JP2009047583A - Object search device, object search system and wireless communication terminal - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an object search system capable of revealing where a search object is at present, without previously registering positional information of the search object, for example an article, organism, human being. <P>SOLUTION: This object search system is provided with an object search device for searching a search object and a wireless tag attached to the search object. The object search device comprises a wireless communication means for communicating with the wireless tag; a means for measuring the distance to the wireless tag, based on the wave information during transmission/reception with the wireless tag; a means for acquiring the positional information of the measurement position where the distance is measured; a means for estimating the position of the search object, based on the distance and the positional information, when the distance is measured at two or more different measurement positions; and an output means for outputting the information for the position inferred. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to an object search device, an object search system, and a wireless communication terminal, and can be applied to search for articles used in daily life and business, for example.

A system that searches for places where people do not know where they have gone, such as TV remotes, pens, calculators, tissue boxes, etc. As an example, there is an information processing apparatus described in Patent Document 1.
JP-A-10-198731

  However, in the information processing apparatus described in Patent Document 1, when a wireless tag having a predetermined ID (identification information) is placed in a specific location in advance, information on a position linked to the ID is obtained from the object search apparatus (terminal side). Or it had to be stored in a server connected via a network.

  Therefore, an object search device and object search that can clarify where the search target object is currently without registering position information of the search target object (for example, articles, organisms, humans, etc.) in advance. Systems and wireless communication terminals are desired.

  An object search device according to a first aspect of the present invention includes: (1) an object search device that searches for a search target object; (2) a wireless communication unit that communicates with a wireless tag attached to the search target object; A distance measuring means for measuring a distance between the object search device and the wireless tag based on radio wave information when the wireless communication means transmits and receives radio waves to and from the wireless tag; and (4) the distance. And (5) the distance measurement unit measures the distance at two or more different measurement positions by the measurement unit that acquires the position information of the measurement position. Position estimation means for estimating the position of the search target object based on the distance and position information of the measurement position; and (6) information on the position of the search target object estimated by the positional relationship estimation means. Output And an outputting unit that.

  The object search device according to the second aspect of the present invention includes: (1) an antenna that can be directed in a plurality of different directions; and (2) communication with a wireless tag attached to the search target object via the antenna. And (3) direction measuring means for measuring the direction in which the antenna transmits or receives radio waves when the wireless communication means communicates with the wireless tag, and (4) the direction measuring means It has a positional relationship estimation unit that estimates that the search target object exists in the measured direction, and (5) an output unit that outputs information on the direction estimated by the positional relationship estimation unit.

  A wireless communication terminal according to a third aspect of the present invention includes the object search device according to the first or second aspect of the present invention.

  An object search system according to a fourth aspect of the present invention includes (1) the object search device according to the first or second aspect of the present invention, and (2) a wireless tag attached to the search target object.

  According to the present invention, there is provided an object search system for clarifying where a search target object is currently located without previously registering position information of the search target object (for example, an article, a living thing, a human being, etc.). be able to.

(A) First Embodiment Hereinafter, a first embodiment of an object search device and an object search system according to the present invention will be described in detail with reference to the drawings.

(A-1) Configuration of the First Embodiment FIG. 1 is a block diagram showing the overall configuration of the object search system of this embodiment.

  The object search system 100 includes an object search device 110 and a wireless tag 120.

  The wireless tag 120 is a tag that can exchange information with the object search device 110 by wireless communication. For example, an RFID tag using RFID (Radio Frequency IDentification) is applicable. The wireless tag 120 is attached to a search target article 130 that is a search target article in the object search system. Examples of articles to be searched include articles that do not know where a person has gone, such as TV remote controllers, pens, calculators, tissue boxes, etc. that are carried around in daily life or business. Further, the search target is not limited to an article, and may be a human being, an organism such as an animal or a plant, and the type of the object is not limited as long as it is any object.

  For example, when the search target is a human, the wireless tag 120 may be carried in a pocket or the like, or when the search target is an animal such as a dog, The method of attaching the wireless tag to the search target is not limited as long as the position of the search target matches the position of the wireless tag.

  Further, in FIG. 1 described above, only one wireless tag 120 and search target article 130 are shown, but a plurality of them may be arranged. Each wireless tag 120 may have identification information such as ID information, and may respond with the above-described ID information when requested by the object search device 110 through wireless communication.

  The object search device 110 communicates with the wireless tag 120 attached to the search target article 130, estimates the position of the wireless tag 120, and further estimates that the search target article 130 exists at the same position as the wireless tag 120. Information on the position is output.

  The object search device 110 includes a control unit 111, a position measurement unit 112, a wireless communication unit 113, an antenna 114, a position estimation unit 115, an input unit 116, an output unit 117, and an article information storage unit 118.

  The object search device 110 is a device having an interface for communicating with a wireless tag (such as a CPU, a ROM, a RAM, an EEPROM, a hard disk, etc.) It may be obtained by installing a search program or the like, but it can be functionally shown as in FIG. 1 described above.

  The control unit 111 controls the operation of each unit in the object search device 110.

  The position measurement unit 112 measures the position of the object search device 110. For example, the position measurement unit 112 includes an acceleration sensor and measures the position of the object search device 110. The position measurement unit 112 provides information regarding the position of the object search device 110 to the position estimation unit 14 via the control unit 111. As the acceleration sensor included in the position measuring unit 112, an acceleration sensor based on MEMS (Micro Electros Mechanical Systems) may be used. Further, it may be a three-dimensional acceleration sensor or a two-dimensional acceleration sensor.

  The antenna 114 is an antenna that communicates with the wireless tag 120, and may be configured by, for example, an omnidirectional antenna (for example, a monopole antenna) that transmits and receives radio waves in all directions.

  The wireless communication unit 113 communicates with the wireless tag 120 via the antenna 114. Further, the wireless communication unit 113 measures the distance from the object search device 110 to the wireless tag 120 based on radio wave information such as arrival radio wave intensity and arrival radio wave time in transmission / reception of radio waves with the radio tag 120, Information on the measurement result is given to the position estimation unit 14 via the control unit 111.

  Hereinafter, an example of a configuration in which the wireless communication unit 113 (antenna 114) measures the distance to the wireless tag 120 will be described.

  The wireless communication unit 113 transmits a radio wave including a signal requesting a response (for example, a signal requesting a response of ID information) to the wireless tag 120. When the radio wave reaches the wireless tag 120, the wireless tag 120 transmits a response signal (for example, a signal including ID information of the wireless tag 120) to the object searching device 110. At that time, the wireless communication unit 113 records a response time from when a radio wave is transmitted to the wireless tag 120 to when a response radio wave is received, and based on the time during that time, the object search device The distance between the wireless tag 110 and the wireless tag 120 may be measured. For example, the longer the response time, the longer the distance between the object search device 110 and the wireless tag 120 may be determined. Note that the wireless communication unit 113 preferably has the performance that the spatial resolution when measuring the distance to the wireless tag 120 is 30 cm or less, and for that purpose, between the wireless tag 120 and the object search device 110. The wireless communication band in communication is preferably a high frequency band of 1.5 GHz or more and a wide band of 500 MHz or more.

  Further, when the wireless communication unit 113 transmits a radio wave to the wireless tag 120, it transmits a signal including information on the time when the radio wave is transmitted, and the wireless tag 120 responds with the given information as it is. Anyway. Accordingly, the wireless communication unit 113 grasps when the response is made based on the transmitted radio wave according to the content of the response from the radio tag 120, and compares the response radio wave with the time when the radio wave is received. Measure the distance to 120. Alternatively, the wireless communication unit 113 may transmit radio waves to the wireless tag 120 a plurality of times, receive response radio waves, and use the average value of each measurement result as the distance from the wireless tag 120.

  Further, the wireless communication unit 113 may measure the distance from the wireless tag 120 based on the intensity of the response radio wave from the wireless tag 120. For example, the stronger the response radio wave from the wireless tag 120, the shorter the distance from the wireless tag 120 may be determined.

  Further, identification information such as ID information of the wireless tag 120 attached to the search target article 130 to be searched is set in the wireless communication unit 113 in advance, and only the distance of the set ID information to the wireless tag 120 is measured. However, the distance from the wireless tag 120 of other ID information may not be measured. In this case, when the wireless tag 120 responds, a signal including identification information such as ID information of the wireless tag is responded, and the wireless communication unit 113 measures only the distance from the wireless tag 120 of the set ID information. To do. The ID information of the wireless tag 120 set in the wireless communication unit 113 may be set based on information input to the input unit 116 described later.

  As described above, the wireless communication unit 113 measures the distance from the wireless tag 120.

  The position estimation unit 115 estimates the position where the wireless tag 120 exists, that is, the position of the search target article 130 based on information given from the position measurement unit 112 and the wireless communication unit 113.

  FIG. 2 is an explanatory diagram for explaining an example of a method for estimating the position of the wireless tag 120 in the position estimation unit 115.

  As shown in FIG. 2, in the position estimation unit 115, the position where the wireless tag 120 exists is estimated based on the result of measuring the distance to the wireless tag 120 from three or more different measurement positions. You may carry out by surveying. In the position estimation unit 115, the positional relationship between the measurement positions 1, 2, and 3 is grasped using information given from the position measurement unit 112. For example, if the position measurement unit 112 is activated at the measurement position 1 and the measurement positions 2 and 3 and the object search system 100 are moved, the measurement positions 2 and 3 and the current position are set using the measurement position 1 as a reference point. Is grasped. The distance from each measurement position to the wireless tag 120 uses information measured by the wireless communication unit 113 (antenna 114) described above when the object search device 110 is moved to each measurement position. When the position estimation unit 115 estimates the position of the wireless tag 120, the distance between the measurement positions is the spatial resolution when the distance to the wireless tag 120 is measured by the wireless communication unit 113 described above. It is preferable that the distance is more than the distance.

  The article information storage unit 118 is a storage unit that stores information on the search target article 130 to be searched and the wireless tag 120 attached to the search target article 130. In the article information storage unit 118, for example, information such as the name of the search target article 130, image data indicating the entire form, and ID information of the attached wireless tag 120 is stored. As the image data indicating the form of the search target article 130, for example, the object search device 110 may include a unit that captures an image such as a digital camera, and image data captured by the digital camera may be used.

  FIG. 3 is an explanatory diagram illustrating an example of the interface with the user, that is, the input unit 116 and the output unit 117, in the object search device 110.

  The input unit 116 is an interface for reading information from the user in the object search device 110 based on the control of the control unit 111, and may have a button as shown in FIG. A touch panel or the like may be used, and the input means is not limited. However, here, description will be made assuming that the touch panel is shown in FIG. Here, it is assumed that the input unit 116 has buttons such as a search button, a numeric keypad, and a registration button as shown in FIG. 3 described above.

  The output unit 117 is a unit that outputs information to the user in the object search device 110 based on the control of the control unit 111. For example, the output unit 117 may display the output on a display device such as a display as shown in FIG. However, it may be configured to be stored in a storage device such as a disk device, output as audio, or printed out to a printing device such as a printer, and the output method is not limited. Here, the output unit 117 is assumed to display the display as shown in FIG. 3 described above, for example.

  Hereinafter, input / output examples in the input unit 116 and the output unit 117 will be described.

  For example, when the user moves with the object search device 110 and presses the search button of the input unit 116 at each measurement position (see FIG. 3 described above), information on the position at the position is displayed in the position measurement unit. 112 to the position estimation unit 115. In addition, the wireless communication unit 113 measures the distance from the object search device 110 to the wireless tag 120, and gives the information to the position estimation unit 115. When the search button of the input unit 116 is pressed three times or more, the position estimation unit 115 estimates the position of the wireless tag 120 to be searched, and the output unit 117 outputs information.

  Each time the search button of the input unit 116 is pressed by the user, the information on the current position of the object search device 110, the measurement position where the measurement was performed in the past, and the position of the wireless tag 120 to be searched is described above. As shown in FIG. 3, the output of the output unit 117 may be output. For example, as shown in FIG. 3 described above, each measurement position may be displayed with an asterisk. In addition, for example, as shown in FIG. 3 described above, height information at each measurement position may be displayed by a graph such as an error bar. Further, the output unit 117 may display the entire image of the search target article 130 stored in the article information storage unit 118.

  Here, as an example of a method of outputting information related to the position of the wireless tag 120 to the user by the output unit 117, the method using the above-described star or error bar has been described. However, the direction and position are expressed only by numerical values. The output method is not limited as long as the method allows the user to recognize the position of the wireless tag 120 (search target article 130).

  Further, the input unit 116 allows the user to input information related to the search target article 130 to be searched and reads the information, and the control unit 111 specifies ID information of the wireless tag 120 to be searched based on the read information. The specified ID information may be given to the wireless communication unit 113 and set. For example, the image of the search target article 130 stored in the article information storage unit 118 is displayed on the output unit 117, and the image of the search target article 130 to be displayed is switched in response to pressing of the numeric keypad of the input unit 116. The search target article 130 to be searched may be specified. Then, the control unit 111 may acquire the ID information of the wireless tag 120 attached to the search target article 130 specified as the search target based on the information stored in the article information storage unit 118. Further, the ID information of the wireless tag 120 may be directly input by the user to the numeric keypad of the input unit 116 as information related to the search target article 130 and read.

(A-2) Operation of First Embodiment Next, an operation of searching for the search target article 130 (wireless tag 120) in the object search system having the above configuration will be described.

  FIG. 4 is a sequence diagram illustrating a search operation in the object search apparatus according to the first embodiment.

  First, when information related to the search target article 130 to be searched is input by the user using the numeric keypad of the input unit 116, the control unit 111 attaches the information to the search target article 130 to be searched based on the read information. ID information of the obtained wireless tag 120 is acquired. Then, the acquired ID information is given from the control unit 111 to the wireless communication unit 113 (S101, S102).

  Next, when the user presses the search button of the input unit 116, radio waves are transmitted from the wireless communication unit 113 to the surrounding wireless tags 120. Then, based on the response time from the wireless tag 120, the distance between the object search device 110 and the wireless tag 120 is measured, and information on the measured distance is given to the control unit 111 and the position estimation unit 115. . Note that in the wireless communication unit 113, the wireless tag 120 that is the target of distance measurement is only the wireless tag 120 that has the ID information acquired in step S102 described above. Further, the position measuring unit 112 is activated, and measurement of the position of the object search device 110 is started by the acceleration sensor. In addition, the output unit 117 is controlled by the control unit 111, and an asterisk indicating the first measurement position is displayed on the display (S103).

  Next, when the user who has the object search device 110 moves and the search button of the input unit 116 is pressed, the distance to the wireless tag 120 is measured by the wireless communication unit 113 as in step S103 described above. Then, the distance information is provided to the control unit 111 and the position estimation unit 115. In addition, information on the relative position between the first measurement position (the position in step S103 described above) and the current position of the object search device 110 is acquired and provided to the control unit 111 and the position estimation unit 115. Then, the output unit 117 is controlled by the control unit 111, and an asterisk indicating the positional relationship with the second measurement position and an error bar indicating the height are further displayed on the display (S104).

  Next, when the user who has the object search device 110 further moves and the search button of the input unit 116 is pressed, the wireless communication unit 113 determines the distance from the wireless tag 120 as in step S104 described above. The measured distance information is provided to the control unit 111 and the position estimation unit 115. Then, the position measurement unit 112 acquires information on the relative position between the first measurement position (the position in step S103 described above) and the current position of the object search device 110, and the control unit 111, position estimation Given to part 115. Then, the output unit 117 is controlled by the control unit 111, and an asterisk indicating the positional relationship with the third measurement position and an error bar indicating the height are further displayed on the display (S105).

  Then, in the position estimation unit 115, based on the information about the position given from the position measurement unit 112 and the information about the distance to the wireless tag 120 given from the wireless communication unit 113 in steps S103 to S105 described above, A relative position between the object search device 110 and the search target article 130 (wireless tag 120) is estimated, and information on the estimated position is given to the control unit 111 (S106).

  Then, the output unit 117 is controlled by the control unit 111, and as shown in FIG. 3 described above, the current position of the object search device 110 (here, the third measurement position is the current position) is displayed on the display. Further, a square mark indicating the positional relationship with the estimated position of the search target article 130 (wireless tag 120) and an error bar indicating the height are further displayed (S107).

  As described above, in the object search device 110, the position of the search target article 130 (wireless tag 120) to be searched is estimated, and information on the estimated position is output to the output unit 117.

(A-3) Effects of First Embodiment According to the first embodiment, the following effects can be achieved.

  By using the object search system 100, the user can easily search the search target article 130 anytime and anywhere simply by attaching the wireless tag 120 to the search target article 130.

  In the information processing apparatus described in Patent Document 1, conducting wire detection, object search, person search, etc., it is necessary to create a fixed station (a radio station fixed at one position), so large-scale equipment and construction are required. However, in the object search system 100 of the present invention, the object search device 110 can be carried by the user and can be moved only in a specific area around the fixed station. Therefore, it is possible to search for articles at any time and anywhere.

  In addition, by displaying the entire image of the search target article 130 in the output unit 117, it is possible to search even if the user himself / herself does not know what form the search target article 130 is in. . Thereby, if the ID number is specified in advance, for example, anyone who is not the person himself can cooperate in searching for things.

  Further, when there is an obstacle between the fixed station and the wireless tag 120 to be searched, a shadow zone (an area where radio waves do not reach and cannot be searched) occurs from the fixed station. Since it is only necessary to use the data at the receivable position obtained by the movement of the search device 110, the shadow zone can be removed.

(B) Second Embodiment Hereinafter, a second embodiment of the object search device and the object search system according to the present invention will be described in detail with reference to the drawings.

(B-1) Configuration of Second Embodiment FIG. 5 is a block diagram showing the overall configuration of the object search system 200 of this embodiment.

  The object search system 200 includes an object search device 210 and a wireless tag 220. Since the object search system 200 according to the second embodiment has substantially the same configuration as the object search system 100 according to the first embodiment, a detailed description thereof will be omitted, and the differences from the first embodiment will be described below. explain.

  Since the wireless tag 220 is substantially the same as that of the first embodiment, the description thereof is omitted.

  The object search apparatus 210 includes a control unit 211, a position measurement unit 212, a wireless communication unit 213, an antenna 214, a position estimation unit 215, an input unit 216, an output unit 217, and an article information storage unit 218.

  The main differences from the object search device 110 of the first embodiment are a configuration in which a radio wave is transmitted to a wireless tag by an antenna and a positional relationship with the wireless tag is measured, and a wireless tag position estimation method.

  FIG. 6 is an explanatory diagram for explaining the difference between the wireless tag position estimation methods in the first embodiment and the second embodiment. In the object search device 110 according to the first embodiment, the wireless communication unit 113 (antenna 114) transmits a radio wave from the object search device 110 in all directions and measures the distance from the wireless tag 120 ( In FIG. 6A, the wireless communication unit 213 (antenna 214) of the second embodiment transmits a radio wave as a directional beam in a plurality of different directions and has a response from the wireless tag 220. The wireless tag 220 is estimated to exist, and the distance from the wireless tag 220 is estimated based on the radio wave information when the radio tag 220 transmits and receives radio waves (see FIG. 6B). .

  FIG. 7 is an explanatory diagram showing an example of the configuration of the antenna 214. In the antenna 214, as a transmitting antenna (antenna that transmits directional beam radio waves in a plurality of directions), for example, as shown in FIG. 7, an array antenna (adaptive array) that can transmit directional beam radio waves in one direction is used. The antenna may be provided with a movable mechanism, and a radio wave may be transmitted while rotating around the receiving antenna. In FIG. 7 described above, two array antennas are rotated. However, the number of array antennas to be rotated may be one or three or more, and the number is not limited. . Moreover, the structure which transmits the electromagnetic wave of a directional beam may be an array antenna which can transmit an electromagnetic wave as a directional beam in several directions, for example. Further, in the antenna 214, as a receiving antenna (antenna for receiving a response radio wave from the wireless tag 220), for example, as shown in FIG. 7, an omnidirectional antenna (for example, a monopole) that receives radio waves from all directions. An antenna or the like).

  Note that the directional beam transmitted from the antenna 214 has a beam width of 15 degrees or less (attenuation of radio wave intensity between the vicinity of the central axis of the beam and the vicinity of about 15 degrees away from the central axis is about 3 db). desirable. Further, the antenna 214 may have means for adjusting the beam width of the directional beam. For example, when the antenna 214 is configured by an array antenna and the direction in which the wireless tag 220 exists needs to be further narrowed, the array antenna has a structure in which the antenna antenna is extended (the antenna length is extended). The beam width of the beam can be further limited.

  In the wireless communication unit 213, for example, the wireless communication unit 213 (antenna 214) transmits a radio wave including data (for example, the transmission time of the radio wave) separated according to the direction in which the radio wave is transmitted in a plurality of directions. It may be determined from which direction the response has returned.

  Hereinafter, an example of a method in which the wireless communication unit 213 (antenna 214) measures the direction and distance in which the wireless tag 220 exists will be described.

  First, when a radio wave is transmitted from the wireless communication unit 213 (antenna 214) toward the wireless tag 220, information including the information regarding the time when the radio wave is transmitted is transmitted. Although not shown, the wireless communication unit 213 has means for storing information about which time and in which direction the radio wave is transmitted, and stores the information every time the radio wave is transmitted. Then, the wireless tag 220 that has transmitted a radio wave from the object search device 210 responds to the object search device 210 including the data relating to the above-described time given from the object search device 210. Then, when the radio communication unit 213 receives the radio wave responded from the radio tag 220, the radio communication unit 213 determines in which direction the response is to the radio wave transmitted based on the information regarding the time given from the radio tag 220, It is determined that the wireless tag 220 exists in the direction in which the response has been made.

  Further, when measuring the distance between the object search device 210 and the wireless tag 220, the distance may be measured based on the above-mentioned time information given from the wireless tag 220 and the current time. You may measure based on the intensity | strength of the electric wave of the response from the wireless tag 220. FIG. For example, the longer the response time, the longer the distance between the object search device 210 and the wireless tag 220 may be determined. Further, for example, it may be determined that the stronger the response radio wave from the wireless tag 220 is, the shorter the distance from the wireless tag 220 is.

  As in the above example, the wireless communication unit 213 of the second embodiment measures the direction and distance in which the wireless tag 220 exists.

  The position estimation unit 215 determines a relative position between the position where the object search device 210 exists and the position where the wireless tag 220 exists based on the information given from the position measurement unit 212 and the wireless communication unit 213. To be estimated. Further, when a plurality of pieces of measurement result information are given from the wireless communication unit 213 and the position measurement unit 212, the position estimation unit 215 determines the position where the wireless tag 220 exists based on the given pieces of information. It may be estimated. For example, the center of gravity of each position estimated from a plurality of measurement results may be estimated as the position where the wireless tag 220 exists.

  The input unit 216 is substantially the same as the input unit 116 of the first embodiment, and thus detailed description thereof will be omitted. However, when the antenna 214 has means for adjusting the beam width of the directional beam. May have, for example, a button for adjusting the size as input means for adjusting the size of the beam width.

  The output unit 217 is substantially the same as the output unit 117 of the first embodiment, and thus detailed description thereof is omitted. However, the object search device 210 of the second embodiment is configured to use a wireless tag only at one measurement position. Since the position of 220 can be estimated, the position may be displayed for each past measurement position only when the position of the wireless tag 220 is estimated based on a plurality of measurement results.

(B-2) Operation of Second Embodiment Next, an operation of searching for the search target article 230 (wireless tag 220) in the object search system having the above configuration will be described.

  FIG. 8 is a sequence diagram illustrating an operation in which the object search apparatus 210 estimates the position of the wireless tag 220.

  First, in the control unit 211 of the object search apparatus 210, ID information of the wireless tag 220 attached to the search target article 230 to be searched is acquired. This process is performed in steps S101 and S102 in FIG. Since the processing is the same as that described above, description thereof is omitted (S201, S202).

  Next, when a signal for starting a search is input from the user to the input unit 216 (for example, the search button described above is pressed), the antenna 214 starts rotating in the antenna 214, and the wireless communication unit 213 (the antenna 214) is started. ) And the wireless tag 220. Then, in the wireless communication unit 213 (antenna 214), the direction and distance from the object search device 210 to the wireless tag 220 are measured (S203).

  Next, the position estimation unit 215 estimates the position where the search target article 230 (wireless tag 220) is present, and gives information on the position estimated to be present to the control unit 211 (S204).

  Then, the output unit 217 is controlled by the control unit 211, and information indicating the positional relationship between the current position of the object search device 210 and the estimated position of the search target wireless tag 220 is displayed on the display (S205). .

  FIG. 9 is an explanatory diagram for explaining a method for narrowing down the position of the wireless tag (search target article) in the object search system 200.

  When the approximate position of the wireless tag 220 can be determined in steps S203 to S205 described above, the user who has the object search device 210 moves in that direction, and further performs the processes in steps S203 to S205 described above. Then, the direction and distance in which the search target article 230 (wireless tag 220) exists may be further narrowed down and repeated until the user finds the search target article 230 (see FIG. 9A). Further, when the antenna 214 has means for adjusting the beam width of the directional beam, the beam width is further limited (for example, adjustment is performed by operating the button of the input unit 216). Similarly, the processing in steps S203 to S205 described above may be performed to further narrow down the direction and distance in which the search target article 230 (wireless tag 220) exists (see FIG. 9B).

(B-3) Effects of Second Embodiment According to the second embodiment, the following effects can be achieved.

  The antenna 214 is a transmitting antenna (an array antenna that can transmit directional beam radio waves in one direction), rotates around the reception antenna, and transmits directional beam radio waves in a plurality of directions. A certain direction of the wireless tag 220 attached to 230 can be determined. At this time, when the antenna 214 is an array antenna, it is not necessary to arrange small array elements densely and perform phasing or the like to obtain directions in all directions, and inexpensively (low cost) in all directions. An antenna that transmits radio waves can be constructed. Also, by rotating the transmission antenna around the reception antenna, radio waves can be transmitted and received at a closer position, and the response time can be accurately measured in communication with the wireless tag and the antenna can be downsized. it can.

  In the first embodiment, the position of the wireless tag 120 needs to be communicated with the wireless tag 120 by moving the object search device 110 to three or more measurement positions, but in the second embodiment, The position of the wireless tag 220 can be estimated only by measurement at one place. For example, when it is desired to grasp from a single point what kind of area there is and what kind of people are in a certain wide area, it is possible to specify the general direction while sitting in the seat.

(C) Other Embodiments The present invention is not limited to the above-described embodiment, and may include modified embodiments as exemplified below.

(C-1) In each of the embodiments described above, the position measurement unit includes an acceleration sensor, but the position information accuracy may deteriorate due to thermal noise of an amplifier connected to the acceleration sensor.

In order to avoid this, in the position measurement unit, the acceleration sensor itself may be rotated more than a predetermined value, data may be sampled periodically, and detection may be performed at that cycle. As a result, as shown in FIG. 10, the baseband (fundamental wave) acceleration signal can be analyzed by raising it to a higher band than the band in which noise exists, so that noise components other than the acceleration signal can be removed. In addition, it is preferable that the speed which rotates an acceleration sensor shall be 100 Hz or more.

  Further, for example, the input unit may be provided with a button for rotating the acceleration sensor as described above, and when the user presses the button, the acceleration sensor is rotated to detect the position with high accuracy.

  Further, in the second embodiment, as shown in FIG. 7 described above, the array antenna that can transmit radio waves as a directional beam in one direction is provided with a movable mechanism to transmit radio waves to the wireless tag 220 while performing rotational motion. Although the configuration for transmitting is given as an example, as shown in FIG. 11, the array antenna (transmitting antenna) and the acceleration sensor of the position measuring unit may be rotated as one unit. As a result, the acceleration sensor itself can be rotated more than a predetermined amount in the same manner as described above, and noise components other than the acceleration signal can be removed as described above.

(C-2) The object search device in each of the above embodiments may be applied to a wireless communication terminal such as a mobile phone terminal, a transceiver, or a cordless phone terminal. Thereby, the user can search for what he / she wants to find at any time without carrying other devices. For example, the case where the object search device 110 of the first embodiment is applied to a mobile phone terminal will be described below.

  A user attaches a wireless tag to something that he / she carries with him / her and uses the ID information of the wireless tag in the article information storage unit 118 and a search photographed with a digital camera or the like of the mobile phone terminal. Information obtained by linking the image of the target article 130 is stored. Then, when the user loses the search target article 130, a button for starting a search in the input unit 116 by holding the mobile phone terminal having the object search device 110 (for example, the search button of the input unit 116 described above) Button). Further, the user repeatedly moves the place and presses the button for starting the search twice or more, and displays the position of the wireless tag 120 estimated by the position estimation unit 115 on the display of the mobile phone terminal, thereby allowing the user to The position of the lost search target article 130 is recognized. In addition, when the user wants to know the position of the wireless tag 120 in more detail, when the user presses the button for moving the place and starting the search, he or she goes up and somewhere in the space ( By moving (in three dimensions), a more detailed position of the wireless tag 120 can be estimated.

(C-3) When the object search device in each of the above-described embodiments is applied to a small wireless communication terminal such as a mobile phone terminal, for example, the shorter the antenna length of the mounted antenna, the better for miniaturization. However, the antenna length is related to the frequency of radio waves communicated between the object search device and the wireless tag. Therefore, the antenna length in the object search device and the frequency of the radio wave communicated with the wireless tag may be determined and constructed based on the following calculated values.

  FIG. 13 is a graph showing the relationship between the frequency band of the radio wave used for communication with the wireless tag and the antenna length necessary on the object search device side, using calculated values. Note that the antenna length L (see FIG. 12A) when the antenna 114 of the first embodiment is a monopole antenna is calculated by the following equation (1).

  In the antenna 214 of the second embodiment, when the antenna 214 is the antenna as shown in FIG. 7 and the angle of the directional beam is 15 degrees (see FIG. 12B). ), The sine value of the half width at half maximum (7.5 degrees) (hereinafter referred to as “angle θ”) is calculated by the following equation (2). In FIG. 13 described above, the antenna length L of the array antenna of the second embodiment is calculated based on the following equation (2). In the following formulas (1) and (2), λ represents the wavelength of the radio wave used for communication with the wireless tag.

L = λ / 4 (1)
sin (θ) = 1.4λ / (πL) (2)
As shown in FIG. 13, for example, the antenna 114 in the first embodiment is a monopole antenna, and a necessary antenna length (hereinafter referred to as “antenna length L”) when communication with the wireless tag 120 is performed in a frequency band of about 2 GHz. “)” Is about 4 cm. In the antenna 214 of the second embodiment, in order to suppress the antenna length L of the array antenna to the same level as that of the monopole antenna of the first embodiment (4 cm or less), wireless communication is performed in a frequency band of about 26 GHz. It can be seen that it is necessary to communicate with the tag 220. Therefore, for the antenna 214 of the second embodiment, using an RFID system in a quasi-millimeter wave band (30 GHz band) is desirable for downsizing the object search apparatus. In the graph of FIG. 13, the angle θ in the above equation (2) is calculated as 7.5 degrees, but a value calculated from another angle may be used.

(C-4) In each of the embodiments described above, the object search device itself has the article information storage unit and stores the image data of the search target article. And the like may be read by the object search device.

  Further, the image data of the search target article may be stored in advance in the wireless tag itself, and may be read by the object searching device when the object searching device communicates with the wireless tag in the search process.

(C-5) In each of the above-described embodiments, the example in which the user having the object search apparatus moves, changes the position, and measures the state of communication with the wireless tag has been described. The button for starting the search in the input unit (for example, the one corresponding to the search button of the input unit described above) is pressed once to communicate with the wireless tag at a predetermined time interval to measure the distance. Anyway. Alternatively, the measured distances may be merged sequentially, and the position of the wireless tag may be estimated based on many samples. Thereby, the estimated position of the wireless tag can be improved.

(C-6) In the object search system 200 of the second embodiment, the transmitting antenna (array antenna capable of transmitting a directional beam radio wave in one direction) is directed in a plurality of directions while rotating around the receiving antenna. Based on the response status of the wireless tag 120, the direction in which the wireless tag 120 is located can be estimated. Therefore, when the object search system 200 determines the direction in which the wireless tag is roughly located in a wide range, for example, for searching for people in a crowded situation or for checking inventory in a warehouse. It is suitable for use when used.

(C-7) In each of the above-described embodiments, all the wireless tags transmitted from the object search device respond to the object search device. However, when transmitting the radio waves from the object search device to the wireless tag, In addition, only the wireless tag having the ID information may respond, including the ID information of the wireless tag being searched. In that case, the wireless tag side needs to have means (program or the like) that responds only to specific information. As a result, even if the wireless tag is flooded in the world, it is possible to construct a system that makes a response only from the necessary wireless tag and searches for only the necessary one.

(C-8) In the second embodiment, the object search device 210 includes a position measurement unit 212, measures the position of the object search device 210, and outputs the output to the output unit 217 when the output is performed. The positional relationship between the object search device 210 and the search target article 230 (wireless tag 220) is displayed, but the position measurement unit 212 may not be provided. In that case, in the output unit 217, the object search device 210 may display the display as being present at the same position as when the direction and distance of the wireless tag 220 are measured. In the second embodiment, the object search device 210 may measure and output only the direction.

(C-9) In the second embodiment, the wireless communication unit 213 (antenna 214) of the object search apparatus 210 transmits radio waves as directional beams in a plurality of different directions, and there is a response from the wireless tag 220. However, the transmitting antenna may transmit radio waves in all directions, and the receiving antenna may receive radio waves only from a specific direction. For example, in FIG. 7 described above, the directivities of the transmitting and receiving antennas are switched, the transmitting antenna transmits radio waves in all directions, and the receiving antenna is an array antenna that can receive radio waves from only one direction. It is good also as a structure which receives an electromagnetic wave, rotating (adaptive array antenna). In this case, when the wireless communication unit 213 (antenna 214) receives a response radio wave from the wireless tag 220, the wireless communication unit 213 (antenna 214) determines that the wireless tag 220 exists in the direction in which the receiving array antenna faces.

(C-10) In the first embodiment, the object search apparatus 110 measures the distance to the wireless tag 120 from three different measurement positions and estimates the position of the wireless tag 120 as shown in FIG. However, the distance from the two measurement positions to the wireless tag 120 may be measured to estimate the position of the wireless tag 120. For example, as shown in FIG. 2 described above, the intersection of a circle whose radius is the distance from the measurement position 1 to the wireless tag 120 and a circle whose radius is the distance from the measurement position 2 to the wireless tag 120 is narrowed to two points. Therefore, the position measuring unit 112 may estimate that the search target article 130 (wireless tag 120) exists at one of the two points. At that time, the output unit 117 may output both of the two estimated positions as the estimated position of the search target article 130.

1 is a block diagram illustrating an overall configuration of an object search system according to a first embodiment. It is explanatory drawing explaining the method to estimate the position of a wireless tag in the object search system of 1st Embodiment. It is explanatory drawing explaining the example of the input / output in the object search apparatus of 1st Embodiment. FIG. 5 is a sequence diagram illustrating a search operation in the object search device according to the first embodiment. It is a block diagram which shows the whole structure of the object search system of 2nd Embodiment. It is explanatory drawing explaining the difference of the method of estimating the position of the radio | wireless tag (search target article | item) with the object search system of 1st Embodiment and 2nd Embodiment. It is explanatory drawing explaining the example of the structure of the antenna in the object search system of 2nd Embodiment. It is the sequence diagram which showed the operation | movement of the search in the object search apparatus of 2nd Embodiment. In the object search system of 2nd Embodiment, it is explanatory drawing explaining the method of narrowing down the position of a wireless tag (search object article). It is explanatory drawing explaining the noise removal in the position measurement part of embodiment. It is explanatory drawing shown about the example at the time of comprising the acceleration sensor and transmission antenna of 2nd Embodiment as one unit. It is explanatory drawing explaining the antenna length of the monopole antenna of 1st Embodiment, and the array antenna of 2nd Embodiment. It is explanatory drawing shown about the relationship between the antenna length in an object search apparatus, and the frequency used for communication with a wireless tag.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 100 ... Object search system, 110 ... Object search apparatus, 111 ... Control part, 112 ... Position measurement part, 113 ... Wireless communication part, 114 ... Antenna, 115 ... Position estimation part, 116 ... Input part, 117 ... Output part, 118 ... article information storage unit, 120 ... wireless tag, 130 ... search object.

Claims (6)

In an object search device for searching for a search target object,
Wireless communication means for communicating with a wireless tag attached to the search target object;
A distance measuring unit that measures a distance between the object search device and the wireless tag based on radio wave information when the wireless communication unit transmits and receives radio waves to and from the wireless tag;
The distance measuring means measures the distance, and obtains position information of a measurement position, and measurement position information acquisition means;
When the distance is measured at the two or more different measurement positions by the distance measurement means, position estimation means for estimating the position of the search target object based on the distance and position information of the measurement position When,
An object search apparatus comprising: output means for outputting information on the position of the search target object estimated by the positional relationship estimation means. An antenna that can be directed in several different directions;
Wireless communication means for communicating with the wireless tag attached to the search target object via the antenna;
Direction measuring means for measuring the direction in which the antenna transmits or receives radio waves when the wireless communication means communicates with the wireless tag; and
Positional relationship estimation means for estimating that the search target object exists in the direction measured by the direction measurement means;
An object search apparatus comprising: output means for outputting information on the direction of the search target object estimated by the positional relationship estimation means. The wireless communication means further has a distance measuring means for measuring a distance between the object search device and the wireless tag based on radio wave information when transmitting and receiving radio waves with the wireless tag,
The positional relationship estimation means estimates that the search target object exists in the direction measured by the direction measurement means and the position of the distance measured by the distance measurement means,
The object search apparatus according to claim 2, wherein the output means outputs information on the position of the search target object estimated by the positional relationship estimation means.   The antenna includes a first antenna unit and a second antenna unit, and the first antenna unit is an omnidirectional antenna used for either transmission or reception, and the second antenna unit The antenna unit is an antenna that is used for the other of transmission or reception, and can direct its direction only in one direction, and is around the first antenna unit with the first antenna unit as a center of rotation. The object search device according to claim 2, wherein the object search device emits or receives a radio wave while rotating.   A wireless communication terminal, comprising the object search device according to claim 1.   An object search system comprising: the object search device according to claim 1; and a wireless tag attached to a search target object.

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