Parameter Estimation of Multi-component LFM Signals Using Integrated Quadratic Phase Function and Fractional Fourier Transform

To estimate the parameters of multi-component linear frequency modulation (LFM) signals in the presence of white Gaussian noise, a new method based on integrated quadratic phase function (IQPF) and fractional Fourier transform is presented. The theory of IQPF for estimating the chirp rate is analyzed and the shortcoming of suppressing the weak LFM signal is pointed out. In order to estimate the parameters of the weak LFM signals in cases involving the strong LFM signals, a novel scheme is put forward. It combines IQPF with the fractional Fourier transform to estimate the parameters of strong LFM signals and then eliminate them one by one. Computer simulations have verified the effectiveness of the method. Compared with Radon-Winger transform (RWT), Radon-Ambiguity transform (RAT) and pure fractional Fourier transform, the proposed method is more computationally efficient. Hence, the method can serve as a good candidate for quick parameter estimation of multi-component LFM signals.