The Target Detection Method Against Main-Lobe Multi-Point Source Interference/Variable Polarization Interference

With the gradual development of modern electronic warfare,the battlefield electro-magnetic environment faced by radar is becoming ever complex.The cooperative penetration with escorted jamming,self-screening jamming and stand-off jamming et al.greatly increase the probability of introducing multiple signal sources in the main-lobe of the radar antenna.Combining the “main-lobe” and the “multiple-sources”,the difference between the jamming signals and the target echo in the fields of time,frequency,space and polarization decrease,usual radar electronic counter-countermeasures become invalid.As another important information field except for the fields of time,frequency and space,polarization is closely related to the improvement of radar anti-jamming performance.However,with the development of jamming technology,variable polarization interference has been applied in active servic e at home and abroad as well as in the new generation of jamming equipment,which becomes another difficult issue for radar target detection.Based on the polarization characteristic differences between multi-point source interference,variable polarizatio n interference and target,this paper focuses on the radar target detection method and its ability analysis in the background of "main-lobe multi-point source interference/ variable polarization interference".The main content of this paper can be divided into three aspects:1.Ability analysis of existing methods against main-lobe multi-point source interference/ variable polarization interference.Firstly,the basic principle of joint filtering of polarization-spatial domain and the target detection method based on joint spectrum estimation of polarization and space is introduced.On this basis,the interference suppression performance or target detection ability of the two methods in different cases of main-lobe multi-point source interference/ variable po larization interference are analyzed.And the limitations of the two methods against the main-lobe multi-point source interference / polarization interference is revealed.2.A target detection method for polarimetric radar based on uniform phase diversity.Aiming at the defect that the original target detection method has high misjudgment rate in the background of multi point source interference and variable polarization interference,radar transmit polarization diversity method is further designed,the polarization state distribution difference between target and jamming is extracted,and the target detection method based on polarization divergence feature and polarization distribution feature is proposed.The performance of the original detection method and the improved method are compared by simulation,the result verified the effectiveness of the proposed method against the main-lobe multi-point source interference/ variable polarization interference.3.The influence of non-ideal factors on target detection performance.Firstly,the statistical model of the influence of the amplitude-phase error of the array antenna channel on the angle estimation error of the polarization spatial joint spectrum is derived.On this basis,the effect of channel amplitude and phase errors on target detection performance is improved by simulation.Secondly,the influence of non-equal power signal on the resolution of joint spectrum estimation of polarization and space is studied.Finally,the influence of non-equal power factor on the performance of target detection is analyzed.