紫外星敏感器光学系统设计及其鬼像分析
Optical system design and ghost analysis for ultraviolet star sensor
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摘要: 针对空间紫外波段航天器自主导航姿态敏感器的特殊需求,提出基于正组为FK5和熔石英、负组为QF1的新型紫外玻璃组合方法,设计了波段330~365 nm、焦距80 mm、F数1.6、视场角88的紫外星敏感器。基于近轴鬼像能量计算的方法对鬼像抑制指标进行计算。利用Code V对系统轴上一阶鬼像进行初步的分析与判断,再利用非序列光线追迹对系统轴外多阶鬼像进行仿真计算,得到完备的轴外鬼像能量分布。结果表明,该光学系统结构紧凑,像质良好,各视场成像弥散斑均方根半径10 m内能量集中度大于80%,相对畸变优于0.05%,在相差7等星的动态范围下,像面处亮星最大鬼像光斑照度仅为暗星照度的1/21,满足紫外星敏感器的探测需求。Abstract: To satisfy the requirements of space ultraviolet autonomous navigation sensor, a method based on usual glass combination was proposed to supersede costliness special glass such as CaF2. An ultraviolet star sensor was designed, whose waveband was 330-365 nm, F number was 1.6 and field of view was 88. The ghost suppression target was calculated by paraxial ray tracing. The paraxial first-order ghost was preliminarily analyzed and estimated by Code V, then the off axis multi-orders ghost and energy distribution was simulated by non-sequential ray tracing technology. The results show that this optical system has compact structures and high image quality. The dispersion spot radius is smaller than 10 m, and relative distortion is less than 0.05%. With a target dynamic range of 7 magnitudes, the ghost irradiance of the brightest star is 1/21 of the darkest star and meets the requirements of ultraviolet star sensor.