Analysis of Attitude and Heading Computer System in Magnetic Disturbance State

Abstract

AHRS (Attitude and Heading Reference System) has low attitude accuracy under magnetic disturbance. Because of this, this paper designs an extended Kalman filter-based attitude and heading reference system in a magnetic disturbance state. In general, the AHRS system only uses the Kalman filter and has low attitude accuracy under magnetic disturbance. The AHRS system designed herein first calibrates the distorted magnetic field value under magnetic disturbance by using the ellipsoid fitting algorithm to improve the heading angle accuracy. After that, the data from the magnetometer, accelerometer, and gyroscope are combined using the extended Kalman filter technique. An adaptive measurement noise covariance matrix is created to lessen the influence of carrier vibration and external magnetic disturbance on attitude measurement, which enhances the system’s anti-interference ability and improves attitude measurement accuracy. Experiments show that the system can not only properly use the gyroscope’s drift but also improve the accuracy in attitude estimation, with the root mean square error of the three angles above 0.5°.