Research On Adaptive Jamming Waveform Technology Of Phased Array Radar

Modern warfare has long become a high-tech war,the field of electronic countermeasures as its core part has been able to produce the effect of influencing the war situation,radar as an important equipment of electronic countermeasures,its research and application has been widely concerned.Compared with traditional mechanical scanning radar,phased array radar because of its high data rate,versatility,high flexibility and high reliability,has been more and more widely used in the battlefield,has become a very important one of many radar types,therefore,the study of the interference problem for phased array radar has become more and more important,especially according to the change of the battlefield environment can adaptively generate interference waveform algorithm is also more and more concerned.This thesis mainly focuses on the two typical smart jamming methods of intermittent sampling forwarding interference and convolutional interference,to study the adaptive interference waveform generation technology of these two methods,and evaluate the interference effect of the generated interference waveform through the number of false target points and SJNR.The specific research content is as follows:(1)In response to the STFT method to suppress intermittent sampling and reposting interference,it proposed a targeted countermeasure using the reorganization method.The intermittent sampling and forwarding interference wave shape was designed by the restructuring method,so that it cannot know the cycle of intermittent sampling signals based on the STFT method,so as The sampling signal cannot be reconstructed to achieve the purpose of intermittent sampling and interference waveform design.(2)Analyze the distribution characteristics of false targets generated by each forwarding order of intermittent sampling and forwarding interference,propose the use of superposition method to design the interference waveform,by changing the parameters of the sampled signal,make false target groups superposition each other,so as to produce more false targets with higher amplitude,and carry out target detection on the interference signal echo through CFAR.The number of detected false target points is used to evaluate the effect of interference,and again on the basis of studying the effect of superposition method applied to intra-pulse frequency coded signal and nonlinear frequency modulation signal,and the detection results of CFAR are used to evaluate the effect of interference.(3)When the radar receiver is used to detect the target,the larger the SJNR of the echo signal is,the greater the probability of detecting the target will be.Through the process analysis of the system,with minimizing SJNR as the objective function,under the condition of a certain power limit of the radar transmitter,considering the environmental interference and characteristics of the radar transmitted signal,Through modeling and solving,the waveform of the convolution interference signal of the optimal power spectrum is obtained,and further considering that the peak-average ratio of the interference signal will have a negative impact on the signals transmitted by the jammer,SLM algorithm and limiting method are used to reduce the peak-average ratio of the convolution interference signal,and the differences produced by different limiting thresholds are compared and analyzed.Finally,the decrease of SJNR amplitude and detection probability of the interference signal designed by the optimal power spectrum is compared to evaluate the effect of interference.