Autonomous optical navigation for cislunar spacecraft based on earth-moon information

The autonomous optical navigation algorithm based on Earth-Moon information during the cislunar transfer orbit phase is presented. In the algorithm, first, the image elements of Earth and Moon centers are obtained by processing the images of Earth and Moon. Then, these image elements in combination with the inertial attitude of spacecraft, and the ephemeris of Earth and Moon at the time of the observation are used to determine the orbit by using the recursive weighted least square based on UD factorization. On the side, the observability degree definition of navigation system has been introduced and applied to the observability analysis of navigation system. And the autonomous optical navigation algorithm is validated using the numerical simulation.