Time-frequency Analysis And Its Application In Pulse Compression Signal Parameter Estimation

Studying the characteristics of low probability of interception(LPI) radar pulsecompression signal will be helpful in identifying and sorting these signals effectively inmodern ESM System and ELINT System.Because LPI signals are non-stationary,whichmeans their instantaneous frequency changes over time, so traditional time-domain andfrequency-domain analysis methods are not useful in identifying them.This article mainlystudies the application of time-frequency analysis methods in identifying In-pulsemodulation characteristics of radar pulse compression signal.Model recognition method andin-pulse modulation characteristic parameter estimation method of pulse compressionsignals will be concretely presented here.A method is discussed here to extract the instantaneous frequency of LFM/steppedfrequency signal in wavelet domain.The usage is made of the relationship between themaximum of wavelet modulus and the wavelet function;Wigner-Ville distribution andambiguity function theory are applied in the detection of LFM signal,advantages anddisadvantages of both methods are compared through computer simulation under differentsignal-to-noise ratio;Model identification method for phase-coded pulse compressionsignals is presented based on short-time Fourier transform and Wavelet transform methods,computer simulation results indicate that the method can effectively identify the carrierfrequency and pulse width of phase-coded pulse compression signal.Finally an inquiry into application of time-frequency analysis in in-pulse modulationcharacteristic parameter estimation of LFM is presented.Proposing improved Wavelet-ridgemethod of extracting instantaneous frequency of LFM;Deducing LFM parameter estimationmethod based on Wigner-Hough transformation.Computer simulation results show thatthese methods can effectively estimate modulation feature parameters of LFM signal.