JP2013058055A - Rfid system and moving direction discrimination method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an RFID system capable of accurately determining the moving direction of an IC tag without using any special sensor and a moving direction determination method.SOLUTION: The RFID system is configured of: arithmetic means for receiving the reading signal level or reading frequency of a first antenna 6 and a second antenna 7, and for subtracting the reading signal level or reading frequency of the second antenna 7 from the reading signal level or reading frequency of the first antenna 6 at the same reading time to successively calculate a difference, and for cumulatively adding the differences, and for further cumulatively adding the cumulatively added values to calculate a final value; and determination means for determining the moving direction of an IC tag 9 on the basis of the final value.

Description

  The present invention relates to an RFID system and a moving direction determining method for determining a moving direction of an IC tag.

  An RFID (Radio Frequency IDentification) reader that communicates identification information and the like with an IC tag is connected to an antenna for wireless communication, and communication with the IC tag is performed by the radio wave transmitted from the antenna. It is carried out. An RFID system in which this RFID reader is incorporated in a gate of a building or the like is used for entrance / exit management of a person who has an IC tag, carry-in / out management of a baggage attached with an IC tag, and the like.

  In such an RFID system, in addition to reading the identification information of the IC tag and managing entry / exit, etc., it is also important to determine the direction of movement of the IC tag in the gate, that is, management of information such as entry / exit. .

  In the conventional RFID system, in order to determine the movement direction of the IC tag, a method is proposed in which a plurality of detection sensors using infrared rays or the like are arranged along the movement path in the gate and the movement direction is determined from the detection order of each sensor. Has been. FIG. 7 is a block diagram illustrating a moving direction determination method using a conventional RFID system.

  In FIG. 7, a first detection sensor 21 and a second detection sensor 22 are arranged along a movement path in a gate through which an IC tag 19 attached to a person or a baggage passes. An RFID reader 11 is incorporated in the gate, and the RFID reader 11 is provided with an antenna 18 for performing wireless communication for reading identification information of the IC tag 19.

  When the RFID reader 11 communicates with the IC tag 19, the logic circuit 13 encodes and decodes the transmission / reception signal according to the instruction of the control circuit 12, the analog signal is amplified and transmission / reception separated by the high frequency analog circuit 14, The antenna switch circuit 15 switches between operation and non-operation of the antenna 18, and when the antenna 18 is operated, radio waves are transmitted toward the IC tag 19. A broken line in the figure represents a range where the antenna 18 can communicate, that is, a communication area 110.

  When the IC tag 19 moves in the moving direction 20 indicated by the arrow, the IC tag 19 attached to a person or a bag is detected first by the first detection sensor 21 and then by the second detection sensor 22. . Thereby, the moving direction of the IC tag 19 can be determined.

  As a method of determining a moving direction using a plurality of sensors as described above, for example, Patent Document 1 discloses a passerby entrance / exit management system. In patent document 1, the 1st sensor and 2nd sensor which consist of an infrared sensor are installed along the passage direction in the gate which goes in and out of the security zone where an outsider's entry is restricted, and a passerby possesses A configuration in which a third sensor that detects a weak radio wave waveform from a tag is also installed is disclosed. In Patent Literature 1, the movement direction of the passerby is determined based on the detection order of the first sensor and the second sensor, and the passerby is specified based on the detection information of the third sensor.

JP 2003-303382 A

  In order to determine the moving direction of the IC tag, the conventional RFID system as shown in FIG. 7 needs to be additionally provided with a plurality of detection sensors for detecting a person or a baggage, which is necessary for installation as the price of the system increases. There is a problem that a large space becomes large. Furthermore, when a plurality of people and packages pass at the same time, there is a problem that the determination of the moving direction cannot be performed reliably.

  The present invention has been made to solve the above-described problem, and an object thereof is an RFID system and a moving direction determination method capable of reliably determining the moving direction of an IC tag without using a special sensor. Is to provide.

  The present invention reads the identification information of the IC tag with a plurality of antennas included in the RFID reader, records the identification information, the reading time, and the reading signal level or the number of readings at the reading time. Subtracting the reading signal level or the number of readings to sequentially calculate the difference, cumulatively adding the difference, further cumulatively adding the cumulative addition value to calculate a final value, and using the final value, the IC tag It is characterized by determining the moving direction.

  That is, according to the present invention, an IC tag attached to a movable object and an RFID reader that performs wireless communication with the IC tag are provided, and the RFID reader is at least part of a range that can communicate with the IC tag. Receiving means for reading the identification information of the IC tag by the antenna for each unit time that is a preset fixed time, and a plurality of antennas arranged along the movement path so as to overlap, Recording means for recording a reading time and a reading signal level at the reading time, a first antenna and a second antenna are selected from the plurality of antennas, and the respective reading signal levels are extracted, and at the same reading time Subtracting the read signal level of the second antenna from the read signal level of the first antenna. A calculation means for sequentially calculating a difference, accumulating the difference, further accumulating the accumulated addition value to calculate a final value, and a determination means for determining a moving direction of the IC tag based on the final value An RFID system characterized by being constructed is obtained.

  In addition, according to the present invention, an IC tag attached to a movable object and an RFID reader that performs wireless communication with the IC tag are provided, and the RFID reader is at least part of a range that can communicate with the IC tag. Receiving means for reading the identification information of the IC tag by the antenna for each unit time that is a preset fixed time, and a plurality of antennas arranged along the movement path so as to overlap, Recording means for recording the reading time and the number of readings at the reading time, and selecting the first antenna and the second antenna from the plurality of antennas, extracting each of the reading times, and at the same reading time, The difference is sequentially calculated by subtracting the number of readings of the second antenna from the number of readings of the first antenna, and the difference is accumulated. An RFID system comprising: calculating means for adding and further adding cumulatively added values to calculate a final value; and determining means for determining a moving direction of the IC tag based on the final value Is obtained.

  The present invention further includes an IC tag attached to a movable object, an RFID reader that wirelessly communicates with the IC tag, and a server device that communicates with the RFID reader. It has a plurality of antennas arranged along the movement path so that at least a part of a range communicable with the IC tag is overlapped, and the IC tag is identified by the antenna every unit time that is a predetermined time. Receiving means for reading information, recording means for recording the identification information, reading time and reading signal level at the reading time, and transmitting means for transmitting the identification information and the reading signal level to the server device. The server device selects a first antenna and a second antenna from the plurality of antennas, and reads each of the reading antennas. Extract the signal level, subtract the read signal level of the second antenna from the read signal level of the first antenna at the same reading time, sequentially calculate the difference, cumulatively add the difference, An RFID system comprising an arithmetic means for calculating a final value by further cumulatively adding the cumulatively added values and a determination means for determining a moving direction of the IC tag based on the final values is obtained. .

  The present invention further includes an IC tag attached to a movable object, an RFID reader that wirelessly communicates with the IC tag, and a server device that communicates with the RFID reader. It has a plurality of antennas arranged along the movement path so that at least a part of a range communicable with the IC tag is overlapped, and the IC tag is identified by the antenna every unit time that is a predetermined time. A receiving means for reading information; a recording means for recording the identification information, a reading time and a reading count at the reading time; and a transmitting means for transmitting the identification information and the reading count to the server device, The server device selects a first antenna and a second antenna from the plurality of antennas, and sets each of the number of reading times. Subtracting the number of readings of the second antenna from the number of readings of the first antenna at the same reading time, sequentially calculating a difference, cumulatively adding the difference, and further adding the cumulatively added value An RFID system comprising an arithmetic means for calculating the final value by cumulative addition and a determination means for determining the moving direction of the IC tag based on the final value is obtained.

  In addition, according to the present invention, it is possible to obtain the above RFID system characterized in that the moving direction of the IC tag is determined by the sign of the final value.

  In addition, according to the present invention, it is possible to obtain the RFID system described above, wherein the moving direction of the IC tag is determined when the absolute value of the final value exceeds a preset threshold value.

  Further, according to the present invention, an IC tag attached to a movable object and an RFID reader that wirelessly communicates with the IC tag are configured, and the RFID reader is at least one of a range that can communicate with the IC tag. Reading the identification information of the IC tag with a plurality of antennas arranged along the movement path so that the parts overlap each other at a predetermined unit time, the identification information, the reading time, and the reading Recording a read signal level at a time; selecting a first antenna and a second antenna from the plurality of antennas; extracting the respective read signal levels; and the first antenna at the same read time The difference is sequentially calculated by subtracting the read signal level of the second antenna from the read signal level of A step of cumulatively adding the differences; a step of further cumulatively adding the cumulatively added values to calculate a final value; and a step of determining a moving direction of the IC tag based on the final value. A moving direction determination method is obtained.

  Further, according to the present invention, an IC tag attached to a movable object and an RFID reader that wirelessly communicates with the IC tag are configured, and the RFID reader is at least one of a range that can communicate with the IC tag. Reading the identification information of the IC tag with a plurality of antennas arranged along the movement path so that the parts overlap each other at a predetermined unit time, the identification information, the reading time, and the reading Recording the number of readings at a time; selecting a first antenna and a second antenna from the plurality of antennas; extracting each of the number of readings; and Subtracting the number of readings of the second antenna from the number of readings to sequentially calculate a difference; and accumulating the difference. A moving direction determination method, comprising: a step of adding, a step of further cumulatively adding the cumulatively added values to calculate a final value, and a step of determining a moving direction of the IC tag based on the final value. can get.

  Further, according to the present invention, an IC tag attached to a movable object, an RFID reader that performs wireless communication with the IC tag, and a server device that communicates with the RFID reader, the RFID reader includes: The step of reading the identification information of the IC tag every unit time that is a predetermined time with a plurality of antennas arranged along a movement path so that at least a part of a range communicable with the IC tag overlaps And a step of recording the identification information, a reading time and a reading signal level at the reading time, and a step of transmitting the identification information and the reading signal level to the server device. The first antenna and the second antenna are selected from the two antennas, and the respective read signal levels are extracted. Subtracting the read signal level of the second antenna from the read signal level of the first antenna at the same reading time, sequentially calculating a difference, accumulating the difference, and accumulating There is obtained a moving direction determination method comprising the steps of further accumulating the added values to calculate a final value and determining the moving direction of the IC tag based on the final value.

  Further, according to the present invention, an IC tag attached to a movable object, an RFID reader that performs wireless communication with the IC tag, and a server device that communicates with the RFID reader, the RFID reader includes: The step of reading the identification information of the IC tag every unit time that is a predetermined time with a plurality of antennas arranged along a movement path so that at least a part of a range communicable with the IC tag overlaps And a step of recording the identification information, a reading time and a reading count at the reading time, and a step of transmitting the identification information and the reading count to the server device, wherein the server device includes the plurality of antennas. The first antenna and the second antenna are selected from the above, and the number of times of reading each is extracted, and the same reading is performed. Subtracting the number of readings of the second antenna from the number of readings of the first antenna at a time, sequentially calculating a difference, cumulatively adding the difference, and a cumulative added value There is obtained a moving direction determination method characterized by having a step of calculating a final value by cumulative addition and a step of determining a moving direction of the IC tag based on the final value.

  According to the present invention, the moving direction determination method described above is characterized in that the moving direction of the IC tag is determined based on the sign of the final value.

  According to the present invention, it is possible to obtain the above moving direction determination method, wherein the moving direction of the IC tag is determined when the final value exceeds a preset threshold value.

  According to the present invention, it is possible to provide an RFID system and a moving direction determination method that can reliably determine the moving direction of an IC tag without using a special sensor.

1 is a block diagram illustrating an RFID system according to the present invention. The flowchart explaining the moving direction determination method by this invention. The figure which shows the simulation result which concerns on embodiment of this invention. 3A shows the read signal level, FIG. 3B shows the difference in the read signal level, FIG. 3C shows the value obtained by accumulating the difference, and FIG. 3D shows the difference in FIG. The final value obtained by cumulatively adding the values of. The figure which shows the simulation result which concerns on other embodiment of this invention. 4A shows the read signal level, FIG. 4B shows the difference in the read signal level, FIG. 4C shows the value obtained by cumulatively adding the differences, and FIG. 4D shows the difference in FIG. The final value obtained by cumulatively adding the values of. The figure which shows the moving direction determination result which concerns on Example 1 of this invention. 5A shows the read signal level, FIG. 5B shows the difference in the read signal level, FIG. 5C shows the value obtained by cumulatively adding the differences, and FIG. 5D shows the difference in FIG. The final value obtained by cumulatively adding the values of. The figure which shows the moving direction determination result which concerns on Example 2 of this invention. 6A shows the number of readings, FIG. 6B shows the difference in the number of readings, FIG. 6C shows the value obtained by cumulatively adding the differences, and FIG. 6D shows the value shown in FIG. The final value of cumulative addition. The block diagram explaining the moving direction determination method using the conventional RFID system.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

  FIG. 1 is a block diagram illustrating an RFID system according to the present invention. FIG. 2 is a flowchart for explaining a moving direction determination method according to the present invention. 1 and 2 show an example in which two antennas are used. An RFID reader 1 is incorporated in a gate through which an IC tag 9 attached to a person or a baggage passes. The RFID reader 1 includes a first antenna 6 and a second antenna along a movement path of the IC tag 9. The antenna 7 is arranged. When the RFID reader 1 communicates with the IC tag 9, the logic circuit 3 performs encoding and decoding according to an instruction from the control circuit 2, and the high-frequency analog circuit 4 performs analog signal amplification and transmission / reception separation. The antenna switch circuit 5 performs operations, switching, and the like of the first antenna 6 and the second antenna 7, and transmits radio waves from the first antenna 6 and the second antenna 7 toward the IC tag 9 during operation. A broken line in the figure indicates a communication area of each antenna.

  In the present embodiment, the cumulative addition value and the final value are set to 0 (step 0) before reading of the IC tag 9 by each antenna starts. When the IC tag 9 moves in the moving direction 10 indicated by the arrow, the communication first overlaps the communication area 101 of the first antenna 6 and then partially overlaps the communication area of the first antenna 6 and the second antenna 7. In the area 102, finally, in the communication area 103 of the second antenna 7, the identification information of the IC tag 9 is read every predetermined unit time (step 1).

  The read identification information is recorded in the control circuit 2 together with the reading time and the reading signal level or the number of readings (step 2). Further, the control circuit 2 subtracts the value of the antenna 7 from the value of the antenna 6 with respect to the read signal level or the number of times of reading at the same reading time, and sequentially calculates the difference (step 3). Calculate the cumulative added value (added to the cumulative added value up to the previous reading time) (step 4), and further add this cumulative added value (add to the final value up to the previous reading time) (Yes) Calculate the final value (Step 5) Perform the calculation process. The above steps are repeated until reading is completed (step 6). When the reading of both the first antenna 6 and the second antenna 7 is finally completed, the moving direction of the IC tag 9 is determined using the sign of the final value (step 7). In addition, it is also possible to provide a server device such as a computer separately from the RFID reader 1 and transmit the read signal level or the read count recorded by the control circuit 2 to the server device and perform the above arithmetic processing and determination in the server device. It is. It is also possible to perform the above arithmetic processing and determination offline after acquiring all information.

  An IC tag moving direction determination method will be described in detail using a simulation embodiment. In the present embodiment, the moving direction of the IC tag is determined based on the sign of the final value. When the sign is positive, the moving direction is 10 and when the sign is negative, the moving direction is opposite to the moving direction 10. It was supposed to move.

  3A and 3B are diagrams showing simulation results according to the embodiment of the present invention. FIG. 3A shows a read signal level, FIG. 3B shows a difference in read signal level, and FIG. A value obtained by accumulating the difference, FIG. 3D shows a final value obtained by accumulating the value shown in FIG. Here, the horizontal axis indicates the elapsed time t for each unit time, and the time elapses from left to right. Here, a simulation was performed using the read signal level when the IC tag 9 moves in the direction from the first antenna 6 to the second antenna 7 shown in FIG. In the present embodiment, a simulation is performed for the case where the IC tag 9 moves at a substantially constant speed.

  3A, P1 indicates the read signal level of the first antenna 6, and P2 indicates the read signal level of the second antenna 7. In FIG. In the calculation processing of the present embodiment, first, as shown in FIG. 3B, P2 is subtracted from P1 to calculate a difference (P1-P2). Next, as shown in FIG. 3C, the difference of FIG. 3B is cumulatively added to calculate a cumulative added value (Σ (P1-P2)). Further, the cumulative addition values in FIG. 3C are cumulatively added once again to calculate the final value (Σ {Σ (P1-P2)}). The sign of this final value is positive, and it can be determined that the IC tag is moving in the moving direction 10.

  4A and 4B are diagrams showing simulation results according to another embodiment of the present invention. FIG. 4A is a read signal level, FIG. 4B is a read signal level difference, and FIG. Is a value obtained by accumulating the differences, and FIG. 4D is a final value obtained by accumulating the values shown in FIG. Here, the horizontal axis indicates the elapsed time t for each unit time, and the time elapses from left to right. Here, a simulation was performed using the read signal level when the IC tag 9 moves in the direction from the second antenna 7 to the first antenna 6 shown in FIG. In the present embodiment, a simulation is performed for the case where the IC tag 9 moves at a substantially constant speed.

  Also in FIG. 4A, P1 indicates the read signal level of the first antenna 6, and P2 indicates the read signal level of the second antenna 7. As in the case of FIG. 2, the calculation process of the present embodiment first calculates P (P1-P2) by subtracting P2 from P1, as shown in FIG. 4 (b). Next, as shown in FIG. 4C, the difference of FIG. 4B is cumulatively added to calculate a cumulative added value (Σ (P1-P2)). Further, the cumulative addition value of FIG. 4C is cumulatively added once again to calculate the final value (Σ {Σ (P1-P2)}). The sign of this final value is negative, and it can be determined that the IC tag is moving in the direction opposite to the moving direction 10.

  In this embodiment, the read signal level is arithmetically processed and the moving direction of the IC tag is determined. However, even when this read signal level is replaced with the number of times of reading and the same arithmetic processing is performed, the effect of the present invention is obtained. It was also confirmed by simulation that it was obtained.

  Further, a process may be added in which a threshold is set in advance for the absolute value of the final value, and the determination is performed only when the absolute value of the final value is equal to or greater than the threshold. For example, when the IC tag is attached at a position where it is difficult to read, or when reading is performed after passing through the communication area in a place where a radio wave is reflected, etc., the IC tag There is a possibility that reading errors and variations occur in communication between the antennas of the RFID reader. In such a case, it is possible to prevent erroneous determination by setting the threshold value and narrowing the determination range. This threshold value may be appropriately set according to the use situation and the surrounding environment. Furthermore, although the above description shows an example in the case of one IC tag, even if a plurality of IC tags move at the same time, the arithmetic processing described above may be performed for each identification information of each IC tag.

Example 1
In Example 1, when the IC tag 9 shown in FIG. 1 moved from the first antenna 6 to the second antenna 7, the read signal level was measured, the calculation was performed, and an experiment for determining the moving direction was performed. . When the final value has a positive sign, the IC tag 9 moves from the first antenna 6 to the second antenna 7, and when the final value has a negative sign, it is determined to move in the opposite direction. Was set as follows.

  5A and 5B are diagrams showing the moving direction determination result according to the first embodiment of the present invention. FIG. 5A shows the read signal level, FIG. 5B shows the difference in the read signal level, and FIG. Is a value obtained by accumulating the differences, and FIG. 5D is a final value obtained by accumulating the values shown in FIG. As a result of performing the arithmetic processing of the present invention, the sign of the final value shown in FIG. 5D is positive, and it can be correctly determined that the first antenna 6 has moved to the second antenna 7.

(Example 2)
In Example 2, an experiment was performed in which the number of readings was measured when the IC tag 9 shown in FIG. 1 moved from the first antenna 6 to the second antenna 7, the calculation was performed, and the moving direction was determined. As in the first embodiment, when the final value has a positive sign, the IC tag 9 moves from the first antenna 6 to the second antenna 7, and when the final value has a negative sign, It was set to determine that it would move in the opposite direction.

  FIG. 6 is a diagram illustrating the moving direction determination result according to the second embodiment of the present invention. FIG. 6A illustrates the number of readings, FIG. 6B illustrates the difference in the number of readings, and FIG. A value obtained by cumulatively adding the differences, FIG. 6D, is a final value obtained by cumulatively adding the values shown in FIG. In FIG. 6A, N1 indicates the number of readings of the first antenna 6, and N2 indicates the number of readings of the second antenna 7. In the arithmetic processing of this embodiment, first, as shown in FIG. 6B, N2 is subtracted from N1 to calculate a difference (N1-N2). Next, as shown in FIG. 6C, the difference of FIG. 6B is cumulatively added to calculate a cumulative added value (Σ (N1-N2)). Further, the cumulative addition value of FIG. 6C is cumulatively added once again to calculate the final value (Σ {Σ (N1-N2)}). As a result of the arithmetic processing of the present invention, the sign of the final value shown in FIG. 6D is positive, and it has been correctly determined that the first antenna 6 has moved to the second antenna 7.

  The embodiments and examples of the present invention have been described with reference to the drawings. However, the present invention is not limited to these embodiments, and changes in members and configurations are within the scope of the present invention. Is included in the present invention. For example, the configuration of the antenna is not limited to two, and the moving direction of the IC tag is similarly determined by applying the arithmetic processing of the present invention to the reading result of the IC tag when a plurality of antennas are installed. It goes without saying that it is possible.

  Moreover, no matter how the elapsed time t for each unit time is set, there is no problem in the determination as long as the context of the elapsed time is correctly recognized. That is, it is obvious that various modifications and corrections that can be naturally made by those skilled in the art are also included in the present invention.

1, 11 RFID reader 2, 12 Control circuit 3, 13 Logic circuit 4, 14 High-frequency analog circuit 5, 15 Antenna switch circuit 6 First antenna 7 Second antenna 18 Antenna 9, 19 IC tag 10, 20 Moving direction 21 First detection sensor 22 Second detection sensor 101, 102, 103, 110 Communication area

Claims (12)

  An IC tag attached to a movable object, and an RFID reader that performs wireless communication with the IC tag, the RFID reader along the movement path so that at least a part of a range that can communicate with the IC tag overlaps. And receiving means for reading the identification information of the IC tag by the antenna for each unit time that is a preset fixed time, the identification information, the reading time, and the reading time Recording means for recording a read signal level, a first antenna and a second antenna are selected from the plurality of antennas, the respective read signal levels are extracted, and the first antenna at the same reading time Subtracting the read signal level of the second antenna from the read signal level to calculate the difference sequentially, RFID comprising: arithmetic means for performing product addition and further cumulatively adding the cumulative addition values to calculate a final value; and determination means for determining a moving direction of the IC tag based on the final value system.   An IC tag attached to a movable object, and an RFID reader that performs wireless communication with the IC tag, the RFID reader along the movement path so that at least a part of a range that can communicate with the IC tag overlaps. And receiving means for reading the identification information of the IC tag by the antenna for each unit time that is a preset fixed time, the identification information, the reading time, and the reading time Recording means for recording the number of readings, the first antenna and the second antenna are selected from the plurality of antennas, the number of readings is extracted, and the number of readings of the first antenna at the same reading time Subtracting the number of readings of the second antenna from the above to sequentially calculate the difference, cumulatively adding the difference, cumulative addition RFID system comprising a calculation means for calculating the final value by further cumulatively adding the value, in that they are composed of a determining means for determining a moving direction of the IC tag by the final value.   An IC tag attached to a movable object, an RFID reader that wirelessly communicates with the IC tag, and a server device that communicates with the RFID reader, wherein the RFID reader is in a range that can communicate with the IC tag. A plurality of antennas arranged along the movement path so that at least a part thereof overlaps, and receiving means for reading the identification information of the IC tag by the antenna for each unit time that is a predetermined time, and It comprises: recording means for recording the identification information, the reading time and the reading signal level at the reading time; and a transmission means for transmitting the identification information and the reading signal level to the server device. The first antenna and the second antenna are selected from the antennas, and the respective read signal levels are extracted. The difference is sequentially calculated by subtracting the read signal level of the second antenna from the read signal level of the first antenna at the same reading time, and the difference is cumulatively added. Further, an RFID system comprising: an arithmetic unit that calculates a final value by cumulative addition; and a determination unit that determines a moving direction of the IC tag based on the final value.   An IC tag attached to a movable object, an RFID reader that wirelessly communicates with the IC tag, and a server device that communicates with the RFID reader, wherein the RFID reader is in a range that can communicate with the IC tag. A plurality of antennas arranged along the movement path so that at least a part thereof overlaps, and receiving means for reading the identification information of the IC tag by the antenna for each unit time that is a predetermined time, and A recording unit that records identification information, a reading time, and a reading count at the reading time; and a transmission unit that transmits the identification information and the reading count to the server device, wherein the server device includes the plurality of antennas. The first antenna and the second antenna are selected from the above, and the number of times of reading each is extracted, and at the same reading time , Subtracting the number of readings of the second antenna from the number of readings of the first antenna, sequentially calculating the difference, cumulatively adding the difference, and further cumulatively adding the cumulative addition value to the final An RFID system comprising: an arithmetic unit that calculates a value; and a determination unit that determines a moving direction of the IC tag based on the final value.   The RFID system according to any one of claims 1 to 4, wherein the moving direction of the IC tag is determined based on a sign of the final value.   The RFID system according to any one of claims 1 to 5, wherein when the absolute value of the final value exceeds a preset threshold value, the moving direction of the IC tag is determined. .   It is composed of an IC tag attached to a movable object and an RFID reader that performs wireless communication with the IC tag, and the RFID reader is placed on the movement path so that at least a part of a range that can communicate with the IC tag overlaps. The step of reading the identification information of the IC tag, and the identification information, the reading time, and the reading signal level at the reading time are recorded for each unit time that is a predetermined fixed time by a plurality of antennas arranged along Selecting a first antenna and a second antenna from the plurality of antennas, extracting each of the read signal levels, and calculating the first antenna from the read signal level of the first antenna at the same reading time. Subtracting the read signal level of two antennas to sequentially calculate the difference; and A moving direction determination method comprising: a product adding step; a step of further cumulatively adding the cumulatively added values to calculate a final value; and a step of determining a moving direction of the IC tag based on the final value. .   It is composed of an IC tag attached to a movable object and an RFID reader that performs wireless communication with the IC tag, and the RFID reader is placed on the movement path so that at least a part of a range that can communicate with the IC tag overlaps. The step of reading the identification information of the IC tag, and the identification information, the reading time, and the number of readings at the reading time are recorded for each unit time which is a predetermined fixed time by a plurality of antennas arranged along Selecting a first antenna and a second antenna from the plurality of antennas, extracting the number of readings of each, and calculating the second antenna from the number of readings of the first antenna at the same reading time Subtracting the number of readings and sequentially calculating the difference, and cumulatively adding the difference; Moving direction determination method comprising the steps of calculating the final value by further cumulatively adds the products added value, to have the step of determining a moving direction of the IC tag by the final value.   An IC tag attached to a movable object, an RFID reader that wirelessly communicates with the IC tag, and a server device that communicates with the RFID reader, and the RFID reader can communicate with the IC tag Reading the identification information of the IC tag with a plurality of antennas arranged along the movement path so that at least a part of the identification tag overlaps each unit time that is a predetermined time, and the identification information and the reading time And a step of recording a read signal level at the read time, and a step of transmitting the identification information and the read signal level to the server device, wherein the server device includes a first antenna from the plurality of antennas. Select the second antenna, extract the respective read signal levels, and the same read time And subtracting the read signal level of the second antenna from the read signal level of the first antenna to sequentially calculate a difference, accumulating the difference, and a cumulative added value. The method further comprises a step of calculating a final value by cumulative addition and a step of determining a moving direction of the IC tag based on the final value.   An IC tag attached to a movable object, an RFID reader that wirelessly communicates with the IC tag, and a server device that communicates with the RFID reader, and the RFID reader can communicate with the IC tag Reading the identification information of the IC tag with a plurality of antennas arranged along the movement path so that at least a part of the identification tag overlaps each unit time that is a predetermined time, and the identification information and the reading time And a step of recording the number of readings at the reading time, and a step of transmitting the identification information and the number of readings to the server device, wherein the server device includes a first antenna and a second antenna from the plurality of antennas. The antenna is selected, the number of times of reading is extracted, and the first reading at the same reading time is selected. Subtracting the number of readings of the second antenna from the number of readings of the antenna to sequentially calculate the difference, cumulatively adding the difference, and cumulatively adding the cumulatively added values to obtain a final value A moving direction determination method comprising: a step of calculating; and a step of determining a moving direction of the IC tag based on the final value.   11. The moving direction determination method according to claim 7, wherein the moving direction of the IC tag is determined based on a sign of the final value.   The moving direction according to any one of claims 7 to 11, wherein the moving direction of the IC tag is determined when an absolute value of the final value exceeds a preset threshold value. Judgment method.

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