大F数长焦距空间相机光学系统设计

Optical System Design of Space Camera with Large F number and Long Focal Length

随着空间技术的不断发展,地元分辨率不断提高,空间相机光学系统的设计不断提出新的要求。分析了长焦距空间相机光学系统设计过程中需要考虑的问题,研究了大F数、长焦距空间光学系统的设计原理,并进行了光学系统设计。设计了谱段位于500~800 nm,焦距f=7200 mm,F=14.4的大F数、长焦距的折轴三反光学系统。结果表明,光学系统视场角达到1.6°,在450 km的轨道上,地面幅宽可以达到12.5 km,像元尺寸为10μm时,地面像元分辨率达到0.62 m,当中心遮拦为6%时,Nyquist频率（50 lp/mm）处调制传递函数（MTF）优于0.38,成像质量达到衍射极限,光学系统畸变量优于0.5%,可以满足高分辨率空间相机对地观测的使用要求,同时也验证了大F数、长焦距光学系统的设计原理。

With the development of space technology,the optical system design must be satisfied with the lastest demand due to the ground sample distance（GSD） steadily improving.The issues of the optical system design is discussed,the space optical system design principle with large F number,long focal length is analyzed and a reflective optical system which is characterized by the spectrum band 500~800 nm,focal length of 7200 mm and F number of 14.4 is designed.The result indicates that the field angle reaches 1.6°,the ground width reaches 12.5 km and the graund sample distance（GSD） reaches 0.62 m at 450 km orbit,the quality of image approaches the diffraction limited,modulation transfer function（MTF） reaches 0.38 at the Nyquist frequency of 50 lp/mm with 6% central obscure,and optical system distortion is less than 0.5%.So this kind of optical system can meet the demand for the use of high resolution space cameras.At the same time,the large F number,long focal length design principle are approved.