scholarly journals Recent Progress in the Performance Enhancement of Phase-Sensitive OTDR Vibration Sensing Systems

Sensors ◽  
2019 ◽  
Vol 19 (7) ◽  
pp. 1709 ◽  
Author(s):  
Romain Zinsou ◽  
Xin Liu ◽  
Yu Wang ◽  
Jianguo Zhang ◽  
Yuncai Wang ◽  
...  
Keyword(s):  
Recent Progress ◽  
Performance Enhancement ◽  
Signal To Noise Ratio ◽  
Time Domain Reflectometry ◽  
Vibration Sensor ◽  
Sensor Systems ◽  
Sensing Systems ◽  
Vibration Sensing ◽  
Signal Demodulation ◽  
Phase Sensitive

Recently, phase-sensitive Optical Time-Domain Reflectometry (Φ-OTDR)-based vibration sensor systems have gained the interest of many researchers and some efforts have been undertaken to push the performance limitations of Φ-OTDR sensor systems. Thus, progress in different areas of their performance evaluation factors such as improvement of the signal-to-noise ratio (SNR), spatial resolution (SR) in the sub-meter range, enlargement of the sensing range, increased frequency response bandwidth over the conventional limits, phase signal demodulation and chirped-pulse Φ-OTDR for quantitative measurement have been realized. This paper presents an overview of the recent progress in Φ-OTDR-based vibration sensing systems in the different areas mentioned above.

scholarly journals Recent Progress in the Performance Enhancement of Phase-Sensitive OTDR Vibration Sensing System

2019 ◽  
Author(s):  
Romain Zinsou ◽  
Xin Liu ◽  
Yu Wang ◽  
Jianguo Zhang ◽  
Yuncai Wang ◽  
...  
Keyword(s):  
Recent Progress ◽  
Performance Enhancement ◽  
Signal To Noise Ratio ◽  
Vibration Sensor ◽  
Sensor System ◽  
Sensing System ◽  
Vibration Sensing ◽  
Signal Demodulation ◽  
Phase Signal ◽  
Phase Sensitive

Recently, the phase-sensitive OTDR (Φ-OTDR) based vibration sensor system has gained the focus of many researchers and some efforts have been undertaken to push further the limitations imposed on the performance of the Φ-OTDR sensor system. Then, progress in the different areas of its performance evaluation factors such as: improvement of the signal-to-noise ratio (SNR), spatial resolution (SR) in the sub-meter range, enlargement of the sensing range, frequency response bandwidth over the conventional limit and phase signal demodulation for quantitative measurement have been realized. This paper presents an overview of the recent progress in the Φ-OTDR based vibration sensing system in the different areas mentioned above.

scholarly journals Performance Optimization for Phase-Sensitive OTDR Sensing System Based on Multi-Spatial Resolution Analysis

Sensors ◽  
2018 ◽  
Vol 19 (1) ◽  
pp. 83 ◽  
Author(s):  
Yuanyuan Shan ◽  
Wenbin Ji ◽  
Qing Wang ◽  
Lu Cao ◽  
Feng Wang ◽  
...  
Keyword(s):  
Spatial Resolution ◽  
Performance Optimization ◽  
Signal To Noise Ratio ◽  
Time Domain Reflectometry ◽  
Sensing System ◽  
Optical Time Domain Reflectometry ◽  
Resolution Analysis ◽  
Phase Sensitive ◽  
Optical Time ◽  
Qualitative Relationship

This paper proposes and demonstrates a phase-sensitive optical time domain reflectometry (Φ-OTDR) sensing system with multi-spatial resolution (MSR) analysis property. With both theoretical analysis and an experiment, the qualitative relationship between spatial resolution (SR), signal-to-noise ratio (SNR) and the length of the vibration region has been revealed, which indicates that choosing a suitable SR to analyze the vibration event can effectively enhance the SNR of a sensing system. The proposed MSR sensing scheme offers a promising solution for the performance optimization of Φ-OTDR sensing systems, which can restore vibration events of different disturbance range with optimum SNR in merely a single measurement while maintaining the same detectable frequency range.

scholarly journals Performance Enhancement Methods for the Distributed Acoustic Sensors Based on Frequency Division Multiplexing

Electronics ◽  
2019 ◽  
Vol 8 (6) ◽  
pp. 617 ◽  
Author(s):  
Yanzhu Hu ◽  
Zhen Meng ◽  
Mohammadmasoud Zabihi ◽  
Yuanyuan Shan ◽  
Siyi Fu ◽  
...  
Keyword(s):  
Performance Enhancement ◽  
Signal To Noise Ratio ◽  
Dead Zone ◽  
High Sensitivity ◽  
Time Domain Reflectometry ◽  
System Structure ◽  
Frequency Division Multiplexing ◽  
Frequency Division ◽  
Rayleigh Backscattering ◽  
Sensing System

The last years have witnessed the wide application of Distributed Acoustic Sensor (DAS) systems in several fields, such as submarine cable monitoring, seismic wave detection, structural health monitoring, etc. Due to their distributed measurement ability and high sensitivity, DAS systems can be employed as a promising tool for the phase sensitive optical time domain reflectometry (Φ-OTDR). However, it is also well-known that the traditional Φ-OTDR system suffers from Rayleigh backscattering (RBS) fading effects, which induce dead zones in the measurement results. Worse still, in practice it is difficult to achieve the optimum matching between spatial resolution (SR) and signal to noise ratio (SNR). Further, the overall frequency response range (FRR) of the traditional Φ-OTDR is commonly limited by the length of the fiber in order to prevent RBS signals from overlapping with each other. Additionally, it is usually difficult to reconstruct high frequency vibration signals accurately for long range monitoring. Aiming at solving these problems, we introduce frequency division multiplexing (FDM) that makes it easier to improve the system performance with less system structure changes. We propose several novel Φ-OTDR schemes based on Frequency Division Multiplexing (FDM) technology to solve the above problems. Experimental results showed that the distortion induced by fading effects could be suppressed to 1.26%; when the SR of Φ-OTDR is consistent with the length of the vibration region, the SNR of the sensing system is improved by 3 dB compared to the average SNR with different SRs; vibration frequencies up to 440 kHz have been detected along 330 m artificial microstructures. Thus, the proposed sensing system offers a promising solution for the performance enhancement of DAS systems that could achieve high SNR, broadband FRR and dead zone-free measurements at the same time.

scholarly journals Performance Enhancement of the Location and Recognition of a Φ-OTDR System Using CEEMDAN-KL and AMNBP

2020 ◽  
Vol 10 (9) ◽  
pp. 3047
Author(s):  
Yanzhu Hu ◽  
Zhen Meng ◽  
Xinbo Ai ◽  
Yu Hu ◽  
Yixin Zhang ◽  
...  
Keyword(s):  
Performance Enhancement ◽  
Signal To Noise Ratio ◽  
Dead Zone ◽  
Recognition Rate ◽  
High Sensitivity ◽  
Ensemble Empirical Mode Decomposition ◽  
Time Domain Reflectometry ◽  
Long Distance ◽  
Practical Applications ◽  
Leibler Divergence

It is commonly known that for characteristics, such as long-distance, high-sensitivity, and full-scale monitoring, phase-sensitive optical time-domain reflectometry (Φ-OTDR) has developed rapidly in many fields, especially with the arrival of 5G. Nevertheless, there are still some problems obstructing the application for practical environments. First, the fading effect leads to some results falling into the dead zone, which cannot be demodulated effectively. Second, because of the high sensitivity, the Φ-OTDR system is easy to be interfered with by strong noise in practical environments. Third, the large volume of data caused by the fast responses require a lot of calculations. All the above problems hinder the performance of Φ-OTDR in practical applications. This paper proposes an integration method based on a complete ensemble empirical mode decomposition with adaptive noise and Kullback–Leibler divergence (CEEMDAN-KL) and an adaptive moving neighbor binary pattern (AMNBP) to enhance the performance of Φ-OTDR. CEEMDAN-KL improved the signal characteristics in low signal-to-noise ratio (SNR) conditions. AMNBP optimized the location and recognition via a high calculation efficiency. Experimental results show that the average recognition rate of four kinds of events reached 94.03% and the calculation efficiency increased by 20.0%, which show the excellent performance of Φ-OTDR regarding location and recognition in practical environments.

scholarly journals Fiber Optic Based Distributed Mechanical Vibration Sensing

Sensors ◽  
2021 ◽  
Vol 21 (14) ◽  
pp. 4779
Author(s):  
Vít Novotný ◽  
Petr Sysel ◽  
Aleš Prokeš ◽  
Pavel Hanák ◽  
Karel Slavíček ◽  
...  
Keyword(s):  
Mechanical Vibration ◽  
Single Mode ◽  
Time Domain Reflectometry ◽  
Sensing System ◽  
Optical Time Domain Reflectometry ◽  
Measurement Results ◽  
Vibration Sensing ◽  
Phase Sensitive ◽  
Optical Time ◽  
Initial Measurement

The distributed long-range sensing system, using the standard telecommunication single-mode optical fiber for the distributed sensing of mechanical vibrations, is described. Various events generating vibrations, such as a walking or running person, moving car, train, and many other vibration sources, can be detected, localized, and classified. The sensor is based on phase-sensitive optical time-domain reflectometry (ϕ-OTDR). Related sensing system components were designed and constructed, and the system was tested both in the laboratory and in the real deployment, with an 88 km telecom optical link, and the results are presented in this paper. A two-fiber sensor unit, with a double-sensing range was also designed, and its scheme is described. The unit was constructed and the initial measurement results are presented.

scholarly journals Time-expanded phase-sensitive optical time-domain reflectometry

2021 ◽  
Vol 10 (1) ◽  
Author(s):  
Miguel Soriano-Amat ◽  
Hugo F. Martins ◽  
Vicente Durán ◽  
Luis Costa ◽  
Sonia Martin-Lopez ◽  
...  
Keyword(s):  
Time Domain ◽  
Signal To Noise Ratio ◽  
Random Phase ◽  
Environmental Variable ◽  
Time Domain Reflectometry ◽  
Trade Offs ◽  
Optical Time Domain Reflectometry ◽  
Phase Sensitive ◽  
Spatio Temporal ◽  
Optical Time

AbstractPhase-sensitive optical time-domain reflectometry (ΦOTDR) is a well-established technique that provides spatio-temporal measurements of an environmental variable in real time. This unique capability is being leveraged in an ever-increasing number of applications, from energy transportation or civil security to seismology. To date, a wide number of different approaches have been implemented, providing a plethora of options in terms of performance (resolution, acquisition bandwidth, sensitivity or range). However, to achieve high spatial resolutions, detection bandwidths in the GHz range are typically required, substantially increasing the system cost and complexity. Here, we present a novel ΦOTDR approach that allows a customized time expansion of the received optical traces. Hence, the presented technique reaches cm-scale spatial resolutions over 1 km while requiring a remarkably low detection bandwidth in the MHz regime. This approach relies on the use of dual-comb spectrometry to interrogate the fibre and sample the backscattered light. Random phase-spectral coding is applied to the employed combs to maximize the signal-to-noise ratio of the sensing scheme. A comparison of the proposed method with alternative approaches aimed at similar operation features is provided, along with a thorough analysis of the new trade-offs. Our results demonstrate a radically novel high-resolution ΦOTDR scheme, which could promote new applications in metrology, borehole monitoring or aerospace.

scholarly journals Localization and Discrimination of the Perturbation Signals in Fiber Distributed Acoustic Sensing Systems Using Spatial Average Kurtosis

Sensors ◽  
2018 ◽  
Vol 18 (9) ◽  
pp. 2839 ◽  
Author(s):  
Fei Jiang ◽  
Honglang Li ◽  
Zhenhai Zhang ◽  
Yixin Zhang ◽  
Xuping Zhang
Keyword(s):  
False Alarm ◽  
Signal To Noise Ratio ◽  
Moving Average ◽  
Spatial Dimension ◽  
Time Domain Reflectometry ◽  
Spatial Average ◽  
Acoustic Sensing ◽  
Sensing Systems ◽  
Distributed Acoustic Sensing ◽  
Optical Time

Location error and false alarm are noticeable problems in fiber distributed acoustic sensing systems based on phase-sensitive optical time-domain reflectometry (Φ-OTDR). A novel method based on signal kurtosis is proposed to locate and discriminate perturbations in Φ-OTDR systems. The spatial kurtosis (SK) along the fiber is firstly obtained by calculating the kurtosis of acoustic signals at each position of the fiber in a short time period. After the moving average on the spatial dimension, the spatial average kurtosis (SAK) is then obtained, whose peak can accurately locate the center of the vibration segment. By comparing the SAK value with a certain threshold, we may to some degree discriminate the instantaneous destructive perturbations from the system noise and certain ambient environmental interferences. The experimental results show that, comparing with the average of the previous localization methods, the SAK method improves the pencil-break and digging locating signal-to-noise ratio (SNR) by 16.6 dB and 17.3 dB, respectively; and decreases the location standard deviation by 7.3 m and 9.1 m, respectively. For the instantaneous destructive perturbation (pencil-break and digging) detection, the false alarm rate can be as low as 1.02%, while the detection probability is maintained as high as 95.57%. In addition, the time consumption of the SAK method is adequate for a real-time Φ-OTDR system.

scholarly journals Vibration Sensor Based on Hollow Biconical Fiber

Sensors ◽  
2021 ◽  
Vol 21 (4) ◽  
pp. 1023
Author(s):  
Yingfang Zhang ◽  
Ben Xu ◽  
Dongning Wang ◽  
Yun Guo ◽  
Min Chen ◽  
...  
Keyword(s):  
Transmission Loss ◽  
Signal To Noise Ratio ◽  
Sound Intensity ◽  
Single Mode ◽  
Acoustic Vibration ◽  
Single Mode Fiber ◽  
Vibration Sensor ◽  
Acoustic Frequency ◽  
Compact Size ◽  
Vibration Sensing

A hollow biconical fiber is proposed and experimentally demonstrated for vibration sensing. It is fabricated by creating an air micro-cavity in single-mode fiber, followed by tapering it. Experimental results show that the device is highly sensitive to bending with a sensitivity of 21.30 dB/m−1. When it is exposed to vibration, its transmission loss is modulated periodically, then based on the measured transmission, the vibration frequency can be demodulated accurately. The acoustic vibration testing results show that the proposed device can detect and demodulate the exciting acoustic frequency accurately and distinguish its sound intensity, and the maximum signal to noise ratio (SNR) achieves up to 59 dB. Moreover, cantilever beam testing proves its performance reliable. Additionally, the sensing head has the advantages of a lightweight, compact size (with a total length of less than 250 μm), and insensitivity of temperature. All these features indicate the proposed sensor has a promising potential in the engineering field.

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