Micro AHRS algorithm based on three-component geomagneticfiltering technology

ZHAO Yan-ming，CHANG Hong-long，YUAN Guang-min，SUN Xiong-fei

（Key Laboratory of Micro/Nano Systems for Aerospace，Nothwestern Polytechnical University，Xi'an 710072 China）

Abstract： Aiming at overload interference and filtering divergence of common micro attitude heading reference system（AHRS）algorithms，a micro AHRS algorithm based on three-component geomagnetic filtering was proposed，which adopted a simplified Sage-Husa adaptive filter. Then，attitude errors and gyros's drifts were chosen as the states of the AHRS system，and the three-component geomagnetic vector from three-axis magnetometer was taken to construct the measurements. The adaptive filtering was used to estimate errors of AHRS. Finally，AHRS semi-physical simulation was done. Simulation results show that，this algorithm can reduce the overload interference effectively. Under the testing condition of 2 g random vibration，attitude errors are less than 0.75°，heading error is less than 1.87°，the system measurement precision is improved almost by 3.2 times. The new algorithm improves the accuracy，anti-overload property and adaptability. This algorithm is particularly suitabler for the work environment with low ferromagnetic interference and high overload.

Key words：micro attitude heading reference system（AHRS） ；three-component geomagnetic vector；Sage-Husa adaptive filtering；anti-overload property；adaptability