一种基于小波-UPF的探测器自主光学导航方法

Spacecraft autonomous optical navigation based on the wavelet-UPF

提出了一种用于探测器在巡航段的自主光学导航方案,该方案利用光学导航相机以及星敏感器,通过测量星光信息以及天体边缘的信息,得出了探测器的相对位置。并利用小波分析对观测信息进行了预处理,滤除了它所包含的高频噪声,然后再进行小波重构得到平稳的观测信息,在此基础上进行'UPF(unscented particlefilter)滤波计算,以更好地降低重要性权值的方差,由此实时确定了探测器的轨道。该方法将小波分析和UPF滤波有机结合起来,可更好地提高自主导航系统的准确度和可靠性。通过数学仿真表明,改进的算法与原UPF算法相比,收敛速度更快,滤波精度更高。

An autonomous optical navigation scheme for cruise phase is presented, which uses the star light data and body edge data that are measured by star sensors and optical navigation camerae. And the relative posi- tion for probes is acquired from the star light data and body edge data. The observation information is pretreated by wavelet analysis and the high frequency noise is filetered. After that, the signal is recompased by wavelet a- nalysis to gain the smooth parameters value, and a process of UPF（Unscented Particle Filter） is made on these basis, so as to reduce the variance of importance weights. The real time orbit for probes is determined from this. The arithmetic integrates the wavelet analysis and UPF to improve the precise and reliability of the autono- mous optical navigation system. Simulation result shows that the improved UPF algorithm is not only more accurate but also quicker in the rate of convergence compared with the UPF.