为分析星敏感器内部各误差因素对其测量精度的影响，建立了星敏感器的理想模型和实际模型；基于几何成像理论，分析了焦距误差、主点偏移、光学镜头畸变、焦平面倾斜以及焦平面绕视轴方向的旋转等误差因素对星光成像矢量测量精度、视场内星间角距测量精度的影响，设计了测量精度评价指标，并通过仿真实验进行了定量分析，论证了不同参数误差、不同观星方位与测量精度的关系，焦距误差、主点偏移和镜头畸变是影响测量精度的主要因素，在使用时必须加以校正。

To analyze the effect of various inner error factors of star sensor on measurement accuracy, the ideal and actual models of star sensor were set up.Based on geometric imaging principle, the impacts of such error factors as focal length uncertainty, principal point displacement, lens distortion, tilt and rotation about visual axis of focal plane etc.on measurement accuracy of starlight imaging vector and of angle separations between stars in FOV were analyzed.The evaluation indicators of measurements accuracy were proposed, and quantitative analysis was made through simulation.The relationship of parameter error and star observing direction with measurements accuracy was discussed.It is showed that the focal length uncertainty, principal point displacement and lens distortion are the main influential factors of accuracy, which should be corrected before use.