大角速度条件下星像运动轨迹建模及误差评估

在大角速度条件下星敏感器成像平面上的星像会产生严重拖尾，影响星敏感器性能。为了全面认识星敏感器的星像运动轨迹形式，并定量评估星像运动对星点提取过程的影响，首先研究建立了星敏感器成像平面上星像运动轨迹的数学模型，推导出在成像平面上星像运动轨迹为一段圆弧；然后建立了星像运动时的能量分布模型，并对大角速度条件下基于质心法的星点坐标误差进行了评估，分析得到星点坐标误差的模近似可用星像运动轨迹长度的二分之一来衡量。仿真实验结果验证了所得结论的正确性。 

Star spot motion trajectory modeling and error evaluation under large angular velocity

Star spots obtained by the star sensor on the imaging plane will be seriously blurred under large angular velocity, which affects the performance of the star sensor. In order to fully understand the star spot motion blur trajectory and quantitatively evaluate the influence of the star spot motion blur on the star centroid extraction process, this paper firstly establishes the mathematical model of the star spot motion trajectory on the imaging plane. It is derived that the star spot motion blur trajectory on the imaging plane is a part of the circle during the exposure time. Then the energy distribution model of the blurred star spot is established and the star spot centroid coordinate error based on the centroid method is evaluated under the large angular velocity. It is analyzed that the modulus of the star spot centroid error can be approximated to one half of the length of the star spot motion blur trajectory. The simulation results verify the correctness of the conclusions obtained in this paper.