Radar Active Jamming Recognition Methods And Efficient Implementation

In the modern battlefield,the missile-borne composite radar system can guide missiles to attack enemy targets more accurately,at the same time,all kinds of jamming produced by enemy's jammers are affecting missile-borne composite radar system' normal working.With the development of jammer technology in recent years,active suppression jamming and active deception jamming pose a serious threat to missile-borne composite radar system.Therefore,we need to identify active jamming to ensure the normal operation of missile-borne composite radar system.By fully utilizing the prior information provided by cooperative radar and combining the data of broadband receiver and narrowband radar receiver,the identification method of active jamming is studied.This thesis also finishes the hardware implementation.The main work of this thesis is summarized as follows:1.The way missile-borne composite radar obtains target information are given.And the types of active jamming that aims at missile-borne composite radar is analyzed.2.The spectrum difference of different types of active suppression jamming is analyzed.Firstly,the spot jamming is identified by analysing the number of cross-channel.Then,the blocking jamming and sweeping frequency jamming are identified by analysing the relationship between the occurrence time of jamming and channel number of jamming,and the simulation results are given.Because the purpose of identifying suppressed jamming is to guide cooperative radar to work in uncovered frequency bands,for calculating the interference bandwidth accurately,the FFT decomposition algorithm of super-long points is studied.3.For range deception jamming.Firstly,the irrelevant signals are eliminated.Then,If the received signal has the same type and parameters as the radar transmitting signal,but its pulse width is narrower,it is considered as partial pulse direct forwarding jamming.Partial-pulse repeated forwarding jamming is identified by pulse compression ratio.And full-pulse repeated forwarding jamming is identified by the number of spikes after pulse compression.Analyze time of arrival(TOA)in multiple pulse repetition interval(PRI),it is considered to be echo if all the TOAs are same,it is considered to be range-gate pulloff jamming if the TOAs' change is regular.4.For velocity deception jamming.Firstly,the method of signal detection under low signal-to-noise ratio(SNR)and low jamming-to-noise ratio(JNR)using Haar wavelet transform is researched.Then,by using spectrum difference and Rayleigh distribution fitting,the recognition method of echo and jamming is proposed.By checking whether the peak position of slow time domain changes,speed false target jamming and velocity-gate pulloff jamming are identified.5.The overall architecture of the hardware system is described,the development environment and communication interface are introduced.The efficient implementation of algorithm based on multi-core DSP is analyzed.Then,the method of optimizing program is put forward.Finally,the results of hardware debugging are given.