Geomagnetism GPS SINS Integrated Navigation Based on an Improved Square-Root UKF

According to the peculiarity of the system model, the Square-root UKF algorithm is improved. Compared with Square-root UKF, the improved Square-root UKF reduces the computational complexity, under the premise of guaranteeing the positive semi-definiteness of the state covariance. To improve the performance of navigation system when the attitude errors are large, a nonlinear attitude errors measurement equation of geomagnetism is derived, and a new nonlinear algorithm for geomagnetism/GPS/SINS integrated navigation is proposed based on the improved Square-root UKF. The simulation results show that the effect of attitude errors of correction is enhanced through introducing the information of attitude errors of geomagnetism into navigation system in the case of system with large attitude errors. It can be concluded that the nonlinear geomagnetism/GPS/SINS integrated navigation system can improve the performance of navigation.