Optical System Design Method of Near-Earth Short-Wave Infrared Star Sensor

Abstract

In order to meet the urgent needs of short-wave infrared (SWIR) star sensors in near-ground navigation applications, starting from the detection capability and detection accuracy, a design method for the optical system of near-earth space star sensor is proposed, including the selection method of optical parameters and the determination method of structure parameters. Based on the presented method, the index requirements are given, and an <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">${H}$ </tex-math></inline-formula> -band catadioptric star sensor optical system with a focal length of 1174 mm, an aperture of 200 mm, and an entire field of view (FOV) of 0.8° is designed. The relative distortion is lower than 0.02%, the chromatic aberration is less than 0.1 pixels, over 90% of the star point energy is distributed in <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$3\times $ </tex-math></inline-formula> 3 pixels, the ambient temperature adaptability is acceptable, the expected consequence is achieved, and the feasibility of the method is proven. Furthermore, the stray light elimination system is designed to avoid the influence of direct sunlight on stellar imaging, and an integrated navigation system (INS) is designed to reduce the interference of solid sky background on stellar detection. The derived information of sky background radiation, degree of polarization, and angle of polarization is used to improve navigation reliability. This article can provide a theoretical foundation and technical support for the engineering application of star sensors in tanks, ships, aircraft, and missiles.