星模拟器作为星敏感器的地面标定系统, 用来模拟星点像的大小、星等、光谱、色温、星的位置及星之间的角距等。随着航天技术的不断发展, 对星模拟器本身的要求也越来越高, 进而使星模拟器重要部件准直光学系统的设计成为关键因素。利用离轴反射式光学系统无色差、体积小、光利用率高、中心无遮拦等特点, 提出一种离轴抛物面式准直光学系统。该系统由离轴主抛物面反射镜和次平面反射镜组成, 实现了通光口径为Φ300 mm, 焦距为3 000 mm, 视场角为30′的准直光学系统设计, 经像质分析表明, 在视场角内畸变为0.006 2%(小于0.01%), MTF达到衍射极限, 波相差为0.071 6 λ, 所设计的光学系统能满足要求, 并论述了准直光学系统的装校过程。

Star simulator, as the ground calibration system of star sensor, can be used to simulate the star involving its size, magnitude, spectrum, color temperature, position and the angular distance between stars, etc.With the continuous development of space technology, the requirement of the star simulator itself has become higher, and then the design of collimation optical system for star simulator important component has become the key factor. Based on the characteristics of off-axis reflective optical system which has no chromatic aberration, small volume, high light efficiency and the center without blocking, an off-axis parabolic collimation optical system was proposed, and the assembly and calibration process was discussed. The system consists of an off-axis parabolic mirror and a plane mirror, which has a clear aperture of Φ300 mm, focal length of 3 000 mm, and viewing angle of 30′.The image quality analysis shows when the distortion in field of view is 0.006 2%(<0.01%), the modulation transfer function (MTF)reaches the diffraction limit and the wave aberration is 0.071 6 λ.This design of the optical system can meet the requirements.