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Parameter estimation of multi component LFM signals based on nonlinear mode decomposition and FrFT

Noise and chaos exist commonly in the natural phenomena, which affects the performance of signal detection. A new approach based on nonlinear mode decomposition (NMD) and Fractional Fourier transform (FrFT) to conduct the parameter estimation of the multi-component linear frequency modulation (LFM) signals is proposed in this paper. This method applies NMD to the multi-component LFM signals to obtain a series of meaningful single component LFM signals with suppressing noise and interference. Then correlation coefficient is calculated to select the appropriate decomposed components and FrFT is used to complete parameter estimation. Numerical simulation and analysis have shown that the proposed method has the advantage of extracting LFM signals with different time-varying amplitudes under the condition of white noise, chaos and ocean ambient noise. The novel approach based on NMD and FrFT is superior to other methods based on mode decomposition and FrFT in quantitative comparisons.