GB2406376A - Surveillance system including serial array of fiber optic point sensors - Google Patents

Surveillance system including serial array of fiber optic point sensors Download PDF

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Publication number
GB2406376A
GB2406376A GB0322351A GB0322351A GB2406376A GB 2406376 A GB2406376 A GB 2406376A GB 0322351 A GB0322351 A GB 0322351A GB 0322351 A GB0322351 A GB 0322351A GB 2406376 A GB2406376 A GB 2406376A
Authority
GB
United Kingdom
Prior art keywords
sensor
fibre
optic
surveillance system
path
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Withdrawn
Application number
GB0322351A
Other versions
GB0322351D0 (en
Inventor
David John Hill
Philip John Nash
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Qinetiq Ltd
Original Assignee
Qinetiq Ltd
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Qinetiq Ltd filed Critical Qinetiq Ltd
Priority to GB0322351A priority Critical patent/GB2406376A/en
Publication of GB0322351D0 publication Critical patent/GB0322351D0/en
Priority to US10/573,671 priority patent/US7965909B2/en
Priority to DE602004005224T priority patent/DE602004005224T2/en
Priority to EP04768620A priority patent/EP1664682B1/en
Priority to PCT/GB2004/004076 priority patent/WO2005031270A1/en
Priority to JP2006527475A priority patent/JP4526537B2/en
Priority to AT04768620T priority patent/ATE356337T1/en
Priority to CNB2004800276209A priority patent/CN100516781C/en
Publication of GB2406376A publication Critical patent/GB2406376A/en
Priority to IL174411A priority patent/IL174411A/en
Withdrawn legal-status Critical Current

Links

Classifications

    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01L—MEASURING FORCE, STRESS, TORQUE, WORK, MECHANICAL POWER, MECHANICAL EFFICIENCY, OR FLUID PRESSURE
    • G01L1/00—Measuring force or stress, in general
    • G01L1/24—Measuring force or stress, in general by measuring variations of optical properties of material when it is stressed, e.g. by photoelastic stress analysis using infrared, visible light, ultraviolet
    • G01L1/242—Measuring force or stress, in general by measuring variations of optical properties of material when it is stressed, e.g. by photoelastic stress analysis using infrared, visible light, ultraviolet the material being an optical fibre
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01D—MEASURING NOT SPECIALLY ADAPTED FOR A SPECIFIC VARIABLE; ARRANGEMENTS FOR MEASURING TWO OR MORE VARIABLES NOT COVERED IN A SINGLE OTHER SUBCLASS; TARIFF METERING APPARATUS; MEASURING OR TESTING NOT OTHERWISE PROVIDED FOR
    • G01D5/00—Mechanical means for transferring the output of a sensing member; Means for converting the output of a sensing member to another variable where the form or nature of the sensing member does not constrain the means for converting; Transducers not specially adapted for a specific variable
    • G01D5/26—Mechanical means for transferring the output of a sensing member; Means for converting the output of a sensing member to another variable where the form or nature of the sensing member does not constrain the means for converting; Transducers not specially adapted for a specific variable characterised by optical transfer means, i.e. using infrared, visible, or ultraviolet light
    • G01D5/32—Mechanical means for transferring the output of a sensing member; Means for converting the output of a sensing member to another variable where the form or nature of the sensing member does not constrain the means for converting; Transducers not specially adapted for a specific variable characterised by optical transfer means, i.e. using infrared, visible, or ultraviolet light with attenuation or whole or partial obturation of beams of light
    • G01D5/34—Mechanical means for transferring the output of a sensing member; Means for converting the output of a sensing member to another variable where the form or nature of the sensing member does not constrain the means for converting; Transducers not specially adapted for a specific variable characterised by optical transfer means, i.e. using infrared, visible, or ultraviolet light with attenuation or whole or partial obturation of beams of light the beams of light being detected by photocells
    • G01D5/353—Mechanical means for transferring the output of a sensing member; Means for converting the output of a sensing member to another variable where the form or nature of the sensing member does not constrain the means for converting; Transducers not specially adapted for a specific variable characterised by optical transfer means, i.e. using infrared, visible, or ultraviolet light with attenuation or whole or partial obturation of beams of light the beams of light being detected by photocells influencing the transmission properties of an optical fibre
    • G01D5/35303—Mechanical means for transferring the output of a sensing member; Means for converting the output of a sensing member to another variable where the form or nature of the sensing member does not constrain the means for converting; Transducers not specially adapted for a specific variable characterised by optical transfer means, i.e. using infrared, visible, or ultraviolet light with attenuation or whole or partial obturation of beams of light the beams of light being detected by photocells influencing the transmission properties of an optical fibre using a reference fibre, e.g. interferometric devices
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01D—MEASURING NOT SPECIALLY ADAPTED FOR A SPECIFIC VARIABLE; ARRANGEMENTS FOR MEASURING TWO OR MORE VARIABLES NOT COVERED IN A SINGLE OTHER SUBCLASS; TARIFF METERING APPARATUS; MEASURING OR TESTING NOT OTHERWISE PROVIDED FOR
    • G01D5/00—Mechanical means for transferring the output of a sensing member; Means for converting the output of a sensing member to another variable where the form or nature of the sensing member does not constrain the means for converting; Transducers not specially adapted for a specific variable
    • G01D5/26—Mechanical means for transferring the output of a sensing member; Means for converting the output of a sensing member to another variable where the form or nature of the sensing member does not constrain the means for converting; Transducers not specially adapted for a specific variable characterised by optical transfer means, i.e. using infrared, visible, or ultraviolet light
    • G01D5/32—Mechanical means for transferring the output of a sensing member; Means for converting the output of a sensing member to another variable where the form or nature of the sensing member does not constrain the means for converting; Transducers not specially adapted for a specific variable characterised by optical transfer means, i.e. using infrared, visible, or ultraviolet light with attenuation or whole or partial obturation of beams of light
    • G01D5/34—Mechanical means for transferring the output of a sensing member; Means for converting the output of a sensing member to another variable where the form or nature of the sensing member does not constrain the means for converting; Transducers not specially adapted for a specific variable characterised by optical transfer means, i.e. using infrared, visible, or ultraviolet light with attenuation or whole or partial obturation of beams of light the beams of light being detected by photocells
    • G01D5/353—Mechanical means for transferring the output of a sensing member; Means for converting the output of a sensing member to another variable where the form or nature of the sensing member does not constrain the means for converting; Transducers not specially adapted for a specific variable characterised by optical transfer means, i.e. using infrared, visible, or ultraviolet light with attenuation or whole or partial obturation of beams of light the beams of light being detected by photocells influencing the transmission properties of an optical fibre
    • G01D5/35383—Mechanical means for transferring the output of a sensing member; Means for converting the output of a sensing member to another variable where the form or nature of the sensing member does not constrain the means for converting; Transducers not specially adapted for a specific variable characterised by optical transfer means, i.e. using infrared, visible, or ultraviolet light with attenuation or whole or partial obturation of beams of light the beams of light being detected by photocells influencing the transmission properties of an optical fibre using multiple sensor devices using multiplexing techniques
    • G—PHYSICS
    • G08—SIGNALLING
    • G08B—SIGNALLING OR CALLING SYSTEMS; ORDER TELEGRAPHS; ALARM SYSTEMS
    • G08B13/00—Burglar, theft or intruder alarms
    • G08B13/18—Actuation by interference with heat, light, or radiation of shorter wavelength; Actuation by intruding sources of heat, light, or radiation of shorter wavelength
    • G08B13/181—Actuation by interference with heat, light, or radiation of shorter wavelength; Actuation by intruding sources of heat, light, or radiation of shorter wavelength using active radiation detection systems
    • G08B13/183—Actuation by interference with heat, light, or radiation of shorter wavelength; Actuation by intruding sources of heat, light, or radiation of shorter wavelength using active radiation detection systems by interruption of a radiation beam or barrier
    • G08B13/186—Actuation by interference with heat, light, or radiation of shorter wavelength; Actuation by intruding sources of heat, light, or radiation of shorter wavelength using active radiation detection systems by interruption of a radiation beam or barrier using light guides, e.g. optical fibres

Abstract

A fiber optic sensor for a perimeter surveillance system 10. The sensor 15 comprises: a series array of fiber optic point sensors 16A, 16B, 16C, 16D,..., in which successive point sensors are linked by a distributed fibre optic sensors 18A, 18B, 18C, 18D,..., a data link 14, and an interrogation unit 12. This unit may analyse optical signals received from the sensor 15 to establish the position of an intruder event, or the position at which an object or person has crossed a path defined by the length of the sensor that may be positioned below the ground.

Description

FIBRE-OPTIC SURVEILLANCE SYSTEM
The present invention relates to fibre-optic surveillance systems.
It is known to use optical fibres as sensing elements to detect pressure, strain etc. with conditions external to an optical fibre being inferred from changes in characteristics, such as amplitude, frequency or polarization, in light output from the fibre. An example is the pressure sensor described in European Patent number 0 365 062.
One approach to perimeter surveillance is to arrange a single length of optical fibre below ground level around a perimeter to be monitored, and to couple radiation from an LED or laser-diode into the fibre. Pressure on the fibre due to the weight of a person, vehicle or other object crossing a perimeter defined by the fibre causes a change in the amount of radiation back-scattered within the fibre (due to bending of the fibre) , and hence the presence of an intruder can be detected.
However, such a system has three significant disadvantages, namely (i) the position at which an intruder crosses the perimeter cannot be determined accurately, (ii) a significant false-alarm rate and (iii) no information is given about the nature if the intruding person or object.
According to a first aspect of the invention, these problems are ameliorated by a fibre-optic sensor for a surveillance system, in which the sensor comprises a serial array of fibre-optic point sensors, wherein successive point sensors are linked by a distributed fibre-optic sensor.
To provide positional information on intruders events, the sensor is preferably comprised in a fibre-optic surveillance system which further comprises an interrogation system (12) for analysing optical signals received from the sensor to establish the position of an intruder event.
Corresponding to the first aspect of the invention, a second aspect thereof provides a method of establishing the position at which an object moving on a surface crosses a closed path, or an open path of fixed length, thereon, characterized in that the method comprises the steps of (i) positioning a sensor according to claim 1 on or below said path; and (ii) analysing optical signals received from the sensor to establish the position of the object along the path, or the position at which the object has crossed said path.
An embodiment of the invention are described below by way of example only and with reference to the accompanying drawing in which schematically illustrates a fibre-optic perimeter surveillance system according to the invention.
In Figure 1, a fibre-optic perimeter surveillance system according to the invention is indicated generally by 10. The system 10 comprises a series of fibre-optic point sensors 16A, 16B, 16C, 16D, , 16N (in this example, geophones) optically linked by a series of distributed fibre-optic sensors 18B, 18C, 18D, , 18N to form a fibre-optic sensor array 15. A data link 14 couples the geophone 16A to an interrogation unit 12. The data link 14 may be a length of optical fibre, so that optical signals are passed to the interrogation unit 12, or alternatively it may comprise a detector which converts optical signals into electrical signals and either a fixed electrical, or wireless, link to the interrogation unit 12.
The distributed fibre-optic sensors 18B, 18C, 18D, , 18N each have a physical length of 100m. There are 250 geophones in the array 15, so that the separation of geophones 16A,16N may be up to approximately 24.9km.
Each of the geophones 16A, 16B, 16C, 16D, , 16N comprises approximately 100m of optical fibre wound onto a flexural disc, and is able to measure acceleration and displacement via strain induced in the fibre. Each of the distributed sensors 18B, 18C, 18D, , 18N comprises 100m of optical fibre packaged within a cable and can measure pressure on, or bend of, the cable, also via strain induced on the fibre.
The array 15 may be arranged in any desired configuration, for example it may be arranged around a closed path to provide perimeter surveillance for e.g. a building; alternatively it may be arranged in a linear manner to provide information on the location of a person/object crossing a straight line defined by the array 15.
The system 10 operates as follows. When a person or object crosses a line or perimeter on or underneath which the array 15 is positioned, radiation within a distributed fibre-optic sensor corresponding to the location where the person/object crosses is reflected back to geophone 16A and a corresponding signal giving approximate location is passed to the interrogation unit 12. More particularly the interrogation unit 12 is able to identify that a crossing has occurred somewhere along the length of the array 15. Radiation is also reflected back from the geophones at either end of that distributed sensor, and corresponding signals are also passed to the interrogation unit 12. The interrogation unit 12 carries out triangulation of the signals received from the distributed sensor and the geophones at either end of it to accurately determine the location along the array at which the person/object has crossed on the basis of the time at which signals are received. By using data from both types of sensor, it is possible to provide much more accurate classification of the person/object than is achievable through use of one sensor type alone. Improved classification results in a lower false-alarm rate.
In the example system 10, the point fibre-optic sensors are geophones, however other types of fibre-optic point sensor may be used.
The number of point and distributed sensors may vary according to both the length of a perimeter or path which is desired to be monitored, and the accuracy with which it is desired to locate intruder events. The simplest fibre-optic sensor of the invention would comprise a single distributed sensor having a point sensor at each end.

Claims (3)

1. A fibre-optic sensor (15) for a surveillance system (10) characterized in that the sensor comprises a serial array (15) of fibre-optic point sensors (16), in which successive point sensors are linked by a distributed fibre-optic sensor (18).
2. A fibre-optic surveillance system (10) characterized in that the system comprises a fibre optic sensor (15) according to claim 1 and an interrogation system (12) for analysing optical signals received from the sensor to establish the position of an intruder event.
3. A method of establishing the position at which an object moving on the earth's surface crosses a closed path, or an open path of fixed length, thereon, characterized in that the method comprises the steps of (i) positioning a sensor according to claim 1 on or below said path; and (ii) analysing optical signals received from the sensor to establish the position of the object along the path, or the position at which the object has crossed said path.
GB0322351A 2003-09-24 2003-09-24 Surveillance system including serial array of fiber optic point sensors Withdrawn GB2406376A (en)

Priority Applications (9)

Application Number Priority Date Filing Date Title
GB0322351A GB2406376A (en) 2003-09-24 2003-09-24 Surveillance system including serial array of fiber optic point sensors
CNB2004800276209A CN100516781C (en) 2003-09-24 2004-09-24 Fiber optic surveillance system
PCT/GB2004/004076 WO2005031270A1 (en) 2003-09-24 2004-09-24 Fibre-optic surveillance system
DE602004005224T DE602004005224T2 (en) 2003-09-24 2004-09-24 FIBER OPTICAL MONITORING SYSTEM
EP04768620A EP1664682B1 (en) 2003-09-24 2004-09-24 Fibre-optic surveillance system
US10/573,671 US7965909B2 (en) 2003-09-24 2004-09-24 Fibre-optic surveillance system
JP2006527475A JP4526537B2 (en) 2003-09-24 2004-09-24 Optical fiber monitoring system
AT04768620T ATE356337T1 (en) 2003-09-24 2004-09-24 FIBER OPTICAL MONITORING SYSTEM
IL174411A IL174411A (en) 2003-09-24 2006-03-20 Fibre-optic surveillance system

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
GB0322351A GB2406376A (en) 2003-09-24 2003-09-24 Surveillance system including serial array of fiber optic point sensors

Publications (2)

Publication Number Publication Date
GB0322351D0 GB0322351D0 (en) 2003-10-22
GB2406376A true GB2406376A (en) 2005-03-30

Family

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Family Applications (1)

Application Number Title Priority Date Filing Date
GB0322351A Withdrawn GB2406376A (en) 2003-09-24 2003-09-24 Surveillance system including serial array of fiber optic point sensors

Country Status (9)

Country Link
US (1) US7965909B2 (en)
EP (1) EP1664682B1 (en)
JP (1) JP4526537B2 (en)
CN (1) CN100516781C (en)
AT (1) ATE356337T1 (en)
DE (1) DE602004005224T2 (en)
GB (1) GB2406376A (en)
IL (1) IL174411A (en)
WO (1) WO2005031270A1 (en)

Cited By (2)

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WO2010071926A1 (en) * 2008-12-22 2010-07-01 Perimeter Security Industries Pty Ltd Intruder detection system
US9759824B2 (en) 2011-12-23 2017-09-12 Optasense Holdings Limited Seismic monitoring

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GB0401053D0 (en) * 2004-01-17 2004-02-18 Qinetiq Ltd Improvements in and relating to accelerometers
US7672545B2 (en) * 2005-05-23 2010-03-02 Lxdata Inc. Methods and apparatuses for obtaining information regarding sensors in optical paths
EP2300299B1 (en) 2008-06-17 2017-01-18 Weir - Jones Engineering Consultants Ltd. System and method for detecting rock fall
BRPI1012029B1 (en) 2009-05-27 2020-12-08 Optasense Holdings Limited method and system for monitoring and controlling a borehole process below
US8345229B2 (en) * 2009-09-28 2013-01-01 At&T Intellectual Property I, L.P. Long distance optical fiber sensing system and method
GB0917150D0 (en) * 2009-09-30 2009-11-11 Qinetiq Ltd Phase based sensing
GB201112161D0 (en) * 2011-07-15 2011-08-31 Qinetiq Ltd Portal monitoring
CA2858226C (en) * 2011-12-15 2018-04-24 Shell Internationale Research Maatschappij B.V. Detecting broadside acoustic signals with a fiber optical distributed acoustic sensing (das) assembly
CN103489275B (en) * 2013-08-29 2016-12-28 广东复安科技发展有限公司 A kind of monitoring circuit improving optical fiber distance monitoring positioning precision and method
CN103743421B (en) * 2013-12-31 2016-05-18 上海华魏光纤传感技术有限公司 Based on many method for sensing of single optical fibre
JP7201102B2 (en) * 2019-11-25 2023-01-10 日本電気株式会社 Position detection device and position detection method
US11619541B2 (en) * 2020-04-14 2023-04-04 Nec Corporation Vehicle speed, direction, and size measurement using temporal distributed fiber optic sensing
CN112432694B (en) * 2020-11-06 2021-11-02 中冶建筑研究总院有限公司 Industrial plant power monitoring method based on distributed optical fiber sensor

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WO2010071926A1 (en) * 2008-12-22 2010-07-01 Perimeter Security Industries Pty Ltd Intruder detection system
AU2009311054A1 (en) * 2008-12-22 2010-07-08 Perimeter Security Industries Pty Ltd Intruder detection system
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GB2473785A (en) * 2008-12-22 2011-03-23 Perimeter Security Ind Pty Ltd Intruder detection system
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Also Published As

Publication number Publication date
IL174411A (en) 2010-04-29
JP4526537B2 (en) 2010-08-18
EP1664682A1 (en) 2006-06-07
CN1856694A (en) 2006-11-01
WO2005031270A1 (en) 2005-04-07
CN100516781C (en) 2009-07-22
DE602004005224T2 (en) 2007-06-21
GB0322351D0 (en) 2003-10-22
DE602004005224D1 (en) 2007-04-19
US20060257066A1 (en) 2006-11-16
JP2007506960A (en) 2007-03-22
ATE356337T1 (en) 2007-03-15
IL174411A0 (en) 2006-08-01
EP1664682B1 (en) 2007-03-07
US7965909B2 (en) 2011-06-21

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