A Pre-estimation Algorithm for LFM Signal Based on Simplified Fractional Fourier Transform

摘要

In this paper, a pre-estimation algorithm (PEA) is given to estimate approximately the chirp ratio of multi-component linear frequency modulated signal (LFM, chirp). And a simplified fractional Fourier transform (SFFT) is introduced to estimate the all parameter of multi-LFM signal. Then, a new fast method combining STFT with PEA and "clean" technique is presented for multi-LFM signal detection and parameter estimation. As SFFT is a linear transform, the correlated cross-item problem for dealing with multi-components can be avoided effectively. SFFT has a more simplified version compared with fractional Fourier transform (FRET), which makes it more appropriate to process LFM signal. With the pre-estimation algorithm, the detection time can be reduced several orders of magnitude than direct-detecting algorithm by SFFT. And the effectiveness of the proposed approach is demonstrated via computer simulations.