基于激光雷达高程数据与平面影像数据融合的三维成像技术是三维遥感探测技术的重要发展方向之一。本文设计了基于此体制的共孔径三维成像载荷的光学系统。从受限的空间尺寸出发, 以此作为设计输入条件, 得到光学系统的初始设计参数, 设计了焦距为2 400 mm, F数为5.33的偏视场同轴三反系统。采用三镜前置的方式, 大大缩短了光学系统的轴向长度, 使光学系统的轴向长度仅为焦距的1/4.36, 在有限的空间内, 实现了长焦距、高分辨率的光学系统排布。采用偏视场设计, 避免了系统内的二次遮挡。整个系统的成像质量良好, 无色差, 畸变小, 光学调制传递函数接近衍射极限, 同时其相对孔径较大, 有效通光孔径较大, 能量集中度高, 在保证高地面分辨率的同时, 满足了激光接收端对能量的需求。

3-D remote sensing based on the combination of ladar and 2-D remote sensing data is one of the most important emerging trends in the field of remote sensing. We design a co-aperture optical system to be used for 3-D remote sensing payload. In order to use the spatial limitation of the satellite as input conditions, we modify the initial equation of the three-mirror system. The original parameters are determined from the solution of the modified equation and then a coaxial three-mirror system is designed. The fields are biased to avoid secondary obstruction caused by the image plane. The focal length and F number of the system are 2 400 mm and 5.33, respectively. The tertiary mirror is placed in front of the primary mirror to shorten the on-axial length by using three plane mirrors, which resolves the contradiction between long focal length and spatial size. The system is free of chromatic aberration, has small distortion and offers a good performance. The modulation transfer function approaches the diffraction limit, and the system has a large relative aperture, of which the geometric encircled energy is confined within a circle of diameter 35 μm. The designed optical system provides good performance with high resolution and satisfies the requirements for ladar.