Research On SAR And ISAR Imaging Technology Based On High Frequency Electromagnetic Algorithm

Radar plays an indispensable role in modern information warfare.Radar plays an important role in target recognition,ranging and imaging.With the rapid development of radar technology,the resolution of radar is increasing,the working frequency extends to the high frequency area,and the wavelength of the incident wave is gradually decreasing,which makes the target size increasing.In the research of recognition and imaging of large ships and other targets,it will take a lot of manpower and financial resources to carry out research with experimental methods.In general,electromagnetic algorithms are used to simulate these problems,and the high frequency approximation method is often used in the imaging problem of this kind of large size target.In this paper,the basic theory of physical optics(PO)is introduced in frequency domain high frequency approximation.The iterative physical optics(IPO)and the improved PO algorithm combined with the theory of TE,TM wave decomposition and synthesis are introduced for the strong coupling effect.The time domain physical and optical method(TDPO),the time domain iterative physical optics(TDIPO)and the time domain jumping ray algorithm(TDSBR)combined with the ray tracing theory are mainly introduced in the time domain high frequency approximation.The latter two algorithms consider the coupling effect between targets.In view of the wider pulse width of radar signal source,this paper proposes a method of combining the transfer function method with the time domain high frequency algorithm to simulate the target electromagnetic scattering characteristics.The electromagnetic simulation data of the target echo can be obtained by the high-frequency electromagnetic algorithm,and the electromagnetic imaging simulation of the target can be carried out by combining the collected echo data with the imaging method.At present,the two main modes are synthetic aperture radar imaging(SAR)and inverse synthetic aperture radar imaging(ISAR).This paper first introduces the basic principle of SAR imaging and the working mode of the positive side view radar,and uses the distance Doppler(R-D)algorithm to simulate the imaging of the simple target.Secondly,this paper introduces the basic principle of ISAR imaging and the working mode of turntable imaging,and uses a fast FFT imaging algorithm under small angle to simulate the imaging of simple targets without considering the distance migration.