城市夜光遥感成像系统设计与杂散光分析

根据城市夜光遥感相机研制要求,采用COOK TMA离轴三反光学结构形式,设计了一个视场为5°×2°,焦距为500mm,F数为3.8,工作波段为0.4~0.8μm的全反射式夜光遥感相机光学系统,采用主镜、次镜、三镜共光轴设计,提高了光学装调的可行性。选择合适的初始结构参数,利用CODE V软件进行光线追迹和优化设计,结果表明:光斑的方均根直径为2.305μm,小于1/8像元,在25lp/mm奈奎斯特频率处的光学调制传递函数大于0.92,接近衍射极限。采用外遮光罩、挡光环、光阑及消光漆等消杂光设计来降低杂散光水平,利用Tracepro软件对光机系统进行杂散光的仿真分析,结果表明:轴外视场为1°~80°时,点源透过率在10-11~10-3量级;太阳抑制角为65.96°~80°时,点源透过率小于1×10^-9,满足应用要求。

Optical Design and Stray-Light Analysis of Urban Night-Light Remote Sensing Imaging System

In this study,an optical system of total-reflection night-light remote sensing is designed using the off-axis three-mirror optical structure of COOK TMA based on the development requirements of the urban night-light remote sensing cameras.Its field of view is 5°×2°,focal length is 500 mm,F number is 3.8,and working waveband is 0.4-0.8μm.The optical axes of the primary,second,and third mirrors are designed to be coaxial to improve the feasibility of optical installation and adjustment.Initially,the appropriate initial structural parameters are selected.Then,ray tracing and optimization are performed using the CODE V software.Results show that the root-mean-square diameter of the spot is 2.305μm,which is less than one eighth of a pixel.Further,the optical modulation transfer function is greater than 0.92 at Nyquist frenquency of 25 lp/mm,which is close to the diffraction limit.The external baffle,blocking rings,diaphragm,and matte paint are used to decrease the straylight level.Subsequently,the stray light of the optical-mechanical system is simulated and analyzed using the Tracepro software.The results denote that the point source transmittance is between 10-11 and 10-3 when the offaxis field of view is 1°-80°.Furthermore,the point source transmittance is less than 1×10^-9 when the solar suppression angle is 65.96°-80°,which satisfies the application requirements.