The Implementation And Signal Preprocessing Of Radar Reconnaissance Receiver

Radar reconnaissance receiver intercepts radar signals, and then digitizes the signal to extract the characteristic parameters, and sorting, identification and analysis of pulse characteristics, eventually get radar emitter location and the basic characteristics of information. But the complex electromagnetic environment of modern electronic warfare requires radar reconnaissance receiver which can not only process the sophisticated wideband radar signals, but also intercepts them with full probabilities and perform multi-signal processing simultaneously. The reconnaissance receiver researched and designed in the subject is based on the digital channel technology to achieve the reconnaissance and receiving of wideband signals, simultaneous multi-signal processing,rapid identification and localization of the radiation source. The thesis mainly aims to research and implement the signal preprocessing function of receiver.Firstly, the thesis briefly introduces the previous studies on the radar reconnaissance receiver, and reviews the development of digital receivers, then puts forward the radar intercept receivers based on digital channelized technologies by analyzing and summarizing current conditions of the existing radar receivers. And on this basis, the dissertation systematically expounds the basic conceptions of digital receivers and performs a study on fundamental principles of digital down conversion(DDC) and digital channelization. Then, the digital channelization technologies realized the signal filtering and frequency conversion by replacing the digital down conversion.Immediately following, the thesis presents the efficient implement methods to polyphase filter based on this digital channelization, carries out further deduction and analysis and conducts research and analysis on its principles and structure. Finally, the dissertation unfolds detail deduction and simulation to digital channelization and polyphase filter banks with the use of Matlab tools and carries out its simulation and implementation in FPGA.Secondly, the thesis introduces that the extraction and processing of basic parameters of radar signals involves pulse description words, which mainly includes the phase difference of signal frequency and angle of arrival, the arrival time, the pulse width and so on. The radar intercepts receives process the radar signals, extracts its phase information by demodulating the amplitude phase of signals with the use of CORDIC and then apply them to measure the phase difference of signal frequency and arrival angle. This part of the dissertation mainly discusses the CORDIC algorithm and its simulation and implementation in practices. Then the thesis presents the computation of identical signals’ phase difference and different signals’. The former can be applied for calculating signal frequency. The multiple element antennas receive the same signals and then outputs signals with different phase. By extracting their phase difference, the signals’ angle of arrival can be computed. Meanwhile, channelized signals are conducted threshold detection and forms wide pulsed signals so that the signal’s pulse width and arrival time can be measured. Ultimately, pulse description words(PDW)must be compounded after measuring the whole basic parameters in order to implement the signal sorting and recognition process and pulse feature analysis.Finally, the thesis briefly introduces the fundamental principles of radar reconnaissance receiver and it’s designing and implementing process. It demonstrates the feasibility of the scheme, and illustrates the designing of receiver’s hardware platform and the selection of components. Then dissertation presents the whole signal preprocessing procedure of radar reconnaissance receiver. At last, it makes a summarization on the research and designing of radar receiver.