调制传递函数(MTF)可用来评估高分辨率光学卫星传感器像质，在轨MTF检测对于高分辨率卫星遥感数据的应用和未来卫星遥感器的发展具有重要意义。提出一种基于反射点源的直接检测方法，利用遥感影像数据计算得到成像系统的点扩展函数(PSF)，进而获取系统的MTF值。根据成像关系和点光源图像数据，并利用非线性方程优化求解的方式得到被测光学卫星传感器成像系统的一维线扩展函数值，进而验证了可近似用高斯模型来表征高分辨率光学卫星传感器的PSF。实验结果表明，基于反射点源的光学卫星传感器在轨MTF检测结果与基于刃边靶标的在轨MTF检测结果的差异小于5%，能够实现高分辨率光学卫星传感器的在轨MTF检测。

Modulation transfer function (MTF) can be used to evaluate the image quality of high resolution optical satellite sensors. On-orbit MTF detection is significant to the application of high resolution satellite remote sensing data and the development of future satellite sensors. A directly detection method based on reflected point source is presented, and the point spread function (PSF) and MTF value are obtained based on remote sensing image data. According to the imaging relationship and point source imaging data, the one-dimensional line spread function value of optical satellite sensor imaging system can be acquired by way of solving non-linear equations. Additionally, the Gaussian model which is usually used to characterize the PSF of high resolution optical satellite sensor is also verified. The results show that the difference of on-orbit MTF detection results of optical satellite sensor based on reflected point sources is less than 5% compared with that of the method based on knife-edge tarps. The proposed approach can achieve on-orbit MTF detection for high resolution optical satellite sensor.