The improved parameter estimation method based on fractional fourier transform

For the parameter estimation of linear frequency modulated (LFM) signal, this paper presents an improved arithmetic which is based on fractional Fourier transform (FRFT). Firstly, this paper analyzes the shortcomings of previous methods. Then, according to the characteristics of the LFM signal, a method based on fast Fourier transform (FFT) is used to estimate the coarse chirp rate. Secondly, by analyzing the redundancy of FRFT decomposition, reduced fractional Fourier transform (RFRFT) algorithm is proposed. Then, it develops relationship of signal parameter before and after normalization. Thirdly, it presents a more effective method based on FRFT to implement the parameter estimation of LFM signal. This improved arithmetic enhances the speed of calculation greatly. Finally, simulation results validate the method is able to suppress the noise and cross-terms in lower Signal-to-Noise Ratio (SNR).Comparing with the traditional FRFT, this method has a good performance to match multi-component LFM signals.