Abstract:In order to solve the problem of poor demodulation accuracy of vibration sensing systems affected by noise during practical applications，the interference signal coefficients are predicted and corrected using the Unscented Kalman Filter，and then the accurate vibration signals are obtained by the demodulation through the differential cross-multiplication method. Simulation results show that the method has better accuracy and noise immunity compared with the commonly used ellipse fitting method. The proposed method is applied to a fiber optic vibration sensing system based on a distributed feedback fiber laser as experiments，and the results show that when the SNR is 6 dB，the demodulation accuracy is four times that of the least squares method.