低成本、高性能对地遥感微纳卫星是当前研究和开发的热点, 为适应微纳卫星平台, 要求空间相机具备小型、轻量化的特点。在其体积和质量的限制下, 设计结构尽可能紧凑的长焦距大视场望远物镜是成功研制高分辨率对地遥感光学相机的关键, 研究利用同轴四反射镜系统解决这一问题的可能性。首先, 介绍无二次遮拦同轴四反射镜望远物镜的组成与工作原理; 基于近轴光学和初级像差理论, 导出几何约束条件和初级像差公式, 给出结构紧凑的长焦距同轴四反镜系统的设计思想与方法; 最后给出举例及设计结果。优化设计了全视场角1°×1°、有效焦距2 100 mm、F数为7的同轴四反射光学系统, 总长228 mm, 约为有效焦距的1/9,结构简单紧凑, 像质接近衍射极限。

The earth-observing remote sensing micro/nano satellite with low-cost and high-performance is the focus of the current research and development. In order to adapt to the micro/nano satellite′s platform, the camera is often required to be compact and light weight. Limited of its volume and weight, designing a long focal length, wide-field telescope as compact as possible is the key of successfully manufacturing the high-resolution remote sensing optical camera. The possibility of solving this problem by using on-axis four-mirror system is studied. First of all, the basic composition and the working principle of on-axis four-mirror system without secondary obscuration was introduced. Then, the conditions of geometric constraint and the formulas of primary aberrations were presented based on Gauss and optical aberration theory. The design idea and method of the compact on-axis four-mirror system with long focal length were presented. Finally, an optimized optical system was given, with full field angle is 1°×1°, effective focal length (EFL) is 2 100 mm, F number is 7, respectively. The total length of this system is 228 mm, only about 1/9 of EFL. This optical system is simple and compact and its imaging quality is near diffraction limit.