Location tracking device, location tracking method, and measuring trolley

Abstract

To improve position specification precision of a worker.SOLUTION: A position specification device (1) includes: an acquisition part (10) which acquires a plurality of magnetic intensities measured in a movement path of a worker (W) in a positioning object region and a movement distance of the worker (W); an estimation part (20) which estimates the path where the worker (W) moves by collating a change pattern of the plurality of magnetic intensities accompanying the movement of the worker (W) that the acquisition part (10) acquires with a change pattern of magnetism in a collation object path which has a length corresponding to the movement distance in the collation object path specified by connecting at least some successive measurement points among a plurality of measurement points where magnetism is previously measured in the positioning object region; and a specification part (30) which specifies the location of the worker (W) based upon the path that the estimation part (20) has estimated.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a positioning device that identifies the position of an object to be positioned within a positioning target area. [Background technology]

[0002] When workers are inspecting equipment on-site, there is a need for a system that can pinpoint the location of the worker (the object being measured) in real time in order to quickly detect any unforeseen accidents.

[0003] Global Navigation Satellite Systems (GNSS), such as GPS (Global Positioning System), are known technologies for determining the location of objects to be positioned, such as people. However, these systems are difficult to use for indoor location determination because radio waves do not penetrate well indoors. In addition, methods using radio waves such as Wi-Fi® and Bluetooth® are known for determining the location of objects to be positioned indoors. However, these technologies require the installation of radio wave transmitting equipment, such as Wi-Fi® base stations and Bluetooth® beacons, inside or around the structure. Furthermore, depending on the size and structure of the structure being located, radio wave reception may be difficult, and the accuracy of location determination may decrease. Therefore, there is a need for a location determination method that can be used indoors and does not require the installation of radio wave transmitting equipment.

[0004] As an example of such location estimation technology, Patent Document 1 discloses a system that identifies a person's (user's) location by comparing a pre-generated magnetic map with magnetic data collected by a mobile terminal. [Prior art documents] [Patent Documents]

[0005] [Patent Document 1] Japanese Patent Publication No. 2013-210866 [Overview of the project] [Problems that the invention aims to solve]

[0006] However, conventional methods, when comparing a pre-generated magnetic map with magnetic data collected by a mobile device, match each point on the magnetic map with a single magnetic data point collected by the mobile device. Therefore, if there are multiple points on the magnetic map with magnetic fields of the same magnitude as a single magnetic field collected by the mobile device, it becomes impossible to accurately pinpoint the location of a person (user).

[0007] One aspect of the present invention aims to realize a positioning device and a positioning method that can improve the accuracy of determining the position of an object to be positioned. [Means for solving the problem]

[0008] To solve the above problems, a positioning device according to one aspect of the present invention is a positioning device that identifies the position of an object to be positioned in a positioning target area, and includes: an acquisition unit that acquires a plurality of magnetic fields measured along the movement path of the object to be positioned in the positioning target area and the distance traveled by the object to be positioned along the movement path; an estimation unit that estimates the path traveled by the object to be positioned by comparing (1) the change pattern of the plurality of magnetic fields acquired by the acquisition unit with the movement of the object to be positioned, and (2) a path identified by connecting at least some of the consecutive measurement points among a plurality of measurement points where magnetic fields have been measured in advance in the positioning target area, with the change pattern of the magnetic fields of the matching target path having a length corresponding to the distance traveled; and a identification unit that identifies the position of the object to be positioned based on the path traveled by the object to be positioned estimated by the estimation unit.

[0009] In order to solve the above problems, a position identification method according to an aspect of the present invention is a position identification method for identifying the position of a positioning target in a positioning target area, including: a first magnetic component measurement step of pre-measuring the magnetism of a plurality of measurement points in the positioning target area; a second magnetic component measurement step of measuring a plurality of magnetisms in the movement path of the positioning target in the positioning target area; an estimation step of estimating the path along which the positioning target has moved by comparing (1) the change pattern of the plurality of magnetisms measured in the second magnetic component measurement step due to the movement of the positioning target, and (2) the magnetic change pattern of the comparison target path, which is a path specified by connecting at least some of the continuous measurement points among the plurality of measurement points measured in the first magnetic component measurement step, and the length of the comparison target path corresponding to the movement distance of the positioning target in the second magnetic component measurement step; and a specification step of specifying the position of the positioning target based on the path along which the positioning target has moved estimated in the estimation step.

Advantages of the Invention

[0010] According to an aspect of the present invention, the accuracy of identifying the position of the positioning target can be improved.

Brief Description of the Drawings

[0011] [Figure 1] It is a block diagram showing the main configuration of a position identification device according to an embodiment of the present invention. [Figure 2] It is a schematic diagram showing an example of the floor of the positioning target area. [Figure 3] It is a side view of a measuring trolley according to an embodiment of the present invention. [Figure 4] It is a flowchart showing an example of the position identification process according to an embodiment of the present invention. [Figure 5] It is a flowchart showing an example of the process in the first information generation step. [Figure 6] It is a flowchart showing an example of the process in the positioning step.

Embodiments for Carrying Out the Invention

[0012] The following describes in detail one embodiment of the present invention. Figure 1 is a block diagram showing the main components of the location identification device 1 in this embodiment. The location identification device 1 in this embodiment is a device for determining the location of a worker W, which is the target of positioning, in a positioning target area such as inside a building where radio waves used for GPS or the like are difficult to reach, that is, for determining the location of the worker W.

[0013] Prior to describing the location identification device 1, the information necessary for identifying the location of worker W by the location identification device 1, as well as the device and method for acquiring such information, will be described. At least the following first and second pieces of information are required for the location identification device 1 to identify the location of worker W.

[0014] (1st information) The first piece of information includes magnetic and atmospheric pressure measurements taken in advance at multiple measurement points within the positioning area, as well as information on the location of each measurement point. Figure 2 is a schematic diagram showing an example of the floor F within the positioning area. Magnetic and atmospheric pressure measurements are taken at multiple measurement points P along the paths that worker W may travel within the positioning area, as shown in Figure 2. Here, "multiple measurement points P along the paths that worker W may travel" does not mean measurement points P along a single straight path, but rather multiple measurement points P along all possible paths that worker W may travel.

[0015] The first information, including the measured magnetic and atmospheric pressure, as well as the position of the measurement point P where the magnetic and atmospheric pressure were measured, is stored in the memory unit 40 of the positioning device 1, which will be described later. The first information includes the magnitudes of the horizontal and vertical components of the magnetic field as magnetic information. The horizontal and vertical components of the magnetic field included in the first information are the horizontal and vertical components in the global coordinate system. The "global coordinate system" is a coordinate system in which the plane parallel to the Earth's surface is the XY plane consisting of the X and Y axes, and the vertical direction is the Z axis. Furthermore, it is not necessary to measure atmospheric pressure at each measurement point P; it may be measured only once for each floor of the positioning target area.

[0016] The distances between the above-mentioned multiple measurement points are preferably at regular intervals. This allows for a more accurate calculation of the similarity, as described later. The first information may be obtained, for example, by having a measurer equipped with a magnetic measuring device measure the magnetism every time they travel a certain distance. Alternatively, the first information may be obtained using the measuring cart 100 described below.

[0017] Figure 3 is a side view of the measuring trolley 100. As shown in Figure 3, the measuring trolley 100 includes a mounting section 110, wheels 120, a first measuring section 130 (first recording section), and a second measuring section 140 (second recording section).

[0018] The mounting section 110 is a platform on which the first measuring section 130 and the second measuring section 140, which will be described later, are mounted. The upper surface 111 of the mounting section 110 is a plane parallel to the horizontal plane.

[0019] The wheels 120 are located below the mounting section 110, with two wheels each at the front and rear in the direction of travel of the measuring trolley 100 (leftward in Figure 3). In Figure 3, only two of the four wheels 120 are shown.

[0020] On the inside of the wheel 120, specifically the front left wheel 120 in the direction of travel of the measuring trolley 100 (hereinafter referred to as wheel 120A to distinguish it from the other wheels), four north-pole magnets 121 and four south-pole magnets 122 are arranged alternately at equal intervals along the circumference of wheel 120A. Note that the number of north-pole magnets 121 and south-pole magnets 122 arranged on wheel 120A is not limited to four of each, and other numbers may be used.

[0021] A Hall sensor 123 is provided on the inside of the wheel 120A. The Hall sensor 123 detects the north pole magnet 121 and the south pole magnet 122 when they approach the Hall sensor 123 by a predetermined distance or more. When the Hall sensor 123 detects the north pole magnet 121, it outputs "1" to the second measuring unit 140, which will be described later, and when it detects the south pole magnet 122, it outputs "0" to the second measuring unit 140, which will be described later.

[0022] The first measuring unit 130 measures magnetism and atmospheric pressure. The first measuring unit 130 may be a mobile device such as a smartphone or tablet. The first measuring unit 130 measures magnetism and atmospheric pressure at predetermined time intervals and records the measured magnetism and atmospheric pressure, as well as the time at which the magnetism and atmospheric pressure were measured. The first measuring unit 130 outputs the measured magnetism and atmospheric pressure, as well as the time at which the magnetism and atmospheric pressure were measured, to the second measuring unit 140. The first measuring unit 130 also uses an acceleration sensor (not shown) provided in the first measuring unit 130 to acquire the tilt angle of the first measuring unit 130 with respect to the horizontal direction (i.e., the angle between the first measuring unit 130 and the ground surface). Note that the sensor used to acquire the tilt angle of the first measuring unit 130 with respect to the horizontal direction is not limited to an acceleration sensor, and other sensors may be used.

[0023] The first measuring unit 130 calculates the horizontal and vertical components of the measured magnetic field in a global coordinate system using the angle between the first measuring unit 130 and the ground surface, and outputs them to the second measuring unit 140. If the angle between the first measuring unit 130 and the ground surface is 0°, the first measuring unit 130 may output to the second measuring unit 140 either the horizontal and vertical components in the global coordinate system, or the horizontal and vertical components in the coordinate system using the angle acquired by the acceleration sensor of the first measuring unit 130.

[0024] The second measuring unit 140 is composed of a computing device (e.g., a laptop PC). It calculates the distance traveled by the measuring cart 100 from the output of the Hall sensor 123. Here, since the circumference of the wheel 120A is known, the distance traveled by the measuring cart 100 from one switch of the Hall sensor 123 to the next switch is 1 / 8 of the circumference of the wheel 120A. Note that the distance traveled by the measuring cart 100 from one switch of the Hall sensor 123 to the next switch varies depending on the number of N-pole magnets 121 and S-pole magnets 122 placed on the wheel 120A. The second measuring unit 140 calculates the distance traveled by the measuring cart 100 based on the number of times the output of "0" and "1" from the Hall sensor 123 switches (i.e., the amount of rotation of the wheel 120A), and records the calculated distance traveled. Furthermore, the second measuring unit 140 records the time the measuring trolley 100 traveled in a storage unit (not shown).

[0025] Furthermore, the second measurement unit 140 acquires the position where the measurement trolley 100 started moving, either by visual inspection or using a commercially available indoor positioning system (for example, SLAM (Simultaneous Localization and Mapping)), and records the acquired position of the measurement trolley 100 and the time at which that position was acquired in the storage unit.

[0026] Furthermore, the second measurement unit 140 records the magnetic field and atmospheric pressure output from the first measurement unit 130, as well as the time at which the magnetic field and atmospheric pressure were measured, in the storage unit. The magnetic field and the position of the measurement point P recorded by the second measurement unit 140 may be used as a magnetic map in the first information generation process (step S1) and the positioning process (step S2), which will be described later.

[0027] The second measuring unit 140 links the distance traveled by the measuring trolley 100, the position where the measuring trolley 100 started moving, and the magnetic and atmospheric pressure measurements stored in the storage unit with the time, thereby generating first information including the magnetic and atmospheric pressure measurements, and the position of the measurement point P where the magnetic and atmospheric pressure measurements were taken, and outputs this information to the position identification device 1, which will be described later. The first information output from the second measuring unit 140 is stored in the storage unit 40, which will be described later.

[0028] By using the above-described measuring cart 100, the measuring person can move the measuring cart 100 along a path where the worker W may move within the positioning target area, thereby automatically and accurately measuring the magnetic field and atmospheric pressure, as well as the position of the measurement point P where the magnetic field and atmospheric pressure were measured.

[0029] In this embodiment, the measuring trolley 100 had a north pole magnet 121 and a south pole magnet 122 positioned on the front and left-side wheel 120A of the wheels 120 in the direction of travel of the measuring trolley 100, but it is not limited to this. In one embodiment of the present invention, the measuring trolley 100 may be calculated by positioning the north pole magnet 121 and the south pole magnet 122 on the wheels 120 other than wheel 120A.

[0030] In this embodiment, the measuring trolley 100 was configured to measure magnetism and atmospheric pressure with a first measuring unit 130 and measure the distance traveled by the measuring trolley 100 with a second measuring unit 140. However, the measuring trolley 100 of the present invention is not limited to this configuration. The measuring trolley 100 of the present invention may measure magnetism, atmospheric pressure, and the distance traveled by the measuring trolley 100 with a single measuring unit.

[0031] (Second information) The second information includes magnetic and atmospheric pressure measurements taken at multiple locations while worker W moves within the positioning target area, as well as information on the distance traveled by worker W. The second information is automatically measured at predetermined time intervals by a sensor 200 (e.g., a smartphone or tablet) carried by worker W that is capable of measuring magnetic field, atmospheric pressure, and distance traveled. The second information, including the information measured by the sensor 200, is transmitted to the positioning device 1.

[0032] The second piece of information includes the magnitudes of the horizontal and vertical components of the magnetic field as magnetic information. The horizontal and vertical components of the magnetic field are the horizontal and vertical components in a global coordinate system calculated based on the tilt angle of the sensor 200 relative to the horizontal direction, obtained using the acceleration sensor (not shown) and gyro sensor (not shown) provided by the sensor 200.

[0033] (Location device 1) Next, the details of the location identification device 1 in this embodiment will be described. As shown in Figure 1, the location identification device 1 comprises an acquisition unit 10, an estimation unit 20, a identification unit 30, and a storage unit 40.

[0034] The acquisition unit 10 acquires second information from the sensor 200 via wireless communication, which includes magnetic and atmospheric pressure measurements taken at multiple locations while the worker W moves within the positioning target area, as well as information on the distance traveled by the worker W. The acquisition unit 10 outputs the acquired second information to the estimation unit 20.

[0035] The estimation unit 20 estimates the path taken by worker W within the positioning target area based on the second information output from the acquisition unit 10 and the first information pre-stored in the storage unit 40. The estimation unit 20 includes a floor estimation unit 21 and a path estimation unit 22.

[0036] The floor estimation unit 21 estimates the floor on which worker W is located within the positioning target area based on the atmospheric pressure acquired by sensor 200 included in the second information and the previously measured atmospheric pressure included in the first information. More specifically, the floor estimation unit 21 calculates the difference between the atmospheric pressure of a reference floor (in this embodiment, the 1st floor) and the atmospheric pressure of floors other than the 1st floor, among the atmospheric pressures measured on each floor of the positioning target area included in the first information. Next, the floor estimation unit 21 calculates a regression equation for determining the height from the 1st floor with atmospheric pressure as a variable by performing linear regression analysis on multiple sets of heights from the 1st floor and the calculated differences. The floor estimation unit 21 calculates the height at which worker W is located by substituting the atmospheric pressure measured by sensor 200 included in the second information into the regression equation, and estimates the floor on which worker W is located from that height.

[0037] The path estimation unit 22 estimates the path taken by worker W on the floor where worker W is located, as estimated by the floor estimation unit 21. The path estimation unit 22 comprises a first time series data generation unit 22A, a matching target path generation unit 22B, a matching target path identification unit 22C, a second time series data generation unit 22D, and a matching unit 22E.

[0038] The first time-series data generation unit 22A generates time-series data in which the magnetic fields measured by the sensor 200 are arranged in the order of measurement. The first time-series data generation unit 22A outputs the generated time-series data to the matching unit 22E.

[0039] The matching target path generation unit 22B generates multiple matching target paths that can be used for matching in the matching unit 22E, described later, by connecting at least some of the measurement points P located on the floor where worker W is located, as estimated by the floor estimation unit 21. Figure 2 shows an example of a matching target path generated by the matching target path generation unit 22B by connecting four measurement points P, enclosed in a dotted line. In Figure 2, three patterns of matching target paths generated by connecting four measurement points P are illustrated, but the matching target path generation unit 22B can also generate matching target paths connecting any other number of measurement points P. Furthermore, although Figure 2 only illustrates an example of connecting four measurement points P, the number of measurement points P included in a matching target path is not limited to four, and the matching target path generation unit 22B can generate matching target paths connecting any other number of measurement points P.

[0040] The matching route identification unit 22C identifies a matching route from among the multiple matching routes generated by the matching route generation unit 22B that has a length equivalent to the distance traveled by the worker W (in other words, the same length as the distance traveled by the worker W). Typically, there are multiple matching routes identified by the matching route identification unit 22C.

[0041] The second time-series data generation unit 22D generates time-series data for each of the matching target routes identified by the matching target route identification unit 22C, arranging the magnetic components in order along the route. The second time-series data generation unit 22D outputs the generated time-series data to the matching unit 22E.

[0042] The matching unit 22E estimates the path traveled by worker W by comparing (1) the change patterns of multiple magnetic fields included in the second information accompanying the movement of worker W with (2) the change patterns of magnetic fields of the target path identified by the matching target path identification unit 22C. In this embodiment, the matching unit 22E calculates the similarity between (1) the change patterns of multiple magnetic fields included in the second information accompanying the movement of worker W and (2) the change patterns of magnetic fields of the target path identified by the matching target path generation unit 22B, and estimates the path traveled by worker W based on this similarity. Details of the method for estimating the path traveled by worker W in this embodiment will be described later.

[0043] The identification unit 30 identifies the location of worker W based on the path that worker W traveled, as estimated by the estimation unit 20. Specifically, the identification unit 30 identifies the location of worker W as being near the point where worker W last measured magnetism along the path that worker W traveled, as estimated by the estimation unit 20.

[0044] (Positioning method) Next, a method for determining the location of worker W within the positioning target area in this embodiment will be described. Figure 4 is a flowchart showing an example of the position determination process in this embodiment.

[0045] As shown in Figure 4, the location determination process in this embodiment includes a first information generation step (step S1) and a positioning step (step S2). Note that the first information generation step (step S1) does not need to be performed every time positioning is performed; if the first information generation step (step S1) is performed only once, the location of the worker W can be determined thereafter by performing only the positioning step (step S2).

[0046] The first information generation step is the process of generating the first information used in the positioning step. Figure 5 is a flowchart showing an example of the processing in the first information generation step. As shown in Figure 5, in the first information generation step, the measuring cart 100 is first driven along the paths that the worker W may move along on each floor of the positioning target area. This measures magnetism and atmospheric pressure at multiple measurement points P (step S11, first magnetic component measurement step).

[0047] Next, the second measuring unit 140 of the measuring trolley 100 creates links connecting measurement points P that the worker W can move to on each floor of the positioning target area (step S12). These links include distance information between the measurement points P. Finally, the second measuring unit 140 outputs first information, including magnetic and atmospheric pressure measurements taken in advance at multiple measurement points in the positioning target area, position information for each measurement point, and the links created in step S12, to the positioning device 1, and the first information is stored in the storage unit 40 (step S13).

[0048] The positioning process is the process of determining the location of the worker W within the positioning target area using the positioning device 1. Figure 6 is a flowchart showing an example of the processing in the positioning process. As shown in Figure 6, in the positioning process, first, while the worker W moves a predetermined distance, the sensor 200 measures magnetism and atmospheric pressure at predetermined time intervals (step S21, second magnetic component measurement process).

[0049] Next, the acquisition unit 10 acquires first information from the sensor 200, which includes magnetic and atmospheric pressure measured by the sensor 200, as well as information on the distance traveled by the worker W (step S22).

[0050] Next, the floor estimation unit 21 estimates the floor on which worker W is located within the positioning target area based on the atmospheric pressure acquired from the sensor 200 (step S23). Specifically, the floor estimation unit 21 calculates the height at which worker W is located by substituting the atmospheric pressure measured by the sensor 200, which is included in the second information, into the regression equation created by the method described above, and estimates the floor on which worker W is located from that height.

[0051] Next, the first time-series data generation unit 22A generates time-series data by arranging the magnetic data measured by the sensor 200 in the order of measurement (step S24). The first time-series data generation unit 22A generates time-series data for both the horizontal and vertical components of the magnetic field in the global coordinate system. Hereafter, the time-series data generated by the first time-series data generation unit 22A will be referred to as the first time-series data.

[0052] Next, the matching path generation unit 22B generates multiple matching paths by connecting at least some of the consecutive measurement points P located on the floor where worker W is located, as estimated by the floor estimation unit 21 (step S25). "Connecting consecutive measurement points P" means connecting measurement points P by following the paths that are linked to each other in a structure (a so-called graph structure) where adjacent measurement points P that worker W can move to are connected by links. Specifically, the matching path generation unit 22B generates multiple matching paths based on the links for the floor where worker W is located, which were created in step S12.

[0053] Next, the matching target path identification unit 22C identifies a matching target path from among the multiple matching target paths generated by the matching target path generation unit 22B that has a length corresponding to the distance traveled by the worker W, based on the distance between measurement points P included in the link for the floor where the worker W is located, which was created in step S12 (step S26).

[0054] Next, the second time-series data generation unit 22D generates time-series data for each of the matching target routes identified by the matching target route identification unit 22C, by arranging them in order along the route, for both the horizontal and vertical components of the magnetism (step S27). Hereafter, the time-series data generated by the second time-series data generation unit 22D will be referred to as the second time-series data. The second time-series data generation unit 22D calculates the horizontal and vertical components of the magnetism measured by the sensor 200 in the global coordinate system using the angle between the sensor 200 and the ground surface, and generates the second time-series data using these components.

[0055] Next, the matching unit 22E calculates the similarity between the first time series data generated in step S24 and the second time series data generated in step S27, and estimates the path traveled by worker W based on this similarity (step S28, estimation step).

[0056] Specifically, the matching unit 22E calculates the time series data of the horizontal component of the first time series data as a=(a1, a2, ..., a i ), the time series data of the horizontal component of the second time series data is b=(b1, b2, ..., b i When this is the case, the distance d between the data points is calculated using the formula shown in Equation 1 below, and the similarity s is calculated by substituting the distance d between the data points into the formula shown in Equation 2 below. Hereafter, the similarity of the horizontal component will be described as s1.

number

[0057]

number

[0058] Furthermore, in this embodiment, a configuration using the similarity s calculated by the formula shown in Equation 2 above will be described, but this similarity s is just one example of similarity, and the matching unit 22E may calculate similarity using other formulas. When using the similarity s calculated by the formula shown in Equation 2 above, the similarity s is normalized to a value between 0 and 1, and the closer the similarity s is to 0, the lower the similarity between the time series data, and the closer the similarity s is to 1, the higher the similarity between the time series data. In addition, the matching unit 22E may also use the distance d between the data as the similarity.

[0059] The matching unit 22E calculates the similarity s for the vertical components of the first time series data and the second time series data, in the same way as the horizontal components. Hereafter, the similarity of the vertical components will be described as s2.

[0060] The matching unit 22E calculates the similarity between the first time series data and the second time series data for each of the matching target routes identified by the matching target route identification unit 22C, for both the horizontal and vertical components. The matching unit 22E then estimates that the matching target route identified by the matching target route identification unit 22C, the one with the largest sum of the similarity s1 of the horizontal component and the similarity s2 of the vertical component, is the route traveled by worker W.

[0061] Once the matching unit 22E estimates the path taken by worker W, the identification unit 30 identifies the location of worker W based on the path estimated by the estimation unit 20 (step S29). Specifically, the identification unit 30 identifies the location of worker W as being near the point where worker W last measured magnetism along the path estimated by the estimation unit 20.

[0062] As described above, the positioning device 1 of this embodiment calculates the similarity between a first time-series data generated using magnetism measured along the worker W's movement path and a second time-series data generated from above a previously measured magnetism, and estimates the path the worker W traveled based on this similarity. In other words, the positioning device 1 of this embodiment compares the pattern of change in magnetism accompanying the movement of the object to be positioned with the pattern of change in magnetism of a target path identified by connecting some or all of the measurement points among a plurality of measurement points where magnetism has been measured in advance, and estimates the path the worker W traveled. This improves the accuracy of estimating the path the worker W traveled from among a plurality of target paths. As a result, it is possible to improve the accuracy of estimating the worker W's position compared to the conventional method of estimating the position by comparing each point on a pre-created magnetic map with one magnetic data measured by a sensor held by the worker W.

[0063] In the above description, the matching unit 22E estimated the path traveled by worker W using the similarity of the horizontal and vertical components of the first time series data and the second time series data, but the present invention is not limited thereto. In one aspect of the present invention, the matching unit 22E may estimate the path traveled by worker W using either the horizontal or vertical component of the first time series data and the second time series data. However, by using the similarity of the horizontal and vertical components of the first and second time series data, the similarity between the first and second time series data can be calculated more accurately.

[0064] Here, due to the influence of the building structure as the positioning target area (e.g., the arrangement of steel frames, the devices placed there, etc.), the vertical component of the magnetic field may shift upward or downward depending on the height. As a result, using the horizontal component of the magnetic field rather than the vertical component of the magnetic field results in higher accuracy in estimating the path. Therefore, when using either the horizontal or vertical component of the first and second time series data, it is preferable to use the horizontal component.

[0065] Furthermore, in one aspect of the present invention, the matching unit 22E may estimate the path traveled by worker W as follows. Specifically, the matching unit 22E first calculates the similarity of the horizontal and vertical magnetic components of the first and second time series data for each of the matching target paths identified by the matching target path identification unit 22C. Next, the matching unit 22E ranks the matching target paths identified by the matching target path identification unit 22C in descending order of similarity of the horizontal component. Then, from among the matching target paths whose ranking of horizontal component similarity is above a predetermined ranking (for example, matching target paths ranked in the top 5 or higher), the matching target path with the largest sum of the similarity of the horizontal component s1 and the similarity of the vertical component s2 is used to estimate the path traveled by worker W. As a result, the path traveled by worker W is estimated from matching target paths with high similarity of the horizontal component, thus improving the accuracy of estimating the path traveled by worker W.

[0066] Furthermore, in one aspect of the present invention, the matching unit 22E may rank the matching target routes identified by the matching target route identification unit 22C in descending order of similarity to the horizontal and vertical components, assign a score according to the ranking, and estimate the route traveled by worker W by selecting the matching target route with the highest sum of the horizontal component score and the vertical component score. Also, as described above, since using the horizontal component of magnetism rather than the vertical component of magnetism results in higher accuracy in route estimation, the sum of the horizontal component score and the vertical component score may be calculated so that the weighting of the similarity of the horizontal component is greater, and the route traveled by worker W may be estimated.

[0067] As described above, the vertical component of magnetism may shift upward or downward depending on the height. Therefore, in one aspect of the present invention, the time series data generated by the first time series data generation unit 22A and the time series data generated by the second time series data generation unit 22D may be normalized in a predetermined manner, and then compared by the comparison unit 22E. Specifically, the data may be normalized so that the minimum and maximum values ​​of the components included in the first time series data and the second time series data are the same. This reduces the influence of component shifts due to differences in measurement heights when the height at which the magnetism is measured using the measuring trolley 100 in the first information generation process (step S11) is different from the height at which the sensor 200 measures the magnetism in step S21. As a result, the accuracy of estimating the path traveled by the worker W can be improved.

[0068] Furthermore, in the above description, the matching unit 22E calculated the distance d between data using the formula represented by Equation 1 above. That is, the above method calculated the distance d between data using the so-called Euclidean distance, but the present invention is not limited to this. In one aspect of the present invention, the distance between data may be calculated using dynamic time warping (DTW) or Pearson's product-moment correlation coefficient.

[0069] Dynamic time stretching is a method that calculates the distance between each point (i.e., the absolute value of the error) of two time series data by brute force, finds the path that minimizes the distance between the two time series data, and calculates the distance between the data based on the sum of the distances between each point in that path. When using dynamic time stretching, the distance between the data DTW(x, y) can be calculated as follows. Note that in this explanation, the time series data of the horizontal component of the first time series data is x = (x1, x2, ..., x N ), the time series data of the horizontal component of the second time series data is y=(y1, y2, ..., y M We will explain it assuming that ). In dynamic time stretching, first, the time t=w of the first time series data x is x And the time t=w of the second time series data yy The alignment with is w=(w x , w y ), and the entire alignment of the time series data is represented by the set W (W = {w1, w2, ···, w K}). The set W is defined to satisfy the following three conditions when w m =(w x m , w y m ). - (1) w x m-1 - w x m ≤ 1 and w y m-1 - w y m ≤ 1 (2) w x m-1 - w x m ≥ 0 and w y m-1 - w y m ≥ 0 (3) w1 = (1, 1) and w K = (N, M) At this time, the distance DTW(x, y) between the data can be calculated using the formula shown in Equation 3 below.

[0070]

Equation

[0071]

Equation

[0072] Furthermore, in one aspect of the present invention, the matching unit 22E may calculate the similarity s for the horizontal and vertical components of the magnetism using different methods. For example, the similarity s for the horizontal component of the magnetism may be calculated using dynamic time stretching, and the similarity s for the vertical component of the magnetism may be calculated using Euclidean distance. Note that when calculating the similarity s using dynamic time stretching, the similarity can be calculated even if the number of elements in the first time series data and the number of elements in the second time series data are different, so it is not necessary to perform downsampling as described above.

[0073] In this embodiment, a method for identifying the location of worker W has been described, but the present invention is not limited thereto. In one aspect of the present invention, an object other than a person (for example, an autonomous robot) may be used as the object to be positioned.

[0074] The present invention is not limited to the embodiments described above, and various modifications are possible within the scope of the claims. Embodiments obtained by appropriately combining the technical means disclosed in different embodiments are also included in the technical scope of the present invention. [Explanation of Symbols]

[0075] 1 Locating device 10 Acquisition Department 20 Estimation part 30 Specific section 100 Measuring trolley 120, 120A wheels 130 First Measurement Unit (First Recording Unit) 140 Second Measurement Unit (Second Recording Unit)

Claims

1. A positioning device that identifies the position of an object to be positioned within a positioning target area, An acquisition unit that, along the movement path of the object to be positioned within the positioning target area, acquires the magnitudes of multiple horizontal and vertical components of multiple magnetic fields measured at multiple locations while the object to be positioned is moving, and the distance traveled by the object to be positioned along the movement path, using sensors possessed by the object to be positioned. (1) The acquisition unit obtains the change patterns of the plurality of magnetic fields obtained by the acquisition unit in accordance with the movement of the object to be positioned, and (2) the comparison unit obtains the change patterns of the magnetic fields of the comparison unit that have a length corresponding to the distance traveled, by comparing these two sets of magnetic fields with the change patterns of the magnetic fields of the comparison unit that have a length corresponding to the distance traveled. A positioning device comprising: a positioning unit that identifies the position of the positioning object based on the path taken by the positioning object estimated by the estimation unit.

2. The estimation unit, The acquisition unit compares the change pattern of the horizontal magnetic component acquired by the acquisition unit with the change pattern of the horizontal magnetic component that was measured in advance along the comparison target path. The positioning device according to claim 1, which estimates the path taken by the object to be positioned based on the result of matching the change pattern of the horizontal component of the magnetic field.

3. The estimation unit, The acquisition unit compares the change patterns of the horizontal and vertical components of the magnetic field acquired by the acquisition unit with the change patterns of the horizontal and vertical components of the magnetic field measured in advance along the comparison target path. The positioning device according to claim 1, which estimates the path taken by the object to be positioned based on the results of matching the change patterns of the horizontal component of the magnetism and the results of matching the change patterns of the vertical component of the magnetism.

4. The positioning device according to any one of claims 1 to 3, wherein the estimation unit calculates the similarity between the pattern of change in magnetic components measured at multiple locations along the movement path and the pattern of change in magnetic components measured in advance at multiple measurement points along the comparison target path, and estimates the path along which the object to be positioned moved based on the similarity.

5. The estimation unit, The similarity is calculated for the horizontal and vertical components of the magnetic field, The location identification device according to claim 4, which estimates the path taken by the object to be positioned from among the multiple matching target paths whose ranking of the similarity of the horizontal component calculated for each of the matching target paths is equal to or greater than a predetermined ranking.

6. The positioning device according to any one of claims 1 to 5, wherein the estimation unit normalizes the magnetic components acquired by the acquisition unit and the previously measured magnetic components in a predetermined manner, and then compares the change patterns of the magnetic components.

7. A method for determining the position of an object to be positioned within a positioning target area, A first magnetic component measurement step involves pre-measuring the magnetic field of multiple measurement points in the positioning target area, A second magnetic component measurement step is performed in which, along the movement path of the object to be positioned within the positioning target area, the magnitudes of multiple horizontal and vertical magnetic components are measured at multiple locations using sensors possessed by the object to be positioned as it moves. (1) The change patterns of the plurality of magnets measured in the second magnetic component measurement step as the object to be positioned moves, and (2) A comparison target path is defined as a path identified by connecting at least some of the consecutive measurement points among the plurality of measurement points measured in the first magnetic component measurement step, and the change pattern of the magnets of the comparison target path having a length corresponding to the distance the object to be positioned moved in the second magnetic component measurement step is compared with the change pattern of the magnets of the comparison target path having a length corresponding to the distance the object to be positioned moved in the second magnetic component measurement step, thereby estimating the path the object to be positioned moved. A method for determining a location, comprising: a determination step of determining the location of the location to be determined based on the path taken by the location to be determined, which was estimated in the estimation step.

8. A measuring cart for measuring magnetism, Wheels and, A first recording unit that measures magnetism and records the measured magnetism and the time at which the magnetism was measured, The system includes a second recording unit that calculates the distance traveled by the measuring trolley from the amount of rotation of the wheels, and records the calculated distance traveled and the time the measuring trolley traveled. Multiple north-pole and south-pole magnets are arranged alternately at equal intervals along the circumference of the wheel on the inside of the wheel. The wheel is further provided with a Hall sensor located inside the wheel, which outputs different output values ​​when it detects the north pole magnet or the south pole magnet, respectively. A measuring trolley in which the amount of rotation of the wheels is calculated based on the number of times the output value output from the Hall sensor changes.

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