Research On The Anti-jamming Technology For Radar About DRFM Jamming

With the development of digital radio frequency memory(DRFM) technology, deception jammers mainly use repeater deception jamming technology. As long as the modulation parameters of the repeater signal can be normally processed by radar, it can also obtain the radar signal processing gain. So this deception jammer can greatly reduce the demand for jamming power of the jamming signal, especially be suitable for the jamming of the radar system using coherent signal processing technology. DRFM can produce false targets, multiple false targets, shift- frequency jamming, interrupted-sampling DRFM jamming and so on. The jamming effect on radars of deception jammers has been increasing greatly, which has put forward a great challenge on subject of radar anti-jamming.In this case, firstly this thesis makes the detailed research on the anti-jamming technology for radar about DRFM jamming.Based on the study of radar pulse compression system model and the characteristics of DRFM, the whole process of radar anti-jamming in general can be divided into in-pulse anti-jamming and inter-pulse anti-jamming. Based on time sharing processing of DRFM jammer’s receiver and transmitter, a multiple pulses radar signal is proposed. Multiple matched filters are designed and set in radar receiver.Through the number of threshold-crossing goals,true and false targets can be detected. In the thesis, Section phase modulated LFM, N LFM in pulse and phase coded among pulses signal are analyzed, which can cause interference signals and radar signals to mismatch. The proposed signals possess strong autocorrelation and weak cross-correlation properties.Then based on the characteristics of digital sample DRFM technology, the method of the co mplex waveforms design on anti-digital sample DRFM is analyzed.Finally,a method based on orthogonality principle and pulse diversity technique is given. This method applies to enemy targets ahead of the jammer and preceded false targets jamming of DRFM.