Deceptive Jamming Suppression With Waveform Diverse Array Radar And Processor Design And Implementation

Modern radar systems are facing increasingly complex electronic jamming environment,in which deceptive jamming,especially main lobe deceptive jamming,is very similar to target signals in time,frequency,polarization and other dimensions,inducing radar systems to treat jamming signals as real target signals,which seriously affects detecting and tracking of real targets by radar.It's a major chal enge to the power and viability of radar system,and it is also a problem of anti-jamming at present.Aiming at the problem that active main lobe deception jamming is difficult to suppress in complex electronic environment,this thesis studied the main lobe deceptive jamming suppression method of waveform diverse array radar,and designed the experimental system.The main work can be summarized as follows:1.Based on the frequency diverse characteristic of frequency diverse array at the transmit ter,the pattern characteristics of continuous wave and pulse wave are analyzed in detail.Firstly,introduced the basic concept of frequency diverse array and the signal model.Secondly,studied the characteristics of the pattern when transmitting continuous wave signal.In this situation,the pattern is time-varying and shows periodicity in the distance dimension.In order to solve the problem of multiple main lobes due to range periodicity,the transmit signal is modulated by pulse,so that the pattern will be in quasi-steady state.The effective range is related to the duration of the pulse.On the basis of transmitting coherent signals,further consideration is given to beamforming the echo signal at the receiver to obtain the joint transmit-receive pattern,which has directivity when the angle is determined.The simula t io n results show that the frequency diverse array radar can realize joint range-angle parameter estimation.2.Searching for the characteristic of main lobe deceptive jamming signal,signal model and space-time-frequency multi-dimensional feature analysis under different radar systems are carried out.Firstly,the main steps of deceptive jamming generated by digital radio frequency memory technology are given,and the process to achieve distance deception is analyzed,the equivalent expression of jamming is given based on the form of target echo signal.The multidimensional spatial characteristics of main lobe deceptive jamming are simulated under different radar systems.The following characteristic is found: FDA-MIMO radar has rangeangle coupling characteristic,and the delay distinction(range distinction)between main lobe deceptive jamming and true target echo is reflected by coupling characteristic to the equivalent transmission angle distinction,so FDA-MIMO radar can distinguish them in transmit-receive dimension.On this base,two-dimensional beamforming can be used to suppress jamming.3.Aiming at the problem of the random distribution of the distance dimension of the main lobe deceptive jamming signal,which makes more difficult to select the deceptive jamming samples and influence the performance of the interference covariance matrix estimation,a method combined the subspace projection of receiving the direction of the main lobe with the detection of signal power is proposed to select the jamming samples.Firstly,through FDA-MIMO radar transmitting frequency diverse signal,and matched filtering the received echo data.Secondly,compensating received echo data in the distance.Thirdly,based on the subspace projection technique,constructingn the received main lobe direction subspace,obtaining the echo signal power in the main lobe direction,and selecting samples using the power detection method.This method improves the performance of estimation of jamming covariance matrix.Lastly,the deceptive jamming can be successfully suppressed in transmitreceive frequency domain by beamforming technology under the condition of some prior knowledge.The feasibility of anti-main lobe deception jamming of FDA-MIMO is achieved.4.On the waveform diverse array radar test system,designed and implemented the receiving data transmission and memory subsystem.The data transmission and memory subsystem is mainly composed of multi-channel receiving processor,optical fiber receiver and server computer.Firstly,a two-stage cascaded FIFO data buffer module is designed to complete bit-width conversion in order to solve the problem that the receiving processor receives too much data and the data bit-width is much larger than the transferable bit-width.Secondly,the maximum sample number is estimated according to the hardware configuration conditions of the system,aiming at the problem of data interleaving in bit-width conversion.The data is added with instructional information for subsequent data analysis,and then the integrated data is transmitted to the optical fiber receiver.Finally,the data is stored to the server by the memory software.Hardware test results show that the subsystem can accurately memory data.This thesis gradually extended the simulation analysis and demonstration in theory into the actual verification of the experimental system.In theory,this thesis provided a better solution to the problem of difficult suppression of main lobe deceptive jamming,it can be used to suppress the jamming of drag-type decoys,interference pods and ship-assisted decoys,bee colony drone.In actual,the test system not only realizes the ability of waveform diversit y array radar to suppress main lobe deceptive jamming,but also lays a foundation for the practical application of radar communication integration,active jamming location and spacetime coding array technology.