Design Of Cognitive Waveform And Processing Technology Against Mainlobe Multiple Jamming

As electronic technology continue to develop,the electromagnetic environment becomes more complex.The jamming threats faced by radar systems gradually show a trend from single jamming to multiple jamming.How to make the radar system have the ability to resist multiple compound jamming will also be a problem that has to be considered in electronic countermeasures.This thesis focuses on the suppression of radar mainlobe multiple jamming,and dose the research on cognitive waveform and signal processing and processing technology of radar to resist mainlobe multiple jamming.The main work is as follows:1.The principle of anti-mainlobe multiple jamming based on orthogonal signal is analyzed.A design method of OFDM-NLFM signals is studied,which can effectively suppress the pull off jamming,C&I jamming and intermittent sampling direct forwarding jamming across RPT.2.Under the condition of accurate and inaccurate perception of jamming parameters,a joint waveform and filter optimization design problem is constructed based on the minimization optimization design criteria of the weighted sum of the waveform mismatch filtering output peak sidelobe,the error between waveform mismatch filtering output mainlobe and template and the jamming mismatch filtering output peak level.An iterative L-BFGS algorithm based on cognitive waveform and filter joint design method is proposed,which can effectively suppress the fast forwarding C&I jamming,intermittent sampling direct forwarding jamming and intermittent sampling repeated forwarding jamming.3.A signal transmitting and processing method based on subarray waveform coordination is studied.Under the condition of subarray waveform coordination,the power of signals in different frequency bands reaching the jammer can be controlled.The frequency band signal whose power is lower than the detection threshold of jammer can be used for radar detection,which can effectively suppress the suppressive noise convolution jamming,comb noise frequency modulation jamming and comb noise amplitude modulation jamming.All the above methods against mainlobe multiple jamming are verified by simulation,which show that the above methods can effectively suppress the mainlobe multiple jamming,deal with the complex electromagnetic environment effectively,and realize the target detection.