Position detection system and position detection method

Abstract

Properly detect the location of the device. [Solution] The position detection system 100 includes a memory unit 142 that stores first distances between a first device 104 and each of three or more second devices 105 and the positions of each of the three or more second devices 105, and a position detection unit 143 that determines the position of the first device 104 as the position where a first value for the second distance to three or more spheres corresponding to the three or more second devices 105 is smallest, each of the three or more spheres having a center at the position of the second device 105 corresponding to that sphere and a radius where the first distance between the first device 104 and the second device 105 corresponding to that sphere is the first value, and the first value increases when each of the three or more second distances increases and decreases when each of the three or more second distances decreases.

Description

[Technical Field]

[0001] The present invention relates to a position detection system and a position detection method for detecting the position of a device. [Background technology]

[0002] Patent Document 1 describes estimating the position of a second type radio device by three-point positioning based on the distances between each of a plurality of first type radio devices and the second type radio device. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2024-85741 Summary of the Invention [Problem to be solved by the invention]

[0004] In such a location detection system, it is desirable to be able to appropriately detect the location of the device.

[0005] Therefore, an object of the present invention is to provide a position detection system or a position detection method that can appropriately detect the position of a device. [Means for solving the problem]

[0006] In order to achieve the above-mentioned object, a position detection system according to one embodiment of the present invention comprises: a memory unit that stores first distances between a first device and each of three or more second devices and the positions of each of the three or more second devices; and a position detection unit that determines the position of the first device as the position at which a first value for three or more second distances to three or more spheres corresponding to the three or more second devices is smallest, wherein each of the three or more spheres has the position of the second device corresponding to the sphere as its center, the first distance between the first device and the second device corresponding to the sphere as its radius, and the first value increases when each of the three or more second distances increases and decreases when each of the three or more second distances decreases.

[0007] According to this, the position detection system can appropriately detect the position of the first device even when the accuracy of the distance between the first device and the second device is insufficient. Furthermore, the position detection system can detect the position of the first device with high accuracy by determining the position of the first device as the position where the first value of the second distance from three or more spheres is the smallest.

[0008] For example, the first value may be the sum of the squares of the three or more second distances, or the sum of the absolute values ​​of the cubes of the three or more second distances.

[0009] According to this, the position detection system can detect the position of the first device with high accuracy by determining the position of the first device as the position where the sum of the squares or the absolute value of the cubes of the second distances to three or more spheres is smallest.

[0010] For example, the first value may be a sum of three or more second values ​​corresponding to the three or more second distances, a sum of the squares of the three or more second values, or a sum of the absolute values ​​of the cubes of the three or more second values, and each of the three or more second values ​​may be a value obtained by dividing the second distance of the corresponding second device by the first distance of the corresponding second device.

[0011] According to this, the position detection system can detect the position of the first device with high accuracy by determining the position of the first device as the position where the sum, sum of squares, or sum of absolute values ​​of cubes of three or more second values ​​corresponding to the second distances to three or more spheres is smallest.

[0012] For example, the memory unit may store first distances between the first device and each of four or more second devices including the three or more second devices, and positions of each of the four or more second devices, and the position detection unit may determine, for each group including three or more second devices among the four or more second devices, as a first position, a position where the first values ​​for three or more second distances to three or more spheres corresponding to the three or more second devices included in the group are smallest, each of the three or more spheres having a center at the position of the second device corresponding to the sphere and a radius where the first distance between the first device and the second device corresponding to the sphere is the radius, and the position detection unit may determine the center of gravity of the multiple first positions determined for the multiple groups as the position of the first device.

[0013] According to this, the position detection system can improve the accuracy of detecting the position of the first device by determining the center of gravity of the multiple first positions obtained for the multiple groups as the position of the first device.

[0014] For example, the position detection unit may determine the position where the first value is smallest by performing a third process that repeats a first process of calculating the first value between the three or more balls for each of a target position and a plurality of candidate positions obtained by moving the target position in multiple directions based on a predetermined third distance, and a second process of selecting, from the plurality of candidate positions, a position with the smallest first value as a new target position, until the first value of the target position becomes smallest among the plurality of first values ​​of the target position and the plurality of candidate positions.

[0015] This allows the position detection system to appropriately detect the position where the first value of the second distance to three or more balls is the smallest.

[0016] For example, if, in the third process, the first value of the target position becomes the smallest among the multiple first values ​​of the target position and the multiple candidate positions, the position detection unit may determine the position where the first value is smallest by performing a fourth process in which the third distance is shortened and the third process is performed, and this is repeated until the third distance reaches a lower limit value.

[0017] This allows the position detection system to detect with high accuracy the position where the first value of the second distance to three or more balls is the smallest.

[0018] For example, the position detection unit may determine an initial position of the target position on a line segment connecting the center of a first sphere and the center of a second sphere included in the three or more spheres, and the ratio of the distance between the center of the first sphere and the initial position to the distance between the center of the second sphere and the initial position may be equal to the ratio of the radius of the first sphere and the radius of the second sphere.

[0019] This allows the position detection system to appropriately determine the initial position of the target position, thereby reducing the amount of processing in the third process.

[0020] A position detection system according to one embodiment of the present invention includes a memory unit that stores a first distance between a first device and each of three second devices and the positions of each of the three second devices, and a position detection unit that determines the center of gravity of three intersections corresponding to a set of three consisting of two of three circles corresponding to the three second devices as the position of the first device, wherein each of the three circles has the position of the second device corresponding to that circle as its center and the first distance between the first device and the second device corresponding to that circle as its radius, and the three intersections each correspond to one of the sets of three.

[0021] This allows the position detection system to appropriately detect the position of the first device even when the accuracy of the distance between the first device and the second device is insufficient. Furthermore, the position detection system can detect the position of the first device with high accuracy by determining the center of gravity of the three intersections corresponding to the triplet of two circles as the position of the first device.

[0022] For example, the position detection unit may determine multiple intersections by determining one or two intersections for each of the three sets, select the three intersections from the multiple intersections that have the smallest sum of the distances between the intersections, and determine the center of gravity of the selected three intersections as the position of the first device.

[0023] This allows the position detection system to appropriately select three intersection points when three circles have four or more intersection points, thereby enabling the position detection system to appropriately determine the position of the first device.

[0024] For example, when the first and second circles that constitute the set do not intersect, the position detection unit may determine the midpoint between the first and second points as the intersection point corresponding to the set, where the first point may be the intersection point between the first circle and a line segment connecting the center of the first circle and the center of the second circle, and the second point may be the intersection point between the line segment and the second circle.

[0025] This allows the position detection system to appropriately determine the intersection point even when the two circles constituting a pair do not intersect, thereby enabling the position detection system to appropriately determine the position of the first device.

[0026] For example, when the first circle and the second circle that constitute the set do not intersect, the position detection unit determines an intersection point corresponding to the set on a line segment connecting the first point and the second point, the first point being an intersection point between the first circle and the line segment connecting the center of the first circle and the center of the second circle, the second point being an intersection point between the line segment and the second circle, and the ratio of the distance between the first point and the intersection point to the distance between the second point and the intersection point may be equal to the ratio of the radius of the first circle to the radius of the second circle.

[0027] This allows the position detection system to appropriately determine the intersection point even when the two circles constituting a pair do not intersect, thereby enabling the position detection system to appropriately determine the position of the first device.

[0028] For example, when a first circle constituting the set is contained within a second circle, the position detection unit determines the midpoint between the first point and the second point as the intersection point corresponding to the set, and the first point may be the intersection point between the first circle and a line passing through the center of the first circle and the center of the second circle that is farther from the center of the second circle, and the second point may be the intersection point between the line and the second circle that is closer to the center of the first circle.

[0029] This allows the position detection system to appropriately determine the intersection point even when the first circle constituting the pair is contained within the second circle, thereby enabling the position detection system to appropriately determine the position of the first device.

[0030] For example, when a first circle constituting the set is contained within a second circle, the position detection unit determines an intersection point corresponding to the set on a line segment connecting the first point and the second point, the first point being the intersection point between the first circle and a line passing through the center of the first circle and the center of the second circle and the first circle that is farther from the center of the second circle, the second point being the intersection point between the line and the second circle and the line that is closer to the center of the first circle, and the ratio of the distance between the first point and the intersection point to the distance between the second point and the intersection point may be equal to the ratio of the radius of the first circle to the radius of the second circle.

[0031] This allows the position detection system to appropriately determine the intersection point even when the first circle constituting the pair is contained within the second circle, thereby enabling the position detection system to appropriately determine the position of the first device.

[0032] For example, the memory unit may store a first distance between the first device and each of four or more second devices including the three second devices, and a position of each of the four or more second devices, and the position detection unit may, for each group including three of the four or more second devices, determine the center of gravity of three intersections corresponding to three sets of two of three circles corresponding to the three second devices included in the group as the second position of the first device, each of the three circles having the position of the second device corresponding to the circle as its center and the first distance between the first device and the second device corresponding to the circle as its radius, and the position detection unit may determine the center of gravity of the multiple second positions determined for the multiple groups as the position of the first device.

[0033] According to this, the position detection system can improve the accuracy of detecting the position of the first device by determining the center of gravity of the plurality of second positions obtained for the plurality of groups as the position of the first device.

[0034] Furthermore, a position detection method according to one embodiment of the present invention is a position detection method in a position detection system, which stores first distances between a first device and each of three or more second devices and the positions of each of the three or more second devices, and determines the position of the first device as the smallest first value for three or more second distances to three or more spheres corresponding to the three or more second devices, each of the three or more spheres having the position of the second device corresponding to that sphere as its center and the first distance between the first device and the second device corresponding to that sphere as its radius, and the first value increases when each of the three or more second distances increases and decreases when each of the three or more second distances decreases.

[0035] According to this, the position detection method can appropriately detect the position of the first device even when the accuracy of the distance between the first device and the second device is insufficient. Furthermore, the position detection method can detect the position of the first device with high accuracy by determining the position of the first device as the position where the first value of the second distance from three or more balls is the smallest.

[0036] Furthermore, a position detection method according to one embodiment of the present invention is a position detection method in a position detection system, which stores a first distance between a first device and each of three second devices and the positions of each of the three second devices, and determines the center of gravity of three intersections corresponding to a set of three consisting of two of three circles corresponding to the three second devices to be the position of the first device, each of the three circles having the position of the second device corresponding to that circle as its center and the first distance between the first device and the second device corresponding to that circle as its radius, and each of the three intersections corresponding to the set of three.

[0037] According to this, the position detection method can appropriately detect the position of the first device even when the accuracy of the distance between the first device and the second device is insufficient. Furthermore, the position detection method can detect the position of the first device with high accuracy by determining the center of gravity of the three intersections corresponding to the triplet of two circles as the position of the first device.

[0038] These comprehensive or specific aspects may be realized as a system, a method, an integrated circuit, a computer program, or a computer-readable recording medium such as a CD-ROM, or may be realized as any combination of a system, a method, an integrated circuit, a computer program, and a recording medium. [Effects of the Invention]

[0039] The present invention can provide a position detection system or a position detection method that can appropriately detect the position of a device. [Brief explanation of the drawings]

[0040] [Figure 1] FIG. 1 is a diagram showing a configuration of a position detection system according to an embodiment. [Figure 2] FIG. 2 is a block diagram of a first device according to the embodiment. [Figure 3] FIG. 3 is a block diagram of the second device according to the embodiment. [Figure 4] FIG. 4 is a block diagram of a management device according to an embodiment. [Figure 5] FIG. 5 is a flowchart of a first operation example in the position detection system according to the embodiment. [Figure 6] FIG. 6 is a diagram showing a calculation process of the initial position d0 according to the embodiment. [Figure 7] FIG. 7 is a diagram illustrating an example of a process for determining candidate positions according to the embodiment. [Figure 8] FIG. 8 is a diagram illustrating an example of a process for determining candidate positions according to the embodiment. [Figure 9] FIG. 9 is a diagram illustrating an example of the distance between the candidate position and the sphere according to the embodiment. [Figure 10] FIG. 10 is a flowchart of a second operation example in the position detection system according to the embodiment. [Figure 11] FIG. 11 is a diagram illustrating an example of the intersection determination process according to the embodiment. [Figure 12] FIG. 12 is a diagram illustrating an example of a process for determining an intersection according to the embodiment. [Figure 13] FIG. 13 is a diagram illustrating an example of a process for determining an intersection according to the embodiment. [Figure 14] FIG. 14 is a diagram illustrating an example of a process for determining an intersection according to the embodiment. [Figure 15] FIG. 15 is a diagram showing an example of an intersection point of three circles according to the embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0041] Hereinafter, the embodiments will be specifically described with reference to the drawings.

[0042] It should be noted that the embodiments described below each illustrate a specific example of the present invention. The numerical values, shapes, materials, components, component placement and connection configurations, steps, and step order shown in the following embodiments are merely examples and are not intended to limit the present invention. Furthermore, among the components in the following embodiments, components that are not described in the independent claims that represent the highest concept are described as optional components.

[0043] When estimating the position of a first device (a target of position detection) by triangulation based on the distance between each of a plurality of second devices whose positions are known and a first device whose position is the target of position detection, if the accuracy of the distance between the first device and the second device used for the estimation is insufficient, the position of the first device may not be estimated correctly. In this embodiment, a system that can appropriately perform highly accurate position detection even in such a case will be described.

[0044] [Configuration of location detection system] First, the configuration of a position detection system according to this embodiment will be described. Fig. 1 is a diagram showing the configuration of a position detection system 100 according to this embodiment.

[0045] This position detection system 100 includes a mobile object 101, a management device 103, a first device 104, and a plurality of second devices 105. Note that the number of elements shown in Fig. 1 is an example and is not limited to the number shown in Fig. 1. For example, there may be a plurality of mobile objects 101 and a plurality of first devices 104.

[0046] The position detection system 100 detects the position of a mobile object 101. A first device 104 is carried by or mounted (attached) to the mobile object 101. Each of the plurality of second devices 105 is fixedly installed within a detection area that is the target of position detection. The position of each of the plurality of second devices 105 is recorded in advance in a management device 103.

[0047] 1, the moving body 101 is a person, but may be any moving body. For example, the moving body 101 may be a vehicle or the like. Furthermore, the first device 104 may be mounted (attached) to a piece of luggage or the like being transported.

[0048] The management device 103 is capable of communicating with at least one of the first device 104 and the second device 105, and manages the location of the first device 104 (mobile object 101). For example, the management device 103 is realized by a personal computer, a mobile terminal, or the like. Note that the use described here is an example, and the method of this embodiment can be applied to any system that detects the location of a mobile object. For example, the locations of the multiple second devices 105 only need to be known, and they do not necessarily need to be fixed.

[0049] [Configuration of the first device] 2 is a block diagram showing the configuration of the first device 104. The first device 104 includes a storage unit 121, a control unit 122, a communication unit 123, a distance measurement unit 124, and a power supply unit 125.

[0050] The storage unit 121 stores a first device ID (first device identifier). The first device ID is information for uniquely identifying the first device 104. If the system does not include multiple first devices 104, the first device ID does not need to be used. The control unit 122 controls the communication unit 123, the distance measurement unit 124, etc.

[0051] The communication unit 123 communicates with the management device 103. Specifically, the communication unit 123 transmits the distance measurement result obtained by the distance measurement unit 124 to the management device 103.

[0052] The distance measurement unit 124 measures the distance between the first device 104 and the second device 105. For example, the distance measurement unit 124 performs distance measurement using a UWB (Ultra-Wide Band) wireless system. For example, the distance is measured using the arrival time of a wireless signal (radio wave). Furthermore, the UWB wireless system uses ultrasonic waves (radio waves) in a wide frequency band, which enables highly accurate distance measurement.

[0053] The wireless system used for distance measurement may be other than the UWB wireless system. For example, a wireless system conforming to IEEE802.15.4 or a wireless system using wireless signals in the 920 MHz band, 950 MHz band, or 2.4 GHz band may be used. Alternatively, a wireless system using LPWA (Low Power, Wide Area) wireless signals may be used. Furthermore, two or more of the above wireless systems may be used in combination.

[0054] Furthermore, the distance measurement result transmitted to the management device 103 does not have to be information indicating the distance itself, but may be information that allows the management device 103 to calculate (or estimate) the distance. For example, this information may be the radio wave strength of the radio signal transmitted from the second device 105 received by the first device 104. Alternatively, this information may be the radio wave strength of the radio signal transmitted from the first device 104 received by the second device 105.

[0055] The power supply unit 125 is a power supply that supplies power to the first device 104, and is, for example, a cell or a battery.

[0056] [Configuration of the second device] 3 is a block diagram showing the configuration of the second device 105. The second device 105 includes a storage unit 131, a control unit 132, a communication unit 133, a distance measurement unit 134, and a power supply unit 135.

[0057] The storage unit 131 stores a second device ID (second device identifier). The second device ID is information for uniquely identifying the second device 105. The control unit 132 controls the communication unit 133, the distance measurement unit 134, and the like.

[0058] The communication unit 133 communicates with the management device 103. Note that if the first device 104 transmits the distance measurement result to the management device 103, the second device 105 does not need to include the communication unit 133. Alternatively, instead of the first device 104, each of the multiple second devices 105 may transmit the distance measurement result obtained by the distance measurement unit 134 to the management device 103. In this case, the first device 104 does not need to include the communication unit 123.

[0059] The distance measuring unit 134 measures the distance between the second device 105 and the first device 104. For example, a wireless signal (radio wave) is transmitted and received between the distance measuring unit 124 and the distance measuring unit 134 in response to an instruction from either the distance measuring unit 124 of the first device 104 or the distance measuring unit 134 of the second device 105, thereby measuring the distance between the distance measuring unit 124 (first device 104) and the distance measuring unit 134 (second device 105).

[0060] The power supply unit 135 is a power supply that supplies power to the second device 105, and is, for example, a cell or a battery.

[0061] The first device 104 or the second device 105 may include an operation unit such as a button or a touch panel that accepts user operations.

[0062] [Configuration of management device] Next, a description will be given of the configuration of the management device 103. Fig. 4 is a block diagram showing the configuration of the management device 103. The management device 103 includes a communication unit 141, a storage unit 142, a position detection unit 143, and a display unit 144.

[0063] The communication unit 141 communicates with the first device 104 and the second device 105. The storage unit 142 stores distance measurement results transmitted from the first device 104 or the plurality of second devices 105. The distance measurement results indicate the distance between the first device 104 and each of the plurality of second devices 105. Furthermore, distance measurement between the first device 104 and the plurality of second devices 105 is repeatedly performed at predetermined time intervals, and the distance measurement results are periodically transmitted to the management device 103. Furthermore, the storage unit 142 stores second device position information indicating the positions of the plurality of second devices 105. Note that the second device position information may be input by a user or may be detected in advance using any method. For example, the positions of the plurality of second devices 105 may be detected based on distance measurement results between the plurality of second devices 105.

[0064] The position detection unit 143 uses the distance measurement result to detect (estimate) the position of the first device 104. The display unit 144 displays the position of the first device 104 detected by the position detection unit 143 or information based on the position.

[0065] Note that the position of the first device 104 obtained by the position detection unit 143 does not necessarily need to be displayed on the management device 103. For example, the management device 103 may transmit information indicating the position of the first device 104 to the first device 104, and the first device 104 may display the position of the first device 104 or information based on the position. The management device 103 may also store position detection results at multiple times. The management device 103 may also determine the behavior of the mobile object 101 using the position detection result at a certain time or the position detection results at multiple times. For example, the management device 103 may determine whether the mobile object 101 is performing a predetermined behavior or whether it is performing abnormal behavior.

[0066] The management device 103 may include an operation unit such as a keyboard and mouse, or a touch panel, for accepting user operations.

[0067] The configuration of the position detection system 100 is not limited to the configuration shown in FIG. 1. For example, the functions of the management device 103 may be realized by multiple devices. That is, the management device 103 may include multiple devices, or may include multiple devices (processing units) included in different devices. In other words, the management device 103 may be any one or more devices included in the position detection system 100. For example, some of the functions of the management device 103 may be realized by a PC, and other parts may be realized by a mobile terminal carried by the worker (mobile object 101).

[0068] Furthermore, the mobile terminal carried by the worker may have some or all of the functions of the first device 104. Furthermore, the mobile terminal may have all of the functions of the management device 103. In other words, the management device 103 and the first device 104 may be included in a single device.

[0069] Furthermore, when the management device 103 and the first device 104 are realized as a single device, the transmission of signals between the management device 103 and the first device 104 is performed within the device. In other words, the transmission of the various signals described above is not limited to transmission between devices via a network or the like, but also includes transmission of signals within the device.

[0070] [First operation example] The following describes a first operation example of the position detection system 100. Fig. 5 is a flowchart showing the flow of the first operation example of the position detection system 100. The process shown in Fig. 5 is executed repeatedly at predetermined time intervals, for example.

[0071] First, the management device 103 acquires a distance measurement result of the distance between the first device 104 and each of the multiple second devices 105, transmitted from the first device 104 or the multiple second devices 105 (S101). For example, the first device 104 transmits to the management device 103 a notification signal including a first device ID of the first device 104, a second device ID of each of the multiple second devices 105, and a distance measurement result. Alternatively, each of the multiple second devices 105 transmits to the management device 103 a notification signal including the first device ID of the first device 104, the second device ID of the second device 105, and a distance measurement result of the distance between the first device 104 and the second device 105.

[0072] Next, the management device 103 selects a group of three or more second devices 105 from among the plurality of second devices 105 for which distance measurement results have been obtained (S102), and performs the processes from step S103 onwards on the selected group. Note that instead of targeting all second devices 105 for which distance measurement results have been obtained, it may target second devices 105 of the plurality of second devices 105 for which distance measurement results have been obtained, whose distance to the first device 104 is less than a predetermined threshold.

[0073] In addition, if the number of multiple second devices 105 (or multiple target second devices 105) for which distance measurement results have been obtained is greater than a predetermined upper limit, the management device 103 may select a maximum number of second devices 105 from the multiple second devices 105 for which distance measurement results have been obtained, in order from those with the shortest distance, and select a group including three or more second devices 105 from the selected maximum number of second devices 105.

[0074] Furthermore, the order in which the groups are selected is not particularly limited, but for example, three or more second devices 105 may be selected according to a predetermined order (for example, descending or ascending order of the second device IDs).

[0075] For example, if distance measurement results are obtained for five second devices A, B, C, D, and E as second devices 105, there are five possible group combinations: a group including all five second devices A, B, C, D, and E; five different groups including four second devices out of the five second devices A, B, C, D, and E; and ten different groups including three second devices out of the five second devices A, B, C, D, and E.

[0076] The group-by-group processing may be performed on all of the groups or on some of the groups. For example, the group-by-group processing may be performed on any combination of groups that satisfy a predetermined condition.

[0077] Next, the management device 103 calculates an initial position d0 and sets the initial position d0 as the target position (S103). Fig. 6 is a diagram showing the calculation process of this initial position d0.

[0078] 6, the selected group includes three second devices 105 (hereinafter also referred to as second devices a, b, and c). The second devices a, b, and c are located at positions a0, b0, and c0, respectively. The distance measurement results of the second devices a, b, and c are ra, rb, and rc, respectively. Sphere A is a sphere with a radius ra centered at position a0, sphere B is a sphere with a radius rb centered at position b0, and sphere C is a sphere with a radius rc centered at position c0.

[0079] If the distance measurement accuracy is sufficient, the three spheres A, B, and C intersect at one point, and that point is the position of the first device 104. On the other hand, if the distance measurement accuracy is not sufficient, there is no point where the three spheres A, B, and C intersect.

[0080] First, the management device 103 selects two second devices 105 from the second devices a, b, and c. In this example, the second devices a and b are selected. For example, the management device 103 may select two second devices 105 from the second devices a, b, and c in order of decreasing distance measurement results (ra, rb, rc). Alternatively, the management device 103 may select two second devices 105 according to a predetermined priority order for the multiple second devices 105 (for example, descending or ascending order of the second device ID).

[0081] Next, the management device 103 determines an initial position d0 on the line segment a0-b0. Specifically, the initial position d0 is determined so that the ratio of the distance La between a0 and d0 to the distance Lb between b0 and d0 is equal to the ratio of ra to rb. In other words, the initial position d0 is determined so that La / Lb=ra / rb. Note that, although sphere A and sphere B do not intersect in FIG. 6, the initial position d0 can be determined by a similar method even when sphere A and sphere B intersect.

[0082] The method for determining the initial position d0 is not limited to the above. For example, the initial position d0 may be the midpoint between the positions a0 and b0 of the two selected second devices 105.

[0083] Next, the management device 103 determines a plurality of candidate positions obtained by moving the target position based on the distance D (S104). FIGS. 7 and 8 are diagrams showing an example of this candidate position determination process. In FIG. 7, the distance D is set to a predetermined initial distance D0. As shown in FIG. 7, the management device 103 determines the eight corners of a cube whose center is d0 and whose sides are 2×D0 as eight candidate positions d1 to d8. In other words, the management device 103 determines the eight candidate positions d1 to d8 obtained by moving d0 by the distance D0 in the positive or negative direction on each of the three axes, x, y, and z.

[0084] Note that the candidate positions are not limited to this example. For example, in addition to or instead of the eight candidate positions shown in Fig. 7, the management device 103 may set six candidate positions obtained by moving d0 by a distance D0 in the positive x direction, the negative x direction, the positive y direction, the negative y direction, the positive z direction, or the negative z direction.

[0085] Next, the management device 103 selects the position from the target position and the multiple candidate positions that has the smallest first value S (e.g., the sum of squares of the distances) relating to the distances to each sphere (S105). FIG. 9 is a diagram showing examples of distances Sa, Sb, and Sc between candidate position d1 and spheres A, B, and C, respectively. Here, distance Sa is the distance between intersection a1 and candidate position d1. Intersection a1 is the intersection of a line passing through the center a0 of sphere A and candidate position d1 with sphere A that is closest to candidate position d1. Similarly, distance Sb is the distance between intersection b1 and candidate position d1. Intersection b1 is the intersection of a line passing through the center b0 of sphere B and candidate position d1 with sphere B that is closest to candidate position d1. Distance Sc is the distance between intersection c1 and candidate position d1. Intersection c1 is the intersection of a line passing through the center c0 of sphere C and candidate position d1 with sphere C that is closest to candidate position d1.

[0086] Next, the management device 103 calculates the sum of the squares of the distances Sa, Sb, and Sc as the first value S. That is, S=Sa 2 +Sb 2 +Sc 2 Furthermore, the management device 103 calculates this first value S for each of the target position d0 and candidate positions d1, d2, d3, and d4, and selects the position with the smallest first value S.

[0087] The first value S is a value that increases when each of the distances Sa, Sb, and Sc increases, and decreases when each of the distances Sa, Sb, and Sc decreases. For example, the first value S is not limited to the sum of the squares of the distances, but may be the sum of the distances. That is, S=Sa+Sb+Sc. Alternatively, the first value S may be the sum of the absolute values ​​of the cubes of the distances. That is, S=|Sa 3 |+|Sb 3 |+|Sc 3Alternatively, the first value S may be equal to or greater than the sum of the fourth power of the distances. In other words, the first value S may be the sum of the Nth power of the distances or the sum of the absolute values ​​of the Nth power of the distances (N is a natural number).

[0088] Furthermore, the first value S may be the sum of the Nth power of second values ​​calculated from the respective distances between the candidate position d1 and the multiple spheres, or the sum of the absolute values ​​of the Nth power of the second values ​​(N is a natural number). For example, the second value may be calculated by multiplying the distance between the candidate position d1 and the sphere by a coefficient. For example, the coefficient by which the distance Sa is multiplied may be the reciprocal of the ratio of the distance measurement result ra to the maximum value among the distance measurement results ra, rb, and rc. In other words, the coefficient by which the distance Sa is multiplied may be the value obtained by dividing the maximum value among the distance measurement results ra, rb, and rc by the distance measurement result ra. The coefficient by which the distance Sb is multiplied may be the reciprocal of the ratio of the distance measurement result rb to the maximum value, and the coefficient by which the distance Sc is multiplied may be the reciprocal of the ratio of the distance measurement result rc to the maximum value.

[0089] For example, if ra is the largest of the distance measurement results ra, rb, and rc, and the sum of the second values ​​is used (N=1), the first value S=(ra / ra)×Sa+(ra / rb)×Sb+(ra / rc)×Sc. Note that an arbitrary coefficient or constant k may be used instead of the largest value of the distance measurement results ra, rb, and rc. That is, S=k×(Sa / ra)+k×(Sb / rb)+k×(Sc / rc). Note that k does not have to be used (that is, k=1 may be used). That is, S=(Sa / ra)+(Sb / rb)+(Sc / rc).

[0090] When the sum of the Nth powers of the second value is used, S=(Sa / ra) n +(Sb / rb) n +(Sc / rc) n It is also possible that S=(Sa n / ra)+(Sb n / rb)+(Sc n / rc).

[0091] Also, although an example in which the number of second devices 105 included in the group is three has been described here, the first value S relating to the distance to four or more balls can be calculated in the same way when four or more second devices 105 are included in the group.

[0092] Next, the management device 103 determines whether the target position d0 has been selected (S106). For example, if the candidate position d2 has been selected, the target position d0 has not been selected (No in S106). Therefore, the management device 103 sets the selected candidate position d2 as a new target position (S107) and performs the processes from step S104 onwards again for the new target position d2. This process is repeated until a target position is selected.

[0093] When a target position is selected (Yes in S106), the management device 103 determines whether the current distance D is a predetermined lower limit (S108). In this case, since the distance D0 is not the lower limit (No in S108), the management device 103 sets the distance D to a distance D1 that is shorter than the distance D0 (S109), and repeats the processing from step S104 onwards.

[0094] For example, as shown in FIG. 8, the management device 103 determines the eight corners of a cube whose center is d10 and whose sides are 2×D1 as eight candidate positions d11 to d18.

[0095] Furthermore, this process is repeated until the distance D is set to the lower limit value. If the distance D is the lower limit value (Yes in S108), the management device 103 determines the current target position as the first position of the first device 104 (S110). In this way, through the processes of steps S104 to S110, the management device 103 determines the position where the first value S (e.g., the sum of squares) related to the distances to the three or more spheres corresponding to the three or more second devices 105 is the smallest as the first position of the first device 104. In other words, the management device 103 searches for the position where the first value S (e.g., the sum of squares) related to the distances to the three or more spheres corresponding to the three second devices 105 is the smallest.

[0096] The management device 103 determines whether processing for all groups has been completed (S111). If processing for all groups has not been completed (No in S111), the next group is selected (S102), and the processing from step S103 onwards is performed on the selected group. As a result, the same number of first positions as the number of groups are determined. For example, if four second devices 105 are targeted, there are four possible group combinations, and four first positions are determined. That is, for each group including three or more second devices 105 among the multiple second devices 105, the management device 103 determines as the first position the position at which the first value S (e.g., the sum of squares) related to the distance to three or more spheres corresponding to the three or more second devices 105 included in the group is minimum. In other words, the management device 103 searches for, for each group, the position at which the first value S (e.g., the sum of squares) related to the distance to three or more spheres corresponding to the three or more second devices 105 included in the group is minimum.

[0097] When processing of all groups is completed (Yes in S111), the management device 103 determines the center of gravity (or center) of the multiple first positions of the multiple groups to be the position of the first device 104 (S112).

[0098] 5, the first position is calculated for each of the multiple groups, but the position of only one group may be calculated and the calculated position may be determined as the position of the first device 104. For example, the management device 103 may perform the above process only for a group that includes all of the multiple second devices 105 for which distance measurement results have been obtained. Alternatively, the management device 103 may select a predetermined number of second devices 105, three or more, in order from the second devices 105 with the shortest distances, from the multiple second devices 105 for which distance measurement results have been obtained, and perform the above process only for a group that includes the selected multiple second devices 105.

[0099] Furthermore, in step S105, if there are multiple positions that have the smallest first value S, the management device 103 may select a position based on a predetermined priority order. For example, the priority order may be set for the candidate positions in the order of highest to lowest, from top to bottom to right to left.

[0100] Also, the range in which the first device 104 is present may be determined in advance. In this case, candidate positions are not set outside this range.

[0101] Furthermore, when three second devices 105 exist on a straight line, positions may be determined based on the above range and a priority order (for example, in order from highest to lowest, top right, bottom left), and further based on the above range and a different priority order (for example, in order from highest to lowest, bottom left, top right), and if the two determined positions are different, the one with the smaller first value S may be determined as the first position. Furthermore, if the two determined positions are different and the first values ​​S of the two positions are the same, it may be determined that there is an error. Note that when first positions of multiple groups are calculated, the first position determined to be an error may not be used in calculating the center of gravity. Furthermore, when the first position of only one group is calculated, the user may be notified that an error has occurred.

[0102] Although the above description has been given of an example in which three-dimensional position information is used, two-dimensional position information may also be used, in which case, for example, the spheres in the above description may be replaced with circles.

[0103] [Second example of operation] The following describes a second operation example in the position detection system 100. Note that the management device 103 may have a function to perform both the first and second operation examples, and which one to perform may be set according to a user operation or the like. Alternatively, the management device 103 may have a function to perform only one of the first and second operation examples.

[0104] Fig. 10 is a flowchart showing the flow of the second operation example in the position detection system 100. The process shown in Fig. 10 is executed repeatedly at predetermined time intervals, for example.

[0105] First, the management device 103 acquires the distance measurement results between the first device 104 and each of the plurality of second devices 105, which are transmitted from the first device 104 or the plurality of second devices 105 (S201). Next, the management device 103 selects a group of three second devices 105 from the plurality of second devices 105 for which distance measurement results have been obtained (S202), and performs the processes from step S203 onwards for the selected group.

[0106] The details of the process in step S201 are the same as those in step S101 shown in Fig. 5. The details of the process in step S202 are the same as those in step S101 shown in Fig. 5, except that the number of second devices 105 included in the group is changed from three or more to three.

[0107] Next, the management device 103 selects a set of two second devices 105 from the three second devices 105 in the group (S203). Note that the order in which the sets are selected is not particularly limited, and for example, the two second devices 105 may be selected according to a predetermined order (for example, descending or ascending order of the second device IDs).

[0108] Next, the management device 103 determines the intersection of the circles of the two selected second devices 105 (S204). FIGS. 11 to 14 are diagrams showing an example of the intersection determination process. In FIGS. 11 to 14, the two second devices 105 (hereinafter also referred to as second devices a and b) included in the selected pair are located at positions a0 and b0, respectively. The distance measurement results of the second devices a and b are ra and rb, respectively. Circle A is a circle with a radius of ra centered at position a0, and circle B is a circle with a radius of rb centered at position b0.

[0109] Fig. 11 shows an example where circle A and circle B intersect. In this case, two intersection points E1 and E2 are detected. Fig. 12 shows an example where circle A and circle B touch. In this case, one intersection point E3 is detected.

[0110] FIG. 13 shows an example in which circle A and circle B are separated (do not intersect). In this case, the management device 103 determines the midpoint between points a1 and b1 as intersection E4. Point a1 is the intersection between the line segment connecting a0 and b0 and circle A. Point b1 is the intersection between the line segment connecting a0 and b0 and circle B. Note that the method for determining intersection E4 is not limited to the above. For example, intersection E4 may be the midpoint between a0 and b0.

[0111] 14 shows an example in which circle A is contained within circle B. In this case, the management device 103 determines the midpoint between points a1 and b1 as intersection point E5. Point a1 is the point of intersection between the line passing through a0 and b0 and circle A that is farthest from point b0 (closer to b1). Point b1 is the point of intersection between the line passing through a0 and b0 and circle B that is closer to point a0 (closer to a1).

[0112] In this way, one or two intersections are determined for each pair. Next, the management device 103 determines whether processing of all pairs has been completed (S205). If processing of all pairs has not been completed (No in S205), the next pair is selected (S203), and processing from step S204 onwards is performed on the selected pair. Specifically, there are three pairs of two second devices 105 for three second devices 105. Therefore, by repeating the above processing three times, one or two intersections are determined for each of the three pairs.

[0113] When processing of all pairs has been completed (Yes in S205), the management device 103 selects three intersections from the multiple intersections of the three pairs of pairs that have the smallest total inter-intersection distance (S206). Specifically, the management device 103 selects a total of three combinations by selecting one intersection from each pair. For each combination, the management device 103 calculates the total inter-intersection distance of the three intersections included in that combination. The management device 103 selects the combination with the smallest distance from the calculated distances of the multiple combinations.

[0114] Fig. 15 is a diagram showing an example of the intersection of three circles. In Fig. 15, three second devices 105 (hereinafter also referred to as second devices a, b, and c) included in the selected combination are located at positions a0, b0, and c0, respectively. The distance measurement results of the second devices a, b, and c are ra, rb, and rc, respectively. Circle A is a circle with a radius of ra centered at position a0, circle B is a circle with a radius of rb centered at position b0, and circle C is a circle with a radius of rc centered at position c0.

[0115] In the example shown in FIG. 15, there are two intersections E1 and E2 for the pair of circle A (second device a) and circle B (second device b), there is one intersection E3 for the pair of circle A (second device a) and circle C (second device c), and there are two intersections E4 and E5 for the pair of circle B (second device b) and circle C (second device c). In this case, there are four combinations of three intersections: (E1, E3, E4), (E1, E3, E5), (E2, E3, E4), and (E2, E3, E5), so the sum of the distances between the three intersections is calculated for each of the four combinations. For example, for the combination (E1, E3, E4), the sum of the distance between E1 and E3, the distance between E1 and E4, and the distance between E3 and E4 is calculated.

[0116] Furthermore, in the example shown in FIG. 15, the combination (E2, E3, E5) is selected because the sum of the distances between them is the smallest. Note that the method of selecting the intersections is not limited to this. For example, for a pair of circles with two intersections, one of the two intersections that is closer to the center of the remaining circle of the three circles may be selected. For example, of intersections E1 and E2 between the pair of circles A and B, intersection E2 that is closer to the center c0 of the remaining circle C may be selected. Similarly, of intersections E4 and E5 between the pair of circles B and C, intersection E5 that is closer to the center a0 of the remaining circle A may be selected.

[0117] Next, the management device 103 determines the center of gravity of the selected three intersections as the second position of the first device 104 (S207). That is, the management device 103 determines the center of gravity of the three intersections corresponding to the triplet of two circles out of the three circles corresponding to the three second devices 105 as the second position of the first device 104. For example, in the example shown in Fig. 15, the center of gravity F of the intersections E2, E3, and E5 is determined as the second position.

[0118] Next, the management device 103 determines whether processing for all groups has been completed (S208). If processing for all groups has not been completed (No in S208), the next group is selected (S202), and the processing from step S203 onwards is performed on the selected group. As a result, the same number of second positions as the number of groups are determined. For example, if four second devices 105 are targeted, there are four possible group combinations, and four second positions are determined. In other words, for each group including three second devices 105 out of the multiple second devices 105, the management device 103 determines the second position of the first device 104 as the center of gravity of the three intersections corresponding to three sets of two of the three circles corresponding to the three second devices 105 included in the group.

[0119] When processing of all groups is completed (Yes in S208), the management device 103 determines the center of gravity (or center) of the plurality of second positions of the plurality of groups to be the position of the first device 104 (S209).

[0120] 10, the second position is calculated for each of the multiple groups, but the position of only one group may be calculated and the calculated position may be determined as the position of the first device 104. For example, the management device 103 may select three second devices 105 in order from the shortest distance among the multiple second devices 105 for which distance measurement results have been obtained, and perform the above processing only on the group including the selected three second devices 105.

[0121] 11 to 14 are merely examples, and other methods may be used. For example, when two circles do not intersect as shown in FIGS. 13 and 14, the position of the intersection may be determined using a method similar to the method for determining the initial position d0 shown in FIG. 6. That is, in the example shown in FIG. 13, the ratio of the distance between point a1 and intersection E4 to the distance between point b1 and intersection E4 may be equal to the ratio of ra to rb. In the example shown in FIG. 14, the ratio of the distance between point a1 and intersection E5 to the distance between point b1 and intersection E4 may also be equal to the ratio of ra to rb.

[0122] Furthermore, the method of determining the intersection shown in FIGS. 13 and 14 may be used as the method of determining the initial position d0 shown in FIG.

[0123] Also, the range in which the first device 104 is present may be determined in advance. In this case, in step S206, intersections outside the range may be excluded from the candidates.

[0124] Note that part or all of the processing performed by the management device 103 in the first or second operation example may be performed by the first device 104 or the second device 105.

[0125] [summary] As described above, the position detection system 100 according to this embodiment includes, as described in the first operation example, a memory unit 142 that stores the first distance between the first device 104 and each of the three or more second devices 105 and the positions of each of the three or more second devices 105, and a position detection unit 143 that determines the position of the first device 104 as the position where the first value (e.g., first value S) for three or more second distances (e.g., Sa, Sb, Sc) to three or more spheres (e.g., spheres A, B, C) corresponding to the three or more second devices 105 is smallest. Each of the three or more spheres (e.g., spheres A, B, C) has a center at the position (e.g., a0, b0, c0) of the second device 105 corresponding to the sphere, a first distance (e.g., ra, rb, rc) between the first device 104 and the second device 105 corresponding to the sphere is a radius, and the first value is a value that increases when each of the three or more second distances increases and decreases when each of the three or more second distances decreases.

[0126] This allows the position detection system 100 to appropriately detect the position of the first device 104 even when the accuracy of the distance between the first device 104 and the second device 105 is insufficient. Furthermore, the position detection system 100 can detect the position of the first device 104 with high accuracy by determining the position of the first device 104 as the position where the first value of the second distance to three or more balls is smallest.

[0127] For example, the first value is the sum of the squares of three or more second distances, or the sum of the absolute values ​​of the cubes of three or more second distances.

[0128] According to this, the position detection system 100 can detect the position of the first device 104 with high accuracy by determining the position of the first device 104 as the position where the sum of the squares or the sum of the absolute values ​​of the cubes of the second distances to three or more spheres is smallest.

[0129] For example, the first value is the sum of three or more second values ​​corresponding to three or more second distances, the sum of the squares of three or more second values, or the sum of the absolute values ​​of the cubes of three or more second values, and each of the three or more second values ​​is the second distance of the corresponding second device 105 divided by the first distance of the corresponding second device 105.

[0130] According to this, the position detection system 100 can detect the position of the first device 104 with high accuracy by determining the position of the first device 104 as the position where the sum, sum of squares, or sum of absolute values ​​of cubes of three or more second values ​​corresponding to the second distances to three or more spheres is smallest.

[0131] For example, the storage unit 142 stores first distances between the first device 104 and each of four or more second devices 105 including three or more second devices 105, and the positions of each of the four or more second devices 105. The position detection unit 143 determines, for each group including three or more second devices 105 among the four or more second devices 105, a position where a first value related to the sum of three or more second distances to three or more spheres corresponding to the three or more second devices 105 included in the group is smallest as a first position (for example, S102 to S111 in FIG. 5), and each of the three or more spheres has a center at the position of the second device 105 corresponding to the sphere, and the first distance between the first device 104 and the second device 105 corresponding to the sphere as a radius. The position detection unit 143 determines the center of gravity of the multiple first positions determined for the multiple groups to be the position of the first device 104.

[0132] According to this, the position detection system 100 can improve the accuracy of detecting the position of the first device 104 by determining the center of gravity of the multiple first positions obtained for the multiple groups as the position of the first device 104.

[0133] For example, the position detection unit 143 performs a first process (e.g., S104 to S105 in FIG. 5) to calculate a first value of a second distance between the target position and three or more balls for each of a plurality of candidate positions obtained by moving the target position in a plurality of directions based on a predetermined third distance (e.g., distance D), and a second process (e.g., S106) to select the position with the smallest first value from among the plurality of candidate positions as a new target position. These processes are repeated until the first value of the target position becomes the smallest from among the plurality of first values ​​of the target position and the plurality of candidate positions, thereby determining the position with the smallest first value.

[0134] This allows the position detection system 100 to appropriately detect the position where the first value of the second distance to three or more balls is the smallest.

[0135] For example, in the third process, if the first value of the target position is the smallest among the multiple first values ​​of the target position and multiple candidate positions, the position detection unit 143 performs a fourth process (e.g., S109) in which the third distance is shortened and the third process is performed, and then repeats this process until the third distance reaches a lower limit value, thereby determining the position where the first value is smallest (e.g., S104 to S109).

[0136] This allows the position detection system 100 to detect with high accuracy the position where the first value of the second distance to three or more balls is the smallest.

[0137] For example, as shown in FIG. 6, the position detection unit 143 determines the initial position (e.g., d0) of the target position on a line segment connecting the center (e.g., a0) of a first sphere (e.g., sphere A) included in three or more spheres and the center (e.g., b0) of a second sphere (e.g., sphere B), and the ratio of the distance (e.g., La) between the center of the first sphere and the initial position to the distance (e.g., Lb) between the center of the second sphere and the initial position is equal to the ratio of the radius (e.g., ra) of the first sphere and the radius (e.g., rb) of the second sphere.

[0138] This allows the position detection system 100 to appropriately determine the initial position of the target position, and therefore the position detection system 100 can reduce the amount of processing in the third process.

[0139] As described in the second operation example, the position detection system 100 according to this embodiment includes a storage unit 142 that stores the first distance between the first device 104 and each of the three second devices 105 and the positions of each of the three second devices 105, and a position detection unit 143 that determines the center of gravity (F) of three intersections (e.g., intersections E2, E3, and E5 in FIG. 15 ) corresponding to three pairs of two circles out of three circles (e.g., circles A, B, and C) corresponding to the three second devices 105, as the position of the first device 104. Each of the three circles (e.g., circles A, B, and C) has a center at the position (e.g., a0, b0, and c0) of the second device 105 corresponding to that circle, and a radius is the first distance (e.g., ra, rb, and rc) between the first device 104 and the second device 105 corresponding to that circle. The three intersections (e.g., intersections E2, E3, and E5) each correspond to one of the three pairs of three circles.

[0140] This allows the position detection system 100 to appropriately detect the position of the first device 104 even when the accuracy of the distance between the first device 104 and the second device 105 is insufficient. Furthermore, the position detection system 100 can detect the position of the first device 104 with high accuracy by determining the center of gravity of the three intersections corresponding to the triplet of two circles as the position of the first device 104.

[0141] For example, the position detection unit 143 determines multiple intersections (e.g., intersections E1 to E5 in FIG. 15) by determining one or two intersections for each of the three pairs, selects three intersections (e.g., intersections E2, E3, and E5) from the multiple intersections that have the smallest total distance between them, and determines the center of gravity of the selected three intersections as the position of the first device 104.

[0142] This allows the position detection system 100 to appropriately select three intersection points when three circles have four or more intersection points, thereby enabling the position detection system 100 to appropriately determine the position of the first device 104.

[0143] For example, as shown in FIG. 13, when a first circle (e.g., circle A) and a second circle (e.g., circle B) that form a pair do not intersect, the position detection unit 143 determines the midpoint (e.g., E4) between the first point (e.g., a1) and the second point (e.g., b1) as the intersection point corresponding to the pair, where the first point (e.g., a1) is the intersection point between the line segment connecting the center of the first circle (e.g., a0) and the center of the second circle (e.g., b0) and the first circle (e.g., circle A), and the second point (e.g., b1) is the intersection point between the line segment and the second circle (e.g., circle B).

[0144] This allows the position detection system 100 to appropriately determine the intersection point even when the two circles constituting a pair do not intersect, thereby allowing the position detection system 100 to appropriately determine the position of the first device 104.

[0145] For example, when a first circle (e.g., circle A) and a second circle (e.g., circle B) that constitute a pair do not intersect, the position detection unit 143 determines an intersection point corresponding to the pair on a line segment connecting a first point (e.g., a1) and a second point (e.g., b1), where the first point (e.g., a1) is the intersection point between the line segment connecting the center of the first circle (e.g., a0) and the center of the second circle (e.g., b0) and the first circle (e.g., circle A), and the second point (e.g., b1) is the intersection point between the line segment and the second circle (e.g., circle B), and the ratio of the distance between the first point and the intersection point to the distance between the second point and the intersection point is equal to the ratio of the radius of the first circle (e.g., ra) and the radius of the second circle (e.g., rb).

[0146] This allows the position detection system 100 to appropriately determine the intersection point even when the two circles constituting a pair do not intersect, thereby allowing the position detection system 100 to appropriately determine the position of the first device 104.

[0147] For example, as shown in FIG. 14, when a first circle (e.g., circle A) constituting a pair is contained within a second circle (e.g., circle B), the position detection unit 143 determines the midpoint (e.g., E5) between the first point (e.g., a1) and the second point (e.g., b1) as the intersection point corresponding to the pair, where the first point (e.g., a1) is the intersection point farther from the center of the second circle (e.g., b0) of the first circle (e.g., circle A) of the two intersection points between the line passing through the center of the first circle (e.g., a0) and the center of the second circle (e.g., circle B) and the first circle (e.g., circle A), and the second point (e.g., b1) is the intersection point closer to the center of the first circle (e.g., a0) of the two intersection points between the line and the second circle (e.g., circle B).

[0148] This allows the position detection system 100 to appropriately determine the intersection point even when the first circle constituting the pair is contained within the second circle, thereby allowing the position detection system 100 to appropriately determine the position of the first device 104.

[0149] For example, when a first circle (e.g., circle A) constituting a pair is included in a second circle (e.g., circle B), the position detection unit 143 determines an intersection point corresponding to the pair on a line segment connecting a first point (e.g., a1) and a second point (e.g., b1), where the first point (e.g., a1) is the intersection point farther from the center of the second circle (e.g., b0) of the first circle (e.g., circle A) of two intersection points between the line passing through the center of the first circle (e.g., a0) and the center of the second circle (e.g., b0) and the first circle, and the second point (e.g., b1) is the intersection point closer to the center of the first circle (e.g., a0) of the two intersection points between the line and the second circle (e.g., circle B), and the ratio of the distance between the first point and the intersection point to the distance between the second point and the intersection point is equal to the ratio of the radius of the first circle (e.g., ra) to the radius of the second circle (e.g., rb).

[0150] This allows the position detection system 100 to appropriately determine the intersection point even when the first circle constituting the pair is contained within the second circle, thereby allowing the position detection system 100 to appropriately determine the position of the first device 104.

[0151] For example, the storage unit 142 stores first distances between the first device 104 and each of four or more second devices 105, including three second devices 105, and the positions of each of the four or more second devices 105. For each group including three of the four or more second devices 105, the position detection unit 143 determines, as the second position of the first device 104, the center of gravity of three intersections corresponding to three sets of two of the three circles corresponding to the three second devices 105 included in the group (for example, S202 to S208 in FIG. 10 ), and each of the three circles has the position of the second device 105 corresponding to the circle as its center, and the first distance between the first device 104 and the second device 105 corresponding to the circle as its radius. The position detection unit 143 determines, as the center of gravity of the multiple second positions determined for the multiple groups, the position of the first device 104 (for example, S209).

[0152] According to this, the position detection system 100 can improve the accuracy of detecting the position of the first device 104 by determining the center of gravity of the plurality of second positions obtained for the plurality of groups as the position of the first device 104.

[0153] Although the position detection system according to the embodiment of the present invention has been described above, the present invention is not limited to this embodiment.

[0154] For example, each processing unit included in each device included in the position detection system according to the above embodiment is typically realized as an LSI, which is an integrated circuit. These may be individually implemented as single chips, or some or all of them may be integrated into a single chip.

[0155] Furthermore, the integration is not limited to LSI, but may be realized by dedicated circuits or general-purpose processors. FPGAs (Field Programmable Gate Arrays), which can be programmed after LSI fabrication, or reconfigurable processors, which allow the connections and settings of circuit cells within LSIs to be reconfigured, may also be used.

[0156] Furthermore, some or all of the functions of the devices included in the position detection system according to the above-described embodiments may be realized by a processor such as a CPU executing a program.

[0157] Furthermore, the present invention may be the above-mentioned program, or a non-transitory computer-readable recording medium on which the above-mentioned program is recorded. Needless to say, the above-mentioned program can be distributed via a transmission medium such as the Internet.

[0158] Furthermore, the present invention can be realized not only as a position detection system, but also as a first device, a second device, or a management device included in the position detection system. Furthermore, the present invention can also be realized as a position detection method having characteristic means included in such a position detection system as steps, or as a program that causes a computer to execute such characteristic steps.

[0159] Furthermore, all the numbers used above are merely examples for the purpose of specifically explaining the present invention, and the present invention is not limited to the numbers used as examples.

[0160] The division of functional blocks in the block diagram is an example, and multiple functional blocks may be realized as a single functional block, one functional block may be divided into multiple blocks, or some functions may be moved to another functional block.Furthermore, the functions of multiple functional blocks having similar functions may be processed in parallel or in time-sharing by a single piece of hardware or software.

[0161] The order in which the steps are performed shown in the above flowchart is merely an example for specifically explaining the present invention, and other orders may be used. Also, some of the steps may be performed simultaneously (in parallel) with other steps.

[0162] Although the position detection system according to one or more aspects has been described based on the embodiments, the present invention is not limited to these embodiments. As long as it does not deviate from the spirit of the present invention, various modifications conceivable by those skilled in the art to the present embodiments and configurations constructed by combining components of different embodiments may also be included within the scope of one or more aspects. [Industrial Applicability]

[0163] The present invention can be applied to a position detection system and the like. [Explanation of symbols]

[0164] 100 Position Detection System 101 Mobile 103 Management device 104 1st device 105 2nd device 121, 131, 142 Storage section 122, 132 control section 123, 133, 141 Communications Department 124, 134 Distance measurement section 125, 135 Power supply section 143 Position detection unit 144 Display section

Claims

1. a storage unit that stores a first distance between a first device and each of three or more second devices and a position of each of the three or more second devices; a position detection unit that determines, as the position of the first device, a predetermined position at which a first value relating to three or more second distances between three or more spheres corresponding to the three or more second devices and the predetermined position is smallest; Each of the three or more spheres has a center at the position of the second device corresponding to the sphere, and a radius of the center is the first distance between the first device and the second device corresponding to the sphere; The first value is a value that increases when each of the three or more second distances increases, and decreases when each of the three or more second distances decreases. Position sensing system.

2. The first value is the sum of squares of the three or more second distances or the sum of absolute values ​​of cubes of the three or more second distances. The position sensing system of claim 1 .

3. the first value is a sum of three or more second values ​​corresponding to the three or more second distances, a sum of squares of the three or more second values, or a sum of absolute values ​​of cubes of the three or more second values; Each of the three or more second values ​​is a value obtained by dividing the second distance of the corresponding second device by the first distance of the corresponding second device. The position sensing system of claim 1 .

4. the storage unit stores first distances between the first device and each of four or more second devices including the three or more second devices, and positions of each of the four or more second devices; The position detection unit For each group including three or more second devices among the four or more second devices, determining, as the first position, the predetermined position at which the first values ​​for three or more second distances between the predetermined position and three or more spheres corresponding to three or more second devices included in the group are smallest; Each of the three or more spheres has a center at the position of the second device corresponding to the sphere, and a radius of the center is the first distance between the first device and the second device corresponding to the sphere; The position detection unit determining a center of gravity of the first positions determined for the groups at the position of the first device; The position sensing system of claim 1 .

5. The position detection unit a first process of calculating the first value of the three or more spheres for each of a target position and a plurality of candidate positions obtained by moving the target position in a plurality of directions based on a predetermined third distance; a second process of selecting, from the plurality of candidate positions, a position having the smallest first value as a new target position; A third process is performed repeatedly until the first value of the target position becomes the smallest among the plurality of first values ​​of the target position and the plurality of candidate positions, thereby determining the predetermined position at which the first value becomes the smallest. The position sensing system of claim 1 .

6. The position detection unit In the third process, if the first value of the target position is smallest among the plurality of first values ​​of the target position and the plurality of candidate positions, a fourth process is performed in which the third distance is shortened and the third process is performed, and this fourth process is repeated until the third distance reaches a lower limit value, thereby determining the predetermined position at which the first value is smallest.

6. The position detection system of claim 5.

7. The position detection unit determining an initial position of the target position on a line segment connecting a center of a first sphere and a center of a second sphere included in the three or more spheres; The ratio of the distance between the center of the first sphere and the initial position to the distance between the center of the second sphere and the initial position is equal to the ratio of the radius of the first sphere to the radius of the second sphere.

6. The position detection system of claim 5.

8. A position detection method in a position detection system, comprising: storing a first distance between the first device and each of three or more second devices and a position of each of the three or more second devices; determining, as the position of the first device, a predetermined position at which first values ​​relating to three or more second distances between three or more spheres corresponding to the three or more second devices and a predetermined position are smallest; Each of the three or more spheres has a center at the position of the second device corresponding to the sphere, and a radius of the center is the first distance between the first device and the second device corresponding to the sphere; The first value is a value that increases when each of the three or more second distances increases, and decreases when each of the three or more second distances decreases. Position sensing method.

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