Research On Radar Mainlobe Jamming Suppression Algorithm

The electromagnetic environment in the battlefield environment is becoming more and more complex,especially when the mainlobe jamming exists,which seriously affects the normal working performance of the radar.In order to solve this problem,this paper focuses on the mainlobe jamming suppression algorithm of radar.The main research work and innovations are as follows:Firstly,the radar mainlobe jamming suppression algorithm based on blocking matrix is studied.Firstly,the reasons of beam offset and mainlobe direction distortion caused by traditional blocking matrix mainlobe jamming suppression methods are analyzed.Then,LCMV algorithm based on quadratic inequality constraint is proposed to solve the mainbeam offset caused by beam formation.The Lagrange multiplier method is used to solve the constraint equation of quadratic inequality.Secondly,Radar mainlobe jamming suppression algorithm based on feature projection matrix.Aiming at the inherent defect of blocking filter based anti-mainlobe jamming method in the previous content,the method of reconstructing the covariance matrix of received data to realize radar mainlobe jamming suppression is studied.Firstly the features of projection matrix algorithm and the projection matrix and covariance matrix reconstruction algorithm are introduced,and analyses the advantages and disadvantages of the algorithm,to raise the sidelobe level of the above algorithms as well as in the case of steering vector mismatch problem such as anti-jamming performance degradation,improved algorithm based on EP-CMR algorithm is proposed,by using the constraints of the sidelobe level and target signal direction method of weighted value is optimized with constraints,through the simulation can be seen that the improved algorithm improve the above problems and beamforming robustness are improved.Thirdly,the method of waveform design is studied to realize radar mainlobe jamming suppression.First to Frank coding and properties are introduced,and then to use Frank coded radar,the principle of mainlobe jamming resistance are analyzed,mainly by using the orthogonality of the Frank orthogonal design with the target signal blocking filter,will get the signal as the auxiliary channel blocking filter and the matched filter signal as the main,the use of adaptive jamming cancellation algorithm will auxiliary channel and noise cancellation,achieve the goal of mainlobe jamming.However,this algorithm will lead to the rise of the distance sidelobe in the presence of large targets.Aiming at this problem,an improved method is proposed to solve the problem of range sidelobe level rise by replacing the data of the distance-doppler unit where the target signal is located with the weighted value calculation.