Doppler Velocity of the Sun/Star (DVS)-Aided SINS Integrated Navigation Method

The strap-down inertial navigation system (SINS)/ celestial navigation system (CNS) integrated navigation is a widely used autonomous navigation for spacecraft. However, the traditional SINS/CNS integrated navigation cannot correct the velocity error directly, which is vital for improving navigation accuracy. The Doppler velocity of the Sun/star (DVS) is an autonomous way to provide accurate velocity information. Thus, to correct the velocity error of the SINS, a DVS-aided SINS integrated navigation method is explored in this study, where the Doppler velocities of the Sun and two stars are used as measurements. The measurement and measurement model of DVS is derived, and the system framework of the DVS-aided SINS integrated navigation method is established. To verify the effectiveness of the DVS-aided SINS integrated navigation method, the performance of the SINS and the DVS-aided SINS integrated navigation method are compared. The simulations show that for the spacecraft whose horizontal flight path angle is 25^◦ and azimuth is 90^◦, the position errors in longitude, latitude, and height of the newly proposed method are only 10%, 20%, and 11%, respectively, of that of the SINS. The velocity errors of the newly proposed method in east, north, and upward are only 7%, 2%, and 9%, respectively, of that of the SINS. In addition, the impact of the measurement error of DVS, the number of stars observed, and different stars observed are evaluated by simulations.