An Efficient ISAR Image Simulation Method for 3-D Electric-Large PEC Rough Surface

Abstract

This article presents a fast inverse synthetic aperture radar (ISAR) image simulation algorithm for electric-large rough surfaces based on the 3-D beam simulation method (BSM) and point spreading function (PSF). It first computes the induced current with BSM and then convolutes it with PSF to generate the ISAR image. The BSM decomposes the large incident beam into overlapped and truncated sub-beams. Each sub-beam illuminates a small region of the rough surface, and the impedance matrix is remarkably reduced small enough for fast full-wave electromagnetic (EM) scattering computation. The edge energy suppression of the sub-beam enables each sub-block to be calculated independently and parallelly. The PSF convolution kernel is derived to generate the ISAR image fast with the induced current at a central frequency and central incident angle. The numerical simulation demonstrates that the proposed BSM-PSF image simulation method remarkably reduces the unknowns of each method of moment (MoM) equation and avoids redundant matrix solutions for sweep frequencies and angles while keeping the correlation with the traditional fast Fourier transform (FFT) method over 0.9. Moreover, for high-resolution imaging, the interpolated PSF is derived.