A sparse aperture imaging system with optimal rotating pupil

Space-based high-resolution imaging system has a trend to broadband spectrum imaging in geosynchronous orbits. The resolution of an imaging system is related to the aperture size, the height of the orbit of the system, and the detection wavelength. For traditional imaging system, it is difficult to increase the aperture size due to the limitation of manufacturing level, processing cost and load weight. The optical sparse aperture (OSA) system uses a number of independent subaperture systems with a smaller size and the same standard to collect light from objects and synthetizes a blur image in focal plane, which can achieve a large equivalent aperture size. However, with the increasing number of the sub-aperture systems, the system structure becomes more complicated, which is difficult to be used in practice. This paper presents an approach to search for an optimal OSA system based on annular pupil structure and reduce the number of sub-aperture systems by rotating the pupil to compensate PSF information and improve the image quality in OSA system. In this paper, a 12-aperture OSA system applied for earth observation in geosynchronous orbit are designed optimally to realize the resolution of 1m. The optimal scheme for rotating the pupil with twelve apertures under the threesymmetric structure was determined, and the MTF of the hexagonal structure was obtained. The simulation results show that the method can be applied to design a OSA system with a rotating pupil, synthesize all images within the rotation period, collect all frequency information, and restore high-resolution images using image restoration techniques.