Rayleigh Phase-OTDR Correlation Diversity Bias Removal
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Distributed acoustic sensing systems using Rayleigh backscattering in optical fibers are susceptible to phase noise and phase discontinuity due to Rayleigh fading, which affects the accuracy of acoustic vibration detection.
Innovation Solution
The system employs correlation-based diversity combining and bias removal techniques by computing delay interferometric products from different polarizations and frequencies, aligning vectors in phase, and using arc centering algorithms to mitigate phase noise and discontinuities, thereby enhancing the signal-to-noise ratio and accuracy of acoustic vibration detection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If Rayleigh backscatter-based DAS systems are used for distributed acoustic sensing, then real-time monitoring of multiple dynamic events is achieved, but phase noise and phase discontinuity occur due to Rayleigh fading
Solution Approach 1:
The patent combines multiple interferometric products obtained from different polarizations and/or frequencies through correlation-based diversity combining. By merging these diverse signal sources and aligning their vectors in phase, the system achieves improved signal-to-noise ratio and eliminates phase discontinuities caused by Rayleigh fading, while maintaining real-time monitoring capability
Solution Approach 2:
The patent changes the parameters of the interferometric products by obtaining them at different polarizations and/or frequencies. This parameter diversification allows the system to capture multiple versions of the acoustic signal, which are then combined to produce a more reliable phase measurement that is immune to Rayleigh fading effects
2Measurement precision
If multiple delay interferometric products are computed and combined, then signal-to-noise ratio is improved, but system complexity increases
Solution Approach 1:
The patent performs preliminary actions by obtaining multiple interferometric products from different polarizations and frequencies before the final combination step. This preliminary diversification of signal sources enables the subsequent correlation-based combining to achieve high signal-to-noise ratio without requiring complex real-time processing during the measurement phase
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
This approach significantly improves the amplitude and signal-to-noise ratio of the detected acoustic vibrations, reducing phase noise and discontinuities, and providing more accurate measurements of longitudinal vibrations in optical fibers.
Implementation Method 1
Rayleigh backscatter-based DAS systems
Implementation Method 2
a receiver unit that detects Rayleigh backscatter from the optical fiber
Implementation Method 3
Rayleigh backscatter-based DAS systems
Implementation Method 4
computing a plurality of delay interferometric products based on different combinations of polarizations and/or frequencies
Implementation Method 5
adding the interferometric products in phase by aligning their vectors using correlation
Data Source
AI summary
Aspects of the present disclosure describe systems, methods and apparatus for improving the performance of Rayleigh-based phase-OTDR with correlation-based diversity combining and bias removal.