基于积分二次相位函数和分数阶Fourier变换的多分量LFM信号参数估计

针对高斯白噪声中多分量线性调频信号参数估计问题，提出了一种基于积分二次相位函数（IQPF）和分数阶Fourier变换的新方法。分析了IQPF估计线性调频信号调频率的原理，指出IQPF有压制弱信号的缺点。为解决强度相差较大的多分量线性调频信号中弱分量信号的参数估计问题，提出利用分数阶Fourier变换域的信号分离技术，逐次估计强信号分量的参数并将其消去，来提高多分量信号参数估计的可靠性。最后通过计算机仿真，验证了该方法的有效性。这种方法与Radon-Winger变换法、Radon-Ambiguity变换法和单纯的分数阶Fourier变换法相比，极大的简化了计算。因此，该方法非常适合于多分量LFM信号的快速参数估计。 

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.