Research On Technology Of Anti-active Jamming In Radar

Radar jamming and anti-jamming are a pair of irreconcilable contradictions, and they have been mutual restriction and mutual promotion with each other in the development of modern radar. Essentially, anti-jamming technology retain or enhance the target signal while suppressing jamming using the characteristic difference between the jamming signal and the target signal. On the basis of the achievements obtained by now, the corresponding jamming suppression algorithms have been explored through the normal active jamming and active additive compound jamming suppression algorithms in-depth analysis. The main work is summarized as follows:Starting from the generation and mechanism of the active jamming, the signal model including blanket jamming, deception jamming and active additive compound jamming are established according to their features, which provides the basis for the jamming suppression algorithms in this article.The adaptive sidelobe cancellation suppression measure is explored for the blanket jamming, the performance of adaptive sidelobe cancellation system is analyzed on broadband jamming condition, the results show that the algorithm performance will be affected by the correlation of the jamming of each channel and the envelope delays. In order to solve the problem of system performance, we analyse two improvement measures including adding the delay section and increasing sub-band filter group to the sidelobe cancellation system in the third chapter. The simulation showes that the extent of the sidelobe cancellation performance improved by adding the delay section depends on the delay time of the delay section, the shorter the delay, the greater the improvement in sidelobe cancellation performance. The cancellation performance of system is increased as the number of sub-band filter group increases.Conventional pulse compression radar transmitting the same coherent pulse train in the different pulse repetition period under this radar system, the sidelobe blanking algorithm is studied for the deception jamming. The algorithm suppress the jamming in one or several distance units according to the jamming signal amplitude difference between main antenna and auxiliary antenna. The simulation showes that the sidelobe blanking algorithm can suppress the deception jamming effectively. However, for the waveform agility radar, it transmitting different waveforms in different pulse repetition period. For this radar system, the algorithm of variable pulse compression is studied for the deception jamming. The algorithm suppress the jamming via the orthogonality between the jamming signal and the target signal. Therefore the design of orthogonal waveforms group method is explored in the fouth chapter, meanwhile the effect of time-varying pulse compression suppress the deception jamming is simulated, the result shows that the algorithm can supress the deception jamming effectively for this radar system, and it can eliminate the jamming without loss of the target energy.Last, the step to step suppression algorithm for the active additive compound jamming is studied. Take attention to the active additive compound jamming composed by blanket jamming and deception jamming in the time domain. First, suppress the blanket jamming components in the compound jamming using the sidelobe cancellation method, and then process the residual deception jamming from the compound jamming using the sidelobe blanking method. The simulation showes that the algorithm can suppress different jamming components respectivly and improve the target detection performance of radar in complex jamming background.