Research On Airborne Co-aperture Imaging System With Infrared And Synthetic Aperture Radar

Due to the increasingly diverse imaging needs and complex imaging environment,a platform often needs to carry several imaging systems,which increases the load of the platform and increases the difficulty of motion control and information fusion.Therefore,the multi-mode composite imaging system formed by integrating imaging systems in structure and function is the development trend of all kinds of imaging platforms,including airborne reconnaissance and detection imaging platforms.In addition,multi-mode composite imaging system design technology has also become one of the research hotspots in the field of optical design at home and abroad in recent years.In this paper,an airborne co-aperture imaging system with infrared and synthetic aperture radar is designed to meet the application needs and development trend of airborne reconnaissance and detection imaging system.By sharing part of the structure,the imaging system is more compact in space,which reduces the volume and weight.And it combines the advantages of infrared system and synthetic aperture radar as well as compensates each other's defects.Moreover,it improves the environmental adaptability and functional applicability of the airborne detection imaging platform,which has a high value in research,development and application.The main research content of this paper is the design of the infrared part of airborne co-aperture imaging system with infrared and synthetic aperture radar.In addition,there are other research contents of this paper including:(1)the structural design of the coaperture imaging system;(2)design of synthetic aperture radar antenna;(3)cold aperture matching,cold reflection analysis,imaging quality evaluation and tolerance analysis with infrared optical system;(4)design of Cassegrain optical system;(5)the PW method used to calculate the initial structure of refraction system;(6)design and analysis of frequency selective surface.Firstly,according to the requirements of composite imaging system and the existing structures at home and abroad,a design scheme of co-aperture imaging system is proposed.Secondly,the antenna is designed according to the imaging principle of synthetic aperture radar and the design theory of reflector antenna.Thirdly,the antenna with known parameters is used as the first reflective surface of infrared imaging system.Combining the cold aperture matching technology,aspheric structure design and PW method,the design method of infrared imaging part of the co-aperture imaging system is created,based on that,a initial structure is calculated.Then,after optimizing initial structure,performance analysis are performed in optical software,including image quality evaluation,optical aberration analysis,cold reflection analysis,tolerance analysis,etc.Finally,the antenna performance of the synthetic aperture radar is simulated and analyzed,and the assembled infrared imaging system is tested,which verify the feasibility of the design scheme of co-aperture imaging system with infrared and synthetic aperture radar.In this paper,for the first time,synthetic aperture radar and infrared imaging system are combined.Based on the principle,a feasible design theory of co-aperture imaging system structure is proposed and verified.For the calculation of the initial structure,a program was written to reduce the calculation workload.A frequency selective surface is introduced for the design of beam splitter.It enriches the theory of microwave and infrared common aperture imaging system design,and provides new ideas for solving some difficulties in this field.