On Calibration of the Magnetometer with the Help of the Gyroscope

The paper presents a method to calibrate the magnetometer. In practice the magnetometer is manufactured in the same chip among the gyroscope and the accelerometer. The magnetometer measures the magnetic field of the Earth. It is known that magnetic field has two parameters having values depending on the location on the Earth. These parameters are the magnitude and the angle to the horizon. It is presented a solution to rotate the magnetometer until its tri-dimensional output has a precise dependence to the two parameters of the magnetic field. This output is retained as a reference value. Then the magnetometer measurement is computed according to rotation matrix and this reference value. Rotation matrix depends on the gyroscope output. In this way, the magnetometer calibration is made simpler than the literature methods. The proposed method also eliminates soft iron and hard iron distortions because the gyroscope is not affected by such errors. Experimental results that confirms the proposed method, that are tested for two different sensors are presented.