Research On Wideband Radar Coherent Jamming Based On Intermittent-sampling Repeater Jamming

High resolution is the development trend of modern radar development. By emittinglarge bandwidth-time product radar signals, wideband radar can obtain space position andmovement feature of targets, and get high resolution one-dimensional or two-dimensionalfeature, which means wideband radar has a powerful battlefield cognitive ability. How tojam wideband radar has become a heating new subject in ECM area. Intermittent-SamplingRepeater Jamming (ISRJ) is a novel coherent jamming method, but its research onwideband radar systems is in the primary phase. Based on this background, coherentjamming methods of wideband radar are systematically and profoundly studied in thisdissertation.Chap1illustrates the background and significance of this research subject, andintroduces the present status of wideband radar ECM techniques, including wideband radarsystem and jamming techniques. The development trend and existing problems ofwideband radar jamming techniques are especially analyzed. The present status ofIntermittent-Sampling Repeater Jamming (ISRJ) is further summarized. The majorresearch efforts of this dissertation are also explained.Chap2introduces the basic principles of DRFM (Digital Radio Frequency Memory)and ISRJ. Then the characteristics of sampling signal and the sampled radar signal isanalyzed. The basic principles of direct repeater, repetitive repeater and circular repeaterare introduced.Chap3studies one dimensional coherent jamming on wideband radar system. TheISRJ jamming effect on LFM, Step Frequency and phase coded signal is analyzed. Twokinds of jamming method based on Intermittent-Sampling and repetitive RepeaterJamming are proposed: the jamming method on Step Frequency signal based onIntermittent-Sampling and Repetitive Repeater Jamming and the jamming method onphase coded signal based on Intermittent-Sampling and Rrepetitive Repeater Jamming.The group delays characteristics of phase-coded match filter are analyzed to explain whyshift-frequency repeater jamming and ISRJ can’t form precede false targets. Then, a noveljamming approach of forming preceding false targets to phase-coded radar by partialreceiving and predictive repeater is presented. The requirement for repeater power isanalyzed. Theoretical analysis and simulation results show that the new jamming methodcan form precede false targets and does not have rigid requirement for power. So, thismethod has potential value in practice.Chap4studies two dimensional coherent jamming on wideband radar system. Afterintroducing the theory of ISAR, the present status of ISAR jamming is presented. Then,based on ISRJ, a novel generation method of2-D ISAR group targets is presented. In thismethod, escort free-flight jammer is used to intermittently sample and repeater target echo, which can generate vivid2-D group targets in ISAR. By adjusting jammer and target’srelative space position,2-D group targets are able to simulate target’s attitude angledynamically. The principle of escort free-flight jamming is introduced. Meanwhile, atheoretical study is carried out to determine the requirement for jammer’s power andposition. Then, the theoretical reason of2-D group targets is emphatically analyzed.Moreover, The key factor of false targets distribution and attitude angle is explored. At last,the simulation demonstrates that the above method is effective. The results obtained fromthis research would help to provide better guidance for the design and engineeringapplication of ISAR jammer.Chapter5summarizes the research work and main innovations, and discusses thefuture work to be researched.