Research Of Distributed Radar Technology Against Jamming And Target Detection

In the modern warfare,radar plays a key role both in the defense and attack.In a sense,it plays a decisive role to the results of a war.Especially,the deception jamming generated by a Digital Radio Frequency Memory(DRFM)jammer,which resembles the transmitted signal and overlaps the victim radar both in tim e domain and f requency domain,has drawn higher dem and to ECCM.Because of the limitation of monostatic radar’s coverage area and working m ode,distributed radar system has shown advantages as it can transmit different frequency bands by its sepereated radar members.As a result,the distributed radar system has raised broad attention both inside China and outside China.This thesis m ainly deals with active jamming suppression and tar get detection based on the distributed radar system.The contents of this paper are as follows:1.We discussed the characteristics of th e noise amplitude modulation in the tim e domain and frequency dom ain.Its statistical property ha s also been deduced.The mathematical model of the range deception jamming and velocity deception jamm ing was formed.We have shown why t he velocity deception jamming can generate ran ge false targets after pulse com pression through derivation of equations and a mbiguity function of the Linear Frequency Modulation(LFM)signal.2.The m echanism of t he distributed rada r system was studied.The processing results of each monostatic radar was sent to the network center to be further fused.The common three fusion m ethods was introduced.According to the dem ands of different battlefield environments,the radar network would be allo cated in dif ferent spatial distribution forms.And we have also compared their advantages and disadvantages.3.The traditional algorithm to suppress the Noise Amplitude Modulation(NAM)jamming was studied to show that when the carrier frequency of the signal and jamming did not meet certain requirements,the algorithm would lose effectiveness.Based on the traditional algorithm,a new algorithm to cancel the NAM jamming in time domain was presented.The effectiveness and wider sphere of application of the proposed algorithm was proved by num erical simulations.Furthermore,we took advantage of the m any radar members in distributed radar system and the Signal Noise Ratio(SNR)was better because of the coherent integration of the target signal.4.For range-velocity deception jamming,firstly,an algorithm to get the range and Doppler information after the pulse Doppler processing ba sed on the distributed radar system is proposed when there is more than two targets.Secondly,note that the Doppler information of the jamm ing signal would be equal as it was generated by a DRFM jammer,we could use this cha racteristic to determine which one is the f alse target.Thirdly,a further step of decision by taking th e false targets’ range characteristics into consideration was added.This step rea lized the jamm ing suppression and tar get detection in the meantime.