Wireless tag communication device and program

Abstract

To provide a wireless tag communication device and a program capable of identifying the location of an RFID tag.SOLUTION: According to an embodiment, a wireless tag communication device includes a communicator, a position detection sensor, a memory, and a processor. The communicator communicates with a target wireless tag. The position detection sensor detects information indicating its self-position. The memory stores the self-position identified from detection information of the position detection sensor and a read result of the wireless tag read by the communicator in association with each other. The processor estimates the position of the wireless tag when three or more wireless tag read results that are consecutive at a predetermined interval stored in the memory are obtained.SELECTED DRAWING: Figure 2

Description

[Technical field]

[0001] An embodiment of the present invention relates to a radio tag communication device and a program. [Background technology]

[0002] Conventionally, there is a wireless tag communication device that aims to find an RFID tag (hereinafter, also referred to as a wireless tag) in an unspecified location. The wireless tag communication device communicates with the RFID tag while changing the position and orientation of the antenna by the operation of an operator. The conventional wireless tag communication device estimates the direction in which the RFID tag to be searched for is located based on the communication state with the RFID tag to be searched for.

[0003] Conventional radio tag communication devices notify an operator of the direction in which an RFID tag is located by displaying on a display a guidance screen including an estimation result of the direction in which an RFID tag is located. The operator searches for an RFID tag or an item to which an RFID tag is attached while moving in the direction displayed on the display. However, conventional radio tag communication devices only notify the direction in which an RFID tag is located, and do not notify the position of the RFID tag being searched for. For this reason, conventional radio tag communication devices have a problem in that operators who are unfamiliar with the operation take a long time to find an RFID tag. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] JP 2011-237941 A Summary of the Invention [Problem to be solved by the invention]

[0005] In order to solve the above-mentioned problems, an object of the present invention is to provide a radio tag communication device and a program capable of identifying the location of an RFID tag. [Means for solving the problem]

[0006] According to an embodiment, a wireless tag communication device includes a communicator, a position detection sensor, a memory, and a processor. The communicator communicates with a target wireless tag. The position detection sensor detects information indicating the self-position. The memory stores the self-position determined from the detection information of the position detection sensor in association with the reading result of the wireless tag read by the communicator. The processor estimates the position of the wireless tag when three or more consecutive wireless tag reading results stored in the memory are obtained at a predetermined interval. [Brief description of the drawings]

[0007] [Figure 1] FIG. 1 is an external view showing an example of the external configuration of a radio tag communication device according to an embodiment. [Diagram 2] FIG. 2 is a block diagram illustrating a first example of the configuration of a control system in the wireless tag communication device according to the embodiment. [Diagram 3] FIG. 3 is a block diagram illustrating a second example of the configuration of the control system in the wireless tag communication device according to the embodiment. [Figure 4] FIG. 4 is a diagram showing an example of positional relationships when the wireless tag communication device according to the embodiment reads RFID tags to be searched for at three different positions. [Diagram 5] FIG. 5 is a diagram showing an example of a determination table stored in a memory of the wireless tag communication device according to the embodiment. [Figure 6] FIG. 6 is a graph for the wireless tag communication device according to the embodiment to estimate an angle based on the ratio of the distance between two positions to the difference in distance from the two positions to the target tag. [Figure 7] FIG. 7 is a diagram showing a change in phase in the read result when the RFID tag communication unit 23 of the RFID tag communication device according to the embodiment continuously reads target tags. [Figure 8] FIG. 8 is a diagram showing an example in which the read results (phases) obtained by the RFID tag communication device according to the embodiment reading the target tag at a predetermined read cycle are plotted. [Figure 9]FIG. 9 is a diagram showing an example of plotting the read results (phase) when there is a period during which the wireless tag communication device according to the embodiment cannot read the target tag. [Figure 10] FIG. 10 is a flowchart for explaining an example of an operation of a first tag search process by the wireless tag communication device according to the embodiment. [Figure 11] FIG. 11 is a flowchart for explaining an example of operation of a second tag search process by the wireless tag communication device according to the embodiment. [Figure 12] FIG. 12 is a flowchart for explaining an operation example of a third tag search process by the wireless tag communication device according to the embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0008] Hereinafter, embodiments will be described with reference to the drawings. First, the configuration of a radio tag communication device (radio tag reader) 1 according to the embodiment will be described. Fig. 1 is a diagram showing an example of the external configuration of a radio tag communication device 1 according to an embodiment. The radio tag communication device 1 shown in Fig. 1 is a handheld device that is operated by an operator while being held in his / her hand. The radio tag communication device 1 shown in Fig. 1 is used as a search device that searches for an RFID tag or an article to which an RFID tag is attached, for example.

[0009] The wireless tag communication device 1 according to the embodiment is a device that communicates with an RFID tag (wireless tag). The wireless tag communication device 1 is a wireless tag reading device that reads tag information recorded in an RFID tag by communicating with the RFID tag. The wireless tag communication device 1 estimates the location of the RFID tag from the RFID tag reading result. The wireless tag communication device 1 displays a guidance screen on a display device that shows information related to the estimated location of the RFID tag.

[0010] The RFID tag is a wireless communication device that operates by radio waves (output signals) from the wireless tag communication device 1. The RFID tag has a processor, a memory, a communication circuit, an antenna, etc. In response to a read command from the wireless tag communication device 1, the RFID tag outputs a response signal including tag information recorded in its own memory. For example, the RFID tag is attached to an item such as a product or a part. The RFID tag attached to the item has tag information including information identifying the item recorded in its internal memory.

[0011] The radio tag communication device 1 according to the embodiment is operated by an operator. The radio tag communication device 1 is a device that communicates with a specified RFID tag while moving. For example, the radio tag communication device 1 is a handheld device that the operator holds in his / her hand and operates while moving. The radio tag communication device 1 may also be mounted on a moving object operated by the operator.

[0012] The wireless tag communication device 1 according to the embodiment reads an RFID tag attached to an item while changing its position and orientation by an operation of an operator. For example, the wireless tag communication device 1 is operated as a search device for searching for an item with an RFID tag attached within a predetermined area (search range) such as a warehouse or a store. The wireless tag communication device 1 as a search device continuously reads the RFID tag to be searched while changing its position by an operation of an operator.

[0013] The wireless tag communication device 1 reads tag information recorded in an RFID tag by receiving a response signal from the RFID tag present within a reading area (reading range). Furthermore, the wireless tag communication device 1 also obtains information such as an RSSI value and a phase value from the response (received) signal from the RFID tag. The wireless tag communication device 1 stores the tag information, RSSI value, and phase value obtained from the received signal, together with information such as the position and orientation of the device itself, in a memory as a reading result.

[0014] 1, the radio tag communication device 1 is composed of a reader device (base device) 10 and an information terminal device 13 serving as a user interface. The reader device 10 may be provided as the radio tag communication device 1. In this case, the radio tag communication device 1 serving as the reader device 10 is operated with the information terminal device 13 serving as an external device set as a user interface.

[0015] The reader device 10 includes a housing in which an RFID tag interface having an antenna and a communication control circuit is installed. In the reader device 10, the antenna is installed so that its directivity is strongest in the direction of the arrow a shown in Fig. 1. Here, the direction of the arrow a is assumed to be the front (forward) direction of the wireless tag communication device 1. Also, the front direction of the wireless tag communication device 1 is assumed to be the orientation of the antenna.

[0016] The reader device 10 has a gripping unit 11 and a holding unit 12 in addition to a control system configuration described later. The gripping unit 11 is a part that is held by an operator. The holding unit 12 is configured by a jig that holds an information terminal device 13. The holding unit 12 holds the information terminal device 13 so that the display screen of a display 14 of the information terminal device 13 faces the operator holding the gripping unit 11. The wireless tag communication device 1 is operated by an operator holding the gripping unit 11 with the information terminal device 13 set in the holding unit 12.

[0017] The information terminal device 13 has a display unit 14 and an input unit 15. The display unit 14 and the input unit 15 are, for example, display devices with touch panels. When the information terminal device 13 is set in the holding unit 12 of the reader device 10, an operator can view a screen displayed by the display unit 14. When the information terminal device 13 is set in the holding unit 12 of the reader device 10, an operator inputs an operation instruction to the input unit 15.

[0018] The radio tag communication device 1 continuously reads RFID tags while being operated by an operator. For example, the operator changes the position of the radio tag communication device 1 (the position of the device itself) equipped with an antenna by moving while holding the grip part 11. The radio tag communication device 1 repeatedly reads RFID tags within a reading area set by the direction of the antenna and the strength of the radio waves output from the antenna while estimating the position of the device itself.

[0019] The wireless tag communication device 1 identifies (estimates) its own position using a self-estimation technique. For example, the wireless tag communication device 1 identifies its own position (position of the communicator) by a self-position estimation technique used in AR (Augmented Reality) technology based on an image captured by a camera. However, the technique and configuration for identifying the position of the wireless tag communication device 1 are not limited to a specific one as long as the device can identify its own position even indoors.

[0020] The wireless tag communication device 1 determines whether or not a search target RFID tag is present in a read area based on the RFID tag read results in the read area set by the antenna direction and the strength of the radio waves output from the antenna. For example, the wireless tag communication device 1 stores in memory the read results of the RFID tag to be searched in a plurality of read areas based on the positions of the plurality of moved devices. For example, the wireless tag communication device 1 stores in memory information such as tag information, phase value, antenna direction, and output value as the RFID tag read results. The wireless tag communication device 1 stores in memory the read results including the tag information of the search target RFID tag as the read result of a specific RFID tag in association with information indicating its own position (position information).

[0021] The wireless tag communication device 1 estimates the location of the RFID tag to be searched for based on the read results at multiple different self-positions stored in the memory. For example, the wireless tag communication device 1 estimates the location (tag location) of the RFID tag to be searched for based on the read results of the RFID tag to be searched for at three or more different self-positions at a predetermined interval.

[0022] Next, the configuration of a control system in the wireless tag communication device 1 according to the embodiment will be described. FIG. 2 is a block diagram showing a first example of the configuration of a control system in the wireless tag communication device 1 according to the embodiment. In the exemplary configuration shown in FIG. 2, the RFID tag communication device 1 includes a processor 21, a memory 22, a RFID tag communication unit 23, a sensor 24, a communication interface (I / F) 25, a camera 26, a display 14, and an input device 15.

[0023] The processor 21 controls each unit. The processor 21 includes an arithmetic circuit such as a CPU. The processor 21 executes programs to control each unit and perform various data processing. The processor 21 may also include an internal memory. The processor 21 executes programs stored in the memory 22 or the like to perform various processes.

[0024] The memory 22 includes various types of memories. For example, the memory 22 includes memories such as ROM, RAM, and NVM. The ROM is a non-volatile memory that cannot be rewritten. The ROM stores programs to be executed by the processor 21. The RAM is a volatile memory that temporarily stores data. The RAM operates as a working memory or a buffer memory.

[0025] The NVM of the memory 22 is a rewritable non-volatile memory. The memory 22 saves information such as control information, setting information, and processing results in the NVM. The memory 22 also stores in the NVM various programs for the processor 21 to execute each process described below. For example, the memory 22 stores in the NVM an operation assistance program that outputs information for assisting an operator in operating the housing. The memory 22 also stores in the NVM an evaluation reference value for the operation assistance program to evaluate the operation of the housing.

[0026] The wireless tag communication unit 23 is a communication device constituting an RFID interface that communicates with an RFID tag. The wireless tag communication unit 23 is, for example, a communication device having a communication control circuit and an antenna. However, the wireless tag communication unit 23 may be configured as a connection interface that connects to an external antenna.

[0027] In the wireless tag communication unit 23, the communication control circuit includes a control circuit for communicating with the RFID tag via the antenna. The communication control circuit causes the antenna to emit a transmission signal (radio wave) supplied from the processor 21 at a set output value. The antenna outputs the transmission signal supplied from the communication control circuit as a radio wave that can be received by the RFID tag. The wireless tag communication unit 23 sets a range (read area, read range) in which the RFID tag can respond based on the orientation of the antenna and the output value of the radio wave output from the antenna.

[0028] In addition, in the wireless tag communication unit 23, the communication control circuit not only outputs a transmission signal to the antenna, but also supplies a signal received by the antenna as received data to the processor 21. The communication control circuit receives a response signal from the RFID tag by the antenna, processes the response signal (received signal) received by the antenna, and supplies it to the processor 21. For example, the communication control circuit supplies the processor 21 with tag information included in the received signal from the RFID tag, and an RSSI value and a phase value indicating the strength of the received signal.

[0029] The sensor (sensor group) 24 includes a sensor that detects the position or a change in position of the wireless tag communication device 1. For example, the sensor 24 is an acceleration sensor, a gyro sensor, or a geomagnetic (direction) sensor. The sensor 24 may include a plurality of types of sensors. The sensor 24 may also include a position detection sensor that detects the position of the wireless tag communication device 1. The sensor 24 is an example of a position detection sensor that detects information indicating its own position (position of the communicator).

[0030] The communication I / F 25 is an interface for communicating with an external device. The communication I / F 25 is an interface for communicating with a higher-level device 19 such as a server. The communication I / F 25 may be an interface for wired communication or an interface for wireless communication.

[0031] The camera 26 captures an image. The capturing direction of the camera 26 changes depending on the orientation of the wireless tag communication device 1. For example, the capturing direction of the camera 26 may be set to match the orientation of the antenna of the wireless tag communication unit 23. The image captured by the camera 26 is used to estimate the position of the wireless tag communication device 1 (the position of the device itself). The camera 26 is an example of a position detection sensor that detects information indicating its own position (the position of the communicator). For example, the wireless tag communication device 1 identifies its own position (the position of the communicator) based on the image captured by the camera 26 by a self-position estimation technique used in AR (Augmented Reality) technology.

[0032] The display 14 and input device 15 included in the information terminal device 13 are connected to the processor 21 via an internal interface. The display 14 is a device that displays information. For example, the display 14 displays a display screen instructed by the processor 21. The input device 15 is a device that allows an operator to input operation instructions and the like. The input device 15 supplies the processor 21 with information indicating the contents of the instructions given by the operator.

[0033] The radio tag communication device 1 has a power source that supplies power for operation. In a handheld type radio tag communication device 1, for example, a rechargeable battery (secondary battery) is provided as the power source. The battery supplies each part of the radio tag communication device 1 with power to operate the parts. The radio tag communication device 1 may also be configured such that the camera 26 is replaced with a device for identifying the position of the device itself.

[0034] Next, the configuration of a control system in the wireless tag communication device 1 according to the embodiment will be described. FIG. 3 is a block diagram showing a second example of the configuration of the control system in the wireless tag communication device 1 according to the embodiment. 3, a reader device 10 serving as the wireless tag communication device 1 is connected to an information terminal device 13 serving as an external device. The reader device 10 serving as the wireless tag communication device 1 includes a processor 21, a memory 22, a wireless tag communication unit 23, and an interface (I / F) 26.

[0035] The processor 21 controls each unit. The processor 21 includes an arithmetic circuit such as a CPU. The processor 21 executes programs to control each unit and perform various data processing. The processor 21 may also include an internal memory. The processor 21 executes programs stored in the memory 22 or the like to perform various processes.

[0036] The memory 22 includes various kinds of memories. For example, the memory 22 includes memories such as ROM, RAM, and NVM. The ROM is a non-volatile memory that cannot be rewritten. The ROM stores programs executed by the processor 21. The RAM is a volatile memory that temporarily stores data. The RAM operates as a working memory or a buffer memory. The NVM is a non-volatile memory that can be rewritten. The NVM saves information such as control information, setting information, and processing results. The NVM of the memory 22 stores various programs for the processor 21 to execute each process described later.

[0037] The wireless tag communication unit 23 is a communication device that constitutes an RFID interface that communicates with an RFID tag. The wireless tag communication unit 23 is a communication device that has a communication control circuit and an antenna. However, the wireless tag communication unit 23 may be configured as a connection interface that connects to an external antenna.

[0038] In the wireless tag communication unit 23, the communication control circuit includes a control circuit for communicating with the RFID tag via the antenna. The communication control circuit causes the antenna to emit a transmission signal (radio wave) supplied from the processor 21 at a set output value. The antenna outputs the transmission signal supplied from the communication control circuit as a radio wave that can be received by the RFID tag. The wireless tag communication unit 23 sets a range (read area) in which the RFID tag can respond based on the orientation of the antenna and the output value of the radio wave output from the antenna.

[0039] In addition, in the wireless tag communication unit 23, the communication control circuit not only outputs a transmission signal to the antenna, but also supplies a signal received by the antenna as received data to the processor 21. The communication control circuit receives a response signal from the RFID tag by the antenna, processes the response signal (received signal) received by the antenna, and supplies it to the processor 21. For example, the communication control circuit supplies the processor 21 with tag information included in the received signal from the RFID tag, and an RSSI value and a phase value indicating the strength of the received signal.

[0040] The interface 26 may be any interface that corresponds to the interface 33 included in the information terminal device 13. For example, the interface 26 may be an interface that physically contacts and connects to an interface included in the information terminal device 13, such as a Universal Serial Bus (USB) interface or a LAN interface. The interface 26 may also be an interface that wirelessly connects for communication, such as a Bluetooth (registered trademark) interface or a Wifi (registered trademark) interface.

[0041] The reader device 10 as the radio tag communication device 1 has a power source that supplies power for operation. In the handheld radio tag communication device 1, for example, a rechargeable battery (secondary battery) is provided as the power source. The battery supplies each part of the radio tag communication device 1 with power for operating the parts.

[0042] 3, the information terminal device 13 is set in a holder 12 of a reader device 10 serving as a wireless tag communication device 1. The information terminal device 13 may be any device that includes a display device 14, an input device 15, etc., and that is communicatively connected to the reader device 10 serving as a wireless tag communication device 1. The information terminal device 13 is, for example, a portable information processing device such as a smartphone or a tablet PC.

[0043] As shown in FIG. 3, the information terminal device 13 includes a processor 31, a memory 32, an interface (I / F) 33, a sensor 34, a camera 35, the display device 14, an input device 15, and the like. The processor 31 controls each unit, processes data, etc. The processor 31 is, for example, a CPU. The processor 31 executes programs stored in the memory 32 to realize various operations.

[0044] The interface 33 is an interface (second communication interface) for communication connection with the interface 26. The interface 33 may be any interface that is compatible with the interface 26. For example, the interface 33 is an interface such as a LAN, USB, Bluetooth, or Wifi.

[0045] The sensor (sensor group) 34 includes a sensor that detects the position or a change in position of the information terminal device 13. For example, the sensor 34 is an acceleration sensor, a gyro sensor, or a geomagnetic (direction) sensor. The sensor 34 may include a plurality of types of sensors. The sensor 34 may include a position detection sensor for detecting the position. In this case, the sensor 34 is an example of a position detection sensor that detects information indicating the self-position (position of the communicator). Note that some or all of the sensors as the sensor 34 described above may be provided in the reader device 10.

[0046] The camera 35 captures an image. The image capturing direction of the camera 35 changes according to the orientation of the reader device 10 when the information terminal device 13 is set in the reader device 10. For example, the image capturing direction of the camera 35 may be set to match the orientation of the antenna of the wireless tag communication unit 23 included in the reader device 10.

[0047] The image captured by the camera 35 is used to estimate the position (position of the device itself) of the information terminal device 13 (the wireless tag communication device 1 consisting of the reader device 10 in which the information terminal device 13 is set). The camera 35 is an example of a position detection sensor that detects information indicating its own position (position of the communicator). For example, the processor 31 of the information terminal device 13 identifies its own position based on the image captured by the camera 35 by a method of self-position estimation used in AR technology.

[0048] Next, the configuration of the RFID tag communication unit 23 in the RFID tag communication device 1 according to the embodiment will be described in detail. As described above, the wireless tag communication unit (communicator) 23 has a communication control circuit and an antenna. The communication control circuit of the wireless tag communication unit 23 has a modulation circuit, a transmitting amplifier circuit, a coupler, a receiving amplifier circuit, a demodulation circuit, an output setting circuit, and a level detection circuit. The antenna of the wireless tag communication unit 23 is connected to the coupler in the communication control circuit. The antenna transmits and receives radio waves for communication with the RFID tag. The communication control circuit processes signals to be transmitted to the RFID tag via the antenna and signals received from the RFID tag.

[0049] The modulation circuit modulates a waveform signal (carrier wave) with the input transmission data. The amplifier circuit on the transmitting side amplifies the output signal of the modulation circuit. The coupler supplies the output signal of the amplifier circuit on the transmitting side to the antenna. With this configuration, the communication control circuit outputs a carrier wave modulated with the transmission data from the antenna.

[0050] The RFID tag receives radio waves as a transmission signal transmitted from the antenna. The RFID tag recognizes, for example, a read command contained in the transmission signal transmitted from the antenna. When the RFID tag recognizes the read command, it outputs data (tag information) stored in its own memory by radio waves, for example by backscatter modulation.

[0051] The antenna receives radio waves as a reception signal output by the RFID tag. The communication control circuit acquires the reception signal received by the antenna using a coupler and supplies the acquired reception signal to the receiving amplifier circuit. The receiving amplifier circuit amplifies the reception signal received by the antenna. The demodulation circuit demodulates the data (tag information) contained in the reception signal amplified by the receiving amplifier circuit.

[0052] The antenna of the radio tag communication unit 23 has directionality and is installed at a predetermined position of the radio tag communication device 1 facing a predetermined direction. The antenna is, for example, a planar antenna. However, the antenna of the radio tag communication unit 23 is not limited to a specific configuration. The antenna is placed in the housing so as to transmit electromagnetic waves (output signals) toward a communication area (reading area) centered on the direction where the directivity is maximum (for example, direction a shown in FIG. 1). The radio tag communication device 1 is configured so that the direction where the antenna's directivity is maximum is the front (direction a shown in FIG. 1).

[0053] Furthermore, the communication control circuit of the RFID tag communication unit 23 sets the strength (output value) of the signal to be output by the output setting circuit. The transmitting amplifier circuit amplifies the signal supplied from the modulation circuit to the output value set by the output setting circuit. The antenna transmits an output signal (radio wave) of the output value set by the output setting circuit, which is supplied from the transmitting amplifier circuit via a coupler.

[0054] The wireless tag communication unit 23 sets a range (reading area) in which radio waves to which an RFID tag can respond are transmitted according to the direction of the antenna and the output value of the radio waves output from the antenna. The reading area by the wireless tag communication unit 23 is set according to the direction of the antenna, the directivity of the antenna, and the output value of the output signal. The wireless tag communication unit 23 sets the reading area by controlling the output value of the output signal according to instructions from the processor 21.

[0055] The communication control circuit of the wireless tag communication unit 23 processes the response signal (received signal) received by the antenna and supplies it to the processor 21. The communication control circuit supplies the processor 21 with tag information, an RSSI value indicating the strength of the received signal, and a phase value, contained in the received signal from the RFID tag. For example, the communication control circuit of the wireless tag communication unit 23 detects information for identifying the RSSI value indicating the strength of the received signal (response signal from the RFID tag) received by the antenna using a level detection circuit. The processor 21 also acquires phase values ​​of multiple received signals received by the communication control circuit of the wireless tag communication unit 23 at different positions of the device itself, and detects the phase difference between the received signals received at the different positions.

[0056] Next, a tag position estimation process for estimating the position of an RFID tag (hereinafter, referred to as a target tag) that is a search target of the wireless tag communication device 1 according to the embodiment will be described. The wireless tag communication device 1 reads the target tag while moving from position to position (own position) while being held by an operator. The wireless tag communication device 1 estimates (determines) the direction of the target tag at multiple positions, and estimates the position of the target tag based on the direction of the target tag from the multiple positions. The wireless tag communication device 1 obtains the read results of the target tag read at multiple positions (own position). The wireless tag communication device 1 estimates the direction of the target tag from each position based on the read result at each position and the read result at the next position. Furthermore, the wireless tag communication device 1 estimates the position of the target tag based on the direction of the target tag from the multiple positions.

[0057] FIG. 4 is a diagram showing an example of the positional relationship when the wireless tag communication device 1 reads the target tag O at three different positions. 4, it is assumed that the wireless tag communication device 1 reads the target tag O at a first position Pa, a second position Pb, and a third position Pc. For example, an operator holding the wireless tag communication device 1 reads the target tag O while moving in order among the first position Pa, the second position Pb, and the third position Pc.

[0058] The processor 21 of the wireless tag communication device 1 stores read information including the position of the device itself and the phase of the received signal as a result of reading the target tag at each position in the memory 22. The processor 21 determines the distance Lr between the first position Pa and the second position Pb from the read information at the first position Pa and the read information at the second position Pb. The processor 21 also determines the differential distance Li between the distance PaO from the first position Pa to the target tag O and the distance PbO from the second position Pb to the target tag O.

[0059] The differential distance Li is calculated from the difference (phase difference) between the phase of the received signal (response wave) received at the first position Pa and the phase of the signal (response wave) received at the second position Pb. In other words, the differential distance (Li=La-LB) between the distance La from the first position Pa to the target tag O and the distance Lb from the second position Pb to the target tag O appears as a phase difference (amount of phase change). Thus, the processor 21 determines the differential distance Li from the phase difference obtained from the read information at the first position Pa and the read information at the second position Pb.

[0060] The processor 21 derives (estimates) the angle D of the angle OAB from the ratio Li / Lr between the distance Lr and the difference distance Li. Here, the angle D derived (estimated) from the ratio Li / Lr is stored in advance as a judgment table in the memory 22. After calculating the ratio Li / Lr, the processor 21 judges the angle D corresponding to the calculated Li / Lr based on the judgment table.

[0061] 4, angle OPaPb is angle D formed by line segment PaPb and line segment PaO. Therefore, when the positions (position coordinates) of position Pa and position Pb are specified, the direction from position Pa to target tag O (a straight line passing through position Pa and target tag O) can be specified. Processor 21 determines the direction from position Pa to target tag O based on angle D of angle OAB determined from ratio Li / Lr.

[0062] Using a method similar to that described above, the processor 21 determines the distance Lr' between the second position Pb and the third position Pc from the read information at the second position Pb and the read information at the third position Pc. The processor 21 determines the differential distance Li' between the distance PbO from the second position Pb to the target tag O and the distance PcO from the third position Pc to the target tag O. The differential distance Li' is determined by the phase difference obtained from the read information at the second position Pc and the read information at the third position Pc.

[0063] The processor 21 calculates the ratio Li' / Lr' between the distance Lr' and the differential distance Li', and determines the angle D' corresponding to the calculated Li' / Lr' based on a determination table. The processor 21 determines the direction of the target tag O from the second position Pb (a straight line passing through the position Pb and the target tag O) based on the angle D' of the angle OPbPc determined from the ratio Li' / Lr'.

[0064] The processor 21 determines (estimates) the position of the target tag O based on the direction of the target tag from the first position Pa and the direction of the target tag from the second position Pb. For example, the processor 21 determines the intersection of a straight line PaO passing through the first position Pa and the target tag O and a straight line PbO passing through the second position Pb and the target tag O as the position of the target tag O.

[0065] That is, the RFID tag communication device 1 determines (estimates) the direction from one position to the target tag from the read information of the target tag at two positions. The RFID tag communication device 1 reads the target tag at three or more positions and determines the directions from the multiple positions to the target tag. The RFID tag communication device 1 determines the position of the target tag based on the directions from the multiple positions to the target tag.

[0066] Next, a determination table for the RFID tag communication device 1 to determine the direction of the target tag will be described. Fig. 5 is a diagram showing an example of a determination table stored in the memory 22 of the wireless tag communication device 1. Fig. 5 is a table showing the relationship between the angle D and the ratio Li / Lr of the distance Lr between two positions and the difference (distance difference) Li between the distances from the two positions to the target tag.

[0067] The decision table shown in Fig. 5 records each value in two-dimensional coordinates with the position of the search object (target tag) as the origin O (0, 0) and the coordinates of reference position A as (0, 8). (X, Y) in Fig. 5 indicates the coordinates of variable position B when the moving distance Lr from reference position A is 0.5 m. The angle in Fig. 5 is the angle (angle OAB) between the straight line connecting the target tag position O and reference position A and the straight line connecting reference position A and variable position B. The distance shown in Fig. 5 indicates the distance between variable position B and the target tag position O.

[0068] The differential distance Li in Fig. 5 is the distance (Li = La - Lb) obtained by subtracting the distance Lb between the target tag's position O and the variable position B from the distance La between the target tag's position O and the reference position A. The differential distance Li is a distance calculated from the amount of phase change between the phase of the signal received from the target tag at the reference position A and the phase of the signal received from the target tag at the variable position B. The ratio Li / Lr in Fig. 5 is the ratio between the moving distance Lr and the differential distance Li.

[0069] Fig. 6 is a graph showing the relationship between the angle specified based on the values ​​shown in Fig. 5 and the ratio Li / Lr. According to the table shown in Fig. 5 or the graph shown in Fig. 6, the angle of the angle OAB can be determined from the ratio Li / Lr. In other words, when the coordinates of position A and the coordinates of position B and the angle of the angle OAB are specified, the direction in which the target tag is located from position A can be determined even if the coordinates of the target tag are not known.

[0070] By using the table shown in Fig. 5 or the graph shown in Fig. 6, the angle D shown in Fig. 4 can be calculated from the movement distance Lr and the difference distance Li. Similarly, the angle D' shown in Fig. 4 can be calculated from the movement distance Lr' and the difference distance Li'. As a result, the position of the target tag shown in Fig. 4 can be determined based on the direction from position Pa to the target tag (angle D) and the direction of the target tag from the second position Pb (angle D').

[0071] Hereinafter, an example of a search process including a process in which the RFID tag communication device 1 according to the embodiment is unable to obtain a read result of the target tag while performing a tag position estimation process will be described. The wireless tag communication device 1 estimates the position of the target tag based on the read results of the target tag at three different locations by the above-mentioned tag position estimation process. The wireless tag communication device 1 estimates the position of the target tag at a predetermined interval based on the read results of reading the target tag at a predetermined read cycle. The predetermined interval is not limited to the read cycle, and may be a predetermined cycle (time) different from the read cycle, or may be a predetermined distance relative to the moving distance of the self-position.

[0072] In actual operation, the RFID tag communication unit 23 of the RFID tag communication device 1 may temporarily be unable to read the target tag. If there is a period during which the RFID tag communication device 1 is unable to read the target tag, it may not be able to obtain the read results of reading the target tag at a predetermined interval. To estimate the tag position at a predetermined interval by the above-mentioned tag position estimation process, it is necessary to obtain the read results of reading the target tag at a predetermined interval and identify the distance to the target tag.

[0073] The distance to the target tag is identified by the amount of phase change (phase difference) in the reading results of the target tag at different self-positions. Therefore, to estimate the position of the target tag at a predetermined interval, the reading results of reading the target tag at the predetermined interval are required. In other words, if the target tag cannot be read at the predetermined interval (if a phase value cannot be obtained), it becomes impossible to estimate the tag position at the predetermined interval. The wireless tag communication device 1 according to the embodiment provides a search process that includes a process of continuously reporting the tag position (estimated tag position result) even if there is a temporary period when the target tag cannot be read.

[0074] Next, the process of reading a target tag by the wireless tag communication device 1 will be described. FIG. 7 is a diagram showing a change in phase in the read result when the RFID tag communication unit 23 of the RFID tag communication device 1 continuously reads target tags. As shown in FIG. 7, when moving at a constant speed relative to the target tag, the phase of the read results from successively reading the target tag changes periodically in the range from 0 degrees to 180 degrees. For example, in the example shown in FIG. 7, the phase changes from 0 degrees to 180 degrees every λ / 4 (approximately 8 cm) of distance. The wireless tag communication unit 23 of the wireless tag communication device 1 actually reads the target tag at a predetermined read cycle. Therefore, the actual read results of the target tag are discrete data acquired at the predetermined read cycle. Also, if there is a period during which the target tag cannot be read temporarily, there will be no read results for that period.

[0075] Fig. 8 is a diagram showing an example of plotting the read results (phase) obtained by reading a target tag at a predetermined read cycle. Fig. 9 is a diagram showing an example of plotting the read results obtained by reading a target tag at a predetermined read cycle when there is a period T during which the target tag cannot be read. When actually searching for a target tag, the read result of the target tag will be discrete data for each predetermined read cycle in which the phase changes periodically in the range of 0 degrees to 180 degrees, as shown in Fig. 8. Furthermore, if the RFID tag communication device 1 is temporarily unable to read the target tag, a period T will appear in which there is no read result for the target tag, as shown in Fig. 9. In the above-mentioned tag position estimation process, the RFID tag communication device 1 will not be able to estimate the tag position during the period T in which no read result is obtained.

[0076] The radio tag communication device 1 according to the embodiment estimates the tag position based on a plurality of consecutive read results at a predetermined interval. Furthermore, the radio tag communication device 1 is capable of continuously reporting the tag position even if there is a period when the target tag cannot be read temporarily and the target tag cannot be read at a predetermined interval. In other words, the radio tag communication device 1 according to the embodiment can continuously report the highly accurate estimation result of the target tag even if there is a period when the target tag cannot be read.

[0077] Hereinafter, a first, second and third processing examples of the tag search processing by the wireless tag communication device 1 according to the embodiment will be described.

[0078] First, a first tag search process as a first processing example by the wireless tag communication device 1 according to the embodiment will be described. FIG. 10 is a flowchart for explaining an operation example of the first tag search process by the wireless tag communication device 1 according to the embodiment. The processor 21 of the wireless tag communication device 1 operates in a search mode after registering an operator who is a searcher based on information input by the input device 15. The processor 21 sets an RFID tag (target tag) to be searched for, as specified by the operator. After setting the target tag, the processor 21 starts a search process for the target tag in response to an instruction from the operator to start a search. When the processor 21 starts the search process for the target tag, it starts an estimation process for the position of the device itself (self-position) and a reading process for the target tag (ACT11, 12).

[0079] As a process of estimating the self-location, the processor 21 estimates the self-location based on a detection signal detected by a position detection sensor such as the sensor 24 or 34. The processor 21 may estimate a relative position from a processing start position as the self-location, or may estimate an absolute position. For example, as a process of estimating the self-location, the processor 21 repeatedly executes estimation of the self-location at a specific timing. The processor 21 may estimate the self-location at a reading cycle of a target tag described later. The processor 21 stores position information (self-location) as an estimation result of the self-location in the memory 22.

[0080] Furthermore, as a target tag reading process, the processor 21 performs a process of reading the target tag at a predetermined reading cycle by the wireless tag communication unit 23. The wireless tag communication unit 23 transmits a response request (read command) and receives, as a reception signal, a response wave output by an RFID tag in the reading area in response to the response request. The processor 21 determines whether or not the RFID tag (target tag) to be searched for has been read based on the tag information included in the reception signal.

[0081] When the processor 21 receives a signal from the target tag, it stores (records) the read result including phase information of the signal received from the target tag in the memory 22 as the read result of the target tag. The processor 21 stores the read result of the target tag in the memory 22 every time the processor 21 executes a read process at a predetermined read cycle. The processor 21 stores the read result of the target tag in the memory 22 in association with information indicating the timing of execution of the read process. For example, the processor 21 stores the read result of the target tag in the predetermined read cycle and position information as an estimation result of the self-position in association with each other in the memory 22. However, when the processor 21 is unable to read the target tag, the processor 21 may store the read result indicating that the target tag cannot be read and the estimation result of the self-position in association with each other in the memory 22.

[0082] The processor 21 acquires the read result of the target tag at every predetermined interval while executing the self-position estimation process and the tag reading process. The predetermined interval is an interval for acquiring three or more pieces of read information (phase information and self-position) for estimating the position of the target tag. The predetermined interval is an interval for estimating the tag position, and may be set to any information. For example, the predetermined interval may be a predetermined time (cycle) different from the read cycle for performing the target tag reading process, or may be a predetermined distance relative to the moving (changing) distance of the self-position.

[0083] The processor 21 judges whether the target tag has been read at the predetermined interval (ACT13). If the target tag has been read at the predetermined interval (ACT13, YES), the processor 21 records the read information in which the read result including the phase information of the signal from the target tag is associated with the position information indicating the target tag's own position in the memory 22 (ACT16). As a result, the read information at the predetermined interval is stored in the memory 22 as information for estimating the position of the target tag at the predetermined interval.

[0084] Furthermore, if the target tag has not been read within a predetermined interval (ACT13, NO), the processor 21 determines whether or not three or more pieces of read information are recorded in the memory 22 (ACT14). If three or more pieces of read information are not recorded in the memory 22 (ACT14, NO), the processor 21 returns to ACT13.

[0085] When three or more pieces of read information are recorded in the memory 22 (ACT14, Yes), the processor 21 calculates a phase value (phase information) to be complemented as a reading result of the target tag by the tag position (estimated tag position) estimated from the three pieces of read information recorded in the memory 22 and the self-position (ACT15). That is, the processor 21 calculates (estimates) the phase value of the signal assumed to be received from the target tag at the timing (the timing when the target tag could not actually be read) from the self-position and the estimated tag position. For example, the phase value of the received signal from the target tag varies as shown in FIG. 7. This allows the processor 21 to estimate (calculate) the phase value at the timing based on the self-position at the timing and the most recently estimated tag position.

[0086] When the processor 21 calculates the phase value when the target tag could not be read, the processor 21 complements the calculated phase value as the reading result of the target tag at that timing. The processor 21 records the reading result of the target tag complemented by the calculated phase value and the position information of the self-position as the reading information at that timing in the memory 22 (ACT16). This allows the processor 21 to record the reading information consisting of the complemented reading result and the self-position in the memory 22 even at the timing when the target tag could not be read.

[0087] When the processor 21 records (appends) the read information in the memory 22, it determines whether or not there are three or more pieces of read information at different positions including the read information recorded in the memory 22 (ACT17). If there are not three or more pieces of read information at different positions (ACT17, No), the processor 21 cannot perform tag position estimation processing for the target tag, and therefore returns to ACT13.

[0088] If there are three or more pieces of read information at different positions (ACT17, Yes), the processor 21 executes a tag position estimation process for the target tag using the three pieces of read information including the read information recorded in the memory 22 (ACT18). That is, the processor 21 selects the three most recent pieces of read information from the read information recorded in the memory 22 including the read information of the complemented read result of the target tag. The processor 21 estimates the position of the target tag by executing the tag position estimation process as described above using the three selected pieces of read information.

[0089] For example, it is assumed that the processor 21 selects the first, second, and third read information at a predetermined interval as the tag position estimation process. In this case, the processor 21 specifies the direction from the first position indicated by the first read information to the target tag and the direction from the second position indicated by the second read information to the target tag. The direction from the first position to the target tag is specified from the ratio of the distance Lr from the first position to the second position to the difference distance Li of the distance to the target tag, according to the relationship shown in FIG. 5 or FIG. 6. The direction from the second position to the target tag is specified from the ratio of the distance Lr' from the second position to the third position to the difference distance Li' of the distance to the target tag. When the processor 21 specifies the directions from the multiple positions to the target tag, it determines (estimates) the position of the target tag based on the coordinates of each position and the direction from each position to the target tag.

[0090] When the processor 21 estimates the position of the target tag, it notifies the estimated position of the target tag (ACT19). For example, the processor 21 displays information indicating the estimated position of the target tag on the display 14. This allows the operator to directly know the position where the target tag exists, rather than the direction in which the target tag is located.

[0091] Furthermore, processor 21 accepts an instruction to end the search after reporting the position of the target tag (ACT20). For example, processor 21 accepts an instruction to end the search given by an operator using input device 15. If there is no instruction to end the search (ACT20, NO), processor 21 returns to ACT13 and repeats the above-mentioned process. Furthermore, if an instruction to end the search is given (ACT20, YES), processor 21 ends the search process for the target tag.

[0092] As described above, according to the first search process, the RFID tag communication device checks whether the target tag has been read at predetermined intervals. If the target tag has been read, the RFID tag communication device records in memory the read result including the phase of the signal from the target tag and read information including its own position. If the target tag cannot be read, the RFID tag communication device calculates the phase value at that timing from its own position and the estimated tag position. The RFID tag communication device records information consisting of the calculated phase value and its own position in memory as read information at the timing when the target tag could not be read. The RFID tag communication device estimates the tag position using the three read information recorded in memory at predetermined intervals, and reports the tag position as the estimated result.

[0093] This allows the RFID tag communication device to obtain an estimate of the target tag's position at a predetermined interval even if there is a period during which the target tag cannot actually be read. As a result, the RFID tag communication device can update the target tag's position at a predetermined interval and continuously report the target tag's position with high accuracy.

[0094] Next, a second tag search process as a second processing example by the wireless tag communication device 1 according to the embodiment will be described. FIG. 11 is a flowchart for explaining an operation example of the second tag search process by the wireless tag communication device 1 according to the embodiment. The processor 21 of the wireless tag communication device 1 operates in a search mode after registering an operator who is a searcher based on information input by the input device 15. The processor 21 sets an RFID tag (target tag) to be searched for, as specified by the operator. After setting the target tag, the processor 21 starts a search process for the target tag in response to an instruction from the operator to start a search. When the processor 21 starts the search process for the target tag, it starts an estimation process for the position of the device itself (self-position) and a reading process for the target tag (ACT31, 32).

[0095] As a process of estimating the self-location, the processor 21 estimates the self-location based on a detection signal detected by the sensor 24 or 34. The processor 21 may estimate a relative position from a processing start position as the self-location, or may estimate an absolute position. As a process of estimating the self-location, the processor 21 repeatedly executes estimation of the self-location at a specific timing. For example, the processor 21 may estimate the self-location at a reading cycle of a target tag described later. The processor 21 stores position information as an estimation result of the self-location in the memory 22. Furthermore, as a process for reading a target tag, the processor 21 executes a read process for reading the target tag at a predetermined read cycle by the wireless tag communication unit 23. The wireless tag communication unit 23 transmits a response request (read command) and receives, as a received signal, a response wave outputted by an RFID tag in the read area in response to the response request. The processor 21 determines whether or not the RFID tag (target tag) to be searched for has been read based on the tag information included in the received signal.

[0096] When the processor 21 receives a signal from the target tag, it stores (records) the read result including phase information of the signal received from the target tag in the memory 22 as the read result of the target tag. The processor 21 stores the read result of the target tag in the memory 22 every time the processor 21 executes a read process at a predetermined read cycle. The processor 21 stores the read result of the target tag in the memory 22 in association with information indicating the timing of execution of the read process. For example, the processor 21 stores the read result of the target tag in the predetermined read cycle and position information as an estimation result of the self-position in association with each other in the memory 22. However, when the processor 21 is unable to read the target tag, the processor 21 may store the read result indicating that the target tag cannot be read and the estimation result of the self-position in association with each other in the memory 22.

[0097] The processor 21 acquires the reading result of the target tag at a predetermined interval (a predetermined period or a predetermined distance) while executing the self-location estimation process and the tag reading process. The processor 21 judges whether the target tag has been read at the predetermined interval (ACT33). If the target tag has not been read at the predetermined interval (ACT33, NO), the processor 21 returns to the above ACT33.

[0098] When the target tag is read (ACT33, YES), the processor 21 records the read information in which the read result of the target tag including the phase information of the signal from the target tag is associated with the position information indicating the target tag's own position in the memory 22 (ACT34). As a result, the read information at the predetermined intervals is accumulated in the memory 22 as information for estimating the position of the target tag at the predetermined intervals.

[0099] When the processor 21 records the read information in the memory 22, it determines whether or not three or more pieces of read information at different positions are recorded in the memory 22 (ACT35). If three or more pieces of read information at different positions are not recorded in the memory 22 (ACT35, NO), the processor 21 returns to ACT33.

[0100] When three or more pieces of read information at different positions are recorded in memory 22 (ACT35, Yes), processor 21 judges whether or not the most recent three pieces of read information including the read information recorded in memory 22 are consecutive at a predetermined interval (ACT36). That is, processor 21 judges whether or not three consecutive pieces of read information at different positions at a predetermined interval including the latest read information are recorded in memory 22.

[0101] If the most recent three pieces of read information are not consecutive at a predetermined interval (ACT36, No), processor 21 does not estimate the tag position and proceeds to ACT38. In other words, if the most recent three pieces of read information are not consecutive at a predetermined interval, processor 21 continues to notify the currently notified (displayed) tag position. For example, if the most recent three pieces of read information are not consecutive at a predetermined interval, processor 21 continues to display the tag position without updating the tag position displayed on display 14.

[0102] If the most recent three pieces of read information are consecutive at a predetermined interval (ACT36, Yes), the processor 21 estimates the position of the target tag using the three pieces of read information consecutive at a predetermined interval (ACT37). The processor 21 estimates the position of the target tag by the above-mentioned tag position estimation process. When the processor 21 estimates the position of the target tag, it notifies the estimated position of the target tag (ACT38). For example, the processor 21 stores the tag position estimation result in the memory 22, and updates the position of the target tag displayed on the display 14 to the position of the target tag estimated by the latest tag position estimation process. This allows the processor 21 to notify the estimated position of the target tag when three pieces of read information consecutive at a predetermined interval are obtained.

[0103] Furthermore, the processor 21 receives an instruction to end the search while reporting the position of the target tag (ACT39). If there is no instruction to end the search (ACT39, NO), the processor 21 returns to ACT33 and repeats the above-mentioned process. Furthermore, if an instruction to end the search is received (ACT39, YES), the processor 21 ends the search process for the target tag.

[0104] As described above, according to the second search process, the RFID tag communication device records read information including the read result of the target tag and its own position in memory when the target tag is read at a predetermined interval. When three consecutive read information are recorded in memory at a predetermined interval, the RFID tag communication device estimates the tag position and notifies the tag position as the estimated result.

[0105] This allows the RFID tag communication device to update the tag position to be reported only when consecutive read information is obtained at a predetermined interval, and as a result, the RFID tag communication device can report the target tag position with high accuracy obtained by consecutive read information at a predetermined interval.

[0106] Next, a third tag search process as a third processing example by the wireless tag communication device 1 according to the embodiment will be described. FIG. 12 is a flowchart for explaining an operation example of the third tag search process by the wireless tag communication device 1 according to the embodiment. The processor 21 of the wireless tag communication device 1 operates in a search mode after registering an operator who is a searcher based on information input by the input device 15. The processor 21 sets an RFID tag (target tag) to be searched for, as specified by the operator. After setting the target tag, the processor 21 starts a search process for the target tag in response to an instruction from the operator to start a search. When the processor 21 starts the search process for the target tag, it starts an estimation process for the position of the device itself (self-position) and a reading process for the target tag (ACT51, 52).

[0107] The processor 21 repeatedly executes estimation of the self-location based on a detection signal detected by the sensor 24 or 34 at a specific timing, similar to ACT 11 or 31 described above. The processor 21 stores position information as an estimation result of the self-location in the memory 22. For example, the processor 21 stores the position information in the memory 22 in association with information indicating the timing at which the self-location is estimated.

[0108] Similarly to ACT 12 or 32, the processor 21 executes a read process to read the target tag at a predetermined read cycle by the wireless tag communication unit 23. The processor 21 stores the result of reading the target tag at the predetermined read cycle in the memory 22. Here, the processor 21 stores the result of reading the target tag at the predetermined read cycle in the memory 22 in association with the position information (self-position) as an estimation result of the self-position.

[0109] The processor 21 acquires the target tag reading result at a predetermined interval (predetermined period or predetermined distance) while executing the self-location estimation process and the tag reading process. The processor 21 determines whether the target tag has been read based on the target tag reading result acquired at the predetermined interval (ACT53). If the target tag has been read (ACT53, YES), the processor 21 proceeds to ACT57.

[0110] In ACT57, the processor 21 records the read information in which the read result of the target tag, including the phase value (phase information) of the signal from the target tag, corresponds to the position information indicating the target tag's own position in the memory 22 (ACT57). As a result, the read information at the predetermined intervals is accumulated in the memory 22 as information for estimating the position of the target tag at the predetermined intervals.

[0111] Furthermore, if the target tag is not read at a predetermined interval (ACT53, NO), the processor 21 determines whether or not to execute a data (read information) complementation process (ACT54). Here, it is assumed that whether or not to complement the read information with a phase value estimated as a read result at the timing when the target tag cannot be read is set in advance. For example, the processor 21 sets whether or not to execute complementation of the read information according to an instruction set by the operator.

[0112] If the read information is not complemented, the processor 21 determines that there is no read information at that timing and returns to ACT53. When complementing the read information (ACT54, Yes), the processor 21 judges whether or not three or more pieces of read information at different positions are recorded in the memory 22 (ACT55). If three or more pieces of read information at different positions are not recorded in the memory 22 (ACT55, NO), the processor 21 returns to ACT53.

[0113] When three or more pieces of read information at different positions are recorded in the memory 22 (ACT55, Yes), the processor 21 calculates a phase value (phase information) at the timing from the self-position and the estimated tag position (ACT56). For example, the processor 21 calculates (estimates) a phase value assumed as the phase of a received signal from a target tag from the self-position at the timing and the estimated tag position. As a specific example, the processor 21 assumes a phase fluctuation as shown in Fig. 7 and calculates a phase value at the timing from the self-position at the timing and the most recent estimated tag position.

[0114] When the processor 21 calculates the phase value as the complementary data, the processor 21 generates the read result of the calculated phase value and the self-position as read information at the timing. The processor 21 records the read information generated by the phase value calculated as the complementary data in the memory 22 as the read information at the timing (ACT57). This allows the processor 21 to record the read information consisting of the read result of the complementary phase value and the self-position (position information) in the memory 22 even at a timing when the target tag cannot be read.

[0115] Furthermore, when the processor 21 records (appends) the read information in the memory 22, it determines whether or not there are three or more pieces of read information at different positions recorded in the memory 22 (ACT58). If there are not three or more pieces of read information at different positions (ACT58, No), the processor 21 cannot perform tag position estimation processing for the target tag, and therefore returns to ACT53.

[0116] If there are three or more pieces of read information at different positions (ACT58, Yes), the processor 21 judges whether or not the three most recent pieces of read information at different positions are consecutive at a predetermined interval (ACT59). That is, the processor 21 judges whether or not the three pieces of read information at different positions including the most recent read information recorded in the memory 22 are consecutive at a predetermined interval.

[0117] If the most recent three pieces of read information are not consecutive at a predetermined interval (ACT59, No), the processor 21 does not estimate the tag position and proceeds to ACT61. In other words, if the most recent three pieces of read information are not consecutive at a predetermined interval, the processor 21 continues to notify the current tag position. For example, if the most recent three pieces of read information are not consecutive at a predetermined interval, the processor 21 continues to display the tag position without updating the tag position displayed on the display 14.

[0118] When the most recent three pieces of read information are consecutive at a predetermined interval (ACT59, Yes), the processor 21 estimates the position of the target tag using the most recent three pieces of read information consecutive at a predetermined interval (ACT60). That is, the processor 21 estimates the position of the target tag by the above-mentioned tag position estimation process using the most recent three pieces of read information. When the processor 21 estimates the position of the target tag, it notifies the estimated position of the target tag (ACT61). For example, the processor 21 updates the position of the target tag displayed on the display 14 to the position of the target tag estimated by the tag position estimation process. This allows the processor 21 to notify the position of the target tag to be updated to a position estimated using the most recent three pieces of read information consecutive at a predetermined interval.

[0119] Furthermore, the processor 21 receives an instruction to end the search while reporting the position of the target tag (ACT62). If there is no instruction to end the search (ACT62, NO), the processor 21 returns to ACT53 and repeats the above-mentioned process. Furthermore, if an instruction to end the search is received (ACT62, YES), the processor 21 ends the search process for the target tag.

[0120] As described above, according to the third search process, the RFID tag communication device records read information including the read result of the target tag and its own position in memory when the target tag is read at a predetermined interval. Also, when the RFID tag communication device cannot read the target tag at a predetermined interval, it records read information supplemented with a phase value calculated from its own position and the estimated tag position in memory. When three consecutive read information pieces are recorded at a predetermined interval in memory, the RFID tag communication device estimates the tag position and reports the tag position as the estimation result.

[0121] This allows the RFID tag communication device to supplement the read information when the target tag cannot be read at a predetermined interval, and ensures read information at each predetermined interval. Furthermore, the RFID tag communication device can update the tag position to be reported only when consecutive read information is obtained at a predetermined interval. As a result, the RFID tag communication device can report the target tag position with high accuracy obtained from consecutive read information at a predetermined interval.

[0122] In the above-mentioned embodiment, the case where the program executed by the processor is stored in advance in the memory in the device has been described. However, the program executed by the processor may be downloaded to the device from a network, or may be installed in the device from a storage medium. The storage medium may be any storage medium capable of storing a program such as a CD-ROM and readable by the device. Furthermore, the function obtained by pre-installation or downloading may be realized in cooperation with an OS (operating system) in the device.

[0123] Although some embodiments of the present invention have been described, these embodiments are presented as examples and are not intended to limit the scope of the invention. These novel embodiments can be implemented in various other forms, and various omissions, substitutions, and modifications can be made without departing from the spirit of the invention. These embodiments and their modifications are included in the scope and spirit of the invention, and are included in the scope of the invention and its equivalents described in the claims. [Explanation of symbols]

[0124] 1...wireless tag communication device, 10...reader device, 11...gripping portion, 12...holding portion, 13...information terminal device, 14...display, 15...input device, 21...processor 21...memory, 23...wireless tag communication portion (communication device), 24...sensor (position detection sensor), 25...communication interface (interface), 26...camera (position detection sensor), 31...processor, 32...memory, 33...interface, 34...sensor (position detection sensor), 35...camera (position detection sensor).

Claims

1. A communication device for communicating with a target wireless tag; A position detection sensor that detects information indicating the self-position; a memory that stores a self-location determined from detection information of the position detection sensor and a reading result obtained by reading the wireless tag by the communication device in association with each other; a processor for estimating a position of the wireless tag when three or more consecutive read results of the wireless tag are obtained at a predetermined interval stored in the memory; A wireless tag communication device having the above configuration.

2. Further, the device has a display for displaying information, the processor displays, on the display, information indicating the estimated position of the wireless tag when three or more wireless tag read results are obtained consecutively within the predetermined interval. The wireless tag communication device according to claim 1 .

3. The processor estimates the position of the wireless tag when three or more consecutive read results of the wireless tag are obtained within a predetermined period that is the predetermined interval. The wireless tag communication device according to claim 1 .

4. the processor estimates the position of the wireless tag when a change in the self-position determined from the detection information of the position detection sensor indicates that three or more consecutive read results of the wireless tag are obtained within a predetermined distance, which is the predetermined interval; The wireless tag communication device according to claim 1 .

5. the processor further complements the wireless tag reading result based on the self-position identified from the detection information of the position detection sensor and the estimated position of the wireless tag when the wireless tag reading result cannot be obtained within the predetermined interval. The wireless tag communication device according to claim 1 .

6. In the information processing device, Obtaining the result of reading the target wireless tag by the communication device; acquiring location information indicating a location of the communication device; The wireless tag is read by the communication device, and the read result is associated with the location information and stored in a memory; when three or more consecutive read results of the wireless tags are obtained at a predetermined interval stored in the memory, the position of the wireless tag is estimated; A program to make it happen.

Images