JP2016090285A - Positioning system and positioning method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce power consumption of an information terminal, while properly and intermittently positioning the information terminal.SOLUTION: An information terminal 10 includes: sensors 11, 12, and 13 for acquiring sensor information for use in an estimation of a position of the self terminal 10; a graph database 14 that stores conversion information for specifying nodes as positions abstracted from sensor information acquired by the sensors 11, 12, and 13, and link information representing links among the nodes; a sensor information acquisition section 15 for acquiring the sensor information acquired by the sensors 11, 12, and 13; a node specification section 16 for specifying a node in which the self terminal 10 is located from the acquired sensor information on the basis of the conversion information; and a control section 17 for controlling acquisition of the sensor information by the sensors 11, 12, and 13 on the basis of the link information and the specified node.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a position positioning system and a position positioning method for estimating the position of an information terminal.

  2. Description of the Related Art Conventionally, a location information service that delivers information suitable for a user's location using a location measured by an information terminal has attracted attention (for example, see Patent Document 1).

JP 2014-191373 A

  Examples of location information services include navigation and O2O (Online to Offline) marketing. In particular, the market for O2O marketing utilizing location information services is expected to expand significantly in the future.

  As a method for acquiring the position of the user, positioning by a GPS (Global Positioning System) signal is representative. In position measurement using a GPS signal, high-precision positioning is possible outdoors. However, it is difficult to receive GPS signals indoors, and indoor positioning accuracy is not practical. As a method for positioning indoors, a positioning method using a radio wave intensity and a radio wave arrival time transmitted from a short-range wireless communication device installed indoors is known.

  For example, in order to perform O2O marketing, it is necessary to always grasp the position of the user. For this reason, it is necessary to set the interval of position measurement performed using the GPS signal or the radio wave for short-range wireless communication to be short and perform the position measurement frequently. However, high-frequency positioning has a problem that the power consumption of the information terminal increases and the usability of the information terminal is reduced.

  The present invention has been made in view of the above problems, and provides a positioning system and a positioning method that can reduce power consumption of an information terminal while appropriately performing continuous positioning of the information terminal. The purpose is to provide.

  In order to achieve the above object, a position positioning system according to the present invention is a position positioning system that estimates the position of an information terminal including a sensor that acquires sensor information used to estimate the position of the terminal. A database that stores conversion information for identifying nodes that are abstracted from the sensor information acquired by, and link information indicating links between the nodes, and sensor information acquired by the sensor of the information terminal Sensor information acquisition means for acquiring the information, node specification means for specifying the node where the information terminal is located, from the sensor information acquired by the sensor information acquisition means based on the conversion information stored in the graph database, and the graph database The stored link information and the node specified by the node specifying means And Zui, and control means for controlling the acquisition of the sensor information by the information terminal.

  In the position positioning system according to the present invention, a node that is a position abstracted as the position of the information terminal is specified. The node is identified based on sensor information acquired by the sensor of the information terminal. For example, the sensor information is acquired by receiving a GPS signal, a short-range wireless communication radio wave, or the like in the information terminal. In the positioning system according to the present invention, the acquisition of sensor information by the information terminal is controlled based on the node specified as the node where the information terminal is located. Therefore, sensor information can be acquired so as to suppress wasteful power consumption according to the node where the information terminal is located. That is, according to the positioning system according to the present invention, it is possible to reduce power consumption of the information terminal while appropriately performing continuous positioning of the information terminal.

  The graph database further stores information indicating the positional relationship between the nodes as link information, and the control means is linked to the node specified by the node specifying means indicated by the link information stored by the graph database. The time interval for acquiring sensor information by the information terminal may be determined based on the positional relationship with the other node. According to this configuration, it is possible to reduce power consumption of the information terminal while appropriately performing continuous positioning of the information terminal by making the time interval for acquiring sensor information by the information terminal appropriate. .

  The control means may determine a time interval for acquiring sensor information by the information terminal based on a preset moving speed of the user of the information terminal. According to this configuration, the time interval can be made more appropriate.

  The graph database further stores, as link information, information indicating the staying time of the user at each node, and the control means is the user staying at the node specified by the node specifying means indicated by the link information stored by the graph database. The time interval for obtaining sensor information by the information terminal may be determined based on the time. According to this configuration, the time interval can be made more appropriate.

  The graph database stores information indicating the user's stay time at each node according to the user's attribute, and the control means is based on the information terminal based on the user's stay time according to the user's attribute of the information terminal. It is good also as determining the time interval of acquisition of sensor information. According to this structure, the said time interval can be made more suitable according to a user's attribute.

  The information terminal includes a plurality of types of sensors, and the control means is based on the characteristics of another node linked to the node identified by the node identification means indicated by the link information stored by the graph database. It is good also as determining the kind of sensor which acquires sensor information. According to this configuration, it is possible to reduce power consumption of the information terminal while appropriately performing continuous positioning of the information terminal by appropriately selecting the type of sensor from which the sensor information is acquired.

  The sensor acquires information indicating reception strength of radio waves for short-range wireless communication as sensor information, the sensor information acquisition unit acquires information indicating reception strength at a plurality of timings, and the node specifying unit includes a plurality of node specification units The node where the information terminal is located may be identified from the average and difference of the received strengths. According to this configuration, it is possible to appropriately identify the node where the information terminal is located based on the reception strength of the short-range wireless communication radio wave.

  The position positioning system acquires a plurality of sensor information and information indicating the latitude and longitude of the position where the sensor information is acquired, and generates information stored in the graph database based on the acquired information It is good also as providing a production | generation means. According to this configuration, information stored in the graph database can be automatically generated.

  By the way, the present invention can be described as an invention of a position positioning system as described below as well as an invention of a position positioning system as described above. This is substantially the same invention only in different categories, and has the same operations and effects.

  That is, the position positioning method according to the present invention estimates the position of an information terminal including a sensor that acquires sensor information used for estimating the position of the terminal itself, and is a position abstracted from the sensor information acquired by the sensor. A position positioning method, which is an operation method of a position positioning system comprising a graph database for storing conversion information for identifying a certain node and link information indicating a link between the nodes, and obtained by a sensor of an information terminal A sensor information acquisition step for acquiring sensor information, a node specification step for specifying a node where the information terminal is located from the sensor information acquired in the sensor information acquisition step based on the conversion information stored in the graph database, and a graph Link information stored by the database and node specific steps Based on the specified node in, and a control step of controlling the acquisition of the sensor information by the information terminal.

  According to the present invention, sensor information can be acquired so as to suppress wasteful power consumption according to a node where an information terminal is located. That is, according to the present invention, it is possible to reduce power consumption of the information terminal while appropriately performing continuous positioning of the information terminal.

It is a figure which shows the function structure of the information terminal which is a position positioning system which concerns on embodiment of this invention. It is a figure which shows notionally the node in embodiment. It is a figure which shows the example of the sensor information acquired by the sensor with which an information terminal is equipped. It is a figure which shows the example of the information memorize | stored in a graph database. It is a figure which shows the hardware constitutions of the information terminal which is a position positioning system which concerns on embodiment of this invention. It is a flowchart which shows the whole position positioning method which is a process performed with the information terminal which is a position positioning system which concerns on embodiment of this invention. It is a flowchart which shows the specific process (abstraction process) of a node in a position positioning method. It is a flowchart which shows the threshold value process in the node specific process (abstraction process). It is a flowchart which shows the calculation process of a sensor acquisition timing in the position positioning method.

  Hereinafter, embodiments of a positioning system and a positioning method according to the present invention will be described in detail with reference to the drawings. In the description of the drawings, the same elements are denoted by the same reference numerals, and redundant description is omitted.

  FIG. 1 shows an information terminal 10 which is a position positioning system according to this embodiment. The information terminal 10 is a device that estimates the position of the terminal 10 (measures the position of the terminal 10). The information terminal 10 is used by being carried (carried) by a user. Specifically, the information terminal 10 corresponds to a mobile phone including a smartphone. The position of the terminal 10 estimated by the information terminal 10 is used, for example, in the above-described position information service in which information corresponding to the position is provided. For this reason, the positioning of the terminal 10 is continuously repeated.

  Information indicating the position of the information terminal 10 obtained by position measurement of the information terminal 10 is information indicating a node that is an abstracted position. Here, the node will be described. A node is an abstraction of a position within a building having a certain range or an outdoor position. For example, as shown in FIG. 2, each store in the building and (in front of the store) correspond to one node 20. A road in front of the building corresponds to one node 20. A link (connection relationship, connection) 21 is set between the nodes 20. The link 21 is set based on, for example, whether or not the user can move. For example, the entrance of a building facing the aisle is connected to the store front (when entering the building from the aisle, first enter the store front, or exit from the store in front of the store), A link 21 is set between the node 20 in the passage and the node 20 in front of the store. Moreover, since the entrance / exit of each store in a building is connected with the store front, the link 21 is set between the node 20 of each store and the node 20 in front of the store.

  The node 20 and the link 21 can be associated with information indicating their characteristics. For example, the link 21 is associated with a distance. Information indicating the characteristics will be described later in more detail. The estimation of the position of the terminal 10 by the information terminal 10 is performed using the information of the node 20 and the link 21.

  Subsequently, functions of the information terminal 10 according to the present invention will be described. As shown in FIG. 1, the information terminal 10 includes a GPS signal receiving unit 11, a WiFi signal receiving unit 12, a BLE signal receiving unit 13, a graph database 14, a sensor information acquisition unit 15, a node identification unit 16, And a control unit 17. Note that the information terminal 10 may have a function normally provided in a mobile phone or the like, including a function for receiving provision of a location information service.

  The GPS signal receiving unit 11, the WiFi signal receiving unit 12, and the BLE signal receiving unit 13 are sensors that acquire (detect, sense) sensor information used for estimating a node that is the position of the terminal 10. The GPS signal receiving unit 11 receives GPS signals from GPS satellites. Further, the GPS signal receiving unit 11 performs a positioning calculation based on the received GPS signal, and calculates the latitude and longitude of the terminal 10 as sensor information. The GPS signal reception unit 11 outputs information indicating the calculated latitude and longitude of the terminal 10 to the sensor information acquisition unit 15. FIG. 3A shows an example (GPS table) of information indicating latitude (latitude) and longitude (longitude), which is sensor information calculated (acquired) by the GPS signal receiving unit 11.

  The WiFi signal receiving unit 12 is a unit that receives a signal for WiFi (registered trademark) from a short-range wireless communication device (WiFi access point). The BLE signal receiving unit 13 is means for receiving a signal for BLE (Bluetooth Low Energy) from a short-range wireless communication device (Bluetooth (registered trademark) device, BLE device). WiFi and BLE are methods for performing short-range wireless communication. That is, the WiFi signal receiving unit 12 and the BLE signal receiving unit 13 receive radio waves for near field communication. The WiFi signal receiving unit 12 and the BLE signal receiving unit 13 uniquely identify the short-range wireless communication device that is the transmission source of the radio wave associated with each other as sensor information based on the received radio wave, and the radio wave The information which shows the receiving strength of is acquired.

  The short-range wireless communication device that is the transmission source of the radio wave is fixed in advance in a range where the information terminal 10 can be positioned. For example, the short-range wireless communication device is provided in association with the node. However, short-range wireless communication devices need not be provided for all nodes. Specifically, the short-range wireless communication device may be provided only for an indoor node where GPS positioning is difficult, and the short-range wireless communication device may not be provided for an outdoor node. The short-range wireless communication device transmits radio waves that can be received by the WiFi signal receiving unit 12 or the BLE signal receiving unit 13. As information for uniquely specifying the near field communication device, a BSSID (Basic Service Set Identifier) preset in the near field communication device can be used. BSSID is also generally called a MAC address. As information indicating the reception strength of the radio wave, RSSI (Received Signal Strength Indication, Received Signal Strength Indicator) can be used.

  When a plurality of short-range wireless communication devices are installed near the information terminal 10, radio waves from a plurality of short-range wireless communication devices may be received at the same time. For this reason, one sensor information can include information indicating reception strengths related to radio waves from a plurality of short-range wireless communication devices. As for the radio wave reception intensity, radio wave reception intensity (for example, reception intensity for five times) received at a plurality of different timings may be used as one sensor information. The WiFi signal receiving unit 12 and the BLE signal receiving unit 13 use the WiFi / BLE signal information list as a WiFi / BLE signal information list for identifying the acquired short-range wireless communication device that is the transmission source of the radio wave and information indicating the reception intensity of the radio wave. Output to the sensor information acquisition unit 15. FIG. 3B shows an example of BSSID and RSSI (WiFi / BLE signal information list) associated with each other, which are sensor information acquired by the WiFi signal receiving unit 12 and the BLE signal receiving unit 13.

  As described above, the information terminal 10 includes the sensors 11, 12, and 13 that acquire a plurality of types of sensor information. Further, the GPS signal receiving unit 11 is performed under the control of the control unit 17 as will be described later. In addition, when the GPS signal receiving unit 11, the WiFi signal receiving unit 12, and the BLE signal receiving unit 13 acquire sensor information under the control of the control unit 17 (receive signal etc.), the information terminal 10 Power consumption associated with the acquisition is made.

  The graph database 14 is conversion information for specifying (abstraction) a node indicating the position of the information terminal 10 from the sensor information acquired by the sensors 11, 12, and 13, and link information indicating a link between the nodes. It is a database that stores the link table 14b. The graph database 14 stores conversion information in the node table 14a. The graph database 14 stores link information in the link table 14b.

  The node table 14a is, for example, a table that stores information shown in FIG. As shown in FIG. 4A, the node table 14a associates node ID, center latitude / longitude, radius (m), average stay time (second), BSSID, th1, th2, and th3 information for each node. Store. The node ID is an ID number that is information for uniquely identifying a node. The center latitude / longitude is information indicating the latitude and longitude of the position of the center of the node. The radius (m) is information indicating the radius from the center of the node indicating the range of the node. The average stay time (seconds) is information indicating an average time during which the user stays at the node (for example, an average time during which the user stayed at the node in the past). BSSID is the BSSID of the short-range wireless communication device associated with the node. th1, th2, and th3 are values used when specifying a node. These will be described later in more detail.

  Among the above information, information on the node ID, the central latitude / longitude, and the radius (m) (information from the first column to the third column of the node table 14a) is essential information in all the nodes. Among the above information, the BSSID, th1, th2, and th3 information (the information from the fifth column to the eighth column of the node table 14a) is installed with the short-range wireless communication device associated with the node. Stored if it has been.

  The link table 14b is a table that stores information shown in FIG. 4B, for example. As shown in FIG. 4 (b), the link table 14b shows information on the node ID, the adjacent node ID, the distance (m) between the centers, and the height difference (m) for each of two nodes adjacent to each other. Store them in association with each other. The node ID is an ID number that is information for uniquely identifying the one node. The adjacent node ID is an ID number that is information for uniquely specifying a node adjacent to the one node. The distance (m) between the centers is information indicating the distance between the center latitude and longitude of two adjacent nodes (two nodes indicated by the node ID in the first column and the adjacent node ID in the second column). The height difference (m) is information indicating the height difference between the central latitudes and longitudes of the two adjacent nodes. As described above, in the link table 14b, information indicating the positional relationship between linked nodes is stored as link information in addition to which nodes are linked.

  Information stored in the node table 14a and the link table 14b is input in advance by, for example, a user or a communication provider that provides a mobile communication function to the information terminal 10.

  The sensor information acquisition unit 15 is a sensor information acquisition unit that acquires sensor information acquired by the sensors 11, 12, and 13 of the information terminal 10. The sensor information acquisition unit 15 acquires sensor information by inputting sensor information from the sensors 11, 12, and 13. Specifically, the sensor information acquisition unit 15 acquires information indicating latitude and longitude (for example, information shown in FIG. 3A) as sensor information from the GPS signal reception unit 11, as described above. The sensor information acquisition unit 15 receives a WiFi / BLE signal information list including BSSID and RSSI associated with each other as described above from the WiFi signal reception unit 12 and the BLE signal reception unit 13 (for example, in FIG. 3B). Information). That is, when the sensor information is information indicating the reception intensity of radio waves for short-range wireless communication, the sensor information acquisition unit 15 may acquire information indicating the reception intensity at a plurality of timings. The sensor information acquisition unit 15 outputs the acquired sensor information to the node identification unit 16.

  The node identification unit 16 is a node identification unit that identifies the node where the terminal 10 is located from the sensor information input from the sensor information acquisition unit 15. The node specifying unit 16 specifies the node based on the conversion information stored by the node table 14a of the graph database 14. That is, the node specifying unit 16 abstracts the position of the terminal 10 itself. Specifically, the node specifying unit 16 specifies a node as follows. First, a case where a node is specified from a WiFi / BLE signal information list including BSSID and RSSI that are sensor information acquired by the WiFi signal receiving unit 12 and the BLE signal receiving unit 13 will be described.

  The node specifying unit 16 refers to the node table 14a, and among BSSIDs (acquired BSSIDs) included in the WiFi / BLE signal information list, BSSIDs (node table) not included in the BSSID column information of the node table 14a It is determined whether there is an unknown BSSID not described in 14a. When determining that there is such a BSSID, the node specifying unit 16 deletes information related to the BSSID from the list. After performing this process, when no element (one BSSID corresponds to one element) remains in the list, the node specifying unit 16 determines that the node cannot be specified from the list, The node specifying process (abstraction process) based on the list is terminated.

  If the elements remain in the WiFi / BLE signal information list after performing the above processing, the node specifying unit 16 calculates the average for each BSSID of the RSSI associated with each BSSID included in the list. To do. The node specifying unit 16 refers to the information on th1 stored in the node table 14a in association with the BSSID. For each BSSID, the node specifying unit 16 compares the calculated RSSI average with the referred th1 to determine whether the average exceeds th1 (whether the average exceeds th1). In addition, it is good also as not only whether it is over whether it is above, but whether it is above (it is the same also about the following criteria). The node specifying unit 16 deletes information related to the BSSID that is determined that the average does not exceed th1 from the list. If no element remains in the list after this processing is performed, the node specification unit 16 determines that the node cannot be specified from the list, and performs node specification processing (abstraction) based on the list. Process).

  If there is an element remaining in the list and only one element is included in the list, the node identifying unit 16 refers to the node table 14a and determines the node ID corresponding to the BSSID as its own terminal 10. And the node ID of the node where the user is located (the node where the user is staying).

  If there are two or more elements included in the list, the node specifying unit 16 extracts the BSSIDs with the highest average of the calculated RSSIs from those elements. The node specifying unit 16 calculates a difference between the maximum values of the individual RSSIs associated with the extracted two BSSIDs. This difference is called DiffMax. The node specifying unit 16 refers to the information of th2 stored in the node table 14a in association with the BSSID associated with the largest RSSI (maximum value) of the two BSSIDs related to the difference. The node specifying unit 16 compares the calculated difference with the referenced th2 and determines whether or not the difference exceeds th2 (whether or not the difference exceeds th2).

  When the node identifying unit 16 determines that the difference exceeds th2, the node identifying unit 16 refers to the node table 14a and the own terminal 10 locates the node ID corresponding to the BSSID associated with the largest RSSI (maximum value). And the node ID of the node (the node where the user is staying). If the node specifying unit 16 determines that the difference does not exceed th2, then the node specifying unit 16 calculates a difference between the averages of RSSIs associated with the two BSSIDs extracted as described above. This difference is called DiffAve. The node specifying unit 16 refers to the information of th3 stored in the node table 14a in association with the BSSID associated with the largest average RSSI value among the two BSSIDs related to the difference. The node specifying unit 16 compares the calculated difference with the referenced th3, and determines whether or not the difference exceeds th3 (whether or not the difference exceeds th3).

  When the node specifying unit 16 determines that the difference exceeds th3, the own terminal 10 locates the node ID corresponding to the BSSID associated with the largest RSSI average value with reference to the node table 14a. The node ID of the node (the node where the user is staying) is specified. When the node identification unit 16 determines that the difference does not exceed th3, the node identification unit 16 determines that the node cannot be identified from the list, and performs node identification processing (abstraction processing) based on the list. ) Ends. As described above, the node specifying unit 16 specifies the node where the terminal 10 is located from the average and difference of the plurality of reception strengths. The node specifying unit 16 outputs a node ID, which is information indicating the node of the own terminal 10 specified based on the sensor information obtained from the short-range wireless communication radio wave, to the control unit 17. If the node cannot be identified from the WiFi / BLE signal information list, the node identification unit 16 may output information indicating that fact (for example, NULL) to the control unit 17.

  Next, a case where a node is specified from information indicating latitude and longitude, which is sensor information acquired by the GPS signal receiving unit 11, will be described. The node specifying unit 16 refers to the node table 14a and acquires information on the central latitude and longitude and the radius (m) of each node. The node specifying unit 16 calculates the range of each node from the acquired information about the central latitude and longitude and the radius (m) of each node. The node specifying unit 16 determines whether the latitude and longitude indicated by the information input from the GPS signal receiving unit 11 are included in the calculated range of each node. The node specifying unit 16 specifies a node including the latitude and longitude indicated by the information acquired by the GPS signal receiving unit 11 as a node (node where the user is staying) where the terminal 10 is located.

  The node specifying unit 16 outputs a node ID, which is information indicating the node of the own terminal 10 specified based on the sensor information obtained by GPS, to the control unit 17. Note that the specification of a node based on sensor information obtained by GPS may be performed when the node cannot be specified from sensor information obtained from radio waves for short-range wireless communication.

  The node information specified by the node specifying unit 16 is used for the above-described location information service. The node specifying unit 16 outputs (transmits) the node to other modules and other devices so that the user can receive the location information service.

  The control unit 17 controls acquisition of sensor information by the sensors 11, 12, and 13 in the own terminal 10 based on the link information stored in the link table 14 b of the graph database 14 and the node specified by the node specifying unit 16. Control means for changing (changing the sensor operation mode). Specifically, the control unit 17 performs control as follows.

  The control unit 17 is based on the positional relationship between the node specified by the node specifying unit 16 (the node where the terminal 10 is located) and another node linked (connected) indicated by the link information. Thus, the sensor information acquisition time interval (sensor acquisition timing (cycle)) by the sensors 11, 12, 13 is determined. Further, the determination of the time interval may be performed based on a preset moving speed of the user of the terminal 10 itself. Further, the determination of the time interval may be performed based on the stay time of the user in the node (the node where the own terminal 10 is located) specified by the node specifying unit 16 indicated by the link information.

上式において、ｌｅｎｇｔｈは、隣接ノードとの中心間の距離、Δａｌｔｉｔｕｄｅは、隣接ノードとの高低差である。これらの情報は、リンクテーブル１４ｂを参照することで得られる。ａｖｅｒａｇｅ＿ｗａｉｋｉｎｇ＿ｓｐｅｅｄは、人の平均徒歩速度（ユーザの移動速度）である。例えば、ａｖｅｒａｇｅ＿ｗａｉｋｉｎｇ＿ｓｐｅｅｄは、１．１（ｍ／ｓ）とされる。ｗは、高低差を考慮するための重みである。例えば、ｗは、１．５とされる。これらの情報は、例えば、ユーザ又は情報端末１０に対して移動体通信機能を提供する通信事業者によって予め情報端末１０に入力されており、制御部１７に記憶されている。 More specifically, the control unit 17 calculates the time interval (sensor acquisition timing) for acquiring sensor information, that is, the time until acquisition of the next sensor information as follows. The control unit 17 refers to the link table 14b and identifies a node (adjacent node) adjacent to the node identified by the node identifying unit 16 (the staying node). The control unit 17 calculates the movement cost cost for each adjacent node using the following equation.

In the above equation, length is the distance between the centers of adjacent nodes, and Δaltitude is the height difference from the adjacent nodes. Such information can be obtained by referring to the link table 14b. average_waking_speed is the average walking speed of the person (the moving speed of the user). For example, average_waiting_speed is 1.1 (m / s). w is a weight for considering the height difference. For example, w is set to 1.5. Such information is input to the information terminal 10 in advance by a communication provider that provides a mobile communication function to the user or the information terminal 10 and stored in the control unit 17.

上式において、ａｖｅｒａｇｅ＿ｓｔａｙ＿ｔｉｍｅは滞在中ノードの平均滞在時間である。この情報は、リンクテーブル１４ｂを参照することで得られる。ｐ，ｑは、それぞれｍｉｎ＿ｃｏｓｔ及びａｖｅｒａｇｅ＿ｓｔａｙ＿ｔｉｍｅのセンサ取得タイミングに対する重みである。例えば、ｐ，ｑは、それぞれ０．５，０．５とされる。これらの情報は、例えば、ユーザ又は情報端末１０に対して移動体通信機能を提供する通信事業者によって予め情報端末１０に入力されており、制御部１７に記憶されている。 The control unit 17 determines the minimum movement cost min_cost among all the adjacent nodes, and calculates the sensor acquisition timing t (seconds) by the following equation.

In the above equation, average_stay_time is the average stay time of the staying node. This information is obtained by referring to the link table 14b. p and q are weights for sensor acquisition timing of min_cost and average_stay_time, respectively. For example, p and q are 0.5 and 0.5, respectively. Such information is input to the information terminal 10 in advance by a communication provider that provides a mobile communication function to the user or the information terminal 10 and stored in the control unit 17.

  The control unit 17 controls the acquisition of sensor information by the sensors 11, 12, and 13 based on the calculated sensor acquisition timing t (seconds). Specifically, when the time indicated by the calculated sensor acquisition timing t (seconds) has elapsed from the previous sensor information acquisition instruction to the sensors 11, 12, and 13, the control unit 17 detects the sensors 11, 12, and 13. Is instructed to acquire sensor information.

  The control part 17 is good also as instruct | indicating acquisition of sensor information with respect to all the sensors 11, 12, and 13 simultaneously. Alternatively, the control unit 17 may first instruct the WiFi signal receiving unit 12 and the BLE signal receiving unit 13 to acquire sensor information. When the node of the own terminal 10 cannot be specified by the sensor information acquired by the WiFi signal receiving unit 12 and the BLE signal receiving unit 13 (information indicating that from the node specifying unit 16 (for example, NULL) is sent to the control unit 17. When output, the control unit 17 may instruct the GPS signal receiving unit 11 to acquire sensor information.

  Further, the control unit 17 is based on the characteristics of another node that is linked (connected) to the node specified by the node specifying unit 16 (the node where the terminal 10 is located) indicated by the link information. It is good also as deciding the kind of sensor 11,12,13 which acquires sensor information. The characteristic of the node is, for example, whether the node is an indoor node (indoor node) or an outdoor node (outdoor node).

  As described above, the control unit 17 can specify a node (adjacent node) adjacent to the node (the staying node) specified by the node specifying unit 16 by referring to the link table 14b. As described above, the short-range wireless communication device may be provided for the indoor node, and the short-range wireless communication device may not be provided for the outdoor node. Therefore, the node whose information is stored in the BSSID column of the node table 14a is an indoor node, and the node whose information is not stored in the BSSID column (in the example of FIG. 4A, the BSSID column is “-”). Can be determined to be indoor nodes. The control unit 17 refers to the node table 14a for the identified adjacent node, and checks whether information is stored in the BSSID column, thereby determining whether the adjacent node is an outdoor node or an indoor node. Determine if there is.

  If the adjacent node includes an indoor node (if the transition from the node where the user is currently staying to the indoor node is possible), the control unit 17 causes the WiFi signal receiving unit 12 and the BLE signal receiving unit 13 to It instructs the acquisition of sensor information. On the other hand, if the adjacent node does not include the indoor node (if the only node that can transition from the node where the user is currently staying is the outdoor node), the control unit 17 uses the WiFi signal receiving unit 12 and the BLE signal. The reception unit 13 is not instructed to acquire sensor information, and the GPS signal reception unit 11 is instructed to acquire sensor information. The above is the function of the information terminal 10 according to the present invention.

  Subsequently, FIG. 5 shows a hardware configuration of the information terminal 10 according to the present embodiment. As shown in FIG. 5, the information terminal 10 includes a CPU (Central Processing Unit) 101, a RAM (Random Access Memory) 102, a ROM (Read Only Memory) 103, an operation unit 104, a display 105, a GPS receiving module 106, and a GPS receiving unit. The hardware includes an antenna 107, a short-range wireless communication module 108, and a short-range wireless communication antenna 109. Note that the short-range wireless communication module 108 and the short-range wireless communication antenna 109 may each be provided for WiFi and BLE. The functions described above are exhibited by the operation of these components. The above is the configuration of the information terminal 10.

  Subsequently, a position positioning method which is a process (an operation method of the information terminal 10) executed by the information terminal 10 which is the position positioning system according to the present embodiment will be described using the flowcharts of FIGS. This process is performed, for example, when the position of the information terminal 10 is continuously and repeatedly performed by a user operation on the information terminal 10. Specifically, this is the case where the information terminal 10 is in a state of using a location information service that requires a continuous location.

  First, the entire process will be described with reference to the flowchart of FIG. In this process, first, sensor information is acquired by the GPS signal receiving unit 11, the WiFi signal receiving unit 12, and the BLE signal receiving unit 13. The sensor information acquired by the GPS signal receiving unit 11 is information indicating the latitude and longitude of the terminal 10 as shown in FIG. The sensor information acquired by the WiFi signal receiving unit 12 and the BLE signal receiving unit 13 is a WiFi / BLE signal information list as shown in FIG.

  The acquired sensor information is output to the sensor information acquisition unit 15 (S1, sensor information acquisition step). In addition, acquisition of sensor information is performed by control of the control part 17, and electric power is consumed only at the time of the said acquisition. Note that the first acquisition of sensor information by the sensors 11, 12, 13 may be performed, for example, as a trigger when the position positioning of the information terminal 10 is continuously repeated. Specifically, the first acquisition of the first sensor information may be performed by the WiFi signal receiving unit 12 and the BLE signal receiving unit 13 as described above. The sensor information is acquired by the GPS signal receiving unit 11 when the node where the terminal 10 is located cannot be specified by the WiFi signal receiving unit 12 and the BLE signal receiving unit 13 (once the WiFi signal receiving unit 12 and the BLE signal are temporarily received). It may be performed after the node specific processing (S2) is performed from the sensor information acquired by the receiving unit 13.

  The input sensor information is acquired by the sensor information acquisition unit 15 and further output to the node identification unit 16. Subsequently, the node specifying unit 16 specifies the node where the terminal 10 is located from the sensor information input from the sensor information acquisition unit 15 (the position of the terminal 10 is abstracted) (S2, node) Specific step). The node is specified based on the conversion information stored in the node table 14a of the graph database 14. The node specifying process will be described later in detail with reference to the flowcharts of FIGS.

  The node ID related to the identified node is used in, for example, the location information service as described above. The identified node ID is output from the node identification unit 16 to the control unit 17. Subsequently, based on the link information stored by the link table 14b of the graph database 14 and the node specified by the node specifying unit 16 by the control unit 17, the sensor information by the sensors 11, 12, 13 in the own terminal 10 is displayed. Acquisition is controlled. Specifically, the control unit 17 acquires sensor information by the sensors 11, 12, and 13 based on the positional relationship between the identified node and another node linked by the link information. A sensor acquisition timing t, which is a time interval, is calculated (S3, control step). The calculation process of the sensor acquisition timing t will be described later in detail using the flowchart of FIG.

  Subsequently, the sensor acquisition timing t (seconds) calculated by the control unit 17 from the previous sensor information acquisition by the sensors 11, 12, 13 (from the previous sensor information acquisition instruction to the sensors 11, 12, 13). It is determined that the time indicated by has elapsed, and when this determination is made, the sensor 11, 12, 13 is instructed to acquire sensor information (S4, control step). The sensors 11, 12, and 13 that have received the instruction acquire sensor information again, and the subsequent processing (S1 to S4) is repeated. This repetition (loop) is performed until the state where the positioning of the information terminal 10 is continuously repeated, such as the operation of the information terminal 10 being stopped, is completed. The above is the overall processing executed by the information terminal 10.

  Subsequently, node specification processing (abstraction processing, S2 in FIG. 6) by the node specification unit 16 will be described with reference to the flowcharts of FIGS. In this process, first, a WiFi / BLE signal information list, which is sensor information acquired by the WiFi signal receiving unit 12 and the BLE signal receiving unit 13, is input (received) from the sensor information acquiring unit 15 (S21). Subsequently, with reference to the node table 14a, among BSSIDs included in the WiFi / BLE signal information list, BSSIDs not included in the BSSID column information of the node table 14a (unknown BSSIDs not described in the node table 14a) ) Is determined. If it is determined that there is such a BSSID, information related to the BSSID is deleted from the list (S22).

  If no element remains in the list after this processing is performed (No in S23), it is determined that the node cannot be identified from the list, and the node identification processing based on the list (abstraction) Process) is terminated. In that case, information indicating that fact (for example, NULL) is output to the control unit 17 (S24).

  If elements remain in the list after the processing of S22 is performed (Yes in S23), an average for each BSSID of RSSI associated with each BSSID included in the list is calculated (S25). ). Subsequently, the average of RSSI is used, threshold processing is performed, and the node where the terminal 10 is located is specified (S26).

  This threshold processing (S26) will be described with reference to the flowchart of FIG. First, information on th1 stored in the node table 14a is referred to in association with the BSSID related to the RSSI whose average is calculated. Subsequently, for each BSSID, the calculated RSSI average is compared with the referred th1 to determine whether the average exceeds th1 (whether the average exceeds th1) (S261). . Information related to the BSSID for which the average is determined not to exceed th1 is deleted from the WiFi / BLE signal information list. After performing this process, if no element remains in the list (No in S261), it is determined that the node cannot be specified from the list, and the node specifying process based on the list (abstraction process) ) Is terminated. In that case, information indicating that (for example, NULL) is output to the control unit 17 (S262).

  If elements remain in the list after performing the above processing (Yes in S261), it is determined whether there are two or more elements included in the list (S263). When the list includes only one element (No in S263), the node table 14a is referred to, and the node ID corresponding to the BSSID is the node where the terminal 10 is located (the user is staying). Node ID of the node) (S264).

  If there are two or more elements included in the list (Yes in S263), the two highest BSSIDs with the calculated RSSI average are extracted. Of each RSSI associated with the two extracted BSSIDs, DiffMax, which is the difference between the maximum values, is calculated. Moreover, the information of th2 stored in the node table 14a is referred to in association with the BSSID associated with the largest RSSI (maximum value) of the two BSSIDs related to the difference. The calculated difference is compared with the referenced th2, and it is determined whether or not the difference exceeds th2 (whether or not the difference exceeds th2) (S265). When it is determined that the difference exceeds th2 (Yes in S265), the node table 14a is referred to, and the node ID corresponding to the BSSID associated with the largest RSSI (maximum value) is determined by the terminal 10 itself. It is identified as the node ID of the node (node where the user is staying) located (S266).

  When it is determined that the difference does not exceed th2 (No in S265), DiffAve, which is the difference between the averages of RSSIs associated with the two BSSIDs extracted as described above, is calculated. Moreover, the information of th3 stored in the node table 14a is referred to in association with the BSSID associated with the largest RSSI average value among the two BSSIDs related to the difference. The calculated difference is compared with the referenced th3 to determine whether or not the difference exceeds th3 (whether or not the difference exceeds th3) (S267). When it is determined that the difference exceeds th3 (Yes in S267), the node table 14a is referred to, and the node ID corresponding to the BSSID associated with the largest average value of RSSI is the location of the terminal 10 itself. The node ID of the node (the node where the user is staying) is identified (S268).

  When it is determined that the difference does not exceed th3 (No in S267), it is determined that the node cannot be specified from the list, and the node specifying process (abstraction process) based on the list is ended. In that case, information indicating that (for example, NULL) is output to the control unit 17 (S262). When the node ID is specified in any one of S264, S266, and S268, the node ID is output to the control unit 17 (S269). The above is the threshold processing (S26).

  Subsequently, the processing after the threshold processing (S26) will be described with reference to FIG. In the above processing (S21 to S26), when the node (the node where the user is staying) can be specified (determined) from the WiFi / BLE signal information list (No in S27), the node specifying unit The node specification processing (abstraction processing, S2 in FIG. 6) by 16 is completed.

  If the node where the terminal 10 is located (the node where the user is staying) cannot be specified (determined) from the WiFi / BLE signal information list in the above processing (S21 to S26) (Yes in S27), sensor information Information indicating latitude and longitude, which is sensor information acquired by the GPS signal receiving unit 11, is input from the acquiring unit 15 (S28). The acquisition of latitude and longitude (GPS signal reception and positioning calculation) by the GPS signal receiving unit 11 is performed under the control of the control unit 17 to which an input indicating that the node cannot be specified from the WiFi / BLE signal information list is performed. It may be broken. That is, acquisition of sensor information by the GPS signal receiving unit 11 may be performed when a node cannot be identified from the sensor information acquired by the WiFi signal receiving unit 12 and the BLE signal receiving unit 13.

  Subsequently, the node table 14a is referred to, and information on the central latitude and longitude and the radius (m) of each node is acquired. Based on the information, the node specifying unit 16 specifies the node (the node where the user is staying) where the terminal 10 is located from the latitude and longitude indicated by the information acquired by the GPS signal receiving unit 11 ( S29). The identified node ID is output to the control unit 17. The above is the node specifying process by the node specifying unit 16.

Subsequently, the sensor acquisition timing t calculation process (S3 in FIG. 6) by the control unit 17 will be described with reference to the flowchart in FIG. In this process, the node ID indicating the node specified by the node specifying unit 16 is input (S31). Subsequently, referring to the link table 14b, a node (adjacent node) adjacent to the node (staying node) specified by the node specifying unit 16 is specified. Subsequently, the movement cost cost is calculated for each adjacent node by the following equation.

以上が、制御部１７によるセンサ取得タイミングｔの算出処理である。 Subsequently, the minimum movement cost min_cost among all the adjacent nodes is determined (S33). Subsequently, the sensor acquisition timing t (seconds) is calculated by the following equation (S34).

The above is the calculation process of the sensor acquisition timing t by the control unit 17.

  As described above, in this embodiment, a node that is a position abstracted as the position of the information terminal 10 is specified. The node is specified based on sensor information acquired by the sensors 11, 12, and 13 of the information terminal 10. In the present embodiment, acquisition of sensor information by the information terminal 10 is controlled based on the node specified as the node where the information terminal 10 is located. Therefore, sensor information can be acquired so as to suppress wasteful power consumption according to the node where the information terminal 10 is located. That is, according to the present embodiment, it is possible to reduce power consumption of the information terminal 10 while appropriately performing continuous positioning of the information terminal 10.

  Specifically, the sensor acquisition timing may be determined as described above. According to this configuration, the time interval for acquiring sensor information by the information terminal 10 can be made appropriate. For example, when the node where the information terminal 10 is located is adjacent to the adjacent node, that is, when the node where the user is located cannot be changed immediately, the time interval is increased, and the power from acquiring unnecessary sensor information is increased. Consumption can be prevented. On the other hand, when the node where the information terminal 10 is located and the adjacent node are close to each other, that is, when the node where the user is located can be changed immediately, the time interval is reduced and the necessary position measurement is performed. be able to. Thereby, the power consumption of the information terminal 10 can be reduced while appropriately performing continuous positioning of the information terminal 10.

  Further, as described above, in the calculation of the sensor acquisition timing, the user's stay time and the user's moving speed at each node may be used. According to these configurations, the time interval can be made more appropriate. However, when the sensor acquisition timing can be determined without using these pieces of information, it is not always necessary to use these pieces of information.

  As described above, the type of sensor information may be determined based on the characteristics of a node adjacent to the node where the information terminal 10 is located (for example, the node is either an indoor node or an outdoor node). According to this configuration, the type of sensor from which sensor information is acquired can be made appropriate. That is, it is possible to acquire sensor information that can easily identify the node where the information terminal 10 is located. Accordingly, it is possible to prevent unnecessary sensor information from being acquired while appropriately performing continuous positioning of the information terminal, and to reduce power consumption of the information terminal.

  Further, as described above, the node where the information terminal 10 is located may be specified from the average and difference of the reception strengths of the short-range wireless communication radio waves. According to this configuration, it is possible to appropriately identify the node where the information terminal 10 is located based on the reception strength of the short-range wireless communication radio wave.

  In the above-described embodiment, the position positioning system is the information terminal 10 itself that is a position positioning target. However, the position positioning system does not necessarily have to be the information terminal 10. For example, when the information terminal 10 has a mobile communication function, the position positioning system is a position positioning server that can send and receive information to and from the information terminal 10 via the mobile communication network. There may be. That is, it may be implemented by a server client model. In this case, the information terminal includes the sensors 11, 12, and 13 as in the present embodiment. The positioning server receives sensor information acquired by the sensors 11, 12, and 13 from the information terminal, specifies a node based on the received sensor information, and controls acquisition of sensor information in the information terminal. In that case, the position measurement server includes functional units corresponding to the graph database 14, the sensor information acquisition unit 15, the node specification unit 16, and the control unit 17 in the present embodiment. Further, some of these components are provided in the information terminal, and the information terminal and the positioning device may constitute a position positioning system.

  In the embodiment described above, the sensor information is based on GPS, WiFi, and BLE. However, any information may be used as long as the node can be specified. For example, NFC (Near Field Communication) may be used as near field communication. Information obtained by a gyro sensor, an acceleration sensor, a geomagnetic sensor, or the like may be used as sensor information.

  In the embodiment described above, the area of the node is circular, and is stored in the node table 14a, which is used to identify the node from information indicating latitude and longitude, which is sensor information acquired by the GPS signal receiving unit 11. The conversion information was the central latitude and longitude and the radius (m). However, the shape of the node area and the conversion information stored in the node table 14a are not necessarily limited to those described above. For example, the node shape may be rectangular. In this case, the conversion information stored in the node table 14a may be, for example, information indicating latitude and longitude indicating the positions of the four corners of the rectangle.

  In the above-described embodiment, the user's moving speed and the user's staying time at each node used for determining the sensor acquisition timing are obtained based on the user's past results (history) and the information terminal 10 based on the results. You may use what was calculated. For example, the walking speed varies from user to user, so by using the user's past average walking speed, in the case of a fast-moving user, the time until acquisition of the next sensor information is shortened, and the node is appropriately specified. Is possible.

  Further, the graph database 14 stores information indicating the staying time of the user at each node according to the user's attribute, and the control unit 17 is also based on the staying time of the user according to the user's attribute of the information terminal 10. Thus, the time interval for acquiring the sensor information may be determined. For example, you may memorize | store a user's stay time according to a user's sex and age.

  It is predicted that the average staying time of the node greatly depends on the user attribute of gender. For example, at a shopping mall for ladies in a shopping mall, women tend to stay for a long time, but men do not stop there. If it is determined that the user has stayed at such a node, the next sensor acquisition timing is set longer for women and shorter for men. It may be changeable.

  When the information terminal 10 inputs information indicating a user attribute by a user operation or the like, the staying time of the user according to the user attribute can be used. According to this structure, the said time interval can be made more suitable according to a user's attribute.

  In addition, the position positioning system may further include a node link generation unit that automatically generates information stored in the graph database 14. The node link generation unit acquires a plurality of sensor information and information indicating the latitude and longitude of the position where the sensor information is acquired, and generates information stored in the graph database 14 based on the acquired information. Node link generation means. For example, the node link generation unit may be provided in the position positioning server described above, or may be provided in the information terminal 10. Specifically, the node link generation unit generates information as follows.

  The information terminal 10 acquires sensor information with the sensors 11, 12, and 13 at a high frequency. Moreover, the latitude and longitude of the information terminal 10 are measured at the timing when the sensor information is acquired. For the measurement of latitude and longitude, for example, GPS tracking tracking is used, and indoor measurement is three-point survey using RSSI acquired from a short-range wireless communication device. Further, in order to obtain the height difference, the altitude at the position is measured from the atmospheric pressure measured by the atmospheric pressure sensor provided in the GPS or the information terminal 10.

  The node link generation unit acquires the information acquired as described above from the information terminal 10 as a time-series history. This acquisition may be performed from a plurality of information terminals 10 (a plurality of users). The node link generation unit specifies the flow line of the user from the history of the information and acquires the user's stay point (where the user has stopped for a long time). The node link generation unit collects the stay points of a plurality of users and performs clustering to specify the stay area (where the user tends to stop) on the area. A known unsupervised learning algorithm such as the X-means method can be applied to the clustering. Note that the node link generation unit may identify a stay area (corresponding to one cluster) by performing clustering on each latitude and longitude instead of the stay point.

  The node link generation unit generates information stored in the graph database 14 using the specified stay area as a node. In that case, the conversion information stored in the node table 14a is generated as follows. The node ID is set so as not to overlap between nodes. The central latitude and longitude are obtained by averaging the latitude and longitude included in the stay area. The radius (m) is determined based on the central latitude and longitude so as to include the latitude and longitude included in the stay area. The average stay time is used when the stay time can be determined from the history of time series. Alternatively, a preset value may be used as the average stay time. The BSSID is the BSSID having the largest number among the BSSIDs indicated by the sensor information acquired simultaneously with the latitude and longitude included in the staying area. If there is no BSSID indicated by the sensor information acquired at the same time as the latitude and longitude included in the stay area (WiFi / BLE signal information list), no BSSID is set. For th1, th2, and th3, preset values are used.

  The link information stored in the link table 14b is generated based on a time series history. For example, a link is set between staying areas (between nodes) where a certain number of movements between staying areas are made. The distance (m) between the centers and the height difference (m) are obtained by the central latitude and longitude and the altitude described above.

  The generation of information stored in the graph database 14 by the node link generation unit may be performed as follows. For example, as an advance preparation, when an area where a node is not set includes an indoor area, a number of short-range wireless communication devices such as WiFi access points and BLE devices are installed in the indoor area at intervals of several meters, for example. Then, the graph database 14 is generated temporarily as described above.

  Then, after the nodes are generated, the short-range wireless communication devices are rearranged so as to correspond to the individual nodes. In the preliminary preparation stage, many short-range wireless communication devices are installed indoors at intervals of several meters, but this time, one short-range wireless communication device is installed in one staying area (node). Then, the information stored in the graph database 14 is again generated by the node link generation unit to obtain information after rearrangement.

  According to said structure, the information memorize | stored in the graph database 14 can be produced | generated automatically.

  DESCRIPTION OF SYMBOLS 10 ... Information terminal, 11 ... GPS signal receiving part, 12 ... WiFi signal receiving part, 13 ... BLE signal receiving part, 14 ... Graph database, 14a ... Node table, 14b ... Link table, 15 ... Sensor information acquisition part, 16 ... Node identification unit, 17 ... control unit, 101 ... CPU, 102 ... RAM, 103 ... ROM, 104 ... operation unit, 105 ... display, 106 ... GPS reception module, 107 ... GPS reception antenna, 108 ... Near field communication module 109: Short-range wireless communication antenna.

Claims (9)

A position positioning system that estimates the position of an information terminal including a sensor that acquires sensor information used to estimate the position of the terminal.
A graph database for storing conversion information for specifying nodes that are positions abstracted from sensor information acquired by the sensors, and link information indicating links between the nodes;
Sensor information acquisition means for acquiring sensor information acquired by the sensor of the information terminal;
Based on the conversion information stored by the graph database, from the sensor information acquired by the sensor information acquisition means, node specifying means for specifying the node where the information terminal is located;
Control means for controlling acquisition of sensor information by the information terminal based on the link information stored by the graph database and the node specified by the node specifying means;
Positioning system equipped with. The graph database further stores information indicating a positional relationship between nodes as the link information,
The control means includes sensor information by the information terminal based on a positional relationship between the node specified by the node specifying means indicated by the link information stored by the graph database and another node linked to the node. The position positioning system according to claim 1, wherein a time interval of acquisition of is determined.   The position positioning system according to claim 2, wherein the control means determines a time interval for acquiring sensor information by the information terminal based on a preset moving speed of the user of the information terminal. The graph database further stores information indicating a user's stay time at each node as the link information,
The control means determines a time interval for acquiring the sensor information by the information terminal based on the stay time of the user at the node specified by the node specifying means indicated by the link information stored by the graph database. The position positioning system according to any one of claims 1 to 3. The graph database stores information indicating a user's stay time at each node according to the user's attributes,
5. The position positioning system according to claim 4, wherein the control unit determines a time interval for acquiring sensor information by the information terminal based on a user's stay time corresponding to a user attribute of the information terminal. The information terminal includes a plurality of types of the sensors,
The control means is a sensor that acquires sensor information in the information terminal based on the characteristics of another node linked to the node specified by the node specifying means indicated by the link information stored by the graph database. The position positioning system according to any one of claims 1 to 5, wherein the position type is determined. The sensor acquires information indicating reception intensity of radio waves for short-range wireless communication as sensor information,
The sensor information acquisition means acquires information indicating reception intensity at a plurality of timings,
The position positioning system according to any one of claims 1 to 6, wherein the node specifying unit specifies a node where the information terminal is located from an average and a difference of a plurality of reception strengths.   Node link generating means for acquiring a plurality of sensor information and information indicating the latitude and longitude of the position where the sensor information is acquired, and generating information stored in the graph database based on the acquired information The position positioning system as described in any one of Claims 1-7 provided. Conversion information for estimating the position of an information terminal including a sensor that acquires sensor information used for estimating the position of the terminal itself and specifying a node that is a position abstracted from the sensor information acquired by the sensor; And a positioning method that is an operation method of the positioning system including a graph database that stores link information indicating links between the nodes,
A sensor information acquisition step of acquiring sensor information acquired by a sensor of the information terminal;
Based on the conversion information stored by the graph database, from the sensor information acquired in the sensor information acquisition step, a node specifying step for specifying a node where the information terminal is located;
A control step for controlling acquisition of sensor information by the information terminal based on the link information stored by the graph database and the node specified in the node specifying step;
Positioning method including

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