Design of Dexterous Four-Mirror Star Sensor with Large Aperture

star sensors lens is an important part of the star sensor attitude orbit control system, with relative aperture large, working spectrum wide, absolute distortion low characteristics, according to these characteristics, on the basis of the initial structure of the 4-mirror, the relationship between lens detection ability and relative aperture is analyzed, the lens design index is clarified, and the strong aberration correction ability of the aspherical mirror is used to optimize the design to obtain a fully reflective 4 anti-star sensor lens. Set the lens focal length 170mm, the axial length 50mm, the lens F number 2, the equivalent pupil diameter 51.2mm, and the circular field of view ±2.25°. The working band of the lens can be determined by the membrane system, without chromatic aberration.The transfer function at the spatial frequency of 35lp/mm is better than 0.6. The distortion is better than 0.01%. The diffuse spot diameter is better than 13μm. The energy concentration within the system 15μm range is better than 80%, and the vignetting coefficient is less than 0.95. The lens can be used for the subpixel accuracy spacecraft attitude orbit control system, providing a reference for the design of the space sensor navigation optical system.

On the basis of the two mirror system, two aspherical mirrors were introduced, and a new total reflection star sensitive optical system was obtained through local and global optimization using an evaluation function mainly based on the circularity of the diffuse spot. The system adopts a total reflection form, without color difference, and can achieve full spectrum and non differential imaging. The system has a focal length of 170mm, a cylinder length of 50mm, and a focal length cylinder length ratio of 1:2.1. The layout is compact, the tolerance distribution is reasonable, and it has good stray light suppression performance, meeting the needs of engineering batch quantization of star sensor systems.