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Study On Synthetical Reconaissance And Analysis Techniques Of Radar Network Information

Posted on:2018-07-30Degree:DoctorType:Dissertation
Country:ChinaCandidate:S S LuFull Text:PDF
GTID:1368330623450464Subject:Information and Communication Engineering
Abstract/Summary:PDF Full Text Request
Netted radar system,which achieves interconnected and comprehensive treatment of radar information within the net by means of communication,poses great challenges to electronic warfare.Radar electronic reconnaissance is an important means to obtain the military intelligence information and electromagnetic states of the battlefield,occupying an important position in the electronic countermeasure.Traditional radar electronic reconnaissance technologies commonly analyze the radar signal and communication signal within netted radar system in a separated way,the radar signal and communication signal are seldom considered together in a combined way.Therefore,traditional radar electronic reconnaissance technologies can hardly achieve a thorough description of netted radar system.With considerations above,this paper studies the electronic reconnaissance of netted radar system at the background of array reconnaissance receiver,and synthesizes the analyses of the radar signals and communication signals within the netted radar system,with purpose of achieving the recognition of the pattern of netted radar system.The key techniques studied mainly include four aspects as follows,namely,the blind source separation of composite signal in netted radar system,modulation feature identification of communication signal in netted radar system,radar scanning rule analysis,and radar networking mode recognition based on combined information from radar and communication signal.In the environment of netted radar system where the aliasing of radar signals and communication signals is serious,the separation of composite signal is a foundation of subsequent signal processing and feature analysis.Compared with the spatial filtering method based on beam forming technology,blind source separation method is not sensitive to sensor array error,and needs less prior knowledge,so it has a good ability to be adapted in the battlefield.The existing blind source separation methods commonly assume that no noise is present,which limits the application of separation algorithm in a real environment.This paper,with the signal blind source separation in a noise situation being the main line of research,analyzes the stable point problem of blind source separation algorithm based on kurtosis maximization criterion in a noise situation.Based on the analyses of stable point,this paper proposes a robust blind source separation algorithm.Simulation experiments prove that the separation performance of the proposed method,which approaches the upper limit given by the minimum mean square error separation matrix,is improved in terms of the criterion of signal to interference and noise ratio.The features of communication signal in netted radar system,such as signal modulation mode and traffic flow,are important evidences to recognize the pattern of radar networking mode.Meanwhile,the recognization of modulation mode serves as an important foundation of the analysis of the communication information within the netted radar system.Considering the problem that the modulation mode recognition algorithm based on spectral detection would deteriorate when mulitiple spectrum peaks are present,the paper proposes a robust modulation mode recognition algorithm based on spectral detection.By additionally optimizing recognization process,the method achieves more accuracy for modulation mode recognition.Considering the problem that the estimate error of carrier frequency would result in the rotation of constellation diagram and hinder the modulation recognition,the paper introduces a novel carrier frequency offset estimation algorithm based on the M power of code sequence.The proposed method can improve the estimate accuracy of carrier frequency,and protect constellation diagram from being rotated.Combing the mean likelihood ratio detection method,the paper improves the accuracy of the modulation recognition.Radar beam scanning mode,which reflects the work mode of radars in netted radar system,is another important evidence to recognize the pattern of radar networking mode.The paper studies the method for analyzing antenna scan type,for both electronic scanning radar and mechanical scanning radar.For electronic scanning radar,the paper analyzes the amplitude characteristics of received signal,and uses the amplitude characteristics of signal in different search cycles for the rebuilt of the scanning search rule.For the mechanical scanning radar,as several scan periods are commonly needed to obtain the scan rules of radar antenna,existing methods may not be competent in rapidly dynamic environment.The paper proposes an exact directional diagram match method based on particle filter.The proposed models the problem of estimating the pointing direction of radar antenna as a nonlinear state estimation problem,and the particle filter is used to solve the model.Simulation results show that the proposed method can adapt to the change of antenna scanning speed,and can make real-time estimation of the orientation of the antenna beam.Networking mode is an important property of netted radar system.Hence,it is difficult to achieve ideal jamming effect in the following electronic countermeasures unless the networking mode of radar system can be identified correctly,and the relationships between radars within the system can be clarified.The paper ultilizes the compositive information of radar signal and communication signal within netted radar system,combines the evidence theory in the field of uncertainty reasoning,and proposes a novel radar network mode recognition method.In addition,based on the variation characteristics under the condition of electronic jamming,this paper proposes a group decision making method based on the evidence theory and intuitionistic fuzzy sets.The proposed adapts feature weights and expert weights to modify and synthesize evidences,and obtains final reliability assignment value for networking mode recognition.The correctness of the proposed method is verified simulation results.As a summary,the paper addresses the electronic reconnaissance of netted radar system,which is a significant but yet difficult problem.The paper ultilizes the compositive information of radar signal and communication signal within netted radar system,and studies the compositive reconnaissance of netted radar system.The key techniques studied mainly include,the separation of radar signals and communication signals within netted radar system,modulation recognition of communication signals,the analysis of the characteristics of radar antenna behavior,and radar networking mode recognition.The paper achieves a preliminarily comprehensive description of radar networking situation.The study on the the electronic reconnaissance of netted radar system has not only great theorectical significance but also important practical application value.
Keywords/Search Tags:Electronic Reconnaissance, Netted Radar, Blind Source Separation, Modulation Recognition, Constellation Diagram, Maximum Likelihood Estimation, Antenna Scan Type, Netting Type Recognition, Evidence Theory
PDF Full Text Request
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