Study On Monopulse Radar Forward-looking Imaging Techniques

Owing to the ability of accurate angle estimation,monopulse technique can be applied in airborne or missile-borne radar forward-looking imaging procedure.Compared to the original real beam imaging method,this so-called monopulse imaging algorithm significantly improves the azimuth resolution of forward-looking area,which is hardly achieved by synthetic aperture radar(SAR)or Doppler beam sharpening(DBS).This thesis focuses on the research of monopulse radar forward-looking imaging techniques.The monopulse imaging algorithm,the auto-focusing algorithm for monopulse imaging,and the multi-channel radar forward-looking imaging algorithm based on super resolution are investigated in detail.The main contents are summarized as follows:1.The basic principles of monopulse angle estimation are introduced in detail,and the model of echo signal for forward-looking monopulse radar is established.Based on that,the signal processing procedure of monopulse imaging algorithm is provided,with its feasibility in practical application verified by simulation and experimental results.At last,the performance of monopulse imaging algorithm is analyzed in detail.2.The problem of azimuth defocus caused by errors of monopulse response curve in practical application is investigated.To remedy this,two auto-focusing algorithms for monopulse imaging,i.e.,the auto-focusing algorithm based on minimum entropy and the strong scaterrer auto-focusing algorithm,are proposed respectively.Simulation and experimental results are employed to verify the performance of the two algorithms.3.To deal with the failure in angle estimation of monopulse technique when more than one target appears in beam simultaneously,the multi-channel radar forward-looking imaging algorithm based on super resolution,which can further improve the azimuth resolution as compared to monopulse imaging algorithm,is investigated.By introducing Capon beam forming algorithm and MUSIC algorithm into multi-channel radar forward-looking imaging procedure,two imaging algorithms are proposed,with the entire signal processing steps provided in detail.At last,the performance of the proposed algorithms is evaluated by simulation results.