Research On Ground Target Recognition Technology Of Wideband Polarization Radar

In the face of the increasingly complex battlefield environment of modern information war,it has been difficult for the traditional radar signal processing technology to accurately detect the ground target in terms of the radar airborne platform ground target recognition system,so the need for radar target recognition technology is becoming more and more urgent.With the development of radar polarization technology,the target recognition technology based on high resolution one-dimensional range profile of target polarization has gradually become a hot topic for the researchers in the field of radar target recognition.The polarized high resolution one-dimensional range profile can reflect the fine geometric structure information of the target along the radar line of sight and the polarization scattering characteristics of the target.Also,its imaging conditions are simple;it's easy to obtain;it's in low computation and storage pressure.At present,the target recognition technology based on high resolution one-dimensional range profile of target polarization has achieved some progress and breakthrough,but radar target recognition system for ground launch platform,a specific applications,there are still some problems,like Incomplete training template library caused by non cooperation of target,low separability of feature space caused by ground interference and target similarity,and low SNR and false target interference caused by complex ground battlefield environment,which seriously impact the overall performance of the ground radar target recognition system.This thesis focuses on the problems of radar ground target recognition technology in the above applications,aiming to realize the target recognition in the complex battlefield environment.Specifically,following aspects are included: 1.In order to solve the problem that non-cooperative target template library is not complete in high resolution one-dimensional range profile recognition technology of radar ground target,a high resolution one-dimensional range profile simulation method based on FEKO radar electromagnetic simulation software is studied.By importing the CAD model of the target to be simulated into the software,and using the RCS calculation method integrated with the software,the high resolution one-dimensional distance profile of the target is obtained,so as to build a complete target training template library.By comparing with the measured data of the target,the high resolution one-dimensional range profile generated by the method is highly similar to the measured data of the target.The method is used to generate the recognition training template library and test it based on the measured data,which verifies the effectiveness of the method in the target recognition technology.2.In order to extract the low-dimensional and highly separable features of high resolution one-dimensional range profile,a feature extraction method based on the polarization decomposition of target polarization was proposed.This method is based on a polarization decomposition of target range to reach multi-channel high resolution feature extraction.Compared to the traditional method of direct feature extraction for polarimetric high resolution range profile,the method can make full use of polarization information of target polarization high resolution range profile,achieving maximization between the intra class correlation and inter class difference in target feature space,at the same time,reducing the redundant information of target characteristics,and guaranteeing the low dimension of characteristics,so that the overall performance of the target recognition system is promoted.The method is verified by the measured data.The results show that,under the condition of ensuring the low dimension of target eigenvector,this method can effectively improve the separability of feature vectors among targets,and improve the overall performance of the high resolution one-dimensional range profile recognition system.3.Aiming at the ground target recognition system of the radar launching platform,a target recognition method based on wideband polarization radar target high resolution onedimensional range profile discrimination-classification secondary processing is proposed,dividing the process for the target recognition system of the ground radar into two stages: target identification and target classification.During target identification stage,the azimuth sensitivity of the high resolution range profile of the target will result in the multi region aggregation of the target's feature space.This method uses rapid density clustering algorithm to divide feature space,and then use discriminator based on the density weighted support vector domain description to complete the target identification to achieve identification of targets in the library(interested targets)and rejection of interferences outside the library(ground interferences and false targets).In the target classification stage,the support vector machine based on gaussian kernel function is used to realize the target classification and complete the type analysis of the target in the library.This method solves the problem of identification and classification between the target in the library and the interference outside the library,and improves the performance of the target recognition system.By dividing the region of the training feature space,a more accurate description of the feature space is realized on the basis of effectively reducing the computational complexity.Finally,the experimental results show that the proposed method has excellent identification and classification performance having practical potential in engineering.