Research On Anti-mainlobe Jamming Algorithm Of Array Radar

With the development of radar jamming technology,array radars face more and more jamming,which seriously affect the normal operation of radar.The classical adaptive digital beamforming(ADBF)technology can effectively counter the sidelobe jamming signal.But when faced with mainlobe jamming,the use of ADBF technology will lead to the main beam pointing deviation,sidelobe level rise and other problems,which leads to serious decline in anti-jamming performance,affects target detection and direction finding.Therefore,the anti-mainlobe jamming algorithm of array radar is studied in this paper.The main research content is summarized as follows:First the narrow band signal model,receiving signal model of array radar,ADBF technology principle and the concept of the mainlobe jamming signal are introduced.Next the impact of mainlobe jamming on ADBF technology is analyzed.Finally,antijamming performance of several typical anti-mainlobe jamming techniques is analyzed,the direction of the anti-mainlobe jamming study improvement is pointed out,which provides a theoretical basis for the whole paper.Next,it is difficult to estimate the Angle of arrival(DOA)and the amplitude and phase information of target echo signal is destroyed when the typical anti-mainlobe jamming technology is used to counter mainlobe jamming.Aiming at these problems,an anti-mainlobe jamming algorithm based on sparse recovery is proposed.Firstly,the angle atom library is constructed,then the jamming signal is extracted accurately from the received signal by sparse recovery,and finally the jamming cancellation and signal detection are carried out.The simulation results show that the algorithm can not only suppress the jamming signal effectively,but also estimate the DOA,and retain the amplitude and phase information of the target echo.In addition,aiming at the shortcomings of the proposed algorithm in accuracy and speed,two improved algorithm are proposed: improved algorithm based on Alternating Direction Method of Multipliers(ADMM)and improved algorithm based on Lp norm iterative smoothing,the simulation experiments show that the proposed improved algorithm improve the anti-jamming performance of the algorithm on a certain extent.At the same time,the proposed improved algorithm reduces the computational complexity,more suitable for application in the actual scenario.Then,in view of the serious degradation of the anti-jamming performance of the current typical anti-jamming methods when facing with mainlobe adjacent targets suppression jamming signals,an anti-mainlobe jamming algorithm based on oblique projection and atomic reconstruction is proposed.Firstly,the jamming signals are suppressed by oblique projection operator,and then the DOA of target echo signal is estimated and detected signal by reconstructed atoms.Simulation results show that the algorithm improves the capability of radar counter mainlobe adjacent targets jamming signals.In addition,in order to further improve the ability of array radar to counter mainlobe adjacent targets jamming signals,based on polarization sensitive array,an anti-jamming algorithm of spatial-polarization domain joint oblique projection filter is proposed.The DOA and polarization parameters of jamming signals are estimated by joint sparse recovery and maximum correlation principle,and then the jamming is suppressed by the joint oblique projection filter.The simulation results show that the algorithm can further enhance the anti-mainlobe adjacent targets jamming signals capability of radar,and the algorithm can also effectively counter multiple mainlobe jamming signals,with stronger anti-jamming ability.Finally,two anti-jamming algorithms are proposed to solve the problems of signal separation and identification of true and false targets when array radar faces the mainlobe deception jamming signals: 1.In view of the mainlobe frequency-shifting jamming signals,an anti-jamming algorithm based on amplitude comparison and sparse recovery is proposed.Firstly,the sparse recovery method is used to separate the target echo signal and jamming signals,and then the true and false target is identified by the amplitude ratio difference between the echo signal and jamming signals.2.In view of the mainlobe speed-distance deception jamming signal,a joint anti-mainlobe jamming algorithm of double domain is proposed.Firstly,the difference between the ideal delay and the actual delay of false target caused by the modulation resolution of jammer is analyzed.Then,the sparse recovery method is used to separate signals in the spatial domain,and the peak point phase difference sequence of each channel adjacent pulse signal after pulse compression is solved.Finally,the discrete coefficient is used to construct hypothesis test to identify true and false targets.Simulation results show that the proposed algorithm can effectively counter mainlobe deception jamming signals,has high target recognition rate and low false alarm probability.