A Fast Signal Parameter Estimation Algorithm for Linear Frequency Modulation Signal under Low Signal-to-Noise Ratio Based on Fractional Fourier Transform

An algorithm based on high-efficiency FRactional Fourier Transform (FRFT) and fourth-order origin moments in the fractional-domain spectrum is proposed to estimate quickly the chirp signal at low signal-to-noise ratio. Firstly, the initial interval of the rotation order is determined by the sign of the FM slope. Then, the rotation order is estimated roughly by the efficient FRFT algorithm. Finally, the search interval and step size are determined according to the fourth-order origin moments of the spectrum in the fractional-domain. The simulation results show that the Linear Frequency Modulation (LFM) signal can be detected under low signal-to-noise ratio and the parameters of the signal can be estimated accurately using this algorithm, and the signal can be detected with a small amount of calculation.