深空天文测速自主导航速度矢量合成误差传递分析

针对深空天文测速自主导航系统速度矢量合成过程中的误差传递问题,推导了视向速度测量误差与定速误差统计特性之间的映射关系,获得了当测量误差满足零均值高斯分布时的定速误差概率密度函数,给出了在特定条件下定速误差均值与方差的解析表达式。理论与仿真分析均表明,当三个恒星视线方向两两正交时,测量误差对定速误差的影响达到最小,仿真结果还给出了目标恒星夹角对误差传递的影响,这些研究结果可为测速导航系统的目标选取提供理论依据。

Analysis on error propagation in velocity vector synthesis of deep-space celestial autonomous navigation based on radial velocity measurement

According to the spatial geometrical relations of velocity measurement navigation principle,the determination of the spacecraft's velocity vector in inertial space requires measuring at least three stars' radial velocities.In view of the error propagation problem due to the inevitably existed radial velocity measurement errors,the mapping relationship between the radial velocity measurement error and the velocity determination error is derived.The probability distribution function of velocity determination errors is obtained when the radial velocity measurement errors subject to zero-mean Gaussian distribution,and the analytical expressions of the velocity determination errors' mean and variance under certain condition are achieved.Theoretical and simulation analyses show that the influence of the radial velocity measurement errors on the velocity determination error achieves minimum when the line-of-sights of three stars are orthogonal to each other.Simulation analyses also show how the error propagation process is influenced by the angles between stars.These research results can be used as theoretical bases for the star selection of the celestial autonomous navigation system based on velocity measurement.