Distributed Fiber Optic Sensing for Vehicle Speed and Size
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Solution Overview
Problem
Current distributed fiber optic sensing systems face a trade-off between achieving high spatial resolution and long reach due to the limitations of pulse peak power and temporal width, which restricts their ability to accurately monitor vehicle speed, direction, and size in real-time.
Innovation Solution
The system employs a novel optical fiber layout and temporal measurement approach that allows for high accuracy spatial measurement without requiring short pulses, enabling continuous real-time monitoring of vehicle properties such as speed, direction, and axle width, and can be adapted for multi-lane detection and longer pulse widths.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If short pulses are used to achieve high spatial resolution, then measurement precision is improved, but pulse peak power requirements increase and temporal width constraints limit the system
Solution Approach 1:
The patent transitions from spatial domain measurement to temporal domain measurement. Instead of using short pulses to achieve spatial resolution, the system uses the temporal distribution of vibrations along the fiber and maps this temporal information to spatial information through geometric relationships. This dimensional transformation allows achieving spatial resolution without the power and temporal width constraints of short pulses.
Solution Approach 2:
The patent changes the measurement parameter from spatial domain to temporal domain. By measuring the temporal distribution of vibrations and using geometric relationships to infer spatial properties, the system achieves high spatial resolution while using longer pulses with lower peak power requirements. This parameter transformation resolves the contradiction between spatial resolution and pulse peak power.
2Productivity
If the sensing fiber is positioned beneath the roadway, then continuous real-time monitoring is enabled, but the ability to accurately determine vehicle geometric properties from vibration signals becomes challenging
Solution Approach 1:
The patent introduces geometric relationships as an intermediary between the vibration signals and vehicle properties. By establishing mathematical geometric models that relate the temporal vibration patterns to spatial vehicle characteristics, the system can accurately determine vehicle geometric properties even when the fiber is positioned beneath the roadway, resolving the measurement challenge.
Solution Approach 2:
The patent uses temporal domain analysis to overcome the spatial positioning challenge. By transforming the problem from directly measuring spatial vehicle properties to analyzing temporal vibration distributions and mapping them through geometric relationships, the system achieves accurate geometric property detection despite the fiber's subsurface position.
3Power
If longer pulse widths are used, then the system can operate with lower peak power, but spatial resolution deteriorates in conventional systems
Solution Approach 1:
The patent fundamentally changes the measurement approach from spatial domain to temporal domain. This allows using longer pulses with lower peak power while maintaining effective resolution through temporal analysis of vibration distributions. The temporal width information is transformed into spatial information via geometric relationships, resolving the contradiction between pulse width and spatial resolution.
Solution Approach 2:
The patent changes the primary measurement parameter from spatial to temporal. By measuring temporal vibration distributions and using geometric models to infer spatial properties, the system achieves effective spatial resolution with longer pulses and lower peak power, directly resolving the power-resolution trade-off.
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 solution provides enhanced accuracy in vehicle speed and direction calculations and allows for the detection of motorcycles and axle number, overcoming the limitations of existing systems by using a temporal measurement method that maintains high spatial resolution without the constraints of short pulse energy.
Implementation Method 1
distributed fiber optic sensing systems (DFOS) that advantageously enable and/or facilitate continuous, real-time monitoring and identification of vehicles traversing a highway/roadway under which the DFOS sensing fiber is positioned
Data Source
AI summary
Aspects of the present disclosure describe distributed fiber optic sensing (DFOS) systems, methods, and structures that advantageously enable and/or facilitate the continuous, real-time monitoring and identification vehicle speed, vehicle direction, vehicle axle width, vehicle type, total number of vehicle axles, and vehicle count. The DFOS sensing fiber is advantageously positioned underneath a roadway/highway in a novel arrangement/layout and temporal measurements are made to provide vehicle identification.