空间相机作为空间态势感知的主要器件,需实时监测其成像质量,但旋转卫星平台观测地面靶标以测量调制传递函数(MTF)会增加技术风险且无法进行多次测量,因此需要研究无需进行平台翻转以实时测量空间相机在轨MTF的方法。利用深空背景中常见的星点作为在轨MTF测量的目标,结合点源法研究其在轨MTF测量的方法,利用高斯拟合定位和多图配准重构点扩展函数,提出最终基于星点的MTF检测方法。仿真和实验结果表明:所提方法的抗噪性好,当随机噪声标准差为40时,MTF的均方误差为10 -4量级,且对小星点目标的检测效果好,当MTF的均方误差小于0.2 pixel时,能够检测的最小弥散圆半径为0.9 pixel。

Space cameras are the major devices used for space situational awareness and their imaging quality therefore needs to be monitored in real time. However, rotating satellite platforms to observe ground targets to measure the modulation transfer function (MTF) increase the technical risk and cannot perform multiple measurements. Thus, research is required for developing a method without platform flipping for real-time measurement of the MTF of the space camera on-orbit. The final point-based point MTF detection method utilizes the common star points in the deep sky background as the target of the on-orbit MTF measurement, combined with the point source method to study its on-orbit MTF measurement method, and utilizes Gaussian fitting positioning and multi-graph registration to reconstruct the point spread function. Simulation and experimental results show that the proposed method has desirable noise immunity. When the standard deviation of random noise is 40, the mean square error of the MTF is in the order of 10 ^-4, and the detection effect of small star targets is good. When the mean square error of MTF is less than 0.2 pixel, the smallest radius of the circle of confusion that can be detected is 0.9 pixel.