JP2009031000A - Metal body detection system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To easily provide a metal body detection system at low costs through the use of GPS, focusing on that a metal body, such as, a rolling stock and an automobile shields GPS radio waves. <P>SOLUTION: The metal body detection system is provided with a GPS antenna 11 for receiving GPS radio waves 17; a GPS receiver 12 for outputting positioning results by processing GPS signals acquired via the antenna 11; and a determination device 14 for determining the success on the failure of reception of radio waves, on the basis of output S of the receiver 12, determining the absence of the metal body 15, when the reception of radio waves is successful, and determining the presence of the metal body 15, when the reception of radio waves is not successful. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a metal object detection system that detects the presence or absence of a metal object such as a railway vehicle or an automobile as a detection target, and more specifically, a GPS (Global Positioning Satellite) satellite for a satellite positioning system (Global Positioning System). The present invention relates to a metal object detection system that detects whether or not a detection target exists by using a GPS radio wave.

As a method for detecting a metal object including a railway vehicle, a rail circuit method is widely used in a railway vehicle to detect its presence by short-circuiting the left and right rails on the vehicle axle (for example, Patent Document 1). reference). In addition, a loop coil system using the fact that the transmission frequency changes due to the presence of a metal object (see, for example, Patent Document 2), and the light sent from the light emitter to the light receiver is blocked by the object containing metal A photo interrupter method for detecting the presence of an object has been put into practical use.
Moreover, as a detection system using GPS, a GPS antenna and a GPS receiver are mounted on a moving body such as a tram to detect an operation position (see, for example, Patent Document 3), a GPS antenna or the like is fixed to the ground. Among them are those that measure crustal deformation.

JP 2000-168554 A Japanese Patent Laying-Open No. 2005-233883 Japanese Patent Laid-Open No. 2006-240478

Since such a GPS-based detection system uses GPS radio waves that can be received free of charge, there is no need to provide a transmitter on its own, and the cost can be reduced accordingly.
In addition, it can receive radio waves from multiple GPS satellites, and each radio wave contains multiple pieces of information such as time information and position information. By doing so, the accuracy and accuracy of object detection and response time can be specified.
However, the conventional GPS-based system measures the position but does not detect the presence or absence of an object.

On the other hand, a conventional object detection system that does not use GPS detects whether or not it can be received while transmitting radio waves or the like. For this reason, the presence or absence of an object can be determined according to whether or not the transmission signal is blocked by the detection target.
However, since not only the receiver but also the transmitter has to be provided on its own, the cost increases accordingly. In addition, in order to perform detection reliably, there is a need for a means for making the radio waves unique and discriminating between normal radio waves and noise by adding an ID (identification code) or modulating the radio waves to be transmitted and received. It is.
Therefore, focusing on the fact that metal objects such as railway vehicles and automobiles block GPS radio waves, it is a technical problem to realize a metal object detection system simply and inexpensively by using GPS.

The metal object detection system of the present invention (Solution 1) was created to solve such a problem, and a GPS antenna for receiving GPS radio waves, and a GPS signal obtained through this antenna. A GPS receiver that outputs positioning results and determines the success or failure of radio wave reception based on the output of this receiver, determines that there is no metal object when radio wave reception is successful, and metal wave when radio wave reception fails And a determination device that determines that an object is present.
Note that the GPS antenna, the GPS receiver, and the determination device may be individually mounted or integrally mounted. Further, the metal object is not limited to a pure metal, and any other material may be combined with the metal as long as it can block GPS radio waves. A typical example of a detection object made of a metal object is a moving object such as a railway vehicle or an automobile, but here it is a detection object if it can be moved or transported even if it is an unmovable figurine. Can be.

Further, the metal object detection system of the present invention is (Solution means 2), which is the metal object detection system of the above-described solution means 1, and the GPS from the sky to the GPS antenna when the metal object arrives in the movement path of the metal object. The GPS antenna is provided in a place where the radio wave is blocked and the GPS radio wave reaches the GPS antenna from above when the metal object leaves.
Here, the metal object to be detected is limited to the moving object, but the moving object may pass through the detection target position, return at the detection target position, or temporarily stop at the detection target position. There may be.

  Further, the metal object detection system of the present invention (Solution means 3) is the metal object detection system of the above solution means 1, provided with a radio wave reflector that reflects GPS radio waves, and the radio wave reflector and the GPS antenna. Are opposed to both sides of the movement path of the metal object, and when the metal object arrives, the GPS radio wave from the radio wave reflector to the GPS antenna is blocked, and when the metal object leaves, the GPS wave is reflected from the radio wave reflector to the GPS object. It is characterized in that GPS radio waves reach the antenna.

  Further, the metal object detection system of the present invention (solution 4) is the metal object detection system of the solution 3, wherein GPS radio waves from the sky to the GPS antenna are shielded from the radio wave reflector to the GPS antenna. It is characterized by having a radio wave shield that does not shield GPS radio waves.

In such a metal object detection system of the present invention (Solution 1), the GPS antenna is not mounted on the metal object to be detected, but is installed toward the place where the metal object is to be detected. . In addition, when the metal object is present at the detection target position, GPS radio waves to the GPS antenna are blocked by the metal object. However, if the metal object is not present at the detection target position, the GPS radio wave reaches the GPS antenna. Keep it like that. If it does so, determination of a determination apparatus will be performed according to the presence or absence of the arrival of the GPS electromagnetic wave to the GPS antenna, and the presence or absence of a metal object will be detected.
Thus, by removing the GPS antenna from the object to be detected and determining whether or not a metal object is present (presence / absence) according to whether or not GPS radio waves can be received, it is not possible to provide a facility for transmitting radio waves by itself. However, since the presence / absence of an object can be detected, the configuration is simplified and the cost is reduced as much as unnecessary transmission equipment.

  GPS (Global Positioning System) is a system that calculates the position (latitude / longitude / altitude) of a receiver using radio waves transmitted by artificial satellites. The price is very cheap. The present invention is a widespread and stable GPS that is applied to a detection system for the presence of a metal object instead of the original positioning, and detects the presence or absence of a GPS radio wave from an artificial satellite blocked by a metal object. By detecting this, it has the advantages of the conventional object detection system and the GPS utilization system.

Specifically, since the GPS antenna and the GPS receiver can be installed outside the detection target while using the GPS, the installation and maintenance are easy and the convenience is excellent.
In addition to receiving radio waves from multiple GPS satellites, each radio wave contains unique information such as time information and position information. Regular radio waves and noise can be discriminated.
Therefore, according to the present invention, the metal object detection system can be realized simply and inexpensively.

  In the metal object detection system of the present invention (solution 2), a GPS antenna is provided in the movement path of the metal object so that GPS radio waves are blocked only when the metal object arrives. It is possible to detect the coming and going (advance advance / pass / pause). It can also be detected from a moving path outside the moving body with a simple and inexpensive system using GPS.

  Furthermore, in the metal object detection system of the present invention (Solution means 3), after introducing a radio wave reflector, the GPS antenna and the GPS antenna are arranged opposite to both sides of the movement path of the metal object, and the radio wave reflector Since the GPS radio wave reaching the GPS antenna via the radio wave is cut off only when the metal object arrives, the detection of the moving object from the outside of the moving object can be detected by a simple and inexpensive system using GPS. This can be done from outside the travel route. Therefore, the present invention can be applied not only to a moving body but also to environments and facilities where it is not desired to install a GPS antenna or the like on a moving path. In addition, since the radio wave reflector can be prepared easily and inexpensively from the transmission equipment that emits radio waves, the advantage of realizing the metal object detection system easily and inexpensively can be inherited without losing.

  Further, in the metal object detection system of the present invention (solution 4), by providing a specific radio wave shield, it is possible to prevent unwanted GPS radio waves from the sky even if the GPS antenna is not directed downward or obliquely downward. A desired reflected wave can be received avoiding reception. Therefore, the installation conditions of the radio wave reflector and the GPS antenna are alleviated, and the convenience is further improved. Moreover, radio wave shields can be prepared more easily and cheaply than radio wave reflectors, and even if radio wave shields and radio wave reflectors are used in combination, they are simpler and less expensive than having their own transmission facilities. The advantage of simply and inexpensively realizing the object detection system is also inherited.

About the metal object detection system of such this invention, the specific form for implementing this is demonstrated by the following Examples 1-3.
The embodiment 1 shown in FIG. 1 is an embodiment of the above-described solution 1 (claim 1 at the time of filing) as an figurine detection system, and the embodiment 2 shown in FIG. 2 is the solution 2 described above. (Claim 2 at the beginning of the application) is embodied as a parking detection system, and the third embodiment shown in FIG. 3 uses the above-described solving means 3 to 4 (claims 3 to 4 at the beginning of the application) for train detection. It is embodied as a system.

  A specific configuration of the figurine detection system 10 that is Embodiment 1 of the metal object detection system of the present invention will be described with reference to the drawings. FIG. 1A is a perspective view of the figurine detection system 10.

The figurine detection system 10 includes a GPS antenna 11, a GPS receiver 12, a determination device 13, and an alarm speaker 14.
The GPS antenna 11 may be a commercially available general-purpose product as long as it can receive GPS radio waves transmitted from GPS satellites, and the mounting form is arbitrary such as a film form or a plate form.
The GPS receiver 12 is connected to the GPS antenna 11 by a coaxial cable, a BNC connector, or the like, and is a commercially available general-purpose product as long as it processes a GPS signal obtained through the GPS antenna 11 and outputs a positioning result. It ’s enough. The output S generally includes time information and position information, but it is easy to use a receiver that outputs a GPS radio wave reception level as a numerical value or a logical value.

  The determination device 13 is a logical operation unit mainly composed of, for example, a microprocessor or a digital signal processor. The determination device 13 inputs the output S of the GPS receiver 12 as needed, and determines the success or failure of radio wave reception based on the output S. ing. The determination of the success or failure of radio wave reception is sufficient if the reception level of the GPS radio wave is included in the output S of the GPS receiver 12 as a logical value indicating whether it is correct or not. In some cases, binarization is performed with an appropriate threshold value, and when the reception level is not included in the output S, it is performed depending on whether time information and position information are within the normal range. .

  In addition, each time the determination device 13 determines whether or not radio wave reception is successful, the determination device 13 determines that there is an object (metal object) to be detected when the radio wave reception is unsuccessful. It is determined that there is no sound, and an alarm sound is emitted from the alarm speaker 14. In order to prevent an excessive reaction or the like, an alarm sound is generated only when the state of unsuccessful reception of radio waves has exceeded a predetermined set time. Further, the determination device 13 can specify the accuracy / accuracy of object detection and the response time by utilizing the presence of a plurality of GPS satellites.

  That is, since each GPS radio wave received by the GPS antenna 11 from a plurality of GPS satellites includes a plurality of information such as time information and position information, a determination device that can input the information via the GPS receiver 12 13 can specify the accuracy / accuracy and response time of object detection by selecting appropriate information from the information as determination requirements for object presence detection according to the usage mode. For example, in a system where priority is given to detecting that there are no figurines for safety reasons, GPS signals from a plurality of (four here) GPS satellites received before placing the figurine. If all four of them are cut off, it is determined that the figurine exists, and conversely, if there is reception of GPS radio waves even from one, and the time information and position information included therein are appropriate, it is determined that there is no figurine. It has become.

  The use mode and operation of the figurine detection system 10 of the first embodiment will be described with reference to the drawings. FIG. 1B is a side view of the installation location of the figurine detection system 10.

The object 15 to be detected may be a movable object that can block the GPS radio wave 17 transmitted from the GPS satellite 16 to the ground. For example, it may be a bronze sculpture in an outdoor exhibition or in front of a warehouse. Or a towed steel trailer parked in
In the figurine detection system 10, at least the GPS antenna 11 is installed obliquely below the north side of the figurine 15 in order to detect the presence / absence of the figurine 15. This is a typical example where the GPS radio wave 17 from the GPS satellite 16 is blocked by the figurine 15 and does not reach the GPS antenna 11, but may be installed at other locations as long as the radio wave blocking condition is satisfied. If there is a sufficient space or gap under the figurine 15, it may be installed there.

Then, the direction of the GPS antenna 11 is adjusted so that the radio wave reception direction is directed to the figurine 15, and if there is no figurine 15, the GPS radio wave 17 is directed to the direction in which the GPS radio wave 17 can be received.
When the figurine detection system 10 is operated after installation, the GPS radio wave 17 is blocked by the figurine 15 and does not reach the GPS antenna 11 while the figurine 15 is present at the tip of the GPS antenna 11. Is not received, the determination device 13 determines that the figurine 15 exists based on the output S of the GPS receiver 12 reflecting this, and the alarm speaker 14 keeps quiet correspondingly.

When the figurine 15 disappears from the tip of the GPS antenna 11 due to being taken away or the like while the figurine detection system 10 is in operation, the GPS radio wave 17 reaches the GPS antenna 11 and the GPS radio wave 17 is received and reflected. Since the output S is sent from the GPS receiver 12 to the determination device 13, the determination device 13 determines that the figurine 15 does not exist based on the output S, and an alarm sound is generated from the alarm speaker 14 correspondingly. Be emitted.
Thus, in the figurine detection system 10, the presence or absence of the figurine 15 is detected at any time, and when the figurine 15 disappears, this is notified by an alarm sound.

  About the parking detection system 20 which is Example 2 of the metal object detection system of this invention, the specific structure is demonstrated referring drawings. FIG. 2A is a perspective view of the parking detection system 20.

The parking detection system 20 is different from the above-described figurine detection system 10 of the first embodiment in that the alarm speaker 14 is omitted and the parking management device 21 is introduced, and the determination device 13 parks the determination result. This is the point that it is sent to the management device 21.
The parking management device 21 includes, for example, a computing device / control device mainly composed of a computer and a sequencer. In order to manage the entire parking lot, the parking management device 21 inputs a determination result from a single or a plurality of parking detection systems 20 and parks. The parking time is measured for each section, and the fee calculation, money receipt, gate opening / closing control and the like are performed based on the parking time and input data by key operation.

  About the parking detection system 20 of this Example 2, the use aspect and operation | movement are demonstrated referring drawings. FIG. 2B is a plan view of a parking lot where the parking detection system 20 is installed.

  In this example, since the automobile (metal object, moving body) parked in the time-rented parking lot is the detection target, seven parking detection systems 20 equal to the number of parking sections 23 forming the branch path of the movement path 22 are introduced. The GPS antennas 11 are arranged one by one in the parking section 23. The GPS antenna 11 is installed in front of the tire stopper in the parking section 23 in order to detect an improper parking where the automobile is stopped before the tire stopper, and is installed upward to receive GPS radio waves from the GPS satellite. Is done. The GPS receiver 12 and the determination device 13 are collectively stored in a housing together with the parking management device 21, but may be dispersed.

After the installation, when the parking detection system 20 and the parking management device 21 are operated, the GPS radio waves reach the GPS antenna 11 of any parking section 23 until the vehicle is parked. It is determined that there is no data, and the determination result is collected in the parking management device 21.
In the meantime, if a car is parked in any of the parking sections 23, the GPS radio wave is blocked by the car and cannot be received by the GPS antenna 11 in the parking section 23. (That is, a determination that a car is present) is issued, and the parking management device 21 starts measuring the parking time.

After that, when the parked car departs and exits from the parking section 23, the GPS radio wave again reaches the GPS antenna 11 of the parking section 23, and the corresponding determination device 13 determines whether there is no parking ( That is, the determination that the vehicle does not exist is issued, and the parking time measurement by the parking management device 21 is completed.
Thus, in the parking detection system 20, the presence or absence of parking in the parking section 23 where the GPS antenna 11 is installed is detected at any time. In addition, the parking time is measured by the parking management device 21 that has input the information, and processing such as charge calculation is also performed.

  A specific configuration of a train detection system 30 that is Embodiment 3 of the metal object detection system of the present invention will be described with reference to the drawings. FIG. 3A is a perspective view of the train detection system 30.

This train detection system 30 differs from the above-described figurine detection system 10 of the first embodiment in that a radio wave reflector 31 and a radio wave shield 32 are added, and the alarm speaker 14 is omitted instead. The wireless device 33 is introduced.
The radio wave reflector 31 reflects a GPS radio wave sent to the ground from an overlying GPS satellite, and a radio wave reflector 31 that can send a reflected wave horizontally or obliquely upward is easy to use. A low-cost metal flat plate may be used, but if it is desired to focus GPS radio waves, a concave plate like a parabolic antenna may be used. Since this is installed separately from the main bodies 11-13, it is preferable to equip with the support | pillar which can adjust height or angle-of-attack adjustment.

The radio wave shield 32 shields GPS radio waves flying downward from the sky to the GPS antenna 11, while not blocking GPS radio waves flying sideways from the radio wave reflector 31 disposed opposite to the GPS antenna 11. 11 is composed of a metal plate covering the upper part of 11 and its support part. However, if it is desired to shield an undesired reflected wave from the other, a metal box having an opening only on the radio wave reflector 31 side may be adopted.
The wireless device 33 may be an inexpensive commercial product as long as it can wirelessly transmit the determination result of the determination device 13 to the central device or the repeater, for example, it may conform to a specific low power wireless standard suitable for short-range communication, It may be one that conforms to the standard of business radio that can be used for longer distances.

  Further, the determination device 13 has the following function expansion using the fact that there are a plurality of GPS satellites 16 and each GPS radio wave 17 includes a plurality of information such as time information and position information. . In other words, in the train detection system 30 for railways that detect trains (metal objects, moving objects), because it is desired to detect the presence of the train 35 in order to ensure safety, the determination device 13 receives the information. If one of the GPS radio waves 17 from the plural (four here again) GPS satellites 16 stops, it is determined that the train is “present” (there is a train), and conversely from all four It is determined whether or not the GPS radio wave 17 is received and the time information and position information included therein are appropriate, and it is determined that the train is “absent” (no train exists) only when it is valid. By such function expansion, the determination device 13 of the train detection system 30 has improved accuracy and accuracy of object detection.

  About the train detection system 30 of this Example 3, the use aspect and operation | movement are demonstrated using drawing. FIGS. 3A and 3B show the state of the track by the train detection system 30, where FIG. 3B is a plan view and FIG. 3C is a front view.

When the train detection system 30 is installed to detect the train 35 (metal object, moving body) traveling on the rail 34 (track, moving path), the GPS antenna 11, the radio wave reflector 31, and the radio wave shield 32 are connected to the rail 34. However, since the GPS receiver 12, the determination device 13, and the wireless device 33 are not specially restricted, they may be installed where maintenance work is easy.
The GPS antenna 11 and the radio wave reflector 31 are arranged on both sides of the rail 34 so as to face each other. The radio wave shield 32 is provided in a place covering at least the upper part of the GPS antenna 11. The installation height of the GPS antenna 11 and the radio wave reflector 31 is set above the rail 34 and further between the bottom and the ceiling of the train 35 and avoiding windows.

After the installation, the GPS radio wave 17 that has come directly from the sky is always blocked by the radio wave shield 32 and is not received by the GPS antenna 11 regardless of the operating state of the train detection system 30.
When the train detection system 30 is activated, until the train 35 enters, the GPS radio wave 17 that has come down from the sky and hits the radio wave reflector 31 is reflected there and turns sideways, and the GPS antenna 11 To reach. Further, in response to the successful reception, the determination device 13 determines that the train is “none”, and the notification is sent to a remote place via the radio device 33.

On the other hand, since the GPS radio wave 17 from the radio wave reflector 31 to the GPS antenna 11 is blocked when the train 35 arrives, a detailed description that will not be repeated will be omitted. 13 determines that the train is “present”, and the notification is sent to the remote location via the radio 33.
Furthermore, since the GPS radio wave 17 arrives again from the radio wave reflector 31 to the GPS antenna 11 when the train 35 runs away, the determination device 13 determines that the train is “none” in response to the successful reception of the GPS radio wave 17. The notification is sent to the remote place via the radio device 33.
In this way, in the train detection system 30, since the arrival of the train 35 is detected at any time, it can be used for traveling monitoring at a remote place, warning to the site of track construction, and the like.

[Others]
In the above-described embodiment, the GPS antenna, the GPS receiver, and the determination device are separated from each other and connected by wire. However, these may be integrated as appropriate when mounting, or may be wirelessly connected. For example, a mobile phone with a GPS function is adopted as a GPS antenna and a GPS receiver, a mobile phone is placed at a position where a metal object is to be detected, and the detection result is notified to a remote determination device by the communication function of the mobile phone. You may make it do.
Further, the size of the detection target object can be changed by changing the effective area of the GPS antenna installed on the ground side, or by changing the separation distance between the GPS antenna and the closest surface of the metal object to be detected. .
In the first embodiment, an alarm sound is output from the alarm speaker 14 when the figurine 15 is not present, but the reverse is also possible.

  Since the metal object detection system of the present invention can detect the metal object to be detected from the outside, for example, detecting the entry and advancing of the railway vehicle from the track or side of the railway vehicle, an automobile Detecting the parking departure of a car from the parking lot side where the car is parked, detecting the entry / exit of a car at the entrance / exit of the rental parking lot, or detecting whether a metal object placed at a predetermined position is continuously installed or removed It can be applied to doing things.

About Example 1 of this invention, the structure and usage aspect of a metal object detection system are shown, (a) is a perspective view of a detection system, (b) is a side view of an installation location. About Example 2 of this invention, the structure and usage condition of a metal object detection system are shown, (a) is a perspective view of a detection system, (b) is a top view of an installation location. About Example 3 of this invention, the structure and usage aspect of a metal object detection system are shown, (a) is a perspective view of a detection system, (b) is a top view of an installation location, (c) is a front view of an installation location. is there.

Explanation of symbols

10: Figurine detection system (metal object detection system),
11 ... GPS antenna, 12 ... GPS receiver, 13 ... determination device,
14 ... Notification speaker, 15 ... Figurine (metal object),
16 ... GPS satellites, 17 ... GPS radio waves,
20 ... Parking detection system (metal object detection system),
21 ... Parking management device, 22 ... Moving route, 23 ... Parking section,
30 ... Train detection system (metal object detection system),
31 ... Radio wave reflector, 32 ... Radio wave shield, 33 ... Radio device,
34 ... rail (track), 35 ... train (metal object)

Claims (4)

  A GPS antenna for receiving GPS radio waves, a GPS receiver that processes GPS signals obtained via this antenna and outputs positioning results, and whether radio wave reception is successful or not is determined based on the output of this receiver. A metal object detection system comprising: a determination device that determines that a metal object does not exist when radio wave reception is successful and determines that a metal object exists when radio wave reception fails.   Of the movement path of the metal object, when the metal object arrives, the GPS radio wave from the sky to the GPS antenna is blocked, and when the metal object leaves, the GPS radio wave reaches the GPS antenna from the sky, The metal object detection system according to claim 1, further comprising a GPS antenna.   A radio wave reflector that reflects GPS radio waves is provided, and the radio wave reflector and the GPS antenna are disposed opposite to both sides of the movement path of the metal object, and when the metal object arrives, the radio wave reflector and the GPS antenna are disposed. 2. The metallic object detection system according to claim 1, wherein when the metallic object is blocked by the GPS electromagnetic wave, the GPS electromagnetic wave reaches the GPS antenna from the electromagnetic wave reflector.   4. The metal object detection system according to claim 3, further comprising: a radio wave shield that shields GPS radio waves from above to the GPS antenna but does not shield GPS radio waves from the radio wave reflector to the GPS antenna.

Images