Positioning system, positioning method, terminal device, and non-transitory storage medium

Abstract

[Problem] To provide a setup enabling further improvement in positioning accuracy. [Solution] This positioning system includes a first terminal device that sets two reference stations and one or more correction stations from among three or more beacons associated with an area in which the first terminal device is located, sets a correction value for radio wave intensity for each of the one or more correction stations, and generates calibration information including predetermined information; and a second terminal device that refers to the calibration information and measures the position of the second terminal device on the basis of the radio wave intensity of the beacon signals received from the two reference stations and the radio wave intensity after correction based on the correction values of the beacon signals received from the one or more correction stations, the reference stations and the correction stations being associated with the area in which the second terminal device is located.

Description

Positioning system, positioning method, terminal device, and non-transitory storage medium

[0001] The present invention relates to a positioning system, a positioning method, a terminal device, and a non-transitory storage medium.

[0002] In recent years, positioning technologies have been utilized in various fields. One known positioning technology uses satellite signals such as GNSS (Global Navigation Satellite System). However, the positioning accuracy decreases in locations where it is difficult to receive satellite signals, such as indoors. Therefore, a technology for performing three-point positioning using received radio wave intensity of a beacon signal has been proposed, such as the technology disclosed in Patent Literature 1.

[0003] Japanese Patent Application Laid-Open No. 2019-100708

[0004] However, even with the technology disclosed in Patent Document 1, the positioning accuracy may be reduced in locations where the radio wave strength of the beacon signal is attenuated due to the influence of multipath or obstacles.

[0005] Therefore, the present invention has been made in consideration of the above problems, and an object of the present invention is to provide a mechanism that can further improve positioning accuracy.

[0006] In order to solve the above problem, according to one aspect of the present invention, a positioning system is provided, comprising a first terminal device, a second terminal device, and a plurality of beacons, wherein the first terminal device sets two reference stations and one or more correction stations from three or more beacons associated with the area in which the first terminal device is located based on the radio wave strength of a plurality of beacon signals received from the plurality of beacons, sets a correction value for the radio wave strength for each of the one or more correction stations, and generates calibration information including specified information, and the second terminal device refers to the calibration information generated by the first terminal device and measures the position of the second terminal device based on the radio wave strength of the beacon signals received from the two reference stations associated with the area in which the second terminal device is located, and the radio wave strength corrected based on the correction value of the beacon signals received from one or more correction stations.

[0007] The calibration information may include information indicating the area in which the first terminal device is located, information indicating the set reference station and correction station, and information indicating the set correction value.

[0008] The first terminal device may set the two beacons with the strongest radio wave strength among the radio wave strengths of the multiple beacon signals received from the multiple beacons as the reference stations, and set one or more other beacons as the correction stations.

[0009] The first terminal device may set the difference between the statistical value of the radio wave strength of the beacon signal received from the two reference stations and the radio wave strength of the beacon signal received from the correction station as the correction value of the correction station.

[0010] The second terminal device may calculate the corrected radio wave strength by adding the correction value set in the correction station to the radio wave strength of the beacon signal received from the correction station.

[0011] The second terminal device may measure the position of the second terminal device further based on the position information of the reference station and the correction station.

[0012] The first terminal device may set a first threshold based on a statistical value of the radio wave strength of the beacon signal received from the two reference stations, the calibration information may include the first threshold, and the second terminal device may determine the area in which the second terminal device is located based on the first threshold included in the calibration information.

[0013] The second terminal device may determine that the second terminal device is located in the area in which the two beacons that are the source of the beacon signal and whose radio wave strength is stronger than the first threshold are the two reference stations.

[0014] The first terminal device may accept input of information indicating the area in which the first terminal device is located.

[0015] The first terminal device and the second terminal device may use the radio wave strength of the beacon signal received from the beacon, which is stronger than a second threshold, as the radio wave strength of the beacon signal received from the beacon.

[0016] The first terminal device and the second terminal device may set the second threshold based on the radio wave strength of one or more beacon signals with the strongest radio wave strength among the radio wave strengths of multiple beacon signals received from the beacon during a specified period.

[0017] The positioning system may further include a storage device, wherein the first terminal device transmits the generated calibration information to the storage device, the storage device stores the calibration information received from the first terminal device, and the second terminal device refers to the calibration information stored in the storage device.

[0018] The second terminal device may store the calibration information generated by the first terminal device and refer to the stored calibration information.

[0019] The first terminal device and the second terminal device may be the same device.

[0020] In addition, in order to solve the above problem, according to another aspect of the present invention, a positioning method is provided, which includes: a plurality of beacons transmitting beacon signals; a first terminal device setting two reference stations and one or more correction stations from three or more beacons associated with the area in which the first terminal device is located based on the radio wave intensities of the plurality of beacon signals received from the plurality of beacons, and setting a correction value for the radio wave intensity for each of the one or more correction stations; the first terminal device generating calibration information including predetermined information; and a second terminal device referring to the calibration information generated by the first terminal device, and measuring the position of the second terminal device based on the radio wave intensities of the beacon signals received from the two reference stations associated with the area in which the second terminal device is located, and the radio wave intensity corrected based on the correction value of the beacon signal received from one or more correction stations.

[0021] In addition, in order to solve the above problem, according to another aspect of the present invention, there is provided a terminal device comprising: a beacon signal receiving unit that receives a beacon signal transmitted from a beacon; and a control unit that measures the position of the terminal device based on the beacon signal received by the beacon signal receiving unit, wherein the control unit sets two reference stations and one or more correction stations from three or more beacons associated with an area in which the terminal device is located based on the radio wave intensities of multiple beacon signals received from multiple beacons, sets a correction value for the radio wave intensity for each of the one or more correction stations, generates calibration information including predetermined information, refers to the calibration information, and measures the position of the terminal device based on the radio wave intensities of the beacon signals received from the two reference stations associated with the area in which the terminal device is located, and the radio wave intensity corrected based on the correction value of the beacon signal received from one or more correction stations.

[0022] In addition, in order to solve the above problem, according to another aspect of the present invention, a computer that controls a terminal device having a beacon signal receiving unit that receives a beacon signal transmitted from a beacon is made to function as a control unit that measures the position of the terminal device based on the beacon signal received by the beacon signal receiving unit, and the control unit sets two reference stations and one or more correction stations from three or more beacons associated with the area in which the terminal device is located based on the radio wave intensities of multiple beacon signals received from multiple beacons, sets a correction value for the radio wave intensity for each of the one or more correction stations, generates calibration information including predetermined information, refers to the calibration information, and measures the position of the terminal device based on the radio wave intensities of the beacon signals received from the two reference stations associated with the area in which the terminal device is located, and the radio wave intensity corrected based on the correction value of the beacon signal received from one or more correction stations.

[0023] As described above, according to the present invention, a mechanism capable of further improving positioning accuracy is provided.

[0024] FIG. 1 is a block diagram showing an example of the configuration of a positioning system 1 according to an embodiment of the present invention. FIG. 2 is a diagram for explaining the removal of multipath by a terminal device 20 according to the present embodiment. FIG. 3 is a diagram for explaining a specific example of calibration according to the present embodiment. FIG. 4 is a diagram for explaining a specific example of positioning according to the present embodiment. FIG. 5 is a flowchart showing an example of the flow of processing related to calibration executed by the terminal device 20 according to the present embodiment. FIG. 6 is a flowchart showing an example of the flow of processing related to positioning executed by the terminal device 20 according to the present embodiment. FIG. 7 is a block diagram showing an example of the hardware configuration of an information processing device according to the present embodiment.

[0025] Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings. In this specification and drawings, components having substantially the same functional configurations are designated by the same reference numerals, and redundant explanations will be omitted.

[0026] <1. Summary of Issues> Even when three-point positioning is performed using radio wave strength, the received radio wave strength of the beacon signal is attenuated in blind spots caused by multipath or obstacles, resulting in reduced positioning accuracy. One example of a method for preventing a reduction in positioning accuracy is to install a beacon in a location with good visibility, such as on the warehouse ceiling, when performing positioning inside a warehouse. However, such installation requires working at a height, which is dangerous, and it is difficult to install the beacon accurately in a location with good visibility.

[0027] In addition to radio wave strength, there are also technologies that perform three-point positioning using the direction of arrival of radio waves or the time difference of arrival of radio waves. However, introducing such technologies can be difficult because additional construction work is required, such as the installation of dedicated antennas and equipment.

[0028] Therefore, one embodiment of the present invention performs three-point positioning by removing multipath interference and correcting the received radio wave intensity attenuated by the influence of obstacles. This configuration makes it possible to easily install and deploy beacons and improve positioning accuracy.

[0029] An embodiment of the present invention will be described in detail below.

[0030] 1 is a block diagram showing an example of the configuration of a positioning system 1 according to an embodiment of the present invention. As shown in FIG. 1, the positioning system 1 includes a plurality of beacons 10, a plurality of terminal devices 20, and a server 30.

[0031] (Beacon 10) The beacon 10 is a device that periodically transmits a beacon signal. The beacon 10 is fixed at a predetermined position. The beacon 10 is powered by, for example, a built-in battery.

[0032] As shown in FIG. 1, the beacon 10 includes a beacon signal transmitter 11 .

[0033] The beacon signal transmitter 11 periodically transmits a beacon signal that complies with any wireless communication standard, such as Bluetooth (registered trademark), BLE (Bluetooth Low Energy (registered trademark)), Wi-Fi (registered trademark), Zigbee (registered trademark), or UWB (Ultra-Wide Band).

[0034] (Terminal Device 20) The terminal device 20 is a device operated by a user. The terminal device 20 is a portable device such as a smartphone or a tablet terminal.

[0035] As shown in FIG. 1, the terminal device 20 includes a beacon signal receiving unit 21, a communication unit 22, a storage unit 23, and a control unit 24.

[0036] The beacon signal receiving unit 21 receives a beacon signal transmitted from the beacon 10. The beacon signal receiving unit 21 measures the radio wave intensity when receiving the beacon signal. Note that the radio wave intensity of the beacon signal received from the beacon 10 will also be referred to as the radio wave intensity of the beacon 10 hereinafter.

[0037] The communication unit 22 communicates with the server 30 via the network 9. The network 9 may include any network such as the Internet, a cellular communication network, a local area network (LAN), or Wi-Fi.

[0038] The storage unit 23 temporarily or permanently stores information for the operation of the terminal device 20. For example, the storage unit 23 temporarily stores the radio wave intensity measured by the beacon signal receiving unit 21.

[0039] The control unit 24 controls the overall operation of the terminal device 20. For example, the control unit 24 controls calibration (to be described later) and positioning (to be described later).

[0040] (Server 30) The server 30 is a storage device that stores information for the operation of the terminal device 20. The server 30 stores information collected from the terminal device 20 and transmits the information to the terminal device 20 as necessary.

[0041] As shown in FIG. 1 , the server 30 includes a communication unit 31 , a storage unit 32 , and a control unit 33 .

[0042] The communication unit 31 communicates with the terminal device 20 via the network 9 .

[0043] The storage unit 32 stores information for the operation of the terminal device 20. Examples of information stored in the storage unit 32 are position information of the beacons 10 and calibration information (described later). The position information of the beacons 10 indicates the coordinates (two-dimensional coordinates or three-dimensional coordinates) at which all the beacons 10 included in the positioning system 1 are installed.

[0044] The control unit 33 controls the overall operation of the server 30 .

[0045] 2 is a diagram for explaining the elimination of multipath signals by the terminal device 20 according to this embodiment. As shown in FIG. 2, the beacon 10 is installed on, for example, a pillar P in a warehouse and transmits a beacon signal.

[0046] The terminal device 20 receives the beacon signal transmitted from the beacon 10 and measures the radio wave intensity. In addition to direct waves (i.e., valid radio waves), the terminal device 20 may receive reflected waves (i.e., ineffective radio waves) that have arrived after being reflected by baggage C, floor F, or the like. For example, the terminal device 20 receives a direct wave of −62 dBm, a reflected wave of −85 dBm that has arrived after being reflected by baggage C, and a reflected wave of −78 dBm that has arrived after being reflected by floor F.

[0047] The terminal device 20 uses the radio wave strength of the beacon signal received from the beacon 10 that is stronger than the filter threshold as the radio wave strength of the beacon signal received from the beacon 10. For example, if the filter threshold is -67 dBm, the terminal device 20 uses -62 dBm, which is stronger than -67 dBm, as the radio wave strength of the beacon 10. On the other hand, the beacon 10 ignores -85 dBm and -78 dBm, which are weaker than -67 dBm. That is, the terminal device 20 performs calibration, positioning, etc., assuming that the radio wave strength of the beacon 10 is -62 dBm.

[0048] Because the radio wave strength differs greatly between direct waves and reflected waves, this configuration can eliminate multipath interference. The terminal device 20 can then perform calibration or positioning based on the radio wave strength of the direct waves. As a result, the positioning accuracy can be improved.

[0049] The terminal device 20 may set the filter threshold based on the radio wave strength of one or more beacon signals with the strongest radio wave strength among the radio wave strengths of multiple beacon signals received from the beacon 10 over a predetermined period. For example, the terminal device 20 may sample and measure the radio wave strength of the beacon signals received from the beacon 10 over the most recent two seconds, and set the filter threshold to −67 dBm, which is lower than the strongest radio wave strength of −62 dBm over those two seconds and −5 dBm. Then, over the next two seconds, the terminal device 20 considers beacon signals with radio wave strength weaker than the filter threshold as reflected waves and removes them, and performs calibration or positioning using beacon signals with radio wave strength stronger than the filter threshold.

[0050] According to this configuration, it is possible to appropriately set / update the filter threshold and appropriately remove multipath.

[0051] The values ​​"-5 dBm" and "2 seconds" given above are merely examples, and any other values ​​may be used.

[0052] The filter threshold corresponds to the second threshold in this embodiment.

[0053] (Calibration) The terminal device 20 sets two reference stations and one or more correction stations from three or more beacons 10 associated with the area in which the terminal device 20 is located, based on the radio wave intensities of multiple beacon signals received from multiple beacons 10. An area is a range in which beacon signals can be received from as many beacons 10 as necessary for positioning. The reference station is a beacon 10 that serves as a reference when determining the area in which the terminal device 20 is located and when the terminal device 20 performs positioning. The correction station is a beacon 10 that is referenced in addition to the reference station when the terminal device 20 performs positioning. By setting a reference station and a correction station for each area, it becomes possible to perform positioning in a manner suited to the attenuation of radio wave intensity, which differs from area to area, and it becomes possible to improve positioning accuracy.

[0054] Typically, all beacons 10 associated with an area are set to either the reference station or the correction station of the area. However, it is not necessary that all beacons 10 associated with an area are set to either the reference station or the correction station of the area. Among the beacons 10 associated with an area, there may be beacons 10 that are not set to either the reference station or the correction station of the area.

[0055] The terminal device 20 sets a correction value for radio wave intensity for each of one or more correction stations. The correction value is used to correct the radio wave intensity from the correction station when the terminal device 20 performs positioning. With this configuration, the radio wave intensity from the correction station, which may be attenuated by obstacles such as a pillar P or luggage C, can be appropriately corrected and used for positioning, thereby improving positioning accuracy.

[0056] Then, the terminal device 20 generates calibration information including information indicating the area in which the terminal device 20 is located, information indicating the set reference station and correction station, and information indicating the set correction value. The calibration information includes predetermined information and is referenced when the terminal device 20 performs positioning. With this configuration, by performing calibration in advance, it is possible to improve the accuracy of subsequent positioning.

[0057] A specific example of calibration will be described below with reference to FIG.

[0058] 3 is a diagram for explaining a specific example of calibration according to this embodiment. In FIG. 3, a top view of a terminal device 20 performing calibration inside a warehouse in which multiple beacons 10 (10A to 10F) are placed on multiple pillars P, respectively, and areas A1 and A2 are defined is shown.

[0059] An example of the calibration information generated in the example shown in FIG. 3 is shown in Table 1 below.

[0060]

[0061] As shown in Table 1, the calibration information includes area information, reference station information, and information on one or more correction stations.

[0062] Area information is information for identifying an area. The area information includes IDs of three or more beacons 10 associated with the area. An area can be a space partitioned by three or more beacons 10 associated with the area. Beacons 10A, 10B, 10D, and 10E are associated with area A1. Beacons 10B, 10C, 10E, and 10F are associated with area A2.

[0063] The reference station information is information about two reference stations set in the area. The reference station information includes the IDs of the two beacons 10 set as reference stations, the average radio wave strength of the two beacons 10 set as reference stations, and an area determination threshold. The area determination threshold is used by the terminal device 20 to determine the location area when positioning. The area determination threshold is an example of a first threshold in this embodiment.

[0064] The correction station information is information about each of one or more correction stations set in the area. The correction station information includes the ID of the beacon 10 set as the correction station, the radio wave intensity of the beacon 10, and the correction value set for the beacon 10.

[0065] Of the calibration information shown in Table 1, the area information is set manually, and the other information is set automatically during calibration by the terminal device 20.

[0066] 3, area A1 is an area to which beacons 10A, 10B, 10D, and 10E are associated. Calibration for area A1 can be performed with the terminal device 20 located at the center of area A1.

[0067] The terminal device 20 accepts input of information indicating the area in which the terminal device 20 is located. For example, the terminal device 20 accepts input of information indicating that the terminal device 20 is located in area A1 from the user, and sets the IDs of the beacons 10A, 10B, 10D, and 10E associated with area A1 as the ID of the area.

[0068] The location area of ​​the terminal device 20 may be input, for example, via a touch panel or the like mounted on the terminal device 20. Alternatively, the location area of ​​the terminal device 20 may be input, for example, using RFID (Radio Frequency Identification). That is, an RFID tag storing the ID of the area may be placed in the area, and the terminal device 20 may identify the location area by reading the RFID tag.

[0069] The terminal device 20 located in the center of the area A1 receives direct waves from the beacons 10A and 10D. The radio wave strength of the beacon 10A is −62 dBm, and the radio wave strength of the beacon 10D is −62 dBm.

[0070] On the other hand, the terminal device 20 located at the center of the area A1 receives reflected waves from the beacons 10B and 10E due to the influence of the pillar P. As a result, the radio wave strength of the beacon 10B is −82 dBm, and the radio wave strength of the beacon 10E is −83 dBm.

[0071] The terminal device 20 sets the two beacons 10 with the strongest radio wave intensities as reference stations among the radio wave intensities of the multiple beacon signals received from the multiple beacons 10, and sets one or more other beacons 10 as correction stations. With respect to area A1, the terminal device 20 sets the beacons 10A and 10D as reference stations, and sets the beacons 10B and 10E as correction stations.

[0072] Then, the terminal device 20 sets the difference between the statistical value of the radio wave strength of the beacon signals received from the two reference stations and the radio wave strength of the beacon signal received from the correction station as the correction value of the correction station. The statistical value is typically an average value, but may be a maximum value, a minimum value, or the like. With respect to area A1, the terminal device 20 sets +20 dBm, which is obtained by subtracting -82 dBm, which is the radio wave strength of the beacon 10B, from -62 dBm, which is the average value of the radio wave strength of the beacons 10A and 10D, as the correction value of the beacon 10B. On the other hand, the terminal device 20 sets +21 dBm, which is obtained by subtracting -83 dBm, which is the radio wave strength of the beacon 10E, from -62 dBm, which is the average value of the radio wave strength of the beacons 10A and 10D, as the correction value of the beacon 10E.

[0073] The terminal device 20 sets the area determination threshold based on the statistical value of the radio wave strength of the beacon signals received from the two reference stations. For example, the terminal device 20 sets a value obtained by weakening the statistical value as the area determination threshold. The statistical value is typically an average value, but may also be a maximum value, minimum value, or the like. With respect to area A1, the terminal device 20 sets the area determination threshold to -69 dBm, which is obtained by adding -7 dBm to -62 dBm, which is the average value of the radio wave strength of the beacons 10A and 10D. Note that this value of "-7 dBm" is merely an example, and any other value may be used.

[0074] Through the above-described processing, the terminal device 20 generates calibration information for area A1 shown in Table 1. The terminal device 20 also performs similar processing for area A2 to generate calibration information for area A2 shown in Table 1.

[0075] The terminal device 20 transmits the generated calibration information to the server 30, and the server 30 stores the information.

[0076] (Positioning) The terminal device 20 measures its position by referring to calibration information generated in advance and stored by the server 30. Specifically, the terminal device 20 measures its position based on the radio wave strength of beacon signals received from two reference stations associated with the area in which the terminal device 20 is located, and the radio wave strength corrected based on a correction value of the beacon signal received from one or more correction stations. That is, the terminal device 20 measures its position based on the radio wave strength of the reference station from which direct waves are assumed to be received, and the radio wave strength of the correction station corrected by a correction value for attenuation due to obstacles such as the pillar P or the luggage C. With this configuration, it is possible to eliminate the influence of attenuation due to obstacles such as the pillar P or the luggage C, thereby improving positioning accuracy.

[0077] A specific example of positioning will be described below with reference to FIG.

[0078] Fig. 4 is a diagram for explaining a specific example of positioning according to this embodiment. In the example shown in Fig. 4, positioning is performed in the same environment as the environment shown in Fig. 3. The terminal device 20 performs positioning by referring to the calibration information shown in Table 1. In the following, it is assumed that the terminal device 20 is located in the center of area A1.

[0079] First, the terminal device 20 determines the area in which the terminal device 20 is located based on the area determination threshold included in the calibration information. Specifically, the terminal device 20 determines that the terminal device 20 is located in an area in which two beacons 10 that are transmission sources of beacon signals whose radio wave intensity is stronger than the area determination threshold serve as two reference stations.

[0080] As described above with reference to Figure 3, when the terminal device 20 is located in area A1, the radio wave intensities of the beacons 10A, 10B, 10D, and 10E are -62 dBm, -82 dBm, -62 dBm, and -83 dBm, respectively. Area A1 is associated with the beacons 10A and 10D, which have radio wave intensities stronger than the area determination threshold of -69 dBm for area A1. On the other hand, area A2 is not associated with the beacons 10A and 10D, which have radio wave intensities stronger than the area determination threshold of -69 dBm for area A2. Therefore, it can be determined that the terminal device 20 is located in area A1.

[0081] Thereafter, the terminal device 20 performs positioning based on the calibration information for the area A1.

[0082] First, the terminal device 20 calculates the corrected radio wave strength by adding the correction value set in the correction station to the radio wave strength of the beacon signal received from the correction station. As shown in Fig. 4, the terminal device 20 calculates the corrected radio wave strength of the beacon 10B by adding +20 dBm, which is the correction value of the beacon 10B, to the radio wave strength of -82 dBm of the beacon 10B, which is the correction station. Similarly, the terminal device 20 calculates the corrected radio wave strength of the beacon 10E by adding +21 dBm, which is the correction value of the beacon 10E, to the radio wave strength of -83 dBm of the beacon 10E, which is the correction station.

[0083] The terminal device 20 then measures its location based on the radio wave strength of the beacons 10A and 10D, which are the reference stations, and the corrected radio wave strength of the beacons 10B and 10E, which are the correction stations. Because these radio wave strengths are all the same, −62 dBm, it is possible to determine that the terminal device 20 is located in the center of area A1.

[0084] Here, the terminal device 20 may measure the position of the terminal device 20 further based on the position information of the reference station and the correction station. In detail, the terminal device 20 may measure the position of the terminal device 20 by three-point positioning based on the position information of the beacons 10 and the radio wave strength of each beacon 10 (in the case of a correction station, the radio wave strength after correction). With this configuration, it is possible to identify the coordinates where the terminal device 20 is located.

[0085] The terminal device 20 can measure its own position through the processing described above. Although the case where the terminal device 20 is located in area A1 has been described above, the terminal device 20 can also measure its own position in the same way when it is located in area A2.

[0086] (Method of Referencing Calibration Information) The terminal device 20 that performs calibration is an example of a first terminal device, while the terminal device 20 that performs positioning is an example of a second terminal device.

[0087] The terminal device 20 that performs calibration and the terminal device 20 that performs positioning may be the same device. In this case, the terminal device 20 generates and stores calibration information and uses it for subsequent positioning. The terminal device 20 may omit transmitting the calibration information to the server 30 and receiving the calibration information from the server 30.

[0088] The terminal device 20 that performs calibration and the terminal device 20 that performs positioning may be different devices. In this case, the calibrated terminal device 20 transmits calibration information to the server 30, and the server 30 stores the calibration information received from the terminal device 20. Then, the terminal device 20 that performs positioning refers to the calibration information stored in the server 30.

[0089] The terminal device 20 may access the server 30 every time it performs positioning and refer to the calibration information stored in the server 30. With this configuration, it is possible to always refer to the latest calibration information.

[0090] Alternatively, the terminal device 20 may download and store the calibration information stored in the server 30, and refer to the stored calibration information when performing positioning. This configuration reduces the communication load and enables positioning even in an offline state.

[0091] Similarly, the position information of the beacon 10 may be stored in the server 30 and referred to each time positioning is performed, or may be downloaded to the terminal device 20 and referred to offline.

[0092] 4. Processing Flow> (Calibration) FIG. 5 is a flowchart showing an example of the flow of processing related to calibration executed by the terminal device 20 according to this embodiment.

[0093] As shown in FIG. 5, first, the terminal device 20 accesses the server 30 and acquires the location information of the beacon 10 (step S101).

[0094] Next, the terminal device 20 sets a location area (step S103). For example, the terminal device 20 sets a location area input by the user. At this time, it is desirable that the user position the terminal device 20 in the center of the location area.

[0095] Next, the terminal device 20 receives beacon signals from a plurality of surrounding beacons 10 and measures the radio wave intensity (step S105).

[0096] Next, the terminal device 20 removes multipath signals (step S107). For example, the terminal device 20 sets and uses a filter threshold to select radio wave strengths stronger than the filter threshold. The radio wave strength hereinafter refers to the radio wave strength after multipath signals have been removed.

[0097] Next, the terminal device 20 sets two reference stations and one or more correction stations for the location area based on the radio wave intensity of the beacon 10 associated with the location area (step S109).

[0098] Next, the terminal device 20 sets an area determination threshold based on the radio wave intensities of the two reference stations (step S111).

[0099] Next, the terminal device 20 sets the correction value of the correction station for each of one or more correction stations (step S113).

[0100] Then, the terminal device 20 transmits the calibration information including the set information to the server 30, and stores it in the server 30 (step S115).

[0101] The process then ends.

[0102] (Positioning) FIG. 6 is a flowchart showing an example of the flow of processing related to positioning executed by the terminal device 20 according to this embodiment.

[0103] As shown in FIG. 6, first, the terminal device 20 accesses the server 30 and acquires the location information of the beacon 10 (step S201).

[0104] Next, the terminal device 20 accesses the server 30 and acquires the calibration information (step S203).

[0105] Next, the terminal device 20 receives beacon signals from a plurality of beacons 10 in the vicinity and measures the radio wave intensity (step S205).

[0106] Next, the terminal device 20 removes the multipath (step S207). The radio wave strength hereinafter refers to the radio wave strength after the multipath has been removed.

[0107] Next, the terminal device 20 determines the location area based on the radio wave intensity of the surrounding beacons 10 and the area determination threshold included in the calibration information (step S209).

[0108] Next, the terminal device 20 corrects the radio wave intensity of the correction station using the correction value of the correction station included in the calibration information (step S211).

[0109] Then, the terminal device 20 estimates the location information of the terminal device 20 by three-point positioning based on the radio wave strength of the reference station, the corrected radio wave strength of the correction station, and the location information of the reference station and correction station (step S213).

[0110] The process then ends.

[0111] 5. Effects According to the present embodiment described above, the terminal device 20 can remove multipath interference, thereby improving the accuracy of three-point positioning based on the radio wave intensity of effective radio waves.

[0112] Furthermore, according to this embodiment, the terminal device 20 can use the correction value to correct the radio wave intensity of the correction station that has been attenuated by obstacles such as the pillar P or the luggage C. As a result, it is possible to improve the positioning accuracy by improving the fluctuation of the radio waves caused by the influence of the environment such as the pillar P or the luggage C.

[0113] Furthermore, according to this embodiment, the effects of multipath and obstacles can be eliminated, so the beacon 10 can be installed without considering the effects of multipath and obstacles. Therefore, there is no need to install the beacon 10 in a high place such as a ceiling, or to install the beacon 10 while carefully checking the visibility. As a result, it becomes possible to install the beacon 10 by hanging it in an accessible position on a pillar P, thereby reducing installation costs. Furthermore, since work at high places is no longer necessary, it is also possible to reduce maintenance costs during operation, such as battery replacement.

[0114] 6. Hardware Configuration Example Next, the hardware configuration of an information processing device according to this embodiment will be described with reference to Fig. 7. Fig. 7 is a block diagram showing an example of the hardware configuration of an information processing device according to this embodiment. Note that the information processing device 900 shown in Fig. 7 may realize, for example, the terminal device 20 or the server 30 shown in Fig. 1. Information processing by the terminal device 20 or the server 30 according to this embodiment is realized by cooperation between software and hardware described below.

[0115] As shown in FIG. 7 , the information processing device 900 includes a CPU (Central Processing Unit) 901, a ROM (Read Only Memory) 902, a RAM (Random Access Memory) 903, a host bus 904, a bridge 905, an external bus 906, an interface 907, an input device 908, an output device 909, a storage device 910, and a communication device 911.

[0116] The CPU 901 functions as an arithmetic processing device and control device, and controls the overall operation of the information processing device 900 in accordance with various programs. The CPU 901 may also be a microprocessor. The ROM 902 stores programs used by the CPU 901, calculation parameters, etc. The RAM 903 temporarily stores programs used in the execution of the CPU 901, and parameters that change as appropriate during the execution. These are interconnected by a host bus 904 consisting of a CPU bus, etc. The CPU 901 may form, for example, the control unit 24 or the control unit 33.

[0117] The host bus 904 is connected to an external bus 906 such as a PCI (Peripheral Component Interconnect / Interface) bus via a bridge 905. The host bus 904, bridge 905, and external bus 906 do not necessarily need to be configured separately, and these functions may be implemented on a single bus.

[0118] The input device 908 is composed of input means for the user to input information, such as a mouse, keyboard, touch panel, buttons, microphone, switches, and levers, and an input control circuit that generates an input signal based on the user's input and outputs it to the CPU 901. By operating this input device 908, the user operating the information processing device 900 can input various data and instruct processing operations to the information processing device 900. The input device 908 accepts input of the location area at the time of calibration, for example, in the terminal device 20.

[0119] The output device 909 may include, for example, a display device that outputs visual information, such as a liquid crystal display (LCD) device, an OLED (organic light emitting diode) device, or a lamp. The output device 909 may include an audio output device that outputs auditory information, such as a speaker. The output device 909 may include a tactile presentation device that outputs tactile information, such as an eccentric motor. The output device 909 may output the positioning result, for example, on the terminal device 20.

[0120] The storage device 910 is a device for storing data. The storage device 910 may include a storage medium, a recording device for recording data on the storage medium, a reading device for reading data from the storage medium, and a deletion device for deleting data recorded on the storage medium. The storage device 910 is configured, for example, by an HDD (Hard Disk Drive). This storage device 910 drives the hard disk and stores programs executed by the CPU 901 and various data. The storage device 910 may form, for example, the storage unit 23 or the storage unit 32.

[0121] The communication device 911 is, for example, a communication interface configured with a communication device for connecting to a network. The communication device 911 may support either wireless communication or wired communication. The communication device 911 may form, for example, the beacon signal receiving unit 21, the communication unit 22, or the communication unit 31. The communication device 911 may also read information stored in an RFID tag.

[0122] The above describes an example of a hardware configuration capable of realizing the functions of the information processing device 900 according to this embodiment. Each of the above components may be realized using general-purpose components, or may be realized by hardware specialized for the function of each component. Therefore, the hardware configuration used can be changed as appropriate depending on the technical level at the time of implementing this embodiment.

[0123] <7. Supplementary Information> Although the preferred embodiments of the present invention have been described in detail above with reference to the accompanying drawings, the present invention is not limited to such examples. It is clear that a person skilled in the art to which the present invention pertains can conceive of various modified or altered examples within the scope of the technical idea described in the claims, and it is understood that these also naturally fall within the technical scope of the present invention.

[0124] Although not specifically mentioned, the above embodiment is based on the premise that the transmission radio wave strength of beacon signals from all beacons 10 included in the positioning system 1 is the same. Of course, the present invention is also applicable to cases where the transmission radio wave strength of beacon signals from the beacons 10 included in the positioning system 1 varies. In such cases, the terminal device 20 may evaluate the received radio wave strength from the beacon 10 taking into account the transmission radio wave strength of the beacon 10. For example, the terminal device 20 may evaluate that the received radio wave strength of the beacon 10 is stronger the smaller the difference between the transmission radio wave strength and the received radio wave strength. Then, the terminal device 20 may perform various processes such as setting an area determination threshold, selecting a reference station and a correction station, setting a correction value, and positioning based on the received radio wave strength taking into account the transmission radio wave strength.

[0125] In the above embodiment, an example has been described in which the terminal device 20 determines its location area based on an area determination threshold during positioning, but the present invention is not limited to such an example. The terminal device 20 may determine its location area using RFID, as in the case of calibration.

[0126] In the above embodiment, an example in which four beacons 10 are associated with one area has been described, but the present invention is not limited to such an example. Any number of beacons 10, three or more, may be associated with one area. Furthermore, the number of correction stations set in one area is not limited to two, and may be one or three or more.

[0127] In the above embodiment, an example in which the areas are formed in a rectangular shape has been described, but the present invention is not limited to such an example. The areas may have various shapes such as circles, triangles, or hexagons. Furthermore, the areas may overlap each other.

[0128] In the above embodiment, an example in which an area is divided by beacons 10 arranged at the four corners has been described, but the present invention is not limited to such an example. The beacons 10 may be arranged in the center of the area, etc.

[0129] In the above embodiment, an example in which calibration and positioning are performed indoors has been described, but the present invention is not limited to such an example. Calibration and positioning may be performed outdoors.

[0130] The series of processes performed by each device described herein may be implemented using software, hardware, or a combination of software and hardware. The programs constituting the software may be stored in advance, for example, on a recording medium (more specifically, a non-transitory storage medium readable by a computer) provided inside or outside each device. Each program may be loaded into a random access memory (RAM) and executed by a processing circuit such as a central processing unit (CPU) when executed by a computer controlling each device described herein. As an example, a non-transitory storage medium installed in the terminal device 20 may store a program for causing the terminal device 20 to execute the above-described processes, and the terminal device 20 may load and execute the program. As another example, a non-transitory storage medium installed in a server or a portable storage device may store a program for causing the terminal device 20 to execute the above-described processes, and the terminal device 20 may download and execute the program. Examples of the recording medium include a magnetic disk, an optical disk, a magneto-optical disk, and a flash memory. Furthermore, the computer program may be distributed, for example, via a network, without using a recording medium. Furthermore, the above-mentioned computer may be an application-specific integrated circuit such as an ASIC (application specific integrated circuit), a general-purpose processor that executes functions by loading a software program, or a computer on a server used in cloud computing. Furthermore, a series of processes performed by each device described in this specification may be centrally processed by a single computer, or may be distributed and processed by multiple computers. Furthermore, in each of the above-mentioned embodiments, two or more communication means present in one device may be physically realized by a single medium.

[0131] Furthermore, the processes described herein using flowcharts or sequence diagrams do not necessarily have to be performed in the order shown. Some process steps may be performed in parallel. Furthermore, additional process steps may be employed, and some process steps may be omitted.

[0132] REFERENCE SIGNS LIST 1 Positioning system 10 Beacon 11 Beacon signal transmitter 20 Terminal device 21 Beacon signal receiver 22 Communication unit 23 Storage unit 24 Control unit 30 Server 31 Communication unit 32 Storage unit 33 Control unit 9 Network

Claims

1. A positioning system comprising a first terminal device, a second terminal device, and a plurality of beacons, wherein the first terminal device sets two reference stations and one or more correction stations from three or more beacons associated with the area in which the first terminal device is located based on the radio wave strength of a plurality of beacon signals received from the plurality of beacons, sets a correction value for the radio wave strength for each of the one or more correction stations, and generates calibration information including specified information, and the second terminal device refers to the calibration information generated by the first terminal device and measures the position of the second terminal device based on the radio wave strength of the beacon signals received from the two reference stations associated with the area in which the second terminal device is located, and the radio wave strength corrected based on the correction value of the beacon signals received from one or more correction stations.

2. The positioning system of claim 1, wherein the calibration information includes information indicating the area in which the first terminal device is located, information indicating the set reference station and correction station, and information indicating the set correction value.

3. The positioning system of claim 1, wherein the first terminal device sets the two beacons with the strongest radio wave strength among the radio wave strengths of the multiple beacon signals received from the multiple beacons as the reference stations, and sets one or more other beacons as the correction stations.

4. The positioning system of claim 1, wherein the first terminal device sets the difference between the statistical value of the radio wave strength of the beacon signal received from the two reference stations and the radio wave strength of the beacon signal received from the correction station as the correction value of the correction station.

5. The positioning system according to claim 1, wherein the second terminal device calculates the corrected radio wave strength by adding the correction value set in the correction station to the radio wave strength of the beacon signal received from the correction station.

6. The positioning system according to claim 1, wherein the second terminal device measures the position of the second terminal device further based on position information of the reference station and the correction station.

7. The positioning system described in claim 1, wherein the first terminal device sets a first threshold based on a statistical value of the radio wave strength of the beacon signals received from the two reference stations, the calibration information includes the first threshold, and the second terminal device determines the area in which the second terminal device is located based on the first threshold included in the calibration information.

8. The positioning system of claim 7, wherein the second terminal device determines that the second terminal device is located in the area in which the two beacons that are the source of the beacon signal whose radio wave strength is stronger than the first threshold are the two reference stations.

9. The positioning system according to claim 1, wherein the first terminal device accepts input of information indicating the area in which the first terminal device is located.

10. The positioning system of claim 1, wherein the first terminal device and the second terminal device use the radio wave strength of the beacon signal received from the beacon that is stronger than a second threshold as the radio wave strength of the beacon signal received from the beacon.

11. The positioning system described in claim 10, wherein the first terminal device and the second terminal device set the second threshold based on the radio wave strength of one or more beacon signals with the strongest radio wave strength among the radio wave strengths of multiple beacon signals received from the beacon during a predetermined period.

12. The positioning system of claim 1, further comprising a storage device, wherein the first terminal device transmits the generated calibration information to the storage device, and the storage device stores the calibration information received from the first terminal device, and the second terminal device references the calibration information stored in the storage device.

13. The positioning system according to claim 1, wherein the second terminal device stores the calibration information generated by the first terminal device and refers to the stored calibration information.

14. The positioning system according to claim 1, wherein the first terminal device and the second terminal device are the same device.

15. A positioning method comprising: a plurality of beacons transmitting beacon signals; a first terminal device setting two reference stations and one or more correction stations from three or more of the beacons associated with the area in which the first terminal device is located based on the radio wave intensities of the plurality of beacon signals received from the plurality of beacons, and setting a correction value for the radio wave intensity for each of the one or more correction stations; the first terminal device generating calibration information including predetermined information; and a second terminal device referring to the calibration information generated by the first terminal device, and measuring the position of the second terminal device based on the radio wave intensities of the beacon signals received from the two reference stations associated with the area in which the second terminal device is located, and the radio wave intensity corrected based on the correction value of the beacon signals received from one or more correction stations.

16. A terminal device comprising: a beacon signal receiving unit that receives a beacon signal transmitted from a beacon; and a control unit that measures the location of the terminal device based on the beacon signal received by the beacon signal receiving unit, wherein the control unit: based on the radio wave strength of multiple beacon signals received from multiple beacons, sets two reference stations and one or more correction stations from three or more beacons associated with the area in which the terminal device is located, sets a correction value for the radio wave strength for each of the one or more correction stations; generates calibration information including specified information; and refers to the calibration information and measures the location of the terminal device based on the radio wave strength of the beacon signals received from the two reference stations associated with the area in which the terminal device is located, and the radio wave strength corrected based on the correction value of the beacon signals received from one or more correction stations.

17. A non-transitory storage medium storing a program that causes a computer that controls a terminal device having a beacon signal receiving unit that receives beacon signals transmitted from a beacon to function as a control unit that measures the location of the terminal device based on the beacon signals received by the beacon signal receiving unit, wherein the control unit: sets two reference stations and one or more correction stations from three or more beacons associated with the area in which the terminal device is located based on the radio wave strength of multiple beacon signals received from multiple beacons; sets a correction value for the radio wave strength for each of the one or more correction stations; generates calibration information including specified information; and refers to the calibration information and measures the location of the terminal device based on the radio wave strength of the beacon signals received from the two reference stations associated with the area in which the terminal device is located, and the radio wave strength corrected based on the correction value of the beacon signals received from one or more correction stations.

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