UPF based autonomous navigation scheme for probe encountering small celestial body

On the basis of the optical navigation scheme with objective celestial body information, the encounter task is realized. The accuracies of orbit determination and ephemeris are improved by using navigation camera. On this basis, the Unscented Particle Filter (UPF) is introduced to the navigation scheme to overcome the shortcomings of large initial estimation errors and non-Gaussian distribution of the state or measurement errors that may exist in the determination of the deep space orbit. Taking the advantage of UPF in tackling nonlinear and non-Gaussian problems, the disadvantages in the approximate treatments of nonlinear and non-Gaussian state model and measurement model by traditional EKF, UKF and PF schemes are also gotten over. The feasibility of the proposed scheme is demonstrated by numerical simulations.