A modified CPF algorithm for estimating the parameters of multicomponent third-order polynomial phase signals

A modified CPF algorithm for estimating the parameters of multi-component third-order polynomial phase signals is proposed in this paper. The proposed algorithm requires only one-dimensional maximizations, and fast Fourier transformation is used to achieve the initial parameters values. In contrast with the algorithm for estimating mono-component PPSs by using the cubic phase function, it must solve the corresponding relation of the instantaneous frequencies at the two different time positions. Therefore, In order to obtain the correct estimation for the two highest-order parameters of each component, firstly, all possible parameters for two highest-order must be obtained. Secondly, use these parameters to dechirp the multi-component third-order PPS, and the dechirped signal is implemented with FFT. Finally, find the maximum amplitude during all converted signals by using FFT. Thus the estimated parameters corresponding to the maximum amplitude are correct, and the others are incorrect. The refined algorithm can avoid the incorrect parameter estimations of multi-component third-order PPS, and a theoretical analysis and simulations are provided to support the claim.