The parameters estimation of underwater transient signal based on FRFT

The ignition signal of the underwater vehicle is one of the important features. According to the shortness of the ignition signal in time domain, the signal could be similarly considered as a Linear Frequency Modulated (LFM) signal. The feature extraction comes down to the estimation of the initial frequency and the frequency modulation rate of the LFM signal. The initial frequency and the frequency modulation rate of the LFM signal could be estimated based on the Fractional Fourier Transform(FRFT) algorithm, and the normalization is solved by discrete scaling transform method. The composition of the multi Chirp signal could be estimated one by one through the FRFT algorithm. The simulations of the single Chirp signal and multi Chirp signal are carried out. The result of the simulation proved that the parameters estimation based on the FRFT algorithm is effective. Compared to the traditional slope rate algorithm the FRFT is more objective and more accurate.