Two-Dimensional Timestamp-Based Sliding Window Cross Correlation Localization Algorithm for Distributed Optical Fiber Vibration Sensing Interferometer

Distributed optical fiber sensing interferometers have emerged as promising tools for various sensing applications. In this article, we present a novel 2-D timestamp-based sliding window cross correlation algorithm for a distributed optical fiber sensing interferometer based on shifting difference signal reconstruction. The proposed scheme overcomes the limitation of traditional cross correlation in the multiple vibration situations, enabling to distinguish multiple disturbance signals. Theoretical analysis on quantization noise and performance with different window lengths is presented. The experimental demonstration over a 60 km fiber is conducted to localize vibration signals. By incorporation fitting, the proposed algorithm achieves the spatial resolution improvement from ±20 to ±2 m with an average localization accuracy of ±4.34 m at the sensing length of 60 km (±0.014%). The proposed algorithm significantly improves the accuracy of localization and enables real-time tracking of cross-correlation patterns in both spatial and time domains, thereby improving localization accuracy and versatility of signal monitoring.