JP4974084B2 - Wireless ID tag system - Google Patents

Description

  The present invention relates to a wireless ID (Identification) tag system, and in particular, a wireless ID tag system for acquiring ID information from a predetermined wireless ID tag among a plurality of wireless ID tags that can exist within a short distance, and a wireless ID The present invention relates to a tag acquisition method and a wireless ID tag acquisition program.

  Various types of wireless ID tag systems of this type have been conventionally devised. For example, the following techniques are well known. The first is to provide a gate for passing an article or person wearing an RFID (Radio Frequency Identification) tag and adjust the reading range by changing the transmission power value of the signal transmitted from the RFID reader / writer device. Thus, only the RFID tag that has passed through the gate is read, and the RFID tag outside the gate is not read as an unnecessary tag.

  The second is to adjust the reading range by adjusting the mounting angle of the antenna for transmitting and receiving signals between the RFID reader / writer device and the RFID tag for each installation location, thereby changing the directivity.

  The third is that the antenna is housed in a metal casing, and the reading range is adjusted using a radio wave absorber or a radio wave reflector (all of which are not related to the inventions known in the literature). ).

  Also, in the literature, an RFID tag that is present in a predetermined area is determined by transmitting a read signal to the RFID tag and comparing the power value of the response signal received from the RFID tag with a reference power value. An RFID reader device and an RFID system that acquire ID information when it is determined that an RFID tag is present in a predetermined area are known (see, for example, Patent Document 1).

JP2007-323423 (2nd page, FIG. 2)

  However, in the prior art 1, since the reading range is adjusted by changing the transmission power value, the radio wave in the gate is weakened, so that the originally required reading rate in the gate is deteriorated. Furthermore, although the reduction range of the transmission power value is determined by the Radio Law, the transmission power value cannot be adjusted because the distance between the gates is short in a place where a plurality of gates are provided, such as a dock door.

  Moreover, in the prior art 2, since an antenna angle is adjusted for every installation place, much adjustment time is required. Further, when the adjustment is made so that the reading range of the unnecessary tag is set, the reading rate is deteriorated because the deviation is from the optimum antenna angle.

  Moreover, in the prior art 3, since a radio wave absorber or a radio wave reflector is used, the apparatus becomes large and a large installation space is required.

  Further, in the technique described in Patent Document 1, the RFID tag existing in a predetermined region is determined by comparing the power value of the response signal received from the RFID tag and the reference power value. When the wireless ID tag approaches, the difference between the power values of the response signals becomes small, and it becomes difficult to determine whether or not the RFID tag exists in a predetermined area. is there.

  Furthermore, since the comparison with the reference power value is performed only by the power value of the response signal, when the RFID tag moves in a predetermined area, the response signal becomes a waveform with a large fluctuation with reflection, and the power value If the reference power value is temporarily exceeded, there is a second problem that the RFID tag is misidentified as existing in a predetermined area.

  Accordingly, an object of the present invention is to provide a wireless ID tag system capable of solving all the above problems and obtaining ID information only from a desired wireless ID tag by filtering the received ID information of unnecessary tags. Is to provide.

The wireless ID tag system of the present invention is a wireless ID tag system that acquires ID information from a wireless ID tag that exists in a communication area. Means for acquiring ID information from a response signal from the ID tag, and means for obtaining desired ID information by performing filtering that excludes unnecessary ID information of the wireless ID tag from the ID information .

A first wireless ID tag system of the present invention is a wireless ID tag system that acquires ID information from a wireless ID tag that passes through a gate ; means for emitting a read signal when the wireless ID tag enters the gate; It means for obtaining the ID information by receiving a response signal from all of the wireless ID tag to the signal, comprising means for obtaining a received signal strength of the response signal; the predetermined value or more peaks in the received signal strength is a predetermined time A means for determining that a wireless ID tag other than one wireless ID tag is unnecessary, and a means for performing filtering to delete unnecessary wireless tag ID information from all received wireless ID tag ID information. It is characterized by.

  The second wireless ID tag system of the present invention in more detail is a wireless ID tag system that acquires ID information from wireless ID tags that pass through a plurality of adjacent gates; for each gate, the wireless ID tag enters the gate. And means for emitting the first read signal, means for emitting the second read signal simultaneously with the first read signal toward the outside of the gate through which the wireless ID tag passes, and all of the first read signal Means for receiving a response signal from the wireless ID tag and acquiring ID information; and means for receiving response signals from all the wireless ID tags for the second read signal and acquiring ID information; And a means for performing filtering for subtracting ID information based on a response signal for the second read signal from ID information based on a response signal for the first read signal.

  The third wireless ID tag system of the present invention in more detail is a wireless ID tag system that acquires ID information from wireless ID tags that pass through a plurality of adjacent gates; for each gate, the wireless ID tag enters the gate. And means for emitting a first read signal, means for receiving response signals from all wireless ID tags for the first read signal and acquiring ID information, and means for acquiring received signal strength of the response signal And means for emitting the second read signal simultaneously with the first read signal toward the outside of the gate through which the wireless ID tag passes, and response signals from all the wireless ID tags for the second read signal. Means for acquiring ID information; means for determining unnecessary wireless tags based on time-series changes in received signal strength values; and unnecessary wireless tags from the ID information of all received wireless ID tags. And means for performing first filtering for subtracting the ID information based on the response signal for the second read signal from the ID information based on the response signal for the first read signal. It is characterized by.

  The unnecessary wireless tag to be determined is characterized by the fact that the time-series change in the received signal strength value shows a low mountain-like aspect that is less than the reference signal strength value, the one that is almost absent, and the severe one. And

  According to the present invention, reception of unnecessary wireless tag ID information is received as unavoidable, and the configuration is such that ID information of such unnecessary tags is filtered from all received ID information. A first effect is obtained in that ID information can be acquired only from the intended wireless tag without consuming a large amount of resources that are bulky to avoid reception.

  Further, as a result of adopting the above configuration, even if a plurality of wireless ID tags existing within a short distance approach each other and the difference in power value between the response signals is small, the ID is determined from only the intended wireless tag. A second effect that information can be acquired is also obtained.

  Furthermore, as a result of adopting the above configuration, a third effect can be obtained in which even unnecessary wireless tags that exhibit various behaviors such as stopping, turning back, and irregular movement can be eliminated.

  The wireless ID tag system of the present invention acquires ID information from a wireless ID tag that exists in a communication area. For this purpose, a read signal is transmitted toward the communication area, and ID information is acquired from response signals from all wireless ID tags corresponding to the read signal. Then, the desired ID information is obtained by performing filtering that excludes unnecessary ID information of the wireless ID tag from the ID information. Hereinafter, embodiments of the present invention will be described with reference to the drawings.

  FIG. 1 shows a typical scene to which the present invention is applied. An article with a wireless ID tag (hereinafter referred to as a wireless tag) is loaded on a trailer, and ID information is read from the wireless tag by passing through a gate. The read ID information is provided for article storage management. In FIG. 1, only the gate A and the gate B are shown in order to avoid complication of the drawing, but in reality, more gates are usually provided.

  Each gate has the same configuration, in order to read the ID information of the wireless tag, the sensor for detecting the entrance to the gate of the trailer and the exit from the gate, the indicator lamp indicating that it is passing An antenna that radiates a read signal by radio waves and receives a response signal from a wireless tag that passes through the gate is provided. It is desirable to provide a plurality of antennas (four in FIG. 1) in order to improve the reading rate.

  The read signal radiated from the antenna of the gate A should read the ID information from the wireless tag passing through the gate A, and the read signal radiated from the antenna of the gate B should read the ID information from the wireless tag passed through the gate B. is planned. However, the radio wave radiated from the antenna needs to have a certain electric field strength, and when the distance between the gates is short, as shown by a dotted line in the figure, it may reach a neighboring gate area. At this time, if a wireless tag exists in the area of gate B, for example, the response signal of the wireless tag in the area of gate B is received by the antenna of gate A in response to the read signal radiated from the antenna of gate A. There is.

  Moreover, it is scheduled that the read signal radiated from the antenna of each gate should read the ID information of the wireless tag passing through the gate. However, the radio wave radiated from the antenna has swelling in the gate area as indicated by the dotted line in the figure. For this reason, it is possible to read the ID information of the wireless tag that is waiting for passing through the gate or turned back in the middle, and has not yet passed through the gate and is still moving or moving around the gate.

  In the present invention, after accepting the reading of the ID information from the unnecessary tag as described above is unavoidable, only the intended ID information can be obtained by filtering and deleting the ID information from the unnecessary tag. It is something that can be done.

  FIG. 2 shows a basic device configuration example of the wireless ID tag system of the present invention. This wireless ID tag system is for one gate, with the reader / writer control device 10 as the core, an information terminal 20 for taking a human interface, an RFID reader / writer (hereinafter referred to as a reader / writer) 31, An antenna 32 and a sensor 33 are included.

  The reader / writer control device 10 activates the reader / writer 31 when receiving an approach detection signal such as a trailer from the sensor 33. The reader / writer 31 radiates a read signal from the antenna 32 under the control of the reader / writer control device 10, and sends the ID information received from the wireless tag by the antenna 32 to the reader / writer control device 10. The reader / writer control device 10 performs filtering on the ID information.

  FIG. 3 shows functional blocks for the device configuration shown in FIG. Only one sensor 33 is shown. FIG. 3 shows details of the reader / writer control device 10. The main controller 11, information terminal interface unit 12, reader / writer control unit 13, sensor control unit 14, filtering processing unit 15, reader / writer interface unit 16, sensor The interface unit 17, the total data storage unit 18, the individual data storage unit 19, and the reference signal strength storage unit 1 </ b> A are configured.

  The main controller 11 performs overall control of the reader / writer control device 10. The information terminal interface unit 12 is an information terminal 20, the reader / writer interface unit 16 is a reader / writer 311, and the sensor interface unit 17 is an interface with the sensor 33. Take.

  The sensor control unit 14 receives the monitoring signal from the sensor 33 via the sensor interface unit 17, enables the reader / writer control unit 13 (when the sensor is on), and disables the filtering processing unit 15 (when the sensor is off). The reader / writer control unit 13 causes the reader / writer 31 to radiate a read signal from the antenna 32 by a read command via the reader / writer interface unit 16, and the ID received by the antenna 32 from the wireless tag to the reader / writer 31 by a write command. All received data (details will be described later) such as information are written in the all data storage unit 18.

  The filtering processing unit 15 is a core part of the reader / writer control device 10, generates a reader / writer table, an antenna table, and an ID table from data written in the entire data storage unit 18, and stores it in the individual data storage unit 19. Write.

  Here, the reader / writer table is sorted for each reader / writer number among all received data. The antenna table is a table in which all received data are sorted for each reader / writer number and further sorted for each antenna. The ID table is a table in which all received data are sorted for each reader / writer number, further sorted for each antenna, and further sorted for each ID number. And ID information from an unnecessary tag is filtered using these tables. The reference signal strength storage unit 1A stores reference values necessary for the filtering process.

Each of the above-mentioned tables can be understood by referring to a more practical configuration example of the wireless ID tag system whose device configuration is shown in FIG. 4 and functional block diagram 5. This wireless ID tag system is for two gates. Each gate has reader / writers 31 and 41. In order to improve the reading rate, each reader / writer has two in FIG. 4 and four in FIG. Two antennas are connected. The reader / writer table is generated for each of the reader / writers 31 and 41. The antenna table is generated for each antenna 32 of the reader / writer 31 and each antenna 42 of the reader / writer 41. The ID table is generated for each ID number included in each antenna table. The reader / writer control device 10 is not different from that shown in FIGS.
[Example 1]
The filtering process 1 of this embodiment is a response signal from a wireless tag that is waiting to pass through the gate or is turned back in the middle, and has not yet passed through the gate, and is stationary or moving around the gate. The ID information of such unnecessary wireless tag is deleted. Therefore, the received signal strength of the read wireless tag is collected together with the reception time, and the time-series change of the received signal strength value is calculated. From the aspect of the change, the desired wireless tag (target wireless tag) and unnecessary Identify the wireless tag.

  FIG. 6 shows a flowchart of the filtering process 1. Hereinafter, the configuration shown in FIG. 5 will be described as an example. First, when the sensor control unit 14 receives an entry detection signal such as a trailer from one or both of the sensor 33 and the sensor 43 (S1 in FIG. 6), the reader / writer control unit 13 reads by receiving a command from the main controller 11. Sends a command to the reader / writer. The reader / writer transmits a read signal from the antenna (S2 in FIG. 6).

  On the other hand, when the response signal is received from the radio tag of the gate and the ID information is obtained (S3 in FIG. 6), the reader / writer receives the ID information, the received signal strength, and the receiving antenna from the antenna. A number is acquired (S4 in FIG. 6). Then, all the received data (shown in FIG. 7) obtained by adding the reception time and the reader / writer number to these data are sequentially written in the all data storage unit 18 (S5 in FIG. 6). In S2 to S4, the antennas and reader / writers of the two gates function simultaneously.

  As shown in FIG. 8, the filtering processing unit 15 sorts the data written in the entire data storage unit 18 for each reader / writer, each antenna, and each ID information, and performs the above individual data table (reader / writer table, (Antenna table, ID table) are generated and written to the individual data storage unit 19 (S6 in FIG. 6). The reader / writer table refers to all received data in units of reader / writer numbers, the antenna table refers to all received data in units of reader / writer numbers and antenna numbers, and the ID table refers to all received data in units of reader / writer numbers and antennas. The reception time, ID information, and received signal strength are tabulated in number units and ID units.

  FIG. 8 exemplifies table expansion when ID1 and ID2 are both read by the two antennas of the gate A and the two antennas of the gate B. However, there are cases where two antennas of gate A read different ID information such as ID1 and ID2 and two antennas of gate B such as ID3 and ID4. Of course, there may be no response signal.

  Further, FIG. 9 shows table expansion from the entire data table covering all received data to the reader / writer A antenna A1ID1 table of FIG. In the range shown in the drawing, the reader / writer A table is only data related to the reader / writer A in all data tables, the reader / writer A antenna A1 is only data related to the antenna A1 in the reader / writer A table, and the reader / writer A antenna A1ID1 table. It can be seen that only the data relating to ID1 in the reader / writer A antenna A1 table is poured.

  Next, the filtering processing unit 15 calculates a time-series change in the received signal strength value for each ID specified from the reader / writer table, the antenna table, and the ID table from the individual data storage unit 19 (S7 in FIG. 6). ). In this calculation, the inclination is obtained by sequentially calculating the change in the received signal strength value at every reception interval. The above steps S2 to S7 are repeated until the sensor control unit 14 receives an exit detection signal such as a trailer from the sensor 33 or / and the sensor 43 (S8 in FIG. 6).

  When receiving the exit detection signal, the filtering processing unit 15 finally deletes the unnecessary tag using the ID table (S9 in FIG. 6), and ends the filtering processing 1.

  FIG. 10 shows the flow of events in S1 to S9 in time series. In FIG. 10, during the period from sensor ON (S1 in FIG. 6) to sensor OFF (S8 in FIG. 6), data acquisition (S2 to S4 in FIG. 6), acquired data storage (S5 in FIG. 6), individual data extraction (FIG. 6 (S6 in FIG. 6) and calculation (S7 in FIG. 6) are repeated, and finally an event of unnecessary tag deletion (S9 in FIG. 6) is shown.

  Next, an example of unnecessary tag deletion (S9 in FIG. 6) will be described with reference to FIG. FIG. 11 is a graph showing changes in the received electric field strength value obtained by plotting the result of the above calculation for each ID. The filtering processing unit 15 finds a peak in a period from when the sensor is on ((T0-a) in FIG. 11) to when the sensor is off ((T0 + a) in FIG. 11), and based on the number of peaks and the received signal strength E of the peak. Next, it is determined whether an unnecessary tag or a tag that has passed through the gate normally.

  Further, the operation of the filtering processing unit 15 will be described in detail as follows. The inclination k = Δe / Δt is obtained based on the displacement (E2−E1 = Δe) of the received signal strength E at the time T1 and the timing T2 (T2−T1 = Δt) shown in FIG. This slope k is calculated for each time Δt from timing (T0-a) to timing (T0 + a), and is counted as one peak value when the slope k changes from positive to negative. In this way, the number of peaks is counted, and an ID having one peak ((A) and (B) in FIG. 11) is set as a candidate for a wireless tag that has normally passed through the gate.

  Next, assuming that the received signal strength E at the peak of the ID with one peak is a peak value, if this peak value is lower than the reference value ((B) in FIG. 11), the wireless tag normally passes through the gate. Judge that it is not. When a plurality of peaks are counted ((D) in FIG. 11), the wireless tag moves irregularly around the gate, and when peaks are not counted ((C) in FIG. 11), the wireless tag Is stationary and is determined to be an unnecessary tag.

  In the above description, after the number of peaks is counted, the peak value is compared with the reference value. However, after the received signal strength E is compared with the reference value, the unnecessary tag is determined. The number of peaks may be counted.

  The means for obtaining the number of peaks by calculating the slope k has been described above, but the means for obtaining the number of peaks is not limited to such means.

  11 is set in advance in the reference signal strength storage unit 1A in the filing processing unit 15, but a reference tag is set at a predetermined position in the gate and a signal transmitted by the reference tag is received. The received signal strength value may be stored in the reference signal strength storage unit 1A.

  FIG. 12 is a diagram summarizing the filtering process 1 described above, leaving only the wireless tag (A) as a correct reading tag, and the other wireless tags (B), (C) and (D) This indicates that the tag is deleted as an unnecessary tag (S9 in FIG. 6).

Note that the filtering processing unit 15 performs an operation so as to recognize the above-described characteristics of the waveforms A to D based on the change in the received electric field strength. This calculation is performed at the timing (T0) as shown in FIG. The process may be terminated when the feature is recognized without continuing from -a) to the timing (T0 + a).
[Example 2]
The filtering process 2 of this embodiment assumes that the read signal radiated from the antenna reaches the neighboring gate area, and therefore receives the response signal from the wireless tag existing in the neighboring gate area. The ID information of such an unnecessary wireless tag is subtracted from the ID information received in (1). Therefore, an unnecessary tag reading antenna with the back facing the gate area is provided in the neighboring gate area, and the ID information read by the unnecessary tag reading antenna is subtracted from the ID information read by the antenna.

  FIG. 13 shows a gate A having two gate antennas ANT1-1 and ANT1-2 and a gate B having two gate antennas ANT2-1 and ANT2-2 in order to explain the principle of the filtering process 2. Is shown. A gate antenna is synonymous with the antenna described so far, but has been named to distinguish it from an unnecessary tag reading antenna. Here, in order to explain the filtering process 2 while paying attention to the gate A, an unnecessary tag reading antenna ANT1-3 for the gate A is provided between the gate A and the gate B with the back facing the gate A.

  As shown in the figure, the gate antennas ANT1-1 and ANT1-2 radiate transmission signals in the right direction and left direction, respectively. Similarly, the gate antennas ANT2-1 and ANT2-2 are not shown, The transmission signal is emitted in the right and left directions. Further, a transmission signal is radiated from the unnecessary tag reading antennas ANT1-3 toward the gate B in the right direction. The unnecessary tag reading antennas ANT1-3 are directed rightward from the gate B and do not communicate with the wireless tags in the gate A.

  The transmission signal radiated from the gate antenna ANT1-1 extends to the area of the gate B, and the ID information can be read from the wireless tag b existing in the area of the gate B in addition to the wireless tag a passing through the gate A. is there. At this time, the unnecessary tag reading antenna ANT1-3 reads the ID information from the wireless tag b. FIG. 14 briefly shows this state. Therefore, by subtracting the ID information of the wireless tag b read by the unnecessary tag reading antenna ANT1-3 from the ID information of the wireless tag a and the ID information of the wireless tag b read by the gate antenna ANT1-1, the gate antenna ANT1- 1 correctly reads only the ID information of the wireless tag a as a result.

  The configuration for performing the filtering process 2 may be basically the same as the configuration shown in FIGS. 1 to 5, but an unnecessary tag reading antenna needs to be added. Such a configuration change method will be apparent from FIG. Also, as shown in FIGS. 1, 4 and 5, in many cases there are multiple gate antennas per gate to improve the reading rate, one of those overlapping gate antennas, eg, It is also possible to divert the thirteen gate antennas ANT2-1 to unnecessary tag reading antennas. In this case, the unnecessary tag reading antenna ANT1-3 becomes “unnecessary”.

  In the filtering process 2, the data flowing from the reader / writers 31 and 41 to the reader / writer control apparatus 10 includes the ID information, the reception time, the reception antenna number, and the reader / writer among the data in the filtering process 1 shown in FIG. A number is sufficient, and such data is written in the entire data storage unit 18.

  FIG. 15 shows a flowchart of the filtering process 2. First, when the sensor control unit 14 receives an entry detection signal such as a trailer from one or both of the sensor 33 and the sensor 43 (T1 in FIG. 15), the reader / writer control unit 13 sends a reading command to the reader / writer. The reader / writer transmits a read signal from the antenna (T2 in FIG. 15).

  On the other hand, when the response signal is received from the radio tag of the gate and the ID information is obtained (T3 in FIG. 15), the reader / writer acquires the ID information and the receiving antenna number from the antenna. (T4 in FIG. 15). Then, data obtained by adding a reader / writer number to these data is sequentially written in all data storage unit 18 (T5 in FIG. 15). In T2 to T4, the antennas and reader / writers of the two gates function simultaneously.

  The above data acquisition (T2 to T4 in FIG. 15) and acquisition data storage (T5 in FIG. 15) are repeatedly performed until the sensor control unit 14 receives an exit detection signal such as a trailer from the sensor 33 or / and the sensor 43 (FIG. 15). T6).

  Upon receiving the exit detection signal, the filtering processing unit 15 sorts the data written in the entire data storage unit 18 for each reader / writer and each antenna to generate an individual data table (reader / writer table, antenna table). The data is written into the individual data storage unit 19 (T7 in FIG. 15). The reader / writer table is a reader / writer unit, the antenna table is a reader / writer unit, and ID information is tabulated in antenna units.

  Finally, the filtering processing unit 15 subtracts the ID information of the unnecessary tag reading antenna corresponding to the gate antenna from the ID information in the gate antenna specified by the reader / writer table and the antenna table (T8 in FIG. 15). Which antenna is the unnecessary tag reading antenna for the gate antenna is set in advance so that the filtering processing unit 15 can recognize it.

  FIG. 16 shows the event flow in the filtering process 2 in time series. In FIG. 16, data acquisition (T2 to T4 in FIG. 15) and all data storage (T5 in FIG. 15) are repeated from sensor on (T1 in FIG. 15) to sensor off (T6 in FIG. 15), and finally the table Events of extraction (T7 in FIG. 15) and unnecessary tag deletion (T8 in FIG. 15) are shown. In the event flow shown in FIG. 10, it is not necessary to extract and calculate individual data.

FIG. 17 summarizes the filtering process 2. For example, when attention is paid to the gate A, the antenna of the gate B facing away from the reading tag of the gate A or the unnecessary tag reading antenna. It shows that the reading tag is subtracted.
[Example 3]
The filtering process 3 of this embodiment is intended to perform a more accurate filtering process by executing both the filtering process 1 and the filtering process 2 and enjoying the characteristics of both filtering processes at the same time.

  In this case, the filtering process 1 uses the reader / writer A / antenna A1 / ID table of FIG. 9, and the filtering process 2 uses the reader / writer A / antenna A1 table of FIG.

  All the filtering processes described above can be performed by a computer program executed by a CPU constituting the reader / writer control device. These contents can be read from the description given so far, particularly with reference to FIGS. 6, 10, 12, 15, 16 and 17.

  The present invention can be used for article entry / exit management, person entry / exit management, vehicle entry / exit management, and the like.

The figure which shows one typical scene where this invention is applied The figure which shows the basic apparatus structural example of the radio | wireless ID tag system of this invention Basic block diagram of the wireless ID tag system of the present invention The figure which shows the more realistic apparatus structural example of the radio | wireless ID tag system of this invention More realistic block diagram of the wireless ID tag system of the present invention Flowchart of filtering process 1 in the present invention The figure which shows the structure of the data memorize | stored in all the data storage parts in this invention The figure which shows the table expansion | deployment in this invention The figure which shows the table expansion | deployment in this invention with the example of a registration content Time chart of filtering process 1 The figure which shows the received electric field strength change model in the filtering process 1 Diagram summarizing filtering process 1 The figure for demonstrating the principle of the filtering process 2 in this invention Supplementary explanatory diagram of filtering process 2 Flowchart of filtering process 2 in the present invention Time chart of filtering process 2 Diagram summarizing filtering process 2

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Reader / writer control apparatus 11 Main controller 12 Information terminal interface part 13 Reader / writer control part 14 Sensor control part 15 Filtering process part 16 Reader / writer interface part 17 Sensor interface part 18 All data storage part 19 Individual data storage part 1A Reference signal intensity value Storage unit 20 Information terminal 30 Gate A component device 31 Reader / writer 32 Antenna 33 Sensor 34 Wireless tag 40 Gate B component device 41 Reader / writer 42 Antenna 43 Sensor 44 Wireless tag

Claims (3)

  In a wireless ID tag system that acquires ID information from a wireless ID tag that passes through a gate;
  Means for emitting a read signal when the wireless ID tag enters the gate;
  Means for receiving response signals from all the wireless ID tags in response to the read signal to obtain ID information;
  Means for obtaining a received signal strength of the response signal;
  Means for determining a wireless ID tag other than a wireless ID tag having a peak value equal to or higher than a predetermined value of the received signal intensity within a predetermined time as an unnecessary wireless ID tag;
  A wireless ID tag system comprising filtering means for deleting the ID information of the unnecessary wireless ID tag from the ID information of all the wireless ID tags that have received the response signal.   In a wireless ID tag reader / writer control device that acquires ID information from a wireless ID tag that passes through a gate;
  Means for instructing the wireless ID tag reader / writer installed at the gate to emit a read signal when the wireless ID tag enters the gate;
  Means for receiving response signals from all the wireless ID tags in response to the read signal to obtain ID information;
  Means for obtaining a received signal strength of the response signal;
  Means for determining a wireless ID tag other than a wireless ID tag having a peak value equal to or higher than a predetermined value of the received signal intensity within a predetermined time as an unnecessary wireless ID tag;
  An apparatus for controlling a wireless ID tag reader / writer, comprising means for performing filtering for deleting the ID information of the unnecessary wireless ID tag from the received ID information of all the wireless ID tags.   Executed by the CPU of the wireless ID tag system that obtains ID information from the wireless ID tag passing through the gate;
  In response to the gate, emitting a read signal when the wireless ID tag enters the gate;
  Receiving response signals from all the wireless ID tags for the read signal to obtain ID information;
  Obtaining a received signal strength of the response signal;
  A step of determining a wireless ID tag other than a wireless ID tag having a peak value equal to or higher than a predetermined value of the received signal intensity as a unnecessary wireless ID tag within a predetermined time;
  A program comprising a step of performing filtering to delete the ID information of the unnecessary wireless ID tag from the received ID information of all the wireless ID tags.

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