Study On The Method Of Amplitude Time-varying Chirp Signal Parameters And Time Delay Joint Estimation

Among the non-stationary signals, the Chirp signal is widely used in the fields ofradar, communication, biomedicine, sonar, seismic survey etc. Due to the environmentfactors, the amplitude of the Chirp signal cannot be kept constant. Therefore, it haspractical meanings to study the variable amplitude Chirp signal.This thesis takes the Chirp signal of which the amplitude is varied with the timelinearization and study the estimation method of the Chirp signals in terms of theinitial frequency, the frequency modulation slop, the amplitude coefficient and thetime delay estimations among the echo signals. The main work of this thesis issummarized as follows:1. It provides theory of time delay estimation form fractional Fourier transform toconstant amplitude Chirp signal and fractional Fourier transform method applies tothe Chirp signal the time can linearize the amplitude in time delay estimation.2. Use Radon-Wigner transform to study parameters estimation of the Chirp signalthat the time can linearize the amplitude and contrast to constant amplitude Chirpsignal and to analysis errors of Fourier transform method to estimate amplitudecoefficient and analysis the errors of parameters estimation results, and it gives thecontrast of parameter estimation performance between Radon-Wigner transform andRadon-STFT transform. It illustrate the article has strongly flexibility.3. Use fractional Fourier transform to study time delay estimation of Chirp signal thatthe time can linearize the amplitude and contrast to constant amplitude Chirp signal.Analysis errors of time delay estimation’s emulation-al results, and it gives thecontrast of time delay estimation performance between fractional Fourier transformand short-time Fourier transform spectrogram correlated with frequency domain. Itillustrate the article has strongly flexibility.Through this research work, it can ben conclusion: it is feasible to use fractionalFourier transform to study time delay estimation of Chirp signal that the time canlinearize the amplitude. Under the condition of high SNR,the estimation accuracy is basically satisfy the practical engineering requires, and in the condition of unknownamplitude, it still can estimate parameters and the time delay values of signal well,andprove this way has strong flexibility and the good practical significance of theprogramme.