天基平台宽谱段成像光学系统设计北大核心CSCD

针对用于地球静止轨道卫星的遥感面阵快照式成像光谱仪传输数据量过大引起的数据传输困难、信号采集处理时间长的问题,利用地球静止轨道平台可以长期驻留固定区域上空的特点,提出采用压缩感知的大口径宽谱段快照式光谱仪方案,对其光学系统结构进行设计,并对相关参数进行了计算。物镜采用同轴三反式无焦系统,用分色片对系统分光,经过对各系统进行优化处理,最终获得了幅宽为400 km×400 km,可见光地面像元分辨率为50 m、中波红外地面像元分辨率为400 m、长波红外地面像元分辨率为625 m的光学系统。该设计中,可见光路在78.125 lp/mm的MTF高于0.455,中波红外的光谱分辨率为光路在33.3 lp/mm处的MTF高于0.518,长波红外光路在20.8 lp/mm处的MTF高于0.498;可见光光谱分辨率为20 nm、中波红外的光谱分辨率为50 nm、长波红外的光谱分辨率为150 nm;可见光路二级光谱小于0.05 mm,设计结果具有良好的成像质量,各部分光学系统成像质量接近衍射极限,设计结果满足应用和指标需求。

Optical design of visual and infrared imaging system based on space-based platform

Due to the excessive data transmission of the geostationary orbit array staring spectrometer, the data transmission is difficulty and signal acquisition and processing time is long. According to the characteristic that geostationary orbit platform can stay over the fixed area for a long time, a scheme of large aperture visual and infrared snapshot spectrometer based on compressive sensing was proposed. The physical model of compressive sensing spectral imaging was analyzed, the structure of the optical system was designed, and the relevant parameters were calculated. A coaxial three-mirror afocal optical system was used in objective lens, and dichroic films were used to split the spectrum. After optimization, the optical system was shown with a width of 400 km x 400 km, 50 m Ground Sample Distance (GSD) in visible part, 400 m GSD in Middle Wave Infrared (MWIR) part and 625 m GSD in Long Wave Infrared (LWIR) part. The results show that the MTF in the visible part is higher than 0.455 at 78.125 lp/mm, the MTF in mid-wave infrared region is higher than 0.518 at 33.3 lp/mm, and the MTF is higher than 0.498 at 20.8 lp/mm in long-wave infrared region. The spectral resolutions are 20 nm, 50 nm, and 150 nm in the visible part, the mid-wave infrared region, and the long-wave infrared region, respectively. The second-order spectrum of the visual part is less than 0.05 mm. The optical system has good imaging performance, and the imaging quality of each part of the optical system is close to the diffraction limit, which meets the needs of applications and indicators.