A MEMS inertial sensor and AMR magnetic sensor calibration method

Low cost inertial/magnetic sensors are typically used for AHRS (attitude and heading reference systems) to determine sensor attitudes in navigation systems. Sensor calibration procedures are very critical to achieve precise attitude reconstruction. This paper is focused on calibration of errors caused by sensors deviations from drift, sensitivity, non-orthogonal directions and misalign of magnetometer and accelerometer as well as the drift of gyroscope sensors. The proposed calibration methods utilize the fact that the norm of the measured output of the accelerometer and magnetometer is nearly constant in the stationary field, space rotation angle of cross product by accelerometer and magnetometer, and the gyroscope drift is correlated with the acceleration. The experimental results demonstrate that the output signal can be corrected by the proposed method. The norm errors of accelerometers and magnetometers wave is reduced from ± 15% down to ± 2% by calibration, the static rotation angle accuracy is not more than 1° by accelerometers and magnetometers, and the rotation angle accuracy is not more than 2° in one minute by the calibrated gyroscope.