A Fast Complementary Filter for Avoiding the Magnetometer Measurements From Influencing the Calculation of Pitch and Roll

Despite the magnetometer in a magnetic and inertial measurement unit (MIMU) being used to estimate the azimuth, its measurements can also negatively affect the computation of inclination angles when magnetic disturbance appears. It is challenging to eliminate that negative effect. For problem-solving, a new complementary filter (CF) is proposed. The filter is divided into two stages. In the first stage, the attitude represented by quaternion is predicted by gyroscope, and then, the predicted quaternion is converted to Euler angles. In the second stage, the predicted Euler angles are compensated by employing the accelerometer and the magnetometer, and then, the after-compensated Euler angles are converted back to quaternion. To solve the problem of “gimbal lock,” two sets of Euler angles with different definitions of the rotation sequence are used. The simulation and experiment results demonstrate that the proposed filter outperforms six other competing filters, revealing its potential usage in such applications where magnetic disturbance is not allowed to affect the computation of inclination angles.