Research On Wide-angle ISAR Imaging Method Based On Fluctuating Scattering Model

Inverse Synthetic Aperture Radar(ISAR)imaging technology uses the relative motion between the target and the radar,and ISAR has the ability to perform high-resolution imaging of non-cooperative targets independent of the day and the weather.It is widely used in civil and military fields.Today,with the development of radar systems and imaging technologies,it is necessary to increase the imaging rotation angle in order to obtain high resolution in the azimuth direction.This has brought new problems for ISAR imaging and put forward new challenges for ISAR imaging methods.This article mainly aims at the problem of Migration Through Range Cells(MTRC)in ISAR imaging and the anisotropy of the scattering center of fluctuating targets under the conditions of high-resolution and wide-angle imaging.Under the conditions of wide-angle imaging,the target scattering fluctuates in frequency and azimuth dimensions,which makes the traditional scattering model unable to match.This thesis studies the fluctuating scattering model for this problem,and further realizes the imaging method of wide-angle ISAR based on the fluctuating scattering model.The main work completed in this thesis is as follows:(1)Aiming at the problem of Migration Through Range Cells in high-resolution and wide-angle ISAR imaging,researched and realized the migration through range cells correction method based on Keystone transform,and further analyzed the error characteristics and applicable conditions of the method;(2)Aiming at the problem of the anisotropy of the scattering center of the wide-angle ISAR target,the fluctuating scattering model is studied by using the fluctuating target modeling method,and its effectiveness in the characterization of the fluctuating scattering characteristics of the wide-angle target is verified,and the accuracy of the model was analyzed through simulation;(3)Aiming at the problem of defocusing of the imaging results of wide-angle ISAR due to the mismatch of the scattering model,based on the fluctuating scattering model,the method of extracting the scattering center parameters based on the improved Orthogonal Matching Pursuit is studied,and its error characteristics are simulated and analyzed.A wide-angle ISAR imaging method based on the fluctuating scattering model is realized.