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×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.