Information processing device, information processing system, information processing method, and program

Abstract

To estimate the position of a passive tag.SOLUTION: When there is a passive tag, an information processing device obtains information about received signal strength at a transmitter / receiver of a reflected wave transmitted in response to a radiation wave transmitted from the transmitter / receiver, obtains information about the received signal strength and angle of arrival of the radiation wave received by a reference receiver, obtains the position of the reference receiver, estimates the position of the transmitter / receiver on the basis of the obtained position of the reference receiver and the obtained information about the received signal strength and angle of arrival of the radiation wave, and estimates the position of the passive tag on the basis of the estimated position of the transmitter / receiver and the obtained information about the received signal strength of the reflected wave.SELECTED DRAWING: Figure 15

Description

[Technical field]

[0001] The present invention relates to an information processing device, an information processing system, an information processing method, and a program for estimating the position of a passive tag. [Background technology]

[0002] 2. Description of the Related Art In logistics, inventory management, and the like, systems that use passive tags called RFID (Radio Frequency IDentification) tags to manage objects are widely used.

[0003] Passive tags receive radio waves (electromagnetic waves) emitted from an RFID reader and operate using the power generated by the received radio waves, so they have the advantage of not requiring a battery and can be manufactured thinly and inexpensively.

[0004] Considering the convenience of managing and searching for items, it is desirable to not only detect the presence or absence of a passive tag, but also to enable a manager to obtain the position information of the passive tag. Patent Document 1 describes a technology for estimating the position of a passive tag. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] JP 2018-159635 A Summary of the Invention [Problem to be solved by the invention]

[0006] The estimation of location information of a passive tag described in Patent Document 1 uses multiple receiving antennas to estimate the location of the passive tag based on the signal strength and signal phase difference of the reflected waves from the passive tag that arrive at the multiple receiving antennas. However, the accuracy of location estimation may decrease depending on the positions of the receiving antennas, transmitting antennas, and passive tag.

[0007] An object of the present invention is to provide a technique for estimating the position of a passive tag. [Means for solving the problem]

[0008] To achieve the above object, the information processing device according to the present invention comprises: a first acquiring means for acquiring information on a received signal strength at a transceiver of a reflected wave transmitted in response to a radiated wave transmitted from the transceiver when a passive tag is present; A second acquisition means for acquiring information regarding a received signal strength and an arrival angle of the radiation wave received by a reference receiver; a third acquisition means for acquiring a position of the reference receiver; a first estimation means for estimating a position of the transceiver based on the position of the reference receiver acquired by the third acquisition means and information regarding the received signal strength and the arrival angle of the radiated wave acquired by the second acquisition means; a second estimation means for estimating a position of the passive tag based on the position of the transceiver estimated by the first estimation means and information on the received signal strength of the reflected wave acquired by the first acquisition means; The present invention is characterized by comprising: Effect of the Invention

[0009] According to the present invention, it is possible to provide a technique for estimating the position of a passive tag. [Brief description of the drawings]

[0010] [Figure 1] FIG. 1 is a configuration diagram of a wireless communication system according to a first embodiment. [Diagram 2] A sequence diagram showing an example of a process executed by a wireless communication system. [Diagram 3] A diagram showing an example of the relative positions of an RFID reader, an RFID tag, and a reference RFID reader. [Figure 4] RFID reader block diagram [Diagram 5]Flowchart showing an example of processing executed by an RFID reader [Figure 6] Reference RFID Reader Block Diagram [Figure 7] 1 is a flowchart showing an example of a process executed by a reference RFID reader. [Figure 8] 1 is a flowchart showing a position estimation process executed by a host controller. [Figure 9] Host Controller Block Diagram [Figure 10] A diagram showing the method for estimating the position of an RFID tag based on the reflected wave reception results of a reference RFID reader and the estimation results. [Figure 11] A diagram showing how to estimate the transmission strength of an RFID tag [Figure 12] A table showing an example of a correspondence relationship between received signal strength and distance [Figure 13] A table showing an example of the correspondence relationship between the transmission strength of an RFID tag and the offset value of the received signal strength [Figure 14] A diagram showing the change in estimated position due to the change in the angle of arrival. [Figure 15] A diagram showing the method and results of estimating the position of an RFID tag based on the results of receiving emitted waves by a reference RFID reader and the results of receiving reflected waves by an RFID reader. [Figure 16] FIG. 1 is a configuration diagram of a wireless communication system according to a second embodiment. [Figure 17] FIG. 13 is a diagram showing a method for estimating the position of an RFID tag according to a third embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0011] First Embodiment Hereinafter, the embodiments will be described in detail with reference to the attached drawings. Note that the following embodiments do not limit the invention according to the claims. Although the embodiments describe a number of features, not all of these features are essential to the invention, and the features may be combined in any manner. Furthermore, in the attached drawings, the same reference numbers are used for the same or similar configurations, and duplicated descriptions are omitted.

[0012] Fig. 1 is a block diagram showing an example of a wireless communication system according to the present embodiment, Fig. 2 is a sequence diagram showing an operation executed by the wireless communication system shown in Fig. 1.

[0013] The wireless communication system 1 is an example of an information processing system including one or more RFID (Radio Frequency IDentification) readers 100, a reference RFID reader 102, and a host controller 103. When an RFID tag 101 is present within a transmission range and a reception range provided by the RFID reader 100 and the reference RFID reader 102, the wireless communication system 1 estimates the position of the RFID tag 101.

[0014] The RFID reader 100 is an example of a transceiver that can transmit electromagnetic waves in the UHF band to power the RFID tag 101 (S201) and detect the electromagnetic waves transmitted from the RFID tag 101 that receives the electromagnetic waves from the RFID reader 100 (S210). In this embodiment, the electromagnetic waves transmitted by the RFID reader 100 are called radiated waves, and the electromagnetic waves transmitted by the RFID tag 101 are called reflected waves. In one example, the radiated waves are encoded and modulated with data including identification information of the RFID reader 100 that transmits the radiated waves. In addition, the RFID reader 100 transmits a reception result of the reflected waves, including information regarding the reception signal strength of the reflected waves received by the RFID reader 100, to the host controller 103 (S211). In one example, the RFID reader 100 may transmit to the host controller 103 identification information of the other RFID reader 100 that sent out the reflected wave and information indicating the received signal strength based on the reception result of the emitted wave received by the RFID reader 100.

[0015] The RFID tag 101 is an example of a passive tag that can receive a radiation wave sent from the RFID reader 100 (S202) and send a reflected wave based on the power of the radiation wave (S206). In the RFID tag 101 of this embodiment, the reflected wave may be encoded and modulated with data including the identification information of the RFID tag 101. In addition, when the radiation wave is encoded and modulated with data including the identification information of the RFID reader 100, the reflected wave may be encoded and modulated with data including the identification information of the RFID reader 100 detected by the RFID tag 101. In addition, the RFID tag 101 of this embodiment has an anti-collision function that controls the timing of sending the reflected wave, and sends the reflected wave while avoiding collisions even when multiple RFID tags 101 are present. The timing of sending the reflected wave may be a timing specified by the RFID reader 100, or a timing delayed by a time corresponding to the identification information of the RFID tag 101, or a timing delayed by a predetermined time based on other variables.

[0016] The reference RFID reader 102 is an example of a reference receiver that has multiple antennas and can detect the signal strength and phase of the received electromagnetic waves. The reference RFID reader 102 has three or more, for example, four or more antennas, and each antenna can individually detect the signal strength and phase of the electromagnetic waves received by the antenna. In addition, the reference RFID reader 102 can estimate the relative angle (arrival angle) of the source of the electromagnetic waves with respect to the reference RFID reader 102 by comparing the phases of the electromagnetic waves received by the multiple antennas.

[0017] Therefore, the reference RFID reader 102 can detect the radiated wave transmitted from the RFID reader 100 and estimate the signal strength and the arrival angle of the radiated wave (S203). Also, the reference RFID reader 102 can detect the reflected wave transmitted from the RFID tag 101 and estimate the signal strength and the arrival angle of the reflected wave (S207).

[0018] The reference RFID reader 102 receives and decodes the radiated wave or the reflected wave, thereby obtaining the identification information of the RFID reader 100 or the RFID tag 101 that sent out the radiated wave or the reflected wave (S203, S207). The reference RFID reader 102 transmits the received signal strength and the arrival angle of the detected RFID reader 100 or RFID tag 101 to the host controller 103 (S204, S208). The reference RFID reader 102 may also transmit the identification information of the detected RFID reader 100 or RFID tag 101 to the host controller 103 (S204, S208).

[0019] The host controller 103 is an example of an information processing device that estimates the position of the RFID tag 101 based on the reception results of the reference RFID reader 102 and the RFID reader 100. The host controller 103 acquires and stores the distance to the source of the radiated wave or reflected wave and the angle of arrival estimated by the reference RFID reader 102, as well as the identification information of the source of the radiated wave or reflected wave (S205, S209). The host controller 103 can also estimate the position of the source of the radiated wave or reflected wave received by the reference RFID reader 102 from the reference information, the distance to the source of the radiated wave or reflected wave, and the angle of arrival (S205, S209). The host controller 103 has information (reference information) on the position and attitude of the reference RFID reader 102. The host controller 103 can also acquire the distance to the source of the radiated wave or reflected wave and the identification information of the source from the RFID reader 100 (S212). The host controller 103 executes a position estimation method described later, and can estimate the position of the source of the emitted wave or reflected wave received by the reference RFID reader 102 or the RFID reader 100. In addition, the host controller 103 outputs information related to the estimated position of the RFID tag 101 to the output unit 105 or an external device.

[0020] The communication between the reference RFID reader 102 and the host controller 103 is performed via wired or wireless (Bluetooth (registered trademark), wireless LAN) communication. The communication between the RFID reader 100 and the host controller 103 is performed via wireless (Bluetooth (registered trademark), wireless LAN) communication. In one example, the communication between the reference RFID reader 102, the host controller 103, and the RFID reader 100 may be performed via an access point (AP) 104.

[0021] FIG. 3 is a diagram showing an example of the relative positions of the RFID reader 100, the RFID tag 101, and the reference RFID reader 102. In one example, the RFID reader 100 is a portable mobile terminal. For this reason, the RFID reader 100 according to this embodiment is assumed to be carried around by a person, and an antenna that affects the size of the device is built into the device. For this reason, in this embodiment, the RFID reader 100 is described as having one antenna, but the number of antennas that the RFID reader 100 has is not limited to this. A case in which the RFID reader 100 has multiple antennas will be described later in the third embodiment. The RFID reader 100 can transmit UHF band high frequency power to the RFID tag 101 from any position above the floor surface.

[0022] As shown in FIG. 3, the reference RFID reader 102 is placed on a ceiling or the like to reduce the influence of obstacles. Since the reference RFID reader 102 according to this embodiment is fixed in position, portability is not required, and the size of the device can be freely determined. Therefore, the antenna provided in the reference RFID reader 102 does not need to be an antenna built into the device. For example, the reference RFID reader 102 can be a rod antenna or the like whose antenna element protrudes from the device. In this embodiment, the maximum gain of the antenna of the reference RFID reader 102 is higher than the maximum gain of the antenna of the RFID reader 100. Alternatively, the receiving circuit 122 may use an amplifier with a higher gain than the receiving circuit 113.

[0023] 4 shows a circuit block diagram of the RFID reader 100 in this embodiment. The RFID reader 100 is controlled by a control unit 110 that includes one or more processors such as a CPU (Central Processing Unit) and a memory.

[0024] Control unit 110 controls RF control unit 111 to transmit high frequency waves (radio waves) in the UHF band from antenna 114 via transmission circuit 112. The transmission power of the radio waves output from transmission circuit 112 is controlled by instructions from RF control unit 111. Control unit 110 may also control the transmission power output from transmission circuit 112 based on the control of RF control unit 111. For example, control unit 110 may instruct RF control unit 111 to increase or decrease the transmission power, or may instruct an output level corresponding to a target transmission power.

[0025] The radio waves radiated from the antenna 114 are received by the RFID tag 101, and the received power is used by the RFID tag 101 to radiate a reflected wave. That is, the RFID reader 100 supplies power to the RFID tag 101 by radiating a radio wave from the antenna 114. The RFID tag 101 uses the supplied power to communicate with the RFID reader 100 or the reference RFID reader 102 by transmitting a reflected wave.

[0026] The reflected wave from the RFID tag 101 received by the antenna 114 is demodulated and decoded in the receiving circuit 113, and the RF control unit 111 can obtain the identification information (ID information) of the RFID tag 101 and information on the received signal strength based on the reception result of the reflected wave. The receiving circuit 113 is a radio frequency (RF) circuit that receives the reflected wave and performs demodulation and decoding. The ID information of the RFID tag 101 that transmitted the reflected wave and information on the received signal strength are stored in the storage unit 115, and the control unit 110 transmits the identification information of the RFID tag 101 and information on the received signal strength to the host controller 103 via the external communication unit 116.

[0027] Fig. 5 is a flowchart showing an example of the operation of the RFID reader 100. The process shown in Fig. 5 is realized by the processor of the control unit 110 of the RFID reader 100 working together with the memory to execute a program when a positioning instruction is received from the host controller 103 or the reference RFID reader 102.

[0028] In S501, the RFID reader 100 executes carrier sense and determines whether or not a signal of a predetermined intensity or more is detected in a frequency band including the frequency band for transmitting the radiated wave in S502, that is, whether or not the channel is occupied. If the RFID reader 100 detects a signal of a predetermined intensity or more, it determines that the channel is not available (No in S501) and proceeds to processing at S507. On the other hand, if the RFID reader 100 does not detect a signal of a predetermined intensity or more and determines that the channel is available (Yes in S501), the RFID reader 100 proceeds to processing at S502 and transmits a radiated wave. In S502, the RFID reader 100 controls the RF control unit 111 to switch to the transmission circuit 112 and transmit the radiated wave from the antenna 114. As described above, the radiated wave transmitted in S502 may carry data including the identification information of the RFID reader 100.

[0029] In S503, the RFID reader 100 stops transmitting the radiated wave, and the RF control unit 111 controls the receiving circuit 113 to wait for the reflected wave from the RFID tag 101. If the reflected wave from the RFID tag 101 is detected within a predetermined time after transmitting the radiated wave (Yes in S504), the RFID reader 100 proceeds to process S505 and detects the identification information and received signal strength of the RFID tag 101 from the demodulated and decoded results of the reflected wave. If the reflected wave from the RFID tag 101 is not detected within a predetermined time after transmitting the radiated wave (No in S504), the RFID reader 100 proceeds to process S506 and notifies the host controller 103 that the reflected wave was not detected. In one example, if the RFID reader 100 does not detect a reflected wave from the RFID tag 101 within a predetermined time after transmitting the radiated wave (No in S504), the RFID reader 100 may not notify the host controller 103 and may end the process shown in Fig. 5. In this case, if the host controller 103 does not receive a notification of the measurement result from the RFID reader 100, it can determine that the RFID reader 100 did not receive a reflected wave.

[0030] In S505, the RFID reader 100 transmits a reception result of the reflected wave to the host controller 103. The reception result includes the identification information of the RFID tag 101 based on the detected reflected wave and the received signal strength of the reflected wave. The RFID reader 100 may also transmit its own identification information together with the reception result. After transmitting the reception result including the identification information of the RFID tag 101 and the received signal strength of the reflected wave to the host controller 103 in S506, the RFID reader 100 ends the process shown in FIG. 5.

[0031] As described above, by the process of FIG. 5, the host controller 103 can acquire, from the RFID reader 100 that has detected the reflected wave from the RFID tag 101, the identification information of the detected RFID tag 101 and information regarding the received signal strength (S211).

[0032] Fig. 6 is a block diagram showing the configuration of the reference RFID reader 102 according to this embodiment. Note that, although the reference RFID reader 102 is shown as having four antennas in the example of Fig. 6, the number of antennas may be any number as long as it is plural, and is not limited to four.

[0033] The reference RFID reader 102 includes a control unit 120, an RF control unit 121, receiving circuits 122a-d, antennas 123a-d, a storage unit 124, and an external communication unit 125. Hereinafter, the receiving circuits 122a-d may be referred to simply as receiving circuits 122, and the antennas 123a-d may be referred to simply as antennas 123.

[0034] The control unit 120 includes one or more processors such as a CPU and a memory, and executes a program stored in the memory to control the operation of the entire reference RFID reader 102. The RF control unit 121 decodes signals received by each receiving circuit 122, and transmits the decoded signals to the control unit 120. In one example, the RF control unit 121 controls the operation of the receiving circuit 122, including adjusting the frequency and gain for the receiving circuit 122 to demodulate the signal.

[0035] The receiving circuit 122 detects and demodulates the radiated wave transmitted from the RFID reader 100 and the reflected wave transmitted from the RFID tag 101, which are received via the antenna 123. In the example of Fig. 6, one receiving circuit is connected to one antenna, but one receiving circuit may be connected to four antennas. For example, the receiving circuit 122 may include a radio circuit for each antenna 123 that amplifies and modulates the electromagnetic wave received by the antenna 123, and the output from each radio circuit may be input to an analog-to-digital converter (ADC) having multiple input ports.

[0036] The RF control unit 121 decodes the signal demodulated by the receiving circuit 122 and detects the received signal strength and phase of each of the radiated wave sent from the RFID reader 100 and the reflected wave sent from the RFID tag 101. The RF control unit 121 transmits information about the detected received signal strength and phase to the control unit 120. In one example, the RF control unit 121 may transmit the received signal strength and phase of the signal to the control unit 120 in association with identification information of the receiving circuit 122 that demodulated the signal.

[0037] The control unit 120 receives information from the RF control unit 121 regarding the received signal strength and phase of the electromagnetic waves demodulated by each receiving circuit 122, and estimates the received signal strength and arrival angle of the radiated waves and reflected waves sent from the RFID reader 100 or RFID tag 101.

[0038] The control unit 120 stores the identification information of the RFID reader 100, the information on the received signal strength and the arrival angle received from the RF control unit 121 in the storage unit 124. Then, the control unit 120 transmits the identification information of the RFID reader 100, the information on the received signal strength and the arrival angle as reception results to the host controller 103 via the external communication unit 125. Similarly, the control unit 120 stores the identification information of the RFID tag 101, the information on the received signal strength and the arrival angle in the storage unit 124 based on the demodulation result of the reflected wave received from the RF control unit 121. Then, the control unit 120 transmits the identification information of the RFID tag 101, the information on the received signal strength and the arrival angle as reception results via the external communication unit 125.

[0039] The storage unit 124 is a storage device that stores various data including the identification information of the RFID tag 101 and the RFID reader 100 detected by the control unit 120, the received signal strength, and information regarding the arrival angle.

[0040] The external communication unit 125 communicates with the host controller 103 via any communication such as a wired or wireless local area network (LAN) or Bluetooth (registered trademark).

[0041] Similarly, the reflected wave from the RFID tag received by antenna 123 is demodulated by RF control unit 121 through receiving circuit 122, and the arrival angle is estimated from the RFID tag's ID information, signal strength, and phase difference of the arriving wave. The RFID tag's ID information and signal strength information are stored in memory unit 124, and external communication unit 125 is controlled by control unit 120, and the information is transmitted to host controller 103 via communication.

[0042] Fig. 7 is a flowchart showing an example of processing executed by the reference RFID reader 102. The processing shown in Fig. 7 is realized by the processor of the control unit 120 of the reference RFID reader 102 executing a program stored in the memory when an instruction to execute processing for estimating the position of the RFID tag 101 is received from the host controller 103.

[0043] In S701, the reference RFID reader 102 waits for a radiation wave sent from the RFID reader 100 at each receiving circuit 122.

[0044] If the reference RFID reader 102 detects a radiated wave (Yes in S701), the process proceeds to S702, where it waits for a reflected wave transmitted from the RFID tag 101 in response to the radiated wave. If the reference RFID reader 102 detects a reflected wave within a predetermined time after detecting the radiated wave (Yes in S702), it proceeds to S703. If the reference RFID reader 102 does not detect a reflected wave within a predetermined time after detecting the radiated wave (No in S702), the reference RFID reader 102 returns the process to S701, where it waits for a radiated wave from the same or another RFID reader 100.

[0045] In S703, the reference RFID reader 102 identifies the received signal strength and the arrival angle of the radiated wave based on the reception result of the radiated wave received in S701. For example, the reference RFID reader 102 may calculate the average value of the received signal strength of the radiated wave received by each receiving circuit 122, and set the average value as the received signal strength of the radiated wave of the reference RFID reader 102. Alternatively, the reference RFID reader 102 may set any one of the maximum value, minimum value, and median value of the received signal strength of the radiated wave received by each receiving circuit 122 as the received signal strength of the radiated wave in S703. Alternatively, the reference RFID reader 102 may set the received signal strength of a specific receiving circuit 122 as the signal strength of the radiated wave in S703. Furthermore, the reference RFID reader 102 may identify the identification information of the RFID reader 100 that transmitted the radiated wave based on the reception result of the radiated wave received in S701.

[0046] In S703, the estimation of the arrival angle is performed by the AoA (Angle of Arrival) method using array antenna technology. The multiple antennas 123 equipped in the reference RFID reader 102 may have different distances from the antenna 114 of the RFID reader 100. In this case, when the reflected wave of the RFID tag 101 reaches the multiple antennas 123, signals of different phases are detected by the respective receiving circuits 122. For this reason, the RF control unit 121 obtains in-phase and quadrature (IQ) samples of the detected signal, and calculates the angle of the RFID tag 101 based on the phase difference of the IQ samples. For example, when the phase of the signal received by the receiving circuit 122a is 1 / 4 wavelength advanced compared to the phase of the signal detected by the receiving circuit 122b, and the wavelength of the emitted wave is 2.5 GHz, that is, the wavelength of the signal is 12 cm, the difference in distance is 3 cm. That is, the difference between the distance from antenna 123a to antenna 114 of RFID reader 100 and the distance from antenna 123b to antenna 114 of RFID reader 100 is 3 cm. In this way, by identifying the difference in distance from each antenna 123 to antenna 114 of RFID reader 100, the direction (arrival angle) from each antenna 123 to RFID reader 100 can be identified.

[0047] The reference RFID reader 102 advances the process to S704, and identifies the identification information, received signal strength, and arrival angle of the RFID tag 101 that sent out the reflected wave based on the reception result of the reflected wave received in S702. In S704, the received signal strength and arrival angle can be identified by a method similar to that described in S703.

[0048] Next, the reference RFID reader 102 advances the process to S705 and transmits the information specified in S703 and S704 to the host controller 103. The reference RFID reader 102 may transmit the information specified in S703 and S704 in multiple packets. In this case, for example, after the process of S703 and before the process of S704, information on the received signal strength and the arrival angle of the RFID reader 100 that transmitted the radiated wave may be transmitted. Alternatively, when information on the signal strength and the arrival angle of the RFID reader 100 that transmitted the radiated wave is identified in S703, information on the received signal strength and the arrival angle of the radiated wave may be transmitted to the host controller 103 in parallel with the process of S704. The reference RFID reader 102 that transmitted the information specified in S703 and S704 to the host controller 103 ends the process shown in FIG. 7.

[0049] 7, the reference RFID reader 102 is described as estimating the arrival angle, but the host controller 103 may estimate the arrival angle. In this case, the reference RFID reader 102 may transmit to the host controller 103 information indicating the phase difference between the radiated wave and the reflected wave received by each receiving circuit.

[0050] 8 is a block diagram showing the configuration of the host controller 103. The host controller 103 includes a control unit 130, a storage unit 131, and an external communication unit 132. The host controller 103 is also connected to an output unit 105. In one example, the host controller 103 is an information processing device such as a personal computer or a smartphone.

[0051] The control unit 130 includes one or more processors such as a CPU and a memory, and executes a program stored in the memory to control the operation of the entire host controller 103. The control unit 130 functions as a first reception result acquisition unit 1301, a second reception result acquisition unit 1302, a reader position estimation unit 1303, a first tag position estimation unit 1304, a second tag position estimation unit 1305, a reference reader position management unit 1306, and a tag position output unit 1307.

[0052] The first reception result acquisition unit 1301 acquires a reception result including information on the received signal strength and arrival angle of the radiated wave transmitted from the RFID reader 100, which is received by the reference RFID reader 102. The first reception result acquisition unit 1301 acquires a reception result including information on the received signal strength and arrival angle of the reflected wave transmitted from the RFID tag 101, which is received by the reference RFID reader 102.

[0053] The second reception result acquisition unit 1302 acquires the reception result including information on the reception signal strength of the reflected wave transmitted from the RFID tag 101 and received by the RFID reader 100 .

[0054] The reader position estimation unit 1303 estimates the position of the RFID reader 100 based on the reception result received by the reference RFID reader 102, which includes information on the reception signal strength and arrival angle of the radiation wave sent from the RFID reader 100.

[0055] The first tag position estimation unit 1304 estimates the position of the RFID tag 101 based on a reception result received by the reference RFID reader 102, the reception result including information on the reception signal strength and the arrival angle of the reflected wave transmitted from the RFID tag 101. The estimation method of the first tag position estimation unit 1304 will be described later with reference to FIG.

[0056] A second tag position estimation unit 1305 estimates the position of the RFID tag 101 based on the position of the RFID reader 100 estimated by the reader position estimation unit 1303 and the received signal strength of the reflected wave received by the RFID reader 100 acquired by the second reception result acquisition unit 1302. The estimation method of the second tag position estimation unit will be described later with reference to FIG.

[0057] The reference reader position management unit 1306 stores the position of the reference RFID reader 102 in the storage unit 131 .

[0058] The tag position output unit 1307 outputs the position of the RFID tag 101 estimated by the first tag position estimation unit 1304 or the second tag position estimation unit 1305 via the output unit 105 or the external communication unit 132 .

[0059] The tag transmission strength estimation unit 1308 acquires the transmission strength of the radiation wave from the RFID reader 100, and estimates the transmission strength of the reflected wave sent from the RFID tag 101 from the reception result of the reflected wave acquired by the second reception result acquisition unit 1302. The estimation method of the tag transmission strength estimation unit 1308 will be described later with reference to FIG.

[0060] 9, the control unit 130 executes a position estimation process for the RFID tag 101. The control unit 130 controls the output unit 105 to output the estimated position of the RFID tag 101. In one example, the control unit 130 may transmit the estimated position of the RFID tag 101 to an external device via the external communication unit 132.

[0061] The memory unit 131 is a storage device that stores programs executed by the control unit 130 and information received from the RFID reader 100 and the reference RFID reader 102. The memory unit 131 also stores the position of the RFID tag 101 estimated by the control unit 130 in association with the identification information of the RFID tag 101. The external communication unit 132 is a communication unit that operates in accordance with the standards of wired or wireless LAN and Bluetooth (registered trademark) that can communicate with the RFID reader 100 and the reference RFID reader 102.

[0062] The output unit 105 is an output interface, such as a display or a speaker, for outputting information to a user from the control unit 130 of the host controller 103. The output unit 105 according to this embodiment outputs the position of the RFID tag 101 estimated by the host controller 103.

[0063] Fig. 9 is a flowchart showing an example of processing for estimating the position of an RFID tag, executed by the host controller 103. The processing shown in Fig. 9 is executed after the host controller 103 issues an instruction to the RFID reader 100 and the reference RFID reader 102 to execute processing for estimating the position of the RFID tag 101. The processing shown in Fig. 9 is realized by the processor of the control unit 130 of the host controller 103 executing a program stored in the memory.

[0064] In S901, the host controller 103 acquires radiated wave information and reflected wave information from the reference RFID reader 102. Then, in S902, the host controller 103 acquires from the RFID reader 100 the reception result of the reflected wave received by the RFID reader 100. Note that the processes of S901 and S902 may be performed in any order, or may be performed in parallel.

[0065] Next, in S903, the host controller 103 determines from the reception result acquired from the reference RFID reader 102 whether or not the reception signal strength of the reflected wave received by the reference RFID reader 102 from the RFID tag 101 is equal to or greater than a threshold value.

[0066] If the received signal strength of the reflected wave from the RFID tag 101 received by the reference RFID reader 102 is equal to or greater than the threshold (Yes in S903), the host controller 103 advances the process to S904. In S904, the host controller 103 estimates the position of the RFID tag 101 based on the received signal strength and the angle of arrival detected by the reference RFID reader 102.

[0067] Here, a calculation method for estimating the position of the RFID tag 101 based on the received signal strength of the reflected wave received by the reference RFID reader 102 will be described with reference to FIG.

[0068] FIG. 10 is a diagram showing a method for estimating the position of the RFID tag 101 when the received signal strength of the reflected wave from the RFID tag 101 read by the reference RFID reader 102 is equal to or greater than a threshold value.

[0069] 7 and S901 in Fig. 9, the host controller 103 has information on the angle of arrival and the received signal strength for identifying the angle a [°] and the distance b [m] from the reference RFID reader 102 to the RFID tag 101. Also, it is assumed that the host controller 103 has the position information of the reference RFID reader 102 in advance.

[0070] Here, the output power of the reflected wave sent out by the RFID tag 101 can vary depending on the distance from the RFID reader 100. Therefore, information on the output power of the RFID tag 101 is required to estimate the distance b [m]. Therefore, the output power of the RFID tag 101 is found from the received power of the radiated wave received by the RFID tag 101 from the RFID reader 100.

[0071] FIG. 11 shows an example of a method for calculating the transmission strength of the reflected wave from the RFID tag 101 based on the reception signal strength of the reflected wave received by the RFID reader 100 from the RFID tag 101. In FIG.

[0072] In the example of Fig. 11, the RFID reader 100 will be described as sending out a radiated wave with a transmission power of 24 [dBm]. The received power of the RFID tag 101 is attenuated by X [dB] due to spatial attenuation and antenna gain. When sending out a reflected wave from the RFID tag 101, the power is attenuated by -9 [dB] due to losses including reflection loss and circuit loss, in the example of Fig. 11, and the transmission strength of the reflected wave becomes Y [dBm]. In other words, it can be calculated as Y = 24 - X - 9 [dBm].

[0073] If the signal strength received by the RFID reader 100 is -49 [dBm], then YX can be calculated as -49. By substituting Y = 24 - X - 9, 24 - 2X - 9 = -49 can be obtained, and X = -32 [dB] can be determined.

[0074] In this way, it is possible to determine the spatial attenuation from the RFID reader 100 to the RFID tag 101 based on the received signal strength of the reflected wave received by the RFID reader 100 that emitted the radiated wave, and to determine the received signal strength of the radiated wave received by the RFID tag 101. Also, it is possible to estimate the transmission strength of the reflected wave emitted by the RFID tag 101 based on the received signal strength of the radiated wave received by the RFID tag 101.

[0075] Here, the reference RFID reader 102 may use an antenna 123 having directivity. In such a case, the reference RFID reader 102 may have information on the directivity of the antenna 123 in advance, and may correct the received signal strength based on the information on the directivity of the antenna 123 after specifying the angle a [°] to the RFID tag 101 by AoA. For example, in the example of FIG. 11, if the gain of the antenna 123 is 4 [dB], X=-34 [dB] can be specified as 24-2X-9=-49-4. Since the RFID tag 101 uses a small antenna, the gain of the antenna is assumed to be a fixed value. Also, the RFID reader 100 may be assumed to be omnidirectional in the horizontal plane.

[0076] FIG. 12 is a table showing the correspondence relationship between the estimated distance b [m] between the RFID tag 101 and the reference RFID reader and the received signal strength when the transmission strength of the reflected wave sent from the RFID tag 101 is −20 [dBm].

[0077] As described with reference to FIG. 11, the host controller 103 can obtain the reflected wave output power of the RFID tag 101 from the received power of the reflected wave from the RFID tag 101 of the RFID reader 100. Therefore, as shown in the table of FIG. 13, an offset is applied to the received signal strength according to the reflected wave output power of the RFID tag 101, and an estimated distance b [m] can be obtained based on the received signal strength of the reflected wave received by the reference RFID reader 102. For example, when the reference RFID reader 102 receives the reflected wave from the RFID tag 101 with a received power of −65.7 dBm, if the reflected wave output power of the RFID tag 101 is −20 dBm, the distance is 5.0 m. Therefore, the host controller 103 determines that the distance between the reference RFID reader 102 and the RFID tag 101 is 5 m. On the other hand, if the reflected wave output power of the RFID tag 101 is −15 dBm and the received signal power of the reference RFID reader 102 is −65.7 dBm, the RSSI is −70.7 dBm. Therefore, it can be determined that the distance between the reference RFID reader 102 and the RFID tag 101 is 8.5 to 9.0 m.

[0078] As described above, in S904, the host controller 103 can estimate the transmission strength of the reflected wave transmitted from the RFID tag 101 from the transmission signal strength and the received signal strength received by the RFID reader 100. Also, in S904, the host controller 103 can estimate the position of the RFID tag 101 from the received signal strength and arrival angle of the reflected wave received by the reference RFID reader 102 and the transmission strength of the reflected wave transmitted from the RFID tag 101.

[0079] In S905, the host controller 103 stores the position information of the RFID tag 101 estimated in S904 in the storage unit 131 in association with the identification information of the RFID tag 101 received from the reference RFID reader 102 or the RFID reader 100. In S905, as shown in the lower part of FIG. 10, at least one of the estimated identification information and position information of the RFID tag 101 may be notified to the user via the output unit 105. The reference RFID reader 102 may also be displayed together. The distance and angle from the reference RFID reader 102 to the RFID tag 101 may also be displayed on the output unit 105.

[0080] In another example, the transmission signal strength of the RFID tag 101 may be estimated in consideration of the directivity of the RFID reader 100. For example, after estimating the position of the RFID tag 101 with reference to FIG. 10, the relative angle between the RFID reader 100 and the RFID tag 101 can be specified based on the position of the RFID reader 100. Then, the angle of the RFID tag 101 as seen from the RFID reader 100 can be estimated based on the output of a sensor (not shown) such as a geomagnetic sensor. Then, the host controller 103 can estimate the antenna gain at the angle of the RFID tag 101 as seen from the RFID reader 100 from information on the antenna directivity of the RFID reader 100. Then, the host controller 103 can correct the transmission strength of the RFID tag 101 based on the estimated antenna gain of the RFID reader 100, and estimate the amount of attenuation between the reference RFID reader 102 and the RFID tag 101 based on the corrected transmission strength. This makes it possible to estimate the position of the RFID tag 101 more accurately by taking into account the directivity of the RFID reader 100.

[0081] If the received signal strength of the reflected wave received by the reference RFID reader 102 is lower than the predetermined threshold value (No in S903), the host controller 103 advances the process to S906.

[0082] The received signal strength of the reflected wave from the RFID tag 101 read by the reference RFID reader 102 affects the accuracy of position estimation. For example, when the distance between the RFID tag 101 and the reference RFID reader 102 increases, the received signal strength decreases, and the difference between the thermal noise and the noise floor due to the NF (Noise Figure) characteristics of the receiving circuit becomes smaller. That is, when the received signal strength of the reflected wave approaches the noise floor, the received signal strength detected by the reference RFID reader 102 changes more greatly due to the change in the intensity of the random noise compared to when the received signal strength of the reflected wave is large. As a result, the received signal strength detected by the reference RFID reader 102 is affected by the random noise, and the accuracy of the read received signal strength of the reflected wave decreases. For example, in the table of FIG. 12, when the received signal strength is −70.8 dBm, the distance is estimated to be 9 m, but when the received signal strength decreases by 1 dB, it is estimated to be −71.8 dBm, that is, the distance is estimated to be 10 m. That is, the accuracy of the position estimation may decrease.

[0083] Furthermore, when the received signal strength of the reflected wave approaches the noise floor, it also affects the phase synchronization accuracy, and the phase detection accuracy of the reflected wave decreases. As a result, the accuracy of the arrival angle estimated based on the phase of the reflected wave also changes depending on the received signal strength. For example, as shown in Figure 14, if a=40[°] changes by ±5[°], a position shift of approximately 2.3 m occurs when b=10 m. This can decrease the accuracy of the position estimation.

[0084] Therefore, in this embodiment, the host controller 103 estimates the position of the RFID tag 101 based on the reflected wave information obtained from the RFID reader 100 when the received signal strength of the reflected wave received by the reference RFID reader 102 in S903 is lower than a predetermined threshold value.

[0085] 9, the host controller 103 estimates the position of the RFID reader 100 based on the reception result of the radiated wave received by the reference RFID reader 102. Specifically, in S906, the host controller 103 estimates the position of the RFID reader 100 from the received signal strength and arrival angle of the radiated wave included in the reception result acquired from the reference RFID reader 102, and the transmitted signal strength of the radiated wave from the RFID reader 100. The estimation method can be the same as that described with reference to FIG. 10, except that the device that transmits the wireless signal is the RFID reader 100 and the device that receives it is the reference RFID reader 102, and therefore a description thereof will be omitted.

[0086] Next, in S907, the host controller 103 estimates the distance between the RFID reader 100 and the RFID tag 101 based on the received signal strength of the reflected wave included in the reflected wave information acquired from the RFID reader 100. In S907, the estimation can be performed in the same manner as described with reference to Fig. 10, except that the device that transmits the radio wave is the RFID tag 101 and the device that receives it is the RFID reader 100. Note that it may be determined based on the identification information of the RFID tag 101 that the reflected wave, the received signal strength of which is determined in S903 to be equal to or greater than a threshold, and the reflected wave from the RFID tag 101, the distance of which is estimated in S907, are reflected waves transmitted from the same RFID tag 101.

[0087] Next, in S908, the host controller 103 estimates the position of the RFID tag 101 from the distance between the RFID reader 100 and the RFID tag 101 estimated in S907 and the position of the RFID reader 100 estimated in S906.

[0088] 15 shows the estimation process in S908. As described above, the host controller 103 estimates the distance b [m] and angle a [°] to the RFID reader 100 that sent out the radiated wave in S907, and specifies the distance c [m] to the RFID tag 101 that sent out the reflected wave in S908. Here, since the host controller 103 does not know the angle of the RFID tag 101 with respect to the RFID reader 100, it determines that the position of the RFID tag 101 is within a circle of distance c [m] centered on the RFID reader 100.

[0089] 10. Therefore, in the map display displayed by the output unit 105, as shown in the lower part of FIG. 15, the RFID tag 101 is displayed as a circle indicating a larger range compared to the map display shown in the lower part of FIG.

[0090] In this way, by using reflected wave information from an RFID reader 100 with a higher received signal strength than the reference RFID reader 102, it is possible to prevent a decrease in accuracy when estimating the position of an RFID tag 101 located far away from the reference RFID reader 102.

[0091] In S905, the position information of the RFID tag 101 stored in the storage unit 131 may be the coordinates (XY coordinates or XYZ coordinates in FIG. 3) of the RFID tag 101. Alternatively, the angle a [°] and the distance b [m] may be registered based on a reference RFID reader having coordinate information in advance.

[0092] 10 and 14, the estimated position of the RFID tag 101 is output as being illustrated on a map image, but it may be simply displayed, for example, by only the numerical values ​​of the coordinate information when applied to a preset coordinate system. That is, the method of outputting the estimated position information is not limited to the method of this embodiment. For example, the position of the RFID tag 101 may be output by a method other than a screen display, such as a voice output or a blinking pattern of an LED lamp (not shown) of the host controller 103.

[0093] As described above, when the received signal strength of the reflected wave received by the reference RFID reader 102 is equal to or greater than a predetermined threshold, the position of the RFID tag 101 is estimated based on the received signal strength and the arrival angle of the reflected wave received by the reference RFID reader 102. When the received signal strength of the reflected wave received by the reference RFID reader 102 is less than the predetermined threshold, the position of the RFID reader 100 is estimated based on the received signal strength and the arrival angle of the radiated wave received by the reference RFID reader 102. Then, the position of the RFID tag 101 is estimated based on the estimated position of the RFID reader 100 and the received signal strength of the reflected wave received by the RFID reader. This makes it possible to estimate the position of the RFID tag 101 with high accuracy and provide the estimated position to the user even if the reference RFID reader 102 is separated from the RFID tag 101.

[0094] Second Embodiment In the second embodiment, there are a plurality of RFID readers for one reference RFID reader. Note that the same reference numerals are used for the same configurations, functions, and processes as those in the first embodiment, and the description thereof will be omitted.

[0095] Fig. 16 shows an information processing system according to the second embodiment. A wireless communication system 1601 shown in Fig. 16 includes a plurality of RFID tags 1011-101i and a plurality of RFID readers 1001-100j. The RFID tags 1011-101i are referred to as RFID tags 101 without distinction, and the RFID readers 1001-100j are referred to as RFID readers 100 without distinction. The configuration is similar to that of the first embodiment, so a description thereof will be omitted.

[0096] The process of estimating the position of the RFID tag 101 by the reference RFID reader 102 is the same as that in the first embodiment, and therefore a description thereof will be omitted. By using a plurality of reference RFID readers 102, the time required for reading the RFID tag 101 can be shortened.

[0097] When multiple RFID readers 100 operate within close range, radio interference of UHF-band radiation waves emitted from the RFID readers 100 becomes an issue. The reflected waves of the RFID tags 101 have a smaller power than the radiation waves emitted from the RFID readers 100, so there is a possibility that communication will become impossible due to interference. Generally, radiation waves and reflected waves are separated in space, time, or frequency, but in the wireless communication system 1601 in which the RFID readers 100 and RFID tags 101 are expected to move, separation is performed in time rather than spatially.

[0098] For the time separation, an interference avoidance technique called LBT (Listen Before Talk) is adopted. Before transmitting a radiated wave, the RFID reader 100 performs carrier sense for 5 milliseconds or more to check whether the frequency band (channel) including the frequency band for transmitting the radiated wave is not being used by another RFID reader 100 or an external communication system. If the carrier sense result indicates that the channel is occupied, the RFID reader 100 does not transmit the radiated wave for 4 seconds after the detection. If the channel is determined to be vacant, the RFID reader 100 transmits the radiated wave for a maximum of 4 seconds. After transmitting the radiated wave, the RFID reader 100 does not transmit the radiated wave until a transmission pause time of 50 milliseconds has elapsed. In this way, by using LBT, even when multiple RFID readers are operating in close range, it is possible to estimate the position of the RFID tag while avoiding radio wave interference by using time separation. The method of displaying the estimated position information is the same as that of the first embodiment, so a description thereof will be omitted.

[0099] Furthermore, the RFID tag 101 has an anti-collision function, and transmits a reflected wave at a timing designated by the RFID reader 100 for each RFID tag 101. In this case, the radiated wave may include identification information of the RFID tag 101 and information designating the timing at which the RFID tag 101 corresponding to the identification information transmits a reflected wave. Alternatively, the RFID tag 101 may transmit a reflected wave at a timing delayed based on a pseudo-random function determined by the RFID tag 101 or at a timing delayed according to the identifier of the RFID tag 101, separate from the radiated wave. This allows <Third embodiment> In the third embodiment, the RFID reader has multiple antennas and detects the reception strength and arrival angle of the reflected wave. Note that the same reference numerals are used for the same configurations, functions, and processes as those in the first embodiment, and the description will be omitted.

[0100] The RFID reader 100 according to this embodiment has multiple antennas and receiving circuits, and can detect the received signal strength and phase of the reflected waves acquired by the multiple antennas, just like the reference RFID reader 102 shown in Fig. 6. The arrival angle can be identified by observing the change in the phase of the reflected waves acquired by each antenna.

[0101] 17 shows a tag position estimation method according to this embodiment. As described with reference to S703, the reference RFID reader 102 receives the radiated wave sent from the RFID reader 100, and estimates the distance b and the arrival angle a from the received signal strength and phase of the radiated wave. The RFID reader 100 also receives the reflected wave sent from the RFID tag 101, and estimates the distance d and the arrival angle c from the received signal strength and phase of the reflected wave. The host controller 103 can estimate the position of the RFID tag 101 by acquiring the reception results including the distance b and the arrival angle a as well as the distance d and the arrival angle c from the reference RFID reader 102 and the RFID reader 100.

[0102] This makes it possible to estimate the position of the RFID tag 101 with higher accuracy.

[0103] <Other embodiments> The above-described embodiment may be modified. For example, at least a part of the functions of the host controller 103 may be provided in the reference RFID reader 102. In this case, the reference RFID reader 102 may include a display unit 105.

[0104] At least one of the RFID reader 100 and the reference RFID reader 102 may estimate the distance to the source of the radiated wave or reflected wave from the received signal strength of the radiated wave or reflected wave. Alternatively, at least one of the RFID reader 100 and the reference RFID reader 102 may estimate the arrival angle to the source of the radiated wave or reflected wave from the phase of the radiated wave or reflected wave. In this case, the reception results transmitted from the reference RFID reader 102 and the RFID reader 100 to the host controller 103 may include the distance to the source of the radiated wave or reflected wave and the arrival angle.

[0105] In the present embodiment, the radiated wave includes the identification information of the RFID reader 100, and the reflected wave includes the identification information of the RFID tag 101. This allows the reception result of the radiated wave to include the identification information of the RFID reader 100 and the reception result of the reflected wave to include the identification information of the RFID tag 101, and the reception result can be selected when estimating the position of a specific RFID tag 101. However, the host controller 103 may instruct a specific RFID reader 100 to transmit a radiated wave or instruct a specific RFID tag 101 to transmit a reflected wave. In this case, at least one of the radiated wave and the reflected wave may not include the identification information of the RFID reader 100 and the RFID tag 101. For example, before S201 in FIG. 2, the host controller 103 transmits an instruction to the RFID reader 100 to measure the position of the RFID tag 101 by specifying the identification information of the RFID tag 101. Next, in S201, the RFID reader 100 transmits a radiated wave by designating the identification information of the RFID tag 101. In this case, only the RFID tag 101 having identification information matching the identification information of the radiated wave transmits a reflected wave, so the reflected wave does not need to include the identification information of the RFID tag 101.

[0106] The present invention can also be realized by a process in which a program for implementing one or more of the functions of the above-described embodiments is supplied to a system or device via a network or a storage medium, and one or more processors in a computer of the system or device read and execute the program. The present invention can also be realized by a circuit (e.g., ASIC) that implements one or more of the functions.

[0107] [Summary of the embodiment] The disclosure of this embodiment is as follows.

[0108] (Item 1) An information processing device, a first acquiring means for acquiring information on a received signal strength at a transceiver of a reflected wave transmitted in response to a radiated wave transmitted from the transceiver when a passive tag is present; A second acquisition means for acquiring information regarding a received signal strength and an arrival angle of the radiation wave received by a reference receiver; a third acquisition means for acquiring a position of the reference receiver; a first estimation means for estimating a position of the transceiver based on the position of the reference receiver acquired by the third acquisition means and information regarding the received signal strength and the angle of arrival of the emitted wave acquired by the second acquisition means; a second estimation means for estimating a position of the passive tag based on the position of the transceiver estimated by the first estimation means and information on the received signal strength of the reflected wave acquired by the first acquisition means; An information processing device comprising:

[0109] (Item 2) The second acquisition means further acquires information regarding a received signal strength and an arrival angle of the reflected wave received by the reference receiver; 2. The information processing device according to item 1, further comprising a third estimation means for estimating a position of the passive tag based on a received signal strength and an angle of arrival of the reflected wave received by the reference receiver.

[0110] (Item 3) When the received signal strength of the reflected wave acquired by the second acquisition means is less than a predetermined threshold, the second estimation means estimates the position of the passive tag; 3. The information processing device according to item 2, wherein the position of the passive tag is estimated by the third estimation means when the received signal strength of the reflected wave acquired by the second acquisition means is equal to or greater than the predetermined threshold.

[0111] (Item 4) The first acquisition means further acquires identification information of the passive tag that transmitted the reflected wave received by the transceiver, The second acquisition means further acquires identification information of the passive tag that transmitted the reflected wave received by the reference receiver, The second estimation means estimates a position of a passive tag having specific identification information based on the identification information acquired by the first acquisition means and the second acquisition means; 4. The information processing device according to item 2 or 3, wherein the third estimation means estimates a position of a passive tag having specific identification information based on the identification information acquired by the second acquisition means.

[0112] (Item 5) 5. The information processing device according to any one of items 1 to 4, wherein the reference receiver has a plurality of antennas and determines the angle of arrival based on a phase difference between the radio signals received by each of the plurality of antennas.

[0113] (Item 6) Further, a fourth acquisition means for acquiring a transmission intensity of a radiation wave transmitted by the transceiver is provided, The information processing device described in any one of items 1 to 5, characterized in that the first estimation means estimates the distance between the transceiver and the reference receiver based on the received signal strength of the radiated wave received by the reference receiver acquired by the second acquisition means and the transmission strength of the radiated wave acquired by the fourth acquisition means.

[0114] (Item 7) a fourth estimation means for estimating a transmission strength of the reflected wave transmitted by the passive tag based on the transmission strength of the radiated wave transmitted by the transceiver, acquired by the fourth acquisition means, and the reception signal strength of the reflected wave received by the transceiver, acquired by the first acquisition means; 7. The information processing device according to item 6, wherein the second estimation means estimates the position of the passive tag further based on the transmission intensity of the reflected wave estimated by the fourth estimation means.

[0115] (Item 8) 8. The information processing device according to any one of items 1 to 7, wherein the passive tag has an anti-collision function that adjusts the time between receiving the emitted wave and sending out the reflected wave.

[0116] (Item 9) 9. The information processing device according to any one of items 1 to 8, further comprising a display unit that displays to a user the position of the passive tag estimated by the second estimation unit.

[0117] (Item 10) 10. The information processing device according to item 9, wherein the display means displays the position of the passive tag in association with the position of the reference receiver acquired by the third acquisition means.

[0118] (Item 11) 11. The information processing device according to any one of items 1 to 10, wherein the maximum gain of the antenna of the reference receiver is higher than the maximum gain of the antenna of the transmitter / receiver.

[0119] (Item 12) the reference receiver obtains information regarding a received signal strength of a reflected wave received by the transceiver at a frequency different from a frequency at which the emitted wave is transmitted from the transceiver; 12. The information processing device according to any one of items 1 to 11, wherein the first acquisition means acquires information regarding a received signal strength of a reflected wave received by the transceiver from the reference receiver.

[0120] (Item 13) 13. The information processing device according to any one of items 1 to 12, wherein the transceiver is a mobile terminal.

[0121] (Item 14) 14. The information processing device according to any one of items 1 to 13, characterized in that the information processing device is provided in the reference receiver.

[0122] (Item 15) The transceiver has a plurality of antennas; The first acquisition means acquires information regarding a received signal strength and an arrival angle of a reflected wave transmitted in response to the emitted wave when a passive tag is present; The information processing device described in any one of items 1 to 14, characterized in that the second estimation means estimates the position of the passive tag based on the position of the transceiver estimated by the first estimation means and information regarding the received signal strength and arrival angle of the reflected wave acquired by the first acquisition means.

[0123] (Item 16) An information processing system comprising a transceiver and a reference receiver, The transceiver transmits a radiation wave, and if a passive tag is present, receives a reflected wave transmitted in response to the radiation wave transmitted from the transceiver; The reference receiver receives the emitted wave, The information processing system includes: a first acquisition means for acquiring information regarding a received signal strength of the reflected wave received by the transceiver; a second acquiring means for acquiring information regarding a received signal strength and an arrival angle of the radiation wave received by the reference receiver; a third acquisition means for acquiring a position of the reference receiver; a first estimation means for estimating a position of the transceiver based on the position of the reference receiver acquired by the third acquisition means and information regarding the received signal strength and the angle of arrival of the emitted wave acquired by the second acquisition means; a second estimation means for estimating a position of the passive tag based on the position of the transceiver estimated by the first estimation means and information on the received signal strength of the reflected wave acquired by the first acquisition means; An information processing system comprising:

[0124] (Item 17) An information processing method of an information processing device, acquiring information about a received signal strength at a transceiver of a reflected wave sent in response to a radiated wave sent from the transceiver when a passive tag is present; obtaining information regarding received signal strength and angle of arrival of said radiation received by a reference receiver; acquiring a position of the reference receiver; estimating a position of the transceiver based on the acquired position of the reference receiver and the acquired information on the received signal strength and the angle of arrival of the emitted wave; estimating a position of the passive tag based on the estimated position of the transceiver and the acquired information on the received signal strength of the reflected wave; 13. An information processing method comprising:

[0125] (Item 18) The computer of the information processing device a first acquisition step of acquiring information on a received signal strength at a transceiver of a reflected wave transmitted in response to a radiated wave transmitted from the transceiver when a passive tag is present; a second acquisition step of acquiring information regarding the received signal strength and the arrival angle of the radiation wave received by a reference receiver; a third acquisition step of acquiring the position of the reference receiver; a first estimation step of estimating a position of the transceiver based on the position of the reference receiver acquired in the third acquisition step and information on the received signal strength and the arrival angle of the emitted wave acquired in the second acquisition step; a second estimation step of estimating a position of the passive tag based on the position of the transceiver estimated in the first estimation step and information on the received signal strength of the reflected wave acquired in the first acquisition step; A program characterized by executing the above.

[0126] The invention is not limited to the above-described embodiments, and various modifications and variations are possible without departing from the spirit and scope of the invention. Accordingly, the following claims are appended to apprise the public of the scope of the invention. [Explanation of symbols]

[0127] 1 wireless communication system, 100 RFID reader, 101 RFID tag, 102 reference RFID reader, 103 host controller

Claims

1. An information processing device, a first acquiring means for acquiring, when a passive tag is present, information on the strength of a signal received by the transceiver of a reflected wave transmitted from the passive tag in response to a radiated wave transmitted from the transceiver; a second acquiring means for acquiring information about the received signal strength and the angle of arrival of the radiation wave received by the reference receiver; a third acquisition means for acquiring the position of the reference receiver; a first estimation means for estimating a position of the transceiver based on the position of the reference receiver acquired by the third acquisition means and information regarding the received signal strength and the angle of arrival of the emitted wave acquired by the second acquisition means; a second estimation means for estimating the position of the passive tag based on the position of the transceiver estimated by the first estimation means and information on the received signal strength of the reflected wave acquired by the first acquisition means; An information processing device comprising:

2. the second acquisition means further acquires information regarding the received signal strength and the arrival angle of the reflected wave received by the reference receiver; 2. The information processing apparatus according to claim 1, further comprising a third estimation means for estimating the position of the passive tag based on the received signal strength and angle of arrival of the reflected wave received by the reference receiver.

3. When the received signal strength of the reflected wave acquired by the second acquisition means is less than a predetermined threshold, the second estimation means estimates the position of the passive tag; 3. The information processing apparatus according to claim 2, wherein the position of the passive tag is estimated by the third estimation means when the received signal strength of the reflected wave acquired by the second acquisition means is equal to or greater than the predetermined threshold value.

4. The first acquisition means further acquires identification information of the passive tag that transmitted the reflected wave received by the transceiver, The second acquisition means further acquires identification information of the passive tag that transmitted the reflected wave received by the reference receiver, the second estimation means estimates a position of a passive tag having specific identification information based on the identification information acquired by the first acquisition means and the second acquisition means; 3. The information processing apparatus according to claim 2, wherein the third estimation means estimates the position of a passive tag having specific identification information based on the identification information acquired by the second acquisition means.

5. 2. The information processing apparatus according to claim 1, wherein the reference receiver has a plurality of antennas, and the arrival angle is determined based on a phase difference between the radio signals received by the plurality of antennas.

6. a fourth acquisition means for acquiring a transmission intensity of a radiation wave transmitted by the transceiver; 2. The information processing device according to claim 1, wherein the first estimation means estimates the distance between the transceiver and the reference receiver based on the received signal strength of the radiated wave received by the reference receiver, which is acquired by the second acquisition means, and the transmission strength of the radiated wave, which is acquired by the fourth acquisition means.

7. a fourth estimation means for estimating the transmission strength of the reflected wave transmitted by the passive tag based on the transmission strength of the radiated wave transmitted by the transceiver, which is acquired by the fourth acquisition means, and the received signal strength of the reflected wave received by the transceiver, which is acquired by the first acquisition means; 7. The information processing apparatus according to claim 6, wherein the second estimation means estimates the position of the passive tag further based on the transmission intensity of the reflected wave estimated by the fourth estimation means.

8. 2. The information processing apparatus according to claim 1, wherein the passive tag has an anti-collision function for adjusting the time between receiving the emitted wave and transmitting the reflected wave.

9. 2. The information processing apparatus according to claim 1, further comprising a display unit that displays to a user the position of the passive tag estimated by the second estimation unit.

10. 10. The information processing apparatus according to claim 9, wherein the display means displays the position of the passive tag in association with the position of the reference receiver acquired by the third acquisition means.

11. 2. The information processing apparatus according to claim 1, wherein the maximum gain of the antenna of the reference receiver is higher than the maximum gain of the antenna of the transmitter / receiver.

12. the reference receiver obtains information about the received signal strength of a reflected wave received by the transceiver at a frequency different from the frequency at which the emitted wave is transmitted from the transceiver; 2. The information processing apparatus according to claim 1, wherein the first acquisition means acquires, from the reference receiver, information relating to the received signal strength of the reflected wave received by the transceiver.

13. 2. The information processing apparatus according to claim 1, wherein the transceiver is a mobile terminal.

14. 2. The information processing device according to claim 1, wherein the information processing device is provided in the reference receiver.

15. the transceiver has a plurality of antennas; the first acquisition means acquires information regarding the received signal strength and the arrival angle of a reflected wave transmitted from the passive tag in response to the emitted wave when the passive tag is present; The information processing device described in claim 1, characterized in that the second estimation means estimates the position of the passive tag based on the position of the transceiver estimated by the first estimation means and information regarding the received signal strength and angle of arrival of the reflected wave acquired by the first acquisition means.

16. An information processing system comprising a transceiver and a reference receiver, the transceiver transmits a radiated wave, and if a passive tag is present, receives a reflected wave transmitted from the passive tag in response to the radiated wave transmitted from the transceiver; the reference receiver receives the emitted wave; The information processing system includes: a first acquisition means for acquiring information regarding the received signal strength of the reflected wave received by the transceiver; a second acquisition means for acquiring information about the received signal strength and the arrival angle of the radiation wave received by the reference receiver; a third acquisition means for acquiring the position of the reference receiver; a first estimation means for estimating a position of the transceiver based on the position of the reference receiver acquired by the third acquisition means and information regarding the received signal strength and the angle of arrival of the radiated wave acquired by the second acquisition means; a second estimation means for estimating the position of the passive tag based on the position of the transceiver estimated by the first estimation means and information on the received signal strength of the reflected wave acquired by the first acquisition means; An information processing system comprising:

17. An information processing method for an information processing device, When a passive tag is present, acquiring information regarding the strength of a signal received by the transceiver of a reflected wave transmitted from the passive tag in response to a radiation wave transmitted from the transceiver; obtaining information regarding received signal strength and angle of arrival of the radiation received by a reference receiver; obtaining the position of the reference receiver; estimating a position of the transceiver based on the acquired position of the reference receiver and the acquired information on the received signal strength and angle of arrival of the emitted wave; estimating the location of the passive tag based on the estimated location of the transceiver and the acquired information on the received signal strength of the reflected wave; An information processing method comprising:

18. The computer of the information processing device a first acquisition step of acquiring, when a passive tag is present, information regarding the strength of a signal received by the transceiver of a reflected wave transmitted from the passive tag in response to a radiation wave transmitted from the transceiver; a second acquisition step of acquiring information about the received signal strength and the angle of arrival of the radiation wave received by the reference receiver; a third acquisition step of acquiring the position of the reference receiver; a first estimation step of estimating a position of the transceiver based on the position of the reference receiver acquired in the third acquisition step and information on the received signal strength and the angle of arrival of the emitted wave acquired in the second acquisition step; a second estimation step of estimating the position of the passive tag based on the position of the transceiver estimated in the first estimation step and information on the received signal strength of the reflected wave acquired in the first acquisition step; A program characterized by executing the following.

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