Calibration of Low-Cost Three Axis Magnetometer with Differential Evolution

The magnetometers are used in wide range of engineering applications. However, the accuracy of magnetometer readings is influenced by many factors such as sensor errors (scale factors, non-orthogonality, and offsets), and magnetic deviations (soft-iron and hardiron interference); therefore, the magnetic calibration of magnetometer is necessary before its use in specific applications. This research paper describes calibration method for three axis low-cost MEMS (Micro-Electro-Mechanical Systems) magnetometer. The calibration method uses differential evolution (DE) algorithm for the determination of the transformation matrix (scale factor, misalignment error, and soft iron interference) and bias offset (hard-iron interference). The performance of this method is analysed in experiment on three axis low-cost magnetometer LSM303DLHC and then compared to the traditional method (least square ellipsoid fitting method). The magnetometer readings were obtained while rotating the sensor around arbitrary rotations. The experimental results show that the calibration error is least using DE.