Fiber Optic Cable End Detection with Adaptive DAS Thresholding
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing Distributed Acoustic Sensing (DAS) systems lack a robust method to detect fiber optic cable ends and unexpected breaks, and existing methods do not effectively suppress peaks or perform adaptive thresholding to make line cuts/end explicit.
Innovation Solution
A method involving generating laser pulses, processing reflected signals through log(log(x)) transformation, low-pass filtering, and applying STA/LTA algorithms with adaptive thresholding to identify and predict fiber optic cable ends and breaks, using a control unit to analyze amplitude data and detect change points.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If traditional OTDR devices are used to detect fiber optic cable ends, then detection capability is provided, but the OTDR device and DAS sensors cannot be operated at the same time
Solution Approach 1:
The DAS system is enhanced to perform multiple functions: it continues to monitor acoustic vibrations for intrusion detection and other applications while simultaneously detecting fiber optic cable ends and breaks using the same fiber infrastructure. This eliminates the need for separate OTDR devices and enables concurrent operation of DAS sensors and cable end detection.
2Reliability
If existing DAS methods are used to detect cable ends, then detection is possible, but peaks are not suppressed and change points are not made explicit
Solution Approach 1:
The method extracts and removes peak components from the DAS signal using adaptive thresholding and peak suppression techniques. By identifying and eliminating these peaks, the signal becomes clearer and change points associated with cable ends or breaks become explicit and easier to detect with higher precision.
Solution Approach 2:
The method applies transformations to the signal parameters including taking the logarithm of the signal, applying low-pass filtering, and using adaptive thresholding with dynamically adjusted thresholds. These parameter changes enhance the visibility of change points and make cable end detection more precise.
3Measurement precision
If statistical extraction methods are used to determine cable termination points, then detection is achieved, but system downtime increases due to lack of automatic fault detection
Solution Approach 1:
The system continuously monitors the DAS signal and automatically detects cable breaks and faults in real-time using peak suppression and adaptive thresholding. This preliminary detection capability allows the system to identify issues before they fully manifest, enabling proactive maintenance and reducing system downtime by eliminating the need for manual inspection and statistical analysis.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
Enables robust detection of fiber optic cable ends and breaks by highlighting change points and providing accurate predictions through adaptive thresholding, reducing system downtime and improving performance.
Implementation Method 1
generating a laser pulse by a laser light source
Implementation Method 2
measurements related to electronic noise are statistically extracted and the fiber cable termination point is determined... DAS systems work on the principle of periodically measuring the phase difference scattered by Rayleigh reflections of the highfrequency laser beam sent over the fiber optic cable
Implementation Method 3
detecting laser pulses reflected from a fiber optic cable by an optical sensor
Data Source
Figure 1
Figure 2~4
Figure 5~7
AI summary
The invention relates to a line cut/end detection method, which enables the detection of the end point of a fiber optic cable used in distributed acoustic systems and unexpected/unwanted breaks or interruptions in said fiber optic cable. The line cut/end detection method which is the subject of the invention, comprising the process steps of; sending a laser pulse to a fiber optic cable and collecting raw data including amplitude data for each channel, creating a data stack for each channel by repeating the raw data collection process a predetermined number of times, calculating the standard deviation values (σc) of amplitude values in data sets, applying log(log(x)) transformation to the obtained signal and applying a low-pass filter operation, respectively, applying an STA/LTA algorithm to the filtered signal, calculating an adaptive threshold value (τ) depending on the mean (µσ), standard deviation (σσ) of the obtained STA/LTA values (σ̂c) and a predetermined hyperparameter (β), obtaining the peaks exceeding the adaptive threshold value (τ) and the channels related to these peaks, grouping the consecutive peaks obtained and determining the channel with the smallest channel number in the group with the largest channel number as the line cut/end candidate among said groups.