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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。
The positioning accuracy of star centroid directly determines the limit of star sensor attitude measurement accuracy. One of the error sources is the selection of diffusion speckle model. The aberration of star sensor optical system can not be completely eliminated, which will inevitably affect the distribution of dispersive spots. It is of great significance to study the influence of optical aberration on the positioning error of the centroid of the star sensor. In this paper, compared with the Gauss speckle model, the mechanism and distribution of the four optical aberrations, such as defocus, on the localization of the centroids are studied. The error analysis equation under the influence of optical aberration is derived by physical process of centroid localization. The numerical simulation results show that the optical aberration forms different speckle model, which results in the different localization error of the centroid of the star point. The tendency of the edge weakening of the speckle speckle has a greater impact on the centroid localization error. If the control optical aberration makes the corresponding dispersion The edge of the spot has a slow trend of weakening, which is conducive to the reduction of positioning error. The error analysis of the centroid localization under the influence of optical aberration is of guiding significance to the corresponding error compensation. The proposed control opinion of each optical aberration is helpful to guide the design of the star sensor optical system.