paper, the measuring principle and error characteristic of the magnetometer are analysed to study its magnetic interference. During the process, a magnetometer calibration model is set up to convert the calibration to ellipsoid fitting based on the characteristic of hard magnetic interference and soft magnetic interference. Then the algorithm is tested by mimic experiment. The result shows that measurement precision is improved after the calibration, and then the magnetometer is installed in a control cabin of an underwater robot which is designed and developed by us, and actual magnetometer calibration experiments are conducted to further verify the validity of the algorithm.