Spacecraft Autonomous Navigation Using the Doppler Velocity Differences of Different Points on the Solar Disk

The solar differential rotation results in different velocities on the solar disk. The Doppler velocities of different points on the solar disk observed by the spacecraft are also different, which are functions of the current position of the spacecraft. Thus, using the velocities' information or their differences, the position of the spacecraft can be estimated. The advantage of velocity difference measurement is that the influence of some systematic error, such as the spectrometer error and the periodic variation of the sun's velocity on the navigation performance, can be eliminated. In this article, a new autonomous navigation method using the Doppler velocity differences of different points on the solar disk is proposed. Taking solar explorer as an example, simulations show that the proposed method can effectively restrain systematic errors compared with the traditional Doppler velocity method.