Parameter Estimation of LFM Signal by Direct and Spline Interpolation Based on FrFT

An important cause of performance loss in parameter estimation of linear frequency modulation (LFM) signal based on Fractional Fourier Transform (FrFT) is the “picket fence effect” because of the discretization of FrFT. In this work, a direct and spline interpolation method, along with a coarse search, is investigated and is used for parameter estimation of LFM signal based on FrFT. In FrFT domain, the parameter estimation of a LFM signal is equivalent to search the peak of the FrFT coefficients. The direct and spline interpolation method, instead of a conventional fine search algorithm, can not only improve the estimation accuracy of the peak coordinate, which leads to a better performance of the LFM parameter estimation, but also save computation load. Performance of the proposed method is analyzed by digital simulations at different signal to noise ratio (SNR) levels, and good performance is achieved.