Optical System Design And Stray Light Analysis Of A Space-based Visible Camera

The optical system design and stray light analysis of a space-based visiblecamera were studied generally.First, the parameters of the optical system were determined after analyzing thecamera’s requirements, and then a Cook lens was selected as the initial structure ofthe optical system. A lens that can meet the requirements was designed afteroptimizing the initial structure by the aid of the ZEMAX software.Second, the stray light of the optical system was detailed analyzed. There are twoparts in this section. The first part introduced the basic theory of the stay light analysis,consisting of the method and the meaning. In the second part, a rectangle baffle wasdesigned by using the2D mapping software CXCA after calculated the irradiation ofthe stray light sources. The PST of the optical system was calculated by using theTRACEPRO software. The stray light increased suddenly in the off-axis angle of15degree. The paths were found after tracing rays in the analysis mode of theTRACEPRO system. The method of increasing the length of the baffle was used tosuppress the stray light paths. Compared the new baffle with the conventional one, thePST of the longer baffle can satisfy the requirements.Finally, the detector capabilities of the camera were analyzed. The stray lightphoton flux was calculated when the signal to noise ratio is5and the magnitude is6.Combined with the PST of the system, the6magnitude can be detected when thestray light’s off-axis is larger than the17degree. The farthest detector distance of asphere target that diameter is1m was calculated under the influence of stray light.Finally, the simple relationship of the system’s horizon angle and the length of bafflewas calculated according to the PST of baffle.