JP2013104845A - Position information detection system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a position information detection system capable of highly accurately locating an IC tag equipped with no clocks in terms of the position of the searched IC tag itself.SOLUTION: A position information detection system comprises: readers/writers, each having reply setting request means which requests a setting for receiving first information and replying with second information for a particular IC tag, and transceiving processing means which transmits the first information and records the time of transmission, and then receives the second information and records the time of reception; IC tags, each having reply setting execution means which executes the setting in response to the setting request, and reply processing means which receives the first information and transmits the second information after a certain delay time; and a position information processor having position derivation means which derives position of the particular IC tag on the basis of the position of the corresponding reader/writer, the time of transmission, the time of reception, and the delay time.

Description

  The present invention belongs to the technical field of RFID (radio frequency identification). In particular, the present invention relates to a system for detecting position information of articles, people, etc. in warehouses, stores, offices, etc. using IC tags, communication devices, etc. for article inventory management, personnel movement management, etc.

When searching for items in a specific area, such as inventory in a warehouse, work in process in a factory, collection in a library, goods in a department store, guests in a hotel, employees in an office, etc. A technology for accurately detecting the presence / absence and the location of these is required.
For example, when a received signal matches a recognition number representing an object, a communication tag having means for generating sound, light, and a response signal, and one portable wireless transmitter that transmits a signal that identifies the communication tag, There is known an invention of an object location detection system constituted by: In this system, a plurality of communication tags attached to a product, its packaging or storage shelf, etc. are scanned over a wide area so that only the communication tag attached to the target product emits sound, light, and a response signal. (Patent Document 1).
In addition, a base station that is provided for each area gate and receives IC tag information passing through the gate, detects the IC tag moving direction, IC tag information received by the base station, and IC tag movement A center that receives information indicating a direction, and the center creates position information indicating an area where the IC tag exists based on the received IC tag information and the information indicating the moving direction of the IC tag, An invention of a position detection system that forms a database of position information is known. In this system, the current position of the subject can be confirmed reliably and accurately using an IC tag (Patent Document 2).
Also, a first wireless transmitter provided on one or a plurality of search objects and capable of transmitting identification information of the search object, and a radio transmitted from the first wireless transmitter can be received and moved. A possible first wireless receiver and position detecting means for detecting a moving position of the first wireless receiver, the first wireless receiver is moved and searched, and the distance to the search target is When it is within a predetermined communication area set in advance, the presence of the search target is received as the identification information by the first wireless receiver, and transmitted to the position detecting means, and the first wireless There is known an invention of a position search system in which a reception position of a receiver is obtained by the position detection means as an existence position of the search object. In this system, the position and identification information for each item placed on an indoor shelf or the like can be detected in a non-contact and high accuracy (Patent Document 3).

JP2003-23385 JP-A-2005-64725 JP2005-140637

By the way, GPS (Global Positioning System) is mentioned as the most famous position information detection system. GPS is a system for specifying a position using radio waves emitted from GPS satellites orbiting the earth and time information of a clock mounted on a receiving terminal. It is used in many systems such as car navigation systems and mobile phones, and it is possible to calculate the current location of the receiving terminal. These systems using GPS have a problem that the receiving terminal must be equipped with an accurate clock to some extent, and the position cannot be detected by an object such as a general IC tag that does not have a built-in clock. . In addition, there is a problem that high-accuracy position detection, in which the accuracy changes depending on the number of receivable satellites, is difficult for consumer use.
There is also a problem in a system that uses an IC tag that exemplifies the above prior art document. In Patent Document 1, there is a problem that the position of the IC tag that generates sound and light is the position of the IC tag to be searched, and the position of the IC tag to be searched cannot be directly detected as the position. Further, in Patent Document 2, since the detection position of the IC tag to be searched is the gate arrangement position, there is a problem that it cannot be detected with an accuracy exceeding the gate arrangement interval. Further, in Patent Document 3, it is necessary to bring the reception position of the first wireless receiver close to the position of the IC tag to be searched. Therefore, it cannot be detected when the position of the IC tag to be searched is completely unknown. There's a problem.

  The present invention has been made to solve the above problems. The purpose is to detect the position of the IC tag without a clock, and not the position of the receiver, but the position of the IC tag to be searched for, so it is highly accurate without being restricted by the arrangement interval of the receiver. An object of the present invention is to provide a position information detection system that can detect and detect if the position of an IC tag to be searched is within the communication area even when the position of the IC tag to be searched is unknown.

The position information detection system according to claim 1 of the present invention is a position information detection system including a reader / writer, an IC tag, and a position information processing unit, and the reader / writer transmits the first information and transmits the transmission time. And a second transmission / reception processing means for receiving the second information and storing the reception time. The IC tag has a return processing means for receiving the first information and transmitting the second information. The processing unit includes delay time calculating means for calculating a delay time of a signal generated by the transmission / reception processing means and the reply processing means from the data lengths of the first information and the second information, the transmission time, the reception time, and the A position deriving unit for deriving the position of the IC tag based on the delay time and the position of the reader / writer is provided.
The position information detection system according to claim 2 of the present invention is the position information detection system according to claim 1, wherein the first information is a reader / writer ID for identifying a reader / writer that transmits the first information or a part thereof. The second information is an IC tag ID for specifying an IC tag whose position information is to be detected or a part thereof.
According to claim 3 of the present invention, in the position information detection system according to claim 1 or 2, the position information processing unit generates the first information and the second information. 2 information generating means, and first and second information setting means for setting the first information and the second information in a reader / writer and an IC tag.
A positional information detection system according to a fourth aspect of the present invention is the positional information detection system according to any one of the first to third aspects, wherein the processing by the transmission / reception processing means and the reply processing means is performed by the reader / writer. This is performed in synchronization with the transmission carrier wave.
A positional information detection system according to a fifth aspect of the present invention is the positional information detection system according to any one of the first to fourth aspects, which is a standard for a clock that gives the transmission time and the reception time in the reader / writer. The clock and the clock that generates the transmission carrier wave are the same or synchronized.
The positional information detection system according to a sixth aspect of the present invention is the positional information detection system according to the fifth aspect, wherein there are a plurality of reader / writers, and the clocks in the plurality of reader / writers are the same or synchronized. It is what you are doing.
A positional information detection system according to a seventh aspect of the present invention is the positional information detection system according to any one of the first to sixth aspects, wherein the positional information processing unit exists in a communication area of the reader / writer through the reader / writer. An IC tag ID acquiring means for acquiring an IC tag ID for specifying each IC tag, and the position information processing unit is a target for determining an IC tag for detecting position information from the acquired IC tag ID IC tag determining means is provided.
A positional information detection system according to an eighth aspect of the present invention is the positional information detection system according to any one of the first to seventh aspects, wherein the positional information processing unit is connected to the first of the reader / writers connected in communication. It has a transmission reader / writer determining means for determining a reader / writer for transmitting one information.
A positional information detection system according to a ninth aspect of the present invention is the positional information detection system according to any one of the first to eighth aspects, wherein the positional information processing unit is the first of the reader / writers connected in communication. 2 A receiving reader / writer determining means for determining a reader / writer for receiving information is provided.
The positional information detection system according to a tenth aspect of the present invention is the positional information detection system according to any one of the first to ninth aspects, wherein the position derivation means sets the electromagnetic wave velocity as c, (c × (( By calculating (reception time−transmission time) −delay time)) / 2 = a, it is derived that the IC tag is present in the vicinity of a circle having a radius a centered on the reader / writer as the position. Further, based on a plurality of circles obtained by the plurality of reader / writers having different arrangement positions, it is derived that the IC tag exists in the vicinity of the intersection of the plurality of circles as the position. .
A positional information detection system according to an eleventh aspect of the present invention is the positional information detection system according to any one of the first to ninth aspects, wherein there is one reader / writer that transmits the first information and stores a transmission time. The reader / writer that receives the second information and stores the reception time is a plurality of reader / writers, and the position deriving means determines the distance from the transmitting reader / writer to the IC tag as a, and from the IC tag to the IC tag. The distance to the receiving reader / writer is b, the electromagnetic wave velocity is c, and (c × ((reception time−transmission time) −delay time)) = a + b = L. The reader / writer that receives and the reader / writer that receives the signal have two focal points, and the sum of the distance from the reader / writer that transmits and the reader / writer that receives the signal to the IC tag is constant L (= a + b The presence of the IC tag in the vicinity of the ellipse is derived, and furthermore, based on the plurality of ellipses obtained by the plurality of receiving reader / writers having different arrangement positions, the position of the intersection of the plurality of ellipses is derived. It is derived that the IC tag exists in the vicinity.
A positional information detection system according to a twelfth aspect of the present invention is the positional information detection system according to any one of the first to ninth aspects, wherein the reader / writer stores the transmission time by transmitting the first information. The reader / writer that receives the second information and stores the reception time is a plurality of readers / writers, and the position deriving means a indicates the distance from the transmitting reader / writer to the IC tag, and Assuming that the reception time is reception time a, the distance from the IC tag to the receiving reader / writer is b, the reception time of the receiving reader / writer 1 is reception time b, and the electromagnetic wave velocity is c, (c × ((reception time b -Transmission time)-delay time))-(c x ((reception time a-transmission time)-delay time)) / 2 = (a + b)-a = b Reader It is derived that the IC tag exists in the vicinity of a circle whose center is the ita, and the distance from the receiving reader / writer to the IC tag is b, and further, a plurality of receiving reader / writers having different arrangement positions are used. Based on a plurality of obtained circles, it is derived that the IC tag is present in the vicinity of the intersection of the plurality of circles as the position.

  According to the present invention, it is possible to detect the position of an IC tag not equipped with a watch, and detect the position of the IC tag to be searched, not the position of the receiver, with high accuracy without being restricted by the arrangement interval of the receiver. A position information detection system is provided that can detect the position of an IC tag to be searched if it is within the communication area even when the position is unknown.

It is explanatory drawing which shows an example of the whole structure in the positional infomation detection system of this invention. It is explanatory drawing which shows an example of the operation principle in the positional information detection system of this invention. It is a block diagram (the 1) which shows an example of a structure in the positional infomation detection system of this invention. It is a block diagram (the 2) which shows an example of a structure in the positional infomation detection system of this invention. It is a chart figure showing an example of progress of time in transmission reception in a position information detection system of the present invention. It is a block diagram which shows an example (hardware structure) of the structure of the transmission / reception processing means in the reader / writer of the positional information detection system of this invention. It is a block diagram which shows an example (hardware structure) of the structure of the reply process means in the IC tag of the positional information detection system of this invention. It is a flowchart which shows an example of the operation | movement in the positional infomation detection system of this invention.

Next, embodiments of the present invention will be described with reference to the drawings. First, an overview of the overall configuration and its operation will be described, and details will be described later. An example of the overall configuration of the position information detection system of the present invention is shown in FIG. In FIG. 1, 1a to 1c are reader / writers, 2a to 2f are IC tags, and 3 is a position information processing unit.
The reader / writers 1a to 1c perform wireless communication with the IC tags 2a to 2f. Through the wireless communication, the reader / writers 1a to 1c transmit commands (commands) to the IC tags 2a to 2f and perform processing corresponding to the commands. For example, the reader / writers 1a to 1c read the IC tag ID and other stored data stored in the memories of the IC tags 2a to 2f. The reader / writers 1a to 1c write data to the memories of the IC tags 2a to 2f.
The reader / writers 1a to 1c have an anti-collision processing mechanism, and the IC tags 2a to 2f correspond to the anti-collision processing mechanism. Therefore, the reader / writers 1a to 1c can avoid communication and collisions with a plurality of IC tags even when a plurality of IC tags are simultaneously present in the communication area. It can be done selectively. As the anti-collision method, a known method such as a time domain multiple access (TDMA) or a modified method thereof can be applied.

The reader / writers 1a to 1c perform communication for detecting the distance between the reader / writers 1a to 1c and the IC tags 2a to 2f through wireless communication with the IC tags 2a to 2f. In order to detect the distance, one of the reader / writers 1a to 1c transmits the first information, the transmitted reader / writer stores the transmission time, and the IC tags 2a to 2f that have received the first information. When one of the reader / writers returns the second information and the transmitted reader / writer receives the second information, the reader / writer stores the reception time. At that time, a delay time from when the IC tag receives the first information to when the second information is returned can be calculated. If they are used, ((reception time-transmission time) -delay time) is the time required for the electromagnetic wave to reciprocate between the reader / writer and the IC tag. Therefore, ½ (half) of the value obtained by multiplying the time by the electromagnetic wave velocity is the distance between the reader / writer and the IC tag. In the example shown in FIG. 1, the position information processing unit 3 calculates the distance. Therefore, the reader / writer transmits the transmission time, the reception time, and the like as data necessary for the calculation to the position information processing unit 3 through a communication mechanism such as USB (Universal Serial Bus) or LAN.
Each of the plurality of reader / writers 1a to 1c has a clock mechanism that shares a single time (time that a single clock clocks). The time synchronization connection line shown in FIG. 1 is a connection line for sharing a single time in each of the plurality of reader / writers 1a to 1c. For example, the transmission time of the first information by one reader / writer and the reception time of the second information by a plurality of reader / writers are times based on the clock mechanism, that is, the time of one clock.

The IC tags 2a to 2f perform wireless communication with the reader / writers 1a to 1c. Through the wireless communication, commands (commands) from the reader / writers 1a to 1c are received, and processing corresponding to the commands is performed. For example, the IC tags 2a to 2f transmit the IC tag ID and other stored data stored in the memory to the reader / writers 1a to 1c through the wireless communication. The IC tags 2a to 2f write the data received from the reader / writers 1a to 1c into the memories of the IC tags 2a to 2f.
The IC tags 2a to 2f perform communication for detecting the distance between the IC tags 2a to 2f and the reader / writers 1a to 1c through wireless communication with the reader / writers 1a to 1c. Therefore, one of the IC tags 2a to 2f is set to transmit the second information when the first information is received. When the first information is transmitted from one reader / writer, the set IC tag receives it and transmits the second information. The process of transmitting the second information when receiving the first information operates in synchronization with a clock mechanism that shares a single time of the reader / writers 1a to 1c. The IC tags 2a to 2f themselves do not require a unique clock mechanism. Therefore, the delay time due to the processing can be calculated. Therefore, as described above, the distance between the reader / writer and the IC tag can be calculated.
The second information can be received by the plurality of reader / writers 1a to 1c. Accordingly, if the plurality of reader / writers 1a to 1c are set to receive the second information and store the reception time, the set reader / writer and the IC tag are set based on the stored reception time. Can be calculated.

The position information processing unit 3 is realized by software and hardware of a personal computer in the example shown in FIG. The position information processing unit 3 communicates with the reader / writers 1a to 1c through a communication mechanism such as USB or LAN. Through the communication, the position information processing unit 3 transmits a command (command) to the reader / writers 1a to 1c, and performs a process corresponding to the command. For example, through the communication, the position information processing unit 3 transmits a command for performing processing (for example, polling processing) for detecting the IC tags 2a to 2f existing in the communication areas of the reader / writers 1a to 1c, and the reader / writer 1a. The IC tag IDs collected from the IC tags 2a to 2f detected by each of -1c are received from each of the reader / writers 1a to 1c and stored in the memory as IC tag information.
The position information processing unit 3 specifies (determines) an IC tag whose position is to be detected, specifies (generates and sets) first information and second information, specifies (determines) a reader / writer that transmits the first information, The reader / writer that receives the second information is designated (determined). This designation is performed as a pre-stage process for detecting the position of the IC tag in accordance with an instruction input from the operator. When the transmission of the first information and the reception of the second information are performed by the designated reader / writer, the position information processing unit 3 receives the transmission time and the reception time from the reader / writer. The delay time from the reception of the first information to the return of the second information is a constant value determined by the data length of the first information and the second information. The position information processing unit 3 calculates the delay time. Further, the position information processing unit 3 stores each position (coordinates) of the reader / writers 1a to 1c as reader / writer information in a memory. Based on these data, the position information processing unit 3 performs processing for calculating the position of the designated IC tag.

  A process in which the position information processing unit 3 calculates the position of the IC tag will be described. An example of the operation principle in the position information detection system of the present invention is shown in FIG. 2 as an explanatory diagram. 2A shows a process of transmitting and receiving the first information and the second information, and FIG. 2B shows a process of calculating the position of the IC tag. In FIG. 2A, the time until the first information reaches the IC tag from the transmission / reception reader / writer is the same as the time until the second information reaches the transmission / reception reader / writer from the IC tag. Time Ta. The delay time from when the IC tag receives the first information to when the second information is returned is Td. The time until the second information reaches the receiving reader / writer from the IC tag is Tb. Here, it is assumed that the time when the transmission / reception reader / writer transmits the first information is T1, the time when the second information is received is T2, and the time when the reception reader / writer receives the second information is T3. At this time, Ta is T2−T1 = 2Ta + Td, and therefore, Ta = (T2−T1−Td) / 2. Also, Tb can be calculated by the following equation: T3−T1 = Ta + Td + Tb, and Tb = T3−T1−Ta−Td = T3−T2−2−3 × (T1 + Td) / 2.

In FIG. 2B, the position information processing unit 3 calculates the distance A from the transmission / reception reader / writer to the IC tag by applying an equation of A = c × Ta where the electromagnetic wave velocity is c. Can do. Since the position (coordinates) of the transmission / reception reader / writer is a fixed position registered in the position information processing unit 3, the IC tag exists on the circumference of a circle having a radius A from the position. Become. Similarly, the position information processing unit 3 can calculate the distance B from the receiving reader / writer to the IC tag by using an equation B = c × Tb. Since the position (coordinates) of the reception reader / writer is a position registered in the position information processing unit 3 at a fixed position, the IC tag exists on the circumference of a circle having a radius B from the position. Therefore, when the coordinates of the intersection of the two circles are calculated, the coordinates become the coordinates of the position where the IC tag exists.
As for the process of calculating the position of the IC tag, the process in the case of using two reader / writers of the transmission / reception reader / writer and the reception reader / writer has been described. If the number of reader / writers to be used is further increased, the position on the three-dimensional coordinate can be calculated as the position where the IC tag exists. In addition, the position information detection error can be reduced by calculating the position as an average value.

  Next, the configuration of the reader / writer, IC tag, and position information processing unit in the position information detection system of the present invention will be described in detail. An example of the configuration of the position information detection system of the present invention is shown in FIG. 3 and FIG. 4 as block diagrams. 3 and 4, 1 is a reader / writer, 2 is an IC tag, and 3 is a position information processing unit. In the reader / writer 1, 111 is an IC tag wireless communication means, 112 is an IC tag read / write means, 113 is a time management means, 114 is a PC interface, 115 is a transmission / reception processing means, 121 is first information, and 122 is second information. Information, 123 is a transmission time, 124 is a reception time, and 125 is a reader / writer ID. In the IC tag 2, 211 is a reader / writer wireless communication means, 212 is a reply processing means, 221 is first information, 222 is second information, and 223 is an IC tag ID. In the position information processing unit 3, 311 is a reader / writer interface, 312 is a delay time calculating means, 313 is a position deriving means, 314 is an IC tag ID obtaining means, 315 is a target IC tag determining means, and 316 is a transmission reader / writer decision. 317 is a receiving reader / writer determining unit, 318 is a first second information generating unit, 319 is a first second information setting unit, 321 is a delay time, 322 is first information, 323 is second information, and 324 is a reader Writer information 325 is IC tag information.

(In reader / writer 1)
The IC tag wireless communication means 111 is a wireless communication means for transmitting and receiving information between the reader / writer 1 and the IC tag 2. The IC tag wireless communication unit 111 generates a carrier wave, modulates the carrier wave with transmission information (for example, first information) generated for transmission by the IC tag read / write unit 112, the transmission / reception processing unit 115, and the like. Send it in the air as electromagnetic waves. Further, the IC tag wireless communication unit 111 receives and demodulates the electromagnetic wave transmitted from the IC tag 2 by the antenna, and the IC tag read / write unit 112 receives received information (for example, second information) obtained by the demodulation. The data is transferred to the transmission / reception processing means 115 and the like.
The IC tag wireless communication unit 111 can use a wireless communication unit of a wireless communication system compatible with RFID. However, for example, the international standard contact type (ISO / IEC 10536) and proximity type (ISO / IEC 14443), which are being promoted by ISO / IEC 18000, do not meet the intended purpose of the present invention because the communication distance is too short. It cannot be used as it is. ZigBee, Bluetooth (registered trademark), wireless LAN, UWB (Ultra Wide Band), and the like are known as short-range wireless standards corresponding to a communication distance of about 10 m to about 100 m. The frequency band in these standards exists in the range of about 800 MHz to about 11 GHz. In GPS, 1.6 GHz is used as a carrier wave. In the present invention, wireless communication means based on a standard whose frequency band is in the range of about 800 MHz to about 11 GHz can be suitably used. Further, it is possible to use a wireless communication means that changes the standard and adopts a wireless communication system adapted to the purpose of use of the present invention. The transmission and reception carrier frequencies may be the same, and transmission / reception may be performed in a time division manner. In addition, the transmission and reception carrier frequencies may be different, and transmission and reception may be performed simultaneously.

  The IC tag read / write unit 112 receives and reads the IC tag ID and other stored data stored in the memories of the IC tags 2a to 2f through the IC tag wireless communication unit 111. Further, the IC tag read / write unit 112 transmits the data through the IC tag wireless communication unit 111 and writes the data to the memories of the IC tags 2a to 2f. Further, the IC tag read / write unit 112 performs not only reading / writing to the memory but also processing performed by communication between the reader / writer 1 and the IC tag 2 according to a program (not shown) or the like (for example, authentication processing, Collision processing, etc.).

The time management means 113 is a clock mechanism for sharing a single time (time that one clock clocks) among each of the plurality of reader / writers 1. There is one original clock for determining the time, and the time is recorded in each of the plurality of reader / writers 1 in synchronization with the one source signal. The original clock may be provided inside the reader / writer 1 or outside the reader / writer 1. When the original clock is provided in the reader / writer 1, the other reader / writer 1 is synchronized with the original clock provided in one of the plurality of reader / writers 1 (or the other reader / writer 1 shares the original clock). . As the original clock, it is possible to use a high-precision crystal resonator whose temperature is made constant by a thermostatic bath. Of course, a primitive clock having higher accuracy such as GPS may be used.
In order to share a single time, the time management means 113 not only synchronizes but also adjusts the time for each of the plurality of reader / writers 1. For example, the trigger signal is superimposed on the time synchronization connection line (see FIG. 1) together with the original clock, and the time of each clock of the plurality of reader / writers 1 is set in synchronization with the reception of the trigger signal. The time (trigger signal delay time) for the trigger signal to reach each of the plurality of reader / writers 1 through the time synchronization connection line differs depending on the path length of the time synchronization connection line. Therefore, a time considering the trigger signal delay time is set for each of the plurality of reader / writers 1. In addition, although correction with respect to the relativity theoretical effect which arises by the relative motion of a GPS satellite, the gravity difference of outer space and the ground, etc. is required in GPS, in this invention, since it is a ground stationary system, it is required. do not do.
The time management means 113 generates a carrier wave clock of the IC tag wireless communication means 111 from the original clock. The frequency of the carrier wave for achieving the object of the present invention is adapted to the GHz band. When the frequency of the original clock does not match the desired frequency of the carrier wave, the desired frequency of the carrier wave is generated by dividing or multiplying the frequency of the original clock. That is, the original clock and the carrier wave are synchronized. Further, as will be described later, the process of receiving the first information 121 and transmitting the second information 122 performed when detecting the position information of the IC tag is performed as a process synchronized with the carrier wave of the reader / writer 1. Therefore, the entire signal processing for detecting the position information of the IC tag is synchronized with the original clock.

The PC interface 114 is an interface for the reader / writer 1 to transmit / receive information to / from the position information processing unit 3. In the example shown in FIG. 1, since the position information processing unit 3 is configured to be realized by a personal computer, the term “PC interface” is used. As the PC interface 114, USB, LAN, or the like can be used. Through the PC interface 114, the reader / writer 1 receives a command from the position information processing unit 3 and performs a process corresponding to the command. For example, the reader / writer ID 125, the IC tag ID 223, the transmission time 123, the reception time 124, the first information 121, the second information 123, and the like are transmitted and received.
The transmission / reception processing means 115 performs processing for transmitting the first information to the IC tag 2 whose position information is to be detected, storing the transmission time, receiving the second information, and storing the reception time. The processing performed by the transmission / reception processing unit 115 is performed under the management of the time management unit 113. Details of an example of a specific configuration of the transmission / reception processing unit 115 will be described later.

The first information 121 is information that the reader / writer 1 transmits to the IC tag 2 in order to detect position information. Only the IC tag 2 whose position information is to be detected responds to the first information 121, that is, returns the second information 122. The first information 121 requires a data length that can be distinguished from other information, but there is no particular limitation on the content thereof. For example, the first information 121 may be a reader / writer ID that identifies the reader / writer 1 that transmits the first information 121 or a part thereof. If the first information 121 is a reader / writer ID or a part thereof, the reader / writer ID is unique to the reader / writer 1, so that the position information processing unit 3 does not have to generate and set the first information 121.
The second information 122 is information for the reader / writer 2 to compare and verify whether or not the second information is received in a signal received by the reader / writer 1 as a reply of the IC tag 2 to the transmission of the first information by the reader / writer 1. .

The transmission time 123 is a time output by the time management means 113 when the reader / writer 1 transmits the first information. A predetermined time determined by the data length of the first information elapses from the start of transmission to the end of transmission, but the time is constant. Usually, since transmission is started by a trigger signal for starting transmission, if the time output by the time management means 113 is read (for example, latched) by the trigger signal, the transmission time 123 is the transmission start time. Of course, it may be the transmission end time calculated from the data length of the first information, and the position information processing unit 3 calculates the position in consideration of which is the transmission time 123.
The reception time 124 is a time output by the time management unit 113 when the reader / writer receives the second information. A predetermined time determined by the data length of the second information elapses from the start of reception to the end of reception, but the time is constant. Normally, since reception is detected by the end of reception, the reception time 124 is the reception end time. Of course, it may be the reception start time calculated from the data length of the second information, and the position information processing unit 3 calculates the position in consideration of which the reception time 123 is.
The reader / writer ID 125 is an ID (identification) uniquely assigned to each of the plurality of reader / writers 1. The reader / writer ID 125 is used by the position information processing unit 3 to identify one of a plurality of reader / writers.

(In IC tag 2)
The reader / writer wireless communication unit 211 is a wireless communication unit for the IC tag 2 to transmit / receive information to / from the reader / writer 1. The IC tag 2 performs processing corresponding to the command transmitted from the reader / writer 1 to the IC tag 2 through the reader / writer wireless communication unit 211. For example, the first information, the second information, the IC tag ID, and the like are transmitted / received. As the reader / writer wireless communication unit 211, a wireless communication unit of a wireless communication method that is compatible with the IC tag wireless communication unit 111 of the reader / writer 1 can be used.
The reply processing means 212 performs a process of receiving the first information 121 transmitted by the reader / writer 1 to notify the position information and transmitting the second information 222. The processing performed by the transmission / reception processing unit 115 is performed in synchronization with a carrier wave transmitted by the IC tag wireless communication unit 111 of the reader / writer 1. Details of an example of a specific configuration of the reply processing unit 212 will be described later.

The first information 221 is information for the IC tag 2 to compare and verify whether or not the first information is received in the signal received by the IC tag 2 with respect to the transmission of the first information by the reader / writer 1.
The second information 222 is information returned by the IC tag in response to the first information 121 transmitted by the reader / writer 1. The second information 222 only needs to be held by the IC tag 2 that is the target of detecting the position information. The second information 222 needs a data length that can be distinguished from other information, but there is no particular limitation on the content thereof. For example, the second information 222 may be an IC tag ID that identifies the IC tag 2 that transmits the second information 222 or a part thereof. When the second information 22 is an IC tag ID or a part thereof, the IC tag ID is unique to the IC tag 2, so that the position information processing unit 3 does not have to generate and set the second information 222.
The IC tag ID 223 is an ID (identification) uniquely assigned to each of the plurality of IC tags 2. The IC tag ID 223 is used by the reader / writer 1 to identify one of the plurality of IC tag IDs 223.

(In the position information processing unit 3)
The reader / writer interface 311 is an interface for the position information processing unit 3 to transmit / receive information to / from the reader / writer 1. As the reader / writer interface 311, USB, LAN, or the like can be used. The position information processing unit 3 transmits a command (command) to the reader / writer 1 through the reader / writer interface 311 and causes the reader / writer 1 to perform processing corresponding to the command. For example, the reader / writer ID 125, the IC tag ID 223, the transmission time 123, the reception time 124, the first information 121, the second information 123, and the like are transmitted and received.
The delay time calculation means 312 calculates a signal delay time 321 generated by the transmission / reception processing means 115 and the reply processing means 212 from the data lengths of the first information 322 and the second information 323. An example of the passage of time in transmission / reception in the position information detection system of the present invention is shown in FIG. 5 as a chart. In order to synchronize with the original clock of the time management means 113, a data transfer clock generated by dividing a carrier wave synchronized with the original clock is used. For example, transmission / reception is performed at a data transfer rate of M (bps: bits per second). Let's say. Further, it is assumed that the data length of the first information 322 is N1 (bit) and the data length of the second information 323 is N2 (bit). At this time, from the start to the end of one transmission or reception, the first information 322 requires N1 / M (sec) time, and the second information 323 requires N2 / M (sec) time. In addition, the synchronization processing circuit normally requires n data transfer clocks (n = 1, 2, 3,...) From the detection of reception until the start of transmission. . Therefore, as shown in FIG. 5, the reply processing means 212 has a delay time from the end of reception to the start of transmission of n / M (sec), and a delay time from the start of reception to the start of transmission of (N1 + n) / M ( sec), the delay time from the end of reception to the end of transmission is (N2 + n) / M (sec), the delay time from the start of reception to the end of transmission is (N1 + N2 + n) / M (sec), and so on. calculate. The transmission / reception processing means 115 calculates that the delay time from the start of transmission to the end of transmission is N1 / M (sec), and the delay time from the start of reception to the end of reception is N2 / M (sec). .

The position deriving unit 313 derives the position of the IC tag 2 based on the transmission time 123 and the reception time 124 in the transmission / reception processing unit 115, the position of the reader / writer 1, and the delay time 321.
The first method of position derivation is a method in which the reader / writer 1 that transmits the first information and stores the transmission time receives the second information and stores the reception time. In this case, the position deriving unit 313 calculates (c × ((reception time−transmission time) −delay time)) / 2 = a, where c is the electromagnetic wave velocity. By this calculation, the position deriving unit 313 has derived that the IC tag 2 exists in the vicinity of a circle having a radius a centered on the reader / writer 1 as a position. Further, based on a plurality of circles obtained by a plurality of reader / writers 1 having different arrangement positions, the position deriving means 313 calculates intersections of the plurality of circles as positions. By this calculation, the position deriving means 313 has derived that the IC tag 2 exists in the vicinity of the intersection, for example, the coordinates of the average value of the intersection. For example, assuming that the transmission time is the transmission start time and the reception time is the reception end time, the position deriving means 313 derives the position of the IC tag 2 by applying (N1 + N2 + n) / M (sec) as the delay time (FIG. 2, (See FIG. 5).

  In the second method for deriving the position, there is one reader / writer 1 that transmits the first information and stores the transmission time, and there are a plurality of reader / writers 1 that receive the second information and store the reception time. This is the case. In this case, the distance from the transmitting reader / writer 1 to the IC tag 2 is a, the distance from the IC tag 2 to the receiving reader / writer 1 is b, and the electromagnetic wave velocity is c. The position deriving unit 313 calculates (c × ((reception time−transmission time) −delay time)) = a + b = L. By this calculation, the position deriving means 313 takes the position of the reader / writer 1 for transmission and the reader / writer 1 for reception as two focal points, and the sum from the reader / writer 1 for transmission and the reader / writer 1 for reception to the IC tag is constant. It is derived that an IC tag exists in the vicinity of an ellipse that is L (= a + b). Further, based on a plurality of ellipses obtained by a plurality of receiving reader / writers 1 having different arrangement positions, the position deriving means 313 calculates intersections of the plurality of ellipses as positions. By this calculation, the position deriving means 313 has derived that the IC tag 2 exists in the vicinity of the intersection, for example, the coordinates of the average value of the intersection. For example, if the transmission time is the transmission end time and the reception time is the reception end time, the position deriving means 313 derives the position of the IC tag 2 by applying (N2 + n) / M (sec) as the delay time (FIG. 2, (See FIG. 5).

  Further, in the third method of position derivation, there is one reader / writer 1 that transmits the first information and stores the transmission time, and there are a plurality of reader / writers 1 that receive the second information and store the reception time. In some cases (same as the case of the second method). In this case, the position deriving means 313 indicates that the distance from the reader / writer 1 to be transmitted to the IC tag 2 is a, the reception time of the reader / writer 1 to be transmitted is the reception time a, and the distance from the IC tag 2 to the reader / writer 1 to be received. B, the reception time of the receiving reader / writer 1 is the reception time b, and the electromagnetic wave velocity is c. The position deriving means 313 calculates (c × ((reception time b−transmission time) −delay time)) − (c × ((reception time a−transmission time) −delay time)) / 2 = (a + b) −a = b. By this calculation, the position deriving unit 313 derives that the IC tag 2 exists in the vicinity of a circle whose center is the receiving reader / writer 1 and whose distance from the receiving reader / writer 1 to the IC tag 2 is b. It will be done. Further, based on the plurality of circles obtained by the plurality of receiving reader / writers 1 having different arrangement positions, the position deriving means 313 has derived that the IC tag 2 exists as a position near the intersection of the plurality of circles. become. For example, assuming that the transmission time is the transmission end time, the reception time a is the reception end time, and the reception time b is the reception end time, the position deriving means 313 applies n / M (sec) as the delay time to the IC tag 2 The position is derived (see FIGS. 2 and 5).

The IC tag ID acquisition unit 314 acquires an IC tag ID for specifying each IC tag 2 existing in the communication area of the reader / writer 1 through the reader / writer 1. Each of the plurality of reader / writers 1 performs a polling process, an anti-collision process, etc. in order to avoid a simultaneous collision with a plurality of IC tags 2 when a plurality of IC tags 2 exist in the communication area. Do. In the course of this processing, the IC tag ID acquisition unit 314 acquires an IC tag ID through each of the reader / writers 1. The IC tag ID acquisition unit 314 associates the acquired IC tag ID with the reader / writer ID that identifies the reader / writer 1 that detected it, and stores it in the IC tag information 325.
The target IC tag determining means 315 determines the target IC tag 2 from which the position information is detected from the acquired IC tag ID. For example, the target IC tag determining means 315 displays the IC tag information 324 as a list on the display (not shown) of the position information processing unit 3, and the IC tag ID designated and input by the operator from the list is displayed as the position information. The target IC tag 2 is to be detected.

The transmission reader / writer determining means 316 determines the reader / writer 1 that transmits the first information 321 from among the reader / writers 1 connected in communication. The position information processing unit 3 acquires the reader / writer ID of the reader / writer connected by communication through polling processing performed by the operating system of the personal computer. The transmission reader / writer determination means 316 stores the information as reader / writer information 323.
The receiving reader / writer determining means 317 determines the reader / writer 1 that receives the second information 322 from the reader / writers 1 connected for communication. For example, the receiving reader / writer determining means 317 displays the reader / writer information 323 as a list on a display (not shown) of the position information processing unit 3, and the reader / writer ID designated and input by the operator from the list is displayed as the position information. The reader / writer 1 to be detected is assumed. At this time, the reader / writer information 323 displayed on the display as a list by the receiving reader / writer determining unit 317 is limited to the reader / writer 1 that can detect the IC tag 2 determined as the target whose position information is detected by the target IC tag determining unit 315. To do.
The first second information generating unit 318 generates first information 322 and second information 323. The first second information generation unit 318 generates the first information 322 and the second information 323 as a part of the reader / writer ID and the IC tag ID or by generating a random number. For example, when the first information 121, 221 as a reader / writer ID or a part thereof and the second information 122, 222 as an IC tag ID or a part thereof are used as fixed values, the ID may be changed depending on the data length thereof. By overlapping, there is a possibility that a plurality of IC tags 2 respond and cause collision (interference) in communication. By generating the first information 322 and the second information 323, such a problem can be avoided.
The first second information setting means 319 sets the first information 322 and the second information 323 in the reader / writer 1 and the IC tag 2. Each of the first information 322 and the second information 323 generated by the first second information generation unit 318 is set as the first information 121 and the second information 122 of the reader / writer 1, respectively. To do. In addition, the first information 322 and the second information 323 generated by the first second information generating unit 318 are respectively used. The first and second information setting unit 319 is each of the first information 221 and the second information 222 of the IC tag 2. Is set through the reader / writer 1.

The first information 321 is data generated by the first second information generating unit 318. When the first information 321 is set in each of the reader / writer 1 and the IC tag 2 by the first second information setting means 319, it matches the first information 121, 221. The first information 321 is data for transmission when the reader / writer 1 performs transmission for detecting the position information of the IC tag 2.
The second information 322 is data generated by the first second information generating unit 318. When the second information 322 is set in each of the reader / writer 1 and the IC tag 2 by the first second information setting means 319, it matches the first information 122, 222. The second information 322 is data for reply when the IC tag 2 makes a reply for detecting the position information of the IC tag 2.
The reader / writer information 323 is data related to the reader / writer 1. For example, data such as a reader / writer ID that identifies the reader / writer 1, a position (coordinates) where the reader / writer 1 is installed, and whether or not communication connection to the position information processing unit 3 is possible.
The IC tag information 324 is data related to the IC tag 2. For example, the IC tag ID that identifies the IC tag 2, the position (coordinates) where the IC tag exists based on the position information detection data, whether or not wireless communication with the reader / writer 1 is possible, other systems (inventory management system, input Data (item name, person name, etc.) associated with each other obtained from the exit management system, etc.

The overall configuration has been described above. Next, the configuration of transmission / reception processing means in the reader / writer of the position information detection system of the present invention will be described. An example of the configuration (hardware configuration) of transmission / reception processing means in the reader / writer is shown in FIG. 6 as a block diagram.
The time latch A, time latch B, comparison data register, comparison means, reception data register, and transmission data register in FIG.
6 is the first information 121, the comparison data register in FIG. 6 is the second information 122, the time latch A in FIG. 6 is the transmission time 123, and the time latch B in FIG. Is stored (stored).
6 is the IC tag wireless communication means 111, the signal processing means in FIG. 6, the memory is the IC tag read / write means 112, the time generating means in FIG. 6, and the clock is the time management means 113. The I / F in FIG. 6 constitutes the PC interface 114. Note that two clocks are generated, a clock that gives the time of the transmission carrier and time generating means (original clock) and a clock that gives the timing of modulation (data transfer rate). These two clocks are synchronized.
The memory in FIG. 6 stores a reader / writer ID, data processed by the signal processing means, and the like.

In FIG. 6, the operation of the part constituting the transmission / reception processing means 115 will be described.
The first second information generating unit 318 generates first information 322 and second information 323. The first second information setting means 319 writes the first information 322 as the first information 121 in the reader / writer transmission data register and the second information 323 as the second information 122 in the comparison data register through the reader / writer interface 311.
Upon receiving a transmission start command from the position information processing unit 3, the reader / writer generates a transmission start trigger signal and serially transmits the first information in the transmission data register bit by bit through the transmission means (IC tag wireless communication means 111). Send. In response to the trigger signal, the time latch A stores the time output from the time generating means (stores all digits of the time in parallel). The stored time is transmission time 123 (in this example, transmission start time).
On the other hand, the receiving means of the reader / writer receives serially one bit at a time. The received data is serially sent bit by bit to the reception data register. The reception data register is a shift register, and each time 1-bit data is received, the data is serially sent bit by bit from the lower bit to the upper bit. The most significant bit of data is lost due to sequential feed. The comparison means always compares the second information in the comparison data register with all the digits of the data in the reception data register. When all the digits of the second information coincide with the data in the reception data register, the comparison means outputs a coincidence, that is, a reception end trigger signal. In response to the trigger signal, the time latch B stores the time output from the time generating means (stores all the digits of the time in parallel). The stored time is reception time 124 (in this example, reception end time).

The configuration of the transmission / reception processing unit has been described above. Next, the structure of the reply processing means in the IC tag of the position information detection system of the present invention will be described. An example (hardware configuration) of the reply processing means in the IC tag is shown as a block diagram in FIG.
The comparison data register, comparison means, reception data register, and transmission data register in FIG. Further, the receiving means and transmitting means in FIG. 7 constitute a reader / writer wireless communication means 211. Further, the signal processing means and the memory in FIG. 7 perform processing in which the IC tag 2 responds to an instruction from the IC tag read / write means 112 of the reader / writer 1.
Also, the comparison data register in FIG. 7 stores (stores) the first information 221 and the transmission data register stores the second information 222. Further, the memory stores an IC tag ID, data processed by the signal processing means, and the like.
Further, the first clock generation means in FIG. 7 is a clock that is synchronized with the carrier wave of the IC tag wireless communication means 111, and is a clock that gives a transmission carrier wave and a clock that gives a modulation timing (data transfer rate). Occur. These two clocks are synchronized. The first clock generation means supplies a clock to the parts constituting the reply processing means 212 and the reader / writer wireless communication means 211. Further, the second clock generation means in FIG. 7 is a clock synchronized with the first clock generation means and supplies the clock to the signal processing means in FIG. In general, the frequency of the second clock is made smaller than the frequency of the first clock generating means. As a result, processing that does not need to be processed at high speed can be processed at low speed (appropriate speed). Further, by processing at a low speed, the power consumption per unit time in the IC tag 2 can be reduced.
Further, the power generation means in FIG. 7 supplies power for operating the IC tag 2. The power generation means can be configured to generate power using the carrier wave of the IC tag wireless communication means 111 as a power source. In the configuration shown in FIG. 7, the power consumption per unit time in the IC tag 2 can be reduced by reducing the frequency of the second clock. However, when the generated power is still insufficient, the power generation means A battery can be used (or used together).

In FIG. 7, the operation of the part constituting the reply processing means 115 will be described.
The first second information generating unit 318 generates first information 322 and second information 323. The first and second information setting means 319 outputs a write command to the reader / writer through the reader / writer interface 311. In response, the IC tag read / write unit 112 of the reader / writer writes the first information 322 as the first information 221 in the comparison data register of the IC tag and the second information 323 as the second information 222 in the transmission data register.
The IC tag receiving means receives serially one bit at a time. The received data is serially sent bit by bit to the reception data register. The reception data register is a shift register, and each time 1-bit data is received, the data is serially sent bit by bit from the lower bit to the upper bit. The most significant bit of data is lost due to sequential feed. The comparison means always compares the first information in the comparison data register with all the digits of the data in the reception data register. When the first information and all the digits of the data in the reception data register match, the comparison means outputs a match, that is, a reception end trigger signal.
The reception end trigger signal is used as a transmission start trigger signal, and the second information in the transmission data register is serially transmitted bit by bit through the transmission means (reader / writer wireless communication means 211).
In transmission / reception processing means and reply processing means transmission with hardware configurations as shown in FIG. 6 and FIG. 7, the speed in these processes can be increased, and the delay time and power consumption in those processes can be minimized. For example, it has been described that n data transfer clocks (n = 1, 2, 3,...) Are required from the detection of reception to the start of transmission. can do.

The configuration of the transmission / reception processing unit and the reply processing unit has been described above. Next, the operation in the position information detection system of the present invention will be described. An example of the operation in the position information detection system of the present invention is shown in FIG. 8 as a flowchart.
First, in step S101 (IC tag list display) in FIG. 8, when an operator inputs an instruction to acquire an IC tag ID, the IC tag ID acquisition unit 314 of the position information processing unit 3 reads the reader / writer through a plurality of reader / writers 1. An IC tag ID that identifies each of the IC tags 2 existing in one communication area is acquired. The IC tag ID acquisition unit 314 associates the acquired IC tag ID with the reader / writer ID that identifies the reader / writer 1 that detected it, and stores it in the IC tag information 325.
Next, when the operator inputs an instruction to display the IC tag information 325 in step S102 (designation of the target IC tag), the target IC tag determination means 315 displays the display of the position information processing unit 3 using the IC tag information 324 as a list. (Not shown). The operator designates the IC tag ID of the target whose position information is to be detected from the list. The target IC tag determining means 315 determines the IC tag ID designated and input by the operator as the target IC tag 2 whose position information is to be detected.

Next, when the operator inputs an instruction to display the reader / writer information 325 in step S103 (selection of the target reader / writer), the position information processing unit 3 sets the target IC tag 2 for detecting the position information in the communication area. The reader / writer information 325 of the reader / writer 1 is displayed as a list on the display.
The operator designates a transmission reader / writer from the list. The transmission reader / writer determining means 316 determines the reader / writer of the reader / writer ID designated and input by the operator as the transmission reader / writer that transmits the first information. Note that when the position deriving unit 313 derives the position of the IC tag 2 by the above-described first method for deriving the position, a plurality of reader / writers are determined as transmitting reader / writers. When the position deriving means 313 derives the position of the IC tag 2 by the second position deriving method or the third position deriving method described above, one reader / writer is determined as the transmitting reader / writer.
Further, the operator designates a receiving reader / writer from the list. The receiving reader / writer determining means 317 determines the reader / writer of the reader / writer ID designated and input by the operator as the receiving reader / writer that receives the second information. When the position deriving unit 313 derives the position of the IC tag 2 by the first method for deriving the position, the reader / writer determined as the transmission reader / writer is determined as it is as the reception reader / writer. Further, when the position deriving means 313 derives the position of the IC tag 2 by the second position deriving method or the third position deriving method described above, a plurality of reader / writers are determined as receiving reader / writers. One transmission reader / writer may be included in the plurality of reception reader / writers.
After determining the transmission reader / writer and the reception reader / writer, the operator inputs an instruction for detecting position information.

Next, in step S104 (first second information generation), the first second information generation unit 318 generates a random number as a part of the reader / writer ID and the IC tag ID, or the first information 322 and the first information 322. 2 information 323 is generated.
Next, in step S105 (first second information setting), the first information 322 generated by the first second information generating unit 318 is used as the reader / writer determined as the first reader / writer by the first second information setting unit 319. And set to the target IC tag for detecting position information. In addition, the second information 323 generated by the first second information generation unit 318 is set in the IC tag that is the target to detect the reader / writer and the position information determined as the reception reader / writer by the first second information setting unit 319. . Setting to the IC tag is performed through a reader / writer. The first information 322 set (written) in the transmission reader / writer is the first information 121, and the second information 323 set (written) in the reception reader / writer is the first information 122. The first information 322 set (written) in the target IC tag is the first information 221, and the second information 323 set (written) in the receiving reader / writer is the first information 322. . Note that when the position deriving means 313 derives the position of the IC tag 2 by the first method of position deriving described above, the first information and the first information for one of a plurality of transmitting reader / writers (= receiving reader / writers) are obtained. 2 Set information. When the position deriving means 313 derives the position of the IC tag 2 by the second position deriving method or the third position deriving method described above, it is set for all transmission reader / writers and reception reader / writers.

Next, in step S106 (first information transmission), the IC tag read / write unit 112 of the position information processing unit 3 transmits a transmission start command to the reader / writer determined as the transmission reader / writer. In response to the command, the reader / writer transmits the first information.
Next, in step S107 (transmission time storage), the reader / writer stores (stores) the transmission time.
Next, in step S108 (first information reception), the IC tag receives the first information. At this time, not only the target IC tag but all the IC tags in the communication area have a possibility of receiving.
Next, in step S109 (second information transmission (reply)), only the target IC tag transmits (replies) the second information.
Next, in step S110 (second information reception), the reader / writer receives the second information. At this time, not only the reader / writer determined as the receiving reader / writer but also all reader / writers in the communication area have a possibility of receiving.
Next, in step S111 (reception time storage), only the reader / writer determined as the reception reader / writer stores (stores) the reception time.
When the position deriving unit 313 derives the position of the IC tag 2 by the first position deriving method described above, steps S104 to S111 are repeated for each of the plurality of reader / writers determined as the transmission reader / writer. (See the chain line in FIG. 8). When the position deriving means 313 derives the position of the IC tag 2 by the above-described second method for deriving the position or the third method for deriving the position, the steps are not repeated.

Next, in step S112 (transmission / reception time collection), the position information processing unit 3 collects the transmission time from the reader / writer determined as the transmission reader / writer, collects the transmission time from the reader / writer determined as the transmission reader / writer, The reception time is collected from the reader / writer determined as the reception reader / writer and written in the reader / writer information 324.
Next, in step S113 (distance calculation from the reader / writer), the delay time calculation means 312 of the position information processing unit 3 generates signals generated by the transmission / reception processing means 115 and the reply processing means 212 from the data lengths of the first information and the second information. Calculate the delay time. Further, the position deriving unit 313 of the position information processing unit 3 derives the distance between the IC tag and the reader / writer based on the transmission time, the reception time, the delay time, and the position of the reader / writer.
Next, in step S114 (IC tag position calculation), the position deriving means 313 of the position information processing unit 3 calculates the calculated distance between the IC tag and the reader / writer and the position of the reader / writer obtained by referring to the reader / writer information 324. Based on the above, the position of the IC tag is derived. When the number of reader / writers is three or more, it can be detected as a three-dimensional position.
In the calculation in steps S113 and S114, any one of the first method, the second method, and the third method of position derivation described above can be applied.
Next, in step S115 (IC tag position display), the position information processing unit 3 displays the position of the IC tag on the display. The position is displayed not only as coordinates but also as a position on the floor plan of each floor such as a warehouse or office.

  The present invention can be used in an article inventory management system, a production management system, a personnel movement management system, etc. that perform management for detecting position information of articles, people, and the like.

1 Reader / Writer 111 IC Tag Wireless Communication Unit 112 IC Tag Read / Write Unit 113 Time Management Unit 114 PC Interface 115 Transmission / Reception Processing Unit 121 First Information 122 Second Information 123 Transmission Time 124 Reception Time 125 Reader / Writer ID
2 IC tag 211 Reader / writer wireless communication means 212 Reply processing means 221 First information 222 Second information 223 IC tag ID
3 Position Information Processing Unit 311 Reader / Writer Interface 312 Delay Time Calculation Unit 313 Position Derivation Unit 314 IC Tag ID Acquisition Unit 315 Target IC Tag Determination Unit 316 Transmission Reader / Writer Determination Unit 317 Reception Reader / Writer Determination Unit 318 First Second Information Generation Unit 319 First second information setting means 321 Delay time 322 First information 323 Second information 324 Reader / writer information 325 IC tag information

Claims (12)

A position information detection system including a reader / writer, an IC tag, and a position information processing unit, wherein the reader / writer transmits first information, stores a transmission time, receives second information, and stores a reception time. The IC tag has a reply processing means for receiving the first information and transmitting the second information, and the position information processing unit has the first information and the second information. A delay time calculating means for calculating a delay time of a signal generated by the transmission / reception processing means and the reply processing means from a data length; the IC tag based on the transmission time, the reception time, the delay time, and the position of the reader / writer; A position information detection system comprising position deriving means for deriving the position of the position information. The position information detection system according to claim 1, wherein the first information is a reader / writer ID that identifies a reader / writer that transmits the first information or a part thereof, and the second information is an IC for which position information is detected. A position information detection system characterized by being an IC tag ID for identifying a tag or a part thereof. 3. The position information detection system according to claim 1, wherein the position information processing unit includes a first second information generation unit configured to generate the first information and the second information, the first information, and the second information. A position information detection system comprising first and second information setting means for setting a reader / writer and an IC tag. The position information detection system according to claim 1, wherein the processing by the transmission / reception processing unit and the reply processing unit is performed in synchronization with the transmission carrier wave of the reader / writer. Information detection system. 5. The position information detection system according to claim 1, wherein a clock that is a reference of a clock that gives the transmission time and the reception time in the reader / writer and a clock that generates a transmission carrier wave are the same or synchronized. Position information detection system characterized by 6. The position information detection system according to claim 5, wherein there are a plurality of reader / writers, and the clocks in each of the plurality of reader / writers are the same or synchronized. 7. The position information detection system according to claim 1, wherein the position information processing unit acquires an IC tag ID for identifying each IC tag existing in a communication area of the reader / writer through the reader / writer. A position information detection system comprising: an ID acquisition unit; and the position information processing unit includes a target IC tag determination unit that determines a target IC tag for detecting position information from the acquired IC tag IDs. . 8. The position information detection system according to claim 1, wherein the position information processing unit determines a reader / writer for transmitting the first information from reader / writers connected in communication. A position information detection system comprising: 9. The position information detection system according to claim 1, wherein the position information processing unit is a reader / writer determination unit that determines a reader / writer that receives the second information from among reader / writers that are connected in communication. A position information detection system comprising: 10. The position information detection system according to claim 1, wherein the position deriving unit sets (c × ((reception time−transmission time) −delay time)) / 2 = a, where c is an electromagnetic wave velocity. , It is derived that the IC tag exists in the vicinity of a circle having a radius a centered on the reader / writer as the position, and is obtained by a plurality of reader / writers having different arrangement positions. A position information detection system, wherein, based on a plurality of circles, it is derived that the IC tag exists in the vicinity of an intersection of the plurality of circles as the position. 10. The position information detection system according to claim 1, wherein there is one reader / writer that transmits the first information and stores a transmission time, and receives the second information and stores the reception time. A plurality of reader / writers, wherein the position deriving means sets the distance from the transmitting reader / writer to the IC tag as a, the distance from the IC tag to the receiving reader / writer as b, the electromagnetic wave velocity as c, By calculating (c × ((reception time−transmission time) −delay time)) = a + b = L, the position of the reader / writer to be transmitted and the reader / writer to be received are two focal points as the position, It is derived that the IC tag exists in the vicinity of an ellipse whose sum of distances from the transmitting reader / writer and the receiving reader / writer to the IC tag is constant L (= a + b). Further, based on a plurality of ellipses obtained by the plurality of receiving reader / writers having different arrangement positions, it is derived that the IC tag exists in the vicinity of an intersection of the plurality of ellipses as the position. Position information detection system. 10. The position information detection system according to claim 1, wherein there is one reader / writer that transmits the first information and stores a transmission time, and receives the second information and stores the reception time. The reader / writer is a plurality of readers / writers, and the position deriving means is a distance from the reader / writer to be transmitted to the IC tag, a reception time of the reader / writer to be transmitted is a reception time a, and a reader to be received from the IC tag. Assuming that the distance to the writer is b, the reception time of the receiving reader / writer 1 is the reception time b, and the electromagnetic wave velocity is c, (c × ((reception time b−transmission time) −delay time)) − (c × (( By calculating (reception time a−transmission time) −delay time)) / 2 = (a + b) −a = b, the position is centered on the receiving reader / writer, and the receiving reader / writer receives the I Deriving that the IC tag exists in the vicinity of a circle whose distance to the tag is b, and further, based on a plurality of circles obtained by a plurality of receiving reader / writers having different arrangement positions, as the position, A position information detection system, wherein the IC tag is present near an intersection of a plurality of circles.

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