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Research On Reconnaissance Technology Of Frequency Modulated Continuous Wave And Quasi Frequency Modulated Continuous Wave

Posted on:2017-05-11Degree:MasterType:Thesis
Country:ChinaCandidate:Y L JianFull Text:PDF
GTID:2308330485988045Subject:Electronic and communication engineering
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Modern electromagnetic environment become more and more complicated. Because of the low intercepted, no distance blind spots and simple structure, frequency modulated continuous wave has been widely used in modern electronic countermeasure system. On the other side, the characteristics of quasi frequency modulated continuous wave is high repetition frequency, approximating to a continuous signal. This caused a certain difficulty for electronic reconnaissance and challenges. The research on the detection, identification and parameter estimation of frequency modulated continuous wave and quasi frequency modulated continuous wave become more and more important and has great research significance. Based on the environment of electronic reconnaissance, around the detection, identification and parameter estimation of frequency modulated continuous wave and quasi frequency modulated continuous wave, the main work is as follows:1. The detection and recognition of the frequency modulated continuous wave and quasi frequency modulated continuous wave are studied in view of the situation that the existing reconnaissance system can receive many kinds of signals. For different modulation continuous wave, this thesis analyzes all kinds of frequency modulated continuous wave and quasi frequency modulated continuous wave’s characteristics. Study on the recognition algorithm of frequency modulated continuous wave and quasi frequency modulated continuous wave, pulse radar and communication signals. For the frequency modulated continuous wave, the recognition algorithm of the STLFMCW and SLFMCW, SFMCW and SQFMCW are studied.2. There are abundant study on the LFMCW’s parameter estimation, but NLFMCW’s parameter estimation is less studied. For this situation, this thesis studied on the parameter estimation algorithm for linear and nonlinear frequency modulated continuous wave. Improving the estimation performance of linear frequency modulated continuous wave. At the same time, the parameter estimation of nonlinear frequency modulated continuous wave is solved. In view of the LFMCW, first of all, based on the method of FFT to estimate the modulation cycle. Then based on the cyclic autocorrelation and line adjustment method estimates the frequency modulation slope. Finally, based on the conjugate matching algorithm to estimate its initial frequency. If the signal is STLFMCW, before its parameter estimation, we should transform it to the SLFMCW. If signal is NLFMCW, first of all, estimating the modulation cycle based on autocorrelation method. Based on the line adjustment, we can get the bandwidth and initial frequency of SFMCW. In view of the SQFMCW, using line adjustment method to estimate the bandwidth, finally based on conjugate matching method estimate the initial frequency.3. In view of the current parameter estimation method of the quasi frequency modulated continuous wave is less studied, the parameter estimation algorithm is studied in this thesis. After studying the traditional FRFT and FRFT’s characteristics of LFM, improving the kernel function of FRFT to fit the quasi frequency modulated continuous wave. We get the PFRFT in this way and analyzed the characters of quasi frequency modulated continuous wave’s PFRFT. Complete the parameter estimation of quasi frequency modulated continuous wave, including cycles, bandwidth, initial frequency and duty ratio. Solved the problem of quasi frequency modulated continuous wave in parameter estimation.
Keywords/Search Tags:frequency modulated continuous wave, quasi frequency modulated continuous wave, detection and recognition, parameter estimation
PDF Full Text Request
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