Study On ISAR Jamming Technology Based On Phase Modulation

Inverse Synthetic Aperature Radar(ISAR),as one important part of the advanced imaging radars,is capable of acquiring the high-resolution two-dimensional images of moving targets and plays an important role in many military applications,such as target classification and recognition,missile homing guidance and battlefield situational awareness et.al.Due to its all-day and all-weather two-dimensional high-resolution imaging capability,it poses a serious threat to the penetration of missiles,ships,combat aircraft and other important targets.Therefore,it has been a research hot topic that how to effectively jam ISAR and destroy its target recognition capability in the field of electronic countermeasures.Focusing on the existing problems and shortcomings of ISAR jamming,this paper takes protecting important target penetration as the application background,takes ISAR active jamming as the entry point,takes theoretical derivation and experimental simulation as the technical means,and deeply studies the ISAR jamming method based on phase modulation.The main research contents are as follows:Firstly,based on the characteristics of phase modulation sequence,a two-dimensional ISAR jamming method based on periodic binary-phase modulation is proposed.The main researched contents include the high-resolution range profile(HRRP)jamming algorithm and two-dimensional ISAR jamming algorithm.The characteristics of the periodic binary-phase sequence both in time domain and frequency domain are analyzed in detail.The matching filter properties of phase-modulated echos are addressed.The expression of target HRRP deceptive jamming is induced and the relationship between phase modulation parameters and the distributions,number and amplitudes of false targets is discussed.Based on the principle of scattering wave modulation,the scatter wave jamming and periodic binary-phase modulation are adopted in ISAR two-dimensional jamming.The modulation process is applied both in the fast time domain and slow time domain.The jamming model is estabilished and the jamming signal imaging expressions are deduced.The time-frequency distributions of jamming signal are studied.After ISAR imaging prosessing,the down-range strip jamming,the cross-range strip jamming,the two-dimensional barrage jamming and the false targets deceptive jamming are obtained.Then,the jamming effects are evaluated based on the correlation coefficient.Finally,the computational complexity of the phase modulation jamming method proposed in this chapter is compared with that of other jamming methods.The results show that the proposed method greatly reduces the computational complexity.Secondly,based on digital image synthesis technology,an improved phase modulation coefficient digital image synthesis technology jamming method is proposed.The main research contents are: the improved method of alternating changing phase modulation coefficient sign according to the odd-even property of range cell and the digital image synthesis method based on periodic binary-phase modulation.The digital image synthesis scheme with improved phase modulation coefficient is presented,and the mathematical expression of the output of digital image synthesizer is derived.Bring periodic binary-phase sequence into the phase samples and inter-pulse phase modulation of intercepted ISAR signals,the mathematical basis of generating multiple false targets is analyzed theoretically,and the false target deceptive jamming effect is verified by simulation.Finally,based on convolution modulation jamming,an ISAR jamming method comaining one-bit sampling and convolution modulation is proposed.Starting from the principle of one-bit sampling,the mathematical principle of one-bit sampling is introduced in detail,and the characteristics of one-bit sampled signal are discussed.The mathematical principle of convolutional modulation jamming is presented,and it is pointed out that deceptive jamming or barraging jamming can be produced according to the choice of video signals involved in convolution.Then,the mathematical derivation of one-bit sampling combined with convolution modulation jamming is presented,and the expression of jamming signal is obtained.Finally,the false target template is selected to simulate the deceptive jamming and barrage jamming respectively,and the jamming effect is determined based on the correlation coefficient,which verifies the correctness and effectiveness of the proposed method in this chapter.