JP2006145384A - Article position detection apparatus, article position detection method and program thereof - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an article position detecting apparatus capable of specifying the position of an article with an antenna provided in one apparatus with higher accuracy than conventional.
As the article position detection device 1 moves, a radio signal from an article tag is received, and information included in the radio signal is recorded in a database or the like. At the same time, the coordinates of the article position detection device 1 and the time when the coordinates passed are recorded in a database or the like. Further, when weighting correction is performed, a weighting specific process is performed to calculate a weighting value. Then, the number of one or a plurality of wireless signals received from the same article tag, the coordinates of the article position detecting device 1 at each reception time of the radio signals, and the article position detecting device 1 sequentially accepting with movement. The coordinates of the article tag 1 are calculated based on the coordinates and the time when these coordinates are received.
[Selection] Figure 1

Description

  The present invention relates to an article position detection apparatus, an article position detection method, and a program for detecting the position of an article to which an RFID tag is attached.

Conventionally, as a method for managing an article using a small wireless device such as an RFID (Radio Frequency IDentification) tag, techniques described in Patent Documents 1 to 3 are known.
These use a method of confirming the presence or absence of an article by receiving radio waves transmitted from an RFID tag attached to the article using an antenna or a reader.
In recent years, there has been an increasing demand for grasping not only the presence / absence of an article, but also the position where the article exists. Accordingly, methods are used to measure the position of an article by installing antennas throughout the room, or to measure the position of an article by measuring the intensity of radio waves transmitted from an RFID tag with each antenna. ing.

  However, as described above, in the method in which antennas are spread all over the room and an article is in the vicinity of the antenna that can receive the radio wave transmitted from the RFID tag, the antennas that are required as the room becomes wider There is a problem that the number increases and the purchase cost and installation cost of antennas and the like become enormous. In order to solve this problem, there has been known a method of patrol detection in which a radio wave transmitted from an RFID tag is received while the antenna is moved, and the position of the article is specified. Since this is a main element for determining the position where the signal exists, there is a problem in that the accuracy decreases according to the radio wave condition.

Further, Japanese Patent Application No. 2004-187990 has been filed as a technique for identifying the position of an article by receiving radio waves transmitted from an RFID tag while moving the antenna as described above. In this technique, for example, an RFID tag attached to an article and a reference tag that transmits an electric wave that assists in specifying the position of the article are used. However, in this technique, when the reception intensity of the radio wave transmitted from the RFID tag attached to the article and the radio wave transmitted from the reference tag received at almost the same time by the antenna is the same, the position of the antenna is used as a reference. Since it is impossible to accurately read whether the two tags are located in the same direction at the same distance, or whether the two tags are located in different directions with the same distance from the antenna position. An error occurs in the calculation.
JP-A-7-81725 JP 2002-46821 A JP 2002-193448 A

  The present invention has been made in consideration of the above circumstances, and an object of the present invention is to provide an article position detection apparatus and an article that can specify the position of an article with an antenna provided in one apparatus more accurately than in the past. An object is to provide a position detection method and a program thereof.

  In order to achieve the above object, the present invention provides an article identification information transmitting device attached to an article and transmitting the identification information of the article by a wireless signal, and the position of the article by receiving the wireless signal during movement. A position detection apparatus comprising: a position detection apparatus that detects coordinates; and a movement coordinate reception unit that sequentially receives, as the movement, coordinates of the position of the apparatus, the position detection apparatus, and receives the coordinates. The first time detecting means for detecting each time, the second time detecting means for detecting the time when the wireless signal is received, and the coordinates at which the device is located at the time when the wireless signal is received, Signal reception coordinate calculation means for calculating on the basis of the time at which the coordinates are received, the coordinates sequentially received along with the movement, and the times at which the coordinates are received, and the same article identification information Accepts the number of one or a plurality of the radio signals received from the transmission device, the coordinates of the own device at each reception time of the radio signals, the coordinates of the own device that are sequentially accepted with the movement, and the coordinates thereof The article position detecting device, further comprising: transmitter coordinate calculation means for calculating the coordinates of the article identification information transmitter based on the time.

  In addition, the present invention provides the passing point coordinate storage unit that stores the coordinates of the passing points on the moving route in the passing order, and the passing point coordinates each time the article position detection device receives a notification of passing the passing point. Self-coordinate notifying means for sequentially reading the coordinates of the own device stored in the order of passage from the storage means and notifying the moving coordinate accepting means, and the first time detecting means is notified that the passage point has been passed. It is characterized in that the time at which the message is received is detected.

  Further, according to the present invention, the above-described article position detection device includes a plurality of coordinate notification units on the movement route, and further detects the coordinates of the own device based on information obtained from the coordinate notification unit. Self-coordinate detecting means for notifying the moving coordinate receiving means.

  According to the present invention, the above-described article position detection device includes two left and right wheels, a movement distance calculating unit that calculates a movement distance of the left and right wheels based on the number of rotations of the left and right wheels, and the left and right wheels. Direction change angle calculation means for calculating a direction change angle based on the traveling direction of the two wheels at the start of movement based on the respective movement distances, the movement distance of the two wheels, the direction change angle, And a self-coordinate detecting means for detecting coordinates at which the self-device is located at a predetermined time associated with the movement.

  According to the present invention, the above-described article position detection device further includes weight value storage means for storing a weight value corresponding to the reception intensity of the wireless signal, and the transmitter coordinate calculation means transmits the same article identification information transmission. The number of one or a plurality of the radio signals received from the apparatus, the coordinates of the own apparatus at each reception time of the radio signals, the coordinates of the own apparatus that are sequentially received with the movement, and the coordinates are received. Coordinates of the article identification information transmission device are calculated based on the time and the weighting values corresponding to the received reception strengths of the plurality of radio signals.

  The present invention further includes a speed calculation unit that calculates the speed of the own device each time the article position detection device described above sequentially receives coordinates at which the device is positioned in accordance with the movement. Is the number of the plurality of radio signals received from the same article identification information transmitting apparatus, the coordinates of the own apparatus at each reception time of the radio signals, and the coordinates of the own apparatus sequentially received with the movement The coordinates of the article identification information transmitting device are calculated based on the time when the coordinates are received and the calculated weight value of the speed of the device itself.

  Further, the present invention provides the above-described article position detection apparatus, wherein the article identification information transmission apparatus transmits the radio signal with the coordinates of each of the passing points on the moving path within the signal reach of the radio signal. A path density calculation unit that stores each point having a radius centered on each of the passing points, and a path density calculation that calculates, for each passing point that is the center of the circle, a number that overlaps each other circle. Based on each coordinate of its own device at each time at which a plurality of radio signals are received from the same article identification information transmitting device, and a passing point that matches or follows that coordinate is identified and corresponds to that passing point And weighting value calculation means for calculating a reciprocal of the number of circles recorded in the path density storage means as a weighting value, wherein the transmitting device coordinate calculation means includes the same article identification information. The number of the plurality of wireless signals received from the transmission device, the coordinates of the device at each time of reception of the wireless signals, the coordinates of the device received sequentially with the movement, and the time at which the coordinates are received And the coordinates of the article identification information transmitting device are calculated based on the calculated weight value.

  In addition, the present invention provides an article identification information transmitting device attached to an article and transmitting the identification information of the article by a wireless signal, and a position detecting device that receives the wireless signal during movement and detects coordinates where the article is located. The position detection method of the position detection device in an article position detection system comprising: the movement coordinate receiving means of the position detection device sequentially receives the coordinates of the position of the device with the movement, The first time detecting means of the position detecting device detects each time when the coordinates are received, the second time detecting means of the position detecting device detects the time when the wireless signal is received, and the position detecting device The signal reception coordinate calculation means of the position where the device is located at the time when the wireless signal is received, the time when the wireless signal is received, the coordinates received sequentially with the movement, and And the number of one or a plurality of the radio signals received from the same article identification information transmitter by the transmitter coordinate calculation means of the position detection device, and the radio The coordinates of the article identification information transmitting device are calculated based on the coordinates of the device at each time of signal reception, the coordinates of the device that are sequentially received with the movement, and the time at which the coordinates are received. This is an article position detection method.

  In addition, the present invention provides an article identification information transmitting device attached to an article and transmitting the identification information of the article by a wireless signal, and a position detecting device that receives the wireless signal during movement and detects coordinates where the article is located. In the article position detection system comprising: a program executed by a computer of the position detection device, wherein the coordinates of the position of the own device are sequentially received along with the movement, and the coordinates are received. A first time detection process for detecting each time, a second time detection process for detecting the time when the radio signal is received, a coordinate at which the device is located at the time when the radio signal is received, and the radio signal The signal reception coordinate calculation process for calculating based on the received time, the coordinates sequentially received with the movement, and the time at which the coordinates are received, The number of one or a plurality of the radio signals received from the article identification information transmitting device, the coordinates of the own device at each reception time of the radio signals, the coordinates of the own device that are sequentially accepted with the movement, and those This is a program for causing a computer to execute a transmitter coordinate calculation process for calculating the coordinates of the article identification information transmitter based on the time at which the coordinates are received.

According to the present invention, as the position detection device moves, a radio signal is received from the article identification information transmission device, and information included in the radio signal is recorded in a database or the like. At the same time, the coordinates of the position detection device and the time when the coordinates passed are recorded in a database or the like. Further, when weighting correction is performed, a weighting specific process is performed to calculate a weighting value. And the transmission device coordinate calculation means, the number of one or a plurality of radio signals received from the same article identification information transmission device, the coordinates of the own device at each reception time of the radio signals, and the movement The coordinates of the article identification information transmitting device are calculated based on the coordinates of the own device that are sequentially received and the time at which the coordinates are received.
That is, the coordinates of the position detection device that has received the radio signal, the coordinates of the movement route and the time at which the coordinate passes are the main elements, and the coordinates of the article identification information transmission device are calculated. Do not use elements that vary in value, such as finding distances, as main elements. Therefore, the accuracy of coordinate calculation can be further increased.

  Hereinafter, an article position detection apparatus according to an embodiment of the present invention will be described with reference to the drawings. FIG. 1 is a block diagram showing the configuration of the article position detection apparatus according to the present embodiment. In this figure, reference numeral 1 denotes an article position detection device (position detection device). In the article position detection apparatus 1, reference numeral 101 denotes an antenna for receiving a radio signal transmitted from an RFID tag attached to the article. Note that an RFID tag transmits a radio signal, and predetermined information stored in a memory or the like inherent in the RFID tag is held in the radio signal and transmitted by processing of the control unit of the RFID tag. The Hereinafter, an RFID tag attached to an article is referred to as an article tag (article identification information transmission device).

  Reference numeral 102 denotes a signal receiving unit for receiving and processing a radio signal received by the antenna. Reference numeral 103 denotes a movement path detection unit (self-coordinate notification means, self-coordinate detection means, movement distance calculation means, direction change angle calculation means) that detects the movement path of the article position detection apparatus 1. Reference numeral 104 denotes an article tag signal DB (database) for storing information included in a radio signal transmitted from the article tag, its reception time, and the like. Reference numeral 105 denotes a moving path DB (passing point coordinate storage means) that stores the coordinates of each passing point on the moving path. Reference numeral 106 overlaps other circles with respect to the coordinates of the small passing points whose positions are specified at predetermined intervals on the moving path and each circle having a radius (0 <radius) around each small passing point. It is a weighting DB (passing point coordinate storage means) that stores numbers and the like. Reference numeral 107 denotes an article tag position DB that stores coordinates corresponding to each tag ID of the article tag. Reference numeral 108 denotes an article information DB that stores the name of the article to which the article tag is attached and the information of the owner (article attribute information).

  Reference numeral 109 denotes an article tag signal recording unit (second time detection means) that records information included in a radio signal received from the article tag in the article tag signal DB 104. Reference numeral 110 denotes a movement path recording unit (movement coordinate reception means, first time detection means, speed calculation means) that records information on the movement path of the article position detection apparatus 1 in the movement path DB 105. Reference numeral 111 denotes a weight calculation unit (path density calculation means, weight value calculation means) for calculating weight values. The details of weighting are dictated. Reference numeral 112 denotes an article tag position calculation unit (signal reception coordinate calculation means, transmitter coordinate calculation means) that calculates the position of the article tag. Reference numeral 113 denotes a display processing unit that displays information on an article to which an article tag whose position has been calculated is attached on a display unit such as a monitor.

  Then, the article position detection device 1 calculates the coordinates of the article tag using one or a plurality of radio signals received from the same article tag and the coordinates of the own apparatus at each reception time of the radio signals. Perform the process. In the present embodiment, the article position detection apparatus 1 is described as including all the processing units and DBs illustrated in FIG. 1. For example, the antenna 101, the signal reception unit 102, and the movement path detection unit 103 are described. An apparatus (path moving apparatus) including the article tag signal recording unit 109, the movement path recording unit 110, the weight calculation unit 111, the item tag position calculation unit 112, and the display processing unit 113, and a server 104. It is also possible to have a configuration in which each of the devices or servers is connected by a communication network.

FIG. 2 shows the data structure of the movement route DB.
As shown in FIG. 2, the movement path DB stores, for each passing point, the coordinates of the passing point (X coordinate, Y coordinate), the passing time of the point, and the section speed between adjacent passing points. .

<Moving path detection process 1>
FIG. 3 is a diagram showing an outline of a first process for detecting the movement path of the article position detection apparatus.
Next, the process in which the movement path | route detection part 103 detects the movement path | route of the article position detection apparatus 1 is demonstrated using FIG. 2, FIG.
As shown in FIG. 3, first, in the first stage, since the coordinates of each passing point are known in advance, the coordinates (X coordinate, Y coordinate) of the passing point are recorded in the movement path DB 105. However, “Null” data is recorded as information on the passage time and section speed in the travel route DB 105. Then, when the user holds the article position detection device 1 and moves on the movement route, at each passing point, input that the user has passed the passing point (for example, using each input device such as a button). To enter). Then, the movement path detection unit 103 receives information indicating that the vehicle has passed. The movement path detection unit 103 notifies the movement path recording unit 110 of the information. The movement path recording unit 110 sequentially receives information indicating that the passage point has passed from the movement path detection unit 103 as the movement of the movement path of the article position detection device 1 and records the times in the order of the passage points. I will do it. Further, the movement route recording unit 110 calculates a section speed during movement from the previous passage point based on the passage time of each passage point recorded in the movement route DB 105, and records it for each passage point. As a result, the article position detection device 1 receives information about passage of passage points by pressing a button of the user, detects that the passage points have been sequentially passed, and passes the passage time of each passage point. The section speed between the passing points can be detected.

<Movement path detection process 2>
FIG. 4 is a diagram showing an outline of a second process for detecting the movement path of the article position detection apparatus.
Next, a process in which the movement path detection unit 103 detects the movement path of the article position detection apparatus 1 will be described with reference to FIGS. 2 and 4.
In this example, as shown in FIG. 4, a reference tag (coordinate notifying means) is provided on the movement route, and a bar code (coordinate notifying means) is written. Here, the reference tag is constituted by an RFID tag, and the movement path detection unit 103 receives a radio signal transmitted from the reference tag and reads the ID of the reference tag held in the radio signal. The movement path detection unit 103 includes, for example, a reference tag DB in which each reference tag ID and its coordinates are stored in advance, and the reference tag DB is associated with the reference tag ID read from the radio signal. Read the recorded coordinates. Then, the movement path detection unit 103 notifies the movement path recording unit 110 of the coordinates of the reference tag. The movement path recording unit 110 sequentially records the received coordinates in the movement path DB 105. That is, the passing point held by the movement route DB 105 corresponds to the position of each reference tag (Null information is recorded in the movement route DB 105 before the coordinates of the reference tag are recorded). Then, the movement route recording unit 110 calculates the section speed during movement from the previous passage point based on the passage time of each passage point recorded in the movement route DB 105 and records it for each passage point. Thereby, the article position detection device 1 detects that the passage point (that is, on the reference tag) is sequentially passed based on the reception of the wireless signal sequentially transmitted from the reference tag as it moves along the movement route, Moreover, the passage time of each passage point and the section speed between passage points can be detected. If a barcode is written on the movement route instead of the reference tag, the movement route detection unit 103 reads the barcode and detects a unique ID of the barcode from the barcode. The coordinates corresponding to the ID are read from the correspondence table such as the reference tag DB, and the coordinates are notified to the movement path recording unit 110.

<Movement path detection process 3>
FIG. 5 is a diagram showing an outline of a third process for detecting the movement path of the article position detection apparatus.
Next, a process in which the movement path detection unit 103 detects the movement path of the article position detection apparatus 1 will be described with reference to FIGS. 2 and 5.
In this example, as shown in FIG. 5, it is assumed that the article position detection apparatus 1 is provided with wheels, and the position of the antenna 101 is provided between both wheels. Here, when the user inputs the positions of the left wheel and the right wheel immediately before the start of movement, the information is received by the movement path detection unit 103 and recorded in the current position DB held by the movement path detection unit 103 confidence. As shown in FIG. 5, the current position DB stores the coordinates (X coordinate, Y coordinate) of the left wheel, the right wheel, and the antenna at a certain point in time, and an angle (direction change angle) with respect to the traveling direction. Here, the left wheel coordinate (0,0), the right wheel coordinate (10,0), the antenna coordinate (5,0), and the angle are set to 0 degrees. Assume that the right wheel has traveled a distance of R = 10. Then, the left wheel coordinates (0, 20), the right wheel coordinates (10, 10), and the antenna coordinates (5, 10) are obtained. Since these coordinates and the distance W between both wheels are W = 10, the angle with respect to the traveling direction of the article position detection apparatus 1 after the predetermined time has elapsed can be calculated by tan θ = (LR) / W. Note that the angle with respect to the traveling direction of the article position detection apparatus 1 after the predetermined time has elapsed is tan θ = (20−10) / 10 = 1, so θ is 45 degrees. The shorter the predetermined time, the more accurately the position of the article position detection device 1 is recorded in the current position DB. Note that the current position DB is the coordinates (X coordinate, Y coordinate) of the left wheel, the right wheel, and the antenna, and the angle with respect to the traveling direction (direction change angle) at each predetermined time in the movement of the article position detection device 1. Will be updated.

  Then, the movement path detection unit 103 notifies the movement path recording unit 110 of the coordinates of the current position every predetermined time. The movement path recording unit 110 sequentially records the received coordinates in the movement path DB 105. That is, the passing points held by the movement route DB 105 are points for each predetermined time. Then, the movement route recording unit 110 calculates the section speed during movement from the previous passage point based on the passage time of each passage point recorded in the movement route DB 105 and records it for each passage point. Thereby, the article position detection device 1 detects a passing point (that is, on the reference tag) according to the distance traveled along the moving path, that is, the number of rotations of the wheel, and the passing time of each passing point or between the passing points. Can be detected.

<Movement path detection process 4>
In addition to the above processing, for example, when the movement path is determined in advance and the article position detection apparatus 1 moves in a constant speed motion, the movement path detection unit 103 causes the article position detection apparatus 1 according to the movement time. The coordinates of are calculated.

FIG. 6 shows the data structure of the article tag signal DB.
As shown in FIG. 6, the article tag signal DB 104 is associated with the tag ID, the reception intensity (antenna A, antenna B) of the radio signal including the tag ID, and the time when the tag ID is read from the radio signal. The coordinates (X coordinate, Y coordinate) of the article tag corresponding to the tag ID and the weighting value are stored.

FIG. 7 shows the data structure of the article tag position DB.
As shown in FIG. 7, the article tag position DB 107 stores the coordinates (X coordinate, Y coordinate) of the article tag of the tag ID in association with the tag ID. In the article tag position DB 107, the article position detection apparatus 1 receives a radio signal from the article tag, and the coordinates are calculated and sequentially recorded.

FIG. 8 is a diagram showing an outline of the first processing when calculating the coordinates of the article tag.
Next, a first process when the article position detection apparatus calculates the coordinates of the article tag will be described with reference to FIGS. 2, 6, 7, and 8.
Simultaneously with the movement path detection process as described above, the article position detection apparatus 1 receives a radio signal transmitted from the article tag as the movement path moves. The radio signal is received by the antenna 101, and the signal receiving unit 102 notifies the article tag signal recording unit 109 of information (tag ID) included in the radio signal. In addition, the signal receiving unit 102 detects the reception intensity of the received radio signal and notifies the article tag signal recording unit 109 of the reception strength. Here, for example, when the two antennas 101 are provided in the article position detection apparatus 1, the signal receiving unit 102 notifies the reception intensity when receiving by each antenna 101. When the article tag signal recording unit 109 receives the transfer of various information from the signal receiving unit 102, the tag ID, the reception strength of the antenna, the time when the tag ID is received (that is, the time when the tag ID is read from the radio signal), Are recorded in the article tag signal DB. At this time, the coordinates of the article tag corresponding to the tag ID are unconfirmed. The weight is set to 1.

  Then, when information is recorded in the article tag signal DB 104, the article tag position calculation unit 112 starts calculating the coordinates of the article tag indicated by the tag ID. First, the article tag position calculation unit 112 reads the tag ID “001” and the information of the reading time “10:00:04” recorded corresponding to the ID from the article tag signal DB 104. Here, when the time “10:00:04” at which the tag ID “001” is read is the same as the passage time of the passage point, the article tag position calculation unit 112 determines that the coordinates of the tag ID “001” are Assuming that the coordinates are the same as the coordinates of the passing point, the coordinates are recorded in association with the tag ID “001” of the article tag signal DB 104. Similarly, the coordinates are recorded in the article tag position DB 107 in association with the tag ID “001”.

  In addition, when the time “10:00:04” at which the tag ID “001” is read is not the same as the passage time of the passing point, the article tag position calculation unit 112 reads the time before and after the read time. The coordinates (X coordinate, Y coordinate) of the two passing points recorded in the movement route DB 105 in association with the time are read. And

The coordinates of the tag ID “001” are calculated by the following formula. From FIG. 8, the coordinates of the tag ID “001” are (X coordinate, Y coordinate) = (10, 26). As described above, the coordinates are associated with the tag ID “001” and recorded in the article tag signal DB 104 and the article tag position DB 107.

FIG. 9 is a diagram showing an outline of the second processing when calculating the coordinates of the article tag.
Next, a second process when the article position detection apparatus calculates the coordinates of the article tag will be described with reference to FIG.
As shown in FIG. 9, when a radio signal is received from a single article tag a plurality of times, different coordinates are recorded in the article tag signal DB 104 in association with the same tag ID by the above processing. It becomes. In this case, the article tag position calculation unit 112

More detailed coordinates are calculated using the above formula, and the calculated coordinates are recorded in the article tag signal DB 104 and the article tag position DB 107 in association with the tag ID. By this process, as shown by a and b in FIG. 9, coordinates of equidistance from the coordinates of the three points that received the wireless signal are calculated, so that the coordinates of the article tag can be calculated in more detail. it can.

FIG. 10 is a first diagram illustrating an outline of processing for specifying a weighting value.
Next, a first process for specifying a weighting value will be described with reference to FIG.
FIG. 10c shows a weighting specification table that holds weighting values corresponding to combinations of reception strengths of two antennas. Then, as processing before the article tag position calculation unit 112 calculates the coordinates of the article tag, the weight calculation unit 111 associates an antenna reception intensity of the two antennas recorded in the article tag signal DB 104 with being associated with a certain tag ID. , And the weight value recorded in the weight identification table c in correspondence with the two antenna reception strengths is read. The read weight value is recorded in the article tag signal DB 104. Thereby, in the above-described processing in which the article tag position calculation unit 112 calculates the coordinates of the article tag using the formula (2), the weighting value specified by the weighting calculation unit 111 is used. As a result, the coordinates of the article tag are calculated even in accordance with the reception intensity, so that the coordinates can be calculated with higher accuracy. The data of the weight value specification table c shown in FIG. 10 is recorded in a memory (weight value storage means) or the like, and the weight calculation unit 111 reads the data to specify the weight value. In the weighting specification table c, it is assumed that the value of the radio wave intensity increases as the distance from the tag is shorter. Also, the weighting specification table c is an example in the case of two antennas, but weighting is possible in the same way even with one antenna.

FIG. 11 is a second diagram illustrating an outline of processing for specifying a weighting value.
Next, a second process for specifying a weight value will be described with reference to FIG.
As shown by <A> in FIG. 11, when the article position detection device 1 moves at a different speed within the range of the reach of the radio signal transmitted from an article tag, the route moved slowly within the range ( In a2), many radio signals are received from the article tag, and in the route (a1) that has moved quickly within the range, reception of radio signals from the article tag is reduced. Therefore, when the coordinates are calculated by the method for calculating the coordinates of the article tag shown in FIG. 9, as shown by <B> in FIG. 11, coordinates close to the slowly moving route are calculated. Therefore, when calculating the weight value of an article tag with a certain tag ID, the weight calculation unit 111 first reads the reading time associated with the certain tag ID and recorded in the article tag signal DB 104, and the time The section speed recorded in the movement route DB 105 is read in association with the passing point that has passed. Then, the section speed is recorded in the article tag signal DB 104 as a weighting value. As a result, the weighting value calculated by the weighting calculation unit 111 is used in the processing of FIG. 9 in which the item tag position calculation unit 112 calculates the coordinates of the item tag using Expression (2). Therefore, in the coordinate calculation process of FIG. 9, the number of times of reception of the radio signal according to the section speed is taken into account, and the weight for the route with a higher section speed is greater than the weight for the path with a lower section speed. Control can be performed so that the coordinates of the tag do not approach a route with a slow section speed within the reach of the radio signal transmitted by the tag.

FIG. 12 is a diagram illustrating an example of a problem when specifying a weighting value.
Next, an example of a problem when specifying a weighting value will be described with reference to FIG.
As shown by <C> in FIG. 12, when the article position detection device 1 moves along an eight-character movement path within the reach of a radio signal transmitted from a certain article tag, the article is within the range where the movement paths overlap. The number of receptions of radio signals transmitted from the tag increases. In this case, as shown by <C>, the article tag is actually located in the middle of the reachable range, but in the range where the travel routes overlap, the number of receptions of the radio signal transmitted from the article tag is equal to the reachable range. Since there are more than the other ranges, the coordinates of the article tag calculated by the processing of the article tag position calculation unit 112 in FIG. 9 are inclined to the range in which many radio signals are received.

  In addition, as shown by <D> in FIG. 12, when there is a movement path in a deviated range within the reach of a radio signal transmitted from a certain article tag, and the article position detection apparatus 1 moves along the movement path, The position detection device 1 receives a large number of radio signals in a range in which there are many moving paths within the reachable range. Therefore, as shown in <D>, the article tag is actually located in the middle of the reachable range, but the radio signal transmitted from the article tag is received in a range where there are many moving routes within the reachable range. Since the number of times of the operation is large, the coordinates of the article tag calculated by the processing of the article tag position calculation unit 112 in FIG. 9 are inclined to a range where there are many movement paths. Therefore, the problem as seen in the examples <C> and <D> in FIG. 12 must be solved.

FIG. 13 is a diagram 3-1 showing an outline of the process for specifying the weighting value.
FIG. 14 is a diagram 2-2 showing an outline of the process of specifying the weighting value.
FIG. 15 shows the data structure of the weighting DB.
As shown in FIG. 15, the weighting DB 106, for each small passage point, the coordinates of the small passage point (X coordinate, Y coordinate), the passage time of the point, a circle centered on the point, and other passages The number of overlapping circles around the point is stored as a count.

Next, a third process for specifying a weighting value for solving the problem shown in FIG. 12 will be described with reference to FIGS.
First, the article position detection apparatus 1 stores a circle setting table as shown in FIG. Further, the coordinates of the small passing points as shown by <E> in FIG. The coordinates of the small passage points may be points that are known in advance on the movement route, or the small passage points are calculated at the same time when the movement route calculation unit 103 calculates each passage point of the movement route. You may do it. At that time, a small passing point on the moving route corresponding to the small section distance shown in the circle setting table d is calculated.

First, the weighting calculation unit 111 reads the coordinates of the small passage points with reference to the weighting DB 106. Based on the relationship between the coordinates of one small passage point and the coordinates of the other small passage point, a circle centered on the coordinates of the one small passage point is centered on the coordinates of the other small passage point. Calculate the number of overlapping circles. That is, assuming that the radius of a circle is Z, the coordinates of one small passage point are (x1, y1), and the coordinates of the other small passage points are (x2, y2), {(x2-x1) ² + (y2− It is only necessary to calculate the number of two other small passing points that satisfy y1) ² } ^1/2 ≦ Z. Then, the weighting calculation unit 111 records the number of overlapping circles in the weighting DB 106 in association with the number of small section points.

  Next, from FIG. 14, the weight calculation unit 111 reads the reading time recorded in the article tag signal DB 104 in association with a certain tag ID, and associates with the small passage point that has passed at that time in the weighting DB 106. Read the recorded count value (the number of overlapping circles). Then, the reciprocal of the count value is recorded in the article tag signal DB 104 as a weighting value of the certain tag ID. In addition, when the reading time recorded in the article tag signal DB 104 associated with a certain tag ID is read and the reading time is a time between two small passing points, the two times Two count values (the number of overlapping circles) recorded in the weighting DB 106 in association with the small passage points are read. Then, the average reciprocal of the read count is recorded in the article tag signal DB 104 as a weight value of the certain tag ID. In the process of FIG. 9 in which the article tag position calculation unit 112 calculates the coordinates of the article tag, the weighting value specified by the weighting calculation unit 111 is used. In other words, with the processing of FIG. 9 alone, as shown in FIG. 12, the article tag is calculated to be tilted to a range where there are more movement paths than the original coordinates, but received within the range where there are many movement paths. Since the weighting to the radio signal of the article tag is reduced by the reciprocal, the coordinates of the article tag can be calculated with higher accuracy.

FIG. 16 shows the data structure of the article information DB.
As shown in FIG. 16, the article information DB stores article attribute information such as an article name and an owner in association with the article tag ID.
FIG. 17 is a diagram illustrating a processing flow of the article position detection apparatus 1.
Next, the overall flow of processing of the article position detection apparatus 1 will be described with reference to FIG.
First, the tag ID of an article tag is recorded in advance in the article tag position DB 107 (step S1). At this time, the coordinates of each article tag are undefined. Then, as the article position detection device 1 moves, a radio signal is received from the article tag, and information included in the radio signal is recorded in the article tag signal DB 104 (step S2). At the same time, the movement path detection unit 103 records the coordinates of the article position detection device 1 and the time when the movement passes through the movement path DB (step S3). When performing weight correction, the weight calculation unit 111 performs specific weighting processing and rewrites the weight value recorded in the article tag signal DB 104 (step S4). Then, the article tag position calculation unit 112 calculates the coordinates of each article tag based on the article tag signal DB 104 and information recorded in the movement route DB 105, and records the coordinates in the article tag position DB 107 (step S5). Further, the display processing unit 113 displays details of each article and information on where the article is located (that is, coordinates) on a monitor or the like based on the tag IDs recorded in the article tag position DB 107 and the article information DB 108. (Step S6).

  The above-described article position detection apparatus has a computer system inside. The process described above is stored in a computer-readable recording medium in the form of a program, and the above process is performed by the computer reading and executing this program. Here, the computer-readable recording medium means a magnetic disk, a magneto-optical disk, a CD-ROM, a DVD-ROM, a semiconductor memory, or the like. Alternatively, the computer program may be distributed to the computer via a communication line, and the computer that has received the distribution may execute the program.

  The program may be for realizing a part of the functions described above. Furthermore, what can implement | achieve the function mentioned above in combination with the program already recorded on the computer system, and what is called a difference file (difference program) may be sufficient.

It is a block diagram which shows the structure of the article position detection apparatus by this embodiment. It is a figure which shows the data structure of movement route DB by this embodiment. It is a figure which shows the outline | summary of the 1st process which detects the movement path | route of the article | item position detection apparatus by this embodiment. It is a figure which shows the outline | summary of the 2nd process which detects the movement path | route of the article | item position detection apparatus by this embodiment. It is a figure which shows the outline | summary of the 3rd process which detects the movement path | route of the article | item position detection apparatus by this embodiment. It is a figure which shows the data structure of article | item tag signal DB by this embodiment. It is a figure which shows the data structure of goods tag position DB by this embodiment. It is a figure which shows the outline | summary of the 1st process at the time of calculating the coordinate of the article tag by this embodiment. It is a figure which shows the outline | summary of the 2nd process at the time of calculating the coordinate of the article tag by this embodiment. It is a 1st figure which shows the outline | summary of the process which specifies the weighting value by this embodiment. It is a 2nd figure which shows the outline | summary of the process which specifies the weighting value by this embodiment. It is a figure which shows the example which becomes a problem when specifying the weighting value by this embodiment. It is a figure of 3-1 which shows the outline | summary of the process which specifies the weighting value by this embodiment. It is a 3-2 figure which shows the outline | summary of the process which specifies the weighting value by this embodiment. It is a figure which shows the data structure of weighting DB by this embodiment. It is a figure which shows the data structure of article information DB by this embodiment. It is a figure which shows the processing flow of the article position detection apparatus 1 by this embodiment.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Article position detection apparatus 101 ... Antenna 102 ... Signal receiving part 103 ... Moving path detection part 104 ... Article tag signal DB
105 ... travel route DB
106 ... Weighting DB
107 ... article tag position DB
108 ... Article information DB
DESCRIPTION OF SYMBOLS 109 ... Article tag signal recording part 110 ... Movement path recording part 111 ... Weighting calculation part 112 ... Article tag position calculation part 113 ... Display processing part

Claims (9)

An article identification information transmitting device attached to the article and transmitting the identification information of the article by a wireless signal;
A position detection device that receives the wireless signal during movement and detects the coordinates of the article;
In the article position detection system comprising:
Moving coordinate receiving means for sequentially receiving the coordinates of the own device along with the movement;
First time detecting means for detecting respective times at which the coordinates are received;
Second time detecting means for detecting a time when the wireless signal is received;
A signal that is calculated based on the coordinates at which the device is located at the time when the wireless signal is received, the time at which the wireless signal is received, the coordinates that are sequentially received along with the movement, and the time at which the coordinates are received. Received coordinate calculation means;
The number of one or a plurality of the radio signals received from the same article identification information transmitting device, the coordinates of the own device at each time of reception of the radio signals, and each of the own devices sequentially received with the movement Transmitting device coordinate calculating means for calculating coordinates of the article identification information transmitting device based on the coordinates and the time at which the coordinates were received;
An article position detecting device comprising: Passing point coordinate storage means for storing the coordinates of each passing point on the moving route in the order of passage;
Self-coordinate notifying means for sequentially reading the coordinates of the own device stored in the order of passage from the passing point coordinate storage means and notifying the moving coordinate acceptance means every time a notification of passing the passing point is received;
With
The article position detection device according to claim 1, wherein the first time detection unit detects a time at which a notification of passing through the passage point is received. A plurality of coordinate notification means are provided on the moving route,
further,
Self-coordinate detecting means for detecting the coordinates of the own device based on the information obtained from the coordinate notifying means and notifying the moving coordinate receiving means;
The article position detection apparatus according to claim 1, comprising: Two wheels on the left and right,
A moving distance calculating means for calculating a moving distance of the left and right wheels based on the number of rotations of the left and right wheels;
A direction change angle calculation means for calculating a direction change angle based on the traveling direction of the two wheels at the start of movement based on the moving distance of each of the left and right wheels;
Self-coordinate detection means for detecting the coordinates of the self-device at a predetermined time associated with the movement, based on the movement distance of the two wheels and the direction change angle;
The article position detection apparatus according to claim 1, comprising: Further comprising weight value storage means for storing a weight value corresponding to the reception intensity of the radio signal;
The transmitter coordinate calculation means is
The number of one or a plurality of the radio signals received from the same article identification information transmitting device, the coordinates of the own device at each time of reception of the radio signals, and each of the own devices sequentially received with the movement The coordinates of the article identification information transmitting device are calculated based on the coordinates and the time when the coordinates are received, and the weighting values corresponding to the received strengths of the plurality of received radio signals. The article position detection device according to any one of claims 1 to 4. A speed calculating means for calculating the speed of the own apparatus every time the coordinates of the own apparatus are sequentially received with the movement,
The transmitter coordinate calculation means is
The number of the plurality of wireless signals received from the same article identification information transmitting device, the coordinates of the device at each time of reception of the wireless signals, the coordinates of the device received sequentially with the movement, and those 5. The coordinates of the article identification information transmitting device are calculated based on the time at which the coordinates are received and a weighted value of the calculated speed value of the own device. Article position detection apparatus. Passing point coordinate storage means for storing the coordinates of each of the equally spaced passing points on the moving path within the signal reach of the wireless signal for each of the article identification information transmitting devices that transmit the wireless signal;
For each circle having a radius centered on each of the passing points, a path density calculating means for calculating the number overlapping with other circles for each passing point that is the center of the circle,
Based on each coordinate of its own device at each time at which a plurality of the radio signals are received from the same article identification information transmitting device, a passing point that coincides with or before or after that coordinate is specified, and corresponding to the passing point, A weight value calculating means for calculating a reciprocal of the number of circles recorded in the path density storage means as a weight value;
The transmitter coordinate calculation means is
The number of the plurality of wireless signals received from the same article identification information transmitting device, the coordinates of the device at each time of reception of the wireless signals, the coordinates of the device received sequentially with the movement, and those The article position detection apparatus according to any one of claims 1 to 4, wherein coordinates of the article identification information transmitting apparatus are calculated based on the time at which coordinates are received and the calculated weighting value. An article identification information transmitting device attached to the article and transmitting the identification information of the article by a wireless signal;
A position detection device that receives the wireless signal during movement and detects the coordinates of the article;
A position detection method of the position detection device in an article position detection system comprising:
The movement coordinate receiving means of the position detection device sequentially receives the coordinates where the device is located along with the movement,
The first time detection means of the position detection device detects each time when the coordinates are received,
The second time detecting means of the position detecting device detects the time when the wireless signal is received;
The signal reception coordinate calculation means of the position detection device receives the coordinates where the device is located at the time when the wireless signal is received, the time when the wireless signal is received, the coordinates received sequentially with the movement, and the coordinates Calculated based on the time when
The transmission device coordinate calculation means of the position detection device receives the number of one or a plurality of the radio signals received from the same article identification information transmission device, and the coordinates of the own device at each reception time of the radio signals. An article position detection method, comprising: calculating coordinates of the article identification information transmitting apparatus based on the coordinates of the own apparatus that are sequentially received with the movement and the time when the coordinates are received. An article identification information transmitting device attached to the article and transmitting the identification information of the article by a wireless signal;
A position detection device that receives the wireless signal during movement and detects the coordinates of the article;
In the article position detection system comprising: a program to be executed by a computer of the position detection device,
A movement coordinate reception process for sequentially receiving the coordinates of the own device along with the movement;
A first time detection process for detecting each time at which the coordinates are received;
A second time detection process for detecting a time at which the wireless signal is received;
A signal that is calculated based on the coordinates at which the device is located at the time when the wireless signal is received, the time at which the wireless signal is received, the coordinates that are sequentially received along with the movement, and the time at which the coordinates are received. Receive coordinate calculation processing,
The number of one or a plurality of the radio signals received from the same article identification information transmitting device, the coordinates of the own device at each time of reception of the radio signals, and each of the own devices sequentially received with the movement A transmission device coordinate calculation process for calculating coordinates of the article identification information transmission device based on the coordinates and the time at which the coordinates were received;
A program that causes a computer to execute.

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