Distributed Acoustic Sensing Signal Processing for Event Positioning
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Solution Overview
Problem
Distributed acoustic sensing systems face challenges in specifying the detailed position of detected events due to the trade-off between signal intensity and signal-to-noise ratio, which affects the spatial resolution of event detection.
Innovation Solution
A processing apparatus that acquires signal groups from both long and short gauge length sections in an optical fiber, selects a long gauge length section based on signal features, and determines the short gauge length section where an event occurred using corresponding signal features.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a long gauge length section is used in DAS, then the signal intensity is high and SN ratio is improved, but the spatial resolution for specifying event position deteriorates
Solution Approach 1:
The invention divides the optical fiber into multiple gauge length sections with different lengths (first gauge length sections and second gauge length sections). The first sections have longer gauge lengths for high SN ratio detection, while the second sections have shorter gauge lengths for high spatial resolution. This segmentation allows the system to simultaneously utilize both long and short gauge length characteristics for comprehensive event detection and precise positioning.
2Measurement precision
If a short gauge length section is used in DAS, then the spatial resolution is improved, but the signal intensity decreases and SN ratio deteriorates
Solution Approach 1:
The invention merges the detection results from both first gauge length sections (long) and second gauge length sections (short). The signal selection unit selects appropriate sections based on signal features, and the section estimation unit determines the event position by combining information from both types of sections. This merging allows the system to overcome the limitations of using either long or short gauge lengths alone.
3Measurement precision
If the gauge length is shortened to improve spatial resolution, then event position specification capability is improved, but event detection accuracy deteriorates due to low SN ratio
Solution Approach 1:
The signal selection unit acts as an intermediary that selects which gauge length sections to use based on signal features. When events occur, the system can select first gauge length sections for reliable detection and second gauge length sections for precise positioning. The section estimation unit then integrates this selected information to determine the final event position with both accuracy and precision.
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 high spatial resolution detection of events by combining signals from long and short gauge length sections, improving the accuracy of event positioning within the distributed acoustic sensing system.
Implementation Method 1
applies probe light to an optical fiber, receives reflected light or transmitted light from the optical fiber, and detects a state of a sound wave or vibration acting on the optical fiber
Data Source
AI summary
A signal acquisition unit acquires a plurality of signal groups acquired based on backscattered light from a plurality of long gauge length sections and a plurality of signal groups acquired based on backscattered light from a plurality of short gauge length sections, which are set in an optical fiber used for distributed acoustic sensing. A signal selection unit selects a long gauge length section based on a first signal feature of each of signal groups of the plurality of long gauge length sections, and selects a plurality of short gauge length sections corresponding to the selected long gauge length section. A section estimation unit determines one short gauge length section, as a section in which an event has occurred, based on a second signal feature of each of signal groups of the plurality of selected short gauge length sections.