基于φ-OTDR 的分布式光纤声波传感系统性能改进研究

Research on Performance Improvement of Distributed Fiber Acoustic Sensing System Based on φ-OTDR

摘要:

为了满足复杂的工程现场环境对相敏光时域反射仪(φ-OTDR)的各项性能指标的需求,提出基于自适应卡尔曼滤波(AKF)和频分复用(FDM)的高性能φ-OTDR,利用FDM提升系统的频响带宽,引入AKF对线性响应于外界振动的相位状态的噪声统计特性进行实时估计和修正,抑制了衰落和串扰导致的相位失真。实验结果表明,改进后φ-OTDR系统的传感线性度被有效提升,系统本底噪声降低到-83.7dB²/Hz,应变分辨率达到了0.28pε/Hz1/2。

Abstract:

In order to meet the requirements of performance indexes of φ-OTDR in complex engineering field environment, a high-performance φ-OTDR based on adaptive Kalman filter (AKF) and frequency division multiplexing (FDM) is proposed. On the basis of improving frequency response bandwidth of FDM, AKF is used to estimate and correct the statistical characteristics of phase noise linearly responding to external vibration in real time, effectively suppressing the phase distortion caused by fading and crosstalk noise. The experimental results show that sensor linearity of the system is improved, the background noise of the system is reduced to -83.7dB²/Hz, and the strain resolution is reduced to 0.28pε/Hz1/2.