JP4748981B2 - Intrusion detection sensor and intrusion detection system - Google Patents

Description

  The present invention relates to an intrusion detection sensor that detects an intrusion into a building or site using an optical fiber detection sensor, and an intrusion detection system using the intrusion detection sensor.

  In recent years, there has been an interest in security against terrorism and illegal intrusions at airports, harbors, defense facilities and other important facilities, and various intrusion detection devices and intrusion detection systems that detect intrusions into buildings and sites have been proposed and implemented. It has also been.

As detection sensors used in this type of apparatus and system, there are known vibration sensors, infrared cut-off sensors, electric field sensors, mechanical tension sensors, and state variation sensors for monitoring images by monitoring monitors. Furthermore, an optical fiber sensor using an optical fiber has been proposed (see, for example, Patent Document 1).
As a monitoring system linked with a detection sensor, there are known a system for recording an image by an ITV camera and a remote monitor, a system for performing image analysis, a system for generating an alarm by an alarm device, and a radio report.

  The detection sensor according to Document 1 detects whether the optical signal emitted from the optical fiber is reflected by the detection target (whether the detection target is at a predetermined position) as the presence or absence of reflected light. For this reason, if a large number of detection points (detection points) are set up in a wide area to be detected and an attempt is made to monitor in a monitoring room, etc., it is necessary to install an optical fiber having a huge number and length from the monitoring room. Become.

  As other detection sensors using an optical fiber, there are an optical fiber detection sensor based on an FBG (fiber Bragg grating) system and an optical fiber detection sensor based on an OTDR (optical time domain reflectometry) system.

  FIG. 7 illustrates in principle an optical fiber type detection sensor based on the FBG method. As shown in the figure, grating portions (FBG) 101 having different refractive indexes of fiber glass are provided at regular intervals in the length direction of the optical fiber 100. The grating unit 101 resonantly reflects only the wavelength component twice the interval λL in the pulsed light incident from the optical pulse generator 102. This reflected light utilizes the fact that the wavelength shifts in proportion to the amount of elongation distortion of the grating unit 101, and this reflected light is derived by the half mirror 103 and further detected by the photodetector 105 through the narrow-band variable filter 104. Thus, it is possible to detect whether or not the elongation distortion amount of the optical fiber exceeds a certain value from the degree of wavelength shift (frequency shift). When this detection is made, the position of the grating unit 101 can be identified as an intrusion location.

  FIG. 8 illustrates in principle an optical fiber type detection sensor based on the OTDR method. An optical fiber has a portion with a different optical refractive index inside, and when the light passes through this portion, the light is refracted and scattered due to the difference in refractive index, and light having the same wavelength as the incident light is reflected to the incident end. Come. The OTDR detection sensor uses this Rayleigh scattered light, enters the optical fiber 107 from the optical pulse generator 106, derives the Rayleigh scattered light by the half mirror 108, receives it by the photodetector 109, and the amount of this light Further, it is possible to detect the distortion and displacement of the optical fiber and the position of the disconnection from the reflection time.

Intrusion detection devices using the above-mentioned FBG optical fiber detection sensor and OTDR optical fiber detection sensor enable intrusion detection by laying along the fence or fence of the site or facility where the optical fiber is to be detected. Become. In particular, in the optical fiber detection sensor based on the FBG method, by incorporating a plurality of FBGs having different reflection wavelengths into the core portion of one optical fiber, simultaneous intrusion detection at a large number of locations becomes possible, compared with the method of Patent Document 1. The required number of optical fibers can be reduced to one-tenth.
JP 2001-296111 A

  As described above, intrusion detection devices and systems that use optical fiber detection sensors based on the FBG method or the OTDR method can detect intrusions at a plurality of locations using a single optical fiber. An optical fiber detection sensor is superior to other detection sensors in terms of EMI resistance, weather resistance, maintenance-free, and the like, and is suitable as a sensor for intrusion detection and monitoring.

  However, as described in detail below, the FBG optical fiber detection sensor is limited to a maximum of a dozen locations that can be detected by a single optical fiber. If a (detection point) is set and monitoring is performed in a monitoring room or the like, a large number of optical fibers must be installed.

  In the FBG type detection sensor, in order to use the wavelength shift of the reflected wavelength from the FBG for intrusion detection, as shown in FIG. 9, grating portions 111A to 111N are incorporated at appropriate intervals in the core portion of the optical fiber 110, and each of these gratings is incorporated. The reflection wavelengths of the portions 111A to 111N are made different from λn, λn + 1, λn + 2, λn + 3,..., And the detection device 112 individually detects the reflected waves of the grating portions 111A to 111N and detects the presence or absence of the wavelength shift. By doing so, the grating portion where the elongation strain is generated is detected, that is, the intrusion portion is detected.

  Here, for example, the photodetector 112 has a relatively narrow 40 nm band of 1528 nm to 1568 nm as a detection band of the reflected wavelength, and discriminates a large number of wavelengths λn, λn + 1, λn + 2, λn + 3,. In order to reliably detect the wavelength shift, only a few dozen channels can be secured.

  In order to increase the number of channels that can be detected, it is conceivable that the pulsed light and reflected light input to the optical fiber have a wide band. However, the FBG requires a large number of different types of wavelengths, and further, an optical fiber and a photodetector. Etc. require a transmission band and a discrimination function of a large number of channels, optical fibers and photodetectors become expensive, and separation detection for each channel may become unstable.

  Similarly, in the OTDR type optical fiber detection sensor, intrusion detection at a large number of locations can be performed with a single optical fiber, but separation detection for each channel becomes unstable when trying to detect multiple points.

  An object of the present invention is to provide an intrusion detection sensor capable of dramatically expanding the position that can be detected using an FBG type detection sensor, and that can detect an intrusion with relatively low cost and high stability. It is to provide a used intrusion detection system.

In order to solve the above-mentioned problems, the present invention, as an intrusion detection sensor using the FBG method, bundles at least two optical fibers incorporating a plurality of FBGs exhibiting a plurality of types of reflection wavelengths, and incorporates them into a single cable. Each FBG that is laid along the range and has the same or different combination of reflection wavelengths of the FBGs at the same position in the length direction of each optical fiber, and detects each FBG having a wavelength shift in the reflected wave with respect to the optical input to each optical fiber Then, an intrusion position is detected from a combination of differences in reflection wavelengths of the FBGs, and an intrusion detection system is constructed using the intrusion detection sensor, and is characterized by the following configuration.

(Invention of intrusion detection sensor)
(1) A plurality of types of FBGs (grating portions) having different refractive indexes of fiber glass are provided at regular intervals in the length direction of the optical fiber, and the optical fiber is laid along a detection target range to respond to light input to the optical fiber. An intrusion detection sensor based on the FBG method for deriving a reflected wave from each FBG and detecting the position of the FBG exhibiting a wavelength shift among the reflected waves as an intrusion location,
A bundle of at least two optical fibers is incorporated into a single cable, and the reflection wavelengths of the FBGs at the same position in the length direction of each optical fiber are the same and different combinations. When detecting each FBG position where a shift has occurred, a detection means for detecting an intrusion position from a combination of differences in reflection wavelengths of the FBG is provided.

(2) The detection means collectively detects a reflected wave from each FBG as an electric signal frequency when an optical input of an optical signal in a band including a reflection wavelength of each FBG is generated, or When an optical input of an optical pulse signal having an individual reflection wavelength of each FBG is generated, it is selectively detected as the frequency of the electrical signal, and the wavelength of each optical fiber shifted by comparing the frequency of each frequency signal with a reference frequency signal. The present invention is characterized in that the position of the FBG is detected as a difference in timing of each pulse output signal, and the intrusion position is determined by the logical sum operation of each pulse output signal.

  (3) The detection means is characterized in that the detection of the reflected wave from each FBG is obtained by a plurality of average value calculations.

(4) The detection means determines an intrusion position by intrusion detection a plurality of times.

(Invention of intrusion detection system)
(5) Bundle at least two optical fibers incorporating multiple FBGs exhibiting multiple types of reflection wavelengths into one cable, lay along the detection target range, and at the same position in the length direction of each optical fiber The reflection wavelengths of the FBGs are the same or different, and each FBG having a wavelength shift in the reflected wave with respect to the optical input to each optical fiber is detected, and the intrusion position is detected from the combination of the differences in the reflection wavelengths of the FBGs. An FBG-type intrusion detection sensor;
An intrusion detection server that is provided on the monitoring room side, acquires an intrusion detection signal from the intrusion detection sensor via a TCP / IP communication interface and a local area LAN, and displays the screen on a monitor;
A monitoring backup facility provided on the monitoring room side with the ITV monitoring system as a central part, and provided with information input / output means for detection and monitoring in cooperation with the intrusion detection sensor, ITV camera, etc. via the local area LAN;
It is provided with.

  (6) The FBG-type intrusion detection sensor has a configuration in which an optical fiber is stretched over the fence provided along the detection target range, and an optical fiber detection sensor of the OTDR system is stretched under the fence. And

  (7) The monitoring backup facility performs communication between the monitoring room and the ITV camera at the monitoring site using the local LAN as an information transmission means, and communication between the inside and outside by an IP phone, a LAN terminal, a wireless LAN satellite, and a wireless LAN terminal. Further, it is characterized by a configuration that enables Internet communication through an IP-BOX in a monitoring room.

(8) The laying structure of the optical fiber along the detection target range is:
A rectangular frame with an appropriate width and height, an optical fiber stretched in a zigzag pattern along the plane formed by this frame, and both ends of the optical fiber are optically connected to both sides of the frame. A fence unit composed of an optical connection box
Among the fence units arranged along the detection target range, an optical connection cord that connects between the optical connection boxes of adjacent fence units, and
It is characterized by comprising a connecting box at the beginning or the end of the optically connected fence unit array and an optical fiber connecting the light input / output means for inputting / outputting light to / from the optical fiber.

(9) The at least two optical fibers are bundled and incorporated into one cable, and a synthetic resin or metal piercing member is attached or penetrated at an appropriate interval along the longitudinal direction of the incorporated optical fiber cable. A barbed wire is formed, and this barbed wire is stretched along a fence.

As described above, according to the intrusion detection sensor of the present invention, at least two optical fibers incorporating a plurality of FBGs exhibiting a plurality of types of reflection wavelengths are bundled and assembled into a single cable and laid along a detection target range. In addition, the reflection wavelength of each FBG at the same position in the length direction of each optical fiber has the same or different combination, and each FBG in which a wavelength shift occurs in the reflected wave with respect to the optical input to each optical fiber is detected, and the reflection of the FBG is detected. Since the intrusion position is detected from a combination of different wavelengths, the detectable position can be greatly expanded, and intrusion detection can be performed with relatively low cost and high stability.

  In addition, by constructing an intrusion detection system using the intrusion detection sensor according to the present invention, the required number of installed optical fibers can be significantly reduced even when a wide detection range is required such as airports, harbors, and defense facilities. It is possible to reduce the cost of system construction and improve reliability.

  Further, since the optical fiber laying structure is the fence unit arrangement method, the construction period of system construction can be shortened.

  In addition, since a barbed wire is constructed by attaching or penetrating a synthetic resin or metal piercing member at an appropriate interval along the longitudinal direction of an optical fiber cable incorporating at least two optical fibers, A fence structure in which both functions of intrusion detection are integrated can be obtained.

(Embodiment 1)
FIG. 1 is a configuration diagram of an intrusion detection sensor showing an embodiment of the present invention. The two optical fibers 10A and 10B are incorporated with a plurality of types of FBGs that obtain reflected waves of different wavelengths, and are bundled into a single cable, or are processed so as to be integrated into a single unit. Etc. are laid along the intrusion detection target route.

  The optical signal generator 11 continuously or intermittently (pulse-like) generates an optical signal in a band that includes the reflection wavelength of each FBG incorporated in the optical fibers 10A and 10B. The half mirrors 12A and 12B use the optical signals from the optical signal generator 11 as optical inputs to the optical fibers 10A and 10B, respectively, and the reflected lights from the FBGs of the optical fibers 10A and 10B to the narrow-band variable filters 13A and 13B, respectively. Deriving light. The narrow-band variable filters 13A and 13B collectively transmit the reflected waves from the FBGs and output the reflected waves to the photodetectors 14A and 14B, respectively. The photodetectors 14A and 14B collectively convert the optical inputs transmitted through the filters 13A and 13B into electric signals having the same frequency as the optical inputs.

  The wavelength shift detectors 15A and 15B perform frequency comparison between the frequency signal obtained by the photodetectors 14A and 14B and the reference frequency signal from the reference frequency generator 16, and a pulse having a timing for each reflected wavelength at which the frequency shift has occurred. Signals (hereinafter referred to as λa and λb) are obtained. The OR operation unit 17 obtains a pulse signal (λa OR λb) obtained by taking the logical sum of both pulse signals λa and λb. The intrusion position determination unit 18 determines the position of the FBG whose reflection wavelength is shifted based on the pulse signal (λa OR λb), that is, the intrusion position, and obtains its output.

  The operation of the intrusion detection sensor configured as above will be described. First, as shown in the example of FIG. 1, the two optical fibers 10A and 10B are assumed to incorporate FBGs each having eight kinds of reflection wavelengths λ1 to λ8 in ascending order (or descending order or random order). However, the installation positions of the FBGs are changed so that the reflection wavelengths of the FBGs at the same positions of the optical fibers 10A and 10B have different combinations. For example, in FIG. 1, at the position P1 in the longitudinal direction of the optical fiber, one FBG has a reflection wavelength λ1, and the other has a reflection wavelength λ1. At the position P9, one FBG has a reflection wavelength λ1, and the other has a reflection wavelength λ2.

  The combination in which the reflection wavelengths of the FBGs at the same position are different from each other is 8 × 8 = 64 when 8 types of FBGs are incorporated in both optical fibers 10A and 10B. In the general formula, the combination of FBGs having N kinds of reflection wavelengths is expanded to “the square of the number of kinds N” at the maximum.

  As shown in FIG. 2, an optical signal having a band including wavelengths λ1 to λ8 is incident on the pair of optical fibers 10A and 10B having such a structure as shown in FIG. As a result, the reflected waves from the optical fibers 10A and 10B have wavelengths λ1 to λ8, respectively, and the reflected waves are led out to the filters 13A and 13B via the half mirrors 12A and 12B, respectively. The wavelengths are detected by the photodetectors 14A and 14B. It is converted into a signal having frequencies f1 to f8 corresponding to λ1 to λ8.

  Since a plurality of FBGs having the same reflection wavelength are incorporated in the same optical fiber, reflected waves from the same FBG are slightly shifted in time due to the difference in the position of the FBG on the optical fiber. Then, it can derive | lead-out as the same reflected wave superimposed.

  The reference frequency generator 16 collectively generates a reference frequency signal having the same narrow band as the frequency signals having these frequencies f1 to f8, and the wavelength shift detectors 15A and 15B include the reference frequency signal and the photodetectors 14A and 14A, respectively. The frequency comparison with the frequency signal is performed at 14B, and if there is a frequency signal in which a frequency shift has occurred, it is output in association with the timing of the output pulse. In the example of FIG. 2, a wavelength shift occurs at the wavelength λ5 of the reflected wave of the optical fiber 10A, and a wavelength shift occurs at the wavelength λ4 of the reflected wave of the optical fiber 10B.

  A logical sum operation is performed on the outputs λa and λb of these wavelength shift detectors 15A and 15B by the logical sum operation unit 17 to obtain a pulse signal (λa OR λb) having a timing corresponding to a combination of wavelength shifted FBGs. The intrusion position determination unit 18 can obtain an intrusion position determination output by converting the timing of λa and λb into a decimal number corresponding to the binary digit position.

  Therefore, according to the intrusion detection sensor according to the present embodiment, both optical fibers 10A and 10B are used in which the intrusion positions that can be detected independently are limited to N places, and at many places where N squares. Intrusion detection, that is, the number of channels can be dramatically expanded, and the number of optical fibers that need to be laid can be greatly reduced even when there are many detection points (detection points). In addition, the optical signal input to the optical fiber and the signal processing of the reflected light only need to be able to separate and extract N types of wavelengths equivalent to the conventional one, and the optical fiber and the photodetector do not become expensive and stable intrusion. Can be detected.

  Although this embodiment shows a case where a sensor configuration using two optical fibers is used, in order to further increase the number of channels, if three or more optical fibers and their signal processing circuits are used, the FBG is used. It is possible to realize a multi-point detection sensor having the number N of the number N of 3 or more.

  Moreover, although this embodiment shows the structure which performs wavelength shift determination collectively with respect to reflection wavelength (lambda) 1- (lambda) 8, it can also determine in a time division manner. In this case, the optical signal generator 11 generates optical pulses having individual reflection wavelengths instead of generating optical signals in a band including the reflection wavelengths of the FBGs incorporated in the optical fibers 10A and 10B. The filters 13A and 13B and the photodetectors 14A and 14B sequentially extract the frequency signals of the reflected wavelengths for the individual wavelengths, and sequentially detect the wavelength shifted signals by the wavelength shift detectors 15A and 15B.

  Further, when the signal is converted by the photodetectors 14A and 14B, if the signal is converted into a low frequency band obtained by multiplying the frequency by 1 / n, the signal processing circuit in the subsequent stage has a simple processing function at a low frequency. That's it. Furthermore, the detection of the reflected wave signal by the light receiving units 14A and 14B is performed when the average value obtained by a plurality of times of light reception is obtained, and the optical fiber causes frequency fluctuations or fluctuations in the reflected wavelength due to changes in installation environment (wind or temperature). In addition, the reliability of intrusion detection can be improved. Similarly, the determination by the intrusion position determination unit 18 is not limited to the configuration in which the intrusion detection is determined when the wavelength shift occurs once, but the intrusion detection reliability is obtained by obtaining a final determination by a plurality of intrusion detections. It can also improve sex.

  In addition, the configuration of each part from detection of the reflected wave to determination of the reflected wave having the wavelength shift can be appropriately changed in design.

(Embodiment 2)
FIG. 3 is an overall configuration diagram of an intrusion detection system showing an embodiment of the present invention, which detects an intruder trying to get over the fence installed on the outer periphery of the site and further detects an intruder trying to destroy the fence System.

  An optical fiber cable 21 for an optical fiber type detection sensor based on the FBG method is laid on the fence 20. This optical fiber cable 21 incorporates at least two optical fibers each incorporating a plurality of types of FBGs having different reflection wavelengths, thereby realizing the light detection sensor system in the first embodiment.

The optical fiber 22 for the optical fiber detection sensor based on the OTDR method is laid on the fence 20 from the height position of the optical fiber cable 21 to the ground portion. In the OTDR method, as described above, since a plurality of locations cannot be detected simultaneously, an optical fiber is laid for each intrusion detection area.
Each of the optical fibers 21 and 22 is bundled as one or a plurality of optical fiber cables, and is also used as an optical transmission path that leads to the optical patch panel 23. Here, the optical patch panel 23 is an optical cable terminal board for connecting the optical fiber cable laid on the exterior and the local optical cable.

  The FBG intrusion detector 24 is connected to the optical fiber 21 and includes detection elements from the FBG optical signal generator 11 to the intrusion position determination unit 18 in the first embodiment to obtain an intrusion position determination output signal. The intrusion detector 25 is connected to the optical fiber 22 and obtains an intrusion position determination output signal by the OTDR method.

  The TCP / IP communication interface 26 is connected to the intrusion detectors 24 and 25 via the communication cable 27 and performs input / output signal processing when an intrusion detection determination output is obtained in each of the intrusion detectors 24 and 25. .

  The intrusion monitoring server 28 provided in the monitoring room enables information transmission to and from the TCP / IP communication interface 26 via the local area LAN, and intrusion detection information by TCP / IP communication with the intrusion detectors 24 and 25. When the intrusion detection information is acquired, screen display on the monitor 29, that is, screen display processing for allowing the observer to recognize the intrusion position is performed.

  The monitoring backup facility 30 provided in the monitoring room has an ITV monitoring system as a central part, and information input / output means for detection and monitoring in cooperation with FBG and OTDR intrusion detection sensors and ITV cameras via a local area LAN. Is provided.

  For example, in the ITV monitoring system, the detection signals (including the intrusion position signal) of the detectors 24 and 25 are fetched as interrupt signals through the TCP / IP communication interface 26, and further the monitoring video signal from the ITV camera installed in the monitoring area is received. Received through the local area LAN and displays alarms and their images on multiple ITV monitors.

  At this time, in parallel with the notification of the intrusion, an optimal image is previously displayed on the monitor for each detection position in order to identify the intrusion. As a result, the monitor can be provided with image information for making an accurate judgment on intrusion. Also, by including detection position information in the intrusion detection signal, the shooting direction of the ITV camera is automatically directed to the detection position, and the subsequent moving object tracking control (identification of moving objects and detection of movement direction by image analysis is performed. Therefore, even if the intruder moves from the detection position, the image is not deviated from the image on the ITV monitor.

  In addition, the ITV monitoring system takes in an operation signal generated by an operation of a joystick or the like on the ITV operation panel and controls the ITV camera (shooting direction, zoom, etc.) in accordance with this signal, so Enables manual operation of the ITV camera, and enables more accurate monitor image acquisition.

  Furthermore, the monitoring backup facility 30 enables communication between the monitoring room and the ITV camera at the monitoring site using the local LAN as an information transmission means, and communication between the inside and outside by the IP phone, the LAN terminal, the wireless LAN satellite, and the wireless LAN terminal. Furthermore, it enables Internet communication through the IP-BOX in the monitoring room.

  Among these, IP telephones are connected to a connection port installed near the route of the monitoring area with a VoIP telephone using a modular cord, and it is possible to call not only the monitoring room but also the monitoring center and system design company for patrol monitoring. It also enables specialist engineers to support system maintenance work. Similarly, a LAN terminal has a built-in LAN (TCP / IP) and is connected to an IP telephone connection port, thereby enabling transmission and reception of information from the location to a monitoring center, a security company, or the like. The wireless LAN terminal can transmit and receive information via a wireless LAN satellite installed near the route of the monitoring area, and is used for transmission and reception of maintenance information, monitoring information, and measurement information attached to the original operation of the intrusion detection system.

  In the present embodiment, the optical fiber 22 may be of the FBG system instead of the OTDR system, and the photodetector may be changed for that. In this case, the number of optical fibers 22 can be greatly reduced.

(Embodiment 3)
FIG. 4 shows an example of a fence structure in the intrusion detection system or the like according to the second embodiment. The fence unit 40 includes a rectangular frame 41 having an appropriate width and height, an optical fiber 42 stretched zigzag (staggered) along a plane formed by the frame 41, and both sides of the frame 41. It is comprised by the optical connection box 43 which optically connects the both ends of the optical fiber 42 with a frame.

  The fence unit 40 having this configuration is assembled in advance at the factory, transports the necessary number to the site to be intrusion detection, and these are attached and fixed along the fence base of the site. Then, the optical connection cords 44 are optically connected between the optical connection boxes 43 of the adjacent fence units 40. Further, the connection box at the head or tail of the array fence unit 40 and the optical input / output device that inputs / outputs light to / from the optical fiber 42 are connected by an optical fiber.

  Therefore, according to the fence structure according to the present embodiment, the fence unit 40 can be assembled at the factory, and the construction period can be shortened and the cost can be reduced as compared with the case where the entire structure is manufactured locally. In particular, it facilitates optical fiber installation work and operation check, and is effective in improving reliability.

  FIG. 5 shows a modification example of the connection between the fence units. In order to separate and configure the plurality of warning areas A and B, the connection path of the optical connection cord 44 that optically connects the fence units 40 is changed. Just do it.

(Embodiment 4)
FIG. 6 shows an example of the structure of an optical fiber cable in the first to third embodiments. In this structure, a synthetic resin or metal piercing member 51 is attached or penetrated at an appropriate interval along the longitudinal direction of the optical fiber cable 50 to form a barbed wire, and the barbed wire runs along the fence. To stretch.

  Therefore, according to the optical fiber cable structure according to the present embodiment, a cable having a barbed wire function can be realized. In particular, when applied to the fence unit shown in Embodiment 3, it is possible to obtain an excellent effect that the optical fiber cable and the barbed wire can be stretched together.

  Each of the embodiments described above shows an intrusion detection sensor that detects an intruder trying to get over the fence installed on the site, and further detects an intruder trying to destroy the fence. Established a sensor and system that detects the intrusion or destruction of humans and animals (small animals such as mice) through manholes for sewage channels and power / communication cable pits, and added a detection function. A system can be constructed.

The block diagram of the intrusion detection sensor which shows embodiment of this invention. Operation | movement explanatory drawing of the intrusion detection sensor in FIG. The block diagram of the intrusion detection system which shows embodiment of this invention. The block diagram which shows embodiment of the fence in FIG. The block diagram which shows the modification of the fence in FIG. The block diagram of the optical fiber cable which shows embodiment of this invention. The principle explanatory drawing of the detection sensor of a FBG system. FIG. 3 is a diagram illustrating the principle of an OTDR detection sensor. Explanatory drawing of the wavelength and intrusion position detection relationship in a FBG system.

Explanation of symbols

10A, 10B Optical fiber 11 Optical signal generator 12A, 12B Half mirror 13A, 13B Narrow band variable filter 14A, 14B Photo detector 15A, 15B Wavelength shift detector 16 Reference frequency generator 17 OR operation section 18 Intrusion position determination section 20 Fence 21 Optical fiber cable (FBG method)
22 Optical fiber cable (OTDR system)
DESCRIPTION OF SYMBOLS 23 Optical patch panel 24, 25 Intrusion detector 26 TCP / IP communication interface 27 Communication cable 28 Intrusion monitoring server 29 Monitor 30 Monitoring backup equipment 40 Fence unit 41 Frame 42 Optical fiber 43 Optical connection box 50 Optical fiber cable 51 Stitch member

Claims (9)

A plurality of types of FBGs (grating portions) having different refractive indexes of fiber glass are provided at regular intervals in the length direction of the optical fiber, and the optical fiber is laid along a detection target range. An intrusion detection sensor based on the FBG method that derives a reflected wave from the FBG and detects the position of the FBG that exhibits a wavelength shift in the reflected wave as an intrusion location,
At least two of the optical fibers are bundled into one cable, and the reflection wavelengths of the FBGs at the same position in the length direction of the optical fibers are the same and different combinations, so that the reflected waves corresponding to the light input to the optical fibers are reflected. An intrusion detection sensor provided with a detecting means for detecting an intrusion position from a combination of differences in reflection wavelengths of FBGs when detecting each FBG position where a wavelength shift has occurred. The detection means collectively detects the reflected wave from each FBG as the frequency of the electric signal when an optical input of an optical signal in a band including the reflection wavelength of each FBG is generated, or each FBG When optical input of optical pulse signals with individual reflection wavelengths occurs, it is selectively detected as the frequency of the electrical signal,
The configuration is such that the position of the FBG of each optical fiber shifted in wavelength by comparing the frequency of each frequency signal and the reference frequency signal is detected as a difference in timing of each pulse output signal, and the intrusion position is determined by OR operation of each pulse output signal. The intrusion detection sensor according to claim 1.   The intrusion detection sensor according to claim 1, wherein the detection unit is configured to obtain a detection of a reflected wave from each FBG by a plurality of average value calculations.   The intrusion detection sensor according to claim 1, wherein the detection unit determines an intrusion position by detecting intrusion a plurality of times. At least two optical fibers incorporating a plurality of FBGs exhibiting a plurality of types of reflection wavelengths are bundled into one cable, laid along the detection target range, and each FBG at the same position in the length direction of each optical fiber Of the FBG method that detects the intrusion position from the combination of the difference in the reflection wavelength of the FBG, detecting each FBG in which the wavelength shift occurs in the reflected wave with respect to the light input to each optical fiber. An intrusion detection sensor,
An intrusion detection server that is provided on the monitoring room side, acquires an intrusion detection signal from the intrusion detection sensor via a TCP / IP communication interface and a local area LAN, and displays the screen on a monitor;
A monitoring backup facility provided on the monitoring room side with the ITV monitoring system as a central part, and provided with information input / output means for detection and monitoring in cooperation with the intrusion detection sensor, ITV camera, etc. via the local area LAN;
An intrusion detection system characterized by comprising:   The FBG intrusion detection sensor has a configuration in which an optical fiber is stretched on an upper portion of a fence provided along a detection target range, and an optical fiber of an OTDR optical fiber detection sensor is stretched on a lower portion of the fence. Item 6. The intrusion detection system according to Item 5.   The monitoring backup facility enables communication between the monitoring room and the ITV camera at the monitoring site using the local LAN as an information transmission means, and communication between the inside and outside by an IP phone, a LAN terminal, a wireless LAN satellite, and a wireless LAN terminal, The intrusion detection system according to claim 5 or 6, further comprising an internet communication through an IP-BOX in a monitoring room. The laying structure of the optical fiber along the detection target range is:
A rectangular frame with an appropriate width and height, an optical fiber stretched in a zigzag pattern along the plane formed by this frame, and both ends of the optical fiber are optically connected to both sides of the frame. A fence unit composed of an optical connection box
Among the fence units arranged along the detection target range, an optical connection cord that connects between the optical connection boxes of adjacent fence units, and
8. The optical fiber connecting between the first or last connection box of the optically connected fence unit array and an optical input / output means for inputting / outputting light to / from the optical fiber. The intrusion detection system according to any one of the above. The at least two optical fibers are bundled and incorporated into a single cable, and a synthetic resin or metal piercing member is attached or penetrated at an appropriate interval along the longitudinal direction of the incorporated optical fiber cable. The intrusion detection system according to any one of claims 5 to 8, wherein the barbed wire is stretched along a fence.

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