An initial alignment algorithm of strapdown inertial navigation system assisted by Doppler radar based on adaptive filtering

Abstract

In order to realize the autonomous initial alignment of the vehicle-borne strapdown inertial navigation system (SINS) on the moving base, an adaptive filter based initial alignment algorithm for Doppler radar-assisted SINS is proposed. The error analysis and modeling about Doppler radar and SINS are carried out, and the alignment state variables are selected according to the established error model. The measurement equation is established by using output of Doppler radar and SINS. The initial alignment algorithm is designed based on adaptive filtering. The simulation results show that the azimuth angle alignment accuracy of the method is better than 3', and the horizontal angle alignment accuracy is better than 1' in 220 s. The initial alignment can be completed quickly and accurately in the case of large Doppler radar velocity variance.