Positioning system and fixed station

Abstract

To measure an installation position of a fixed station with a high degree of accuracy without using a survey instrument.SOLUTION: A positioning system measures a position of a mobile station (21) by means of wireless communication between the mobile station (21) mounted on a mobile object (20) and a plurality of fixed stations (11) installed at a certain place. Each of the plurality of fixed stations (11) has an initial setting mode in which an own installation position is measured to store, as an operation mode. The fixed station (11) of the initial setting mode measures a distance between each of a plurality of wireless machines (31) that are arranged in a known relative positional relation and itself by means of wireless communication, and measures its own installation position on the basis of the distance between each of the plurality of wireless machines (31) and itself.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present disclosure relates to positioning systems, and more particularly to fixed stations that are installed at fixed locations. [Background technology]

[0002] There are known positioning systems that measure the position of a mobile station by wireless communication between the mobile station (a radio device mounted on a moving object) and multiple fixed stations (radio devices installed on the ground). A specific example of such a system is a railway positioning system in which a mobile station is mounted on a train and multiple fixed stations are installed at stations and on the tracks.

[0003] In such a positioning system, a mobile station detects the direction of arrival (AoA (Angle of Arrival)) of a radio signal transmitted from each fixed station, and calculates the position of the mobile station based on the direction of arrival of the radio signal from each fixed station and the installation location of each fixed station. Therefore, in order to measure the position of a mobile station, it is necessary to measure the installation location of each fixed station in advance. Furthermore, to maintain high accuracy in measuring the position of the mobile station, maintenance is required to periodically check for abnormalities in the installation location of each fixed station. Traditionally, the installation location of fixed stations has been measured by professional surveying engineers using surveying equipment. As a result, operating a positioning system has required a great deal of time and labor costs.

[0004] As a technology to solve this problem, Patent Document 1 below discloses a method for measuring the installation position of each fixed station, in which the installation position of each fixed station is measured from the height of the installation position of each fixed station (the vertical component of the installation position) and the direction of arrival of radio signals from each fixed station detected by a mobile station at two known points. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Japanese Patent Application Publication No. 2022-66992 Summary of the Invention [Problem to be solved by the invention]

[0006] The technology of Patent Document 1 can measure the installation position of a fixed station without using a surveying instrument, but it has the following problems. First, information on the height of the installation position of the fixed station is required. For example, if the fixed station is installed at a high altitude, it is difficult to accurately measure the height of the installation position of the fixed station. Also, it is necessary to accurately position the mobile station at two known points. Furthermore, it is difficult to achieve high accuracy in positioning using AoA compared to positioning using, for example, ToF (Time of Flight). Unless these problems can be resolved, it will be difficult to measure the installation position of a fixed station with high accuracy using the technology of Patent Document 1.

[0007] The present disclosure has been made to solve the above-mentioned problems, and aims to provide a technology for measuring the installation position of a fixed station of a positioning system with high accuracy without using a surveying instrument. [Means for solving the problem]

[0008] The positioning system according to the present disclosure is a positioning system that measures the position of a mobile station mounted on a moving body through wireless communication between the mobile station and multiple fixed stations installed at fixed locations, wherein each of the multiple fixed stations has an initial setting mode as an operating mode in which it measures and stores its own installation position, and the fixed station in the initial setting mode measures the distance between itself and each of multiple radio devices arranged in a known relative positional relationship through wireless communication, and measures its own installation position based on the distance between each of the multiple radio devices and itself. [Effects of the Invention]

[0009] According to the present disclosure, the installation position of a fixed station of a positioning system can be measured with high accuracy without using a surveying instrument. [Brief explanation of the drawings]

[0010] [Figure 1]1 is a diagram for explaining the configuration of a positioning system according to a first embodiment and a method for measuring the installation positions of fixed stations. [Figure 2] FIG. 2 is a diagram illustrating an example of the configuration of a fixed station according to the first embodiment. [Figure 3] 3A and 3B are diagrams showing an example of an initial setting jig according to the first embodiment. [Figure 4] FIG. 10 is a diagram for explaining a modified example of the method for measuring the installation position of a fixed station according to the first embodiment. [Figure 5] FIG. 10 is a diagram for explaining a modified example of the method for measuring the installation position of a fixed station according to the first embodiment. [Figure 6] FIG. 10 is a diagram for explaining a modified example of the method for measuring the installation position of a fixed station according to the first embodiment. [Figure 7] 6 is a flowchart showing an operation in an initial setting mode of the fixed station according to the first embodiment. [Figure 8] 10 is a flowchart showing an operation in a maintenance mode of the fixed station according to the second embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0011] <First Embodiment> Fig. 1 shows the configuration of a positioning system according to the first embodiment. The positioning system according to the first embodiment is a positioning system for railways. However, the positioning system may be any system that includes a mobile station mounted on a moving object and multiple fixed stations fixed at certain locations.

[0012] 1, the positioning system according to the first embodiment includes a plurality of fixed stations 11, which are radio devices installed in a railway station 10, and a mobile station 21, which is a radio device mounted on a train 20. Here, it is assumed that a first fixed station 11a, a second fixed station 11b, a third fixed station 11c, and a fourth fixed station 11d are installed in the station 10 as the plurality of fixed stations 11. However, the number of fixed stations 11 installed in the station 10 is not limited to four.

[0013] In this embodiment, the installation positions of the multiple fixed stations 11 are represented in a reference coordinate system with a predetermined reference coordinate position as the origin. The reference coordinate position serving as the origin may be a point within the station 10 (for example, a specified stopping position of the train 20) or a point outside the station 10. The absolute position (latitude, longitude, altitude, etc.) of the reference coordinate position may be known or unknown. Hereinafter, a position represented in the reference coordinate system will be referred to as a "coordinate position."

[0014] A parameter (i.e., an offset from a reference coordinate position) representing its own coordinate position is set in each of the multiple fixed stations 11. Hereinafter, the coordinate position of the fixed station 11 itself set in the fixed station 11 may also be referred to as the "initial coordinate position." In the "operation mode," which is the operating mode during operation of the positioning system, the fixed station 11 transmits a radio signal including information about its own coordinate position (initial coordinate position) to the mobile station 21 and other fixed stations 11.

[0015] The radio signal transmitted from the fixed station 11 is used to measure the position of the mobile station 21, i.e., the position of the train 20. For example, the mobile station 21 can measure the position of the mobile station 21 based on the directions of arrival (AoA) of radio signals received from multiple fixed stations 11 (here, the first fixed station 11a, the second fixed station 11b, the third fixed station 11c, and the fourth fixed station 11d) and the coordinate positions of each fixed station 11 contained in the radio signals. The positioning method of the mobile station 21 may be the same as that of the conventional technology, and therefore a detailed description thereof will be omitted.

[0016] 2 is a diagram showing an example of the configuration of the fixed station 11. The first fixed station 11a, the second fixed station 11b, the third fixed station 11c, and the fourth fixed station 11d are all realized with the same configuration as that shown in FIG.

[0017] 2, the base station 11 includes an antenna 101, a transmitter 102, a receiver 103, and a controller 104. The transmitter 102 transmits a radio signal through the antenna 101, and the receiver 103 receives the radio signal through the antenna 101. The operations of the transmitter 102 and the receiver 103 are controlled by the controller 104.

[0018] The control unit 104 stores parameters that represent the coordinate position of the base station 11. For example, when positioning the mobile station 21 by AoA, the control unit 104 controls the transmission unit 102 to transmit a radio signal including information on the coordinate position of the base station 11 to the mobile station 21.

[0019] The following describes the positioning of the fixed station 11 that is performed prior to the start of operation of the positioning system. Here, a method for measuring the installation location of the first fixed station 11a will be described as a representative example. It is also assumed that the first fixed station 11a, the second fixed station 11b, the third fixed station 11c, and the fourth fixed station 11d have already been installed at the station 10, but that parameters representing their own coordinate positions (initial coordinate positions) have not yet been set.

[0020] When positioning the first fixed station 11a, a jig 30 for setting an initial coordinate position (hereinafter referred to as "initial setting jig 30") is installed at the station 10, as shown in Fig. 1. The radio 31 can be realized with a configuration similar to that shown in Fig. 2, for example. In other words, the radio 31 and the fixed station 11 may be radios with the same configuration.

[0021] As shown in Fig. 3, multiple radio devices 31 are attached to the initial setting jig 30 in a known relative positional relationship. For example, as shown in Fig. 3, if the initial setting jig 30 is a cube or a rectangular parallelepiped, Δx, Δy, and Δz are known values. As long as the relative positional relationship of the multiple radio devices 31 is known, the shape of the initial setting jig 30 may be any shape.

[0022] The initial setting jig 30 is installed so that at least one of the wireless devices 31 is placed at a known coordinate position (i.e., a position with a known offset from a reference coordinate position). For example, one of the wireless devices 31 may be placed at the reference coordinate position.

[0023] The operation mode of the first base station 11a can be switched by a user (e.g., an administrator of the positioning system) to an "initial setting mode," which is an operation mode for setting an initial coordinate position. Alternatively, the first base station 11a may automatically switch to the initial setting mode when the initial coordinate position has not yet been set.

[0024] 1, the first base station 11a operating in the initial setting mode performs wireless communication with multiple radios 31 on the initial setting jig 30, and measures the distance between the first base station 11a and each radio 31, for example, by ToF (Time of Flight). If the distance between the first base station 11a and three or more radios 31 is known, the relative positional relationship of the first base station 11a with respect to each radio 31 can be determined by so-called triangulation. Therefore, three or more radios 31 are provided on the initial setting jig 30.

[0025] As described above, at least one of the multiple radios 31 on the initial setting jig 30 is placed at a known coordinate position, and the relative positional relationship of the multiple radios 31 is also known. Therefore, if the relative positional relationship of the first base station 11a with respect to each radio 31 is known, the coordinate position of the first base station 11a can be determined. The control unit 104 of the first base station 11a calculates the coordinate position of the first base station 11a from the relative positional relationship of the first base station 11a with respect to each radio 31 obtained by triangulation, and sets the calculated coordinate position as the initial coordinate position of the first base station 11a.

[0026] The second fixed station 11b, the third fixed station 11c, and the fourth fixed station 11d can also be positioned in the same manner as the first fixed station 11a, using the initial setting jig 30. However, once the setting of the initial coordinate position of any of the fixed stations 11 has been completed (i.e., once the coordinate position of any of the fixed stations 11 has become known), the fixed station 11 whose initial coordinate position has been set may be used instead of the radio 31 on the initial setting jig 30.

[0027] For example, when setting the initial coordinate position of the second base station 11b after the setting of the initial coordinate position of the first base station 11a has been completed (i.e., after the coordinate position of the first base station 11a has become known), the second base station 11b may perform wireless communication with two radio devices 31 and the first base station 11a, as shown in FIG. 4, measure the distance between the second base station 11b and each of the two radio devices 31, and the distance between the second base station 11b and the first base station 11a, and calculate the coordinate position of the second base station 11b by triangulation.

[0028] Furthermore, when setting the initial coordinate position of the third fixed station 11c after the setting of the initial coordinate positions of the first fixed station 11a and the second fixed station 11b has been completed (i.e., after the coordinate positions of the first fixed station 11a and the second fixed station 11b have become known), the third fixed station 11c may perform wireless communication with one wireless device 31, the first fixed station 11a, and the second fixed station 11b, as shown in FIG. 5, measure the distance between the third fixed station 11c and the one wireless device 31, the distance between the third fixed station 11c and the first fixed station 11a, and the distance between the third fixed station 11c and the second fixed station 11b, and calculate the coordinate position of the third fixed station 11c by triangulation.

[0029] Furthermore, when setting the initial coordinate position of the fourth base station 11d after the setting of the initial coordinate positions of the first base station 11a, the second base station 11b, and the third base station 11c has been completed (i.e., after the coordinate positions of the first base station 11a, the second base station 11b, and the third base station 11c have become known), the initial setting jig 30 does not need to be used. That is, as shown in FIG. 6, the fourth base station 11d may perform wireless communication with the first base station 11a, the second base station 11b, and the third base station 11c, measure the distance between the fourth base station 11d and the first base station 11a, the distance between the fourth base station 11d and the second base station 11b, and the distance between the fourth base station 11d and the third base station 11c, and calculate the coordinate position of the fourth base station 11d by triangulation.

[0030] In this way, by using the initial coordinate positions of other fixed stations 11 to locate the position of the fixed station 11, it becomes possible to locate the position of a fixed station 11 installed at a location far from the initial setting jig 30 (for example, a location outside the communication range of the radio 31), thereby reducing restrictions on the installation location of the fixed station 11. Another advantage is that, for example, when replacing one of multiple fixed stations 11, the initial coordinate position of the newly introduced fixed station 11 can be set without using the initial setting jig 30.

[0031] 7 is a flowchart showing the operation of the base station 11 in the initial setting mode. The operation of the base station 11 in the initial setting mode will be described below with reference to the flowchart in FIG.

[0032] When the operation mode of the fixed station 11 is switched to the initial setting mode (step S11), the fixed station 11 determines whether to automatically acquire an initial coordinate position (step S12). This determination is made by the user. For example, if a surveyor measures the position of the fixed station 1, it is determined not to automatically acquire the initial coordinate position (NO in step S12), and the fixed station 11 sets the coordinate position input by the user (the positioning result by the surveyor) as the initial coordinate position (step S13).

[0033] On the other hand, when it is determined to automatically acquire the initial coordinate position (YES in step S12), the fixed station 11 measures the distance to the wireless devices 31 or other fixed stations 11 by communicating (for example, by ToF) with the multiple wireless devices 31 on the initial setting jig 30 or other fixed stations 11 whose coordinate positions are known, and measures its own coordinate position by triangulation using these distances (step S14).Then, the fixed station 11 sets its own measured coordinate position (the positioning result by triangulation) as its initial coordinate position (step S15).

[0034] When the setting of the initial coordinate position is completed, the base station 11 transitions to the operation mode (step S16). In the operation mode, the base station 11 can transmit a radio signal including information of its own coordinate position (initial coordinate position) to the mobile station 21 or another base station 11.

[0035] As described above, the fixed station 11 according to the first embodiment can automatically measure its own coordinate position and set its initial coordinate position, thereby eliminating the need to measure the position of the fixed station 11 using a surveying instrument. Furthermore, the measurement of the fixed station 11 itself is performed by measuring the distance between the fixed station 11 and multiple wireless devices 31 or other fixed stations 11, and there is no need to measure the direction of arrival (AoA) of the radio signal. Therefore, the coordinate position of the fixed station 11 can be measured with high accuracy.

[0036] <Embodiment 2> In the second embodiment, a technique related to maintenance for maintaining the positioning accuracy of the positioning system of the first embodiment will be described.

[0037] In the second embodiment, the base station 11 has, as an operation mode, a "maintenance mode" for detecting deviation of the installation position due to disturbances, etc. Switching to the maintenance mode may be performed by the user or may be performed automatically by time synchronization.

[0038] 8 is a flowchart showing the operation of the base station 11 in the maintenance mode. The operation of the base station 11 in the maintenance mode will be described below with reference to the flowchart in FIG.

[0039] When the operation mode of the fixed station 11 is switched to the maintenance mode (step S21), the fixed station 11 measures the distance between itself and the other fixed station 11 by communicating with the other fixed station 11 operating in the operation mode (for example, by ToF) (step S22).

[0040] Furthermore, the fixed station 11 calculates the distance between itself and the other fixed station 11 (i.e., the distance between its own initial coordinate position and the initial coordinate position of the other fixed station 11) from the information on the initial coordinate position included in the radio signal received from the other fixed station 11 (step S23). For example, if the initial coordinate position of itself is set to coordinates (x1, y1, z1) and the initial coordinate position of the other fixed station 11 is set to coordinates (x2, y2, z2), the distance therebetween is calculated as follows: √{(x1-x2)2 +(y1-y2) 2 +(z1-z2) 2} is calculated as

[0041] There are no restrictions on the method by which a fixed station 11 in maintenance mode acquires information on the initial coordinate positions of other fixed stations 11. For example, a fixed station 11 in maintenance mode may acquire information on the initial coordinate positions of other fixed stations 11 from a server that stores the initial coordinate positions of each fixed station 11.

[0042] Thereafter, the base station 11 compares the measured value of the distance between itself and the other base station 11 obtained in step S22 with the calculated value of the distance between itself and the other base station 11 obtained in step S23, and checks whether the difference between the two is equal to or greater than a predetermined threshold (step S24). If the difference between the two is equal to or greater than the threshold, the base station 11 determines that an abnormality has occurred in the installation location of the other base station 11, and notifies the system (e.g., a higher-level device of the base station 11) of information about the other base station 11 (e.g., information that can identify the base station 11 whose installation location has become abnormal, such as a unique number) (step S25).

[0043] After performing steps S22 to S25 for all other base stations 11, the base station 11 transitions to the operation mode (step S26).

[0044] The process of FIG. 8 is preferably performed in turn in all the base stations 11.

[0045] In this way, in the positioning system of the second embodiment, the fixed station 11 in the maintenance mode can detect deviations in the installation positions of the other fixed stations 11, which makes it easier to maintain the positioning system.

[0046] 8, a base station 11 in maintenance mode determines whether or not the installation positions of other base stations 11 are abnormal, assuming that its own installation position is normal. However, there is a risk that deviations may occur in the installation positions of the base stations 11 in maintenance mode. Therefore, for example, if the number of base stations 11 in which an abnormality in their installation positions is detected exceeds a certain value (e.g., half), the base station 11 in maintenance mode may determine that an abnormality has occurred in its own installation position and notify the system to that effect.

[0047] Furthermore, when the fixed station 11 in maintenance mode determines whether or not an abnormality has occurred in its own installation position, the target for which the fixed station 11 in maintenance mode determines the distance from itself in steps S22 and S23 may be any radio device as long as its coordinate position is known (for example, it may be a mobile station 21 or a radio device 31 installed on the initial setting jig 30).

[0048] It is possible to freely combine the embodiments, and to modify or omit the embodiments as appropriate.

[0049] <Additional Notes> Various aspects of the present disclosure are summarized below as appendices.

[0050] (Appendix 1) A positioning system that measures the position of a mobile station mounted on a moving object by wireless communication between the mobile station and a plurality of fixed stations installed at certain locations, each of the plurality of fixed stations has an initial setting mode as an operation mode in which it measures and stores its own installation position; The fixed station in the initial setting mode Measure the distance between the device itself and each of a plurality of wireless devices arranged in a known relative positional relationship by wireless communication; measuring the installation position of the wireless device based on the distance between the wireless device and the wireless device itself; Positioning system.

[0051] (Appendix 2) further comprising an initial setting jig to which a plurality of the radio devices are fixed, 1. A positioning system as described in Appendix 1.

[0052] (Appendix 3) the plurality of radios includes one or more of the plurality of fixed stations; 1. A positioning system according to claim 1 or 2.

[0053] (Appendix 4) A fixed station in a positioning system that measures the position of a mobile station mounted on a moving object through wireless communication between the mobile station and a plurality of fixed stations installed at certain locations, As an operation mode, there is an initial setting mode in which the device measures and stores its own installation position, In the initial setting mode, Measure the distance between the device itself and each of a plurality of wireless devices arranged in a known relative positional relationship by wireless communication; measuring the installation position of the wireless device based on the distance between the wireless device and the wireless device itself; Fixed station.

[0054] (Appendix 5) The plurality of radios includes other fixed stations. Fixed stations as described in Appendix 4.

[0055] (Appendix 6) A positioning system that measures the position of a mobile station mounted on a moving object by wireless communication between the mobile station and a plurality of fixed stations installed at certain locations, each of the plurality of fixed stations has a maintenance mode as an operation mode for detecting abnormalities in the installation position of the fixed station itself or other fixed stations; The fixed station in the maintenance mode acquire a measurement value that measures the distance between the other fixed station and the own station by wireless communication; obtain a calculated value of the distance between the other fixed station and the own station, calculated from information on the installation positions of both stations; If the difference between the measured value and the calculated value is equal to or greater than a predetermined threshold, it is determined that an abnormality has occurred in the installation location of the own or the other fixed station. Positioning system.

[0056] (Appendix 7) A fixed station in a positioning system that measures the position of a mobile station mounted on a moving object through wireless communication between the mobile station and a plurality of fixed stations installed at certain locations, As an operation mode, it has a maintenance mode for detecting abnormalities in the installation position of its own or other fixed stations, In the maintenance mode, acquire a measurement value that measures the distance between the other fixed station and the own station by wireless communication; obtain a calculated value of the distance between the other fixed station and the own station, calculated from information on the installation positions of both stations; If the difference between the measured value and the calculated value is equal to or greater than a predetermined threshold, it is determined that an abnormality has occurred in the installation location of the own or the other fixed station. Fixed station. [Explanation of symbols]

[0057] 10 Station, 11 Fixed station, 11a First fixed station, 11b Second fixed station, 11c Third fixed station, 11d Fourth fixed station, 20 Train, 21 Mobile station, 30 Initial setting jig, 31 Radio, 101 Antenna, 102 Transmitter, 103 Receiver, 104 Control unit.

Claims

1. A positioning system that measures the position of a mobile station mounted on a moving object by wireless communication between the mobile station and a plurality of fixed stations installed at certain locations, each of the plurality of fixed stations has an initial setting mode as an operation mode in which it measures and stores its own installation position; The fixed station in the initial setting mode Measure the distance between the device itself and each of a plurality of wireless devices arranged in a known relative positional relationship by wireless communication; measuring the installation position of the wireless device based on the distance between the wireless device and the wireless device itself; Positioning system.

2. further comprising an initial setting jig to which a plurality of the radio devices are fixed, The positioning system of claim 1 .

3. the plurality of radios includes one or more of the plurality of fixed stations; 3. The positioning system according to claim 1 or 2.

4. A fixed station in a positioning system that measures the position of a mobile station mounted on a moving object through wireless communication between the mobile station and a plurality of fixed stations installed at certain locations, As an operation mode, there is an initial setting mode in which the device measures and stores its own installation position, In the initial setting mode, Measure the distance between the device itself and each of a plurality of wireless devices arranged in a known relative positional relationship by wireless communication; measuring the installation position of the wireless device based on the distance between the wireless device and the wireless device itself; Fixed station.

5. The plurality of radios includes other fixed stations.

5. The fixed station according to claim 4.

6. A positioning system that measures the position of a mobile station mounted on a moving object by wireless communication between the mobile station and a plurality of fixed stations installed at certain locations, each of the plurality of fixed stations has a maintenance mode as an operation mode for detecting abnormalities in the installation position of the fixed station itself or other fixed stations; The fixed station in the maintenance mode acquire a measurement value that measures the distance between the other fixed station and the own station by wireless communication; obtain a calculated value of the distance between the other fixed station and the own station, calculated from information on the installation positions of both stations; If the difference between the measured value and the calculated value is equal to or greater than a predetermined threshold, it is determined that an abnormality has occurred in the installation location of the own or the other fixed station. Positioning system.

7. A fixed station in a positioning system that measures the position of a mobile station mounted on a moving object through wireless communication between the mobile station and a plurality of fixed stations installed at certain locations, As an operation mode, it has a maintenance mode for detecting abnormalities in the installation position of its own or other fixed stations, In the maintenance mode, acquire a measurement value that measures the distance between the other fixed station and the own station by wireless communication; obtain a calculated value of the distance between the other fixed station and the own station, calculated from information on the installation positions of both stations; If the difference between the measured value and the calculated value is equal to or greater than a predetermined threshold, it is determined that an abnormality has occurred in the installation location of the own or the other fixed station. Fixed station.

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