空间推扫相机的光学系统要求具有大视场、大口径、低F数等特点，据此设计了一种3波段光学系统。在参考国内外各种扫描或推扫相机结构的基础上，根据像差理论和系统要求，采用有效的分光方式和紧凑的光路结构，对不同的波段采用不同的像差校正方法，以及对系统优化组合后，最终得到了一个实用的光学系统。该系统包括可见、中波红外和长波红外波段，视场达到2.93°×0.3°，可见波段的F数为3.8，中波和长波波段的F数为1.9。从设计结果可以看出，系统3个波段的光学调制传递函数（MTF）都接近衍射极限。

A multi-band optical system was designed for the push-broom space camera covering visible，medium infrared and far infrared wavebands. The system has large aperture and low F number due to the requirement of large FOV. With the reference to various scanning and push-broom cameras at home and abroad, an optimized compact optical system was achieved by an effective beam-splitting approach, in which the aberrations of three channels were corrected respectively according to the aberration theory and system requirement. The field-of-view of the optical system is 2.93°×0.3°, and F number for the visible light is 3.8 while F number for both of medium infrared and far infrared is 1.9. The design result indicates that the optical modulation transfer functions of the three bands within the cut-off frequency are all close to the diffraction limitation.