Improved estimation algorithm of multi-component LFM signal parameters and its fast implementation

An algorithm for estimating the multi-component linear frequency modulation (LFM) signal parameters based on the improved cubic phase function is proposed. A two-order nonlinear transform is just needed to form maximization in parameter field for estimating the parameters of the LFM signal. For multi-component LFM signals, the relations between the self-terms or cross-terms and the time are discussed. It indicates that there is different dependence of self-terms and cross-terms on time. To conquer the influence of the cross-term, a weighted mean method is proposed. Then the FFT algorithm of the cubic phase function is derived, and is further improved through rounding the last sample point so as to use in practical discrete sampling systems. Simulation results show that the method has obvious effects to estimate the parameters of multi-component LFM signals in low SNR, and the relevant FFT algorithm holds good performance while saving operations mostly compared with the previous algorithm.