Fiber Bragg Grating Sensor Sleeve for Perimeter Intrusion Detection
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current perimeter intrusion detection systems (PIDS) are susceptible to false alarms due to nuisance events such as rain, birds, or seismic vibrations from aircraft, which can lead to inaccurate measurements and reduced robustness, especially in critical infrastructure and high-security areas.
Innovation Solution
A fiber Bragg grating (FBG) sensor structure is developed, comprising an optical fiber with FBGs integrated into a resilient metallic sleeve that transfers vibrations and strain, allowing the central wavelength to vary under amplitude and frequency changes, enabling more accurate detection of intrusions by an interrogator system.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If traditional PIDS sensors (microphonic, microwave, seismic) are used, then the system can detect intrusions, but the system produces false alarms due to nuisance events like rain, birds, or seismic vibrations
Solution Approach 1:
The patent changes the sensing parameter from general vibration detection to specific wavelength shift detection using FBG sensors. The FBG sensor measures central wavelength shifts caused by strain and temperature, providing more specific and reliable detection parameters that differentiate between genuine intrusions and nuisance events like rain or bird activity.
Solution Approach 2:
The patent replaces traditional mechanical sensors (microphonic, seismic) with optical fiber-based FBG sensors. This substitution eliminates the need for electronic components in harsh environments and provides immunity to electromagnetic interference, thereby improving reliability and reducing false alarms while maintaining intrusion detection capability.
2Measurement precision
If FBG sensors are used to improve detection accuracy, then measurement precision improves, but the device complexity increases due to the need for wavelength interrogation systems
Solution Approach 1:
The patent uses optical copying principles where the FBG sensor reflects specific wavelengths of light back to the interrogation system. The wavelength information is copied and analyzed remotely, allowing precise measurements without complex electronic components at the sensing location, thus improving measurement precision while managing device complexity through remote interrogation.
3Measurement precision
If the optical fiber is directly coupled to the sleeve structure, then vibration transfer efficiency improves, but the sensor becomes more sensitive to nuisance vibrations
Solution Approach 1:
The patent applies local quality by creating a coupling zone between the optical fiber and sleeve structure where selective vibration transfer occurs. The coupling mechanism is designed to transfer specific frequency ranges associated with intrusions while filtering out high-frequency nuisance vibrations, achieving both efficient vibration transfer and immunity to harmful factors through localized structural design.
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 FBG sensor structure enhances detection accuracy by differentiating between genuine intrusion signals and nuisance events, providing robust and reliable perimeter security with reduced false alarms and improved sensitivity.
Implementation Method 1
A fiber Bragg grating (FBG) is a type of distributed Bragg reflector constructed in a short segment of optical fiber that reflects particular wavelengths of light and transmits all others
Implementation Method 2
a sleeve structure capable of transferring vibrations and/or strain along a length thereof; wherein the optical fiber portion is coupled to the sleeve structure such that the central wavelength of the FBG is variable under the transferred vibrations and/or strain
Data Source
AI summary
A Fiber Bragg grating (FBG) sensor structure, a method of fabricating a FBG sensor structure, and a method of employing a FBG sensor structure comprising an optical fiber portion having at least one FBG formed therein. The FBG sensor structure comprises an optical fiber portion having at least one FBG formed therein; and a sleeve structure capable of transferring vibrations and/or strain along a length thereof; wherein the optical fiber portion is coupled to the sleeve structure such that the central wavelength of the FBG, is variable under the transferred vibrations and/or strain.