Positioning system and positioning method

Abstract

To improve the accuracy of position estimation using a beacon.SOLUTION: A positioning system includes a positioning device. The positioning device comprises a plurality of combinations of: a receiver which receives a beacon signal transmitted by a beacon transmitter and measures radio wave intensity; and a shield housing which houses the receiver and suppresses transmission of electromagnetic waves. The positioning device specifies a receiver closest to the beacon transmitter based on the radio wave intensity measured by each of the receivers. Each of the receivers communicates with a beacon transmitter received in a shielded housing having the receiver.SELECTED DRAWING: Figure 4

Description

[Technical field]

[0001] The present invention relates to a positioning system and a positioning method using a beacon. [Background technology]

[0002] There are beacons (radio signals) that transmit electromagnetic waves and other information to receivers, such as their location. Some beacons use Bluetooth (registered trademark). Generally, by receiving identification information from multiple transmitters, the receiving device can know its own location (for example, Patent Document 1).

[0003] Also, a technology has been proposed in which an opening is formed in a reader that reads information from an RF tag attached to a product, and a shield part that houses the product through the opening and an antenna that emits radio waves to communicate with the RF tag attached to the housed product are provided (for example, Patent Document 2). [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Special Publication No. 2010-531973 [Patent Document 2] JP 2018-190255 A Summary of the Invention [Problem to be solved by the invention]

[0005] Conventionally, to determine the location of a moving object such as a person or object, a method has been adopted in which radio waves from a transmitter attached to the object are received by multiple receivers, and a determination is made based on the signal strength of the radio waves received by each receiver.

[0006] On the premise that the transmitter and receiver are placed bare and the nearest receiver to be paired with the transmitter is identified using only RSSI (signal strength of received radio waves), factors such as the relative positions of the antennas, multipath fading, and attenuation due to obstacles can have a significant effect on the strength of the radio waves received by the receiver, particularly when the receivers are placed close to each other. Therefore, when determining the position of an object using multiple receivers, even if a transmitter is placed near a specific receiver, the received signal strength at another receiver may be strong, making it impossible to identify the nearest receiver and thus making it impossible to correctly determine the position of the transmitter.

[0007] An object of the present invention is to provide a technique for improving the accuracy of position estimation using a beacon. [Means for solving the problem]

[0008] In order to solve the above problems, the following measures are adopted. [1] a receiver that receives a beacon signal transmitted by the beacon transmitter and measures radio wave intensity; a shielding housing that houses the receiver and suppresses transmission of electromagnetic waves; A combination of a positioning device that identifies a receiver that is closest to the beacon transmitter based on the radio field strength measured by each of the receivers; Each of the receivers communicates with a beacon transmitter housed within a shielded enclosure that houses the receiver. Positioning system. [2] The shielding housing is a rectangular parallelepiped having an opening on one side. The beacon transmitter is attached in a predetermined orientation to a positioning object having a shape that determines an insertion direction with respect to the shield housing, The receiver is disposed in the shielded housing such that the polarization plane of the receiver's antenna coincides with the polarization plane of the antenna of a beacon transmitter that is inserted into the shielded housing together with the object to be located. [1] A positioning system as described in. [3] The shielding housing is a rectangular parallelepiped having an opening on one side. The beacon transmitter is attached in a predetermined orientation to a positioning object having a shape that determines an insertion direction with respect to the shield housing, A short side of a cross section of the object to be positioned perpendicular to the insertion direction is smaller than a short side of the opening of the shield housing, and a long side of the cross section is larger than the short side of the opening and smaller than the long side of the opening. [1] A positioning system as described in. [4] The short side of the cross section of the shield housing perpendicular to the insertion direction is equal to or larger than half the wavelength of the frequency band used by the beacon signal. A positioning system according to [2] or [3]. [5] The shield housing has a lid capable of closing the opening. A positioning system according to any one of [2] to [4]. [6] The combination of the receiver and the shielding housing is installed at a work site where a process constituting a series of operations is carried out, and the positioning device performs process management based on the receiver that is closest to the identified beacon transmitter. A positioning system according to any one of [1] to [5]. [7] The beacon transmitter is a Bluetooth Low Energy (BLE) beacon. 13. A positioning system according to any one of claims 1 to 6. [8] The shielding housing is made of metal. 13. A positioning system according to any one of claims 1 to 7. [9] A positioning method in which a computer identifies a receiver that is closest to a beacon transmitter based on radio wave intensity measured by a receiver that receives a beacon signal transmitted from the beacon transmitter, comprising: The receiver is housed in a shielded housing that suppresses the transmission of electromagnetic waves, and communicates with a beacon transmitter that is housed in the shielded housing that houses the receiver. Positioning method.

[0009] The disclosed aspects may be realized by a program being executed by an information processing device. That is, the disclosed configuration may be specified as a program for causing an information processing device to execute the processes executed by each of the means in the above-mentioned aspects, or a computer-readable recording medium on which the program is recorded. The disclosed configuration may also be specified by a method in which an information processing device executes the processes executed by each of the above-mentioned means. The disclosed configuration may also be specified as a system including one or more information processing devices that execute the processes executed by each of the above-mentioned means. Effect of the Invention

[0010] According to the present invention, it is possible to improve the accuracy of position estimation using a beacon. [Brief description of the drawings]

[0011] [Figure 1] FIG. 1 is a diagram illustrating an example of a system configuration. [Diagram 2] FIG. 2 is a diagram showing an example of a clear holder that houses a beacon. [Diagram 3] FIG. 3 is a diagram illustrating an example of functional blocks of a beacon. [Figure 4] FIG. 4 is a diagram showing an example of a shielded housing that houses a receiver. [Diagram 5] FIG. 5 is a diagram illustrating an example of a device configuration of a receiver. [Figure 6] FIG. 6 is a diagram illustrating an example of functional blocks of the server. [Figure 7] FIG. 7 is a diagram for explaining the operation sequence of the system. [Figure 8] FIG. 8 is a diagram for explaining the propagation of electromagnetic waves. [Figure 9] FIG. 9 is a top view for explaining a test configuration when shielded housings are adjacent to each other. [Figure 10]FIG. 10 is a top view for explaining a test configuration when a beacon is located outside a shielded housing. [Figure 11] FIG. 11 is a perspective view for explaining a test configuration in which a plastic housing is placed between two shielded housings. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0012] Hereinafter, an embodiment of the present invention will be described with reference to the drawings. The configuration of the embodiment is an example, and the configuration of the invention is not limited to the specific configuration of the disclosed embodiment. In implementing the invention, a specific configuration according to the embodiment may be appropriately adopted.

[0013] [Embodiment] System Configuration FIG. 1 is a diagram showing an example of the system configuration. In this embodiment, in addition to the radio beacon that is transmitted and received for positioning and the like, the transmitting and receiving device of the radio beacon is called a beacon. The radio beacon that is transmitted and received is also called a beacon signal. The transmitting device is also called a beacon transmitter or simply a transmitter, and the receiving device is also called a beacon receiver or simply a receiver. The system according to this embodiment includes beacons 10 (10A, 10B, . . .), receivers 20 (20A, 20B, 20C, . . .), and a server 30. The beacons 10 and the receivers 20 transmit and receive beacon signals by wireless communication. Each of the receivers 20 and the server 30 are connected to be able to communicate with each other via a network 4 by wire or wirelessly. The network 4 may include an IP (Internet Protocol) network, and the network 4 may include a beacon signal receiving device connected to the network 4. The devices can communicate based on a predetermined protocol. A part of the network 4 is a telephone network (fixed telephone network or mobile communication network), an ad hoc network, an intranet, a VPN (Virtual Private Network), a LAN (Local Area Network), etc. ), Wireless LAN, Wide Area Network (WAN), Internet, etc. In this embodiment, the receiver 20 is installed in a space such as a factory near a place where each of a plurality of processes constituting a series of procedures such as assembly and inspection is performed. The beacon 10 is used to identify an object to be processed in a plurality of processes, and is sent through the plurality of processes in sequence together with the object to be positioned, as shown by the dashed arrow in FIG. 1, for example. The server 30 identifies the receiver 20 closest to each beacon 10 based on the identification information of the beacon 10 detected by the receiver 20, and performs process management. The number of beacons 10 in the system and the number of receivers 20 to be installed are not limited to the example in FIG. 1, and are appropriately determined according to the number of processes, etc. The beacon 10 shown in FIG. 1 is attached to a clear folder (clear file) 100, and the receiver 20 is housed in a shielded housing 200.

[0014] 2 is a diagram showing an example of a clear holder 100 that holds the beacon 10. The clear holder 100 is made by folding, for example, a rectangular plastic sheet and joining the surrounding edges. The clear folder 100 may be a paper clip bound together in a booklet shape. The clear folder 100 may contain a document 101 on which information on the processing target in the above-mentioned process is written. In this embodiment, the clear folder 100 is the object to be located, and the user transfers the clear folder 100 between processes. The beacon 10 is attached to the clear folder 100. The beacon 10 is attached, for example, to the inside or outside of the clear folder 100. For convenience, the X-axis direction shown in FIG. 2 is referred to as the left-right direction (width direction), the Y-axis direction is referred to as the up-down direction, and the Z-axis direction is referred to as the depth direction. The object to be located is not limited to the clear folder, and may be a name holder, a binder, a card, a box, or other container.

[0015] FIG. 3 is a diagram showing an example of a functional block of the beacon 10 according to the embodiment. The beacon 10 includes a communication unit 11, a communication interface (IF) 12, and a storage unit 13. The communication unit 11 includes a CPU (Central Processing Unit) and a DSP (Digital Signal Processor). ) and operates by executing a program stored in the storage unit 13. The communication unit 11 transmits a radio tag including identification information for identifying the beacon 10 from the antenna 12 based on the information stored in the storage unit 13. The radio tag may include date and time information indicating the transmission time. Specifically, a technology such as BLE (Bluetooth Low Energy) may be used, and the radio tag may be broadcast. The communication IF 12 is an antenna connected to the communication unit 11 for transmitting the radio tag. The beacon 10 is preferably attached to the clear holder 100 in such a position that the polarization plane of the antenna faces a predetermined direction. The communication IF 12 may be a directional antenna having a higher sensitivity in a specific direction than in other directions. The storage unit 13 includes a main storage device such as a random access memory (RAM) or a read only memory (ROM), and a secondary storage device such as an erasable programmable ROM (EPROM), a hard disk drive (HDD, Hard Disk Drive), or a solid state drive (SSD, Solid State Drive). The storage unit 13 holds a program for executing the process according to the embodiment, various data, and various tables in a readable and writable manner. For example, the storage unit 13 stores identification information of the beacon 10.

[0016] FIG. 4 is a diagram showing an example of a shielded housing 200 that houses the receiver 20. For convenience, the X-axis direction shown in FIG. 4 is referred to as the left-right direction (width direction), the Y-axis direction is referred to as the up-down direction, and the Z-axis direction is referred to as the depth direction. The shielded housing 200 is a housing made of metal such as aluminum, and suppresses the transmission of electromagnetic waves. The shielded housing 200 may be a rectangular parallelepiped container having an opening 201 on one surface. In the example of FIG. 4, the shielded housing 200 has an opening on the entire top surface, and the clear holder 100 can be inserted through the opening 201. The size (gusset) of the shielded housing 200 in the depth direction is sufficiently larger than the size (thickness) of the clear holder 100 in the depth direction, and multiple clear holders 100 can be inserted at once. The Y-axis direction is referred to as the insertion direction. For example, a side surface of the shielded housing 200 may have an insertion hole 202 through which a power supply or communication cable connected to the receiver 20 is inserted. Since the shield housing 200 suppresses the transmission of the beacon signal, the receiver 20 housed in the shield housing 200 has difficulty detecting the beacon 10 present outside the shield housing 200. In addition, the receiver 20 housed in the shield housing 200 can detect the beacon 10 attached to the clear holder 100 inserted in the shield housing 200 with sufficient received radio wave intensity (RSSI).

[0017] FIG. 5 is a device configuration diagram showing an example of the receiver 20. The receiver 20 is a dedicated or general-purpose computer, and includes a processor 21 (beacon communication unit 211, communication unit 212), a communication IF 22, and a storage unit 23. The processor 21 is a processor such as a CPU or DSP, and operates as the beacon communication unit 211 and the communication unit 212 by executing a program stored in the storage unit 23. The beacon communication unit 211 receives beacon signals via the communication IF 22. The communication IF 22 receives a radio tag from the beacon 10, detects the beacon 10, and measures the received radio wave intensity. The communication unit 212 transmits information about the detected beacon 10 to the server 30. The communication IF 22 may include an antenna for communicating with the beacon 10 and a communication module for communicating with the server 30 via the network 4. The storage unit 23 is realized by, for example, an HDD, an SSD, an EEPROM such as a flash memory, or the like. The storage unit 23 holds a program for executing the process according to the embodiment, various data, and various tables in a readable and writable manner. For example, identification information for identifying the receiver 20 and identification information of the beacon 10 received from the beacon 10 are stored.

[0018] FIG. 6 is a diagram showing an example of a functional block of the server 30. The server 30 is a positioning device that identifies the receiver 20 closest to the beacon 10 (in other words, the position of the beacon 10) based on the radio wave strength of the beacon signal measured by the multiple receivers 20. The server 30 is, for example, a stationary computer, and includes a communication IF 31, a calculation unit 32, and a storage unit 33. The communication IF 31 is a communication module for communicating with the receiver 20 via the network 4. The calculation unit 32 identifies the position of the beacon 10 based on information acquired from the receiver 20, and performs process management, for example, in a factory, based on the position of the beacon 10. The storage unit 33 is, for example, composed of an HDD, an SSD, a flash memory, etc. The storage unit 43 holds a program for executing the process according to the embodiment, various data, and various tables in a readable and writable manner. For example, the identification information of the receiver 20 and the identification information of the beacon 10 detected by the receiver 20 are stored in association with each other.

[0019] (Example of operation) FIG. 7 is a diagram for explaining the operation sequence of the system. In the system of this embodiment, the receiver 20 is installed in a factory or the like near a location where a predetermined process is performed. Each receiver 20 is housed in a shield housing 200. The beacon 10 attached to the clear holder 100 is sent together with the object to be processed in the process. The clear holder 100 is housed in the shield housing 200 in each process. The number of beacons 10 and the number of receivers 20 may be multiple. The number of clear holders 100 (in other words, beacons 10) housed in the shield housing 200 may be multiple.

[0020] The beacon 10 continuously broadcasts a radio tag (beacon signal) (FIG. 7: S1). The radio tag includes identification information (beacon ID) of the beacon 10. When the receiver 20 receives the beacon signal, it measures the received radio wave intensity and stores it in the memory unit 23 (FIG. 7: S2). The receiver 20 also transmits information about the detected beacon 10 to the server 30 via the network 4 (FIG. 7: S3). For example, the identification information (receiver ID) of the receiver 20 and the detected beacon ID are transmitted. The received radio wave intensity may also be transmitted. The server 30 receives information about the detected beacon 10 from the receiver 20 and stores it in the memory unit 33. The server 30 also identifies the location of the processing target in the factory based on the information of the beacon 10 detected by the receiver 20, and manages the progress of the process. The server 30 may acquire the received radio wave intensity measured by the receiver 20 and directly identify the receiver 20 closest to the beacon 10 based on the received radio wave intensity, or may transmit information about the beacon 10 that is the transmission source to the server 30 when the receiver 20 detects a beacon signal with a received radio wave intensity equal to or greater than a threshold, and the server 30 may indirectly identify the receiver 20 closest to the beacon 10 based on the received radio wave intensity. For example, the server 30 may output the process in which the detected beacon 10 exists (in other words, the position in the factory) to a user's terminal (not shown) or a monitor provided in the server 30. The server 30 may also adjust the schedule of the work according to the progress of the work. The server 30 may also control the equipment in the factory based on the acquired information.

[0021] (Action, effect) In this embodiment, as shown in FIG. 4, the receiver 20 is housed in a shielded housing 200 that suppresses the transmission of electromagnetic waves. Therefore, the signal from the beacon 10 outside the shielded housing 200 cannot be detected by the receiver 20 in the shielded housing 200, or the received radio wave intensity is reduced. In this way, even when processes in a factory are close to each other, for example, the receiver 20 can accurately identify the signal from the beacon 10 inserted in the same shielded housing 200. That is, the accuracy of position estimation using a beacon can be improved. In addition, the receiver 20 detects the beacon signal that is continuously output using, for example, BLE, so that the timing of the start and end of the process can be accurately detected.

[0022] (Modification) The present invention is not limited to the above-described embodiment, and can be modified or combined without departing from the spirit of the present invention.

[0023] In practice, it is convenient for the shield housing 200 to be relatively small in size, but if it is too small, the expected received signal strength may not be obtained. Specifically, the expected received signal strength cannot be obtained unless a certain length is provided in the horizontal direction (X-axis direction in FIG. 4) and the depth direction (Z-axis direction). In addition, if the top is open, the radio waves may diffract and the intensity difference between inside and outside may not be obtained unless a certain length is provided in the height direction (Y-axis direction). Specifically, the lengths of the shield housing 200 in the horizontal direction (X-axis direction) and the depth direction (Z-axis direction) are preferably half the wavelength of the beacon signal to be transmitted and received. For example, when the radio waves to be transmitted and received use the 2.4 GHz band, the lengths of the horizontal direction (X-axis direction) and the depth direction (Z-axis direction) are preferably about 60 millimeters or more, which is half the wavelength. In addition, an openable lid may be provided at the opening 201 of the shield housing 200 so that the lid can be closed while the positioning target such as the clear holder 100 is accommodated therein.

[0024] Fig. 8 is a diagram for explaining the propagation of electromagnetic waves. When there is a free space formed by two parallel planes of perfect conductors, an electromagnetic wave (dashed line) that enters the free space at an angle θ with the planes propagates by repeatedly reflecting between the two planes. In this case, the wave number of the electromagnetic wave is k 0 Then, the wave number k in the propagation direction g g , wave number k in the direction t perpendicular to the propagation direction t are expressed by the following equations (1) and (2), respectively. k g =k 0 cosθ (1) k t =k 0 sinθ (2) However, a waveguide is formed (i.e., electromagnetic waves propagate) when the condition for a standing wave to occur in the direction t perpendicular to the propagation direction is met. If the distance between the two planes is d, then this can be said to be the case when the following equation (3) is met. k t 2d=2qπ (3) Here, q is the mode number and is a natural number (1, 2, 3, ...). That is, the wavelength λ in the direction t perpendicular to the propagation direction t = 2d / q, q = 1 is the lowest mode in which electromagnetic waves propagate, λ t = 2d. In the lowest mode, the wavelength of the electromagnetic wave, λ 0 As the length of the incident angle θ increases, the incident angle θ and λ when q=1 are 0 The relationship between them can be expressed by the following equation (4). θ=sin -1 (λ 0 / 2d) ···(4) And when θ=π / 2, the wave number k of the electromagnetic wave in the propagation direction g g =0 (i.e. λ g =∞), and electromagnetic waves no longer propagate. Therefore, the cutoff wavelength λ c is expressed by the following equation (5). λ c = λ t(q=1) =2d (5) Therefore, as described above, it is preferable that the length of the shield housing 200 in the depth direction (Z-axis direction) is equal to or greater than half the wavelength of the frequency band used by the beacon signal to be transmitted and received.

[0025] The object to be located, such as the clear holder 100, may have a shape that determines the insertion direction with respect to the shielded housing 200, and the beacon 10 and the receiver 20 may be installed in the clear holder 100 and the shielded housing 200, respectively, so that the polarization planes of the antennas of the beacon 10 and the receiver 20 are aligned with each other. For example, the thickness in the depth direction of the clear holder 100 (the short side of the cross section perpendicular to the insertion direction, the length in the Z-axis direction in FIG. 2) is smaller than the short side of the opening 201 of the shielded housing 200, and the width of the clear holder 100 (the long side of the cross section perpendicular to the insertion direction, the length in the X-axis direction in FIG. 2) is smaller than the long side of the opening 201 of the shielded housing 200. In addition, when the clear holder 100 has a structure in which one of the short sides and one of the long sides are not joined, the user generally inserts the clear holder 100 into the shielded housing 200 in a direction in which the joined side is located downward so that the sandwiched document 101 does not fall. In this way, by appropriately adjusting the position and orientation at which the beacon 10 is attached to the clear holder 100, and the position and orientation at which the receiver 20 is placed within the shielded housing 200, the polarization planes of the antennas can be aligned, thereby ensuring sufficient received radio wave strength.

[0026] The system shown in the embodiment may be used not only for process management within a factory, but also for managing procedures in which the order of steps is not set, such as a medical checkup, or for positioning in other situations.

[0027] A program for making a computer or other machine or device (hereinafter, computer, etc.) realize any of the above functions can be recorded on a computer-readable recording medium. Then, the computer, etc. can provide the function by reading and executing the program from the recording medium. Here, a computer-readable recording medium refers to a recording medium that can store information such as data and programs by electrical, magnetic, optical, mechanical, or chemical action and can be read by a computer, etc. Elements that constitute a computer, such as a CPU and memory, may be provided in such a recording medium, and the CPU may be made to execute the program. Among such recording media, examples of those that can be removed from a computer, etc. include flexible disks, magneto-optical disks, CD-ROMs, CD-R / Ws, DVDs, DATs, 8mm tapes, memory cards, etc. Furthermore, examples of recording media that are fixed to a computer, etc. include hard disks and ROMs.

[0028] (Example) FIG. 9 is a top view for explaining the configuration of a test in the case where the shielded housings are adjacent to each other. In the example of FIG. 9, two shielded housings 200A and 200B are arranged adjacent to each other. Inside the shielded housing 200A, a receiver 20A is attached to the back surface. Similarly, inside the shielded housing 200B, a receiver 20B is attached to the back surface. In addition, ten clear holders 100A are inserted into the shielded housing 200A, and ten clear holders 100B are inserted into the shielded housing 200B. Beacons 10A and 10B are attached to the clear holders 100A and 100B, respectively. In this way, the reception strength from the beacon 10 in the same housing was measured, and the clear holders 100A and 100B were inserted upside down to measure the reception strength from a total of 20 beacons 10 in the same housing. In addition, the reception strength in adjacent housings was measured, and the results were as follows. [Table 1] In No.1, the average reception strength of each beacon in the same shielded housing 200A and 200B was calculated over a certain period (approximately 8,000 pieces of data with a transmission interval of 10 seconds). The average, maximum, and minimum values ​​from the 20 beacons were as shown above. Similarly, the average reception strength from each beacon was measured for the receiver in the other shielded housing. And the maximum value of the 20 beacons was as shown above. No. 2 shows the results when the receivers 20A and 20B are swapped and the average reception strength is measured. No. 3 shows the results of measuring the average reception strength when the shielded housing 200A was replaced with another housing of the same type. No. 4 is a result of measuring the average reception strength when the positions of the receivers 20A and 20B in the shielded housings 200A and 200B are changed from positions in contact with the rear surface to the center in the depth direction (Z-axis direction). Furthermore, when measurements were taken with the shield housings 200A and 200B swapped in the depth direction, the difference in reception strength from each beacon in the same housing was less than 1 dB (referred to as No. 5). From the above results, it can be said that accurate positioning of beacons is possible even when shielded housings are placed adjacent to each other (see Nos. 1 to 5). In addition, the reception strength tended to be about 2 to 3 dB higher with shielded housing 200A than with shielded housing 200B (see Nos. 1 to 5). Even when shielded housing 200A was replaced, the tendency for reception strength was roughly the same (see No. 3). In addition, it can be said that it is preferable to position the receiver in the shielded housing away from the peripheral wall surface (the bottom surface of the receiver is attached to the bottom surface of the shielded housing) rather than contacting the back surface, because this increases the reception strength from beacons in the same housing and decreases the reception strength in adjacent housings (see No. 4).

[0029] FIG. 10 is a top view for explaining the configuration of a test in which a beacon is located outside a shielded housing. A receiver 20 is disposed inside a shielded housing 200. Fifteen beacons 10 are disposed around the shielded housing 200. The beacons 10A to 10N are placed on the same plane as the shielded housing 200. The beacon 10P is disposed 10 cm away below the shielded housing 200. As shown by the thick dashed line, a cable for feeding power to the receiver 20 is wired passing between the beacon A and the beacon N. The rectangular parallelepiped beacon 10 was placed vertically with its longitudinal direction facing vertically and flatly with its longitudinal direction facing horizontally, and was rotated on the spot so that a predetermined surface faces in different directions by 90 degrees each to measure the reception intensity for a certain period of time, with the following results. [Table 2] The maximum values ​​were relatively high for beacons A and N, which were located within 10 cm of the power cable. However, even if the positioning threshold is set to -55 dBm, it is understood that the positioning result will not be determined to be inside the shielded housing 200 if the beacon 10 is 10 cm or more away from the shielded housing 200 and the power cable.

[0030] 11 is a perspective view for explaining a test configuration when the plastic housing 300 is disposed between two shield housings 200A and 200B. The receivers 20A and 20B are disposed inside the two shield housings 200A and 200B, respectively. The shield housing 200A, the plastic housing 300, and the shield housing 200B, each of which is a rectangular parallelepiped, are hung on a wall adjacent to each other in the longitudinal direction (X-axis direction). In addition, a clear holder 100 with a beacon 10 attached thereto was inserted inside the plastic housing 300 and the shield housing 200B, and the reception strength of the receivers 20A and 20B was measured, with the following results. [Table 3] For each beacon 10, the front and back of the clear holder 100 were changed and the average value for a certain period was calculated by 200, and the average value was as described above. Beacons 10A to 10F are beacons attached to the clear holder 100 inserted in the shield housing 200B. Beacons 10G to 10L are beacons attached to the clear holder 100 inserted in the plastic housing 300. It is understood that the receiver 20B located in the same housing can detect the beacons A to F located in the shield housing 200B with high reception intensity. It is also understood that the receiver 20A in the shield housing 200A or the receiver 20B in the shield housing 200B will not detect the beacon 10 in the adjacent plastic housing 300. [Explanation of symbols]

[0031] 10: Beacon 100: Clear holder (positioning object) 20: Receiver 200: Shielded housing 201: Opening 30: Server (positioning device)

Claims

1. a receiver that receives a beacon signal transmitted by the beacon transmitter and measures radio wave intensity; a shielding housing that houses the receiver and suppresses transmission of electromagnetic waves; A plurality of combinations of a positioning device that identifies a receiver that is closest to the beacon transmitter based on the radio field strength measured by each of the receivers; Each of the receivers communicates with a beacon transmitter housed within a shielded enclosure that houses the receiver. Positioning system.

2. The shielding housing is a rectangular parallelepiped having an opening on one side. The beacon transmitter is attached in a predetermined orientation to a positioning object having a shape that determines an insertion direction with respect to the shield housing, The receiver is disposed in the shielded housing such that the polarization plane of the receiver's antenna coincides with the polarization plane of the antenna of a beacon transmitter that is inserted into the shielded housing together with the object to be located. The positioning system according to claim 1 .

3. The shielding housing is a rectangular parallelepiped having an opening on one side. The beacon transmitter is attached in a predetermined orientation to a positioning object having a shape that determines an insertion direction with respect to the shield housing, a short side of a cross section of the object to be positioned perpendicular to the insertion direction is smaller than a short side of the opening of the shield housing, and a long side of the cross section is smaller than a long side of the opening, The short side of the cross section of the shield housing perpendicular to the insertion direction is equal to or larger than half the wavelength of the frequency band used by the beacon signal. The positioning system according to claim 1 .

4. A positioning method in which a computer identifies a receiver that is closest to a beacon transmitter based on radio wave intensity measured by a receiver that receives a beacon signal transmitted from the beacon transmitter, comprising: The receiver is housed in a shielded housing that suppresses the transmission of electromagnetic waves, and communicates with a beacon transmitter that is received in the shielded housing that houses the receiver. Positioning method.

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