The fully polarized Radar Cross Section(RCS) sequences of two simulated ballistic targets are obtained from microwave anechoic static measurement inversion under typical combat conditions. In view of the nonsmoothness and proposed periodicity characteristics of this time series, it is not effective to estimate precession period directly by spectral analysis. Therefore, wavelet method is employed to reduce noise and enhance the details of the precession passband in the pre-processing process. The full polarization channel fusion process is carried out by Principal Component Analysis(PCA) and polarization invariant method respectively. The experiment results show that the extraction method using polarization information is significantly better than the single polarization channel extraction method, and the error is less than 0.002 Hz in noiseless observation environment.