Research On Anti-decoy Method Of Passive Radar Seeker

Anti-radiation missiles can cause fatal damage to enemy radar combat systems.However,with the continuous development of active decoy jamming technology,the performance of passive radar seekers has been severely reduced,weakening the combat effectiveness of anti-radiation missiles.The anti-decoy method is no longer sufficient to meet the technical requirements of seeker in modern war.Therefore,it is very necessary to carry out research on passive radar seeker anti-decoy technology.Based on the existing theory,this thesis studies several key problems encountered by passive radar seeker anti-decoy technology in actual systems.The specific content involves radar and decoy signal direction of arrival estimation,signal frequency estimation and radar recognition,etc.The main work includes:The system composition and working principle of the passive radar seeker are introduced.On this basis,the characteristics of the decoy signal and the radar signal are explained,and the principle of the active bait to decoy the passive radar seeker is deeply studied.The MUSIC direction finding method based on uniform circular array is studied,and the influence of coherent signals on the algorithm is explained.Then the influence of Doppler frequency shift on the correlation coefficient of the original coherent signals is analyzed when the anti-radiation missile is moving at high speed.It is concluded that When the array moving speed and the number of snapshots meet certain conditions,there is no need to decoherence,The conventional MUSIC algorithm can still obtain a good angle estimation performance.The simulation verifies the correctness of the conclusion.The frequency estimation method based on low-rate sampling is studied.In the actual direction finding,the carrier frequency of the radiation source cannot be obtained in advance,but the carrier frequency of the radar signal is high,and the amount of data is larger and the accuracy is lower when the traditional frequency measurement method is used.from practical demands,this article uses two sampling channels,uses a modified Rife algorithm to estimate the frequency of the two sampling signals,and finally uses the Chinese remainder theorem to solve the the fuzziness.This method requires less calculation and the accuracy of frequency estimation is close to CRLB.A method for estimating the number of sources using the Doppler shift is proposed.In view of the poor performance of traditional source number estimation methods in practical applications,This thesis is based on the principle that the frequency shift occurs when the emitter signal reach the passive radar seeker.Sampling the received signal at a low rate and estimation the number of peaks of its spectrum to obtain the number of sources,and the feasibility of the method is verified by simulation.At the same time,the impact of sampling time and array acceleration on the estimation performance is analyzed.A decoy culling method for scintillation decoying is proposed.Through coordinate change,analysis shows that when the anti-radiation missile approaches the target,the direction of arrival of the signal measured by the seeker changes continuously.When the scintillant decoy is used,the decoy works intermittently,and the angle value measured by the seeker at multiple moments,If the estimated angle of a certain radiation source does not change continuously,the radiation source is considered to be a decoy.The simulation verifies the effectiveness of the method.