Underground Optical Fiber Cable Localization via DFOS and TDOA
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Solution Overview
Problem
Current methods for localizing underground optical fiber cables are often inaccurate and non-destructive methods are lacking, making it difficult for telecommunications carriers to efficiently maintain and repair these cables.
Innovation Solution
The use of distributed fiber optic sensing (DFOS) systems and time difference of arrival (TDOA) data from impulsive surface vibrations to solve non-linear least square optimization problems for precise localization of underground optical fiber cables, without the need for synchronization between the vibration source and receiver, employing man-made vibrations for determination.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If prior information from construction maps or notes is used to locate underground optical fiber cables, then the localization process is simple and quick, but the accuracy and reliability of cable location information deteriorates due to inaccuracies or outdated data
Solution Approach 1:
The patent replaces manual inspection methods and traditional electromagnetic locating devices with a distributed fiber optic sensing system that uses optical signals. The DFOS system detects acoustic vibrations along the fiber cable to precisely locate underground cable positions, achieving high measurement precision without relying on outdated construction maps or simple electromagnetic methods.
Solution Approach 2:
The patent introduces an intermediary acoustic vibration source that generates detectable signals in the ground. These vibrations propagate through the soil and are detected by the DFOS system along the optical fiber, enabling precise cable localization. The vibration source acts as a mediator between the localization system and the underground cables, providing accurate positional information without direct contact or excavation.
2Reliability
If seismic or electromagnetic reflection methods are used to estimate underground object location, then non-destructive localization is achieved, but the precision and reliability of cable localization deteriorates due to signal attenuation and interference
Solution Approach 1:
The patent replaces seismic and electromagnetic reflection methods with distributed fiber optic sensing technology. Instead of using acoustic waves or electromagnetic signals that suffer from attenuation and interference, the system uses optical signals transmitted through the fiber cable itself to detect acoustic vibrations. This substitution significantly improves both the reliability and precision of underground cable localization by utilizing the fiber optic cable as both the sensing medium and the signal transmission path.
3Measurement precision
If synchronization between vibration source and DFOS receiver is implemented, then signal correlation is improved, but system complexity and operational difficulty increases
Solution Approach 1:
The patent implements a self-synchronized system where the DFOS receiver automatically detects and correlates vibrations without requiring external synchronization signals. The system uses the inherent temporal characteristics of the detected acoustic signals to determine time difference of arrival (TDOA) between multiple fiber segments, enabling precise localization without complex synchronization mechanisms. This self-service approach maintains high measurement precision while significantly simplifying system operation.
4Productivity
If manual inspection and repair based on incomplete location knowledge is performed, then equipment and time are saved, but productivity and maintenance efficiency deteriorates due to difficulty in locating exact cable positions
Solution Approach 1:
The patent uses an acoustic vibration source as an intermediary to rapidly locate underground cables. By generating controlled vibrations and detecting their propagation along the fiber optic cable, the system quickly identifies exact cable positions and fault locations. This eliminates the need for time-consuming manual inspection and trial-and-error repair methods, significantly improving maintenance productivity while reducing the time required to locate and repair cable issues.
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 allows for high-precision, non-destructive localization of underground optical fiber cables with sub-meter-level accuracy, enabling efficient maintenance and visualization of cable positions and orientations.
Implementation Method 1
utilize distributed fiber optic sensing (DFOS) and time difference of arrival (TDOA) data associated with received signals of impulsive surface vibrations to localize the underground optical fiber cable
Implementation Method 2
utilize only TDOA information of received signals of impulsive surface vibrations to determine such localizations
Data Source
AI summary
A method for the non-destructive localization of underground optical fiber cables that utilizes distributed fiber optic sensing (DFOS) and time difference of arrival (TDOA) data associated with received signals of impulsive surface vibrations to localize the underground optical fiber cable by solving non-linear least square optimization problem(s). The method utilizes only TDOA information of received signals of impulsive surface vibrations to determine such localizations and does not require synchronization between a vibration source and DFOS receiver. The method may employ man-made impulsive vibrations to determine the localization. In operation the method involves 1) impulse-like vibration excitation and signal collection; 2) TDOA estimation of the received signals from DFOS; and 3) non-linear least square optimization applied to the TDOA information for underground optical fiber localization.