A novel in-motion initial alignment method for SINS assisted by DVL

The in-motion initial alignment of the strapdown inertial navigation system (SINS) assisted by the Doppler Velocity Log (DVL) plays a significant role in the efficient operation of the autonomous underwater vehicle (AUV). In the case of severe maneuvering or low accuracy of inertial sensors, the output error of the gyroscope gradually increases, which leads to a decrease in the initial alignment accuracy of the inertial navigation system. In this paper, an in-motion alignment method for DVL-assisted SINS is proposed, which eliminates the effect of attitude matrix variations on the observation noise by establishing an accurate filtering model for the constructed inertial vectors. Experimental results verify that the proposed algorithm can accurately estimate the attitude matrix, and the initial alignment accuracy is improved as compared with existing algorithms.