Distributed Fibre Optic Virtual Fencing System

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HCTL Open Science and Technology Letters (HCTL Open STL)Edition on Wireless and Wired Networks: Advances and Applications,Volume 3, November 2013, e-ISSN: 2321-6980ISBN (Print): 978-1-62951-015-6

Distributed Fibre OpticVirtual Fencing System

Raj Gaurav Mishra

[email protected]

Abstract

This paper proposes the idea and concept of a virtual fencingsystem using fibre optics as a distributed intrusion detectionsensor system and its potential applications in wildlife and for-

est protection. In this paper, we have discussed different methods

implemented for intrusion detection and its localization using opti-cal fibre cables. Design and proposed future implementation of adistributed fibre optic virtual fencing system is discussed.

Keywords

Fibre Optics, Fibre Optic Sensors, Intrusion Detection System, Virtual FencingSystem, Review Interferometric Methods.

Introduction

Forests have direct effect on climate as they regulate the water cycle and playan important role in the purification of air. With increase in population, needof land for agriculture, grazing land, construction of houses, roads, railway

Hybrid Computing Technology Labs, India.

Raj Gaurav MishraDistributed Fibre Optic Virtual Fencing System.

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tracks and industrial developments has often been responsible for deforestation.Villagers residing near to the forests also are responsible for illegal deforestationlike logging and chopping of trees activities for fuel and sometimes for fodder.

Deforestation is responsible for the shrinkage of the wild habitat and foodresources for the wild animals causing human-animal conflicts. Human-animalconflict is a major concern for countries like India as natural habitat has beenincreasingly diminished by human development. Animals such as Tiger, Leop-ard, Bear and Elephant venture out of the forest, and cause damage to humansand their property, resulting in human-animal conflict. Many times animalssuch as elephants, tigers etc. being killed by running trains on railway linesthat crosses their natural trails or by the heavy vehicles passing by roads closer

to the protected forests, or wildlife sanctuaries.

The objective of this work is to develop a virtual fence system to fulfil thefollowing objectives:

1. Detecting the animals such as Tiger, Leopard, Bear and Elephant thatventure out of the forest and cause damage to humans and their properties,resulting in human-animal conflict. Use of some harmless deterrents suchas loud sounds to drive the animals back from the virtual animal fencingin case of intrusion and to prevent the animals coming outside the animalcorridor and forest.

2. Preventing animals such as elephants and tigers being killed by runningtrains by providing alarms on their trails that crosses the railway lines orthe heavy vehicles passing by the roads closer to the forests.

3. Detecting human intrusion and activities taking place from the wild lifesanctuary periphery to interiors of the forest to avoid illegal deforestationand poaching.

4. Monitoring the movement of forest guards in order to contact them andprovide necessary security and support to them against poachers, intrudersand wild animals.

5. Identifying other activities such as illegal digging (for laying traps forpoaching related activity) and forest mining within a protected wildlifesanctuary or a national park.

6. Detecting Forest Fires that rises from grasslands to the woods.

In this paper, we have proposed a conceptual design and configuration of avirtual fence based on fibre optic sensing system. There are many advantages

Raj Gaurav Mishra

Distributed Fibre Optic Virtual Fencing System.

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of using Fibre Optic cables as sensors, for instance it is an active distributedsensor that provides a large linear dynamic measurement range for the changesin strain or temperature directly over the buried fibre, it provides accuratemeasurements, a good sensitivity dependent on the deployed fibre cable length,it provides post signal processing of the analog output for the reduction offalse and nuisance alarm rates, insensitive to electromagnetic (EM) interference

and long deployable life of fibre optic cables makes the system run for a longerperiod. It provides intrinsic safety in hazardous environments will be light inweight and will have ability to optically multiplex with other fibre optic sensors.The system will work with low drain power supply and almost no restriction ofcommunication bandwidth.

In this paper, a conceptual design and configuration of a fibre optic sens-ing system for wildlife & forest protection applications is discussed. This paperis organized as section 2 presents literature review of optical fibre cable sensorsand different interferometric methods and techniques for distributed Intrusiondetection using optical fibre cable sensors, section 3 presents the proposedconfiguration and design of a fibre optic sensing system for wildlife and forest

protection and section 4 presents the conclusion and proposed future work toimplement the system.

Optical Fibre Cable Distributed SensorsIn the recent years, development of fibre optic cable sensors, related instru-mentation and techniques in the applications of real-time fibre optic perimeterintrusion detection systems has attracted greater interest [1]-[3].

There are different possible methods/techniques of setting up an intrusiondetection system using ordinary optical fibre cables and measurement instru-ments. Table1refers the different methods/techniques used by many researchersin their previous research work.

Interferometers are capable of sensing a variety of physical parameters such asdisplacement, strain, temperature, pressure, vibration etc. Laser source shownin the figures generates highly coherent (1550 nm) laser light. An interferometerdivides a coherent laser light into its two arms and measures the changes in thevelocity, intensity, phase, etc of the light in the first arm with reference to thesecond one.

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Techniques/Methods ReferencesUsing Optical Fibre Sagnac Je Bush et al.[4], M. Szustakowski et al. [5],

Interferometry Nian Fang et al. [6], Peilin Tao et al. [24],(Refer Figure1) Eric Udd[25]

Using Mach-Zehnder Kyoo Nam Choi et al. [13],Interferometry S. S. Mahmoud et al. [16]and [22],

(Refer Figure2) Tian Lan et al.[23], Li Wang et al.[26],N. M. S. Jahed et al. [27]

Using Michelson Interferometry John P. F. Wooler et al. [20],(Refer Figure3) Huaifei Xing et al.[21],

Roger I. Crickmore et al.[28]

Using Sagnac-Michelson A.A. Chtcherbakov et al. [29],(merged) Interferometry S. J. Spammer et al.[30]

(Refer Figure4)

Using other Nian Fang et al. [10],Interferometric methods G. B. Cogdell et al.[18], W. J. Bock et al. [30],

Alan D. Kersey [32], Yuan Libo[33]

Using -OTDRs J. C. Juarez et al.[11,12],(Phase-sensitivity using Kyoo Nam Choi et al. [14],

Optical Time-Domain Analysis) C. K. Madsen et al. [15](Refer Figure5)

Using CC-OTDRs Yannian Wang et al. [7],

(Complementary Correlation using M. Nazarathy et al. [34]Optical Time Domain Analysis)

(Refer Figure6)

Using B-OTDRs Marc Nikles[8], D. Inaudi et al.[35],(Brillouin Optical K. Hotate [36], T. Kurashima et al. [37],

Time Domain Analysis) T. Horiguchi et al. [38,39],(Refer Figure7) D. Garcus et al.[40], Ning Hua Zhu et al. [41]

Using P-OTDRs J. P. Hazan et al.[9],(Detecting Polarization B. Huttner et al.[42],

changes in the fibre) A. Rogers et al. [43],(Refer Figure8) M. Wuilpart et al.[44]

Using Custom C. Bryson et al.[17],Processors & Instrumentation Tian Lan et al. [23]

Table 1: Techniques/methods for intrusion detection using optical fibre cables

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The Sagnac interferometer [4]-[6], [24]-[25] fibre optic system is shown inthe figure 1. The interferometer has a 3 dB coupler and a Faraday rotatormirror (FRM). The sensor system uses a fibre cable instead of a complex loops

structure, and therefore is simple in structure, low in cost and stronger inenvironmental adaptability. FFT method can be used to calculate the phaseangle of the reflected signal to determine the intrusion. Its limitation is todetermine the crossing point (localization) of the intrusion. To remove thisproblem a Sagnac interferometer can be combined with other interferometers.Sagnac-Michelson Interferometric method[29]-[30]for intrusion detection andlocalization is shown in the figure4.

Figure 1: Optical Fibre Sagnac Interferometry [4]-[6], [24]-[25]

A Mach-Zehnder (MZ) interferometry [13]-[16], [22]-[23], [26]-[27] is an oldtechnique of optical measurements and an MZ interferometer can be formedusing two couplers connected with two arms of different optical lengths. Thelight is divided in two arms of the input coupler of the MZ interferometer andthey are later merged at the output coupler, connecting two different photo-detectors and a signal processing system to observe the relative phase-shift, asshown in figure2.

Figure 3 shows the intrusion detection system using a Michelson Interfer-

ometer [20]-[21],[28], consisting of a pulsed laser source, one coupler and twoarms of different optical lengths. The Michelson interferometer produces anddivides the optical pulses to both of the arms. Photo-detector circuitry by doingsuitable signal processing measures and correlates the light reflected back fromboth the arms.

The optical time domain reflectometer (OTDR) injects laser to one end of

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Figure 2: Mach-Zehnder Interferometry[13]-[16], [22]-[23], [26]-[27]

Figure 3: Michelson Interferometry [20]-[21], [28]

a fibre, and measure the reflected Rayleigh back-scattered light using a Photo-detector. The received signals of back-scattered light with respect to timehelp OTDR to identify the disturbances and the damages within the fibre. InPhase-sensitive Optical Time-Domain Reflectometry (-OTDR)[11]-[12],[14]-

[15], phase changes are measured by comparing the fresh signal trace from thesensing fibre with the previous few traces stored in the memory. Also, by usingsingle frequency pulsed laser with a very narrow line-width, localization of thedisturbance in the optical fibre is possible. Figure 5shows the intrusion detec-tion system using an -OTDR. Similarly, Complementary Correlation OpticalTime-Domain Reflectometry (CC-OTDR)[7], [34], correlates the transmitted

light beam with the Rayleigh back-scattered light using a signal processingsystem. Figure6 shows the intrusion detection system using a CC-OTDR.

Brillouin Optical Time Domain Reflectometer (B-OTDR)[8], [35]-[41]workson the measurement of Brillouin frequency shift, which is a built-in parameterof the optical fibre cable. Brillouin frequency shift defines the local information

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Figure 4: Sagnac-Michelson (merged) Interferometry[29]-[30]

Figure 5: Phase-sensitive Optical Time-Domain Reflectometry (-OTDR) [11]-[12], [14]-[15]

of strain and temperature for optical fibre cable. Figure 7 shows the intrusiondetection system using a B-OTDR.

Polarization Optical Time Domain Reflectometer (P-OTDR) [9], [42]-[44] isbased on the measurement of the States of Polarization (SOP) and PolarizationMode Dispersion (PMD) of an optical fibre cable. In an optical fibre polarizationstate changes, with the change in stress level over the fibre cables. P-OTDRconnects to only one end of the optical fibre cable and is very suitable for fieldmeasurements with optical fiber cables. Figure8 shows the intrusion detectionsystem using a P-OTDR.

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Figure 6: Complementary Correlation Optical Time-Domain Reflectometry (CC-

OTDR)[7], [34]

Figure 7: Brillouin Optical Time Domain Reflectometer (B-OTDR) [8], [35]-[41]

Figure 8: Polarization Optical Time Domain Reflectometer (P-OTDR) [9], [42]-[44]

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Configuration, Design and InstrumentationIn this section, the idea, concept and design of a virtual fencing system based ondistributed fibre optic sensing is discussed and presented. As shown in the fig-ure9,a sensing cable connected to a laser source and the photo-detector/imagesensor using a coupler forms an Interferometer. The back-scattered light fromthe fibre cable to the detector holds a signature of the event (stress, groundborne vibrations and rise in temperature) nearby the buried fibre cable sensor, interms of change in wavelength, frequency, phase, intensity etc. Photo-detectoris proposed to be connected with a custom made processing unit based onFPGA or a Digital Signal Processor, making the module capable of performing

signal processing techniques on the reflected back signals, capable of identifyingthe events and finally transmitting the final results to the connected wirelessmodule (in case of positive detection of an event).

For events classification, neural networks are proposed to be implementedon FPGA/DSP based processors. Event signatures could be identified, capturedand stored in database during lab based and in-situ outdoor testing of the sensorsystem. A pre-trained neural network classifier based on the neural networktraining provided on the database of event signatures, is to be implementedon FPGA/DSP based processing unit. The processing unit will be responsiblefor pre-signal processing, implementation of signal processing/event detection

algorithms, classification of events (in case of positive detection) using neuralnetwork classifier and then connecting the results to the wireless module/node.

Figure 9: Design of a Virtual Fencing System based on Distributed Fibre Optic Sensing

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HCTL Open Science and Technology Letters (HCTL Open STL)Edition on Wireless and Wired Networks: Advances and Applications,Volume 3, November 2013, e-ISSN: 2321-6980ISBN (Print): 978-1-62951-015-6 References

Conclusion and Future WorkThe idea, concept and design of a virtual fencing system based on distributedfibre optic sensing for forest and wildlife protection is presented. Initial setupand testing of the design will be first planned in the indoor and then in outdoorenvironment. During the lab and in situ based setup, various Interferometricmethods will be tested and compared to get the clear and detectable signal signa-tures for the events like stress, ground borne vibrations and rise in temperatureover or nearby the buried fibre cable sensor. The design and implementation ofcustom made processing unit based either on FPGA based or a digital signalprocessor, signal processing techniques and algorithm for event detection, neural

network design and algorithm for event classification is pro-posed as a futurework. Interfacing fibre optic based virtual fencing system with the wirelessmodules, setting up and testing the wireless sensor network in indoor andoutdoor environment, designing and development of a deterrent fence for animaldivert-back system and its interfacing with the virtual fencing system is alsoproposed as a future work.

Acknowledgement

This research paper is made possible through the help and support from everyone,including my parents, teachers, family, friends, and in essence, all sentient beings.

Especially, please allow me to dedicate my acknowledgment of gratitude towardProf. M. Radhakrishna (Division of Microelectronics, IIIT-Allahabad, India)and Mr. J. K. Chhabra (Ex-Scientist, CSIO, India) for providing their significantsuggestions and critical reviews in writing this article.

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[45] Raj Gaurav Mishra, Amit Kumar Shrivastava, Implementation of CustomPrecision Floating Point Arithmetic on FPGAs, HCTL Open InternationalJournal of Technology Innovations and Research, Volume 1, January 2013,Pages 10-26, ISSN: 2321-1814, ISBN: 978-1-62776-012-6.

[46] Amit Kumar Shrivastava, Himanshu Joshi, Design, Implementation andFunctional Verification of Serial Communication Protocols (SPI and I2C)

on FPGAs, HCTL Open International Journal of Technology Innovationsand Research, Volume 4, July 2013, Pages 72-81, ISSN: 2321-1814, ISBN:978-1-62776-132-1.

This article is an open access article distributed under the terms and con-ditions of the Creative Commons Attribution 3.0 Unported License (http://creativecommons.org/licenses/by/3.0/ ).

c2013 by the Authors. Sponsored and Licensed by HCTL Open, India.

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Distributed Fibre Optic Virtual Fencing System