Enhancing Detection Performance of the Phase-Sensitive OTDR Based Distributed Vibration Sensor Using Weighted Singular Value Decomposition

Khurram Naeem,Bok Hyeon Kim,Il-Bum Kwon,Dong-Jin Yoon

doi:10.3390/app11041928

Abstract

We propose a weighted singular value decomposition (WSVD) to reduce the random noise in the Rayleigh backscattering signal of the phase-sensitive optical time domain reflectometry (Φ-OTDR) to enhance the detection performance of the distributed vibration sensing. A 2D image is formed by assembling the raw Rayleigh backscattering traces into a matrix form, and slowly varying fluctuation and random noise can be removed using the WSVD. Consequently, the location information and the frequency of vibration induced by the external vibration event can be extracted. A vibration event with 9 m spatial resolution is detected along a 2.4 km single mode fiber. The signal-to-noise ratio (SNR) of location information for the 102 Hz physical vibration and the 525 Hz acoustic vibration was found to be 10.7 and 12.2 dB, respectively. The SNR of the vibration events demonstrate an increase of 6–7 dB compared to the conventional method, showing the excellent denoising capability of this new approach.

Highlights

Distributed fiber optic vibration sensors have gained much attention over the years due to their unique advantages: they are immune to electromagnetic interference, have high detection sensitivity and fast detection response, and can be deployed in harsh conditions at low cost [1,2]
For distributed vibration sensing based on optical fiber, one particular technique is the use of the phase-sensitive optical time-domain reflectometer (Φ-OTDR) [3,4,5,6]
In the Φ-OTDR, highly coherent light pulses are launched into a sensing fiber, and the signal traces, which result from the coherent interference of Rayleigh backscattering light originating from multiple scattering centers within the pulse duration, are acquired all along the length of the sensing fiber [12]

Summary

Introduction

Distributed fiber optic vibration sensors have gained much attention over the years due to their unique advantages: they are immune to electromagnetic interference, have high detection sensitivity and fast detection response, and can be deployed in harsh conditions at low cost [1,2]. The second approach, due to Φ-OTDR being a distributed sensor that produces raw backscattering data in large amounts, relies on the signal processing of the raw data using efficient mathematical algorithms to improve the SNR of the vibration event.

Results

Conclusion