Optical Fiber Sensor Location Correction
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Solution Overview
Problem
Optical fiber cables installed along expressways or railroad tracks often have varying installation states, leading to discrepancies between sensed and actual locations, with differences potentially exceeding 10% over longer distances, affecting the accuracy of environmental monitoring.
Innovation Solution
An optical fiber sensor system that transmits optical pulse signals through the cable, analyzes backscattered light for environmental changes, and corrects sensing locations based on identified occurrence locations and installation information, using a device body with a sensor unit, analysis unit, and location correction processing to synchronize sensing data with actual cable positions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of stationary object
If optical fiber cables are installed along expressways or railroad tracks for environmental monitoring, then the monitoring coverage is improved, but the accuracy of location sensing deteriorates due to installation variations such as deflection and extra length
Solution Approach 1:
The system uses feedback by comparing the sensed location (based on optical pulse propagation time) with the actual physical location (from installation records). The difference is calculated and used to correct subsequent sensing measurements, creating a closed-loop system that compensates for installation variations.
Solution Approach 2:
The system changes the parameter of location measurement by introducing a correction value that adjusts the sensed location. Instead of directly using the propagation time-based location, the system adds a correction parameter derived from installation information to obtain the accurate physical location.
2Length of stationary object
If the distance of optical fiber cable increases to expand monitoring area, then the coverage is improved, but the location sensing accuracy deteriorates as the difference between sensed and actual locations becomes larger
Solution Approach 1:
The system performs preliminary action by recording installation information (actual physical locations of cables) before using the cable for sensing. This pre-established reference data is used to correct sensing measurements, allowing the system to compensate for location errors even over long distances.
Solution Approach 2:
The system introduces an intermediary element - the correction value - that mediates between the sensed location and the actual physical location. This correction value, derived from installation information, acts as a bridge to reconcile the discrepancy caused by cable installation variations.
3Device complexity
If optical pulse propagation time is used to determine sensing location, then the measurement process is simplified, but location accuracy deteriorates due to installation variations like deflection and extra length
Solution Approach 1:
The system introduces an intermediary correction value that reconciles the simple propagation time measurement with the actual physical location. This correction value, derived from installation information, acts as a mediator that bridges the gap between the simplified measurement method and the required accuracy.
Solution Approach 2:
The system replaces the purely physical/mechanical measurement approach (relying solely on optical pulse propagation time) with a hybrid approach that incorporates information processing. By substituting the mechanical assumption of direct cable-path correspondence with computational correction, the system achieves higher accuracy.
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
The system effectively compensates for discrepancies between sensed and actual locations, enhancing the accuracy of environmental monitoring by correcting sensing locations based on environmental and installation data, thereby improving the precision of vibration, sound, and other parameter measurements.
Implementation Method 1
measuring intensity change of backscattered light that returns in the opposite direction to the direction of the optical pulses transmitted
Implementation Method 2
The BOTDR measures backscattered light referred to as Brillouin scattered light. Since the Brillouin scattered light has characteristics that, when a strain or the like is applied to an optical fiber, a frequency shift occurs
Implementation Method 3
calculation based on propagation time from an optical pulse is transmitted until backscattered light is measured
Data Source
AI summary
According to one example embodiment, an optical fiber sensor includes an optical fiber cable and a device body configured to cause an optical pulse signal to be incident on the optical fiber cable and identify, from intensity change of backscattered light of the incident optical pulse signal and an arrival time of the backscattered light, a prescribed environmental change having occurred in a vicinity of the optical fiber cable and an occurrence location of the environmental change, in which the device body performs correction of a sensing location on the optical fiber cable, based on environmental change information including the identified occurrence location and installation location information of the optical fiber cable.