JP2005345137A - Intruder detection device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an intruder detection device equipped with a structure hardly recognized to be a detector by the intruder, while protecting an optical fiber from external noise vibration, and reducing the capability of erroneous detection. <P>SOLUTION: In the intruder detection device of a fiber ring interference type, a pipe is laid along the direction of a fence, and the optical fiber is arranged by being inserted. Consequently, the optical fiber is protected from erroneous vibrations caused by rain, wind or the erroneous vibration caused by collision of a bird etc., and the erroneous detection accompanied by these erroneous vibrations, and also by inserting the optical fiber into the pipe, the intruder can be made to hardly recognize the detector (optical fiber). <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to an intruder detection apparatus that detects an intruder who has entered a fence or fence, and more particularly to an intruder detection apparatus using an optical fiber ring interference sensor.

As shown in FIG. 7, as a conventional system for detecting illegal intrusion around a harbor quay and management facility, a fence 103 is stretched around the management area, and a detection wire 105 is stretched around the beam above the fence 103. There is an intruder detection device in which a monitoring ITV (Industrial TeleVision) camera 107 is installed at a main monitoring point of the fence 103 and an interlock device 109 is provided at an entrance.
The monitoring ITV camera 107 is further provided with a wireless transceiver (not shown), a power supply panel 113 and a power cable 111 for supplying power thereto, from a monitoring center provided inside or outside the management area. The monitoring video transmitted from the monitoring ITV camera 107 by remote control can be monitored in real time via a monitoring device (for example, a personal computer) 115.

  According to the intruder detection device 101, when an intruder enters the fence 103 from the outside, the images captured by the monitoring ITV camera 107 are sequentially monitored and detected at the monitoring center, and when the intruder enters. When the detection wire 105 is accidentally cut, the monitoring center is automatically notified to the center by an intruder detection alarm.

  Considering that such an intruder detection device 101 is applied particularly to a harbor or its management facility, its management area is vast and it is a reality to always visually check the monitoring device in combination with complicated management work. However, it is expected that it is difficult to perform monitoring that covers all of daytime and nighttime with the monitoring ITV camera 107 and the locking system.

  Further, the detection wire 105 is liable to cause a power supply abnormality due to lightning and the like, and an intruder cannot be detected unless the detection wire 105 is cut. Furthermore, it is necessary to replace the wire for each detection, and management is complicated.

Therefore, an intruder detection device using an optical fiber ring interference type sensor has been proposed (Patent Document 1, Patent Document 2, Non-Patent Document 1). This intruder detection device detects a wide range of intruders by applying a long optical fiber, and avoids the effects of lightning by using an optical fiber. Further, since the presence / absence of an intruder can be detected by the variation in the optical path length generated when the intruder touches the optical fiber, there is an advantage that the wire can be detected without cutting.
Japanese Patent No. 3357623 Japanese Patent Application No. 2003-200428 Takeshi Tokura, 3 others, “Identification of vibration position by optical fiber ring interference type vibration sensor”, Fujikura Technical Report, Fujikura Co., Ltd., October 2002, No. 103, p. 18-21

  By the way, the above-described optical fiber ring interference type sensors described in Patent Document 1, Patent Document 2, and Non-Patent Document 1 install a part of an optical fiber cable laid in a ring shape on a beam such as a fence or a fence. However, when the optical fiber cable is directly fixed to the fence, the following problems arise.

  First, as a first problem, when vibration due to wind, rain, or the like is transmitted to the optical fiber cable, an optical path length that has fluctuated due to this vibration is detected, which may cause erroneous detection.

  As a second problem, there is a possibility of erroneous detection because the optical path length fluctuates in the same manner as described above when a bird or the like grabs or collides with the optical fiber.

  Further, as a third problem, since the optical fiber cable is directly laid, it can be easily found by an intruder, and there is a possibility that the intruder may enter while avoiding the sensor.

  The present invention has been made in view of the above problems, and its purpose is to protect the optical fiber cable from external noise vibration, reduce the possibility of erroneous detection, and it is difficult to recognize that the intruder is a sensor. It is providing the intruder detection apparatus provided with a structure.

  A second object of the present invention is to provide an intruder detection device that detects an intrusion of a vehicle or the like in a place without a fence such as an entrance / exit as well as an intrusion from a fence or fence.

  In order to achieve the above object, an intruder detection device according to claim 1 is characterized in that an optical branch coupling element is connected to an end of a loop-shaped optical fiber laid so as to surround a monitoring area, After the light emitted from the light source is incident on the end and propagates clockwise and counterclockwise in the optical fiber, it is added onto the optical fiber due to the difference in the optical path length with time. An intruder detection device comprising an optical fiber ring interference type sensor for calculating an excitation point, wherein the optical fiber is laid along the upper or lower beam of the fence surrounding the surveillance area, and the optical fiber The gist is that all or part of the tube is housed in a cylindrical tube.

  The intruder detection device according to claim 2 is the intruder detection device according to claim 1, wherein a trench is excavated along the laying direction of the fence in the ground where the fence is installed, and the fence is supported. The gist is that a vibration transmitting metal fitting for physically connecting the column and the pipe installed in the groove is provided, and the pipe is buried in the ground so that it cannot be identified from the outside.

  The intruder detection device according to claim 3 is the intruder detection device according to claim 1 or 2, wherein a groove formed in the ground of the monitoring area is divided by a movable partition plate, and an optical fiber is provided in one groove. Is placed in contact with this partition plate, and the other groove is filled with a brittle material that converts low-frequency vibrations into high-frequency vibrations, and this groove is sealed and buried in the ground so that it cannot be identified from the outside. It is a summary.

  The intruder detection device according to claim 4 is the intruder detection device according to any one of claims 1 to 3, wherein the optical fiber ring interference type sensor is a loop-shaped optical path formed using an optical fiber. An optical fiber ring interference that obtains a phase difference between the interference lights of the first and second optical signals having different wavelengths from each other using a fiber ring part including the optical fiber ring part and identifies an excitation point generated on the optical fiber ring part The main point is that it is a type sensor.

  According to the present invention, in an intruder detection device using an optical fiber ring interference type sensor, a pipe is laid along the installation direction of a fence, and an optical fiber cable is inserted and disposed therein. This makes it possible to prevent erroneous vibrations due to the occurrence of vibrations, erroneous vibrations caused by the collision of birds and the like, and erroneous detection associated therewith. Further, by inserting and arranging the optical fiber cable in the tube, it is possible to make it difficult for an intruder to recognize the presence of the sensor (optical fiber cable).

  According to the present invention, a duct is provided in the ground below the fence, and an optical fiber cable is accommodated in the duct so that, similarly to the above effect, erroneous vibrations due to rain, wind, etc., and birds collide. It is possible to prevent erroneous vibrations caused by and erroneous detection associated therewith. Further, by inserting and arranging the optical fiber cable in the tube, it is possible to make it difficult for an intruder to recognize the presence of the sensor (optical fiber cable).

  Further, according to the present invention, in order to detect an intruding vehicle, a groove is opened in the ground near the entrance and is divided into two by a movable partition plate, and low-frequency vibration is generated in one groove. Filling the other groove with a brittle material as a material to convert to high-frequency vibration, and attaching an optical fiber cable so as to contact the partition plate, it converts low-frequency vibration caused by the passage of a low-speed vehicle into high-frequency vibration, This vibration can be detected by the fiber cable. As a result, it is possible to detect the intrusion of a vehicle or the like in a place without a fence such as an entrance / exit.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

  1A to 1E are diagrams showing the configuration of the intruder detection device 1. Here, FIG. 1A is an overall configuration diagram of the intruder detection apparatus 1, and FIG. 1B is a cross-sectional configuration diagram of FIG. FIGS. 2C to 2E are diagrams showing other laying examples of the optical fiber cable.

  As shown in FIG. 1A, the intruder detection device 1 includes a support column 11 erected at predetermined intervals on a management area, a fence 3 stretched between the support columns 11, and an upper part of the fence 3. At least a long tube 7 fixed to the beam, an optical fiber cable 5 inserted in the tube 7, and an optical fiber ring interference sensor 13 connected to the end of the optical fiber cable 5 are provided. I have.

  One of the features of the intruder detection device 1 is that the whole or a part of the optical fiber cable connected to the optical fiber ring interference type sensor 13 is inserted into the cylindrical tube 7.

  Here, the pipe 7 installed along the beam of the fence 3 is a cylindrical pipe made of metal, ceramic, resin, or the like. The tube 7 is fixed to the beam of the fence 3 with a fixing bracket 9. The color of the tube 7 is preferably the same color as the fence 3.

  As the optical fiber ring interference sensor 13, the optical fiber ring interference sensor described in Patent Document 1 or Non-Patent Document 1 is used. That is, the optical fiber ring interference type sensor includes at least a light emitting element (for example, a laser diode), a light receiving element (for example, a photodiode), an optical branching and coupling element (for example, an optical coupler), and a loop-shaped optical fiber cable. Is.

  The propagating light emitted from the light source is branched into the light propagating clockwise in the optical fiber and the light propagating counterclockwise and goes around the optical fiber loop, and each light is combined again by the optical branching coupling element. The interference light is detected by the light receiving element. At this time, in a static state where no vibration or impact is applied, the optical path length in the optical fiber ring for clockwise light and counterclockwise light is the same, so the phase difference between them is constant, The signal detected by the element is constant.

  On the other hand, when vibration is applied to the optical fiber ring, a change in refractive index occurs in the optical fiber. At this time, in the light receiving element, this phenomenon is detected as a change in intensity of the interference light of the clockwise light and the counterclockwise light phase-modulated by vibration.

  The optical fiber ring interference sensor 13 having the above-described principle can detect the intruder's intrusion by detecting the change in the optical path length changed by the vibration generated when the intruder gets over the fence 3. At this time, the optical fiber cable which is a sensor part of the optical fiber ring interference type sensor 13 is accommodated in a tube 7 made of a hard material that is not easily bent by human force. There is no false detection of an intruder. Accordingly, erroneous detection can be significantly reduced as compared with an intruder detection device to which a conventional optical fiber cable is applied.

  In addition, as another example of laying shown in FIGS. 1B to 1E, a method of installing the pipe 7 along the beam of the fence 3 as shown in FIG. 1B, or FIG. As shown in Fig. 1 (d), a method of inserting and arranging in the gap inside the beam as shown in Fig. 1 (d), and further providing a protruding plate on the beam as shown in Fig. 1 (e). The method of mounting on a protruding plate is mentioned.

  Here, when the optical fiber cable is inserted and arranged in the gap inside the beam shown in FIG. 1D, the optical fiber cable may be directly inserted and arranged in the gap without providing the pipe 7. Thereby, the cost of the pipe | tube 7 can be reduced.

  As described above, according to the intruder detection device 1 of the present invention, since the optical fiber cable 5 is inserted into the tube 7, vibrations from external noise such as rain, wind, birds, etc. Transmission to the cable can be suppressed.

  Further, since the optical fiber cable 5 is accommodated in the tube 7, it is difficult to recognize the presence of the optical fiber from the outside, and it is difficult for an intruder to notice that the optical fiber ring interference sensor 13 is installed.

  Furthermore, by making the color of the tube 7 and the fence 3 the same color, it is possible to make it difficult to recognize the presence of the optical fiber from the outside, so that it can be made even more difficult for the intruder to notice.

  Next, an intruder detection device 21 according to a second embodiment of the present invention will be described. 2A to 2D are diagrams showing the configuration of the intruder detection device 21. FIG. Here, FIG. 2A is an overall configuration diagram of the intruder detection device 21, and FIG. 2B is a cross-sectional configuration diagram of FIG. FIGS. 2C and 2D are diagrams showing other examples of laying optical fiber cables. In the following description of the present embodiment, the same components as those in the first embodiment are denoted by the same reference numerals, and the description thereof is omitted.

  As shown in FIG. 2 (a), the intruder detection device 21 replaces the installation position of the pipe 7 with the upper part of the fence 3 in the first embodiment, and replaces the lower part of the fence 3. This is different from the first embodiment in that it is fixed to.

  Here, as shown in FIG. 2B, the pipe 7 installed under the beam of the fence 3 is buried in the ground below the fence 3.

  Here, in the laying method shown in FIG. 2B, a groove is dug in the ground along the installation direction of the fence 3, and the duct 19 is first laid in the groove. Then, the impact propagation support bracket 17 is fixed to the support column 11 of the fence 3 and one end thereof is inserted into the duct 19. The end of the inserted support fitting 17 is arranged so as to contact the surface of the tube 7, and the vibration of the fence 3 is always transmitted directly to the tube 7.

  Next, the pipe 7 is accommodated in the duct 19, and the optical fiber cable 5 is inserted through the pipe 7. The duct 19 containing these parts is sealed with a lid 23 and camouflaged with soil or the like so that the lid is not recognized from the outside.

  The installation method of the impact propagation support bracket 17 is not limited to the above-described form, and a second impact propagation support bracket 27 is further provided at one end of the support bracket 17, and the second support bracket 27 and the pipe 7 are directly connected. You may make it contact. Thereby, when the fence 3 is shaken, the vibration is propagated to the pipe 7 through the second support fitting 27.

  The position where the duct 19 is buried need not be directly below the fence 3, but is provided at a position at least far enough to physically propagate the vibration generated in the fence 3 to the optical fiber cable 5. Just do it.

  According to the above configuration, by burying the optical fiber cable in the ground, the presence of the optical fiber sensor can be hardly known from the outside. In order to transmit vibration to the buried optical fiber cable 5, a shock-propagating support bracket 17 fixed to the fence 3 is inserted into the duct 19, and a part of the support bracket 17 is inserted into the duct 19. Therefore, the vibration of the fence 3 can be reliably transmitted to the tube 7 and the optical fiber cable 5 via the support fitting 17.

  On the other hand, the laying method shown in FIG. 2C is a method of bringing the tube 7 into contact with the support 11 directly or indirectly. In the illustrated configuration, a support fitting 25 is provided between the column 11 and the pipe 7, and the pipe 7 is laid along the beam at the lower part of the fence 3 via the support fitting 25. Although not shown, a predetermined position of the pipe 7 is fixed to the fence 3 with a fixing bracket. In FIG. 2C, the pipe 7 is laid on the fence 3 via the support fitting 25, but the present invention is not limited to this, and the pipe 7 may be directly fixed to the beam.

  Further, the laying method shown in FIG. 2D is a method in which an optical fiber cable is inserted and disposed in the gap inside the beam below the fence 3. The optical fiber cable 5 does not necessarily have to be inserted into the tube 7 and may be directly inserted into the gap. Thereby, the cost of the pipe | tube 7 can be reduced.

  On the other hand, when the tube 7 is provided, an effect that the optical fiber can be protected from moisture and corrosion of the outside air can be obtained.

  Therefore, with the above-described configuration, the same effect as that of the first embodiment can be obtained in which erroneous detection can be suppressed by protecting the optical fiber cable 5 from external noise such as rain, wind, and birds. In addition, as a feature of the second embodiment, by embedding an optical fiber cable in the ground, the degree of recognition from the outside can be reduced more effectively than in the case of the first embodiment. The effect of making it difficult for the intruder to recognize the presence of the sensor can be obtained.

  Next, an intruder detection device 31 according to a third embodiment of the present invention will be described. FIG. 3A is a diagram showing a configuration of the intruder detection device 31, and FIG. 3B is an enlarged view of a portion C shown in FIG. The intruder detection device 31 is an intruder detection device that is mainly installed under an entrance / exit passage such as a gate.

  In the first and second embodiments, the vibration of the fence 3 is detected and notified to the administrator. However, even if this is embedded as it is under the entrance / exit passage, the same effect as the above embodiment is achieved. , Can not get the effect. Generally, when a vehicle or the like passes at a low speed, even if a part of the optical fiber cable is laid in the ground, the transmitted vibration becomes low frequency because the passing speed of the vehicle is low, usually several tens of Hz. This is because the optical fiber ring interference type sensor having a band of has low sensitivity and cannot be detected.

  Therefore, as shown in FIGS. 3A and 3B, the intruder detection device 31 excavates a groove below the passage through which the vehicle passes, and vertically arranges a movable partition plate 37 in the groove. The groove is divided into two, and one of the two spaces formed by the partition plate 37 is filled with the granular material 35, and the other space is connected to the optical fiber cable 5 so as to be in contact with the partition plate 37. Deploy.

  Then, a lid 39 is disposed on the groove filled with the granular material 35, and camouflaging is performed by placing soil or gravel on the lid 39. The other groove is sealed so that dust and dirt do not enter and camouflaged from above.

  Here, a protrusion may be provided on the lid 39 in order to press the granular material 35 efficiently. The protrusion shape may be a protrusion having a rectangular cross section as shown in the figure, or a sharp protrusion. The number of protrusions is not limited to one, and a plurality of protrusions may be provided.

  Although not shown, the end of the optical fiber cable 5 is connected to the optical fiber ring interference sensor 13 described in the above embodiment.

  Here, all or part of the optical fiber cable 5 is fixed so as to move simultaneously with the movement of the partition plate 37 in order to always receive vibration transmission of the partition plate 37.

  Here, the granular material 35 causes brittle fracture due to low-frequency vibration or static force, and high-frequency crushing sound is generated at that time. Specific examples include gravel, concrete, mortar, brick, rock, glass, metal sphere, and hard plastic.

  According to the above configuration, when the intruding vehicle passes at a low speed on the road in which the device 31 is embedded, the low frequency vibration generated by the passage is transmitted to the granular material 35 via the lid 39. The partition plate 37 moves in the horizontal direction due to the high-frequency vibration generated by the granular bodies 35 rubbing and moving in a complicated manner, or the high-frequency vibration is applied to the optical fiber cable arranged so as to be in contact with the partition plate 37. Is transmitted. As a result, the presence or absence of an intruding vehicle can be detected.

  Although not shown, a mechanism is provided to return the partition plate 37 to a predetermined position in preparation for the vibration detection again when the granular material 35 bursts and the partition plate 37 moves in the horizontal direction. . Thereby, even when there is a continuous passage of the vehicle, the situation can be detected sequentially.

  In this embodiment, the partition plate 37 is arranged vertically, but the partition plate 37 may be arranged horizontally. In this case, since a space is formed above and below via the partition plate 37, an optical fiber is disposed in the lower space, and the upper space is filled with the granular material 35. The granular material 35 is further covered with a lid and camouflaged with soil or the like. According to this configuration, when the intruding vehicle passes over the device 31, the granular material 35 is ruptured by slow low-frequency vibration, and this energy is converted into high-frequency vibration to move the partition plate 37. High frequency vibration can be transmitted to the optical fiber cable. Thereby, even if the intruding vehicle enters the management area at a low speed, the intrusion can be detected.

  In this case as well, an elastic material such as a winding screw is interposed so as to support the bottom surface of the groove and the partition plate 37 vertically so that the partition plate 37 returns to a fixed position in the same manner as described above, so that vibration caused by passing through the vehicle The partition plate is configured to return to a fixed position when vibration is stopped while being transmitted to the fiber.

  Next, the configuration of the intruder detection device 41 according to the fourth embodiment will be described with reference to FIGS. 4A is an overall configuration diagram of the intruder detection device 43, and FIG. 4B is a configuration sectional view of FIG. 4A. In the following description of the present embodiment, the same components as those in the first and second embodiments are denoted by the same reference numerals, and the description thereof is omitted.

  This intruder detection device 41 is different from the installation method of the pipe 7 installed inside or outside the upper or lower beam of the fence 3 in the first and second embodiments. It differs from the above embodiment in that a tube 7 is provided between the muscles. In the present embodiment, the tube 7 is fixed to the fence 3 with a fixing bracket 41.

  According to such a configuration, the strength in the laying direction of the fence 3 can be increased because the tube 7 is provided facing the line while obtaining the same effects as those of the first and second embodiments. At this time, while increasing the strength of the fence, the vibration generated when the intruder gets over the fence 3 can be transmitted as before.

  In addition, the laying method of the pipe | tube 7 and the optical fiber cable 5 demonstrated in the said 1st, 2nd and 4th embodiment can be combined suitably according to the monitoring level of a management area. Thereby, compared with the case where said 1 embodiment is applied, the detection accuracy can be raised and the possibility of erroneous detection can be reduced. In addition, by combining multiple laying methods, even if one of the optical fiber cables breaks or breaks down, other detectors function, improving reliability and reducing downtime Can be made.

  In the first, second, and fourth embodiments described above, the optical fiber ring interference type sensor is applied. However, instead of this sensor, the optical fiber ring interference type sensor shown in FIG. 5 may be applied. good. At this time, the four optical fiber cables of the optical fiber cables La and Lb are accommodated in the optical fiber cable accommodated in the tube. The principle of this optical fiber ring interference type sensor is described in detail in Patent Document 2.

  That is, the optical fiber ring interference sensor 51 detects the vibration amount using the phase difference detection process disclosed in Patent Document 1 based on optical signals having two different wavelengths λ1 and λ2. Two detection units 45a and 45b are provided, and the first and second detection units 45a and 45b share one shared fiber ring La and Lb.

  In addition, the optical fiber ring interference sensor detects two interference light intensities simultaneously by the first and second detection units 45a and 45b, and specifies the excitation point p based on the two detected interference light intensities. , And / or the phase change amount at the excitation point p is calculated.

  A specific operation will be described here. As shown in FIG. 5, the optical signal S (λ 1) having the wavelength λ 1 emitted from the light emitting element 1 (or the optical input terminal 1) is branched by the optical branching coupling element 1.

  One of the branched optical signals S (λ1) propagates clockwise through the shared fiber rings La and Lb.

  That is, the optical signal S (λ1) is a connection optical fiber having an optical path length Lc, a wavelength division branching element 1, a loop optical fiber having an optical path length La, a wavelength division branching element 3, and a connection light having an optical path length Lg. The fiber, the wavelength division branch element 4, the loop optical fiber having the optical path length Lb, the wavelength division branch element 2 and the connecting optical fiber having the optical path length Le are propagated and input to the optical branch coupling element 1.

  On the other hand, the other first optical signal S (λ1) branched by the optical branching coupling element 1 propagates counterclockwise in the shared fiber ring.

  That is, the other branched optical signal S (λ1) is a connection optical fiber having an optical path length Le, a wavelength division branch element 2, a loop optical fiber, a wavelength division branch element 4, and a connection light having an optical path length Lg. The fiber, the wavelength division branching element 3, the loop optical fiber, the wavelength division branching element 1, and the connecting optical fiber having the optical path length Lc are propagated and input to the optical branching coupling element 1.

  As a result, the two optical signals branched through the optical branching and coupling element 1 propagate through the shared fiber ring (optical path length Lc + La + Lg + Lb + Le) clockwise and counterclockwise, respectively, and then are coupled (combined by the optical branching and coupling element 1). And is input to the light receiving element 1 and detected as the intensity of interference light (an electric signal indicating the intensity of interference light).

  Similarly, the optical signal S (λ2) having the wavelength λ2 emitted from the light emitting element 2 is branched by the optical branching coupling element 2, and one branched optical signal S (λ2) rotates clockwise through the shared fiber ring. (The optical path length Lf + Lb + Ld + La + Lh) and the other optical signal S (λ2) branched and input to the optical branching coupling element 2 propagates in the shared fiber ring in the clockwise direction (optical path length Lh + La + Ld + Lb + Lf) Input to the branch coupling element 2.

  Then, the counterclockwise propagation light and the clockwise propagation light are coupled (combined) by the optical branching and coupling element 2 and input to the light receiving element 2 to obtain interference light intensity (an electric signal representing the interference light intensity). Detected.

  At this time, the phase difference θ1 of the interference light C (λ1) (clockwise propagation light and counterclockwise propagation light) observed by the light receiving element 1 is expressed by the following expression (1).

[Equation 1]
θ1 (t) = φ1 {t− (Lp + Lc + Lj) · n / c}
−φ1 {t− (La−Lp + Lg + Lb + Le + Lj) · n / c}
+ Θ10 (1)
Further, the phase difference θ2 of the interference light C (λ2) (clockwise propagation light and counterclockwise propagation light) observed by the light receiving element 2 is also expressed by the following equation (2).

[Equation 2]
θ2 (t) = φ2 {t− (Lp + Ld + Lb + Lf + Lm) · n / c}
-Φ2 {t- (La-Lp + Lh + Lm) · n / c} + θ20 (2)
Here, φ1 and φ2 are the phase fluctuation amounts of the optical signal S (λ1) and the optical signal S (λ2) at the excitation point p, respectively, and θ10 and θ20 are the static states of the phase differences θ1 and θ2, respectively. Is the initial phase difference. Lj is the optical path length between the optical branching coupling element 1 and the light receiving element 1, and Lm is the optical path length between the optical branching coupling element 2 and the light receiving element 2.

Furthermore, since φ1 and φ2 are caused by the same optical path length variation,
[Equation 3]
λ1φ1 = λ2φ2 (3)
It becomes.

  If the configuration (measurement system) of the optical fiber ring interference sensor is determined, the unknowns in the above formulas (1) to (3) are the distance Lp from the wavelength division branching element 1 to the excitation point p, the phase fluctuation amount φ1, and Since only φ 2, that is, 3 unknowns, by solving the three simultaneous equations (1) to (3), the distance Lp from the wavelength division branch element 1 to the excitation point p, the optical signal S (λ 1) And phase fluctuation amounts φ1 and φ2 of the optical signal S (λ2) can be obtained, respectively.

  By applying this optical fiber ring interference type sensor 51, the excitation point can be detected with high accuracy. That is, the difference from the sensor applied to the first embodiment is that the first embodiment can detect that someone has entered, but it can detect from which position it has entered. It is not possible. However, if the optical fiber ring interference type sensor 51 shown in FIG. 5 is applied, the intrusion path can be specified with high accuracy.

  Next, an arrangement example of the intruder detection device described in the first to fourth embodiments will be described with reference to FIG.

  The management area shown in FIG. 6 assumes a port. In such a place, since a part of the management area is a quay, it is divided into a place where the fence 3 is laid in a straight line and a place where the fence is laid so as to surround a specific area. When laying in a straight line, it is preferable to apply the optical fiber ring interference type sensor 51 shown in FIG. This makes it easy to identify the intruder's intrusion route even around a large site.

  On the other hand, when the fence 3 is laid in an annular shape so as to surround a specific area, any one of the intruder detection devices shown in the first, second, and fourth embodiments, or a combination thereof, is used. Highly reliable detection can be realized by laying together. In addition to the conventional locking, the intruder detection device 31 shown in the third embodiment is embedded at the entrance of the vehicle below the passage.

It is a figure which shows the structure of the intruder detection apparatus 1 which concerns on the 1st Embodiment of this invention. It is a figure which shows the structure of the intruder detection apparatus 21 which concerns on the 2nd Embodiment of this invention. It is a figure which shows the structure of the intruder detection apparatus 31 which concerns on the 3rd Embodiment of this invention. It is a figure which shows the structure of the intruder detection apparatus 41 which concerns on the 4th Embodiment of this invention. It is a figure which shows the modification of the intruder detection apparatus which concerns on 1st thru | or 4th embodiment. It is a figure which shows the example of application of the intruder detection apparatus which concerns on the 1st thru | or 4th embodiment of this invention. It is a figure which shows the structure of the conventional intruder detection apparatus 101. FIG.

Explanation of symbols

1, 21, 31, 43 ... Intruder detection device 3 ... Fence 5 ... Optical fiber cable 7 ... Tube 9 ... Fixing bracket 11 ... Post 13 ... Optical fiber ring interference type sensor 17, 25, 27 ... Support bracket 19 ... Duct 23 DESCRIPTION OF SYMBOLS ... Cover 35 ... Granular body 37 ... Partition plate 39 ... Cover 41 ... Fixing bracket 51 ... Optical fiber ring interference type sensor 101 ... Intruder detection device 103 ... Fence 105 ... Detection wire 107 ... Monitoring ITV camera 109 ... Interlock device 111 ... Power cable 113 ... Power panel

Claims (4)

An optical branching and coupling element is connected to the end of a loop-shaped optical fiber laid so as to surround the monitoring area, and the light emitted from the light source is incident on the end of the optical fiber to pass through the optical fiber. An intruder detection device having an optical fiber ring interference type sensor that calculates an excitation point applied on an optical fiber from a difference in time change of the optical path length of the propagation light after propagating clockwise and counterclockwise Because
Intrusion characterized in that the optical fiber is laid along the upper or lower beam of the fence surrounding the surveillance area, and all or part of the optical fiber is housed in a cylindrical tube Person detection device.   A vibration transmitting metal fitting that excavates a groove along the laying direction of the fence in the ground where the fence is installed, and physically connects the column supporting the fence and the pipe installed in the groove. The intruder detection device according to claim 1, wherein the intruder detection device is embedded in the ground so that the pipe cannot be identified from the outside.   Divide the groove formed in the ground of the monitoring area with a movable partition plate, place the optical fiber in contact with the partition plate in one groove, and convert low frequency vibration to high frequency vibration in the other groove The intruder detection device according to claim 1, wherein the intruder detection device is embedded in the ground so as to be indistinguishable from outside by filling the brittle material to seal the groove.   The optical fiber ring interference type sensor uses a fiber ring portion including a loop-shaped optical path formed by using an optical fiber to calculate a phase difference between interference lights of the first and second optical signals having different wavelengths. The intruder detection device according to any one of claims 1 to 3, wherein the intruder detection device is an optical fiber ring interference type sensor that obtains and specifies an excitation point generated on the optical fiber ring portion.

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