Accurate Regional Localization Method for Φ-OTDR Based on Overlapping Phases Cross-Correlation

Aiming to enhance the vibration localization capability of phase-sensitive optical time domain reflectometry (
$\Phi $
-OTDR), a regional localization method based on overlapping phases cross-correlation is proposed to improve the positioning accuracy and signal-to-noise ratio (SNR). Due to the linear relationship between the phase signal and the external disturbance, the cross-correlation of the two phase matrices are calculated and the maximum value appears in the full link can represent the location of the vibration. Meanwhile, autocorrelation is introduced to improve the localization effect. The regional localization accuracy achieved by the proposed method is above 98%, and the average SNR is 59.37 dB in actual vibration experiment. The improved localization method decreases the noise peak rate by more than 20% in single-point vibration experiment compared with that before the improvement.