光学像差对星点质心定位误差的影响分析

星点质心定位精度直接决定了星敏感器姿态测量精度的极限，其误差源之一是弥散斑模型的选取。星敏感器光学系统像差无法完全消除，必然影响弥散斑分布，研究光学像差对星点质心定位误差的影响对工程应用具有重要意义。文中以Gauss弥散斑模型为比较，研究了离焦等4种光学像差对星点质心定位的影响机理和分布规律，结合质心定位的物理过程推得光学像差影响下的误差解析式，并实现数值仿真，结果表明:光学像差形成不同的弥散斑模型，导致不同的星点质心定位误差分布；星点弥散斑边缘能量减弱趋势对质心定位误差影响较大，若控制光学像差使相应弥散斑边缘能量呈缓慢趋势减弱，则有利于定位误差的减小。光学像差影响下的星点质心定位误差分析对相应的误差补偿具有指导意义，提出的各光学像差的控制意见有利于指导星敏感器光学系统设计。

Analysis of effect of optical aberration on star centroid location error

Centroid location accuracy of stars directly affects the limits of star sensor attitude measurement accuracy, one centroid location error is selection of spot model of star image energy in the algorithm. Star sensor's optical system inevitably has aberration which leads to changing of spot distribution, therefore, it has a realistic significance to explore the effect of optical aberrations on centroid location error for engineering application. Compared with the Gauss function model, four kinds of optical aberration were studied such as defocus and distribution law of centroid location error under the influence of the optical aberration. The analytical expression of location error was calculated combining with the physical process of centroid location, and its numerical simulation was achieved. Experimental results show that the different aberration result in respective spot distribution, further, different centroid location error. And the centroid location error will decrease if the edge energy gets lower evenly at a slow speed according to controlling aberration well. The analysis of centroid location error will help to guide the latter systematic error compensation, and principle of controlling optical aberration will guide the optical system design of star sensor.