高精度数字星等模拟器的设计

Design of High-Precision Digital Star Magnitude Simulator

星等模拟器是星敏感器的地面标定和关键测试设备。设计了一种准直光学系统用于模拟"无穷远"处的星光,系统采用4片式透镜分离结构,满足微弱光需求的同时,提升了系统的成像质量,光学系统出瞳外置,实现了高精度星图的模拟;基于脉冲宽度调制(PWM)信号调节LED光源作为系统的高精度可变目标光源,对比度为631…1,光源系统实现了单点可控和联合调控的功能;在暗室条件下对星等进行测试。结果表明在10μm的星点孔下,系统实现了0~7等星控制,各星等的微调范围不小于半个星等,模拟精度小于0.1(重复实验定点落在±0.4%的要求范围内),光谱范围覆盖整个可见光。

Magnitude simulator is the calibration and critical testing equipment on the ground for star sensor. A collimation optical system is designed to simulate the ＂ infinity＂ starlight. In this system, four lens separation structure is used to meet the demand of weak light and improve the quality of image. The beam passes through the external exit pupil to the star sensor, and high-precision star image simulation is achieved. Based on the pulse width modulation （PWM） signal, a single-point controllable LED light is adjusted as the high-precision variable light source. With a contrast of 631 ： 1, the single-point control and joint control functions of the light source system are realized. The magnitude is tested in a darkroom. Results show that, under 10 μm star hole, the system can simulate 0-7 star magnitude. The magnitude of the tuning range is not less than half of a star, the simulation precision is less than 0.1 （the points of repeat tests fall within ± 0.4% of the required range）, and the spectral range covers the entire visible spectrum.