Research On Radar Jamming Suppression Based On Jamming Cognition

The classical radar jamming suppression technology uses the difference between the target and the jamming signal in time domain,frequency domain or spatial domain to suppress by pulse compression,frequency domain filtering or sidelobe cancellation.With the rapid development of DRFM(Digital Radio Frequency Memory)technology,a variety of new coherent interferences are emerging.It is difficult to suppress different interferences in one way.Based on the recognition of the new jamming,it is a research hotspot of radar jamming suppression technology to study the targeted jamming suppression algorithm,so as to improve the jamming suppression detection performance of radar.Aiming at the intermittent sampling and forwarding jamming and smart noise jamming,this paper studies the jamming cognitive method,adopts the jamming suppression method based on jamming reconstruction cancellation and transform filtering to effectively suppress the two kinds of jamming,and designs and realizes the radar jamming simulation system based on jamming cognitive.The main work is summarized as follows.(1)Based on the analysis and modeling of intermittent sampling repeater jamming and smart noise jamming based on DRFM,CFAR based detection and parameter rough estimation of radar echo with jamming are carried out.After interference detection,deep learning method is used to recognize intermittent sampling and forwarding interference,smart noise interference and other types of interference.The recognition rate reaches99.26%,which provides support for accurate interference cognition.(2)The existing intermittent sampling repeater interference parameter estimation is mainly based on Hilbert Huang transform,which has the problem of insufficient accuracy of interference sampling period estimation.In this paper,the joint estimation method based on fuzzy function and HHT is used to improve the cognition of interference.Compared with HHT method,JSR can be reduced by 3 to 6dB.(3)According to the characteristics of both coherence and randomness of smart noise interference,firstly,the interference is preprocessed by beat processing and frequency domain filtering,which can eliminate part of the interference signal.Then,by acquiring the prior information of jamming and radar transmitting signal,the residual jamming is eliminated by narrowband filtering in FRFT domain.In the results of pulse compression processing,after the improvement of beat pre-processing,it shows that the residual peak formed by the above processing is 5 to 8 dB smaller than that of the interference signal filtered directly in FRFT domain.(4)The generation,detection,identification and suppression methods of the above jamming signal are integrated.Through the development of radar jamming suppression simulation software interface in MATLAB software app designer platform,three modules of jamming signal simulation,data processing and identification and jamming suppression are designed,which are convenient and flexible for jamming suppression simulation test.