Research On The Methods To Realize Mainlobe Anti-jamming In Tracking Radar

When tracking radar performs remote target detection,the interferences around the target will mainly fall into the mainlobe of antenna,and high-level interference signals will cover weak target.Even if the source of interference is more than several kilometers away from the target,it will have a bad impact on the detection effect of radar.Therefore,it is necessary to suppress mainlobe interference of tracking radar.The focus of this paper is the algorithm and engineering implementation of subarray-level mainlobe anti-jamming based on largeaperture planar array.Relying on the signal processing system of tracking radar,an improved subarray-level mainlobe interference suppression method is proposed in this paper,in combination with the constraint of mainlobe subspace and the linear constraints of sidelobe interferences.It has a more stable performance of mainlobe interference suppression under complex electromagnetic background.Based on the modeling of narrow-band array echo,this paper first introduces the basic theory of subarray beamforming.Aiming at the problems caused by uniformly adjacent subarray partitioning method,an array design configuration based on the optimal degree of freedom is proposed.The optimized array structure has a higher degree of adaptive freedom,and avoids the problems of grating lobe and grating null.Simulation results prove its advantages in regard to beamforming stability.In terms of interference confrontation,different criteria for solving adaptive weight vector are explained.In addition,the suppression principle of subarray-level adaptive digital beamforming is mainly studied,and the target reception loss caused by mainlobe interference is mainly simulated and analyzed.Aiming at the space confrontation of strong mainlobe interference,three sub-array processing methods based on eigen-projection are studied in this paper.In consideration of the mainlobe peak shift caused by eigen-projection and the shallow sidelobe notches caused by strong mainlobe interference,a subarray-level mainlobe interference suppression method based on tracking radar system is proposed in this paper.This method uses Akaike information criterion and correlation discrimination to distinguish interferences,and combines with the constraint of mainlobe subspace and the linear constraints of sidelobe interferences.Therefore,by defining a new way of weight vector shaping,this method can effectively overcome mainlobe distortion,and still maintain outstanding interference suppression effect under strong mainlobe interference and less sample.Simulation results show that the proposed method achieves a more robust pattern preserving effect,obtains a notch gain close to the ideal zero value of each interference,and improves the output signal to interference plus noise ratio by more than 1.3d B.In terms of algorithm implementation,based on the signal processing experimental platform of tracking radar,this paper discusses the implementation plan of system from top to bottom.Based on the TMS320C6678 multi-core DSP system,the parallel processing of the mainlobe interference suppression algorithm proposed in this paper is realized.Meanwhile,the function modules of system and the communication of SRIO are verified by digital source signals.In addition,the feasibility and superiority of the proposed algorithm in interference suppression engineering are also analyzed and proved.