Research On Anti-active Jamming Technology Of Missile-borne Array Radar

With the development of electronic countermeasure technology,array radar is used in missile-borne radar seeker because of its flexible beam control and other characteristics,and missile-borne array radar seeker against active barrage jamming is one of the current hot research topics of precision guidance radar seeker.When the active barrage jamming is located in the sidelobe,the subarray adaptive beamforming can suppress the jamming well,but the direction pattern of the sum and difference beam will be distorted,which is not conducive to the estimation of the target angle.However,when the interference is located in the mainlobe,subarray adaptive beamforming is no longer applicable,and other anti-main lobe interference algorithms need to be researched.Therefore,the anti-active barrage jamming technology of missile-borne array radar seeker is studied in this paper.Firstly,the basic model of array radar is introduced,then adaptive beamforming,which is often used to suppress sidelobe jamming in space domain,is introduced according to the characteristics of sidelobe active barrage jamming,and sub-array adaptive beamforming is introduced according to the characteristics of projectile-borne array radar.However,this technology will lead to the distortion of the direction pattern of the sum difference beam when suppressing the sidelobe jamming,which is not conducive to the estimation of the target angle.Therefore,the sub-array constrained adaptive beamforming technology is considered.This technique can keep the monopulse ratio to the difference beam unchanged in the main lobe range,and has a better angle measurement accuracy.The effectiveness of this technique is verified by simulation in this paper.Secondly,in view of the problem that adaptive beamforming technology is no longer applicable in the case of mainlobe jamming,two methods of suppressing the mainlobe jamming based on blocking matrix preprocessing(BMP)and based on eigen-projection matrix preprocessing(EMP)are discussed in this thesis,and verifying the effectiveness of these algorithms in suppressing mainlobe jamming.But these two algorithms have the problem of beam pointing offset.To solve this problem,this paper introduces three directional pattern conformal methods,namely weight compensation,diagonal loading and whitening processing.At present,there is no mature angle measurement scheme for BMP algorithm and EMP algorithm.At last,the angle measurement of projectile-borne array radar under mainlobe jamming is studied deeply.The four-channel mainlobe jamming suppression monopulse angle measurement technique can suppress mainlobe jamming well and realize the angle estimation of the target.However,this algorithm is no longer applicable in the environment of mainlobe and sidelobe jamming.To solve this problem,an adaptive monopulse angle measurement algorithm based on the eigen-projection matrix preprocessing is proposed in this paper.In the algorithm,first of all,with eigen-projection matrix preprocessing filter out jamming noise sampling the mainlobe jamming of sample,and then rebuilt after preprocessing of the covariance matrix,and the covariance matrix calculation of reconstruction level submatrix constraint adaptive beamforming weights,then unavailability value of array receiving the echo signal of weighted summation,formed has four channels to restrain the sidelobe interference system.Finally,the four-channel mainlobe jamming suppression monopulse angle measurement technique is used for the signals in the four channels.Simulation results show that the proposed algorithm can suppress jamming signals and achieve good performance of target angle estimation when the mainlobe jamming and multiple sidelobe jamming exist simultaneously.