Design of optical system of wide angle infrared earth sensor and study on distortion correction

In order to meet the requirements of low orbit spacecraft guidance, navigation and control (GNC) system for light small infrared earth sensor, the design on wide angle long-waveband infrared (LWIR) optical system and its distortion correction were studied. The wide angle LWIR optical system consists of 3 germanium lenses, using the form of retro-focus imaging, its full field of view could be 140°. The operating wavelength range is 14μm~16.25μm, and F number is 0.8. The optical system is characterized by small volume, simple structure and high image quality, the miniaturization and high-precision design of the infrared globe sensor optical system can be realized. Different distortion correction formulas were established for different field ranges, and the correction error is less than 1/5 pixel size. The distortion correction method can meet the requirement for attitude measurement of sensor products.