Research On Detection And Parameter Estimation Of Radar Signal And Its Realization

With the application of Electronic Support Measure (ESM) and the Radar Warning Receiver(RWR), especially the Anti Radar Missile (ARM), the radar can not be contented with themodern war field and its survivability is very low. Low probability of interception radar can usemany kinds of means to avoid its signal intercepting by the interception receiver, and improvesits own survivability. Therefore，research on the methods for detecting and parameter estimationof LPI radar signals is of great significance．Firstly, this paper investigates the low interception principle of LPI radar, expounds therelationship between the low interception performance of the radar and target characteristics,radar characteristics, as well as the sensitivity of reconnaissance receiver. We introduce sometypical LPI radar signals. Moreover, the PRBC-LFM signal is researched, and its lowinterception capacity is validated by MATLAB.Secondly, we investigated the detection and parameter estimation problem of symmetricaltriangle linear frequency modulation continuous wave(STLFMCW)signal. The existingalgorithm generally requires the hypothesis that the beginning time of interception signal is at thebeginning of modulation cycle. To break this unconscionable limit, this paper proposed a novelmethod of detection and parameter estimation for STLFMCW signal. Based on the characteristicof STLFMCW signal, this method utilizes Radon-Ambiguity Transform(RAT) frequency forevaluating modulation slope and the optimal order of Fractional Fourier Transform(FRFT). As aresult, the modulation cycle, modulation bandwidth and carrier frequency can be estimated bythe FRFT at the optimal order. This proposed method is realized by MATLAB.The simulationresults demonstrated that the proposed method overcomes the shortage of fixing beginning timeand keeps robust in low SNR of existing algorithm.Finally, to resolve the detection and parameter estimation problem of the PRBC-LFM signal,this paper gives a signal detection method by Fractional Fourier Transform. Based on the signaldetection results, a parameter estimation method based on Fractional Fourier Transform isproposed. The parameter estimation method searches peak on two-dimensional time-frequencyplane in fractional domain to get optimal rotating angular and estimate the chirp rate. Then, theFrFT with actually order is presented. The parameters, including bandwidth, initial frequency,code time width, carrier wave frequency of the signal, is estimated through the relation betweenthe peaks’ distance and the parameters of the frequency modulation signal. The coding rule of thebiphase coded signal can be identified through the estimated signal parameter. This proposedmethod is realized by MATLAB. Simulation results show that the method in this paper candetect the PRBC-LFM signal and estimate its parameters effectively at low SNR.