WO2020250437A1 - Position detection system for wireless tag - Google Patents

Position detection system for wireless tag Download PDF

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Publication number
WO2020250437A1
WO2020250437A1 PCT/JP2019/023723 JP2019023723W WO2020250437A1 WO 2020250437 A1 WO2020250437 A1 WO 2020250437A1 JP 2019023723 W JP2019023723 W JP 2019023723W WO 2020250437 A1 WO2020250437 A1 WO 2020250437A1
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WO
WIPO (PCT)
Prior art keywords
antenna
wireless tag
antennas
area
radio wave
Prior art date
Application number
PCT/JP2019/023723
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French (fr)
Japanese (ja)
Inventor
輝夫 関
Original Assignee
三菱電機株式会社
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
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Publication date
Application filed by 三菱電機株式会社 filed Critical 三菱電機株式会社
Priority to PCT/JP2019/023723 priority Critical patent/WO2020250437A1/en
Priority to JP2021525883A priority patent/JP7184187B2/en
Publication of WO2020250437A1 publication Critical patent/WO2020250437A1/en

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    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01S—RADIO DIRECTION-FINDING; RADIO NAVIGATION; DETERMINING DISTANCE OR VELOCITY BY USE OF RADIO WAVES; LOCATING OR PRESENCE-DETECTING BY USE OF THE REFLECTION OR RERADIATION OF RADIO WAVES; ANALOGOUS ARRANGEMENTS USING OTHER WAVES
    • G01S11/00—Systems for determining distance or velocity not using reflection or reradiation
    • G01S11/02—Systems for determining distance or velocity not using reflection or reradiation using radio waves
    • G01S11/06—Systems for determining distance or velocity not using reflection or reradiation using radio waves using intensity measurements
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01S—RADIO DIRECTION-FINDING; RADIO NAVIGATION; DETERMINING DISTANCE OR VELOCITY BY USE OF RADIO WAVES; LOCATING OR PRESENCE-DETECTING BY USE OF THE REFLECTION OR RERADIATION OF RADIO WAVES; ANALOGOUS ARRANGEMENTS USING OTHER WAVES
    • G01S5/00—Position-fixing by co-ordinating two or more direction or position line determinations; Position-fixing by co-ordinating two or more distance determinations
    • G01S5/02—Position-fixing by co-ordinating two or more direction or position line determinations; Position-fixing by co-ordinating two or more distance determinations using radio waves
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02D—CLIMATE CHANGE MITIGATION TECHNOLOGIES IN INFORMATION AND COMMUNICATION TECHNOLOGIES [ICT], I.E. INFORMATION AND COMMUNICATION TECHNOLOGIES AIMING AT THE REDUCTION OF THEIR OWN ENERGY USE
    • Y02D30/00—Reducing energy consumption in communication networks
    • Y02D30/70—Reducing energy consumption in communication networks in wireless communication networks

Definitions

  • the present invention relates to a wireless tag position detection system.
  • a pulse signal is transmitted from one installed antenna, a response signal from another installed antenna or a wireless tag to this pulse signal is received, and the time from transmission of the pulse signal to reception of the response signal is set.
  • a position detection system that identifies the distance between the installed antennas, the distance between the installed antenna and the wireless tag, and the current position of the wireless tag by converting to a distance is described.
  • the installed antennas are on the same plane and It is assumed that the wireless tags are on the same plane.
  • the wireless tag fluctuates due to the movement of the object on which the wireless tag is installed.
  • the installation position of the antenna is subject to various restrictions due to the structure and the like, it is extremely difficult to install the antenna according to the same design value.
  • the method of detecting the position of the wireless tag as in the above-mentioned prior art is affected by the variation in the installation position of the antenna and the current height of the wireless tag, and thus is improved in the accuracy of specifying the position of the wireless tag. There is still room for.
  • a method of calculating the distance between the installed antenna and the wireless tag by converting the distance between the installed antenna and the wireless tag is known.
  • the calculation algorithm for converting the radio wave reception intensity into the distance is unique to the antenna model, and it is necessary to change the calculation algorithm every time the antenna model is changed.
  • the replacement work may become complicated and the cost may increase.
  • the present invention has been made to solve the above-mentioned problems, and can easily cope with the replacement of antenna models, and can detect the position of the wireless tag with high accuracy even when the antenna installation height varies. It provides an improved wireless tag position detection system so that it can be used.
  • the position detection system of the wireless tag of the present invention is a position detection system that detects the position of the wireless tag, and includes a wireless tag that can be carried and moved, and a plurality of antennas that communicate with the wireless tag.
  • Each of the plurality of antennas is arranged so that a part of the communication area with the wireless tag overlaps with a part of the communication area between the wireless tag and at least one other antenna.
  • Each of the antennas and the other antennas have a function of transmitting radio waves at intermittent timings that do not interfere with each other.
  • the wireless tag receives the radio wave transmitted from the antenna and measures the radio wave reception intensity, and identifies the antenna that transmits the radio wave having the highest radio wave reception intensity as the corresponding antenna that is the closest antenna to the wireless tag. Furthermore, by comparing the radio wave reception intensity of the radio wave from the corresponding antenna with the first threshold value, whether the position of the wireless tag is in the vicinity area within a certain range from the corresponding antenna in the communication area of the corresponding antenna. Identify if it is in a remote area outside the near area.
  • a wireless tag is a wireless tag position detection system that is configured to send a response to the location of a specified wireless tag to a compatible antenna.
  • the present invention by specifying the corresponding antenna based on the radio wave reception intensity from the antenna, it is possible to specify which antenna the wireless tag is in the identification area. Further, it is not necessary to convert the radio wave reception intensity into a distance, and by comparing with the first threshold value, the position near or far from the corresponding antenna of the wireless tag can be specified with some accuracy.
  • the influence of the variation in the heights of the antennas can be suppressed by adjusting the first threshold value to an appropriate value, and the area near the corresponding antenna can be suppressed. It is possible to accurately identify whether it is in a remote area or in a remote area.
  • FIG. 1 is a diagram schematically showing the configuration of the position detection system of the first embodiment.
  • the position detection system has two antennas 10 and a wireless tag 11 to be positioned.
  • two antennas 10 are shown in FIG. 1, the number of antennas 10 installed is not limited to two.
  • Each antenna 10 is assigned an antenna number.
  • the number of one antenna 10 is number 1
  • the number of the other antenna 10 adjacent to the number 1 antenna 10 is number 2.
  • Each antenna 10 and the antenna 10 adjacent to each antenna 10 are adjusted and set so that a part of each other's radio wave output range overlaps. That is, a part of the communication area 20 between the one antenna 10 and the wireless tag 11 overlaps with a part of the communication area 20 between the other antenna 10 and the wireless tag 11.
  • an identification area 31 for detecting the position of the wireless tag 11 is set and stored in association with each of the antennas 10.
  • the identification area 31 is an area inside the communication area 20, and is set so as not to include a portion closer to the other antenna 10 among the portions not overlapping with the other antenna 10. That is, the identification area 31 is an area set in the communication area 20 of each antenna 10 and in the area on the side of each antenna 10 with respect to the surface intersecting the communication area 20 of the other antennas.
  • each antenna 10 controls the radio wave transmission timing and intermittently transmits radio waves in order to prevent radio wave interference between the antennas 10.
  • the antennas 10 that are adjacent to each other and have overlapping communication areas 20 are registered as an "antenna set" that must not transmit radio waves at the same time, and the radio wave transmission order is assigned in the antenna set. ing.
  • the number of antennas 10 constituting the antenna set is not limited, and may be appropriately set so as to prevent radio wave interference.
  • the wireless tag 11 is attached to an object that is carried or moved by a person, and moves with the person or the object.
  • the wireless tag 11 receives radio waves from the antenna 10 when it is within the communication area 20 of each antenna 10. Further, the wireless tag 11 has a function of measuring the radio wave reception intensity from each antenna 10 (hereinafter, also referred to as “RSSI”.
  • RSSI is an abbreviation for Received Signal Strength Indicator).
  • the wireless tag 11 uses these functions to specify the antenna 10 closest to its current position as the corresponding antenna, and is constant from the corresponding antenna 10 in the identification area 31 of the corresponding antenna 10. It has a position determination function for calculating whether it is in the near area 32 within the range or in the remote area 33 outside the near area 32.
  • the communication area 20, the vicinity area 32, and the remote area 33 are represented by a circle as shown in FIG. 1 as a bird's-eye view, but in reality, a spherical shape or a part centered on each antenna 10 is missing. It is a region formed as a spherical shape.
  • the identification area 31 is represented by a square, it is actually an area in the cube that is in contact with the communication area 20.
  • FIG. 2 is a flowchart showing the operation of position determination by the wireless tag 11.
  • the function of position determination by the wireless tag 11 is realized.
  • the flowchart of FIG. 2 is repeatedly executed at regular intervals.
  • step S100 of FIG. 2 it is determined whether or not there is radio wave reception from each antenna 10. If it is determined in step S100 that no radio wave is received, then in step S101, the position determination of "no corresponding antenna" is made, and this process ends.
  • step S101 determines whether radio waves have been received. If it is determined in step S101 that radio waves have been received, the passage of time is set in step S110, and the counting of the elapsed time is started. Next, in step S111, the antenna number of the antenna that transmitted the received radio wave is stored. Next, in step S112, the RSSI of the received radio wave is measured and stored together with the corresponding antenna number.
  • step S113 it is determined whether or not the designated time has elapsed.
  • This designated time is set to at least a time longer than the time when the radio wave transmission of all the antennas 10 constituting the antenna set is completed. If it is determined in step S113 that the designated time has not elapsed, the process returns to step S110, and the processes of steps S110 to S113 are repeatedly executed until it is determined that the designated time has elapsed. As a result, it is confirmed whether or not the radio wave that may be received at the current position is received, and the antenna number is specified and the RSSI is measured and stored for all the received radio waves.
  • step S113 If it is determined in step S113 that the specified time has elapsed, the process proceeds to step S114, the passage of time is first cleared, and the value of the elapsed time counter is returned to zero.
  • the process proceeds to step S115, the received RSSI is compared, and the corresponding antenna 10 is specified. That is, the antenna 10 closest to the current wireless tag 11 is specified. Specifically, when there is only one received radio wave, the antenna 10 that transmits the radio wave is specified as the corresponding antenna 10. When there are a plurality of received radio waves, the antenna 10 that transmits the radio wave having the maximum RSSI value is specified as the corresponding antenna 10. However, when a plurality of radio waves indicating the maximum RSSI value are received, the antenna 10 having the smallest antenna number among the antennas 10 that transmit the radio waves is specified as the corresponding antenna 10. The configuration is not limited to this, and conversely, the antenna 10 having the highest antenna number may be specified as the corresponding antenna 10.
  • the process proceeds to step S116, and it is determined whether or not the RSSI of the corresponding antenna 10 is larger than the first threshold value.
  • the first threshold value is a reference value previously held by the wireless tag 11 in order to determine whether the identification area 31 of each antenna 10 is a near area 32 close to the antenna 10 or a remote area 33. ..
  • step S116 When it is determined in step S116 that the RSSI of the corresponding antenna 10 is larger than the first threshold value, the radio tag 11 is in the vicinity region 32 in the identification region 31 of the corresponding antenna 10 in the position determination in step S120. Is determined. After that, in step S121, the antenna number of the corresponding antenna 10 which is the result of the position determination and the signal indicating the vicinity are transmitted to the corresponding antenna 10. After that, this process ends.
  • step S116 when it is determined in step S116 that the RSSI of the corresponding antenna is equal to or less than the first threshold value, in the position determination in step S122, the wireless tag 11 is outside the neighborhood area 32 of the identification area 31 of the corresponding antenna 10. That is, it is determined that the remote area 33 is located. After that, in step S121, the antenna number of the corresponding antenna 10 which is the result of the position determination and the signal indicating the remoteness are transmitted to the corresponding antenna 10. After that, this process ends.
  • an identification area 31 for detecting the position of the wireless tag 11 is set and stored in association with each of the antennas 10. Further, the control unit stores the near area 32 and the remote area 33. Therefore, the position detection system identifies the position of the wireless tag 11 according to the received signal by the corresponding antenna 10 receiving the antenna number of the corresponding antenna 10 and a signal of near or remote from the wireless tag 11. can do.
  • the wireless tag 11 can be used by associating the boundary position between the near region 32 and the remote region 33 for each antenna with respect to the first threshold value. It is possible to accurately identify the position in the identification area 31 of the corresponding antenna 10 to some extent. Normally, it is difficult to make the intervals and heights of the installed antennas the same or according to the design values, but in the position detection system of the present embodiment, the first threshold value is adjusted after the antennas are installed. Can be handled with.
  • the position detection system of the present embodiment the position can be determined by dividing one antenna into two divided areas. Therefore, the position can be specified more finely with a small number of antennas installed.
  • FIG. 3 is a diagram schematically showing the configuration of the position detection system according to the second embodiment.
  • the position detection system of the second embodiment has the same configuration as the position detection system of FIG.
  • the position detection system of the second embodiment further divides the remote area 33 into two divided areas, an area x_x on the corresponding antenna 10 side and an area x_y on the proximity antenna side, for a total of 3
  • the position can be specified by two divided areas.
  • x represents a number indicating the antenna number of the specified corresponding antenna 10
  • y indicates the corresponding antenna 10 and the antenna set. It shall represent a number indicating the antenna number of the constituent antenna.
  • the antenna 10 that constitutes an antenna set together with a certain antenna 10 is referred to as a "proximity antenna”.
  • the wireless tag 11 records a second threshold value in addition to the first threshold value.
  • the wireless tag 11 determines which division area in the remote area 33 is located by comparing the RSSI of the received radio wave with the second threshold value.
  • the second threshold value is at least a value smaller than the first threshold value.
  • the specific value of the second threshold value is set according to the intensity of the radio wave received from the proximity antenna 10. By adjusting the second threshold value, the boundary line between the area x_x on the corresponding antenna 10 side and the area x_y on the neighboring antenna side is adjusted.
  • the position determination by the wireless tag 11 of the second embodiment will be specifically described.
  • FIG. 4 is a flowchart showing the operation of position determination by the wireless tag 11.
  • the flowchart of FIG. 4 is the same as that of FIG. 2 except that the processing of steps S201 to S203 is performed instead of the processing of step S122.
  • the process of steps S100 to S121, which is the same as the flowchart of FIG. 2, will not be described.
  • step S116 when it is determined in step S116 that the RSSI of the radio wave from the corresponding antenna 10 is equal to or less than the first threshold value, the wireless tag 11 proceeds to step S201 and then proceeds to the wireless tag.
  • the wireless tag 11 Among the radio waves received by 11, it is determined whether or not the number of received radio waves whose RSSI exceeds the second threshold value is 1.
  • step S201 If it is determined in step S201 that the number of received radio waves exceeding the second threshold value is 1, it can be determined that radio waves having an intensity exceeding the second threshold value are received only from the corresponding antenna 10. In this case, the process proceeds to step S202, the position is determined as the remote area x_x on the corresponding antenna 10 side, the process proceeds to step S121, and the position determination result is notified.
  • step S201 when it is determined in step S201 that the number of receptions is not 1, the number of receptions is 2, and it is said that radio waves having an intensity exceeding the second threshold value are received from the corresponding antenna 10 and the neighboring antenna 10. I can judge. In this case, the process proceeds to step S203, and after the position is determined as the remote area x_y on the neighboring antenna 10 side, the process proceeds to step S121, and the position determination result is notified to the corresponding antenna 10.
  • the control unit of the position detection system stores the near area 32 and the remote area 33. Further, by adjusting the second threshold value, the boundaries of the divided areas x_x and x_y of the remote area 33 are adjusted, and the control unit of the position detection system stores the divided areas x_x and x_y in each of the identification areas 31. There is. Therefore, when it is determined that the wireless tag 11 is in the remote region 33 of the corresponding antenna 10, the control unit of the position detection system wirelessly receives the signal of "x_x" or "x_y" received by the corresponding antenna 10. The position of the tag 11 can be detected.
  • the position detection area of the corresponding antenna 10 is further subdivided by comparing the reception intensities of the radio waves transmitted from the corresponding antenna 10 and the neighboring antenna 10. be able to. Further, even when the intervals and heights of the antennas 10 to be installed vary, the positions can be accurately specified by adjusting the first threshold value and the second threshold value after the antenna 10 is installed.
  • each antenna 10 and the other two proximity antennas 10 whose communication areas 20 partially overlap are registered as an antenna set.
  • the remote area 33 of the identification area 31 associated with the antenna 10 sandwiched between the two neighboring antennas 10 has a remote area x_y1 close to the one neighboring antenna 10 having an antenna number of y1 and an antenna number of y2.
  • the position information is detected by being divided into three divided areas of a remote area x_y2 close to the other neighboring antenna 10 and a remote area x_x close to the corresponding antenna 10 in between.
  • Specific position identification when there are three antenna sets can be executed by the process shown in FIG. That is, when it is determined in step S201 of FIG. 4 that the number of received radio waves exceeding the second threshold value is 2 or more, the antenna number of the neighboring antenna 10 that has transmitted the radio wave exceeding the second threshold value in the process of step S203.
  • y it is specified that the user is in the area x_y in the remote area.
  • FIG. 5 is a diagram schematically showing the configuration of the position detection system according to the third embodiment.
  • the four antennas 10 of Nos. 1 to 4 are installed adjacent to each other.
  • Each of the four antennas 10 is installed so that a part of the communication area 20 with the wireless tag 11 overlaps with a part of the communication area 20 between the other three antennas 10 and the wireless tag 11.
  • These four antennas 10 are registered as an antenna set.
  • the identification area 31 corresponding to the antenna 10 of the number x is divided into a near area 32 and a remote area 33, and the position is determined.
  • the remote area 33 includes an area in which radio waves having an intensity exceeding the second threshold value are not received from any neighboring antenna 10 and an area in which radio waves having an intensity exceeding the second threshold value are received from one of the other neighboring antennas 10.
  • the position is determined by dividing into four areas, one is an area for receiving radio waves having an intensity exceeding the second threshold value from the other two or more neighboring antennas 10.
  • the four areas are specified by the antenna number x of the corresponding antenna 10 and the antenna number y of the neighboring antenna 10. Specifically, when a radio wave having an intensity exceeding the second threshold value is not received from the proximity antenna 10 other than the corresponding antenna 10, the antenna number x_x of the corresponding antenna 10 is transmitted to specify the area. For example, when the corresponding antenna 10 is the antenna of the antenna number 1, the area 1-11 of FIG. 5 is an area specified when a radio wave having an intensity exceeding the second threshold value is not received from the proximity antenna 10 other than the corresponding antenna 10. is there.
  • the antenna number x of the corresponding antenna 10 and the antenna number y of the proximity antenna that has transmitted the radio wave having an intensity exceeding the second threshold value are transmitted.
  • the area is specified.
  • the area specified when the corresponding antenna 10 is the antenna number 1 and the radio wave exceeding the second threshold value is received from the proximity antenna 10 of the antenna number 4 is the area 1_4 in FIG.
  • the radio tag 11 When radio waves having a strength exceeding the second threshold value are received from two or more of the proximity antennas 10, the radio tag 11 is in an area where the communication areas 20 of the three or all antennas overlap. This area is specified by the antenna number x of the corresponding antenna 10 and the antenna number z of the proximity antenna 10 arranged diagonally of the corresponding antenna 10. For example, the area specified when the corresponding antenna 10 has the antenna number 1 and receives radio waves exceeding the second threshold value from two or more proximity antennas is the area 1_3 of FIG.
  • the diagonal antenna number z for each antenna 10 may be stored in advance in the wireless tag 11. Further, instead of transmitting the antenna number, some signal z may be transmitted as x_z as a signal indicating that the three or more communication areas 20 are in the overlapping area.
  • the control unit of the position detection system stores each position corresponding to the signal "x_x” or "x_y” or “x_z” indicating the area in the remote area 33 transmitted from the wireless tag 11. Therefore, the radio tag 11 can identify the position in the control unit by transmitting these signals indicating the area in the remote area 33.
  • FIG. 6 is a flowchart showing the operation of position determination by the wireless tag 11.
  • the flowchart of FIG. 6 is the same as the flowchart of FIG. 4 except that the processing of steps S301 to S306 is performed instead of the processing of steps S201 to S203.
  • the description of the process of steps S100 to S121 which is the same as that of FIG. 2 or 4 will be omitted.
  • step S116 if it is determined in step S116 that the RSSI of the radio wave from the corresponding antenna 10 is equal to or less than the first threshold value, the process proceeds to step S301, and the intensity of the RSSI exceeds the second threshold value. The number of received radio waves is confirmed. As a result of the confirmation, if the number of receptions is 1, it is determined that the received radio wave is the radio wave transmitted from the corresponding antenna 10. In this case, the process proceeds to step S302, and it is determined that the remote area 33 is in the area x_x that receives radio waves of the second threshold value or more from only the corresponding antenna 10. After that, the process proceeds to step S121, and as a result of the position determination, the signal x_x is notified to the corresponding antenna 10.
  • step S301 If it is determined in step S301 that the number of received radio waves having an intensity exceeding the second threshold value is 2, the process proceeds to step S303, and the number of the proximity antenna 10 that transmits the radio waves having an intensity exceeding the second threshold value. y is stored. Next, the process proceeds to the position determination in step S304, and it is determined that the area "x_y" is located. After that, the process proceeds to step S121, and as a result of the position determination, the signal x_y is notified to the corresponding antenna 10.
  • step S301 If it is determined in step S301 that the number of received radio waves having an intensity exceeding the second threshold value is 3 or more, the process proceeds to step S305, and the antenna number z located diagonally with respect to the corresponding antenna 10 is It will be remembered. Next, the process proceeds to the position determination in step S306, and it is determined that the antenna number x of the corresponding antenna 10 is in the area “x_z” specified by the antenna number z at the diagonal position. After that, the process proceeds to step S121, and as a result of the position determination, the signal x_z is notified to the corresponding antenna 10.
  • the area for one antenna can be divided into five areas and the position information can be detected.
  • more detailed position detection can be performed without increasing the number of installed antennas.
  • the positions can be accurately specified by adjusting the first threshold value and the second threshold value after the antenna 10 is installed.
  • the position information detection of one region corresponding to one antenna set including four antennas has been illustrated and described, but the present embodiment is not limited to this, and the figure is shown in the figure. As shown in 7, a set of four antennas and a plurality of regions corresponding to the antenna sets may be arranged side by side. Also in this case, when the wireless tag 11 is in the remote area 33, it is possible to specify where in each of the four divided areas of the remote area 33 by the flowchart of FIG.
  • the position detection system of the present embodiment specifies the position with four antennas as one set, it is desirable that the number of antennas to be installed is a multiple of 4. However, it is possible to apply this even if it is not a multiple of 4.
  • FIG. 8 shows an example in which the number of antennas 10 is six. If the number of antennas is not a multiple of 4, some antennas may be duplicated in the two antenna sets so that they are a multiple of 4. For example, in the example of FIG. 8, the antennas No. 2 and No. 3 arranged in the central row are overlapped in the two antenna sets 40 and 41. Thereby, the remote area 33 can be divided into four divided areas for each corresponding antenna 10 and the position information can be acquired by the same method as shown in the flowchart of FIG.
  • the wireless tag 11 can detect the position information by the same processing as the flowchart of FIG.
  • the number of divisible areas decreases as the number of adjacent antennas decreases.
  • the antenna No. 4 is insufficient with respect to the configuration example of the third embodiment shown in FIG.
  • the area 1_4 when the corresponding antenna 10 specified by the radio wave from the fourth antenna 10 is No. 1
  • the area 3_4 when the corresponding antenna 10 is No. 3 cannot be specified, respectively.
  • the area where the communication area 20 does not overlap with the other proximity antennas 10 due to the lack of the proximity antenna 10 in the control unit of the position detection system is defined as the area x_x of each of the corresponding antennas 10.
  • the number of antennas constituting the antenna set is two.
  • the position information can be detected by executing the same process as the flowchart of FIG.
  • the number of received radio waves stronger than the second threshold value is either 1 or 2
  • the processes of steps S305 to S306 are not executed.
  • the divided area of the remote area 33 of the corresponding antenna 10 is either x_y close to the proximity antenna 10 or an area x_x far from the proximity antenna 10.
  • the identification area 31 of each antenna 10 can be divided into an area of the number of antennas constituting the antenna set + 1 and the position information can be detected.
  • the number of antennas in the antenna set is preferably 4 or less.
  • the control unit of the position detection system of the first to third embodiments may be mounted on each of the antennas 10, or may be connected to any of the antennas 10 or 10 in a state of being able to communicate with all the antennas 10. May be mounted on a device installed at another location.
  • the wireless tag 11 identifies the corresponding antenna 10 and determines the position and transmits the result to the corresponding antenna 10
  • the antenna 10 may be provided with the same position determination function.
  • the wireless tag 11 identifies the corresponding antenna 10, transmits the RSSI value of the received radio wave to the corresponding antenna 10, and displays the RSSI on the corresponding antenna 10 side or a separately installed control unit.
  • the position of the radio tag 11 may be specified by executing the comparison with the first threshold value and the comparison with the second threshold value.
  • the identification area 31 is not limited to this, and for example, among the communication areas 20 of each antenna 10, all the areas on the antenna 10 side of the surface intersecting the other communication areas 20 are identified corresponding to the antenna 10. It may be configured to be registered as an area.
  • the configuration in which the result of the position determination is transmitted only to the corresponding antenna 10 has been described.
  • the antennas to be transmitted in this way to the corresponding antennas 10 power consumption can be reduced.
  • the present invention is not limited to this configuration, and for example, the position determination result may be transmitted to all the antennas 10 constituting the antenna set.

Abstract

This position detection system for a wireless tag (11) is provided with a wireless tag (11) and a plurality of antennas (10). Each of the antennas (10) is arranged with the other antennas (10) so that communication areas (20) with the wireless tag (11) partially overlap with each other. Each antenna (10) performs radio wave transmission at a timing that does not result in radio wave interference with the other antennas (10). The wireless tag (11) receives radio waves from the antennas (10), measures RSSIs which are the reception strengths of the radio waves, and specifies an antenna (10) that transmitted a radio wave having the largest RSSI as the corresponding antenna (10) closest to the wireless tag (11). In addition, the wireless tag (11) compares the RSSI of the radio wave of the corresponding antenna (10) and a first threshold value and thereby specifies whether the position of said wireless tag (11) is in an area (32) near the corresponding antenna (10) or in an area (33) on the exterior of said area (32). The wireless tag (11) transmits the specified position information to the corresponding antenna (10).

Description

無線タグの位置検知システムWireless tag position detection system
　本発明は、無線タグの位置検知システムに関する。 The present invention relates to a wireless tag position detection system.
　日本特許第４６５００５３号には、ある設置アンテナからパルス信号を送信し、このパルス信号に対する他の設置アンテナ又は無線タグからの応答信号を受信し、パルス信号の送信から応答信号の受信までの時間を距離に変換することで、設置アンテナ間の距離、設置アンテナと無線タグ間の距離、及び、無線タグの現在の位置を特定する位置検出システムが記載されている。 According to Japanese Patent No. 4650053, a pulse signal is transmitted from one installed antenna, a response signal from another installed antenna or a wireless tag to this pulse signal is received, and the time from transmission of the pulse signal to reception of the response signal is set. A position detection system that identifies the distance between the installed antennas, the distance between the installed antenna and the wireless tag, and the current position of the wireless tag by converting to a distance is described.
日本特許第４６５００５３号Japanese Patent No. 4650053
　上記の従来の技術のように、パルス信号の送信から応答信号の受信までの時間を距離に変換することで無線タグの位置を検出する方法では、設置アンテナ同士が同一平面上にあり、かつ、無線タグが同一平面状にあることが前提となる。しかしながら、実際には、無線タグは、無線タグが設置された物の移動によって変動する。また、アンテナの設置位置は、構造等による種々の制約を受けるため、高さを同一の設計値通りに設置することは極めて困難である。 In the method of detecting the position of the wireless tag by converting the time from the transmission of the pulse signal to the reception of the response signal into a distance as in the above-mentioned conventional technique, the installed antennas are on the same plane and It is assumed that the wireless tags are on the same plane. However, in reality, the wireless tag fluctuates due to the movement of the object on which the wireless tag is installed. Further, since the installation position of the antenna is subject to various restrictions due to the structure and the like, it is extremely difficult to install the antenna according to the same design value.
　このように上記の従来技術のような無線タグの位置を検出する方法は、アンテナの設置位置や無線タグの現在の高さのばらつきの影響を受けるため、無線タグの位置特定の精度点において改善の余地が残る。 As described above, the method of detecting the position of the wireless tag as in the above-mentioned prior art is affected by the variation in the installation position of the antenna and the current height of the wireless tag, and thus is improved in the accuracy of specifying the position of the wireless tag. There is still room for.
　また、例えば、設置アンテナと無線タグとの間の電波受信強度を距離変換することで、設置アンテナと無線タグとの距離を計算する方法が知られている。しかし、電波受信強度を距離換算する計算アルゴリズムは、アンテナ機種に対して一意であり、アンテナ機種が変わるたびに計算アルゴリズムを変更する必要がある。しかし、アンテナ機種交換時に毎回計算アルゴリズムの変更まで必要となれば、交換作業が複雑化し、また、コストの増大化を招く虞がある。 Further, for example, a method of calculating the distance between the installed antenna and the wireless tag by converting the distance between the installed antenna and the wireless tag is known. However, the calculation algorithm for converting the radio wave reception intensity into the distance is unique to the antenna model, and it is necessary to change the calculation algorithm every time the antenna model is changed. However, if it is necessary to change the calculation algorithm every time the antenna model is replaced, the replacement work may become complicated and the cost may increase.
　本発明は、上述の課題を解決するためになされたもので、アンテナの機種交換にも容易に対応でき、かつ、アンテナ設置高さにばらつきがある場合にも高い精度で無線タグの位置を検出することができるよう改良された無線タグの位置検知システムを提供するものである。 The present invention has been made to solve the above-mentioned problems, and can easily cope with the replacement of antenna models, and can detect the position of the wireless tag with high accuracy even when the antenna installation height varies. It provides an improved wireless tag position detection system so that it can be used.
　本発明の無線タグの位置検知システムは、無線タグの位置を検知する位置検知システムであって、携帯して移動可能な無線タグと、無線タグと通信する複数のアンテナと、を備える。複数のアンテナのそれぞれは、無線タグとの通信領域の一部が、少なくとも１つの他のアンテナと無線タグとの通信領域の一部と重なるように配置されている。アンテナのそれぞれと、他のアンテナとは、互いに電波干渉しない間欠的なタイミングで電波送信する機能を備える。 The position detection system of the wireless tag of the present invention is a position detection system that detects the position of the wireless tag, and includes a wireless tag that can be carried and moved, and a plurality of antennas that communicate with the wireless tag. Each of the plurality of antennas is arranged so that a part of the communication area with the wireless tag overlaps with a part of the communication area between the wireless tag and at least one other antenna. Each of the antennas and the other antennas have a function of transmitting radio waves at intermittent timings that do not interfere with each other.
　無線タグは、アンテナから送信された電波を受信すると共に電波受信強度を測定し、電波受信強度が最も大きい電波を送信したアンテナを、無線タグに最も近いアンテナである対応アンテナとして特定する。更に、対応アンテナからの電波の電波受信強度と第１閾値との比較により、無線タグの位置が、対応アンテナの通信領域のなかの、対応アンテナから一定の範囲内にある近傍領域にあるか、近傍領域の外側の遠隔領域にあるかを特定する。無線タグは、対応アンテナに、特定した無線タグの位置の応答を送信するように構成されている無線タグの位置検知システム。 The wireless tag receives the radio wave transmitted from the antenna and measures the radio wave reception intensity, and identifies the antenna that transmits the radio wave having the highest radio wave reception intensity as the corresponding antenna that is the closest antenna to the wireless tag. Furthermore, by comparing the radio wave reception intensity of the radio wave from the corresponding antenna with the first threshold value, whether the position of the wireless tag is in the vicinity area within a certain range from the corresponding antenna in the communication area of the corresponding antenna. Identify if it is in a remote area outside the near area. A wireless tag is a wireless tag position detection system that is configured to send a response to the location of a specified wireless tag to a compatible antenna.
　本発明によれば、アンテナからの電波受信強度に基づいて対応アンテナが特定されることで、無線タグがどのアンテナの識別領域にあるかを特定することができる。また、電波受信強度を距離換算する必要がなく、第１閾値との比較によって、無線タグの対応アンテナに対し近傍か遠隔かの位置をある程度正確に特定することができる。ここで、複数のアンテナの高さに大きなばらつきがある場合にも、第１閾値を適切な値に調整することで、アンテナの高さのばらつきの影響を抑えることができ、対応アンテナの近傍領域にあるか遠隔領域にあるかを正確に特定することができる。 According to the present invention, by specifying the corresponding antenna based on the radio wave reception intensity from the antenna, it is possible to specify which antenna the wireless tag is in the identification area. Further, it is not necessary to convert the radio wave reception intensity into a distance, and by comparing with the first threshold value, the position near or far from the corresponding antenna of the wireless tag can be specified with some accuracy. Here, even when there is a large variation in the heights of a plurality of antennas, the influence of the variation in the heights of the antennas can be suppressed by adjusting the first threshold value to an appropriate value, and the area near the corresponding antenna can be suppressed. It is possible to accurately identify whether it is in a remote area or in a remote area.
本発明の実施の形態１に係る位置検知システムの構成を模式的に示す図である。It is a figure which shows typically the structure of the position detection system which concerns on Embodiment 1 of this invention. 本発明の実施の形態１に係る無線タグの位置判定の動作を示すフローチャートである。It is a flowchart which shows the operation of the position determination of the wireless tag which concerns on Embodiment 1 of this invention. 本発明の実施の形態２に係る位置検知システムの構成を模式的に示す図である。It is a figure which shows typically the structure of the position detection system which concerns on Embodiment 2 of this invention. 本発明の実施の形態２に係る無線タグの位置判定の動作を示すフローチャートである。It is a flowchart which shows the operation of the position determination of the wireless tag which concerns on Embodiment 2 of this invention. 本発明の実施の形態３に係る位置検知システムの構成を模式的に示す図である。It is a figure which shows typically the structure of the position detection system which concerns on Embodiment 3 of this invention. 本発明の実施の形態３に係る無線タグの位置判定の動作を示すフローチャートである。It is a flowchart which shows the operation of the position determination of the wireless tag which concerns on Embodiment 3 of this invention. 本発明の実施の形態３に係る位置検知システムの他の構成例を模式的に示す図である。It is a figure which shows typically the other structural example of the position detection system which concerns on Embodiment 3 of this invention. 本発明の実施の形態３に係る位置検知システムの他の構成例を模式的に示す図である。It is a figure which shows typically the other structural example of the position detection system which concerns on Embodiment 3 of this invention. 本発明の実施の形態３に係る位置検知システムの他の構成例を模式的に示す図である。It is a figure which shows typically the other structural example of the position detection system which concerns on Embodiment 3 of this invention. 本発明の実施の形態３に係る位置検知システムの他の構成例を模式的に示す図である。It is a figure which shows typically the other structural example of the position detection system which concerns on Embodiment 3 of this invention.
　以下、図面を参照して実施の形態について説明する。各図において共通または対応する要素には、同一の符号を付して、重複する説明を簡略化または省略する。 Hereinafter, embodiments will be described with reference to the drawings. Common or corresponding elements in the drawings are designated by the same reference numerals to simplify or omit duplicate description.
実施の形態１．
　図１は、実施の形態１の位置検知システムの構成を模式的に示す図である。位置検知システムは、２つアンテナ１０と位置検知の対象となる無線タグ１１とを有している。図１には、２つのアンテナ１０が表されているが、アンテナ１０の設置数は２つに限られない。各アンテナ１０には、それぞれアンテナ番号が付されている。ここでは、２つのアンテナ１０のうち、一方のアンテナ１０の番号を１番とし、１番のアンテナ１０に隣接する他のアンテナ１０の番号を２番としている。 Embodiment 1.
FIG. 1 is a diagram schematically showing the configuration of the position detection system of the first embodiment. The position detection system has two antennas 10 and a wireless tag 11 to be positioned. Although two antennas 10 are shown in FIG. 1, the number of antennas 10 installed is not limited to two. Each antenna 10 is assigned an antenna number. Here, of the two antennas 10, the number of one antenna 10 is number 1, and the number of the other antenna 10 adjacent to the number 1 antenna 10 is number 2.
　各アンテナ１０と、それに隣接するアンテナ１０とは、互いの電波出力範囲の一部が重複するように調整され設定されている。即ち、一方のアンテナ１０と無線タグ１１との通信領域２０の一部は、他方のアンテナ１０と無線タグ１１との通信領域２０の一部と重複している。 Each antenna 10 and the antenna 10 adjacent to each antenna 10 are adjusted and set so that a part of each other's radio wave output range overlaps. That is, a part of the communication area 20 between the one antenna 10 and the wireless tag 11 overlaps with a part of the communication area 20 between the other antenna 10 and the wireless tag 11.
　位置検知システムには、各アンテナ１０のそれぞれに対応づけられて、無線タグ１１の位置を検知するための識別領域３１が設定され、記憶されている。識別領域３１は、通信領域２０より内側の領域であり、他のアンテナ１０と重複していない部分のうち他のアンテナ１０のほうが近い部分は含まないように設定されている。つまり、識別領域３１は、各アンテナ１０の通信領域２０内であり、かつ、他のアンテナの通信領域２０と交差する面よりも、各アンテナ１０側の領域内に設定された領域である。 In the position detection system, an identification area 31 for detecting the position of the wireless tag 11 is set and stored in association with each of the antennas 10. The identification area 31 is an area inside the communication area 20, and is set so as not to include a portion closer to the other antenna 10 among the portions not overlapping with the other antenna 10. That is, the identification area 31 is an area set in the communication area 20 of each antenna 10 and in the area on the side of each antenna 10 with respect to the surface intersecting the communication area 20 of the other antennas.
　また、各アンテナ１０は、各アンテナ１０同士の電波干渉を防止するために、電波送信タイミングを制御し、それぞれ間欠的に電波送信を行う。以下、実施の形態１～３において、互いに隣接し通信領域２０が重複するアンテナ１０同士は、同時に電波送信させてはならない「アンテナセット」として登録され、アンテナセットの中で電波送信順序が割り当てられている。なお、アンテナセットを構成するアンテナ１０の台数に制約はなく、電波干渉を防止できるように適宜設定すればよい。 Further, each antenna 10 controls the radio wave transmission timing and intermittently transmits radio waves in order to prevent radio wave interference between the antennas 10. Hereinafter, in the first to third embodiments, the antennas 10 that are adjacent to each other and have overlapping communication areas 20 are registered as an "antenna set" that must not transmit radio waves at the same time, and the radio wave transmission order is assigned in the antenna set. ing. The number of antennas 10 constituting the antenna set is not limited, and may be appropriately set so as to prevent radio wave interference.
　無線タグ１１は、人に携帯され又は移動する物体に取り付けられ、人又は物体とともに移動する。無線タグ１１は、各アンテナ１０の通信領域２０内にあるときに、そのアンテナ１０からの電波を受信する。また、無線タグ１１は、各アンテナ１０からの電波受信強度（以下、「ＲＳＳＩ」とも称する。なお、ＲＳＳＩは、Received Signal Strength Indicatorの略）を測定する機能を有している。 The wireless tag 11 is attached to an object that is carried or moved by a person, and moves with the person or the object. The wireless tag 11 receives radio waves from the antenna 10 when it is within the communication area 20 of each antenna 10. Further, the wireless tag 11 has a function of measuring the radio wave reception intensity from each antenna 10 (hereinafter, also referred to as “RSSI”. RSSI is an abbreviation for Received Signal Strength Indicator).
　更に、無線タグ１１は、これらの機能を用いて、自身の現在の位置に最も近いアンテナ１０を対応アンテナとして特定すると共に、その対応アンテナ１０の識別領域３１のなかで、対応アンテナ１０から一定の範囲内の近傍領域３２にあるか、近傍領域３２より外側の遠隔領域３３にあるかを算出する位置判定の機能を有している。なお、通信領域２０、近傍領域３２、及び、遠隔領域３３は、俯瞰図としては図１のように円形で表されているが、実際には各アンテナ１０を中心とした球状又は一部が欠けた球状として形成される領域である。また、同様に、識別領域３１は、正方形で表されているが、実際には、通信領域２０に接する立方体内の領域である。 Further, the wireless tag 11 uses these functions to specify the antenna 10 closest to its current position as the corresponding antenna, and is constant from the corresponding antenna 10 in the identification area 31 of the corresponding antenna 10. It has a position determination function for calculating whether it is in the near area 32 within the range or in the remote area 33 outside the near area 32. The communication area 20, the vicinity area 32, and the remote area 33 are represented by a circle as shown in FIG. 1 as a bird's-eye view, but in reality, a spherical shape or a part centered on each antenna 10 is missing. It is a region formed as a spherical shape. Similarly, although the identification area 31 is represented by a square, it is actually an area in the cube that is in contact with the communication area 20.
　図２は、無線タグ１１による位置判定の動作を示すフローチャートである。図２のフローチャートが実行されることで、無線タグ１１による位置判定の機能が実現する。以下、図２を用いて、位置判定時の無線タグ１１の具体的な動作について説明する。図２のフローチャートは一定の間隔で繰り返し実行される。 FIG. 2 is a flowchart showing the operation of position determination by the wireless tag 11. By executing the flowchart of FIG. 2, the function of position determination by the wireless tag 11 is realized. Hereinafter, the specific operation of the wireless tag 11 at the time of position determination will be described with reference to FIG. The flowchart of FIG. 2 is repeatedly executed at regular intervals.
　まず、図２のＳ１００では、各アンテナ１０からの電波受信があるか否かが判別される。ステップＳ１００で電波受信なしと判別された場合、次に、ステップＳ１０１では、「対応アンテナなし」の位置判定が成され、今回の処理は終了する。 First, in S100 of FIG. 2, it is determined whether or not there is radio wave reception from each antenna 10. If it is determined in step S100 that no radio wave is received, then in step S101, the position determination of "no corresponding antenna" is made, and this process ends.
　一方、ステップＳ１０１で電波受信ありと判別された場合、ステップＳ１１０で時間経過がセットされ、経過時間のカウントが開始される。次に、ステップＳ１１１で、受信した電波を送信したアンテナのアンテナ番号が記憶される。次に、ステップＳ１１２で、受信した電波のＲＳＳＩが測定され、対応するアンテナ番号と共に記憶される。 On the other hand, if it is determined in step S101 that radio waves have been received, the passage of time is set in step S110, and the counting of the elapsed time is started. Next, in step S111, the antenna number of the antenna that transmitted the received radio wave is stored. Next, in step S112, the RSSI of the received radio wave is measured and stored together with the corresponding antenna number.
　次に、ステップＳ１１３で、指定時間が経過したか否かが判別される。この指定時間は、少なくとも、アンテナセットを構成する全アンテナ１０の電波送信が完了する時間より長い時間に設定される。ステップＳ１１３で指定時間が経過していないと判別された場合には、処理はステップＳ１１０に戻り、指定時間が経過したと判別されるまで、ステップＳ１１０～Ｓ１１３の処理が繰り返し実行される。これにより、現在の位置で受信する可能性がある電波の受信の有無が確認されると共に、受信された全ての電波についてアンテナ番号の特定とＲＳＳＩの計測と記憶とが実行される。 Next, in step S113, it is determined whether or not the designated time has elapsed. This designated time is set to at least a time longer than the time when the radio wave transmission of all the antennas 10 constituting the antenna set is completed. If it is determined in step S113 that the designated time has not elapsed, the process returns to step S110, and the processes of steps S110 to S113 are repeatedly executed until it is determined that the designated time has elapsed. As a result, it is confirmed whether or not the radio wave that may be received at the current position is received, and the antenna number is specified and the RSSI is measured and stored for all the received radio waves.
　ステップＳ１１３で指定時間が経過したと判別された場合には、処理はステップＳ１１４に進み、まず時関経過がクリアされ、経過時間のカウンタの値はゼロに戻される。 If it is determined in step S113 that the specified time has elapsed, the process proceeds to step S114, the passage of time is first cleared, and the value of the elapsed time counter is returned to zero.
　次に、処理はステップＳ１１５に進み、受信したＲＳＳＩが比較され、対応アンテナ１０が特定される。即ち、現在の無線タグ１１に最も近い位置にあるアンテナ１０が特定される。具体的に、受信した電波が１つである場合には、その電波を送信したアンテナ１０が対応アンテナ１０として特定される。受信した電波が複数ある場合、ＲＳＳＩの値が最大の電波を送信したアンテナ１０が対応アンテナ１０として特定される。ただし最大のＲＳＳＩの値を示す電波を複数受信した場合は、その電波を送信したアンテナ１０のうち、アンテナ番号が最も小さいアンテナ１０を対応アンテナ１０として特定することとする。なお、この構成に限られず、逆に最も大きいアンテナ番号のアンテナ１０を対応アンテナ１０として特定する構成としてもよい。 Next, the process proceeds to step S115, the received RSSI is compared, and the corresponding antenna 10 is specified. That is, the antenna 10 closest to the current wireless tag 11 is specified. Specifically, when there is only one received radio wave, the antenna 10 that transmits the radio wave is specified as the corresponding antenna 10. When there are a plurality of received radio waves, the antenna 10 that transmits the radio wave having the maximum RSSI value is specified as the corresponding antenna 10. However, when a plurality of radio waves indicating the maximum RSSI value are received, the antenna 10 having the smallest antenna number among the antennas 10 that transmit the radio waves is specified as the corresponding antenna 10. The configuration is not limited to this, and conversely, the antenna 10 having the highest antenna number may be specified as the corresponding antenna 10.
　次に、ステップＳ１１６に進み、対応アンテナ１０のＲＳＳＩが第１閾値より大きいか否かが判別される。第１閾値は、各アンテナ１０の識別領域３１の中で、そのアンテナ１０に近い近傍領域３２であるか、遠隔領域３３であるかを判定するために予め無線タグ１１が保持する基準値である。 Next, the process proceeds to step S116, and it is determined whether or not the RSSI of the corresponding antenna 10 is larger than the first threshold value. The first threshold value is a reference value previously held by the wireless tag 11 in order to determine whether the identification area 31 of each antenna 10 is a near area 32 close to the antenna 10 or a remote area 33. ..
　ステップＳ１１６で、対応アンテナ１０のＲＳＳＩが第１閾値より大きいと判別された場合は、ステップＳ１２０の位置判定で、無線タグ１１は、対応アンテナ１０の識別領域３１の中の近傍領域３２内にあると判定される。その後、ステップＳ１２１で、位置判定の結果である対応アンテナ１０のアンテナ番号と、近傍を示す信号が、対応アンテナ１０に送信される。その後、今回の処理は終了する。 When it is determined in step S116 that the RSSI of the corresponding antenna 10 is larger than the first threshold value, the radio tag 11 is in the vicinity region 32 in the identification region 31 of the corresponding antenna 10 in the position determination in step S120. Is determined. After that, in step S121, the antenna number of the corresponding antenna 10 which is the result of the position determination and the signal indicating the vicinity are transmitted to the corresponding antenna 10. After that, this process ends.
　一方、ステップＳ１１６で、対応アンテナのＲＳＳＩが第１閾値以下であると判別された場合は、ステップＳ１２２の位置判定で、無線タグ１１は、対応アンテナ１０の識別領域３１のうち近傍領域３２の外、即ち、遠隔領域３３にあると判定される。その後、ステップＳ１２１で、位置判定の結果である対応アンテナ１０のアンテナ番号と、遠隔を示す信号が、対応アンテナ１０に送信される。その後、今回の処理は終了する。 On the other hand, when it is determined in step S116 that the RSSI of the corresponding antenna is equal to or less than the first threshold value, in the position determination in step S122, the wireless tag 11 is outside the neighborhood area 32 of the identification area 31 of the corresponding antenna 10. That is, it is determined that the remote area 33 is located. After that, in step S121, the antenna number of the corresponding antenna 10 which is the result of the position determination and the signal indicating the remoteness are transmitted to the corresponding antenna 10. After that, this process ends.
　位置検知システムの制御部には、上述するように、各アンテナ１０のそれぞれに対応づけられて、無線タグ１１の位置を検知するための識別領域３１が設定され、記憶されている。また、制御部には、近傍領域３２と遠隔領域３３とが記憶されている。従って、位置検知システムは、対応アンテナ１０が、無線タグ１１から、対応アンテナ１０のアンテナ番号と、近傍か遠隔かの信号を受信することで、受信した信号に応じた無線タグ１１の位置を特定することができる。 As described above, in the control unit of the position detection system, an identification area 31 for detecting the position of the wireless tag 11 is set and stored in association with each of the antennas 10. Further, the control unit stores the near area 32 and the remote area 33. Therefore, the position detection system identifies the position of the wireless tag 11 according to the received signal by the corresponding antenna 10 receiving the antenna number of the corresponding antenna 10 and a signal of near or remote from the wireless tag 11. can do.
　以上の処理によれば、アンテナ１０の高さが異なる場合でも、第１閾値に対し、そのアンテナごとの近傍領域３２と遠隔領域３３との境界位置とを対応させることで、無線タグ１１がその対応アンテナ１０の識別領域３１の中の、どの位置にいるのかをある程度正確に特定することができる。通常、設置されるアンテナ１０の間隔や高さを同一又は設計値どおりにすることは困難であるが、本実施の形態の位置検知システムであれば、アンテナ設置後に、第１閾値を調整することで対応できる。 According to the above processing, even if the heights of the antennas 10 are different, the wireless tag 11 can be used by associating the boundary position between the near region 32 and the remote region 33 for each antenna with respect to the first threshold value. It is possible to accurately identify the position in the identification area 31 of the corresponding antenna 10 to some extent. Normally, it is difficult to make the intervals and heights of the installed antennas the same or according to the design values, but in the position detection system of the present embodiment, the first threshold value is adjusted after the antennas are installed. Can be handled with.
　通常、電波干渉防止とタグ検知周期の問題からアンテナ設置密度には制約がある。これに対し、本実施の形態の位置検知システムであれば、１つのアンテナに対し、２つの分割エリアに分けて位置を判定することができる。従って、少ないアンテナ設置数で、より細かく位置を特定する事ができる。 Normally, there are restrictions on the antenna installation density due to problems with radio wave interference prevention and tag detection cycle. On the other hand, in the position detection system of the present embodiment, the position can be determined by dividing one antenna into two divided areas. Therefore, the position can be specified more finely with a small number of antennas installed.
実施の形態２．
　図３は、実施の形態２の位置検知システムの構成を模式的に示す図である。実施の形態２の位置検知システムは、図１の位置検知システムと同様の構成を有している。図３に示されるように、実施の形態２の位置検知システムは、遠隔領域３３を、更に、対応アンテナ１０側のエリアｘ＿ｘと近接アンテナ側のエリアｘ＿ｙとの２つの分割エリアに分け、合計３つの分割エリアで、位置を特定することができる。 Embodiment 2.
FIG. 3 is a diagram schematically showing the configuration of the position detection system according to the second embodiment. The position detection system of the second embodiment has the same configuration as the position detection system of FIG. As shown in FIG. 3, the position detection system of the second embodiment further divides the remote area 33 into two divided areas, an area x_x on the corresponding antenna 10 side and an area x_y on the proximity antenna side, for a total of 3 The position can be specified by two divided areas.
　なお、説明の簡略化のため、以下の実施の形態２及び３において、「ｘ」は特定された対応アンテナ１０のアンテナ番号を示す数字を表し、「ｙ」は、対応アンテナ１０とアンテナセットを構成するアンテナのアンテナ番号を示す数字を表すものとする。また、あるアンテナ１０と共にアンテナセットを構成するアンテナ１０を、「近接アンテナ」と称することとする。 For the sake of simplification of the description, in the following embodiments 2 and 3, "x" represents a number indicating the antenna number of the specified corresponding antenna 10, and "y" indicates the corresponding antenna 10 and the antenna set. It shall represent a number indicating the antenna number of the constituent antenna. Further, the antenna 10 that constitutes an antenna set together with a certain antenna 10 is referred to as a "proximity antenna".
　無線タグ１１は、第１閾値に加え、第２閾値を記録している。無線タグ１１は、受信した電波のＲＳＳＩと第２閾値との比較により、遠隔領域３３のなかのどの分割エリアにあるかを判定する。ここで、第２閾値は、少なくとも第１閾値より小さな値である。具体的な第２閾値の値は、近接アンテナ１０から受信する電波の強度に応じて設定される。第２閾値を調整することで、対応アンテナ１０側のエリアｘ＿ｘと、近隣アンテナ側のエリアｘ＿ｙとの境界線が調整される。以下、実施の形態２の無線タグ１１による位置判定について具体的に説明する。 The wireless tag 11 records a second threshold value in addition to the first threshold value. The wireless tag 11 determines which division area in the remote area 33 is located by comparing the RSSI of the received radio wave with the second threshold value. Here, the second threshold value is at least a value smaller than the first threshold value. The specific value of the second threshold value is set according to the intensity of the radio wave received from the proximity antenna 10. By adjusting the second threshold value, the boundary line between the area x_x on the corresponding antenna 10 side and the area x_y on the neighboring antenna side is adjusted. Hereinafter, the position determination by the wireless tag 11 of the second embodiment will be specifically described.
　図４は、無線タグ１１による位置判定の動作を示すフローチャートである。図４のフローチャートは、ステップＳ１２２の処理に替えて、ステップＳ２０１～Ｓ２０３の処理を有する点を除き、図２と同一である。図２のフローチャートと同一のステップＳ１００～Ｓ１２１の処理については、説明を省略する。 FIG. 4 is a flowchart showing the operation of position determination by the wireless tag 11. The flowchart of FIG. 4 is the same as that of FIG. 2 except that the processing of steps S201 to S203 is performed instead of the processing of step S122. The process of steps S100 to S121, which is the same as the flowchart of FIG. 2, will not be described.
　図４のフローチャートに示されるように、無線タグ１１は、ステップＳ１１６において、対応アンテナ１０からの電波のＲＳＳＩが第１閾値以下であると判別された場合、次に、ステップＳ２０１に進み、無線タグ１１が受信した電波のうち、ＲＳＳＩが第２閾値を超える電波の受信数が１であるか否かが判別される。 As shown in the flowchart of FIG. 4, when it is determined in step S116 that the RSSI of the radio wave from the corresponding antenna 10 is equal to or less than the first threshold value, the wireless tag 11 proceeds to step S201 and then proceeds to the wireless tag. Among the radio waves received by 11, it is determined whether or not the number of received radio waves whose RSSI exceeds the second threshold value is 1.
　ステップＳ２０１で、第２閾値を超える電波の受信数が１であると判別された場合には、対応アンテナ１０からのみ第２閾値を超える強度の電波を受信していると判断できる。この場合、処理はステップＳ２０２に進み、対応アンテナ１０側の遠隔領域ｘ＿ｘと位置判定され、ステップＳ１２１に進み、位置判定結果が通知される。 If it is determined in step S201 that the number of received radio waves exceeding the second threshold value is 1, it can be determined that radio waves having an intensity exceeding the second threshold value are received only from the corresponding antenna 10. In this case, the process proceeds to step S202, the position is determined as the remote area x_x on the corresponding antenna 10 side, the process proceeds to step S121, and the position determination result is notified.
　一方、ステップＳ２０１で受信数が１ではないと判別された場合には、受信数は２であり、第２閾値を超える強度の電波を、対応アンテナ１０と近隣アンテナ１０とから受信していると判断できる。この場合、処理はステップＳ２０３に進み、近隣アンテナ１０側の遠隔領域ｘ＿ｙと位置判定された後、ステップＳ１２１に進み、位置判定結果が対応アンテナ１０に通知される。 On the other hand, when it is determined in step S201 that the number of receptions is not 1, the number of receptions is 2, and it is said that radio waves having an intensity exceeding the second threshold value are received from the corresponding antenna 10 and the neighboring antenna 10. I can judge. In this case, the process proceeds to step S203, and after the position is determined as the remote area x_y on the neighboring antenna 10 side, the process proceeds to step S121, and the position determination result is notified to the corresponding antenna 10.
　上述したように、位置検知システムの制御部には、近傍領域３２と遠隔領域３３とが記憶されている。更に、第２閾値の調整により、遠隔領域３３の分割エリアｘ＿ｘ、ｘ＿ｙの境界が調整され、位置検知システムの制御部には、各識別領域３１のなかの、分割エリアｘ＿ｘとｘ＿ｙが記憶されている。従って、無線タグ１１が対応アンテナ１０の遠隔領域３３にあると判定された場合に、対応アンテナ１０が受信する「ｘ＿ｘ」または「ｘ＿ｙ」の信号に基づいて、位置検知システムの制御部は、無線タグ１１の位置を検出することができる。 As described above, the control unit of the position detection system stores the near area 32 and the remote area 33. Further, by adjusting the second threshold value, the boundaries of the divided areas x_x and x_y of the remote area 33 are adjusted, and the control unit of the position detection system stores the divided areas x_x and x_y in each of the identification areas 31. There is. Therefore, when it is determined that the wireless tag 11 is in the remote region 33 of the corresponding antenna 10, the control unit of the position detection system wirelessly receives the signal of "x_x" or "x_y" received by the corresponding antenna 10. The position of the tag 11 can be detected.
　以上説明した通り、本実施の形態２によれば、対応アンテナ１０と近隣アンテナ１０とからそれぞれ送信された電波の受信強度を比較することで、対応アンテナ１０の位置検知エリアを、更に細かく分割することができる。また、設置されるアンテナ１０の間隔や高さにばらつきがある場合にも、アンテナ１０の設置後に、第１閾値及び第２閾値を調整することで、正確に位置の特定を行うことができる。 As described above, according to the second embodiment, the position detection area of the corresponding antenna 10 is further subdivided by comparing the reception intensities of the radio waves transmitted from the corresponding antenna 10 and the neighboring antenna 10. be able to. Further, even when the intervals and heights of the antennas 10 to be installed vary, the positions can be accurately specified by adjusting the first threshold value and the second threshold value after the antenna 10 is installed.
　なお、本実施の形態２では、２つのアンテナ１０が設置されている場合について説明した。しかし、本実施の形態２の位置判定は、３以上のアンテナが一列方向に設置されている場合にも適用することができる。この場合、各アンテナ１０と、通信領域２０の一部が重複する他の２つの近接アンテナ１０とが、アンテナセットとして登録される。 In the second embodiment, the case where two antennas 10 are installed has been described. However, the position determination of the second embodiment can be applied even when three or more antennas are installed in a single row direction. In this case, each antenna 10 and the other two proximity antennas 10 whose communication areas 20 partially overlap are registered as an antenna set.
　そして、２つの近隣アンテナ１０に挟まれたアンテナ１０に対応づけられた識別領域３１の遠隔領域３３は、アンテナ番号がｙ１である一方の近隣アンテナ１０に近い遠隔領域ｘ＿ｙ１と、アンテナ番号がｙ２である他方の近隣アンテナ１０に近い遠隔領域ｘ＿ｙ２と、その間の対応アンテナ１０に近い遠隔領域ｘ＿ｘとの３つの分割エリアに分けられ、位置情報が検知される。 The remote area 33 of the identification area 31 associated with the antenna 10 sandwiched between the two neighboring antennas 10 has a remote area x_y1 close to the one neighboring antenna 10 having an antenna number of y1 and an antenna number of y2. The position information is detected by being divided into three divided areas of a remote area x_y2 close to the other neighboring antenna 10 and a remote area x_x close to the corresponding antenna 10 in between.
　アンテナセットが３つである場合の具体的な位置特定は図４に示す処理により実行することができる。即ち、図４のステップＳ２０１で、第２閾値を越える電波の受信数が２以上であると判別された場合、ステップＳ２０３の処理で、第２閾値を超える電波を送信した近隣アンテナ１０のアンテナ番号ｙが特定されることで、遠隔領域のうちエリアｘ＿ｙにいることが特定される。 Specific position identification when there are three antenna sets can be executed by the process shown in FIG. That is, when it is determined in step S201 of FIG. 4 that the number of received radio waves exceeding the second threshold value is 2 or more, the antenna number of the neighboring antenna 10 that has transmitted the radio wave exceeding the second threshold value in the process of step S203. By specifying y, it is specified that the user is in the area x_y in the remote area.
実施の形態３．
　図５は、実施の形態３の位置検知システムの構成を模式的に示す図である。実施の形態３の例では、番号１～４の４つのアンテナ１０が隣接して設置されている。４つのアンテナ１０それぞれは、無線タグ１１との通信領域２０の一部が、他の３つのアンテナ１０と無線タグ１１との通信領域２０の一部と、互いに重なるように設置されている。これら４つのアンテナ１０は、アンテナセットとして登録されている。 Embodiment 3.
FIG. 5 is a diagram schematically showing the configuration of the position detection system according to the third embodiment. In the example of the third embodiment, the four antennas 10 of Nos. 1 to 4 are installed adjacent to each other. Each of the four antennas 10 is installed so that a part of the communication area 20 with the wireless tag 11 overlaps with a part of the communication area 20 between the other three antennas 10 and the wireless tag 11. These four antennas 10 are registered as an antenna set.
　図５に示されるように、番号ｘのアンテナ１０に対応する識別領域３１は、近傍領域３２と遠隔領域３３とに分けられ、位置判定される。更に、遠隔領域３３は、どの近隣アンテナ１０からも第２閾値を超える強度の電波を受信しないエリアと、他の近隣アンテナ１０の１つから第２閾値を超える強度の電波を受信するエリアと、他の２以上の近隣アンテナ１０から第２閾値を超える強度の電波を受信するエリアとの４つのエリアに分けて、位置判定される。 As shown in FIG. 5, the identification area 31 corresponding to the antenna 10 of the number x is divided into a near area 32 and a remote area 33, and the position is determined. Further, the remote area 33 includes an area in which radio waves having an intensity exceeding the second threshold value are not received from any neighboring antenna 10 and an area in which radio waves having an intensity exceeding the second threshold value are received from one of the other neighboring antennas 10. The position is determined by dividing into four areas, one is an area for receiving radio waves having an intensity exceeding the second threshold value from the other two or more neighboring antennas 10.
　４つのエリアは、対応アンテナ１０のアンテナ番号ｘと近隣アンテナ１０のアンテナ番号ｙとで特定される。具体的に、ある対応アンテナ１０以外の近接アンテナ１０から第２閾値を超える強度の電波を受信しない場合、対応アンテナ１０のアンテナ番号ｘ＿ｘが送信されて、エリアが特定される。例えば、対応アンテナ１０がアンテナ番号１のアンテナである場合、図５のエリア１＿１が、ある対応アンテナ１０以外の近接アンテナ１０から第２閾値を超える強度の電波を受信しない場合に特定されるエリアである。 The four areas are specified by the antenna number x of the corresponding antenna 10 and the antenna number y of the neighboring antenna 10. Specifically, when a radio wave having an intensity exceeding the second threshold value is not received from the proximity antenna 10 other than the corresponding antenna 10, the antenna number x_x of the corresponding antenna 10 is transmitted to specify the area. For example, when the corresponding antenna 10 is the antenna of the antenna number 1, the area 1-11 of FIG. 5 is an area specified when a radio wave having an intensity exceeding the second threshold value is not received from the proximity antenna 10 other than the corresponding antenna 10. is there.
　近接アンテナ１０の１つから第２閾値を超える強度の電波を受信した場合、対応アンテナ１０のアンテナ番号ｘと、第２閾値を超える強度の電波を送信した近接アンテナのアンテナ番号ｙとが送信されて、エリアが特定される。例えば、対応アンテナ１０がアンテナ番号１で、アンテナ番号４の近接アンテナ１０から、第２閾値を超える電波を受信した場合に特定されるエリアは、図５のエリア１＿４である。 When a radio wave having an intensity exceeding the second threshold value is received from one of the proximity antennas 10, the antenna number x of the corresponding antenna 10 and the antenna number y of the proximity antenna that has transmitted the radio wave having an intensity exceeding the second threshold value are transmitted. The area is specified. For example, the area specified when the corresponding antenna 10 is the antenna number 1 and the radio wave exceeding the second threshold value is received from the proximity antenna 10 of the antenna number 4 is the area 1_4 in FIG.
　近接アンテナ１０の２つ以上から第２閾値を超える強度の電波を受信した場合、無線タグ１１は、３つ又は全てのアンテナの通信領域２０が重複するエリアにある。このエリアは、対応アンテナ１０のアンテナ番号ｘと、その対応アンテナ１０の対角線上に配置された近接アンテナ１０のアンテナ番号ｚとで特定される。例えば、対応アンテナ１０がアンテナ番号１で、２つ以上の近接アンテナから、第２閾値を超える電波を受信した場合に特定されるエリアは、図５のエリア１＿３である。各アンテナ１０に対する対角線上のアンテナ番号ｚは、無線タグ１１に予め記憶されていてもよい。また、アンテナ番号の送信に替えて、何らかの信号ｚを、３つ以上の通信領域２０が重複するエリアにあることを示す信号としてｘ＿ｚを送信することとしてもよい。 When radio waves having a strength exceeding the second threshold value are received from two or more of the proximity antennas 10, the radio tag 11 is in an area where the communication areas 20 of the three or all antennas overlap. This area is specified by the antenna number x of the corresponding antenna 10 and the antenna number z of the proximity antenna 10 arranged diagonally of the corresponding antenna 10. For example, the area specified when the corresponding antenna 10 has the antenna number 1 and receives radio waves exceeding the second threshold value from two or more proximity antennas is the area 1_3 of FIG. The diagonal antenna number z for each antenna 10 may be stored in advance in the wireless tag 11. Further, instead of transmitting the antenna number, some signal z may be transmitted as x_z as a signal indicating that the three or more communication areas 20 are in the overlapping area.
　位置検知システムの制御部には、無線タグ１１から送信される遠隔領域３３内のエリアを示す信号「ｘ＿ｘ」又は「ｘ＿ｙ」又は「ｘ＿ｚ」に対応する各位置が記憶されている。従って、無線タグ１１が遠隔領域３３内のエリアを示すこれらの信号を送信することで、制御部において、位置を特定することができる。 The control unit of the position detection system stores each position corresponding to the signal "x_x" or "x_y" or "x_z" indicating the area in the remote area 33 transmitted from the wireless tag 11. Therefore, the radio tag 11 can identify the position in the control unit by transmitting these signals indicating the area in the remote area 33.
　図６は、無線タグ１１による位置判定の動作を示すフローチャートである。図６のフローチャートは、ステップＳ２０１～Ｓ２０３の処理に替えて、ステップＳ３０１～Ｓ３０６の処理を有する点を除き、図４のフローチャートと同一である。図２又は図４と同一のステップＳ１００～Ｓ１２１の処理については説明を省略する。 FIG. 6 is a flowchart showing the operation of position determination by the wireless tag 11. The flowchart of FIG. 6 is the same as the flowchart of FIG. 4 except that the processing of steps S301 to S306 is performed instead of the processing of steps S201 to S203. The description of the process of steps S100 to S121 which is the same as that of FIG. 2 or 4 will be omitted.
　図６の処理では、ステップＳ１１６において、対応アンテナ１０からの電波のＲＳＳＩが第１閾値以下であると判別された場合には、次に、ステップＳ３０１に進み、ＲＳＳＩが第２閾値を超える強度の電波の受信数が確認される。確認の結果、その受信数が１であれば、受信した電波は対応アンテナ１０から送信された電波であると判断される。この場合、ステップＳ３０２に進み、遠隔領域３３のうち、対応アンテナ１０のみから第２閾値以上電波を受信するエリアｘ＿ｘにあると判定される。その後、処理はステップＳ１２１に進み、位置判定の結果として、信号ｘ＿ｘが対応アンテナ１０に通知される。 In the process of FIG. 6, if it is determined in step S116 that the RSSI of the radio wave from the corresponding antenna 10 is equal to or less than the first threshold value, the process proceeds to step S301, and the intensity of the RSSI exceeds the second threshold value. The number of received radio waves is confirmed. As a result of the confirmation, if the number of receptions is 1, it is determined that the received radio wave is the radio wave transmitted from the corresponding antenna 10. In this case, the process proceeds to step S302, and it is determined that the remote area 33 is in the area x_x that receives radio waves of the second threshold value or more from only the corresponding antenna 10. After that, the process proceeds to step S121, and as a result of the position determination, the signal x_x is notified to the corresponding antenna 10.
　ステップＳ３０１で、第２閾値を超える強度の電波の受信数が２であると判別された場合には、処理はステップＳ３０３に進み、第２閾値を越える強度の電波を送信した近接アンテナ１０の番号ｙが記憶される。次に、ステップＳ３０４の位置判定に進み、エリア「ｘ＿ｙ」にあると判定される。その後、処理はステップＳ１２１に進み、位置判定の結果として、信号ｘ＿ｙが対応アンテナ１０に通知される。 If it is determined in step S301 that the number of received radio waves having an intensity exceeding the second threshold value is 2, the process proceeds to step S303, and the number of the proximity antenna 10 that transmits the radio waves having an intensity exceeding the second threshold value. y is stored. Next, the process proceeds to the position determination in step S304, and it is determined that the area "x_y" is located. After that, the process proceeds to step S121, and as a result of the position determination, the signal x_y is notified to the corresponding antenna 10.
　ステップＳ３０１で、第２閾値を超える強度の電波の受信数が３以上であると判別された場合には、処理はステップＳ３０５に進み、対応アンテナ１０に対し対角線上の位置にあるアンテナ番号ｚが記憶される。次に、ステップＳ３０６の位置判定に進み、対応アンテナ１０のアンテナ番号ｘと、対角位置のアンテナ番号ｚとで特定されるエリア「ｘ＿ｚ」にあると判定される。その後、処理はステップＳ１２１に進み、位置判定の結果として、信号ｘ＿ｚが対応アンテナ１０に通知される。 If it is determined in step S301 that the number of received radio waves having an intensity exceeding the second threshold value is 3 or more, the process proceeds to step S305, and the antenna number z located diagonally with respect to the corresponding antenna 10 is It will be remembered. Next, the process proceeds to the position determination in step S306, and it is determined that the antenna number x of the corresponding antenna 10 is in the area “x_z” specified by the antenna number z at the diagonal position. After that, the process proceeds to step S121, and as a result of the position determination, the signal x_z is notified to the corresponding antenna 10.
　以上説明したように、本実施の形態によれば、４つのアンテナを１つのアンテナセットとすることで、１つのアンテナに対する領域を、５つのエリアに分けて、位置情報を検出することができる。これにより、アンテナの設置台数を増やすことなく、より詳細な位置検出を行うことができる。また、設置されるアンテナ１０の間隔や高さにばらつきがある場合にも、アンテナ１０の設置後に、第１閾値及び第２閾値を調整することで、正確に位置の特定を行うことができる。 As described above, according to the present embodiment, by using four antennas as one antenna set, the area for one antenna can be divided into five areas and the position information can be detected. As a result, more detailed position detection can be performed without increasing the number of installed antennas. Further, even when the intervals and heights of the antennas 10 to be installed vary, the positions can be accurately specified by adjusting the first threshold value and the second threshold value after the antenna 10 is installed.
　なお、説明の簡略化のため、４つのアンテナを１セットとする１つのアンテナセットに対応する１つの領域の位置情報検出を図示して説明したが、本実施の形態はこれに限られず、図７に示されるように、４つのアンテナを１セットとアンテナセットに対応する領域が、複数並んで配置される構成としてもよい。この場合にも、図６のフローチャートにより、無線タグ１１が遠隔領域３３にある場合、その遠隔領域３３の４つの分割エリアのどこにあるかをそれぞれ特定することができる。 For the sake of simplification of the description, the position information detection of one region corresponding to one antenna set including four antennas has been illustrated and described, but the present embodiment is not limited to this, and the figure is shown in the figure. As shown in 7, a set of four antennas and a plurality of regions corresponding to the antenna sets may be arranged side by side. Also in this case, when the wireless tag 11 is in the remote area 33, it is possible to specify where in each of the four divided areas of the remote area 33 by the flowchart of FIG.
　また、本実施の形態の位置検知システムは、４つのアンテナを１つのセットとして位置を特定するため、設置するアンテナの台数は、４の倍数である事が望ましい。ただし、４の倍数でない場合にも、これを適用することは可能である。 Further, since the position detection system of the present embodiment specifies the position with four antennas as one set, it is desirable that the number of antennas to be installed is a multiple of 4. However, it is possible to apply this even if it is not a multiple of 4.
　図８に、アンテナ１０の台数が６つの例を示す。アンテナの台数が４の倍数ではない場合には、４の倍数となるように、いくつかのアンテナを２つのアンテナセットに重複して設定すればよい。例えば、図８の例では、中央の列に配置されている２番と３番のアンテナが、２つのアンテナセット４０、４１に重複して配置されている。これにより、図６のフローチャートに示すのと同様の方法で、対応アンテナ１０ごとに遠隔領域３３を４つの分割エリアに分けて、位置情報を取得することができる。 FIG. 8 shows an example in which the number of antennas 10 is six. If the number of antennas is not a multiple of 4, some antennas may be duplicated in the two antenna sets so that they are a multiple of 4. For example, in the example of FIG. 8, the antennas No. 2 and No. 3 arranged in the central row are overlapped in the two antenna sets 40 and 41. Thereby, the remote area 33 can be divided into four divided areas for each corresponding antenna 10 and the position information can be acquired by the same method as shown in the flowchart of FIG.
　図９～図１０に、アンテナ１０の台数が４の倍数でない場合の他の例を示す。図９に示される例では、アンテナセットを構成するアンテナの台数が３台であり、各アンテナ１０は、１のアンテナセットのみに含まれる。この場合にも、無線タグ１１は、図６のフローチャートと同様の処理により位置情報の検知を行うことができる。 9 to 10 show another example when the number of antennas 10 is not a multiple of 4. In the example shown in FIG. 9, the number of antennas constituting the antenna set is three, and each antenna 10 is included in only one antenna set. Also in this case, the wireless tag 11 can detect the position information by the same processing as the flowchart of FIG.
　ただし、近接するアンテナ数が少なくなる分、分割可能なエリア数が減少する。具体的に、図９に示される例では、図５に示す実施の形態３の構成例に対して、４番のアンテナが不足している。その結果、４番のアンテナ１０からの電波によって特定される対応アンテナ１０が１番である場合のエリア１＿４及び対応アンテナ１０が３番である場合のエリア３＿４は特定することができず、それぞれ、エリア１＿１及び３＿３として特定される。このような場合であっても、位置検知システムの制御部に、近接アンテナ１０が欠けたことで通信領域２０が他の近接アンテナ１０と重複しなくなった領域を、対応アンテナ１０それぞれのエリアｘ＿ｘとして登録しておくことで、正しく位置検知を行うことができる。 However, the number of divisible areas decreases as the number of adjacent antennas decreases. Specifically, in the example shown in FIG. 9, the antenna No. 4 is insufficient with respect to the configuration example of the third embodiment shown in FIG. As a result, the area 1_4 when the corresponding antenna 10 specified by the radio wave from the fourth antenna 10 is No. 1 and the area 3_4 when the corresponding antenna 10 is No. 3 cannot be specified, respectively. Specified as areas 1_1 and 3_3. Even in such a case, the area where the communication area 20 does not overlap with the other proximity antennas 10 due to the lack of the proximity antenna 10 in the control unit of the position detection system is defined as the area x_x of each of the corresponding antennas 10. By registering, the position can be detected correctly.
　また、図１０に示される例では、アンテナセットを構成するアンテナは２台となる。この例でも、図６のフローチャートと同様の処理を実行することにより、位置情報の検知を行うことができる。ただしこの場合、図６のフローチャートのステップＳ３０１の処理において、第２閾値より強い電波の受信数は、１又は２のいずれかとなり、ステップＳ３０５～Ｓ３０６の処理が実行されることはない。この場合、対応アンテナ１０の遠隔領域３３の分割エリアは、近接アンテナ１０に近いｘ＿ｙであるか、あるいは、近接アンテナ１０からは遠いエリアｘ＿ｘであるかの２つとなる。 Further, in the example shown in FIG. 10, the number of antennas constituting the antenna set is two. In this example as well, the position information can be detected by executing the same process as the flowchart of FIG. However, in this case, in the process of step S301 in the flowchart of FIG. 6, the number of received radio waves stronger than the second threshold value is either 1 or 2, and the processes of steps S305 to S306 are not executed. In this case, the divided area of the remote area 33 of the corresponding antenna 10 is either x_y close to the proximity antenna 10 or an area x_x far from the proximity antenna 10.
　このように、アンテナ１０の設置台数が４台ではない場合にも、各アンテナ１０の識別領域３１を、アンテナセットを構成するアンテナ数＋１のエリアに分けて、位置情報を検出することができる。 In this way, even when the number of antennas 10 installed is not four, the identification area 31 of each antenna 10 can be divided into an area of the number of antennas constituting the antenna set + 1 and the position information can be detected.
　ただし、アンテナ数を５以上とすると、電波受信が重複し、受信電波の強度関係が複雑となり、かえってエリア分割数が減少することが考えられる。従って、アンテナセットのアンテナ台数は、好ましくは４台、又はそれ以下とすることが望ましい。 However, if the number of antennas is 5 or more, it is conceivable that radio wave reception will overlap, the strength relationship of the received radio waves will become complicated, and the number of area divisions will decrease. Therefore, it is desirable that the number of antennas in the antenna set is preferably 4 or less.
＜実施の形態１～３のその他の実施の形態＞
　なお、実施の形態１～３の位置検知システムの制御部は、アンテナ１０のそれぞれに搭載されていてもよいし、全てのアンテナ１０と通信可能な状態で、いずれかのアンテナ１０又はアンテナ１０とは別の場所に設置された装置に搭載されたものであってもよい。 <Other Embodiments 1 to 3>
The control unit of the position detection system of the first to third embodiments may be mounted on each of the antennas 10, or may be connected to any of the antennas 10 or 10 in a state of being able to communicate with all the antennas 10. May be mounted on a device installed at another location.
　また、実施の形態１～３では、無線タグ１１が、その対応アンテナ１０の特定と、位置判定とを行い、結果を、対応アンテナ１０に送信する場合について説明した。しかしながら、同様の位置判定の機能を、アンテナ１０側に持たせる構成としてもよい。この場合、例えば、無線タグ１１は、対応アンテナ１０を特定し、対応アンテナ１０に対し、受信した電波のＲＳＳＩの値を送信し、対応アンテナ１０側、または別途設置された制御部で、ＲＳＳＩと第１閾値との比較及び第２閾値との比較を実行することで、無線タグ１１の位置を特定する構成としてもよい。 Further, in the first to third embodiments, the case where the wireless tag 11 identifies the corresponding antenna 10 and determines the position and transmits the result to the corresponding antenna 10 has been described. However, the antenna 10 may be provided with the same position determination function. In this case, for example, the wireless tag 11 identifies the corresponding antenna 10, transmits the RSSI value of the received radio wave to the corresponding antenna 10, and displays the RSSI on the corresponding antenna 10 side or a separately installed control unit. The position of the radio tag 11 may be specified by executing the comparison with the first threshold value and the comparison with the second threshold value.
　また、実施の形態１～３では、各アンテナ１０の通信領域２０に接する立方体の領域を識別領域３１として登録する場合について説明した。しかし、識別領域３１はこれに限られず、例えば、各アンテナ１０の通信領域２０のうち、他の通信領域２０と交差する面よりそのアンテナ１０側の領域の全てを、そのアンテナ１０に対応する識別領域として登録するように構成してもよい。 Further, in the first to third embodiments, the case where the cube region in contact with the communication region 20 of each antenna 10 is registered as the identification region 31 has been described. However, the identification area 31 is not limited to this, and for example, among the communication areas 20 of each antenna 10, all the areas on the antenna 10 side of the surface intersecting the other communication areas 20 are identified corresponding to the antenna 10. It may be configured to be registered as an area.
　また、実施の形態１～３では、位置判定の結果を、対応アンテナ１０だけに送信する構成について説明した。このように送信するアンテナを対応アンテナ１０に限定することで、消費電力の低減を図ることができる。しかしながら、この構成に限られるものではなく、例えば、位置判定の結果が、アンテナセットを構成する全てのアンテナ１０に送信される構成としてもよい。 Further, in the first to third embodiments, the configuration in which the result of the position determination is transmitted only to the corresponding antenna 10 has been described. By limiting the antennas to be transmitted in this way to the corresponding antennas 10, power consumption can be reduced. However, the present invention is not limited to this configuration, and for example, the position determination result may be transmitted to all the antennas 10 constituting the antenna set.
　１０　アンテナ、　１１　無線タグ、　２０　通信領域、　３１　識別領域、　３２　近傍領域、　３３　遠隔領域、　４０、４１　アンテナセット 10 antennas, 11 wireless tags, 20 communication areas, 31 identification areas, 32 neighborhood areas, 33 remote areas, 40, 41 antenna sets

Claims (3)

  1. 　携帯して移動可能な無線タグと、
    　前記無線タグと通信する複数のアンテナと、
    　を備え、
    　前記無線タグの位置を検知する位置検知システムであって、
    　前記アンテナのそれぞれは、前記無線タグとの通信領域の一部が、少なくとも１つの他のアンテナと前記無線タグとの通信領域の一部と重なるように配置され、
    　前記アンテナのそれぞれと、前記他のアンテナとは、互いに電波干渉しない間欠的なタイミングで電波送信する機能を備え、
    　前記無線タグは、
    　前記アンテナから送信された電波を受信すると共に電波受信強度を測定し、
    　前記電波受信強度が最も大きい電波を送信したアンテナを、前記無線タグに最も近いアンテナである対応アンテナとして特定し、
    　前記対応アンテナからの電波の前記電波受信強度と第１閾値との比較により、前記無線タグの位置が、前記対応アンテナの前記通信領域のなかの、前記対応アンテナから一定の範囲内にある近傍領域にあるか、前記近傍領域の外側の遠隔領域にあるかを特定し、
    　前記アンテナに、特定した前記無線タグの位置の応答を送信する、
    　ように構成されている無線タグの位置検知システム。     Wireless tags that can be carried and moved,
    A plurality of antennas that communicate with the wireless tag,
    With
    A position detection system that detects the position of the wireless tag.
    Each of the antennas is arranged so that a part of the communication area with the radio tag overlaps with a part of the communication area between at least one other antenna and the radio tag.
    Each of the antennas and the other antennas have a function of transmitting radio waves at intermittent timings that do not interfere with each other.
    The wireless tag is
    The radio wave transmitted from the antenna is received and the radio wave reception intensity is measured.
    The antenna that transmitted the radio wave having the highest radio wave reception strength was identified as the corresponding antenna that is the closest antenna to the radio tag.
    By comparing the radio wave reception intensity of the radio wave from the corresponding antenna with the first threshold value, the position of the radio tag is in the vicinity region within a certain range from the corresponding antenna in the communication area of the corresponding antenna. Identify whether it is in a remote area outside the neighborhood area
    Sends a response to the antenna at the location of the identified radio tag.
    A wireless tag position detection system that is configured to.
  2. 　前記通信領域の一部が互いに重なる複数のアンテナのセットである少なくとも１つのアンテナセットが登録され、
    　前記アンテナセットを構成する前記アンテナそれぞれの前記通信領域のなかの前記遠隔領域には、前記アンテナセットを構成するアンテナの数に応じた複数の分割エリアの区分けが設定され、
    　前記無線タグは、
    　前記対応アンテナの前記遠隔領域にあると判定した場合、
    　前記アンテナセットを構成する全ての前記アンテナからの電波送信が完了する時間の間に、前記第１閾値よりも小さな値である第２閾値よりも大きな電波受信強度の電波を受信した件数である受信数を検出し、
    　前記受信数に基づいて、前記無線タグの位置が、前記遠隔領域のなかの複数の分割エリアのうち、どの分割エリアにあるかを特定する、
    　ように構成されている請求項１に記載の無線タグの位置検知システム。     At least one antenna set, which is a set of a plurality of antennas in which a part of the communication area overlaps with each other, is registered.
    In the remote area within the communication area of each of the antennas constituting the antenna set, division of a plurality of divided areas according to the number of antennas constituting the antenna set is set.
    The wireless tag is
    When it is determined that the corresponding antenna is in the remote area,
    The number of receptions that received radio waves with a radio wave reception strength higher than the second threshold value, which is a value smaller than the first threshold value, during the time when radio wave transmission from all the antennas constituting the antenna set is completed. Detect the number and
    Based on the number of receptions, the position of the radio tag is specified in which division area among the plurality of division areas in the remote area.
    The position detection system for a wireless tag according to claim 1, which is configured as described above.
  3. 　前記無線タグは、前記無線タグの位置の応答を、前記対応アンテナに限って送信するように構成されている請求項１又は２に記載の無線タグの位置検知システム。 The position detection system for a wireless tag according to claim 1 or 2, wherein the wireless tag is configured to transmit a response of the position of the wireless tag only to the corresponding antenna.
PCT/JP2019/023723 2019-06-14 2019-06-14 Position detection system for wireless tag WO2020250437A1 (en)

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