探测器交会小天体的UPF自主导航方案

UPF based autonomous navigation scheme for probe encountering small celestial body

采用基于目标天体信息的光学导航方案实现探测器交会小天体,利用导航相机提高了定轨精度和星历精度。在此基础上,针对深空导航的轨道确定过程中可能存在的初始估计信息误差较大、状态及量测误差不服从高斯分布等问题,将UPF(Unscented Particle Filter)引入到导航方案中。该方案利用UPF在处理非线性非高斯问题上的优势,克服了EKF、UKF、PF等传统滤波方案对非线性非高斯状态模型、量测模型的近似处理所带来的影响。数值仿真表明了该方案的可行性。

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.