Communication device, information processing device, and location information management method

Abstract

The communication device detects a wireless device and calculates a relative position of the detected wireless device relative to a reference wireless device, which is used as a reference for position identification, based on an amount of movement of the communication device when the communication device detects the reference wireless device. The communication device associates the calculated relative position with identification information about the detected wireless device and identification information about the reference wireless device.

Description

Technical Field

[0001] The present invention relates to a technique for managing location information about wireless devices. Background Art

[0002] In logistics, inventory management, or animal management, systems that use ultra-high frequency (UHF) passive radio frequency identification tags (hereinafter referred to as RFID tags) as wireless devices to manage target items or animals are used. RFID tags receive radio waves (electromagnetic waves) emitted from the antenna of an RFID reader and use the power generated by the received radio waves (electromagnetic waves) to operate. This has the following advantages: no batteries are required and thin RFID tags can be manufactured at low cost. However, since RFID tags and RFID readers can only communicate within a short distance, there is a disadvantage that RFID tags present over a large area cannot be detected at once.

[0003] Therefore, a method for managing location information about management targets that are present over a large area and have RFID tags attached is being discussed. Specifically, an RFID reader configured to detect location information is carried, and upon detecting an RFID tag, the location information is automatically associated with identification (ID) information about the RFID tag. Japanese Patent Application Publication No. 2007-114003 discusses a technique for detecting location information about an RFID reader using a global positioning system (GPS).

[0004] Citation List

[0005] Patent Literature

[0006] PTL 1: Japanese Patent Application Publication No. 2007-114003 Summary of the Invention

[0007] However, the method of using GPS to detect the location information of the RFID reader is not suitable for indoor use. In addition, it is necessary to provide a GPS receiving circuit, so there is a problem of increasing the cost of the RFID reader.

[0008] Solution

[0009] Therefore, the present invention relates to a technology for easily managing position information on management target wireless devices existing in a large area while preventing cost increases.

[0010] According to one aspect of the present invention, a communication apparatus includes a detection unit configured to detect a wireless device; a calculation unit configured to calculate a relative position of the detected wireless device with respect to the first wireless device, based on an amount of movement of the communication apparatus when the communication apparatus detects the first wireless device to be used as a reference in identifying a position; and an association unit configured to associate the relative position calculated by the calculation unit, identification information about the detected wireless device, and identification information about the first wireless device.

[0011] According to another aspect of the present invention, an information processing device includes a receiving unit configured to receive, from a communication device that detects a wireless device, identification information about the detected wireless device and information about a relative position of the detected wireless device relative to a reference position; a calculating unit configured to calculate, based on the information received by the receiving unit, the relative position of the wireless device relative to the first wireless device using information about the relative position of a first wireless device to be used as a reference in identifying a position relative to the reference position and information about the relative position of a detected wireless device different from the first wireless device relative to the reference position; and an associating unit configured to associate the relative position calculated by the calculating unit, the identification information about the detected wireless device, and the identification information about the first wireless device. BRIEF DESCRIPTION OF THE DRAWINGS

[0012] Figure 1 is a diagram illustrating a radio frequency identification (RFID) reader 100 .

[0013] Figure 2A 1 is a diagram showing a moving object carrying the RFID reader 100 .

[0014] Figure 2B 1 is a diagram showing a moving object carrying the RFID reader 100 .

[0015] Figure 2C 1 is a diagram showing a moving object carrying the RFID reader 100 .

[0016] Figure 3 is a system diagram according to the first exemplary embodiment.

[0017] Figure 4 is a flowchart illustrating a control procedure of the RFID reader 100 according to the first exemplary embodiment.

[0018] Figure 5A is a diagram illustrating a display method of display unit 14 according to the first exemplary embodiment.

[0019] Figure 5B is a diagram illustrating a display method of the display unit 14 according to the first exemplary embodiment.

[0020] Figure 5C is a diagram illustrating a display method of the display unit 14 according to the first exemplary embodiment.

[0021] Figure 6 is a flowchart illustrating a control process for improving the accuracy of position information.

[0022] Figure 7 is a flowchart illustrating a control process for improving the accuracy of position information.

[0023] Figure 8 1 is a diagram showing a charging device 300 for the RFID reader 100 .

[0024] Figure 9 is a system diagram according to the second exemplary embodiment.

[0025] Figure 10 is a flowchart illustrating a control procedure of the RFID reader 100 according to the second exemplary embodiment.

[0026] Figure 11 is a flowchart illustrating a control procedure of server 20 according to the second exemplary embodiment.

[0027] Figure 12A is a diagram illustrating a display method of display unit 14 according to the second exemplary embodiment.

[0028] Figure 12B is a diagram illustrating a display method of display unit 14 according to the second exemplary embodiment.

[0029] Figure 12C is a diagram illustrating a display method of display unit 14 according to the second exemplary embodiment.

[0030] Figure 13 is a system diagram according to the third exemplary embodiment.

[0031] Figure 14 is a flowchart illustrating a control process of the RFID reader 200 according to the third exemplary embodiment.

[0032] Figure 15A 1 is a diagram showing a position RFID tag 30 and an item RFID tag 40 .

[0033] Figure 15B 1 is a diagram showing a position RFID tag 30 and an item RFID tag 40 .

[0034] Figure 16A 115 is a diagram showing the configuration of the antenna 115 .

[0035] Figure 16B115 is a diagram showing the configuration of the antenna 115 .

[0036] Figure 16C 115 is a diagram showing the configuration of the antenna 115 .

[0037] Figure 16D 115 is a diagram showing the configuration of the antenna 115 .

[0038] Figure 17A It is a diagram showing the radiation characteristics of the antenna 115.

[0039] Figure 17B It is a diagram showing the radiation characteristics of the antenna 115.

[0040] Figure 17C It is a diagram showing the radiation characteristics of the antenna 115.

[0041] Figure 18 is a diagram showing the hardware configuration of the server 20 . DETAILED DESCRIPTION

[0042] Methods for managing location information about management-target wireless devices according to various exemplary embodiments of the present invention will be described in detail below with reference to the accompanying drawings. In the management methods according to these exemplary embodiments, a communication device configured to detect wireless devices is carried by a mobile object, such as a person or machine, to detect wireless devices present over a large area. For example, the wireless device is a radio frequency identification (RFID) tag, and the communication device is an RFID reader.

[0043] like Figure 2A 、 Figure 2B and Figure 2C As shown, there are some methods, for example, a person (animal) wears an RFID reader 100 ( Figure 2A ) or attaching the RFID reader 100 to a machine (e.g., a drone 401 or an automated guided vehicle 501) ( Figure 2B and Figure 2C ). Using these methods, the RFID reader 100 can be moved over a wide range and RFID tags present in a large area can be detected.

[0044] The RFID reader 100 has the function of supplying ultra-high frequency (UHF) electromagnetic waves to the RFID tag, so that the integrated circuit (IC) chip in the RFID tag can operate and read the identification (ID) information stored in the memory unit of the RFID tag. In addition, the RFID reader 100 and the RFID tag can communicate with each other wirelessly at a distance of several meters.

[0045] In this exemplary embodiment, Figure 15BAs shown, the RFID tag attached to the management target (such as an article or an animal) will be referred to as an article RFID tag 40. The article RFID tag 40 is used to identify the management target to which the article RFID tag 40 is attached based on the ID information stored in the article RFID tag 40. Figure 15A As shown, the RFID tag used as a reference in identifying the position of the item RFID tag 40 will be referred to as the position RFID tag 30. The RFID reader 100 calculates the relative position of the item RFID tag 40 relative to the position RFID tag 30 as a reference using the movement amount detection sensor 104 described below.

[0046] Information about the relative position of the item RFID tag 40 with respect to the location RFID tag 30 is displayed on Figure 3 The display unit 14 in the display unit 14 is displayed so that the user can locate the management target to which the item RFID tag is attached. The details of each process will be described below in the following exemplary embodiments.

[0047] Although, in the exemplary embodiment of the present invention, an example in which an RFID tag is used as a communication device for detecting a target wireless device and an RFID reader is used as a communication device for detecting the wireless device is described, the wireless device and the communication device are not limited to those in the example. For example, other wireless communication such as short-range wireless communication, such as near field communication (NFC) or Alternatively, RFID using another frequency band may be used instead of UHF RFID.

[0048] First Exemplary Embodiment

[0049] Figure 1 1 is a circuit block diagram illustrating RFID reader 100 used in the first exemplary embodiment. RFID reader 100 is controlled by a computing unit 101, which includes one or more processors such as a central processing unit (CPU). A radio frequency (RF) control unit 110 outputs a UHF RF output from a transmission (TX) terminal based on control by computing unit 101. The RF output is amplified by a power amplifier 111, and then a low-pass filter 112 cuts off unnecessary frequency bands. The power of the RF output is variably set by computing unit 101. A coupler 113 is used to detect power via an RF power detection unit 116.

[0050] The power detection result of the RF power detection unit 116 can be detected by the calculation unit 101 as a radio frequency detection signal (RF_Detect signal). The coupler 114 is used to separate the RF output to the antenna unit 115 and the RF input received from the antenna unit 115. The antenna unit 115 is used to power the RFID tag and communicate with the RFID tag. The carrier cancellation unit 117 cancels the carrier component of the RF input based on the carrier cancellation signal (CARRIER_CANCEL signal). The signal component of the RF input is received by the receiving (RX) terminal of the RF control unit 110, and ID information as identification information about the RFID tag is detected.

[0051] The calculation unit 101 stores the ID information about the RFID tag detected by the RF control unit 110 in the storage unit 102, performs necessary data processing, and then communicates with the RFID tag through the communication unit 103. Figure 3 The storage unit 102 includes one or more memories such as a read-only memory (ROM) and a random access memory (RAM), and stores various types of data and programs to be processed by the computing unit 101. The communication unit 103 can communicate with the computing unit 101 by using Ethernet. The information terminal 10 can communicate with the information terminal 10 by wired communication using a universal serial bus (USB) or wireless communication using a wireless local area network (wireless LAN) or a public wireless system.

[0052] The movement amount detection sensor 104 is a sensor that includes a three-axis acceleration sensor, a gyroscope sensor, and a geomagnetic sensor, and detects the movement amount of the RFID reader 100. The movement amount detection sensor 104 is used to calculate the relative position of the position RFID tag 30 and the item RFID tag 40 as a reference. The movement amount detection sensor 104 can use any detection method by which the movement distance and movement direction of the RFID reader can be detected. In an exemplary embodiment of the present invention, information on a combination of the movement distance and the movement direction (two-dimensional or three-dimensional direction) is used as the movement amount.

[0053] When the RFID reader 100 automatically detects the ID information of the RFID tags, the movement detection sensor 104 calculates the relative positions of the RFID tags and associates the ID information of the plurality of RFID tags with the information about the relative positions of the plurality of RFID tags. The power supply unit 105 is a circuit including a battery and a direct current (DC)-DC converter for supplying a power supply voltage to the RFID reader 100.

[0054] Figure 3RFID tags are divided into position RFID tags 30 (30a to 30c) for detecting a reference position and item RFID tags 40 (40a to 40f) attached to a management target. Figure 15A and Figure 15B To describe the details of the RFID tag.

[0055] The RFID reader 100 associates the ID information about the item RFID tag 40, the ID information about the position RFID tag 30, the information about the relative position of the item RFID tag 40 with the position RFID tag 30, and the detection time of the item RFID tag 40. Then, this information is sent to the information terminal 10.

[0056] The information terminal 10 is an information terminal such as a smartphone or a personal computer (PC), and includes databases 11 and 12 and a display unit 14. The database 11 stores data in which ID information about the location RFID tags 30 and location names are associated with each other, and data in which ID information about the item RFID tags 40 and item names are associated with each other.

[0057] It is difficult for users to directly recognize the ID information about the RFID tag, so the ID information is converted into a name based on the database 11, and the converted name is displayed on the display unit 14. Alternatively, the ID information about the RFID tag can be directly displayed on the display unit without using the database 11.

[0058] The database 12 stores information received from the RFID reader 100. Specifically, the database 12 stores data in which the ID information about the location RFID tag 30, the ID information about the item RFID tag 40, the relative position of the item RFID tag 40 with respect to the location RFID tag 30, and the detection time of the item RFID tag 40 are associated with each other. The display unit 14 displays the item location information based on a user instruction via an interface (not shown) of the information terminal 10. Figure 5A 、 Figure 5B and Figure 5C A specific display method of the display unit 14 is described.

[0059] Figure 4 1 is a flowchart showing a method for detecting position information of an RFID tag of an object by the RFID reader 100 according to the present exemplary embodiment. If the power is turned on, the RFID reader 100 starts to control the detection of the position information of the object. The computing unit 101 of the RFID reader 100 executes the program stored in the storage unit 102, thereby realizing Figure 4 Each step in the flowchart.

[0060] In step S101, the RFID reader 100 sets information on a relative position to a reference position in the storage unit 102 to 0 (x=0, y=0, z=0). The reference position is the position of the RFID reader 100 at startup.

[0061] In step S102, the RFID reader 100 starts to control calculation of an integral value of the movement amount based on the detection result of the movement amount detection sensor 104, updates information about the relative position with respect to the reference position, and stores the information in the storage unit 102. In step S103, the RFID reader 100 periodically causes the RF control unit 110 to operate to communicate with the RFID tag, and starts controlling communication with the RFID tag.

[0062] In step S104, the RFID reader 100 determines whether the ID information about the RFID tag is acquired from the RFID tag. If the ID information about the RFID tag is acquired, the process proceeds to step S105. On the other hand, if the ID information about the RFID tag is not acquired, the process of step S104 is repeated.

[0063] In step S105, the RFID reader 100 determines whether the RFID tag is a location RFID tag 30 or an item RFID tag 40 based on the acquired ID information. For example, as a method of distinguishing between a location RFID tag 30 and an item RFID tag 40, the ID information about the RFID tag may include an identifier for distinguishing between the location RFID tag 30 and the item RFID tag 40. Furthermore, the determination may refer to the database 11 of the information terminal 10. If the RFID tag is an item RFID tag, the process proceeds to step S106. On the other hand, if the RFID tag is a location RFID tag, the process proceeds to step S108.

[0064] In step S106, the RFID reader 100 determines whether a reference position RFID tag has been set. If the reference position RFID tag has not been set, for example, immediately after the RFID reader 100 is activated, the process proceeds to step S107. On the other hand, if the reference position RFID tag has been set, the process proceeds to step S113.

[0065] In step S107, the RFID reader 100 stores data in which the ID information about the item RFID tag 40, the detection time of the item RFID tag 40, and the relative position of the item RFID tag 40 relative to the reference position (initial position at startup) are associated with each other in the storage unit 102.

[0066] In step S108, the RFID reader 100 stores the ID information of the detected position RFID tag 30 in the storage unit 102 as a reference position RFID tag, and the process proceeds to step S109. In step S109, the RFID reader 100 determines whether this is the first time the position RFID tag has been detected after the RFID reader 100 is activated. If this is the first time the position RFID tag has been detected, the process proceeds to step S110. On the other hand, if this is the second or subsequent time, the process proceeds to step S112.

[0067] In step S110, the RFID reader 100 performs the following processing on the data stored in the storage unit 102 in step S107. Specifically, based on the information regarding the relative position of the item RFID tag 40 relative to the reference position and the information regarding the relative position of the position RFID tag 30 relative to the reference position stored in the storage unit 102 in step S108, the relative position of the position RFID tag 30 and the item RFID tag 40 is calculated. As used herein, the term "reference position" refers to the initial position when the RFID reader 100 is activated (the position stored in step S101).

[0068] In step S111, the RFID reader 100 performs the following processing on the data stored in the storage unit 102 in step S107. Specifically, the RFID reader 100 associates the ID information about the item RFID tag 40, the ID information about the position RFID tag 30, the detection time of the item RFID tag 40, and the information about the relative position of the item RFID tag 40 with the position RFID tag 30. The RFID reader 100 then transmits this information to the information terminal 10. The communication unit 103 is used for this transmission.

[0069] In step S112, the RFID reader 100 sets the information about the relative position relative to the reference position in the storage unit 102 to 0 (x=0, y=0, z=0), and the process returns to step S102. In step S113, the RFID reader 100 associates the ID information about the detected item RFID tag 40, the ID information about the position RFID tag 30, the detection time of the item RFID tag 40, and the information about the relative position of the item RFID tag 40 with the position RFID tag 30. The RFID reader 100 then transmits this information to the information terminal 10.

[0070] The RFID reader 100 repeats the above control until receiving a system end request (S114). Through this process, the computing unit 101 of the RFID reader 100 controls the automatic detection of position information about the RFID tag 40 attached to the management target item and transmits the detected position information to the information terminal 10.

[0071] Figure 5A 、 Figure 5B and Figure 5C 1 shows a display example displayed on the display unit 14 of the information terminal 10. Figure 5A 、 Figure 5B and Figure 5C In the display example of , the position information about the management target item is displayed based on the information in the databases 11 and 12. Figure 5A 、 Figure 5B and Figure 5C In the display example of , the display unit 14 displays the position RFID tag 30 as a double circle and the item RFID tag 40 as a single circle.

[0072] Figure 5A The following example shows the display on display unit 14, where a user instructs information terminal 10 to display information regarding the North location on the 1st floor of the ABC Building at time XX. First, in database 12, the item detection time data closest to time XX is selected for each ID 40a to 40c (items a to c) of the item RFID tags 40 associated with ID 30a (the North location on the 1st floor of the ABC Building). Then, referring to information regarding the relative position of the item relative to the RFID location tag, display unit 14 displays the location information regarding items a to c, based on the location of the North location on the 1st floor of the ABC Building. The user can use the information displayed on display unit 14 and the assigned location RFID tags as markers to locate the actual item.

[0073] Figure 5B FIG. 1 shows an example of the display on the display unit 14 in the case where the user issues an instruction to display the 7th floor of the ABC building at time XX. Figure 5B, an example of a display is shown for a case where items d and e are each located on a floor other than the 7th floor of the ABC Building. If the height distance between items d and e and location RFID tag 30c on the 7th floor of the ABC Building is greater than a predetermined value, items d and e are detected as being located on a floor different from the 7th floor of the ABC Building. Display unit 14 displays each item located on a different floor as a dotted circle to indicate to the user that items d and e are not on the same floor as location RFID tag 30c. Based on the information regarding the relative position relative to location RFID tag 30c, display unit 14 displays a display indicating that item d is located on an upper floor of the 7th floor of the ABC Building and item e is located on a lower floor of the 7th floor of the ABC Building.

[0074] Figure 5C An example of a display on the display unit 14 is shown in the case where a user issues an instruction to display item c at time YY. For each ID 40c (item c) associated with location RFID tag 30a (ABC Building, 1st Floor, North) and location RFID tag 30b (ABC Building, 1st Floor, East), the item detection time data closest to time YY is selected. Then, referring to information regarding the relative position of the item relative to the location RFID tags, the display unit 14 displays the location of item c relative to the positions of location RFID tag 30a on the north side of ABC Building, 1st Floor, and location RFID tag 30b on the east side of ABC Building, 1st Floor (as a reference). This display method allows the user to locate item c using multiple location RFID tags as markers. The location RFID tags 30 are displayed as follows. Specifically, location RFID tag 30a associated with the detection data for item c closest to time YY is shown as a solid double circle, while location RFID tag 30b, another location RFID tag, is shown as a dashed double circle. This display method allows the user to prioritize the location information of items detected closest to the designated time YY.

[0075] As described above, the method for managing item location information according to the first exemplary embodiment uses the location RFID tag 30 as a reference for identifying the location used in item management. Therefore, the location RFID tag 30 does not need to be stored in association with a specific amount of location information. Therefore, users can easily introduce the location information detection system 1 by simply attaching the item RFID tag 40 to the management target and installing the location RFID tag 30.

[0076] When a user wants to locate an item, it is difficult for the user to intuitively locate the item even if quantitative coordinates indicating the item's location are displayed on the display unit 14. Displaying the item's location relative to the location of one or more location RFID tags 30 (as a reference) makes it easier for the user to locate the item.

[0077] The location RFID tag 30 does not require a power cable to be connected. Therefore, the location RFID tag 30 can be installed by a simple method, for example, by placing the location RFID tag 30 on the floor or attaching the location RFID tag 30 to a wall, thereby making it easy to introduce the location information detection system 1 not only for indoor use but also for outdoor use.

[0078] The position RFID tag 30 does not have to be located at a fixed location. For example, the position RFID tag 30 can be installed in a vehicle compartment to detect position information about items in the moving vehicle compartment.

[0079] As described above, the system for managing item position information according to the present exemplary embodiment can be easily introduced indoors and outdoors at low cost, and can manage position information on management targets with attached RFID tags present over a large area.

[0080] Second Exemplary Embodiment

[0081] Figure 9 is a system diagram according to the second exemplary embodiment. The system according to this exemplary embodiment differs from the first exemplary embodiment in that server 20, rather than RFID reader 100, processes the data required for position detection, and database 12 also manages the position RFID detection time in association. Each configuration similar to that in the first exemplary embodiment is given the same reference numeral, and redundant description thereof is omitted.

[0082] exist Figure 9 In the position detection system 2, a plurality of RFID readers 100 (100a, 100b, ...) are connected to a server 20. Each RFID reader 100 transmits data associated with ID information about RFID tags (item RFID tags 40 and location RFID tags 30), relative positions of RFID tags with respect to a reference position described below, and detection time of each RFID tag to the server 20. Figure 9 The time displayed in indicates that the detection times are performed in the order of 10, 11, 12, 20, 21 and 31.

[0083] Figure 181 shows the hardware configuration of the server 20 according to this exemplary embodiment. The storage unit 1801 includes one or more memories (such as one or both of ROM and RAM) and stores programs for executing various operations described below and the database described below. In addition to memories such as ROM and RAM, storage media such as a floppy disk, a hard disk, an optical disk, a magneto-optical disk, a compact disc (CD) ROM, a recordable CD (CD-R), a magnetic tape, a non-volatile memory card, or a digital versatile disc (DVD) can be used as the storage unit 1801.

[0084] The control unit 1802 includes Figure 9 The computing unit 23 shown includes, for example, one or more processors, such as a CPU and a microprocessing unit (MPU), an application-specific integrated circuit (ASIC), a digital signal processor (DSP), and a field-programmable gate array (FPGA). CPU is an abbreviation for central processing unit, and MPU is an abbreviation for microprocessing unit. Control unit 1802 executes the program stored in storage unit 1801, thereby controlling the entire device.

[0085] Input unit 1803 receives various operations from the user. Output unit 1804 outputs various types of outputs to the user. The output of output unit 1804 includes at least one of a display on a screen, audio output via a speaker, and a vibration output. Alternatively, input unit 1803 and output unit 1804 may be implemented by a single module, such as a touch panel. Communication unit 1805 may perform wired or wireless communication, and server 20 may communicate with an RFID reader using communication unit 1805.

[0086] exist Figure 9 In the system diagram of FIG. 1 , a database to be stored in the storage unit 1801 of the server 20 is shown. Figure 11 As described above, server 20 distinguishes between location RFID tags 30 and item RFID tags 40. When server 20 receives data from RFID reader 100 regarding location RFID tags 30, it stores the data in database 21a. When server 20 receives data regarding item RFID tags 40, it stores the data in database 21b. Databases 21a and 21b store ID information about RFID reader 100 to identify the RFID reader receiving the data. Databases 21a and 21b are used for temporary storage and are used by server 20 for data processing and database 12 generation.

[0087] In addition to storing the location names of location RFID tags 30, database 11 of server 20 also stores the installation times of the location RFID tags. Here, data is shown for the following situation: Location RFID tag 30 with ID 30a was installed on the north side of the 1st floor of the ABC building at time 10, then moved to and installed on the second floor of the ABC building at time 20. Location RFID tag 30 with ID 30b indicates that location RFID tag 30 was installed on the east side of the 1st floor of the ABC building at time 10.

[0088] The database 12 stores the ID information about the location RFID tag 30 , the ID information about the item RFID tag 40 , the relative position of the item RFID tag 40 with respect to the location RFID tag 30 , the detection time of the item RFID tag 40 , and the detection time of the location RFID tag 30 in association with each other.

[0089] Reference as follows Figure 12A 、 Figure 12B and Figure 12C As described above, using the installation time of the location RFID tag 30 in the database 11 and the installation time of the location RFID tag 30 in the database 12, data can be processed in a manner suitable for moving the location RFID tag 30. The RFID reader and the server 20 can communicate via a network such as the Internet or an intranet. The server 20, as an information processing device, can include a single device or multiple devices. In addition, the server 20 can include multiple devices that cooperate via a network such as a cloud. In addition, the server 20 and the information terminal 10 can be integrated.

[0090] Figure 10 1 is a flowchart showing the processing performed by the RFID reader 100 according to the present exemplary embodiment. The calculation unit 101 of the RFID reader 100 executes the program stored in the storage unit 102, thereby realizing Figure 10 Steps in the flowchart.

[0091] In step S221 , the RFID reader 100 transmits information associated with the RFID reader ID information, the RFID tag ID information, the RFID tag detection time, and the relative position of the RFID tag with respect to the reference position to the server 20 .

[0092] The RFID reader 100 according to this exemplary embodiment performs only minimal data processing and transmits data to the server 20, and the server 20 processes the data for position detection. Therefore, in the system 2 according to this exemplary embodiment, the data processing performed by the RFID reader 100 is reduced, so that the computing unit 101 with a low computing capacity can be used, and the necessary data capacity of the storage unit 102 is reduced.

[0093] Figure 11 18 is a flowchart showing the processing performed by the server 20 according to the present exemplary embodiment. The control unit 1802 of the server 20 executes the program stored in the storage unit 1801, thereby realizing Figure 11 Steps in the flowchart.

[0094] In step S201, the server 20 waits until data is transmitted from the RFID reader 100, and the process proceeds to step S202. In step S202, the server 20 determines whether the RFID reader 100 has been restarted by turning the power on and off. If the RFID reader 100 has been restarted, the reference position at the time of startup, which is used as a reference, is changed so that information regarding the relative positions in the RFID tag detection results before the restart and the RFID tag detection results after the restart can no longer be detected. Therefore, if the RFID reader 100 has been restarted, the process proceeds to steps S208 to S210, and the data processing of the RFID tags detected before the restart is completed. Thereafter, the data in the analyzed database is erased, and the process returns to step S201. Databases 21a and 21b erase the old analyzed data to reduce the amount of data to be stored in the server 20.

[0095] In this exemplary embodiment, the following will describe how the RFID readers 100a and 100b Figure 9 For the purpose of description, the old data to be erased is also shown in Figure 9 in databases 21a and 21b.

[0096] In step S203, the server 20 receives data that associates RFID reader ID information, RFID tag ID information, RFID tag detection time, and the RFID tag's relative position relative to a reference position. In step S204, the server 20 determines whether the RFID tag is a location RFID tag 30 or an item RFID tag 40 based on the RFID tag ID information. If the RFID tag is a location RFID tag 30, the process proceeds to step S205. On the other hand, if the RFID tag is an item RFID tag 40, the process proceeds to step S206.

[0097] In step S205, the server 20 stores the data received in step S203 in the database 21a as data for the location RFID tag 30. In step S206, the server 20 stores the data received in step S203 in the database 21b as data for the item RFID tag 40. In step S207, the server 20 checks whether a request to analyze the data in the databases 21a and 21b has been received. For example, if a predetermined amount or more of data has accumulated in the databases 21a and 21b, the server 20 performs data analysis at regular intervals or based on user instructions.

[0098] In step S208, the server 20 associates the location RFID tag 30 and the item RFID tag 40 detected at the closest time from the databases 21a and 21b among the data detected by the same RFID reader 100. Thereafter, the process proceeds to step S208.

[0099] In the method of associating data in databases 21a and 21b according to the modified example, the position RFID tag 30 and the item RFID tag 40 detected by the same RFID reader 100 at the most recent relative position are stored in association with each other. Furthermore, if the database 12 has a large storage capacity, the number of combinations of data used to associate the position RFID tag 30 and the item RFID tag 40 can be increased. For example, the item RFID tag 40 can be stored in the database 12 in association with the position RFID tag 30 detected most recently and the position RFID tag 30 detected at the most recent relative position.

[0100] Figure 9 The associated data 120 in parentheses in the database 12 is an example of data in which the position RFID tags 30 and the item RFID tags 40 that are not detected at the closest time are associated with each other.

[0101] In step S209 , the server 20 calculates the relative position of the item RFID tag 40 relative to the position RFID tag 30 associated in step S208 based on the relative position of the position RFID tag 30 relative to the reference position and the relative position of the item RFID tag 40 relative to the reference position.

[0102] As described above, the data transmitted from the RFID reader 100 to the server 20 is associated with information regarding the relative positions of the item RFID tag 40 and the position RFID tag 30 based on the common reference position (the common reference position in this exemplary embodiment is the initial position of the RFID reader 100 when it is activated). Therefore, the relative position of the item RFID tag 40 with respect to the position RFID tag 30 can be calculated through data processing by the server 20.

[0103] The common reference position is not necessarily an initial position when the RFID reader 100 is started. For example, a position where an RFID tag is detected for the first time after the RFID reader 100 is started may be used as the reference position. Figure 11 The illustrated method is merely an example of a method of transmitting information on relative positions of a plurality of RFID tags detected by the RFID reader 100 , and any other method may be used.

[0104] The RFID reader 100 includes at least a unit for detecting RFID tag ID information and information about the relative position of the RFID tag relative to a reference position. The server 20 can calculate the relative position of the location RFID tag 30 relative to the item RFID tag 40 based on the ID information and relative position information of the plurality of RFID tags transmitted from the RFID reader 100.

[0105] In step S210, the server 20 associates the ID information about the item RFID tag 40, the ID information about the location RFID tag 30, the detection time of the item RFID tag 40, the detection time of the location RFID tag 30, and the relative position of the item RFID tag 40 with respect to the location RFID tag 30. This information is then stored in the database 12.

[0106] The above process is repeated until a system end request is received (S114).

[0107] Figure 12A 、 Figure 12B and Figure 12C Each shows an example of a display displayed on the display unit 14 of the information terminal 10 according to the present exemplary embodiment. Figure 12A 、 Figure 12B and Figure 12C In the illustrated display example, position information on the management target item is displayed based on the information in the databases 11 and 12 .

[0108] The information terminal 10 transmits information such as a location name, an item name, and a time to the server 20 via an interface (not shown) of the information terminal 10 based on a user instruction. The server 20, upon receiving the information, selects data required for display on the display unit 14 from the database 12 and transmits the selected data to the information terminal 10. The information terminal 10 displays the item location information on the display 14 based on the data received from the server 20.

[0109] Figure 12A A display example is shown in which position information (ID information 30a about the position RFID tag 30) about the item RFID tag 40 relative to the north of the 1st floor of the ABC building (as a reference) at time 11 is displayed. Figure 9 The database 11 in FIG. 1 can understand that the location RFID tag 30 is installed on the north side of the first floor of the ABC building between time 10 and time 20. The server 20 selects data having the ID information of the location RFID tag 30 that matches 30a and the detection time of the item RFID tag closest to time 11 between time 10 and time 20. The server 20 transmits the item name of the item RFID tag 40 of the selected data and information about the relative position of the item RFID tag 40 with respect to the location RFID tag 30a in association so that the information terminal 10 can display the selected data on the display unit 14. Figure 12A The item location information shown.

[0110] Meanwhile, during data processing on server 20, based on the detection results of RFID reader 100a, information about items a and b is associated with the north location on the first floor of the ABC building. Based on the detection results of RFID reader 100b, information about item c is associated with the north location on the first floor of the ABC building. As described above, server 20 combines information detected by multiple RFID readers 100 to reduce missed detections of item RFID tags 40.

[0111] Figure 12B The position information (ID information 30a of the position RFID tag 30) about the item RFID tag 40 relative to the 2nd floor of the ABC building (as a reference) at time 21 is shown. Figure 9 The database 11 in FIG. 1 can be understood that the location of the ID information 30a of the RFID tag 30 is located at the 2nd floor of the ABC building at time 20. Therefore, Figure 12B The display in uses the detection results of the location RFID tag 30 and the item RFID tag 40 detected at time 20 or later.

[0112] As described above, in the case of moving the location RFID tag 30, after moving the location RFID tag 30, the user only needs to register the new location name and installation time in the database 11. Therefore, the user can move the use place of the location detection system 2 through simple operations.

[0113] Furthermore, database 12 stores the detection time of location RFID tags 30 in addition to the detection time of item RFID tags 40. Therefore, even if a user installs a location RFID tag 30 at a new location and, some time later, registers the name of the new location of the location RFID tag 30 and its installation time in database 11, item location information from past data in database 12 can be retrospectively displayed. Storing the detection time of the location RFID tag 30 in database 12 is effective even when the location RFID tag 30 is moved.

[0114] Figure 12C The position information of the item RFID tag 40 relative to the east side of the first floor of the ABC building (as a reference) at time 31 (ID information 30b of the position RFID tag 30) is shown. Figure 9 As shown in the database 11, the location of the ID information 30b of the RFID tag 30 is installed at the time 10 on the 1st floor east of the ABC building. Therefore, Figure 12C The display in uses the detection results of the position RFID tag 30 and the item RFID tag 40 detected at or after time 10, among the data of the item RFID tag 40 associated with the position RFID tag 30 of the ID information 30b.

[0115] The following describes the advantages of the control method according to this exemplary embodiment, where user A of RFID reader 100a installs location RFID tag 30a, and user B of RFID reader 100b installs location RFID tag 30b. Since user B has already installed location RFID tag 30b on the east side of the 1st floor of the ABC building at time 31, user A can use RFID reader 100a to detect the relative positions of location RFID tag 30b and items b and c at time 31. Therefore, it can be understood that as more users use location detection system 2 and install location RFID tags 30, detecting the positions of item RFID tags 40 becomes easier.

[0116] In the position detection system 2 according to the modified example, the information terminal 10 is not used, the RFID reader 100 includes the display unit 14, and the server 20 transmits data to the RFID reader 100 to display the data on the display unit 14 of the RFID reader 100. In addition, instead of the RFID reader 100 and the server 20 communicating directly, the RFID reader 100 and the information terminal 10 may be connected so that the RFID reader 100 and the server 20 communicate through the information terminal 10. In addition, according to the present exemplary embodiment, instead of using the server 20, the information terminal 10 may perform data processing of the server 20.

[0117] As described above, the RFID reader 100 according to this exemplary embodiment includes a unit for detecting ID information about an RFID tag and information about the relative position of the RFID tag relative to a reference position. The server 20 can calculate the relative position of the item RFID tag relative to the location RFID tag based on the information transmitted from the RFID reader 100.

[0118] Third Exemplary Embodiment

[0119] Figure 13is a system diagram according to the third exemplary embodiment. The system according to this exemplary embodiment uses an RFID reader 200 in which the RFID reader 100 and information terminal 10 according to the first exemplary embodiment are integrated. This exemplary embodiment differs from the first exemplary embodiment in that database 12 stores only the ID information about the item RFID tags 40 in association with information about their relative positions relative to a reference position. Each configuration similar to that in the first exemplary embodiment is given the same reference number, and redundant description thereof is omitted.

[0120] Figure 13 The RFID reader 200 in FIG. 1 includes, in addition to the functions of the RFID reader 100 according to the first exemplary embodiment, the functions of the display unit 14 and the databases 11 and 12. In contrast, the communication unit 103 is not included.

[0121] The position detection system 3 according to the present exemplary embodiment includes only one position RFID tag 30, and it is not necessary to store the ID information about the position RFID tag 30 in association with the ID information and relative position information about the item RFID tag 40 in the database 12. In addition, it is not necessary to store the position RFID tag 30 in association with the location name in the database 11. In order to distinguish between the position RFID tag 30 and the item RFID tag 40, only the ID information about the position RFID tag 30 is stored in the database 11.

[0122] Furthermore, the position detection system 3 can only display the latest position information detection result on the display unit 14, and does not need to store the detection time of the item RFID tag 40 in association with the database 12. The latest detection result of the item RFID tag 40 is updated and stored for each ID.

[0123] Figure 14 is a flowchart showing the processing performed by the RFID reader 200 according to the present exemplary embodiment. This flowchart is similar to the flowchart according to the first exemplary embodiment. Figure 4 The difference between the flowchart in FIG. 1 and FIG. 2 is that after the position RFID tag is detected in step S105, the item RFID tag data is updated. Another difference is that in step S314, only the ID information about the item RFID tag 40 and the information about the relative position of the item RFID tag 40 with respect to the position RFID tag 30 are stored. Figure 4 In this way, the computing unit 101 of the RFID reader 200 executes Figure 14 The steps in the flowchart.

[0124] Under the control according to this exemplary embodiment, the RFID reader 200 does not update the RFID tag data until the position RFID tag 30 is detected in step S105. Therefore, in step S301, the display unit 14 displays a display prompting the user to approach the position RFID tag until the position RFID tag 30 is detected for the first time.

[0125] Furthermore, if the position RFID tag 30 is not detected within a predetermined period of time from when the RFID reader 100 starts control, control is performed to prompt the user to detect the position RFID tag 30 using the display on the display unit 14 or the buzzer. This can also be performed in the case of the first and second exemplary embodiments.

[0126] In step S314, the RFID reader 200 updates the ID information about the item RFID tag 40 and the relative position of the item RFID tag 40 with respect to the position RFID tag 30a in the database 12. The display unit 14 displays the relative position of the item RFID tag with respect to the position RFID tag 30a.

[0127] The above process is repeated until a system end request is received (S114).

[0128] As described above, in the position detection system 3 according to this exemplary embodiment, it is not necessary to store the ID information of the position RFID tag 30 and the detection time of the item RFID tag 40, thereby further reducing the required data capacity of the database 12. Therefore, this system is applicable even when the storage unit 102 of the RFID reader 200 has a small data capacity. In addition, since communication with the information terminal 10 or the server 20 is not required, the communication unit 103 is not required, thereby reducing the cost of the RFID reader 200.

[0129] According to the present exemplary embodiment, only the ID information about the item RFID tag 40 and the information about the relative position of the item RFID tag 40 with respect to the position RFID tag 30 are data to be managed in the database 12. Even in this case, it is possible to manage the position information of the management target of the additional RFID tag which can be used indoors and outdoors easily at low cost and exists over a large area.

[0130] [Description of location RFID tags and item RFID tags]

[0131] Figure 15A and Figure 15B is a diagram illustrating RFID tags that are examples of position RFID tags 30 and item RFID tags 40 that can be used in the first to third exemplary embodiments.

[0132] Figure 15A The position RFID tag 30 shown is used as a reference position for managing position information on an item to which the item RFID tag 40 is attached. The holding member 32 is an outer package for holding the position RFID tag 30.

[0133] like Figure 15B As shown, the item RFID tag 40 is an RFID tag that is attached to an item.

[0134] At the same time, the location RFID tag 30 and the item RFID tag 40 are RFID tags that can communicate with the RF control unit 110 of the RFID reader 100 and operate based on the same principle. Therefore, in the location information management methods according to the first to third exemplary embodiments, there is no need to provide separate detection circuits for item detection and detection circuits for position detection, thereby achieving advantages such as reduced cost, size, and power consumption of the RFID reader 100. [Method of Improving Item Position Detection Accuracy]

[0135] Figure 6 and Figure 7 are flowcharts each describing a control process of a method for further improving the accuracy of position information about an item RFID tag 40. In the first to third exemplary embodiments, these processes are executed as needed when the RFID reader detects a position RFID tag. The computing unit of the RFID reader executes a program stored in the storage unit, thereby executing Figure 6 and Figure 7 Steps in the flowchart.

[0136] If the RFID reader 100 detects the location RFID tag 30, it starts Figure 6 in the control.

[0137] In step S401, the RFID reader 100 stores the detected ID information about the location RFID tag 30 in the storage unit 102. In step S402, the RFID reader 100 reduces the level of the RF output (Tx signal) of the RF control unit 110 of the RFID reader 100. In step S403, the RFID reader 100 determines whether communication with the location RFID tag 30 stored in step S401 has been successful again. If communication is successful, the process proceeds to step S402, and the RF output of the RFID reader is further reduced, and the process is repeated until communication is no longer successful in step S403. On the other hand, if communication is unsuccessful, the process proceeds to step S404.

[0138] In step S404, the RFID reader 100 stores the lowest RF output value at which communication with the location RFID tag 30 was successful, in association with the ID information of the location RFID tag 30. In step S405, the RFID reader 100 determines whether the RF output value is the lowest RF output value within a predetermined period of time in the history of successful communications with location RFID tags 30 with the same ID information. If, in step S405, the RF output value is the lowest RF output value, the process proceeds to step S108. In step S108, the ID information regarding the detected location RFID tag 30 is stored in the storage unit 102, and the process proceeds to step S112. In step S112, the relative position is set to 0. On the other hand, if, in step S405, the RF output value is not the lowest RF output value, the location RFID tag detection result is invalid, and the relative position is not set to 0.

[0139] exist Figure 6 In the control flow chart, when the RFID reader 100 successfully detects the position RFID tag 30 at low RF output, it is determined that the position RFID tag 30 and the RFID reader 100 are close to each other. Then, at this timing, the relative position is set to 0 so that the data when the position RFID tag 30 is successfully detected at low RF output is associated with the detection data of the item RFID tag 40.

[0140] Similarly, if the RFID reader 100 detects the location RFID tag 30, it initiates Figure 7 in the control.

[0141] In step S504, the RFID reader 100 stores the strength of the RF input (Rx signal) received by the RF control unit 110 of the RFID reader 100 in the storage unit 102. In step S505, the RFID reader 100 determines whether the RF input is the highest RF input value within a predetermined period of time in the history of successful communication with the position RFID tag 30 of the same ID information. In step S505, if the RF input is the highest RF input value, the process proceeds to step S108. In step S108, the ID information about the detected position RFID tag 30 is stored in the storage unit 102, and the process proceeds to step S112. In step S112, the relative position is set to 0. On the other hand, in step S505, if the RF input is not the highest RF input value, the position RFID tag detection result is invalid, and the relative position is not set to 0.

[0142] exist Figure 7In the control flow chart, when the RFID reader 100 successfully detects the position RFID tag 30 under high RF input, it is determined that the position RFID tag 30 and the RFID reader 100 are close to each other. Then, at this timing, the relative position is reset so that the data of the position RFID tag 30 successfully detected under high RF input is associated with the data detected on the item RFID tag 40.

[0143] In the article location management system according to each exemplary embodiment of the present invention, the location RFID tag 30 is used as a reference location. Therefore, in particular, the location RFID tag 30 is performed Figure 6 and Figure 7 The control method shown improves the accuracy of the position information to be managed.

[0144] In addition, the item RFID tag 40 is subjected to a similar Figure 6 and Figure 7 The control in can improve the accuracy of the location information to be managed.

[0145] As in the second exemplary embodiment, in the case where the server 20 performs data processing, data on the RF input strength or RF output strength of the RFID reader 100 is stored in association with the databases 21a and 21b of the server 20. This enables the server 20 to perform data processing in association with the RFID reader 100. Figure 6 and Figure 7 Similar controls to those in . Figure 6 and Figure 7 The illustrated method of improving the accuracy of position information is also applicable to the case of the second exemplary embodiment.

[0146] Figure 8 The method of using the charging device 300 as the location RFID tag 30 by including the function of the location RFID tag 30 in the charging device 300 of the RFID reader 100 is shown. The connector 301 is used to connect the charging device 300 with the RFID reader 100.

[0147] Using the charging device 300, the location RFID tag 30 can be detected at a short distance while charging the RFID reader 100. In particular, by combining Figure 6 and Figure 7 The control in increases the accuracy of the location information about the RFID reader 100.

[0148] [Control of Antenna Radiation Directivity]

[0149] Figure 16A 、 Figure 16B 、 Figure 16C and Figure 16DThe antenna unit 115 having a radiation directivity control function that can be used in the first to third exemplary embodiments is shown. The substrates 1101 and 1102 are overlapped in the order of -Z direction along the Z axis in the thickness direction of the substrates 1101 and 1102.

[0150] Figure 16A The front surface of substrate 1101 is shown. Four antenna elements 1103 are arranged so that the extension direction of antenna elements 1103 is changed by 90 degrees along the X-axis and Y-axis respectively, so that the open ends do not overlap, and the feed ends, which are the ends on the opposite sides of the open ends, are connected to through-holes 1104. The extension direction of the open ends can be opposite, or the element shape can be curved.

[0151] Figure 16B The back side of the substrate 1101 is shown. Four vias 1104 pass through the substrate 1101 and connect to four pads 1105.

[0152] Figure 16C The front surface of the substrate 1102 is shown. Four pads 1106 are connected to a ground 1107 and are respectively connected to four RF lines 1108. The pads 1105 and 1106 are respectively in contact with the surface of a metal pad as a conductive portion (not shown) for conduction.

[0153] The four RF lines 1108 pass through respective four RF switches 1109 ( 1109 a to 1109 d ) and a shared RF line 1110 , and are connected to a transmission / reception unit 1111 (coupler 114 ).

[0154] One end of each RF switch 1109 is connected to each RF line 1108, and the other end thereof is connected to the RF line 1110, and the RF switch 1109 controls whether to short-circuit or open-circuit. Therefore, when the RF switch 1109 is in the short-circuit state, the RF signal can pass between the transmission / reception unit 1111 and the antenna element 1103, while when the RF switch 1109 is in the open-circuit state, the RF signal cannot pass between the transmission / reception unit 1111 and the antenna element 1103.

[0155] Figure 16D The rear surface of substrate 1102 is shown. Ground 1112 is arranged on the entire surface, except for the area overlapping with pad 1106, and is electrically connected to ground 1107 through multiple vias (not shown) of substrate 1102. The line width and thickness of RF lines 1108 and 1110 are determined based on the layer structure and dielectric constant of substrate 1102 to obtain approximately 50 ohms at the RF signal frequency.

[0156] In the figure, the four pads 1106 are defined as A, B, C, and D in a counterclockwise order from the upper right corner. The total electrical lengths of the RF lines connecting A, B, C, D and the transmit / receive unit 1111 are represented by a, b, c, and d, respectively. The four RF lines 1108 are arranged in a curved pattern to satisfy the relationships b = a + λ / 4, c = b + λ / 4, and d = c + λ / 4, and do not overlap with the ground 1107. Each of the four RF lines 1108 has a phase difference of λ / 4, or approximately 90 degrees. The direction of rotation and the method of achieving the phase difference can be any direction and method, and phase shifters can be used instead of line lengths.

[0157] The RF signal transmitted and received by the antenna unit 115 is a circularly polarized wave when the RF signal is a composite wave of four antenna elements 1103, and is a linearly polarized wave when the RF signal is a composite wave of two opposing antenna elements 1103.

[0158] Figure 17A 、 Figure 17B and Figure 17C The figure shows the radiation characteristics of the antenna resonating at 920 MHz in this exemplary embodiment. Substrates 1101 and 1102 each have a thickness of 1 mm and a relative permittivity of 4.3. The distance between substrates 1101 and 1102 is 7 mm, and the element length of the inverted F antenna is approximately λ / 4. Furthermore, the RF lines each have a line width of 1.6 mm and a line width of 35 μm.

[0159] Figure 17A The radiation characteristics are shown in the case where all the RF switches 1109 a to 1109 d are short-circuited, and an RF signal of a circularly polarized wave having main directivity in the +Z direction is emitted.

[0160] Figure 17B The radiation characteristics are shown in the case where the RF switches 1109 a and 1109 c are short-circuited and the RF switches 1109 b and 1109 d are open, and RF signals of linearly polarized waves are emitted in the +X and −X directions.

[0161] Figure 17C The radiation characteristics are shown in the case where the RF switches 1109 b and 1109 d are short-circuited and the RF switches 1109 a and 1109 c are open, and RF signals of linearly polarized waves are transmitted in the +Y and −Y directions.

[0162] Using this technology, RFID tags located in the X- and Y-axis directions, which cannot be read by circularly polarized RF signals emitted only in the +Z direction, can be made readable by changing their directionality. Furthermore, location information regarding items with RFID tags present over a large area can be detected. RFID reader 100 detects RFID tags while changing the radiation characteristics of antenna unit 115 in multiple directions. Antenna unit 115 is suitable for use in the first through third exemplary embodiments.

[0163] Other embodiments

[0164] The first to third exemplary embodiments described above can be implemented in combination as needed. For example, an RFID reader including the display unit according to the third exemplary embodiment does not necessarily need to display the location information of the management target item on the display unit of the RFID reader, but can transmit this information to a server or information terminal. Alternatively, the user can select whether to display the information on the RFID reader or transmit the information to the server or information terminal through operation.

[0165] The present invention is not limited to the above exemplary embodiments, and can be modified or altered in various ways without departing from the spirit and scope of the present invention. Therefore, the following claims are attached to disclose the scope of the present invention.

[0166] This application claims the benefit of Japanese Patent Application No. 2020-037063, filed on March 4, 2020, which is hereby incorporated by reference herein in its entirety.

Claims

1. A communication device, comprising: power supply; a detection unit configured to detect a wireless device; a storage unit configured to store identification information about the wireless device; a calculation unit configured to calculate a first relative position of a second wireless device with respect to a first wireless device to be used as a reference in identifying a position based on an amount of movement of the communication apparatus, the second wireless device being a device different from the first wireless device; as well as an associating unit configured to associate the first relative position, the identification information about the second wireless device, and the identification information about the first wireless device, Here, when the position of the communication device when the power of the communication device is turned on is defined as the initial position, in a case where the detection unit detects the second wireless device in a state where the first wireless device is not detected after detecting the initial position, the storage unit stores a second relative position of the second wireless device with respect to the initial position, and in a case where the detection unit detects the first wireless device after detecting the second wireless device, the storage unit stores a third relative position of the first wireless device with respect to the initial position, and then the calculation unit calculates the first relative position based on the second relative position indicating the movement amount of the communication device and based on the third relative position.

2. The communication device according to claim 1, further comprising: a determining unit configured to determine whether the wireless device detected by the detecting unit is a first wireless device, The storage unit stores the identification information about the detected wireless device as the identification information about the first wireless device when the determination unit determines that the detected wireless device is the first wireless device.

3. The communication device according to claim 1, wherein The associating unit further associates information indicating a detection time of the wireless device. 4 . The communication device according to claim 1 , further comprising a transmitting unit configured to transmit the information associated by the associating unit to an information terminal. 5 . The communication apparatus according to claim 1 , further comprising a display unit configured to display position information about the second wireless device based on the calculated first relative position. The communication device according to claim 1 , wherein: The communication device is a radio frequency identification (RFID) reader, the wireless device is an RFID tag, and the detection unit detects the wireless device using RFID.

7. The communication device according to claim 1, wherein The detection unit detects the wireless device using an antenna configured to change radiation directivity of radio waves.

8. An information processing device, comprising: a receiving unit configured to receive, from a communication device that detects a wireless device, identification information about the detected wireless device and information about a relative position of the detected wireless device with respect to a reference position; a calculating unit configured to calculate, based on the information received by the receiving unit, a first relative position of the second wireless device relative to the first wireless device using information about a relative position of the first wireless device to be used as a reference in identifying the position relative to a reference position and information about a relative position of a detected second wireless device different from the first wireless device relative to the reference position; as well as an associating unit configured to associate the first relative position, the identification information about the second wireless device, and the identification information about the first wireless device, Here, when the position of the communication device when the power of the communication device is turned on is defined as the reference position, in a case where the second wireless device is detected in a state where the first wireless device is not detected after the reference position is detected, the receiving unit receives a second relative position of the second wireless device with respect to the reference position, and in a case where the first wireless device is detected after the second wireless device is detected, the receiving unit receives a third relative position of the first wireless device with respect to the reference position, and then calculates the first relative position based on the second relative position and the third relative position calculation unit.

9. The information processing device according to claim 8, in, The receiving unit receives information indicating the time when the communication apparatus detects the wireless device, and The calculation unit selects a wireless device to be used as a relative position calculation target based on a detection time of the first wireless device and a detection time of a wireless device different from the first wireless device. 10 . The information processing apparatus according to claim 8 , further comprising a transmitting unit configured to transmit the information about the first relative position to an information terminal. 11 . The information processing apparatus according to claim 8 , further comprising a display unit configured to display position information about a wireless device represented by the identification information received by the reception unit based on the first relative position.

12. The information processing apparatus according to claim 8, wherein: The wireless device is an RFID tag, the communication means that detects the wireless device is an RFID reader, and the receiving unit receives information on the wireless device detected by the communication means using RFID.

13. A location information management method, the method comprising: detecting the wireless device via the communication device; storing identification information about the wireless device; calculating a first relative position of a second wireless device with respect to a first wireless device to be used as a reference in identifying a position based on an amount of movement of the communication apparatus, the second wireless device being a device different from the first wireless device; as well as associating the first relative position, the identification information about the second wireless device, and the identification information about the first wireless device, Here, when the position of the communication device when the power of the communication device is turned on is defined as an initial position, if a second wireless device is detected in a state where the first wireless device is not detected after detecting the initial position, a second relative position of the second wireless device with respect to the initial position is stored, and if the first wireless device is detected after detecting the second wireless device, a third relative position of the first wireless device with respect to the initial position is stored, and the first relative position is calculated based on the second relative position indicating the amount of movement of the communication device and based on the third relative position.

14. A location information management method, the method comprising: receiving, from a communication device that detects a wireless device, identification information about the detected wireless device and information about a relative position of the detected wireless device with respect to a reference position; calculating, based on the received information, a first relative position of the second wireless device relative to the first wireless device using information about a relative position of the first wireless device to be a reference in identifying the position relative to the reference position and information about a relative position of a second wireless device detected that is different from the first wireless device relative to the reference position; as well as associating the first relative position, the identification information about the second wireless device, and the identification information about the first wireless device, Here, when the position of the communication device when the power of the communication device is turned on is defined as a reference position, if a second wireless device is detected after detecting the reference position but the first wireless device is not detected, a second relative position of the second wireless device relative to the reference position is received, and if the first wireless device is detected after detecting the second wireless device, a third relative position of the first wireless device relative to the reference position is received, and the first relative position is calculated based on the second relative position and the third relative position. 15 . A non-transitory computer-readable storage medium storing a program for causing a computer to operate as the communication device according to claim 1 . 16 . A non-transitory computer-readable storage medium storing a program for causing a computer to operate as the information processing apparatus according to claim 8 .

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