An Improved Algorithm of Parameters Estimation for Frequency-Hopping Signal

In view of the problem of S-transform that the width of the window shortens quickly with the increase of frequency, and the performance of parameter estimation of FH (Frequency-Hopping) decline, an improved algorithm based on asymmetric window is proposed. The algorithm firstly studies the window function of S-transform, and selects hyperbola of window function. This window function suits for estimation of FH parameter. Because rising and falling edge of this window function has large degree of freedom, on the anther hand the asymmetry of the window function varies with frequency. Considering the distortion of the ridge line at high frequency component, and combining with the statistical property of white Gaussian noise in S spectrum, an indirect band-pass filtering method in time-frequency plane is proposed to smooth the ridge line and decline the influence of noise. Theoretical analysis and simulation results verify the effectiveness and feasibility of the proposed algorithm.