Abstract
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.
Highlights
Fiber distributed acoustic sensing systems based on phase-sensitive optical time domain reflectometry (Φ-OTDR) have been widely used in many fields such as oil and gas pipeline monitoring, structure health monitoring, and perimeter security [1,2,3,4] due to their high sensitivity, large dynamic range, fully distributed manner, and simple configuration
A total of 200 tests, including 100 pencil-break tests
A total of 200 tests, including 100 pencil-break tests (50 of which were under 100 ns pulse width width and 50 of which were under 500 ns pulse width) and 100 digging tests (50 of which were and 50 of which were under 500 ns pulse width) and 100 digging tests (50 of which were under 100 ns pulse width and 50 of which were under 500 ns pulse width) were carried out to evaluate the localization performance of proposed method
Summary
Fiber distributed acoustic sensing systems based on phase-sensitive optical time domain reflectometry (Φ-OTDR) have been widely used in many fields such as oil and gas pipeline monitoring, structure health monitoring, and perimeter security [1,2,3,4] due to their high sensitivity, large dynamic range, fully distributed manner, and simple configuration. The principal of Φ-OTDR is based on the interference of Rayleigh scattering lights returned from the fiber. The phase of the Rayleigh scattering lights can be affected by external vibration events, which will result in the amplitude variation of the Rayleigh scattering traces. In Φ-OTDR systems, locating the vibration events is an essential problem. The vibration location can be obtained by subtracting a Rayleigh trace from an earlier stored trace [1]. This method may cause false locations due to the amplitude fluctuation in Rayleigh traces and the system noise of Φ-OTDR
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
