Research On Against Active Deception Jamming Of Waveform Agile LFM Pulse Radar

The active deception jamming based on digital radio frequency memory technology makes it difficult for linear frequency modulation(LFM)pulse radar to distinguish the true and false targets,which becomes an urgent problem in radar against jamming.This kind of deceptive jamming can be divided into conventional deceptive jamming and dense false target jamming.The conventional deceptive jamming includes range jamming and speed jamming.Dense false target jamming,which is both suppressive and deceptive,is a new type of jamming,which brings severe new challenges to LFM pulse radar.In this paper,based on the waveform diversity technology,combined with the dictionary learning method of multi domain separation technology,the separation of jamming and target is realized.The main contents of this paper are as follows:Firstly,aiming at conventional range deception jamming,an active deception jamming detection method based on the initial phase waveform diversity between pulses is proposed.According to the phase difference between target and jamming signal,the peak detection method is used to estimate the phase difference of the compressed peaks of adjacent periodic signals,which not only realizes the jamming detection but also obtains the period of the jamming lagging transmitted signal.Then,an agility LFM signal of random initial phase combined with slope-varying anti-range deception jamming method is proposed.Based on the orthogonality of the signal,the jamming of weaker energy can be effectively suppressed,and the prior information obtained by the peak detection method combined with the amplitude limiting method can further combat the jamming of the stronger energy range false target.Secondly,aiming at conventional speed deception jamming,a dual-channel processing parameter estimation method is studied.The estimated Doppler information of the jamming signal can be used as a priori knowledge for anti-jamming research.Then,a power spectrum template-based waveform design method for anti-speed deception jamming is proposed.Using the jamming energy minimization criterion,the power template method is used for adaptive waveform design,and the stopband formed under the Doppler spectrum can achieve real target detection.Finally,an anti-speed deception jamming method based on adaptive dictionary is proposed.The quasi Karhunen-Loeve transform(Q-KLT)basis of the jamming signal is established based on the prior information,the approximate Q-KLT basis of the target echo is constructed through the dictionary learning method.The base tracking algorithm is used to realize the separation and recovery of the target and the jamming,and achieve the purpose of suppressing the high-power speed deception jamming.Thirdly,aiming at the jamming of dense false targets,a method of anti-dense false target jamming based on the correlation characteristics of the orthogonal frequency division LFM waveform is proposed.The low cross-correlation characteristics between the designed orthogonal frequency division LFM signal and the repeating jamming signal can effectively suppress the dense false target jamming.Then,in order to further reduce the sidelobe jamming,an anti-dense false target jamming method based on waveform design and dictionary learning is proposed.Design a phase perturbation LFM(PPLFM)signal with low autocorrelation sidelobes through the optimization algorithm,and construct the target initial dictionary and the jamming initial dictionary with the correlation functions of the radar signal(optimized PPLFM signal)with different distance dimension information.The dictionary learning method is used to establish the approximate Q-KLT basis of the target and the jamming signal,so as to achieve the suppression of the dense false target jamming.