Distributed Electronic Reconnaissance Preprocessing

This thesis will study the related technologies in the distributed electronic reconnaissance preprocessing system,build a complete digital signal preprocessing system,and try to improve related technologies.In the preprocessing system,the intercepted radar pulse signal is decomposed and processed,and the calculated basic parameters of the radar pulse are formed into pulse description words(PDW),which provides data support for the subsequent main processing,and compress the data for the estimation of the pulse time difference of arrival(TDOA)required for distributed positioning in the later stage.The key technologies of electronic reconnaissance preprocessing mainly include: digital channelization technology,estimation of basic parameters of radar pulses,and data compression in TDOA estimation.This thesis will take the distributed electronic reconnaissance pre-processing system as the research object,study the key technologies in it,and perform MATLAB simulation,behavioral simulation verification and FPGA implementation on it.The main work includes the following aspects:1.Research the digital channelization technology that widely used in distributed electronic reconnaissance systems,and carry out MATLAB simulation and FPGA implementation of its improved structure.Research a new type of signal decomposition algorithm,Variational Modal Decomposition(VMD)algorithm,because of its ability to track signal frequency autonomously,it is more flexible to use,and try to use it to replace the traditional digital channelization algorithm.The algorithm is simulated in MATLAB to study the performance of the algorithm in terms of accuracy of decomposition results and signal-to-noise ratio.Aiming at the characteristics of the electronic reconnaissance field,the algorithm is improved,and its feasibility in the field of electronic reconnaissance is verified.2.Research the data compression technology of TDOA estimation in distributed electronic reconnaissance system.Distributed TDOA positioning uses TDOA that intercepts signals between multiple aircraft in reconnaissance to locate targets.However,due to the limited bandwidth and data transmission rate between multi-aircraft communications in the distributed reconnaissance network,the accuracy of the TDOA estimation results is limited.In order to solve this technical difficulty,this thesis introduces the idea of compressed sensing,research a TDOA estimation technology based on data compression to solve these problems,and carries out MATLAB simulation and FPGA implementation of the new technology,and applies it to actual engineering.3.Research the method of extracting basic parameters of radar pulse in the distributed electronic reconnaissance signal preprocessing system,which is used to obtain the received signal frequency,pulse arrival time,pulse width and pulse repetition period and other parameters,and these obtained parameters are packaged as PDW and sent to the host for subsequent data fusion,signal sorting,interference identification and other main processing processes.