Traditional parameters estimation methods for the Multi-component Linear Frequency Modulation (MLFM) signal based on Fractional Fourier Transform (FRFT) could not achieve the satisfactory precision and the lesser computation cost. In this paper, we propose a new method combining the Short Time Fourier Transform (STFT) and Zoom-FRFT, to estimate the MLFM signal parameters. Firstly, the coarse estimation can be achieved from the straight line detection of short time Fourier spectrum. Then, we could calculate the analysis range of transform order and Fractional domain spectrum by the FRFT domain spectrum distribution characteristics of interference signal. Finally, we can estimate the optimal order and precise peak position by the optimum seeking method in the Zoom-FRFT domain. The simulation results show that, this method can improve both the parameters estimation precision and the computation cost significantly, and can flexibly choose the window width and the zoom times.
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