Positioning system and positioning method

Abstract

To provide a positioning system and a positioning method for appropriately positioning an object for retaining a receiver.SOLUTION: A positioning system 100 includes: transmission control means 110 for transmitting electric waves from multiple transmitters 10; electric wave information acquisition means 120 for acquiring electric wave information regarding respective electric waves received from the multiple transmitters 10 in a receiver 20; and positioning means 130 for positioning an object T for holding the receiver 20 by calculating the distance between the receiver 20 and the multiple transmitters 10 each on the basis of electric wave strength of the respective electric waves included in the electric wave information. The transmission control means 110 changes electric wave strength such that the receiver 20 can receive electric waves and the waves can be reduced from predetermined strength.SELECTED DRAWING: Figure 5

Description

[Technical field]

[0001] The present invention relates to a positioning system and a positioning method. [Background technology]

[0002] Generally, outdoor positioning techniques using a global navigation satellite system (GNSS) such as a global positioning system (GPS) are known, while indoor positioning techniques using ultra-wide band (UWB), radio frequency identifier (RFID), ultrasonic waves, and geomagnetism are known.

[0003] Furthermore, Patent Document 1 discloses technology relating to a mobile object positioning system that receives signal waves emitted from each of a number of beacons arranged on the ceiling of a building and determines the position of a mobile object based on the direction of arrival of the signal waves. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] International Publication No. 2019 / 031264 Summary of the Invention [Problem to be solved by the invention]

[0005] However, in the mobile positioning system described in Patent Document 1, radio waves transmitted from a transmitter are blocked by obstacles or reflected, causing multipath (delayed waves), and furthermore, radio noise occurs, making radio wave reception at a receiver unstable. As a result, there is a problem that the positioning accuracy of an object holding a receiver is unstable.

[0006] Therefore, an object of the present invention is to provide a positioning system and a positioning method that can appropriately locate an object that holds a receiver. [Means for solving the problem]

[0007] A positioning system according to one embodiment of the present invention is a positioning system that locates an object holding a receiver, and includes a transmission control means for causing a plurality of transmitters to transmit radio waves, a radio wave information acquisition means for acquiring radio wave information relating to each of the radio waves received from the plurality of transmitters at the receiver, and a positioning means for locating the object holding the receiver by calculating the distance between the receiver and each of the plurality of transmitters based on the radio wave strength of each of the radio waves contained in the radio wave information, and the transmission control means changes the radio wave strength so that the receiver can receive the radio waves and so that it becomes weaker than a predetermined strength.

[0008] According to this aspect, the transmission control means causes the multiple transmitters to transmit radio waves, and the radio wave information acquisition means acquires radio wave information relating to each of the radio waves received from the multiple transmitters at the receiver. The positioning means calculates the distance between the receiver and each of the multiple transmitters based on the radio wave strength of each radio wave included in the radio wave information acquired by the radio wave information acquisition means, thereby locating the object holding the receiver. Here, the transmission control means changes the radio wave strength so that the receiver can receive the radio waves and that it becomes weaker than a predetermined strength, thereby narrowing down the positions where the receiver may be located, thereby making it possible to appropriately locate the object.

[0009] In the above aspect, the positioning means may estimate an area in which a receiver may be present for each of the plurality of transmitters based on the radio wave intensity of each radio wave, and may position an object holding a receiver based on the area.

[0010] According to this aspect, the positioning means estimates each area in which a receiver may be present for each of the multiple transmitters, and positions the object holding the receiver based on each of the estimated areas, thereby enabling the object to be appropriately positioned.

[0011] In the above aspect, the transmission control means may change the radio wave strength so that the radio wave can be received by the receiver and becomes weaker from a predetermined strength, and when the radio wave strength of any of the radio waves transmitted from the multiple transmitters becomes the minimum value that can be received by the receiver, the positioning means may locate the object holding the receiver.

[0012] According to this aspect, when the radio wave strength of any of the radio waves emitted from the multiple transmitters reaches the minimum value that can be received by the receiver, the positioning means locates the object holding the receiver, thereby narrowing down the area in which the receiver may be located and enabling more appropriate positioning of the object.

[0013] In the above aspect, the positioning means may use the transmission control means to change the radio wave strength so that the receiver can receive it and the strength becomes smaller than a predetermined strength, detect the minimum value of the radio wave strength of each radio wave transmitted from the multiple transmitters that can be received by the receiver, and position the object holding the receiver using the minimum value of the radio wave strength of each radio wave.

[0014] According to this aspect, the positioning means detects the minimum value of radio wave strength of each radio wave transmitted from a plurality of transmitters that can be received by the receiver, and uses the minimum value of radio wave strength to position the object holding the receiver, thereby further narrowing down the area in which the receiver may be present and enabling more appropriate positioning of the object.

[0015] In the above aspect, the multiple transmitters may be at least two, and may further include a drawing acquisition means for acquiring a drawing including an area in which the object holding the receiver can be positioned, and a position determination means for determining the position of the object positioned by the positioning means based on the drawing.

[0016] According to this aspect, the position determination means determines the position of the object whose position has been determined by the positioning means, based on the drawing, and therefore the position of the object can be appropriately determined.

[0017] In the above aspect, the present invention may further comprise a display means for displaying the position of the object determined by the position determination means using a diagram.

[0018] According to this aspect, the display means displays the position of the target using a drawing, so that the user can properly grasp the position of the target.

[0019] In the above aspect, the device may further include a second transmission control means for causing the multiple transmitters to transmit reference radio waves different from each of the radio waves transmitted from the multiple transmitters, and a reference radio wave detection means for detecting in the receiver that a reference radio wave has been received from any of the multiple transmitters, and when the position determination means detects that the reference radio wave has been received, the device may determine that the object is located at the position of the transmitter that transmitted the reference radio wave.

[0020] According to this aspect, when the reference radio wave detection means detects that the receiver has received the reference radio wave, the position determination means determines that the target is located at the position of the transmitter that transmitted the reference radio wave. This makes it possible to avoid a result in which the target is located in an area on the drawing where the target cannot exist.

[0021] In the above aspect, the device may further include a height information acquisition means for acquiring height information relating to the height position of an object holding the multiple transmitters and receivers, and the positioning means may locate the object holding the receiver based on the height difference between the multiple transmitters and the object holding the receiver.

[0022] According to this aspect, the positioning means locates the position of the object holding the receiver, taking into account the difference in elevation between the transmitter and the receiver, and therefore, the object can be located more appropriately.

[0023] In the above aspect, the plurality of transmitters may be at least three.

[0024] According to this embodiment, if there are at least three transmitters, the target can be appropriately located using the principle of triangulation.

[0025] A positioning method according to one embodiment of the present invention is a positioning method executed by a positioning system that positions an object holding a receiver, and includes a transmission control step of causing multiple transmitters to emit radio waves, a radio wave information acquisition step of acquiring radio wave information regarding each of the radio waves received from the multiple transmitters in the receiver, and a positioning step of locating the object holding the receiver by calculating the distance between the receiver and each of the multiple transmitters based on the radio wave strength of each of the radio waves included in the radio wave information, and in the transmission control step, the radio wave strength is changed so that the receiver can receive the radio waves and is reduced from a predetermined strength.

[0026] According to this aspect, in the transmission control step, radio waves are transmitted from the multiple transmitters, and in the radio wave information acquisition step, the receiver acquires radio wave information relating to each of the radio waves received from the multiple transmitters. In the positioning step, the distance between the receiver and each of the multiple transmitters is calculated based on the radio wave strength of each radio wave included in the radio wave information acquired in the radio wave information acquisition step, thereby locating the object holding the receiver. Here, in the transmission control step, the radio wave strength is changed so that the receiver can receive the radio waves and becomes weaker than a predetermined strength, thereby narrowing down the positions where the receiver may be located, thereby making it possible to appropriately locate the object. Effect of the Invention

[0027] According to the present invention, it is possible to provide a positioning system and a positioning method for appropriately locating the position of an object carrying a receiver. [Brief description of the drawings]

[0028] [Figure 1] 1 is a functional block diagram showing each function of a positioning system 100 according to a first embodiment of the present invention. [Diagram 2] FIG. 1 is a diagram showing an appearance of a target T holding a transmitter 10 and a receiver 20 installed in a positioning system 100 according to a first embodiment of the present invention. [Diagram 3]FIG. 1 is a diagram showing the relationship between received signal strength indicator (RSSI) and distance. [Figure 4] FIG. 13 is a diagram showing how a region in which a receiver 20 may be present is estimated based on the radio wave intensity of each radio wave received by the receiver 20. [Diagram 5] FIG. 1 is a diagram showing how the radio wave intensity transmitted from a transmitter 10 is changed from a predetermined intensity to a smaller intensity, thereby narrowing down the area in which a receiver 20 is located. [Figure 6] FIG. 13 is a diagram showing how an object T is displayed using a drawing. [Figure 7] FIG. 13 is a diagram showing how an object T is positioned at predetermined time intervals and the object T is displayed using a drawing. [Figure 8] 1 is a flowchart showing an outline of a procedure for using the positioning system 100 according to the first embodiment of the present invention. [Figure 9A] 1 is a flowchart showing a process flow of a positioning method M100 executed by the positioning system 100 according to the first embodiment of the present invention. [Figure 9B] 13 is a flowchart showing a process flow of another positioning method M101 executed by the positioning system 100 according to the first embodiment of the present invention. [Figure 10] FIG. 11 is a functional block diagram showing each function in a positioning system 200 according to a second embodiment of the present invention. [Figure 11] FIG. 13 is a diagram showing how four objects are displayed using drawings. [Figure 12] FIG. 11 is a functional block diagram showing each function in a positioning system 300 according to a third embodiment of the present invention. [Figure 13] FIG. 13 is a diagram showing a state in which the difference in height between a transmitter 10 and a receiver 20 is taken into consideration. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0029] Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings. Note that the embodiment described below is merely a specific example for carrying out the present invention, and is not intended to limit the interpretation of the present invention. In addition, in order to facilitate understanding of the description, the same reference numerals are used as far as possible for the same components in each drawing, and duplicated descriptions may be omitted.

[0030] First Embodiment [Positioning system configuration] Fig. 1 is a functional block diagram showing each function of a positioning system 100 according to a first embodiment of the present invention. As shown in Fig. 1, the positioning system 100 includes a transmission control means 110, a radio wave information acquisition means 120, a positioning means 130, a drawing acquisition means 140, a position determination means 150, and a display means 160, and locates a target T holding a receiver 20 while controlling a plurality of transmitters 10A, 10B, ... (hereinafter, sometimes collectively referred to as "transmitters 10").

[0031] The transmission control means 110 controls the multiple transmitters 10A, 10B, ... to transmit radio waves while changing the radio wave intensity. Specifically, the radio wave intensity of the radio waves transmitted from the multiple transmitters 10A, 10B, ... is changed so that the receiver 20 can receive the radio waves and the intensity becomes smaller than a predetermined intensity.

[0032] The radio wave information acquiring means 120 acquires radio wave information relating to each of the radio waves received by the receiver 20 from the multiple transmitters 10A, 10B, . . .

[0033] The positioning means 130 calculates the distance between the receiver 20 and each of the multiple transmitters 10A, 10B, ... based on the radio wave intensity of each radio wave included in the radio wave information acquired by the radio wave information acquisition means 120, thereby locating the target T holding the receiver 20. Detailed processing in the positioning means 130 will be described later.

[0034] Here, in this embodiment, the transmitters 10 may be installed at the four corners of a construction site so as not to interfere with work, for example. In the following, the explanation will be given assuming that four transmitters 10A, 10B, 10C, and 10D are installed.

[0035] Fig. 2 is a diagram showing the transmitter 10 installed in the positioning system 100 according to the first embodiment of the present invention, and the object T holding the receiver 20. As shown in Fig. 2, the transmitters 10A, 10B, 10C, and 10D are installed at the four corners of a construction site, and the object T holding the receiver 20 is located within the construction site. The construction site is typically indoors, and may be, for example, one floor, one section, or one room of an apartment building under construction.

[0036] Transmitters 10A, 10B, 10C, and 10D each transmit a radio wave, which is received by receiver 20. Then, positioning means 130 locates the position of object T holding receiver 20 based on the radio field intensity of each received radio wave.

[0037] Fig. 3 is a diagram showing the relationship between received signal strength indicator (RSSI) and distance. As shown in Fig. 3, the stronger the received signal strength indicator (RSSI), the closer the distance between the receiver and the transmitter, and the weaker the received signal strength indicator (RSSI), the farther the distance between the receiver and the transmitter. In other words, as the distance between the receiver and the transmitter increases, the attenuation rate of the radio wave transmitted from the transmitter increases, and the received signal strength indicator (RSSI) of the radio wave received by the receiver becomes weaker.

[0038] Using this principle, the positioning means 130 locates the position of the object T holding the receiver 20 at the construction site based on the radio waves transmitted from the transmitters 10A, 10B, 10C, and 10D and the radio wave intensity of each radio wave received by the receiver 20.

[0039] Fig. 4 is a diagram showing how a region in which receiver 20 may be located is estimated based on the radio wave intensity of each radio wave received by receiver 20. In Fig. 4, circle 11A centered on transmitter 10A, circle 11B centered on transmitter 10B, circle 11C centered on transmitter 10C, and circle 11D centered on transmitter 10D are depicted.

[0040] 3, the positioning means 130 calculates the distance between the transmitter 10A and the receiver 20 based on the radio wave transmitted from the transmitter 10A and the radio wave intensity of the radio wave received by the receiver 20. That is, the positioning means 130 estimates the distance area from the transmitter 10A in which the receiver 20 is located (circle 11A centered on the transmitter 10A) based on the attenuation rate of the radio wave transmitted from the transmitter 10A.

[0041] Similarly, the positioning means 130 estimates the area of ​​distance from the transmitter 10B to the receiver 20 based on the attenuation rate of the radio wave transmitted from the transmitter 10B (circle 11B centered on the transmitter 10B). The positioning means 130 estimates the area of ​​distance from the transmitter 10C to the receiver 20 based on the attenuation rate of the radio wave transmitted from the transmitter 10C (circle 11C centered on the transmitter 10C). The positioning means 130 estimates the area of ​​distance from the transmitter 10D to the receiver 20 based on the attenuation rate of the radio wave transmitted from the transmitter 10D (circle 11D centered on the transmitter 10D).

[0042] Then, the positioning means 130 estimates the area 21 where the four circles 11A to 11D overlap as an area where the receiver 20 may be present, and positions the object T holding the receiver 20. For example, the positioning means 130 may position the position of the center of gravity of the area 21 as the position of the object T.

[0043] Fig. 5 is a diagram showing how the radio wave intensity of radio waves transmitted from transmitter 10 is changed so as to decrease from a predetermined intensity, thereby narrowing down the area in which receiver 20 is located. As shown in Fig. 5, when the radio wave intensity of radio waves transmitted from transmitters 10A to 10D is changed so as to decrease from a predetermined intensity by transmission control means 110, it can be seen that area 21 where four circles 11A to 11D described using Fig. 4 overlap becomes smaller.

[0044] Specifically, when the radio wave intensity of the radio waves transmitted from transmitters 10A-10D is changed from a predetermined intensity to a smaller intensity by transmission control means 110, area 21 in state (B) shown in FIG. 5 becomes smaller than area 21 in state (A), thereby narrowing down the area in which receiver 20 may be present.

[0045] Furthermore, when the transmission control means 110 is used to further reduce the radio wave intensity of the radio waves transmitted from the transmitters 10A-10D, in state (C) shown in Fig. 5, the radio wave intensity reaches the minimum value that can be received by the receiver 20. As a result, in state (C) shown in Fig. 5, the area 21 where the four circles 11A-11D described using Fig. 4 overlap is minimized, and the area in which the receiver 20 may be present is narrowed down to the smallest possible area.

[0046] If the transmission control means 110 further changes the radio wave intensity of the radio waves transmitted from the transmitters 10A-10D to be smaller, then in state (D) shown in Fig. 5, the area 21 where the four circles 11A-11D described with reference to Fig. 4 overlap no longer exists. That is, although four circles 11A-11D are drawn here, in reality, there are radio waves transmitted from the transmitters 10A-10D that cannot be received by the receiver 20.

[0047] In this way, the radio wave strength of the radio waves transmitted from transmitters 10A to 10D is changed by transmission control means 110 so as to decrease from a predetermined strength, and positioning means 130 narrows down area 21 (area 21 where receiver 20 may be present) where four circles 11A to 11D described using Figure 4 overlap, and positions the area (position) where receiver 20 may be present in the state (C) shown in Figure 5.

[0048] The transmission control means 110 changes the radio wave strength of the radio waves transmitted from the transmitters 10A-10D so as to decrease from a predetermined strength, but may change it stepwise, for example. When the radio wave strength of the radio waves transmitted from the transmitters 10A-10D is decreased stepwise and the receiver 20 is unable to receive any of the radio waves transmitted from the transmitters 10A-10D (corresponding to state (D) shown in FIG. 5), the radio wave strength is restored to the previous step (the radio wave strength is increased by one step). Then, the state where the radio wave strength is restored to the previous step (the state where the radio wave strength is increased by one step) corresponds to state (C) shown in FIG. 5, and the positioning means 130 may position the area (position) where the receiver 20 may be present.

[0049] Returning to the explanation of FIG. 1, the drawing acquisition means 140 acquires a drawing including an area in which the object T holding the receiver 20 can be located. For example, in order to know where a worker is located at a construction site, the drawing acquisition means 140 may acquire design drawings of the construction site. The design drawings may be uploaded to the positioning system 100 by a user, or may be imported into the positioning system 100.

[0050] The position determination means 150 determines the position of the object T whose position has been determined by the positioning means 130, based on the drawing acquired by the drawing acquisition means 140. For example, the positioning means 130 calculates the position of the receiver 20 relative to the four transmitters 10A to 10D, as described with reference to Figs. 4 and 5. Also, the installation positions of the four transmitters 10A to 10D can be identified in the drawing acquired by the drawing acquisition means 140. This allows the position determination means 150 to determine the position of the object T holding the receiver 20 relative to the four transmitters 10A to 10D in the drawing.

[0051] The display means 160 displays the position of the object T determined by the position determination means 150 using the drawing acquired by the drawing acquisition means 140.

[0052] Fig. 6 is a diagram showing how the object T is displayed using a drawing. As shown in Fig. 6, the position of the object T relative to the four transmitters 10A to 10D measured by the positioning means 130 is reflected and displayed on the drawing acquired by the drawing acquisition means 140. For example, when determining where a worker is located at a construction site, the object T is displayed on the design drawing of the construction site, so that the user can confirm the position of the object T from the screen displayed on a monitor or the like.

[0053] Furthermore, at predetermined intervals (e.g., every few seconds, tens of seconds, one minute or several minutes), the positioning means 130 may position the object T that is continuously holding the receiver 20, the position determination means 150 may determine the position of the object T on the drawing, and the display means 160 may display the position of the object T using the drawing.

[0054] 7 is a diagram showing a state in which the position of the object T is measured at predetermined time intervals and the object T is displayed using a drawing. As shown in FIG. 7, by displaying the object T measured at predetermined time intervals on the design drawing of the construction site, the user can check the trajectory of the object T from a screen displayed on a monitor or the like.

[0055] [Procedure for using the positioning system] Next, an overview of a procedure for using the positioning system 100 according to the first embodiment of the present invention will be described.

[0056] Fig. 8 is a flowchart showing an outline of a procedure for using the positioning system 100 according to the first embodiment of the present invention. As shown in Fig. 8, the procedure for using the positioning system 100 includes on-site installation work (steps S11 to S12), system setting (steps S21 to S25), radio wave reception strength confirmation (S31 to S33), and positioning (S41 to S44).

[0057] In step S11, a plurality of transmitters (fixed tags) are installed. As a specific example, four transmitters 10A to 10D are installed at the four corners of a construction site.

[0058] In step S12, a receiver (mobile tag) is set. As a specific example, in order to know where a worker is located at a construction site, a receiver 20 is set to be carried by the worker.

[0059] In step S21, drawings are read in. As a specific example, design drawings of a construction site are read in by uploading them by the user.

[0060] In step S22, the multiple transmitters (fixed tags) installed in step S11 are connected to the receiver (mobile tag) set in step S12. As a specific example, the four transmitters 10A to 10D are connected to the receiver 20 using Bluetooth (registered trademark) or the like.

[0061] In step S23, the positions of the multiple transmitters (fixed tags) installed in step S11 are reflected on the drawing read in step S21. As a specific example, the fact that four transmitters 10A to 10D are installed at the four corners of the construction site is reflected on the design drawing of the construction site.

[0062] In step S24, the position information of the multiple transmitters (fixed tags) reflected on the drawing in step S23 is obtained. As a specific example, the position information of the four transmitters 10A to 10D on the design drawing of the construction site is obtained.

[0063] In step S25, the position information of the multiple transmitters (fixed tags) on the drawing acquired in step S24 is stored in memory. As a specific example, coordinates indicated by an XY coordinate system for the position information of the four transmitters 10A to 10D on the design drawing of the construction site are stored in memory.

[0064] In step S31, radio waves of a predetermined strength are transmitted from the multiple transmitters (fixed tags) installed in step S11. As a specific example, radio waves of a predetermined strength are transmitted from four transmitters 10A to 10D installed at the four corners of a construction site.

[0065] In step S32, the radio waves transmitted from the multiple transmitters (fixed tags) in step S31 are received by a receiver (mobile tag). As a specific example, the receiver 20 receives radio waves from four transmitters 10A to 10D installed at the four corners of a construction site.

[0066] In step S33, it is confirmed whether the radio waves transmitted from the multiple transmitters (fixed tags) in step S31 can be received by the receiver (mobile tag). As a specific example, it is confirmed whether the radio waves from the four transmitters 10A to 10D installed at the four corners of the construction site can be received by the receiver 20 in the entire measurement area. If the radio waves from the four transmitters 10A to 10D can be received by the receiver 20 ("Yes" in step S33), the process proceeds to step S41, and if the receiver 20 cannot receive any of the radio waves from the four transmitters 10A to 10D ("No" in step S33), the process returns to step S31. Then, when the process returns to step S31, the radio wave intensity of the radio waves transmitted from the multiple transmitters (fixed tags) is increased, and the processes of steps S31 to S33 are repeated again.

[0067] In step S41, a subject holding a receiver (mobile tag) enters a room. As a specific example, a subject T (worker) holding a receiver 20 enters a construction site.

[0068] In step S42, radio waves transmitted from multiple transmitters (fixed tags) with varying radio wave intensities are received by a receiver (mobile tag). As a specific example, four transmitters 10A to 10D installed at the four corners of a construction site transmit radio waves with varying intensities from a predetermined intensity to a smaller intensity, and a receiver 20 held by a target T who has entered the construction site receives the radio waves.

[0069] In step S43, the target is located based on the radio wave intensity of the radio waves received by the receiver (mobile tag). As a specific example, as described with reference to Figs. 4 and 5, four circles 11A to 11D are drawn to estimate the distances to the four transmitters 10A to 10D, respectively, based on the radio wave intensity of the radio waves received by the receiver 20. Then, while narrowing down the overlapping area 21, the position of the center of gravity of the area 21 is located as the position of the target T holding the receiver 20.

[0070] In step S44, the target T whose position was measured in step S43 is displayed on the drawing read in step S21. As a specific example, the position information (XY coordinates) of the four transmitters 10A to 10D on the drawing is stored in memory in step S25. The position of the target T on the drawing is displayed based on the position information of the four transmitters 10A to 10D on the drawing and the position information of the target T whose position was measured in step S43 (positional relationship with the four transmitters 10A to 10D). This allows the user to confirm the position of the target T from a screen displayed on a monitor or the like.

[0071] [Positioning method] Next, a specific detailed description will be given of a positioning method for measuring the position of an object, which is executed by the positioning system 100 according to the first embodiment of the present invention.

[0072] 9A is a flowchart showing a process flow of a positioning method M100 executed by the positioning system 100 according to the first embodiment of the present invention. As shown in FIG. 9A, the positioning method M100 includes steps S110 to S180, and each step is executed by a computer included in the positioning system 100.

[0073] In step S110, radio waves are transmitted from a plurality of transmitters (transmission control step). As a specific example, the transmission control means 110 controls the four transmitters 10A to 10D to transmit radio waves.

[0074] In step S120, the radio waves transmitted from the multiple transmitters are received by the receiver. As a specific example, the radio waves transmitted from the four transmitters 10A to 10D are received by the receiver 20, and the radio wave information acquisition means 120 acquires radio wave information related to each radio wave (radio wave information acquisition step).

[0075] In step S130, it is determined whether the receiver 20 can receive each of the radio waves transmitted from the multiple transmitters. As a specific example, it is determined whether the receiver 20 can properly receive each of the radio waves transmitted from the four transmitters 10A to 10D. For example, if all of the radio waves transmitted from the four transmitters 10A to 10D have been received ("Yes" in step S130), the process proceeds to step S140, and if there are any radio waves that have not been received among the radio waves transmitted from the four transmitters 10A to 10D ("No" in step S130), the process proceeds to step S160.

[0076] In step S140, the radio wave intensity of each radio wave received by the receiver is recorded in a memory, etc. As a specific example, receiver 20 receives each radio wave transmitted from four transmitters 10A-10D, and records in a memory, etc., the radio wave intensity included in the radio wave information acquired in step S120 for each received radio wave.

[0077] In step S150, the radio wave intensity of each of the radio waves transmitted from the multiple transmitters is reduced, and the process returns to step S110. As a specific example, the radio wave intensity of the radio waves transmitted from the four transmitters 10A-10D is set to be one step lower. Then, the process returns to step S110, and the transmission control means 110 controls the four transmitters 10A-10D to transmit radio waves at the radio wave intensity set to be one step lower.

[0078] In this manner, the processes of steps S140, S150, and S110 to S130 are repeated until it is determined in step S130 that, among the radio waves transmitted from the four transmitters 10A to 10D, there is any radio wave that has not been received ("No" in step S130).

[0079] Then, if there is any radio wave that has not been received among the radio waves transmitted from the four transmitters 10A to 10D in step S130 ("No" in step S130), the process proceeds to step S160, where the distance is calculated based on the radio wave intensity recorded in step S140 (positioning step). As a specific example, the distance between each of the four transmitters 10A to 10D and the receiver 20 is calculated based on the radio waves transmitted from the four transmitters 10A to 10D and the radio wave intensity of each of the radio waves received by the receiver 20 from the relationship between the received radio wave intensity RSSI and the distance as shown in FIG. 3. Note that the radio wave intensity used in this process (the radio wave intensity recorded in step S140) is the radio wave intensity before the radio wave intensity was reduced in the immediately preceding step S150, and is the radio wave intensity set immediately before (one step before) it was determined in step S130 that there is any radio wave that has not been received.

[0080] In step S170, circles are drawn based on the distances calculated in step S160 (positioning step). As a specific example, based on the distances between each of the four transmitters 10A to 10D and receiver 20 calculated in step S160, four circles 11A to 11D are drawn with the four transmitters 10A to 10D as centers and the distances as radii.

[0081] In step S180, the center of gravity of the area where the circles drawn in step S170 overlap is determined as the position of the target (positioning step). As a specific example, as shown in Fig. 4 and Fig. 5, the center of gravity of area 21 where four circles 11A to 11D drawn around four transmitters 10A to 10D, respectively, overlap is determined as the position of target T holding receiver 20.

[0082] 9A, if any one of the radio waves transmitted from the four transmitters 10A to 10D cannot be received ("No" in step S130), the position of the target T is determined (positioning steps S160 to S180), but this is not limited thereto. For example, the position of the target T may be determined when all of the radio waves transmitted from the four transmitters 10A to 10D cannot be received.

[0083] 9B is a flowchart showing a process flow of another positioning method M101 executed by the positioning system 100 according to the first embodiment of the present invention. As shown in FIG. 9B, the positioning method M101 includes steps S111 to S181, and each step is executed by a computer included in the positioning system 100.

[0084] In step S111, similarly to step S110, radio waves are transmitted from a plurality of transmitters (transmission control step). As a specific example, the transmission control means 110 controls the four transmitters 10A to 10D to transmit radio waves.

[0085] In step S121, similarly to step S120, the radio waves transmitted from the multiple transmitters are received by the receiver. As a specific example, the radio waves transmitted from the four transmitters 10A to 10D are received by the receiver 20, and the radio wave information acquiring means 120 acquires radio wave information related to each radio wave (radio wave information acquiring step).

[0086] In step S131, it is determined whether the receiver 20 can receive each of the radio waves transmitted from the multiple transmitters. As a specific example, it is determined whether the receiver 20 can properly receive each of the radio waves transmitted from the four transmitters 10A to 10D. For example, if at least one of the radio waves transmitted from the four transmitters 10A to 10D has been received ("Yes" in step S131), the process proceeds to step S141, and if not all of the radio waves transmitted from the four transmitters 10A to 10D have been received ("No" in step S131), the process proceeds to step S161.

[0087] In step S141, the radio wave intensity of each radio wave received by the receiver is recorded in a memory, etc. As a specific example, receiver 20 receives at least one of the radio waves transmitted from four transmitters 10A to 10D, and records in a memory, etc., the radio wave intensity included in the radio wave information acquired in step S121 for each received radio wave.

[0088] In step S151 described later, the radio wave intensity of each of the radio waves transmitted from the multiple transmitters is reduced, and as a result, some of the radio waves transmitted from the four transmitters 10A to 10D will no longer be receivable by the receiver 20. The radio waves that can no longer be received were received by the receiver 20 at the radio wave intensity before the radio wave intensity was set to be reduced by one level, and the radio wave intensity that could be received is recorded and stored in a memory or the like.

[0089] On the other hand, even if the radio wave strength of each radio wave transmitted from a plurality of transmitters is reduced in step S151 described later, for radio waves that can be received by receiver 20, the radio wave strength of the previously received radio wave recorded in memory or the like may be updated with the radio wave strength of the radio wave received this time (which is one level lower than the previous time).

[0090] In step S151, similarly to step S150, the radio wave intensity of each of the radio waves transmitted from the multiple transmitters is reduced, and the process returns to step S111. As a specific example, the radio wave intensity of the radio waves transmitted from the four transmitters 10A-10D is set to be reduced by one step. Then, returning to the process of step S111, the transmission control means 110 controls the four transmitters 10A-10D to transmit radio waves at the radio wave intensity set to be reduced by one step. Note that for radio waves that have already become unreceivable by the receiver 20, it is not necessary to set the radio wave intensity to be reduced by one step.

[0091] In this manner, the processes of steps S141, S151, and S111 to S131 are repeated until it is determined in step S131 that not all of the radio waves transmitted from the four transmitters 10A to 10D have been received ("No" in step S131).

[0092] Then, if it is determined in step S131 that all of the radio waves transmitted from the four transmitters 10A-10D have not been received ("No" in step S131), the process proceeds to step S161, where the distance is calculated based on the radio wave intensity recorded in step S141 (positioning step). As a specific example, the distance between each of the four transmitters 10A-10D and the receiver 20 is calculated based on the radio waves transmitted from the four transmitters 10A-10D and the radio wave intensity of each of the radio waves received by the receiver 20, from the relationship between the received radio wave intensity RSSI and the distance as shown in FIG.

[0093] The radio wave strength used in this process (the radio wave strength recorded in step S141) is the minimum value that can be received by the receiver 20 for each of the radio waves transmitted from the four transmitters 10A to 10D. In step S151, the radio wave strength of each of the radio waves transmitted from the four transmitters 10A to 10D is reduced, and while the radio waves can be received by the receiver 20, the received radio waves are recorded (updated) in memory or the like at that radio wave strength. When the radio wave strength is reduced and the receiver 20 cannot receive the radio waves, the radio wave strength recorded in memory or the like is not updated, and the radio wave strength set immediately before (one step before) is stored in the memory or the like. In other words, when the receiver 20 cannot receive all of the radio waves transmitted from the four transmitters 10A to 10D, the minimum value that can be received by the receiver 20 for the radio wave strength of each radio wave is stored in memory or the like.

[0094] In step S171, similarly to step S170, circles are drawn based on the distances calculated in step S161 (positioning step). As a specific example, based on the distances between each of the four transmitters 10A-10D and receiver 20 calculated in step S161, four circles 11A-11D are drawn with the four transmitters 10A-10D as centers and the distances as radii.

[0095] In step S181, similarly to step S180, the position of the center of gravity of the area where the circles drawn in step S171 overlap is determined as the position of the target (positioning step). As a specific example, as shown in Fig. 4 and Fig. 5, the position of the center of gravity of area 21 where four circles 11A to 11D drawn around four transmitters 10A to 10D, respectively, overlap is determined as the position of target T holding receiver 20.

[0096] As described above, according to the positioning system 100 according to the first embodiment of the present invention, the transmission control means 110 causes the four transmitters 10A to 10D to transmit radio waves, and the radio wave information acquisition means 120 acquires radio wave information related to each of the radio waves received from the four transmitters 10A to 10D in the receiver 20. The positioning means 130 calculates the distance between the receiver 20 and the four transmitters 10A to 10D based on the radio wave intensity of each radio wave included in the radio wave information acquired by the radio wave information acquisition means 120, draws circles 11A to 11D centered on each of the four transmitters 10A to 10D, and measures the position of the center of gravity of the overlapping area 21 as the position of the object T holding the receiver 20. The transmission control means 110 changes the radio wave intensity so that the receiver 20 can receive the radio waves and decreases it from a predetermined intensity, thereby reducing the overlapping area 21 of the circles 11A to 11D, and narrowing down the area where the receiver 20 may exist. As a result, the object T can be positioned with high accuracy.

[0097] In this embodiment, the positioning means 130 uses four transmitters 10A to 10D to position the target T holding the receiver 20, but this is not limited thereto. If at least three transmitters 10 are used, the target T holding the receiver 20 can be appropriately positioned using the principle of triangulation. Furthermore, using many (five or more) transmitters 10, for example, the positioning means 130 may use the top three or four radio waves with the strongest radio wave intensity or the lowest radio wave noise among the radio waves received by the receiver 20, and then position the position where the receiver 20 may be located as described above. The number and installation positions of the transmitters 10 may be set according to, for example, the shape of the construction site and the surrounding environment (radio wave environment including a noise environment due to obstacles, etc.).

[0098] Furthermore, in the case of this embodiment where it is necessary to know where a worker is located at a construction site, design drawings of the construction site can be obtained and the design drawings can be used to take into account areas where a worker cannot be present, so that even with two transmitters 10, the object T holding the receiver 20 can be properly positioned.

[0099] In this embodiment, the positioning target (target T) is a worker at a construction site, but the present invention is not limited to this, and a receiver may be held by a person other than the worker and the target may be a positioning target. Also, animals such as pets may be used as the positioning target other than a person, and the user can know the location (behavior) of the animal. Furthermore, objects such as materials and equipment may be used as the positioning target, and the user can know, for example, whether the materials and equipment are stored in a warehouse or where they are being used.

[0100] Hereinafter, the second and third embodiments will be described. In each embodiment, the configurations that differ from the first embodiment of the present invention will be mainly described in detail, and the detailed description of the same configurations as the first embodiment will be omitted or simplified by assigning the same reference symbols.

[0101] <Second embodiment> Fig. 10 is a functional block diagram showing each function of a positioning system 200 according to the second embodiment of the present invention. As shown in Fig. 10, the positioning system 200 includes a transmission control means 110, a radio wave information acquisition means 120, a positioning means 130, a drawing acquisition means 140, a position determination means 150, a display means 160, a second transmission control means 210, and a reference radio wave detection means 220. The positioning system 200 differs from the positioning system 100 according to the first embodiment of the present invention in that it includes the second transmission control means 210 and the reference radio wave detection means 220.

[0102] The second transmission control means 210 controls the plurality of transmitters 10A, 10B, ... to transmit reference radio waves different from the radio waves transmitted from the plurality of transmitters 10A, 10B, .... For example, as described in the first embodiment of the present invention, radio waves (positioning radio waves) are transmitted from the four transmitters 10A to 10D to locate the target T. The radio wave strength of the positioning radio waves is changed so as to become weaker from a predetermined strength, but the radio wave strength of the reference radio waves transmitted here is weaker than the positioning radio waves. For example, the radio wave strength of the reference radio waves is such that they can be received within a range of 1 m to 2 m from the transmitter that transmits the reference radio waves.

[0103] The reference radio wave detection means 220 detects that the receiver 20 has received a reference radio wave from any one of the multiple transmitters 10A, 10B, .... For example, when the object T holding the receiver 20 approaches any one of the four transmitters 10A to 10D (e.g., transmitter 10A), the reference radio wave detection means 220 detects that it has received the reference radio wave transmitted from the transmitter 10A.

[0104] When the position determination means 150 detects that a reference radio wave has been received by the reference radio wave detection means 220, it determines that the object is located at the position of the transmitter that transmitted the reference radio wave. For example, as described above, when the reference radio wave detection means 220 detects that the reference radio wave transmitted from the transmitter 10A has been received by the receiver 20, the position determination means 150 determines that the object T holding the receiver 20 is located at the position of the transmitter 10A.

[0105] More specifically, as described in the first embodiment of the present invention, the positioning means 130 calculates the distance between the receiver 20 and each of the transmitters 10A-10D based on the radio wave intensity of each radio wave transmitted from the transmitters 10A-10D and received by the receiver 20, thereby locating the object T holding the receiver 20. However, here, when the reference radio wave detection means 220 detects that the receiver 20 has received the reference radio wave transmitted from the transmitter 10A, the position determination means 150 determines that the object T is located at the position of the transmitter 10A, not at the position of the located object T. In other words, priority is given to the detection by the reference radio wave detection means 220 that the receiver 20 has received the reference radio wave transmitted from the transmitter 10A.

[0106] Fig. 11 is a diagram showing how four objects are displayed using a drawing. As shown in Fig. 11, the positions of objects T1 to T4 relative to four transmitters 10A to 10D measured by positioning means 130 are reflected and displayed on the drawing, where object T1 receives a reference radio wave transmitted from transmitter 10A, object T2 receives a reference radio wave transmitted from transmitter 10B, and objects T1 and T2 are displayed as objects T1' and T2'.

[0107] For example, at a construction site such as an apartment building, there are areas where workers cannot be present, such as areas where scaffolding has not yet been set up, the outside of the building, areas that cannot be entered, etc. When the positions of the targets T1 to T4 relative to the four transmitters 10A to 10D are measured by the positioning means 130, it is possible that the target T (worker) may be measured in an area where the worker cannot be present due to, for example, the influence of the target worker's movements, radio noise, measurement errors, and individual variations in equipment.

[0108] Here, the positioning means 130 positions the object T1 outside the construction site (outside the apartment building under construction), and the object T2 in an area next to the construction site (an area that cannot be entered). However, since the object T1 receives the reference radio wave transmitted from the transmitter 10A, and the object T2 receives the reference radio wave transmitted from the transmitter 10B, the position determination means 150 prioritizes these and determines that the object T1 and the object T2 are located at the positions of the transmitters 10A and 10B, respectively. Then, on the drawing, they are displayed as the object T1' and the object T2'.

[0109] As described above, according to the positioning system 200 according to the second embodiment of the present invention, even if there is a positioning error, it is possible to avoid a display on the drawing that a worker is located in an area where the worker cannot be present. The user can properly grasp the number of workers staying in a specific area (such as a construction site) without being confused by a display that a worker is located in an area where the worker cannot be present from a screen displayed on a monitor or the like.

[0110] <Third embodiment> Fig. 12 is a functional block diagram showing each function of a positioning system 300 according to the third embodiment of the present invention. As shown in Fig. 12, the positioning system 300 includes a transmission control means 110, a radio wave information acquisition means 120, a positioning means 130, a drawing acquisition means 140, a position determination means 150, a display means 160, and an altitude information acquisition means 310. The positioning system 300 differs from the positioning system 100 according to the first embodiment of the present invention in that it includes the altitude information acquisition means 310.

[0111] The height information acquisition means 310 acquires height information relating to the height position of the target T holding the multiple transmitters 10 and the receiver 20. For example, when the multiple transmitters 10 are installed at a position high from the floor or on the ceiling, the height information acquisition means 310 acquires the height information. When the target T is a worker and the receiver 20 is attached to the worker's chest, the height information acquisition means 310 acquires the height information.

[0112] In addition, a worker may work while climbing up a stepladder or lying on the floor. In this case, the height of the receiver 20 held by the worker changes, so for example, the worker may be made to hold an air pressure sensor, and the height information acquiring means 310 may acquire height information of the worker (target T) holding the receiver 20 based on the air pressure sensor.

[0113] The positioning means 130 locates the position of the object T holding the receiver 20 based on the difference in elevation between the plurality of transmitters 10 and the object T holding the receiver 20 .

[0114] Fig. 13 is a diagram showing a state in which the difference in elevation between the transmitter 10 and the receiver 20 is taken into consideration. As shown in Fig. 13, there is an elevation difference Δh between the transmitter 10 and the receiver 20. The positioning means 130 calculates the distance between the transmitter 10 and the receiver 20 based on the radio wave transmitted from the transmitter 10 and the radio wave intensity of the radio wave received by the receiver 20 from the relationship between the received radio wave strength RSSI and the distance as shown in Fig. 3. The distance calculated here is the radio wave distance L.

[0115] Here, the positioning means 130 calculates the distance L' from the position where the transmitter 10 is installed to the object T holding the receiver 20 based on the elevation difference Δh and the radio wave distance L, and draws a circle with the distance L' as its radius and centered on the transmitter 10, as described using Figures 4 and 5.

[0116] Then, the positioning means 130 measures the position of the center of gravity of an area 21 where the multiple circles drawn in this way (circles 11A to 11D centered on the transmitters 10A to 10D) overlap, as the target position.

[0117] As described above, according to the positioning system 300 according to the third embodiment of the present invention, the positioning means 130 calculates the distance L' from the position where the transmitter 10 is installed to the object T holding the receiver 20, taking into account the difference in elevation between the transmitter 10 and the receiver 20. Then, based on the distance L', the object T is positioned from the area 21 in which the object T may exist, so that the object T can be positioned with higher accuracy.

[0118] The above-described embodiments are intended to facilitate understanding of the present invention, and are not intended to limit the present invention. The elements of each embodiment, as well as their arrangement, materials, conditions, shapes, sizes, etc., are not limited to those shown as examples and can be changed as appropriate. In addition, configurations shown in different embodiments can be partially substituted or combined with each other. [Explanation of symbols]

[0119] 10, 10A to 10D... transmitter, 11A to 11D... circle, 20... receiver, 21... area, 100, 200, 300... positioning system, 110... transmission control means, 120... radio wave information acquisition means, 130... positioning means, 140... drawing acquisition means, 150... position determination means, 160... display means, 210... second transmission control means, 220... reference radio wave detection means, 310... information acquisition means, L... radio wave distance, L'... distance, M100, M101... positioning method, T, T1 to T4, T1', T2'... object

Claims

1. A positioning system for locating a position of an object carrying a receiver, comprising: A transmission control means for causing a plurality of transmitters to transmit radio waves; a radio wave information acquiring means for acquiring radio wave information relating to each of the radio waves received from the plurality of transmitters in the receiver; a positioning means for calculating a distance between the receiver and each of the plurality of transmitters based on the radio wave intensity of each radio wave included in the radio wave information, thereby locating an object holding the receiver; The transmission control means changes the radio wave intensity so that the radio wave can be received by the receiver and becomes weaker than a predetermined strength. Positioning system.

2. the positioning means estimates areas where the receiver may be present for each of the plurality of transmitters based on the radio wave intensity of each of the radio waves, and locates the position of the object holding the receiver based on the areas; The positioning system according to claim 1 .

3. When the transmission control means changes the radio wave intensity so that the radio wave intensity is smaller than a predetermined intensity that the receiver can receive, and the radio wave intensity of any one of the radio waves transmitted from the plurality of transmitters becomes a minimum value that the receiver can receive, The positioning means locates the position of an object holding the receiver. The positioning system according to claim 1 .

4. the positioning means changes the radio wave intensity by the transmission control means so that the radio wave intensity is smaller than a predetermined intensity that the receiver can receive, detects a minimum value of the radio wave intensity of each radio wave transmitted from the plurality of transmitters that can be received by the receiver, and uses the minimum value of the radio wave intensity of each radio wave to position the object holding the receiver. The positioning system according to claim 1 .

5. The plurality of transmitters is at least two, A map acquisition means for acquiring a map including an area in which the object holding the receiver can be located; and a position determination means for determining a position of the object whose position is determined by the positioning means based on the drawing. A positioning system according to any one of claims 1 to 4.

6. The display means further includes a display means for displaying the position of the object determined by the position determination means using the drawing. The positioning system according to claim 5.

7. a second transmission control means for causing the plurality of transmitters to transmit a reference radio wave different from each of the radio waves transmitted from the plurality of transmitters; a reference radio wave detection means for detecting that the receiver has received a reference radio wave from any one of the plurality of transmitters, When the position determination means detects that the reference radio wave has been received, the position determination means determines that the target is located at the position of a transmitter that has transmitted the reference radio wave. The positioning system according to claim 6.

8. The height information acquisition means further includes a height information acquisition means for acquiring height information relating to a height position of an object that holds the plurality of transmitters and the receivers, the positioning means locates the position of the object holding the receiver based on a difference in elevation between the plurality of transmitters and the object holding the receiver; A positioning system according to any one of claims 1 to 4.

9. The plurality of transmitters is at least three. A positioning system according to any one of claims 1 to 4.

10. A positioning method implemented by a positioning system that positions an object carrying a receiver, comprising: a transmission control step of causing a plurality of transmitters to transmit radio waves; a radio wave information acquiring step of acquiring, in the receiver, radio wave information regarding each of the radio waves received from the plurality of transmitters; a positioning step of calculating a distance between the receiver and each of the plurality of transmitters based on the radio wave intensity of each radio wave included in the radio wave information, thereby determining a position of an object holding the receiver; In the transmission control step, the radio wave intensity is changed so that the radio wave intensity can be received by the receiver and is reduced from a predetermined intensity. Positioning method.

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