基于星点质心运动轨迹模糊星图退化参数估计

Estimation of degradation parameters of smearing star image based on motion trajectory of star′s centroid

当运动角速度超过允许的最大角速度时,星敏感器工作在动态环境下,星点的灰度特征将不再呈高斯分布,这将影响质心计算的精度。给出了在角速度的影响下星点质心运动轨迹的解析解,并结合曝光时间短的特点,对轨迹的参数方程进行简化并通过仿真分析验证了其精确性。分析了退化星点灰度分布特征,并结合星点质心运动轨迹方程提出基于质心运动轨迹对星图的退化参数进行估计的方法。通过仿真实验,完成了对退化长度及退化方向的估计,对退化长度的估计误差不超过0.8个像素,对退化方向的估计误差不超过2°,并证实了该方法能有效提高质心计算精度。

Star′s gray intensity wouldn′t follow 2-D Gaussian distribution when the rotational velocity exceeded the highest rotational velocity which would affect the processing precision of centroid of star spot. The analytical solution of motion trajectory of star′s centroid was simplified considering that the exposure time was short enough, and then the precision of the linear approximation was analyzed through simulation. The character of gray intensity of smearing star was analyzed based on the simplified trajectory, then a novel algorithm was proposed to estimate the degradation parameters of smearing star image. Through simulation and experiment, the validity of the proposed algorithm has been testified, the largest error of estimated blur length is around 0.8 of a pixel, while error of the estimated blur direction is about 2°, feasibility of the proposed method has also been validated through simulations.