Research On Modeling Of Radar Irregular Feature Parameters

Electronic reconnaissance is an extremely important part of electronic countermeasures.Its main role is to detect enemy radar signals and obtain information.Nowadays,in order to improve its anti-interception capability and anti-jamming capability,radar signals use a large number of pseudo-random codes,resulting in increasingly complex signal forms,so that electronic reconnaissance signal processing becomes more and more difficult.The process of electronic reconnaissance signal in this thesis mainly includes coding mode identification,parameter estimation,code sequence identification and prediction.The study of radar non-regular feature parameters mainly refers to the research of pseudo-random sequences used for parameter transformation in radar signals.One of the important contents in electronic reconnaissance radar signal processing is analyzing the structural features of these pseudo-random sequences and making predictions.Only by mastering the characteristics of the coding sequence can we take the initiative in the subsequent electronic countermeasures.Nowadays,many researches are focused on the identification and parameter estimation of radar signals in complex systems,however,few are studied on the identification and prediction of radar code sequences.Therefore,it is necessary to conduct in-depth analysis.This thesis first analyzes the typical pulse radar signal,and briefly describes the encoding method identification method and parameter estimation algorithm.Then,the characteristics of the coding sequence,the recognition and prediction methods are mainly studied.Two code sequence identification algorithms are proposed for the characteristics of radar systems.Finally,an overall design scheme of pulse radar signal processing in electronic reconnaissance systems is proposed and software is completed.The main contents are as follows:(1)A typical pulse radar signal model has been established,and characteristic analysis has been performed for typical coding methods such as two-phase coding,four-phase coding,intra-pulse frequency coding,inter-pulse frequency coding,and pulse repetition interval(PRI)coding.Then according to the characteristics of the coding method,a reasonable and easy-to-calculate coding method is proposed.(2)Firstly,the common parameter estimation methods in electronic reconnaissance systems for phase encoding,frequency encoding,and PRI encoded signals are analyzed,including carrier frequency estimation,code rate estimation,and estimation of arrival time.Then it describes in detail the nature of the sequence,the generation method,the predictability and the common reconstruction prediction methods.The sequence includes m-sequence,Bark code sequence,Bark code mixed coding sequence,Lempel-Greenberger(L-G)model code sequence and chaotic sequence.Finally,based on the characteristics of the radar system,a short-signal m-sequence identification algorithm and a short-signal L-G model identification algorithm are proposed,which solves the problem of the limited length of the received signal in the radar system.(3)The design of signal generation software and modeling prediction software are proposed.Complete the Matrix Laboratory Graphical User Interface(Matlab GUI)software.The existing code sequence identification and prediction method is improved so that it can adapt to a certain error rate condition.Change the parameters to conduct a large number of experiments to verify the feasibility of the software and obtain the software applicable boundary conditions.