Bispectrum and subsection dechirp for the LFM signal parameter estimation

To estimate the parameters of linear frequency modulation (LFM) signals with low signal-to-noise ratio (SNR), an improved method is proposed. Firstly, the position of LFM signal spectrum is estimated using bispectrum slice, then the signal is filtered out by means of a band-pass filter, finally subsection dechirp is made for parameter estimation. By combining successive elimination technique with above method, weak LFM signals can be detected among some strong LFM signals and their parameters are estimated. Compared with conventional method, this method can suppress the effects of noise and cross-reference based on the characters of higher-order cumulants. Simulation results show its effectiveness.