JP2011001132A - Radio id tag system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To overcome a problem that determination of a passing order of a gate becomes difficult when a plurality of radio ID tags approach.SOLUTION: The radio ID tag system includes, with respect to each gate, a means for emitting an inquiry signal when the radio ID tag 34 enters within the gate; a means for obtaining ID information upon receiving a response signal from the radio ID tag relative to the inquiry signal; and a means for obtaining receiving electric power of the response signal. Further, the system includes a means for determining the unnecessary radio tag by a change with time of the receiving electric power; a means for performing filtering that the ID information of the unnecessary radio ID tag is deleted from the ID information of the received radio ID tag; and a means for determining the order of the radio ID tags passed through the gate in every gate by a change with the time of a receiving signal intensity value relative to the plurality of radio ID tags passed through the gate in every gate.

Description

  The present invention relates to a wireless ID (Identification) tag system, and in particular, wireless information for acquiring ID information from a predetermined wireless ID tag that has passed through a communication area and accurately determining the order in which the wireless ID tag has passed through the communication area. The present invention relates to an ID tag system and a wireless ID tag passage order determination method.

  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 a gate composed of an RFID reader / writer device, an RFID antenna, a gate structure, and the like for attaching an RFID (Radio Frequency Identification) tag to an article or the like to be managed and reading the ID information of the RFID tag. When reading the ID information at the gate, the reading range is adjusted by changing the transmission power value of the signal transmitted from the RFID reader / writer device. The second adjusts the reading range by changing the directivity by adjusting the antenna mounting angle of the gate for each installation location, and the third adjusts the reading range using a radio wave absorber or a radio wave reflector.

  Using this technology, 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 order of passage is grasped by allowing the articles to pass through the gate with a sufficient interval between the articles to the extent that they do not (none of the above is related to the literature known invention).

  However, in the technique of adjusting the reading range by changing the transmission power value so as not to read the RIFD tag outside the gate, the radio wave in the gate is weakened, so that the originally required reading rate in the gate is deteriorated. Furthermore, there is a problem that it is difficult to cope with high-speed reading with a gate on a conveyor, for example.

  In addition, the technique of adjusting the antenna angle for each installation location so as not to read the RIFD tag outside the gate requires a great amount of adjustment time, and the adjustment is made so that unnecessary tags are not read, thereby deviating from the optimum antenna angle. Therefore, the reading rate is deteriorated.

  Further, in the technology using a radio wave absorber or a radio wave reflector so as not to read the RIFD tag outside the gate, the apparatus becomes large and a large installation space is required. In addition, for example, at the distribution site, it may be difficult to secure a line of sight by installing a radio wave absorber or a radio wave reflector, which reduces the safety of the work site and misreads articles before and after the gate in the gate. There is a problem that the number of readings per unit time is reduced and work efficiency is deteriorated because the intervals between articles need to be sufficiently separated so as not to take them.

  In order to eliminate these problems, the present applicant receives ID information of unnecessary wireless ID tags as unavoidable, and filters ID information of unnecessary tags from all received ID information. Previously, a wireless ID tag system adopting the above was proposed (Japanese Patent Application 2008-126511). In this proposal, a method for detecting a peak value of received signal strength is disclosed in order to determine a wireless ID tag that has normally passed through a gate, and the reception time of the wireless ID tag is written in a data storage unit.

  By the way, there is a scene in which the order of receiving the desired ID information is not limited to eliminating ID information of unnecessary tags. For example, it is a case where it is desired to increase the accuracy in sorting the package or article with the wireless ID tag attached to each delivery destination. As a conventional technique of this type, a wireless ID tag is based on a time-series identification result indicating that a reader / writer reads data recorded in a received wireless ID tag and that the data can be read normally. It is known to specify the timing at which has passed a predetermined position.

  However, in this technique, whether or not the wireless ID tag is identified is converted into binary information, and the identification result (identification success / failure) is leveled from the time-series data of the binary information according to a rule based on the continuity of the same identification result. Since the conversion tag identification success / failure pattern is converted into an evaluation value of the reception timing, and the timing at which the evaluation value is the maximum is the passage time of the wireless ID tag, there is a limit to the determination accuracy of the passage order.

Japanese Patent Application No. 2008-126511
JP 2006-297172 A

  The problem to be solved is that the determination accuracy of the communication area passing order of the wireless ID tag cannot be increased.

  The main feature of the present invention is to compare the peak values of received signal strengths in time series in order to correctly determine the communication area passing order of wireless ID tags.

  In the wireless ID tag system of the present invention, the order of passage of wireless ID tags through a communication area is determined based on a time-series comparison of peak values of received signal strength, so that a plurality of received wireless ID tags communicate continuously. When passing through an area, even if the interval between wireless ID tags is not sufficient, the order of passage can be determined with high accuracy, so the number of readings per unit time can be increased and work efficiency can be improved. There is an advantage that you can.

The figure which shows one typical scene where this invention is applied The figure which shows the typical other 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 processing 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 The figure which shows the received electric field strength change model in filtering processing Conceptual diagram showing the relationship between received signal strength and approximate curve function Overview of filtering process Flowchart of wireless ID tag gate passage order determination processing in the present invention The figure which illustrates the generation history of the data table which a tag passage order judgment part generates Tag passage order judgment processing time chart The figure which showed the change of the reception electric field strength value of the plural tags which move on the conveyor Summarized the wireless ID tag gate passage order determination process

  The purpose of determining the wireless ID tag communication area passing order with high accuracy is realized by chronological comparison of peak values of received signal strength after deleting unnecessary ID information of the wireless ID tag.

  1 and 2 show typical scenes to which the present invention is applied. In FIG. 1, a gate is installed in each of two adjacent passages, an article with a wireless ID tag attached is loaded on a cart, and the antenna installed on the gate is wireless ID by passing through the gate continuously. Communication with the tag is performed, and the ID information of the wireless ID tag is read.

  In FIG. 2, a gate is installed on the conveyor, and a plurality of articles with wireless ID tags are continuously moved adjacently on the conveyor and pass through the gate installed on the conveyor, thereby being installed on the gate. The antenna communicates with the wireless ID tag, and the ID information of the wireless ID tag is read. The read ID information is provided for article storage management.

  In order to avoid complication of the drawing, only gate A and gate B are shown in FIG. 1 and only a single gate is shown in FIG. 2, but in practice, more gates are usually provided and the present invention is implemented. The embodiment is not limited to the form shown in FIGS.

  Each gate has the same configuration, a sensor for detecting entry into and exit from the gate, passage through the gate, emission of radio waves, and ID information of the wireless ID tag. An indicator lamp for displaying the reading status, an RFID antenna that radiates an inquiry signal by radio waves to read ID information of the wireless ID tag, and receives a response signal from the wireless ID tag that passes through the gate, and an RFID reader / It has a writer. In order to improve the reading rate, it is desirable to provide a plurality of antennas per gate (four in FIG. 1 and three in FIG. 2). The radio wave radiation direction of the antenna is directed to the passage where the carriage moves and the conveyor where the article moves.

  The general gate configuration has been described above, but the configuration is not limited to the above as long as it has a function of acquiring ID information when passing through a wireless ID tag. For example, one antenna may be installed for one gate.

  In FIG. 1, the antenna of gate A radiates an inquiry signal to the wireless ID tag passing through gate A, reads ID information as a response signal, and the antenna of gate B makes an inquiry to the wireless ID tag passing through gate B. It is scheduled to emit a signal and read the ID information as its response signal. However, the radio wave radiated from the antenna must have a certain electric field strength to supply power to the tag. When the distance between the gates is short, as shown by the dotted line in the figure, the neighboring gates Can span an area. At this time, if a wireless ID tag exists in the area of gate B, for example, a response signal of the wireless ID tag in the area of gate B is received by the antenna of gate A in response to an inquiry signal radiated from the antenna of gate A. There are things to do.

  Further, it is scheduled that the antenna of each gate should emit an inquiry signal to the wireless ID tag passing through the gate and read the ID information as a response signal. 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, there are wireless ID tags that are waiting to pass through the gate or are turned back in the middle, and have not yet passed through the gate and are still moving around the gate, or a plurality of wireless ID tags in succession. When passing through the gate, the ID information of the wireless ID tag before and after the traveling direction may be read.

  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. In addition, the order of passage of the plurality of wireless ID tags that have passed through the gate is determined with high accuracy.

  FIG. 3 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 and has a reader / writer control device 10 as a 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 entry detection signal of an article or the like from the sensor 33. The reader / writer 31 radiates an inquiry signal repeatedly from the antenna 32 at a constant period under the control of the reader / writer control device 10, and the antenna 32 receives a response signal from the wireless ID tag. The reader / writer 31 acquires ID information and the received signal strength of the response signal from the response signal, and sends them to the reader / writer control device 10 together with the response signal reception time. The reader / writer control device 10 performs filtering on the ID information.

  In addition, at the gate on the conveyor, a plurality of articles pass through the gate continuously, but by repeating the same reading operation for the radio ID tag of each article, the ID of the radio ID tag for the plurality of articles Get information. The reader / writer control device 10 performs a filtering process on the ID information and performs a gate passage order determination process for each wireless ID tag.

  FIG. 4 shows functional blocks for the device configuration shown in FIG. FIG. 4 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 all data storage unit 18, the individual data storage unit 19, the reference signal strength storage unit 1A, the tag passage order determination unit 1B, and the tag passage order storage unit 1C 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 31, and the sensor interface unit 17 is an interface with the sensor 33. Take.

  The sensor control unit 14 receives a monitoring signal from the sensor 33 via the sensor interface unit 17, and when the sensor is turned on, the main controller 11 enables the filtering processing unit 15 and the tag passage order determination unit 1B, and further causes the reader / writer control unit 13 to operate. The reader / writer 31 is enabled. When the sensor is off, the main controller 11 disables the filtering processing unit 15 and the tag passage order determination unit 1B, and further disables the reader / writer 31 via the reader / writer control unit 13.

  The reader / writer control unit 13 causes the reader / writer 31 to repeatedly radiate an inquiry signal from the antenna 32 at a constant period by a reading command via the reader / writer interface unit 16, and the antenna 32 is connected to the main controller 11 by the wireless ID by a writing command. All received data (details will be shown later) such as ID information received from the tag are written in the all data storage unit 18.

  The filtering processing unit 15 generates a reader / writer table, an antenna table, and an ID table from the data written in the entire data storage unit 18 and writes it in the individual data storage unit 19. Further, the filtering processing unit 15 refers to each table written in the individual data storage unit 19, determines an unnecessary tag from the time-series change in received signal strength, and deletes it from the individual data storage unit 19.

  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. The filtering processing unit 15 filters ID information from unnecessary tags 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 FIGS. 5 and 6 showing a more realistic configuration example of the wireless ID tag system. FIG. 5 shows a device configuration, and FIG. 6 shows a functional block. This wireless ID tag system is for two gates. Each gate is provided with reader / writers 31 and 41. In order to improve the reading rate, each reader / writer has four in FIG. 5 and two 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.

  The tag passage order determination unit 1B extracts the peak points from the unnecessary tag deleted data written in the individual data storage unit 19, and compares the peak points in time series, thereby obtaining the desired wireless ID tag. The gate passage order is determined, and the determination result is written in the tag passage order storage unit 1C. Here, the peak point refers to the time when the maximum peak value is given on the time-series change curve of the received signal strength for each wireless ID tag.

  The determination processing in this embodiment is a response signal from a wireless ID 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 still moving or moving around the gate. In this case, the ID information of such unnecessary wireless ID tags is deleted, and the passing order of the wireless ID tags that correctly pass through the gate is accurately determined. Therefore, the received signal strength of the read wireless ID tag is sampled together with the reception time to calculate a time-series change in the received signal strength, and the expected wireless ID tag (target wireless ID tag) and By identifying the unnecessary wireless ID tag and extracting the peak point of the time-series change curve of the received signal strength of the intended wireless ID tag, the passing order of the intended wireless ID tag that has passed through the gate can be determined. Determine.

  FIG. 7 shows a flowchart of the filtering process. Hereinafter, the configuration shown in FIG. 6 will be described as an example. First, when the sensor control unit 14 receives an approach detection signal such as a carriage from one or both of the sensor 33 and the sensor 43 (S1 in FIG. 7), the reader / writer control unit 13 reads in response to a command from the main controller 11. Sends a command to the reader / writer. The reader / writer causes the inquiry signal to be repeatedly transmitted from the antenna at regular intervals (S2 in FIG. 7).

  When the response signal is repeatedly received from the radio ID tag of the gate in response to the inquiry signal transmitted repeatedly at a fixed period (S3 in FIG. 7), the reader / writer receives the ID information and the response signal from the response signal. The signal strength and the antenna number that received the response signal are acquired (S4 in FIG. 7). Then, all the received data (shown in FIG. 8) 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. 7). In S2 to S4, the antennas and reader / writers of the two gates function simultaneously.

  As shown in FIG. 9, 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 individual data table (reader / writer table, (Antenna table, ID table) is generated and written to the individual data storage unit 19 (S6 in FIG. 7). 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. 9 exemplifies table development when the two antennas of the gate A and the two antennas of the gate B similarly read ID1 and ID2. However, there are cases where the two antennas of gate A read different ID information such as ID1 and ID2 and the two antennas of gate B ID3 and ID4, and there is no wireless ID tag that enters one gate. Of course, there may be no response signal from the antenna.

  FIG. 10 shows table expansion from the entire data table covering all received data to the reader / writer 31 / antenna 32A / ID1 table of FIG. In the range shown in the figure, the reader / writer 31 table only includes data related to the reader / writer 31 in all data tables, and the reader / writer 31 / antenna 32A includes only data related to the antenna 32A in the reader / writer 31 table, and the reader / writer 31 / antenna. It can be seen that the 32A / ID1 table is obtained by sorting only data related to ID1 in the reader / writer 31 antenna 32A table.

  Next, the filtering processing unit 15 calculates a time-series change in received signal strength 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. 7). . In this calculation, a change in received signal strength is sequentially calculated at intervals of a reception interval to obtain a slope. The above steps S2 to S7 are repeated until the sensor control unit 14 receives an exit detection signal from the sensor 33 or / and the sensor 43 (S8 in FIG. 7).

  When receiving the exit detection signal, the filtering processing unit 15 finally deletes the ID information of the unnecessary tag using the ID table (S9 in FIG. 7), and ends the filtering process.

  FIG. 11 shows the flow of events in S1 to S9 in time series. In FIG. 11, data acquisition (S2 to S4 in FIG. 7), acquired data storage (S5 in FIG. 7), individual data extraction (FIG. 7) from sensor on (S1 in FIG. 7) to sensor off (S8 in FIG. 7). 7 (S6) and calculation (S7 in FIG. 7) are repeated, and finally an event of unnecessary tag deletion (S9 in FIG. 7) is shown.

  Next, an example of unnecessary tag deletion (S9 in FIG. 7) will be described with reference to FIG. FIG. 12 is a graph showing changes in received electric field strength obtained by plotting the above calculation results for each ID. The filtering processing unit 15 finds a peak in a period from when the sensor is on ((T0-a) in FIG. 12) to when the sensor is off ((T0 + a) in FIG. 12), and based on the number of peaks and the received signal strength E of the peak. It is determined whether it is an unnecessary tag or a tag that has passed 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 time 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 with one peak ((A) and (B) in FIG. 12) is a candidate for a wireless ID tag that has passed through the gate normally.

  Next, assuming that the received signal strength E at the peak of the ID having one peak is a peak value, when this peak value is lower than the reference value ((B) in FIG. 12), the wireless ID tag is normally gated. Judge that it has not passed. When a plurality of peaks are counted ((D) in FIG. 12), the wireless ID tag moves irregularly around the gate, and when peaks are not counted ((C) in FIG. 12), The ID 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 method for obtaining the peak point by calculating the slope k has been described above. However, the method is not limited to such a method, and for example, a known least square method may be employed. In this case, a curve expressed by a function that minimizes the sum of squares of differences between all received signal strengths E and function values is used as an approximate curve, and the peak point is calculated. FIG. 13 is a conceptual diagram showing the relationship between the received signal strength E and the approximate curve function y = f (x), and the received signal strength E is plotted.

  The reference value in FIG. 12 is set in advance in the reference signal strength storage unit 1A in the filtering processing unit 15. However, 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. 14 is a diagram summarizing the filtering processing described above, leaving only the wireless ID tag of (A) as a correct reading tag, and other wireless ID tags of (B), (C), and (D). Indicates deletion as an unnecessary tag (S9 in FIG. 7).

  Note that the filtering processing unit 15 performs an operation so that the above-described characteristics of the waveforms A to D can be recognized 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).

  The tag passage order determination unit 1B extracts the peak points of each tag from the change curve of the received signal strength value of the tag that has passed through the gate, which is the result of the filtering process executed by the filtering processing unit 15, and extracts them as time. By comparing in series, the gate passage order is determined for tags that have passed through the gate. The determination result is written in the tag passage order storage unit 1C.

  FIG. 15 shows a flowchart of the tag passage order determination process. Hereinafter, the configuration shown in FIG. 4 will be described as an example. The tag passage order determination process takes over the filtering process described above with reference to FIG. In S1 to S9 of FIG. 7, unnecessary tag ID information is deleted for one wireless ID tag, but this process (U1 of FIG. 15) is performed for all wireless ID tags (U2 of FIG. 15).

  Then, the tag passage order determination unit 1B uses the ID table from which the ID information of the unnecessary tags is deleted to obtain the peak point for each wireless ID tag as described above (U3 in FIG. 15). The data table which extracted the data which concerns from each ID table is produced | generated, and it writes in the separate data memory | storage part 19 (U4 of FIG. 15).

  FIG. 16 is a specific example showing how the data table is generated. FIG. 16A shows a concatenation of ID tables of tag ID1 to tag ID4. The tag passage order determination unit 1B, for example, receives the reception time 0′01 of the received signal strength −55 for the tag ID1. '24 is the peak point. Similarly, for tag ID2 to tag ID4, data related to the peak point is extracted from each ID table, and a data table shown in FIG. 16B is generated.

  The tag passage order determination unit 1B compares the reception times in each data of the data table in time series, and determines the gate passage order for tags that have passed through the gate (U5 in FIG. 15). In the example of FIG. 16, it can be seen from the reception time that the wireless ID tags pass in the order of ID numbers. Finally, the tag passage order determination unit 1B writes the determination result in the tag passage order storage unit 1C (U6 in FIG. 15).

  FIG. 17 shows the flow of events in U1 to U6 of FIG. 15 in time series. The sensor-on to sensor-off and unnecessary tag deletion in FIG. 17 correspond to U1 in FIG. 15, and are repeated for all tags detected by the antenna 32 (U2 in FIG. 15). After that, the peak point extraction on the received signal strength change curve of each tag (U3 in FIG. 15), the order determination of the gate passage (U5 in FIG. 15), and finally the determination result storage (U6 in FIG. 15) It has become.

  Next, an example of determination of the gate passage order (U5 in FIG. 15) will be described with reference to FIG. FIG. 18 shows the result of the above calculation for each ID when tag a, tag b, tag c, and tag d continuously move on the conveyor and pass through the gate in the order of a, b, c, and d. It is the graph which showed the change of the received electric field strength value obtained by plotting about four tags from tag a to tag d.

  The tag passage order determination unit 1B finds the peak point of each tag during the period from the sensor ON of the tag a to the sensor OFF of the tag d, and compares each of them in time series to determine in which order the gates have passed. Do. When the received signal strength change curve draws a substantially semi-circular shape or a triangular shape and the number of peak points is one and the received signal strength exceeds a predetermined reference value, the wireless ID tag is gated. Is determined to have passed. Further, the peak points of the change curve of the received signal strength of the wireless ID tag determined to have passed through the gate are compared, and the order (early order) of the peak points with respect to the time is defined as the order in which the wireless ID tag has passed through the gate. In the example of FIG. 18, it can be seen that the gates are passed in the order of tag a → tag b → tag c → tag d.

  FIG. 19 is a diagram summarizing the tag passage order determination described above, leaving only the wireless ID tag of determination (A) as a correct reading tag, and other determinations (B), (C), and (D). This shows that the wireless ID tag is deleted as an unnecessary tag (S9 in FIG. 7), and then the gate passing order is determined for the wireless ID tag satisfying the determination (A).

  The determination process described above can be performed by a computer program executed by a CPU constituting the reader / writer control device. The contents can be read from the description given so far, in particular with reference to FIGS. 7, 15, 16 and 19. FIG.

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

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 1B Tag passage order determination unit 1C Tag passage order storage unit 20 Information terminal 30 Gate component device 31 Reader / writer 32 Antenna 33 Sensor 34 Wireless ID tag 40 Gate component device 41 Reader / writer 42 Antenna 43 Sensor 44 Wireless ID tag

Claims (19)

Means for emitting an inquiry signal toward the communication area;
Means for receiving a response signal from the wireless ID tag in response to the inquiry signal and acquiring ID information;
Means for obtaining a received signal strength of the response signal;
Unnecessary wireless ID tag determination means for determining an unnecessary wireless ID tag by a time-series change in the received signal strength;
A passing wireless ID tag selection means for selecting a wireless ID tag that has passed through the communication area by deleting ID information of the unnecessary wireless ID tag from the acquired ID information;
Means for acquiring each peak point from a time-series change in the received signal strength of the passing radio ID tag;
Wireless ID tag passage order determination means for determining the passage order of the passage wireless ID tags by time-series comparison of the peak points of the passage wireless ID tags;
A wireless ID tag system comprising:   When the received signal strength change curve draws a substantially semicircular or a substantially triangular shape and the number of peak points is one and the received signal strength exceeds a predetermined reference value, the wireless ID tag The wireless ID tag system according to claim 1, wherein it is determined that has passed through the communication area. The interrogation signal is radiated and the response signal is received through at least one antenna at regular intervals, the ID information and the received signal strength of the response signal are acquired from the response signal, and the response signal is received along with the reception time of the response signal. A reader / writer for sending to the writer control device is provided for the communication area,
The reader / writer control device controls at least one of the reader / writers to determine the unnecessary wireless ID tag, to select a wireless ID tag that has passed through the communication area, to acquire the peak point, and to determine the passage order. The wireless ID tag system according to claim 1 or 2, wherein:   The pass order is determined by sorting all received response signals for each reader / writer number, further sorting for each antenna, further sorting for each ID number, and an ID table from which unnecessary tag ID information has been deleted. Use to obtain the peak point for each wireless ID tag, generate a data table in which data relating to the peak point is extracted from each ID table, and compare the reception time in each data of the data table in time series 4. The wireless ID tag system according to claim 3, wherein the wireless ID tag system is adapted for the reader / writer.   The peak point is obtained as a peak when the slope of the displacement of the received signal intensity changes between adjacent timings of the fixed period from positive to negative. The wireless ID tag system described.   5. The wireless ID tag system according to claim 3, wherein the peak point is obtained by applying a least square method to the received signal intensity of the fixed period.   The wireless ID tag system according to claim 1, wherein the communication area is defined to correspond to at least one gate.   The wireless ID tag system according to claim 1, wherein the communication area is defined for at least one conveyor. A procedure for emitting an inquiry signal toward the communication area;
A procedure of receiving a response signal from the wireless ID tag in response to the inquiry signal and acquiring ID information;
Obtaining a received signal strength of the response signal;
A procedure for determining an unnecessary wireless ID tag based on a time-series change in the received signal strength;
A procedure for selecting a wireless ID tag that has passed through the communication area by deleting ID information of the unnecessary wireless ID tag from the acquired ID information;
Obtaining each peak point from a time-series change in the received signal strength of the passing radio ID tag;
A procedure for determining a passing order of the passing wireless ID tags by time-series comparison of peak points of the passing wireless ID tags;
A wireless ID tag passage order determination method, comprising:   When the received signal strength change curve draws a substantially semicircular or a substantially triangular shape and the number of peak points is one and the received signal strength exceeds a predetermined reference value, the wireless ID tag The wireless ID tag passage order determination method according to claim 9, wherein it is determined that has passed through the communication area. A step of repeating the emission of the interrogation signal and the reception of the response signal at regular intervals via at least one antenna;
The radio according to claim 9 or 10, further comprising: a procedure for acquiring the ID information and the received signal strength of the response signal from the response signal and acquiring the reception time of the response signal for the communication area. ID tag passage order determination method. The determination of the passing order is performed for each reader / writer number having the procedure according to claim 11.
Sorting all received response signals, further sorting for each antenna, and further sorting by ID number to generate an ID table;
A procedure of deleting ID information of unnecessary tags from the ID table;
A procedure for obtaining the peak point for each wireless ID tag using an ID table in which the ID information of the unnecessary tag is deleted;
A procedure for generating a data table obtained by extracting data relating to the peak point from each ID table;
A procedure for comparing the reception time in each data of the data table in time series,
The wireless ID tag passage order determination method according to claim 11, wherein the wireless ID tag passage order determination method is performed for the reader / writer.   13. The peak point is obtained as a peak when an inclination of a displacement of the received signal intensity between adjacent timings of the certain period changes from positive to negative. The wireless ID tag passage order determination method described.   13. The wireless ID tag passage order determination method according to claim 11, wherein the peak point is obtained by applying a least square method to the received signal intensity of the fixed period. It is executed by the CPU of the wireless ID tag system that radiates an inquiry signal toward the communication area, receives a response signal from the wireless ID tag with respect to the inquiry signal, and acquires ID information and the received signal strength of the response signal.
Determining an unnecessary wireless ID tag by a time-series change in the received signal strength;
Selecting a wireless ID tag that has passed through the communication area by deleting ID information of the unnecessary wireless ID tag from the acquired ID information;
Obtaining each peak point from a time-series change in the received signal strength of the passing radio ID tag;
Determining a passing order of the passing radio ID tags by time-series comparison of peak points of the passing radio ID tags;
The program characterized by having.   When the received signal strength change curve draws a substantially semicircular or a substantially triangular shape and the number of peak points is one and the received signal strength exceeds a predetermined reference value, the wireless ID tag The program according to claim 15, wherein it is determined that has passed through the communication area. The determination of the passing order is performed by repeating the emission of the inquiry signal and the reception of the response signal at a constant cycle via at least one antenna, and obtaining the ID information and the received signal strength of the response signal from the response signal. For each reader / writer number that obtains the response signal reception time,
Sorting all received response signals, sorting by antenna, and sorting by ID number to generate an ID table;
Deleting ID information of unnecessary tags from the ID table;
Using the ID table from which the ID information of the unnecessary tag is deleted, obtaining the peak point for each wireless ID tag;
Generating a data table obtained by extracting data relating to the peak point from each ID table;
Comparing the reception time in each data of the data table in time series;
The program according to claim 15, wherein the program is executed in correspondence with the reader / writer.   18. The program according to claim 17, wherein the peak point is obtained as a peak when an inclination of a displacement of the received signal intensity between adjacent timings of the certain period changes from positive to negative.   The program according to claim 17, wherein the peak point is obtained by applying a least square method to the received signal intensity of the fixed period.

Images