Zero-crossing method for hard iron interference and zero drift compensation applied to magnetometers

This paper presents a zero-crossing method for two-axis magnetometers that compensates the measurement offsets when sensor outputs are distorted due to the time-varying hard-iron interference and zero drift effects. The compensation method is derived based on a Kalman filter which can be used for real-time estimation. The performance of proposed method is evaluated using HMR2300r magnetometer with a ferromagnetic turntable. The angle estimation error after compensation was on the order of 1 to 2 degrees.