An Improved Parameter Estimation Algorithm of LFM Signal Based on the Fractional Fourier Transform

Abstract

Linear Frequency Modulation (LFM) signal is a common signal in the radar system, how to do parameter estimation of LFM signal quickly and accurately is always the research hot spot. The fractional Fourier Transform (FRFT) as an emerging time-frequency analysis method, because of its transform nuclear is chirp matrix decomposition, so especially suitable for LFM signal processing. But it needs to do global search because the modulation frequency is unknown, which lead to a large amount of calculation. This paper proposed an improved parameter estimation algorithm of LFM signal. We made a rough estimation of modulation frequency by the fast Radon Wigner Transform (RWT) firstly, and then the amount of calculation can be reduced because it only needs to do local search for find the optimal fractional order. In addition, we made a comparison among the new method and other two LFM signal parameter estimation algorithms, and got simulation results under different SNRs. Simulation results show that, parameter estimation accuracy is improved by new algorithm compared to other two algorithms under the same calculation.