Positioning system, positioning method, and reception tag

Abstract

A positioning system (1) measures the position of a reception tag (3) that moves between a first space where a first radio wave emitted from a first transmitter (2A) can be demodulated and a second space where the first radio wave cannot be demodulated. The positioning system (1) comprises: a second transmitter (2B) that emits a second radio wave which cannot be demodulated in the first space; a movement detection unit (53) that detects movement of the reception tag (3) on the basis of the demodulation states of the first radio wave and the second radio wave at the reception tag (3); and a position determination unit (54) that determines the position of the reception tag (3) using the first radio wave when the reception tag (3) is positioned in the first space and determines the position of the reception tag (3) using the second radio wave when the reception tag (3) is positioned in the second space. Therefore, the present invention can provide the positioning system (1), a positioning method, and the reception tag (3) that make it possible to continue appropriate positioning even when the reception tag (3) moves between a space where a prescribed radio wave can be demodulated and a space where the prescribed radio wave cannot be demodulated.

Description

Positioning system, positioning method, and receiving tag

[0001] The present invention relates to a positioning system capable of measuring the position of a receiving tag, a positioning method, and a receiving tag.

[0002] Positioning methods using radio waves from positioning satellites such as GPS (Global Positioning System) satellites and GNSS (Global Navigation Satellite System) satellites are commonly used in various fields. However, when using radio waves from positioning satellites, positioning becomes impossible under conditions where the radio waves from the positioning satellites cannot reach. Therefore, a technology has been proposed in which the position of a device body is determined based on a GPS signal included in the radio waves from the positioning satellites, and under conditions where the radio waves from the positioning satellites cannot reach, an autonomous positioning means equipped with various sensors such as a geomagnetic sensor and an acceleration sensor integrates the direction and amount of movement with position data determined based on the GPS signal (see Patent Document 1).

[0003] JP 2013-15209 A

[0004] However, with the technology disclosed in Patent Document 1, if the period during which radio waves from a satellite do not reach is short, the accumulation of errors that occurs in the process of accumulating the direction of movement and amount of movement acquired by the autonomous positioning means does not pose a problem. However, if the period during which the vehicle stays in a space where radio waves from a satellite do not reach is long, the problem of accumulated errors becomes significant, and there is a problem that positioning cannot be performed properly in a space where radio waves from a satellite do not reach.

[0005] The present invention aims to provide a positioning system, a positioning method, and a receiving tag that can continue to perform proper positioning even when the receiving tag moves between a space where a specified radio wave can be demodulated and a space where the specified radio wave cannot be demodulated.

[0006] (1) The present invention is a positioning system for measuring the position of a receiving tag moving between a first space in which a first radio wave emitted from a first transmitter can be demodulated and a second space in which the first radio wave cannot be demodulated, the system comprising: a second transmitter disposed in the second space and emitting a second radio wave that cannot be demodulated in the first space; a first calculation unit that performs positioning calculations to measure the position of the receiving tag in a virtual first horizontal plane set in the first space based on the reception result of the first radio wave emitted from the first transmitter at the receiving tag; and a positioning calculation unit that performs positioning calculations to measure the position of the receiving tag in a virtual second horizontal plane set in the second space based on the reception result of the second radio wave emitted from the second transmitter at the receiving tag. a movement detection unit that detects movement of the receiving tag between the first space and the second space based on the demodulation status of the first radio wave and the second radio wave in the receiving tag; and a position determination unit that determines the position of the receiving tag based on the calculation result of the first calculation unit when it is determined based on the detection result of the movement detection unit that the receiving tag is located in the first space and not in the second space, and that determines the position of the receiving tag based on the calculation result of the second calculation unit when it is determined based on the detection result of the movement detection unit that the receiving tag is located in the second space and not in the first space.

[0007] In the present invention, a "receiving tag" refers to a positioning target that can receive radio waves, and a "transmitter" refers to an object that serves as a reference position when positioning using radio waves. Furthermore, a "receiving tag" may be capable of transmitting radio waves in addition to receiving them, and a "transmitter" may be capable of receiving radio waves in addition to transmitting them.

[0008] In the present invention, "a second space in which the first radio wave cannot be demodulated" means both a case in which the first radio wave cannot be demodulated in the entire second space and a case in which the first radio wave cannot be demodulated in a part of the second space, and "a first space in which the second radio wave cannot be demodulated" means both a case in which the second radio wave cannot be demodulated in the entire first space and a case in which the second radio wave cannot be demodulated in a part of the first space.

[0009] (2) In the present invention, it is preferable that an overlapping space exists where the first space and the second space overlap, and when the position determination unit determines that the receiving tag is located in the overlapping space based on the detection result of the movement detection unit, it determines the position of the receiving tag based on both the calculation result of the first calculation unit and the calculation result of the second calculation unit.

[0010] (3) In the present invention, when the position determination unit determines, based on the detection result of the movement detection unit, that the receiving tag is located in one of the first space and the second space and that the receiving tag is not located in the other space, it is preferable to stop calculations in the calculation unit corresponding to the other space, out of the first calculation unit and the second calculation unit.

[0011] (4) In the present invention, when the position determination unit determines, based on the detection result of the movement detection unit, that the receiving tag is moving from one space to the other space, it is preferable that the position determination unit resumes the calculation in the calculation unit that had been stopped.

[0012] (5) In the present invention, the first space and the second space are adjacent or partially overlapping in the movement path of the receiving tag, and when the position determination unit determines that the receiving tag has entered the second space from the first space side based on the detection result of the movement detection unit, it is preferable that the position determination unit determines the initial position of the receiving tag in the second horizontal plane based on the calculation result of the first calculation unit, and causes the second calculation unit to perform positioning calculations using the determined initial position in the second horizontal plane.

[0013] (6) In the present invention, when the position determination unit determines that the receiving tag has entered the first space from the second space side based on the detection result of the movement detection unit, it is preferable that the position determination unit determines the initial position of the receiving tag in the first horizontal plane based on the calculation result of the second calculation unit, and causes the first calculation unit to perform positioning calculations using the determined initial position in the first horizontal plane.

[0014] (7) In the present invention, it is preferable that the first transmitter is a positioning satellite located in the first space, and the second transmitter is a base station located in the second space.

[0015] (8) In the present invention, it is preferable that the first transmitter is a base station located in the first space, and the second transmitter is a base station located in the second space.

[0016] (9) In the present invention, it is preferable that the receiving tag comprises a first receiving unit that receives and demodulates the first radio wave, a second receiving unit that receives and demodulates the second radio wave, the first calculation unit, the second calculation unit, the movement detection unit, and the position determination unit.

[0017] (10) In the present invention, it is preferable that the receiving tag comprises a first receiving unit that receives and demodulates the first radio wave and a second receiving unit that receives and demodulates the second radio wave, and that the movement detection unit, the first calculation unit, the second calculation unit, and the position determination unit are provided in a management center that is capable of wireless communication with the receiving tag.

[0018] (11) The present invention is a positioning method for measuring the position of a receiving tag moving between a first space in which a first radio wave emitted from a first transmitter can be demodulated and a second space in which the first radio wave cannot be demodulated, the method comprising: providing a second transmitter in the second space for emitting a second radio wave that cannot be demodulated in the first space; and performing a first calculation step of performing a positioning calculation to measure the position of the receiving tag in a virtual first horizontal plane set in the first space based on the reception result at the receiving tag of the first radio wave emitted from the first transmitter; and performing a second calculation step of performing a positioning calculation to measure the position of the receiving tag in a virtual second horizontal plane set in the second space based on the reception result at the receiving tag of the second radio wave emitted from the second transmitter. a movement detection process for detecting movement of the receiving tag between the first space and the second space based on the demodulation status of the first radio wave and the second radio wave at the receiving tag; and a tag position determination process for determining the position of the receiving tag based on the calculation result of the first calculation process when it is determined based on the detection result of the movement detection process that the receiving tag is located in the first space and not in the second space, and for determining the position of the receiving tag based on the calculation result of the second calculation process when it is determined based on the detection result of the movement detection process that the receiving tag is located in the second space and not in the first space.

[0019] (12) The present invention provides a receiving tag capable of measuring its own position as it moves between a first space in which a first radio wave emitted from a first transmitter can be demodulated and a second space in which the first radio wave cannot be demodulated, the receiving tag comprising: a first calculation unit that performs positioning calculations to measure the position in a virtual first horizontal plane set in the first space based on a reception result of the first radio wave emitted from the first transmitter; a second calculation unit that performs positioning calculations to measure the position in a virtual second horizontal plane set in the second space based on a reception result of a second radio wave that is emitted from a second transmitter disposed in the second space and cannot be demodulated in the first space; The tag is characterized by comprising a movement detection unit that detects movement of the receiving tag itself between the first space and the second space based on the demodulation status of the wave, and a position determination unit that determines the position of the receiving tag itself based on the calculation result of the first calculation unit when it is determined based on the detection result of the movement detection unit that the receiving tag itself is located in the first space and not in the second space, and that determines the position of the receiving tag itself based on the calculation result of the second calculation unit when it is determined based on the detection result of the movement detection unit that the receiving tag itself is located in the second space and not in the first space.

[0020] In the present invention, a first transmitter that emits a first radio wave is provided in a first space, and a second transmitter that emits a second radio wave is provided in a second space, and radio waves are used for both positioning in the first space and positioning in the second space. Therefore, since positioning is performed based on the first transmitter and the second transmitter in both the first space and the second space, even if the receiving tag stays in the second space for a long time, accumulation of errors that is a problem in autonomous navigation is unlikely to occur. Therefore, according to the present invention, it is possible to provide a positioning system, a positioning method, and a receiving tag that can continue to perform appropriate positioning even if the receiving tag moves and stays between the first space where the first radio wave can be demodulated and the second space where the first radio wave cannot be demodulated.

[0021] FIG. 1 is an explanatory diagram showing the basic concept of a positioning system 1 according to a first embodiment of the present invention. FIG. 2 is a block diagram showing the configuration of the positioning system 1 shown in FIG. 1. FIG. 3 is an explanatory diagram showing the basic concept of a positioning system 1 according to a second embodiment of the present invention. FIG. 4 is a block diagram showing the configuration of the positioning system 1 shown in FIG. 3. FIG. 4 is an explanatory diagram showing the basic concept of a hybrid positioning method 1a that can be employed in the present invention. FIG. 5 is a block diagram showing the basic configuration of the hybrid positioning method 1a shown in FIG. 5. FIG. 5 is an explanatory diagram showing the basic concept of a configuration example 1 of the hybrid positioning method 1a employed in the present invention. FIG. 7 is a block diagram showing the basic configuration of the hybrid positioning method 1a shown in FIG. 7. FIG. 8 is an explanatory diagram showing a positioning method in the hybrid positioning method 1a shown in FIG. 8. FIG. 9 is an explanatory diagram showing a case where the accuracy of the straight-line distance decreases in the hybrid positioning method 1a shown in FIG. 7. FIG. 10 is a flowchart showing an operation example of the hybrid positioning method 1a shown in FIG. 7. FIG. 11 is an explanatory diagram showing the results of evaluation 1 of the hybrid positioning method 1a shown in FIG. 7. FIG. 12 is an explanatory diagram showing a method of evaluation 2 of the hybrid positioning method 1a shown in FIG. 7. 14(A) is an explanatory diagram showing the results of evaluation 2 shown in FIG. 13 , where FIG. 14(A) is an explanatory diagram showing the time progression of the results of measuring the distance a in space between the transmitter 2 and the receiving tag 3 in evaluation 2, and FIG. 14(B) is an explanatory diagram showing the time progression of the results of calculating the angle θ that the line connecting the transmitter 2 and the receiving tag 3 in space makes with the horizontal plane 10 in evaluation 2. An explanatory diagram showing the results of measuring the position of the receiving tag 3 on a two-dimensional coordinate system in evaluation 2. An explanatory diagram of a configuration example 2 of the hybrid positioning method 1a adopted in the present invention. An explanatory diagram of a configuration example 4 of the hybrid positioning method 1a adopted in the present invention. A block diagram of the hybrid positioning method 1a shown in FIG. 17.

[0022] Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. In the embodiments described below, the term "second space B in which the first radio wave cannot be demodulated" refers to both a case in which the first radio wave cannot be demodulated in the entire second space B and a case in which the first radio wave cannot be demodulated in a part of the second space, and the term "first space A in which the second radio wave cannot be demodulated" refers to both a case in which the second radio wave cannot be demodulated in the entire first space A and a case in which the second radio wave cannot be demodulated in a part of the first space A.

[0023] [Embodiment 1] (Overall Configuration) Fig. 1 is an explanatory diagram showing the basic concept of a positioning system 1 according to embodiment 1 of the present invention. As shown in Fig. 1, the positioning system 1 according to embodiment 1 of the present invention is a so-called positioning system that measures the position of a receiving tag 3 that moves between a first space A where a first radio wave emitted from a first transmitter 2A reaches and a second space B where the first radio wave does not reach the entire space or part of the space. In other words, the positioning system 1 is a positioning system that measures the position of a receiving tag 3 that moves between the first space A where the first radio wave emitted from the first transmitter 2A can be demodulated and the second space B where the first radio wave cannot be demodulated.

[0024] More specifically, the positioning system 1 measures the position of a receiving tag 3 that moves between a first space A in which the first radio wave emitted from a first transmitter 2A and the second radio wave emitted from a second transmitter 2B can be demodulated throughout the entire space but the second radio wave can be demodulated only in a part of the space, and a second space B in which the second radio wave can be demodulated throughout the entire space but the first radio wave can be demodulated only in a part of the space.

[0025] The receiving tag 3 may be capable of transmitting the first and second radio waves in addition to receiving the first and second radio waves. The first transmitter 2A may be capable of receiving the first radio waves in addition to transmitting the first radio waves. The second transmitter 2B may be capable of receiving the second radio waves in addition to transmitting the second radio waves.

[0026] In the first embodiment, the first space A is an outdoor space, and the second space B is a space such as indoors, in a tunnel, or on a ship, where the first radio wave cannot be demodulated in some parts. The first transmitter 2A is a plurality of positioning satellites located in the first space A, and serves as a reference station for measuring the position of the receiving tag 3 in the first space A. The second transmitter 2B is a base station fixed in the second space B, and serves as a reference station for measuring the position of the receiving tag 3 in the second space B. Here, the base station means a fixed station capable of emitting radio waves.

[0027] When measuring the position of the receiving tag 3 in the first space A, the positioning system 1 measures the position of the receiving tag 3 within a virtual first horizontal plane 10A set in the first space A, and when measuring the position of the receiving tag 3 in the second space B, it measures the position of the receiving tag 3 within a virtual second horizontal plane 10B set in the second space B.

[0028] In the first embodiment, the first space A and the second space B partially overlap each other, and an overlap space C exists between the first space A and the second space B. In the overlap space C, the first radio wave and the second radio wave can be demodulated.

[0029] (Detailed Configuration) Fig. 2 is a block diagram showing the configuration of the positioning system 1 shown in Fig. 1. As shown in Fig. 2, the receiving tag 3 includes an antenna 34, a first receiving unit 31A that receives and demodulates the first radio wave, a first transmitting unit 32A that transmits the first radio wave, a first communication control unit 33A that controls the first receiving unit 31A and the first transmitting unit 32A, a second receiving unit 31B that receives and demodulates the second radio wave, a second transmitting unit 32B that transmits the second radio wave, and a second communication control unit 33B that controls the second receiving unit 31B and the second transmitting unit 32B.

[0030] The receiving tag 3 includes a first calculation unit 50A that performs positioning calculations to measure the position of the receiving tag 3 within a virtual first horizontal plane 10A set in the first space A based on the reception result of the first radio wave emitted from the first transmitter 2A at the receiving tag 3, and a second calculation unit 50B that performs positioning calculations to measure the position of the receiving tag 3 within a virtual second horizontal plane 10B set in the second space B based on the reception result of the second radio wave emitted from the second transmitter 2B at the receiving tag 3. The first calculation unit 50A and the second calculation unit 50B each perform positioning calculations at predetermined regular time intervals. Alternatively, the first calculation unit 50A and the second calculation unit 50B may perform positioning calculations irregularly.

[0031] The first horizontal plane 10A is set based on, for example, map information, and the position of the receiving tag 3 is identified as a position on the map. The second horizontal plane 10B is set within building information constructed using a digital twin or the like, and the measurement result of the position of the receiving tag 3 is identified as a position in a virtual space.

[0032] Since the first transmitter 2A is a plurality of positioning satellites such as GPS satellites and GNSS satellites located in the first space A, the first calculation unit 50A calculates the distance to each of the plurality of positioning satellites and the position of each of the plurality of positioning satellites based on the time information and identification signal contained in the first radio waves emitted from each of the plurality of positioning satellites, and performs positioning calculations to measure the position of the receiving tag 3 within the first horizontal plane 10A.

[0033] Since the second transmitter 2B is one base station arranged in the second space B, for positioning in the second space B, a hybrid positioning method 1a is adopted, which measures the position of the receiving tag 3 within the second horizontal plane 10B by using, for example, the straight-line distance between the base station and the receiving tag 3 calculated based on the time information included in the second radio wave and the detection results of a motion sensor or the like mounted on the receiving tag 3. Note that in the first embodiment, a plurality of second transmitters 2B may be arranged in the second space B.

[0034] The receiving tag 3 further includes a movement detection unit 53 that detects movement of the receiving tag 3 between the first space A and the second space B based on the demodulation status of the first radio wave and the second radio wave in the receiving tag 3.

[0035] More specifically, if the demodulation result of the first radio wave is such that positioning is possible, the movement detection unit 53 outputs a detection result that the receiving tag 3 is located in the first space A; if the demodulation result of the second radio wave is such that positioning is possible, the movement detection unit 53 outputs a detection result that the receiving tag 3 is located in the second space B; and if the demodulation result of the first radio wave and the second radio wave is such that positioning is possible, the movement detection unit 53 outputs a detection result that the receiving tag 3 is located in the overlapping space C.

[0036] The receiving tag 3 further includes a position determination unit 54 that determines the position of the receiving tag 3, and a storage unit 55 that stores past calculation results from the first calculation unit 50A and the second calculation unit 50B, and past positions of the receiving tag 3 determined by the position determination unit 54. The storage unit 55 may include either one memory or multiple memories.

[0037] In embodiment 1, the position determination unit 54, the movement detection unit 53, the first calculation unit 50A, and the second calculation unit 50B are configured as part of the functions of a microprocessor that operates based on a program pre-stored in a memory unit 55, etc., and the memory unit 55 stores the above-mentioned programs in addition to the calculation results of the first calculation unit 50A and the second calculation unit 50B, etc.

[0038] When the position determination unit 54 determines, based on the detection result of the movement detection unit 53, that the receiving tag 3 is located in the first space A and is not located in the second space B, the position determination unit 54 determines the position of the receiving tag 3 based on the calculation result of the first calculation unit 50A. On the other hand, when the position determination unit 54 determines, based on the detection result of the movement detection unit 53, that the receiving tag 3 is located in the second space B and is not located in the first space A, the position determination unit 54 determines the position of the receiving tag 3 based on the calculation result of the second calculation unit 50B.

[0039] In embodiment 1, since there is an overlapping space C where the first space A and the second space B overlap, when the position determination unit 54 determines, based on the detection result of the movement detection unit 53, that the receiving tag 3 is located in the overlapping space C, it determines the position of the receiving tag 3 based on both the calculation result of the first calculation unit 50A and the calculation result of the second calculation unit 50B.

[0040] For example, the position determination unit 54 compares the calculation result of the first calculation unit 50A with the calculation result of the second calculation unit 50B, and determines the calculation result with the shorter straight-line distance from the receiving tag 3 determined in the previous measurement as the position of the receiving tag 3 in the current measurement. Alternatively, the position determination unit 54 may determine the position of the receiving tag 3 to be midway between the calculation result of the first calculation unit 50A and the calculation result of the second calculation unit 50B.

[0041] Furthermore, when the position determination unit 54 determines, based on the detection result of the movement detection unit 53, that the receiving tag 3 is located in one of the first space A and the second space B and that the receiving tag 3 is not located in the other space, it stops the calculation in the calculation unit corresponding to the other space, out of the first calculation unit 50A and the second calculation unit 50B. Furthermore, when the position determination unit 54 determines, based on the detection result of the movement detection unit 53, that the receiving tag 3 is moving from one space to the other space, it restarts the calculation in the calculation unit that has stopped the calculation.

[0042] For example, when the position determination unit 54 determines that the receiving tag 3 is located in the first space A but not in the second space B, it stops the calculation in the second calculation unit 50B. On the other hand, when the position determination unit 54 determines, based on the detection result of the movement detection unit 53, that the receiving tag 3 is located in the second space B but not in the first space A, it stops the calculation in the first calculation unit 50A. This reduces power consumption in the receiving tag 3. Furthermore, when the position determination unit 54 determines, based on the detection result of the movement detection unit 53, that the receiving tag 3 has moved from the second space B other than the overlapping space C to the first space A as the overlapping space C, or when it determines that the receiving tag 3 has moved from the first space A other than the overlapping space C to the second space B as the overlapping space C, it resumes the calculation in the first calculation unit 50A or the second calculation unit 50B that was stopped.

[0043] Here, positioning in the second space B is performed using a hybrid positioning method 1a that uses one second transmitter 2B and a motion sensor. For example, the second calculation unit 50B performs the current positioning calculation of the receiving tag 3 using past calculation results of the second calculation unit 50B stored in the memory unit 55. Therefore, if the initial position in the second space B is unknown at the start of the calculation, the second calculation unit 50B cannot perform the positioning calculation. Therefore, when the position determination unit 54 determines that the receiving tag 3 has moved from the first space A to the second space B based on the detection result of the movement detection unit 53, it determines the initial position of the receiving tag 3 in the second horizontal plane 10B based on the current or previous calculation result of the first calculation unit 50A, and causes the second calculation unit 50B to perform the positioning calculation using the determined initial position in the second space B. This configuration is not limited to cases where an overlapping space C exists on the movement path of the receiving tag 3, but can also be adopted when the first space A and the second space B are adjacent to each other on the movement path of the receiving tag 3.

[0044] If the receiving tag 3 enters the second space B without performing positioning of the receiving tag 3, the receiving tag 3 is made to pass through a predetermined position in the second space B, and that predetermined position is set as the initial position.

[0045] In contrast, the first transmitter 2A is made up of multiple positioning satellites. In this case, the first calculation unit 50A can perform current positioning calculations for the receiving tag 3 based on the results of communication with the multiple positioning satellites, so there is no need to use past calculation results in the first calculation unit 50A to perform current positioning calculations for the receiving tag 3. Therefore, the first calculation unit 50A does not need the initial position of the receiving tag 3.

[0046] (Positioning method) The positioning method using the positioning system 1 of embodiment 1 is a positioning method for measuring the position of a receiving tag 3 moving between a first space A in which the first radio wave emitted from the first transmitter 2A can be demodulated and a second space B in which the first radio wave cannot be demodulated.First, a second transmitter 2B is provided in the second space B, which emits a second radio wave that can be demodulated in the second space B but cannot be demodulated in the space of the first space A.

[0047] Next, in the first calculation step, a positioning calculation is performed to measure the position of the receiving tag within a virtual first horizontal plane 10A set in the first space A based on the reception result at the receiving tag 3 of the first radio wave emitted from the first transmitter 2A, and in the second calculation step, a positioning calculation is performed to measure the position of the receiving tag 3 within a virtual second horizontal plane 10B set in the second space B based on the reception result at the receiving tag 3 of the second radio wave emitted from the second transmitter 2B.

[0048] In the movement detection step, movement of the receiving tag 3 between the first space A and the second space B is detected based on the demodulation status of the first radio wave and the second radio wave in the receiving tag 3.

[0049] Next, in the tag position determination process, when it is determined based on the detection results in the movement detection process that the receiving tag 3 is located in the first space A and not in the second space B, the position of the receiving tag 3 is determined based on the calculation results in the first calculation process, and when it is determined based on the detection results in the movement detection process that the receiving tag 3 is located in the second space B and not in the first space A, the position of the receiving tag 3 is determined based on the calculation results in the second calculation process.

[0050] (Major Effects of First Embodiment) As described above, in the positioning system 1 according to the first embodiment, a positioning satellite that emits a first radio wave is provided in the first space A as the first transmitter 2A, a base station that emits a second radio wave is provided in the second space B as the second transmitter 2B, and radio waves are used for positioning in both the first space A and the second space B. Therefore, in both the first space A and the second space B, positioning is performed based on the first transmitter 2A and the second transmitter 2B, so that even if the receiving tag 3 stays in the second space B for a long time, accumulation of errors that is a problem in autonomous navigation is unlikely to occur.

[0051] Therefore, according to embodiment 1, it is possible to provide a positioning system, a positioning method, and a receiving tag 3 that can seamlessly continue proper positioning even when the receiving tag 3 moves between a first space A in which the first radio wave can be demodulated and a second space B in which the first radio wave cannot be demodulated.

[0052] In addition, the movement detection unit 53 detects the movement of the receiving tag 3 between the first space A and the second space B based on the demodulation status of the first radio wave and the second radio wave at the receiving tag 3, and therefore can perform detection that is directly related to whether positioning is possible using the first radio wave and the second radio wave.

[0053] Furthermore, an overlapping space C is provided where the first space A and the second space B overlap, and when it is determined that the receiving tag 3 is located in the overlapping space C, the position of the receiving tag 3 is determined based on both the calculation results of the first calculation unit 50A and the calculation results of the second calculation unit 50B. Therefore, the position of the receiving tag 3 can be measured continuously and without interruption both when the receiving tag 3 moves from the first space A to the second space B and when the receiving tag 3 moves from the second space B to the first space A.

[0054] Furthermore, since the second calculation unit 50B is a calculation unit that uses past calculation results of the second calculation unit 50B to perform current positioning calculations for the receiving tag 3, positioning calculations cannot be performed without an initial position, but when the position determination unit 54 determines that the receiving tag 3 has moved from the first space A to the second space B, it determines the initial position of the receiving tag 3 in the second space B based on the calculation results of the first calculation unit 50A. Therefore, the second calculation unit 50B can perform positioning calculations using the determined initial position in the second space B.

[0055] Furthermore, in the positioning system 1 according to the first embodiment, a first radio wave from a positioning satellite (first transmitter 2A) is used in the first space A, and a second radio wave from a base station (second transmitter 2B) is used in the first space A. Therefore, if the second space B is the inside of a shopping center, it is possible to perform positioning continuously in the outdoors as the first space A and the inside of the shopping center as the second space B, and to provide guidance, etc.

[0056] If the second space B is a tunnel, the positioning system 1 can be used to assist a vehicle when traveling through the tunnel. If the second space B is a parking space on a ship, the positioning system 1 can be used to assist in guiding an outdoor vehicle to a parking space on the ship, or to guide an outdoor vehicle to a parking space on the ship using autonomous driving technology.

[0057] [Variation of Embodiment 1] In Embodiment 1, the case where the first space A and the second space B are adjacent to each other horizontally has been described. However, the present invention may also be applied to a case where, for example, the first space A is on the rooftop and the second space B is on the top floor indoors.

[0058] [Embodiment 2] Fig. 3 is an explanatory diagram showing the basic concept of a positioning system 1 according to embodiment 2 of the present invention. Fig. 4 is a block diagram showing the configuration of the positioning system 1 shown in Fig. 1. Note that the configuration of the receiving tag 3 shown in Fig. 4 is the same as that of embodiment 1, so the same reference numerals are used to designate common parts and detailed description thereof will be omitted.

[0059] As shown in Figure 3, the positioning system 1 of embodiment 2 of the present invention, like embodiment 1, is a positioning system that measures the position of a receiving tag 3 moving between a first space A in which the first radio wave emitted from a first transmitter 2A can be demodulated throughout the entire space, and a second space B in which the first radio wave cannot be demodulated.

[0060] In the second embodiment, both the first space A and the second space B are spaces such as indoors where radio waves from positioning satellites cannot be demodulated. Therefore, a base station is disposed in the first space A as a first transmitter 2A, and the first transmitter 2A serves as a reference station for measuring the position of the receiving tag 3 in the first space A. A base station is disposed in the second space B as a second transmitter 2B, and the second transmitter 2B serves as a reference station for measuring the position of the receiving tag 3 in the second space B.

[0061] In the second embodiment, the first space A and the second space B are located on different floors indoors. For example, the first space A may be the first floor indoors, and the second space B may be the second floor indoors. Alternatively, the first space A may be an underground space, and the second space B may be the first floor indoors. In either case, the first space A can demodulate the first radio wave emitted from the first transmitter 2A throughout the entire space, but the second radio wave emitted from the second transmitter 2B can be demodulated only in a portion of the space. The second space B can demodulate the second radio wave emitted from the second transmitter 2B throughout the entire space, but the first radio wave emitted from the first transmitter 2A can be demodulated only in a portion of the space. Here, the first space A and the second space B partially overlap in plan view by a staircase or the like, and the staircase is an overlapping space C in which both the first radio wave and the second radio wave can be demodulated.

[0062] As shown in Figure 4, the receiving tag 3 has a configuration similar to that of embodiment 1, including a first calculation unit 50A that performs positioning calculations to measure the position of the receiving tag 3 within a virtual first horizontal plane 10A set in the first space A based on the reception result at the receiving tag 3 of the first radio wave emitted from the first transmitter 2A, and a second calculation unit 50B that performs positioning calculations to measure the position of the receiving tag 3 within a virtual second horizontal plane 10B set in the second space B based on the reception result at the receiving tag 3 of the second radio wave emitted from the second transmitter 2B.

[0063] Here, since the first transmitter 2A and the second transmitter 2B are a single base station, one placed in each of the first space A and the second space B, for positioning in the first space A and the second space B, a hybrid positioning method 1a is adopted, which measures the position of the receiving tag 3 within the second horizontal plane 10B by utilizing, for example, the straight-line distance between the base station and the receiving tag 3 and the detection results of a motion sensor mounted on the receiving tag 3.

[0064] Therefore, the second calculation unit 50B is a calculation unit that performs current positioning calculations for the receiving tag 3 by using past calculation results of the second calculation unit 50B stored in the memory unit 55. Therefore, when the position determination unit 54 determines, based on the detection result of the movement detection unit 53, that the receiving tag 3 has moved from the first space A to the second space B, it determines the initial position of the receiving tag 3 in the second horizontal plane 10B based on the current or previous calculation result of the first calculation unit 50A, and causes the second calculation unit 50B to perform positioning calculations by using the determined initial position in the second space B.

[0065] Similarly to the second calculation unit 50B, the first calculation unit 50A is a calculation unit that performs current positioning calculations for the receiving tag 3 using past calculation results by the first calculation unit 50A stored in the memory unit 55. Therefore, when the position determination unit 54 determines, based on the detection result of the movement detection unit 53, that the receiving tag 3 has moved from the second space B to the first space A, it determines the initial position of the receiving tag 3 in the first horizontal plane 10A based on the current or previous calculation result by the second calculation unit 50B, and causes the first calculation unit 50A to perform positioning calculations using the determined initial position in the first space A.

[0066] This configuration is not limited to cases where an overlapping space C exists on the movement path of the receiving tag 3, but can also be employed when the first space A and the second space B are adjacent to each other on the movement path of the receiving tag 3. If the receiving tag 3 directly enters the second space B without performing positioning of the receiving tag 3, the receiving tag 3 is made to pass through a predetermined position in the second space B, and that predetermined position is set as the initial position. Also, if the receiving tag 3 directly enters the first space A without performing positioning of the receiving tag 3, the receiving tag 3 is made to pass through a predetermined position in the first space A, and that predetermined position is set as the initial position. The other configurations are the same as those of the first embodiment, so description thereof will be omitted.

[0067] As described above, in the positioning system 1 according to the second embodiment, as in the first embodiment, a positioning satellite that emits a first radio wave is provided in the first space A as the first transmitter 2A, a base station that emits a second radio wave is provided in the second space B as the second transmitter 2B, and radio waves are used for both positioning in the first space A and positioning in the second space B. Therefore, in both positioning in the first space A and positioning in the second space B, positioning is performed based on the first transmitter 2A and the second transmitter 2B, so that even if the receiving tag 3 stays in the second space B for a long time, the accumulation of errors that is a problem in autonomous navigation is less likely to occur, and similar effects to those of the first embodiment are achieved.

[0068] [Variation of Embodiment 2] In Embodiment 2, the case where the first space A and the second space B are on different floors has been described, but the present invention may also be applied to a case where the first space A and the second space B are adjacent to each other horizontally.

[0069] [Variant of embodiments 1 and 2] In embodiment 1, the receiving tag 3 is equipped with a first receiving unit 31A, a second receiving unit 31B, a first calculation unit 50A, a second calculation unit 50B, a movement detection unit 53, and a position determination unit 54. However, the receiving tag 3 may be equipped with a first receiving unit 31A and a second receiving unit 31B, and the first calculation unit 50A, the second calculation unit 50B, the movement detection unit 53, and the position determination unit 54 may be provided in a management center that is capable of wireless communication with the receiving tag 3.

[0070] [Basic Configuration of Hybrid Positioning Method 1a Using Base Station] A configuration example of the hybrid positioning method 1a described in Embodiments 1 and 2 will be described below. Note that the positioning method described below can be applied to the case where a base station is used as the second transmitter 2B in Embodiments 1 and 2, and can also be applied to the case where a base station is used as the first transmitter 2A in Embodiment 2. Therefore, in the following description, there will be no distinction between "first" and "second," and the first transmitter 2A and second transmitter 2B will be described simply as transmitters 2, for example.

[0071] (Basic Concept) Fig. 5 is an explanatory diagram showing the basic concept of a hybrid positioning method 1a that can be employed in the present invention. Fig. 6 is a block diagram showing the basic configuration of the hybrid positioning method 1a shown in Fig. 5.

[0072] In the positioning system 1 according to the first and second embodiments, the hybrid positioning method 1a shown in Fig. 5 includes a transmitter 2 and a receiving tag 3 capable of communicating with the transmitter 2 via radio waves, and measures the relative position of the receiving tag 3 with respect to the transmitter 2 within an imaginary horizontal plane 10 that is perpendicular to the vertical direction from the transmitter 2 and passes through the height position of the receiving tag 3. The receiving tag 3 is equipped with a sensor 60 that detects the movement of the receiving tag 3. The horizontal plane 10 is set in a space where radio waves from positioning satellites cannot be demodulated even outdoors, or indoors, and the positioning system 1 measures the position of the receiving tag 3 in a space where radio waves from positioning satellites cannot be demodulated.

[0073] The sensor 60 is a direction sensor such as a geomagnetic sensor, an acceleration sensor, a gyro sensor, etc., as will be described later with reference to Fig. 8. As the transmitter 2, a wireless communication device for UWB (Ultra-Wide Band), a wireless communication base station for mobile phones such as a fifth generation mobile communication system (5G), a wireless communication base station constituting an open RAN (Radio Access Network), a beacon, etc. can be used.

[0074] As will be described in more detail later, the hybrid positioning method 1a includes a distance calculation process that calculates the straight-line distance between the transmitter 2 and the receiving tag 3 within the horizontal plane 10 based on the radio wave reception results, and a relative position calculation process that determines the relative position of the receiving tag 3 within the horizontal plane 10 based on the straight-line distance and the detection results of the sensor 60.

[0075] 6, in the hybrid positioning method 1a, the transmitter 2 includes a receiving unit 21, a transmitting unit 22, a communication control unit 23, and an antenna 24. The transmitter 2 is a single unit.

[0076] In addition to the receiving unit 31, transmitting unit 32, communication control unit 33, and antenna 34, the receiving tag 3 includes a distance calculation unit 51 that calculates the linear distance between the transmitter 2 and the receiving tag 3 in the horizontal plane 10 based on the delay time when receiving radio waves from the transmitter 2, a sensor 60 that detects the movement of the receiving tag 3, and a data processing unit 65 that processes the output from the sensor 60. More specifically, the distance calculation unit 51 calculates the linear distance between the transmitter 2 and the receiving tag 3 in space based on the delay time in the radio wave reception results, and calculates the linear distance between the transmitter 2 and the receiving tag 3 in the horizontal plane 10 based on the calculation result.

[0077] The receiving tag 3 also has a position calculation unit 52 that calculates the relative position of the receiving tag 3 with respect to the transmitter 2 within the horizontal plane 10 based on the straight-line distance calculated by the distance calculation unit 51 and the detection results of the sensor 60, and the distance calculation unit 51 and the position calculation unit 52 form a calculation unit 50 for positioning calculations.

[0078] The receiving tag 3 also has a storage unit 55 consisting of a memory or the like that stores past calculation results and the like from the calculation unit 50. The storage unit 55 may have either one memory or multiple memories. The calculation unit 50 (distance calculation unit 51 and position calculation unit 52) ​​is configured as part of the functions of a microprocessor that operates based on a program pre-stored in the storage unit 55 or the like. The receiving tag 3 also has a display unit 36 ​​that displays the current relative position of the receiving tag 3 determined by the position calculation unit 52, and a control unit 35 that controls the entire receiving tag.

[0079] 6 shows a configuration in which the distance calculation unit 51, position calculation unit 52, etc. are provided in the receiving tag 3, and the distance calculation unit 51 calculates the straight-line distance in the receiving tag 3. Note that the distance calculation unit 51, position calculation unit 52, etc. may also be provided in a management center or the like that is provided separately from the receiving tag 3 and transmitter 2, in which case the management center and the receiving tag 3 can share information via wireless communication.

[0080] In either case, as shown in Figure 5, once the linear distance in space between the transmitter 2 and the receiving tag 3 is determined, the linear distance in space is represented as a sphere centered on the transmitter 2. However, in the positioning system 1 according to the present invention, in order to determine the relative position of the receiving tag 3 with respect to the transmitter 2 in a horizontal plane 10, the linear distance in space is represented as a circle where the sphere intersects with the horizontal plane 10. Therefore, if the movement of the receiving tag 3 detected by the sensor 60 is represented by a line on the horizontal plane 10, the intersection of the line and the circle will indicate the current position of the receiving tag 3 in two-dimensional coordinates. Note that in Figure 5, the movement of the receiving tag 3 detected by the sensor 60 is indicated by an arrow.

[0081] Therefore, by calculating the linear distance in the horizontal plane 10 (on two-dimensional coordinates) from the linear distance in space between the transmitter 2 and the receiving tag 3 based on the radio wave reception results, the relative position of the receiving tag 3 to the transmitter 2 in the horizontal plane 10 can be determined based on the linear distance calculation result and the result of detection of the movement of the receiving tag 3 by the sensor 60, so the relative position of the receiving tag 3 can be determined even if there is only one transmitter 2.

[0082] Furthermore, a wireless communication base station or the like that is installed in advance for use in wireless communication can be used as the transmitter 2 as it is, so there is no need to install the transmitter 2 solely for positioning. Therefore, it is possible to provide a positioning system 1 that can measure the position of the receiving tag 3 in a space where radio waves from a positioning satellite cannot be demodulated, without incurring a large cost for installing the transmitter 2.

[0083] [Configuration example 1 of hybrid positioning method 1a] Fig. 7 is an explanatory diagram showing the basic concept of configuration example 1 of hybrid positioning method 1a adopted in the present invention. Fig. 8 is a block diagram showing the basic configuration of hybrid positioning method 1a shown in Fig. 7. Fig. 9 is an explanatory diagram showing a positioning method in positioning system 1 shown in Fig. 8.

[0084] As shown in FIG. 7 , in configuration example 1 of the hybrid positioning method 1a employed in the present invention, the transmitter 2 is fixed in a space, such as indoors, where radio waves from positioning satellites cannot be demodulated, and the receiving tag 3 moves indoors. In the hybrid positioning method 1a, a virtual horizontal plane 10 is set that is perpendicular to the vertical direction from the transmitter 2 and passes through the height position of the receiving tag 3, and the relative position of the receiving tag 3 with respect to the transmitter 2 within this horizontal plane 10 is measured. By adding digital information about the structure to the horizontal plane 10, the number of transmitters 2 can be minimized. In configuration example 1, one transmitter 2 corresponds to the entire horizontal plane 10. Furthermore, the digital information about the structure refers to building information constructed using a digital twin, for example.

[0085] Here, the transmitter 2 is a mobile phone base station compatible with the fifth generation mobile communication system (5G), a communication device capable of two-way communication with the receiving tag 3 in an ultra-wideband, or a portable terminal having a communication function common to the receiving tag 3. Fig. 8 shows a configuration in which a communication device capable of two-way communication with the receiving tag 3 in an ultra-wideband is used as the transmitter 2.

[0086] 8, in the hybrid positioning method 1a, the transmitter 2 and the receiving tag 3 each include a communication module 20, 30 made by QORVO under the trade name DWM-1001-DEV. The communication modules 20, 30 each include a receiving unit 21, 31 equipped with an analog receiver or the like, a transmitting unit 22, 32 equipped with an analog transmitter or the like, and a communication control unit 23, 33 equipped with a controller or the like, and are capable of constructing a wireless network using a directional positioning reference signal (PRS).

[0087] In addition, the receiving tag 3 is equipped with a microprocessor that functions as a distance calculation unit 51 and a position calculation unit 52, and the memory unit 55 stores programs that operate the microprocessor, past calculation results in the distance calculation unit 51, and past calculation results in the position calculation unit 52, etc.

[0088] The receiving tag 3 is equipped with a three-axis geomagnetic sensor 67 as a sensor 60 that detects data for determining a directional vector within the horizontal plane 10 when the receiving tag 3 moves, and the position calculation unit 52 determines the relative position of the receiving tag 3 with respect to the transmitter 2 within the horizontal plane 10 based on the straight-line distance between the transmitter 2 and the receiving tag 3 within the horizontal plane 10 calculated by the distance calculation unit 51 and the directional vector detected by the geomagnetic sensor 67.

[0089] The receiving tag 3 further includes, as a sensor 60, an inertial sensor 61 that detects data for determining the distance traveled within the horizontal plane 10 when the receiving tag 3 moves, and the position calculation unit 52 determines the relative position using the travel distance and a direction vector under conditions where the accuracy of the linear distance decreases. In configuration example 1, the inertial sensor 61 is an acceleration sensor 68 for detecting the linear travel distance. Here, the geomagnetic sensor 67 and the acceleration sensor 68 require two axes corresponding to the horizontal plane 10, but the geomagnetic sensor 67 and the acceleration sensor 68 may each have three axes.

[0090] In configuration example 1, the receiving tag 3 is equipped with a 9-axis motion sensor 66 as the sensor 60, and the motion sensor 66 can supply data to the position calculation unit 52 via a single-board computer 62 equipped with a data processing unit 65. The 9-axis motion sensor 66 is equipped with a 3-axis geomagnetic sensor 67, a 3-axis acceleration sensor 68, and a 3-axis gyro sensor 69. In configuration example 1, only the 3-axis geomagnetic sensor 67 and the 3-axis acceleration sensor 68 are used, but the 3-axis gyro sensor 69 may also be used as an auxiliary sensor if necessary.

[0091] In the hybrid positioning method 1a configured in this way, the position calculation unit 52 determines the current relative position based on the straight-line distance calculated during the two previous and previous positioning operations, or the straight-line distance calculated backward from the relative positions determined during the two previous and previous operations, and the directional vector of the movement of the receiving tag 3 from the previous operation to the current operation. Therefore, if the initial position of the receiving tag 3 is unknown when starting positioning, the calculation unit 50 cannot perform positioning calculations, so for example, it makes the receiving tag 3 pass a predetermined position and sets that predetermined position as the initial position.

[0092] 7 and 9, the processing in the distance calculation unit 51 and the position calculation unit 52 will be described in detail. First, based on the reception result at the receiving tag 3, the linear distance connecting the receiving tag 3 and the transmitter 2 in space is found, and then the linear distance b between the transmitter 2 and the receiving tag 3 in the horizontal plane 10 is determined. This linear distance b is defined as a circle in the horizontal plane 10. This circle has a hypotenuse with a length equivalent to the linear distance a in space between the transmitter 2 and the receiving tag 3, and a radius equal to the length of the base of a right triangle whose height h is the distance between the horizontal plane 10 and the transmitter 2.

[0093] Therefore, if the linear distance from the intersection O of the vertical line from the transmitter 2 and the horizontal plane 10 to the receiving tag 3 is b, and the angle between the line connecting the receiving tag 3 and the transmitter 2 in space and the horizontal plane 10 is θ, the relationship between a, b, h, and θ is expressed by the following equations: b = a cos θ θ = arctan(b, h) h: height of the transmitter 2 when the horizontal plane 10, which corresponds to a two-dimensional coordinate system, is used as the reference a: linear distance between the transmitter 2 and the receiving tag 3 in space b: linear distance between the transmitter 2 and the receiving tag 3 in the horizontal plane 10 θ: angle between the line connecting the receiving tag 3 and the transmitter 2 and the horizontal plane 10

[0094] Therefore, if the distance a in space between the transmitter 2 and the receiving tag 3 is known based on the results of receiving the radio waves from the transmitter 2 at the receiving tag 3, the height h of the transmitter 2 is known, and so the straight-line distance b between the transmitter 2 and the receiving tag 3 in the horizontal plane 10 can be calculated.

[0095] Here, the relative position of the receiving tag 3 in the horizontal plane 10 is L, and the directional vector of the movement of the receiving tag 3 from the previous time to the current time detected by the geomagnetic sensor 67 is V. In FIG. 9, the current measurement result is marked with N, the previous measurement result is marked with N-1, and the measurement result before the previous one is marked with N-2. For example, if the current relative position is L, Ｎ The previous relative position is L Ｎ－１ The relative position two positions before is L Ｎ－２ Let's say.

[0096] Therefore, the previous relative position of the receiving tag 3 is L Ｎ－１ The direction vector of the movement of the receiving tag 3 from the previous time to the current time is V Ｎ When the previous relative position of the receiving tag 3 is L Ｎ－１ The direction vector V of movement from Ｎ When an imaginary straight line extending along the line is drawn, the linear distance a in the space of the receiving tag 3 is Ｎ The radius corresponding to the linear distance b Ｎ ) circle and direction vector V Ｎ The intersection point with the line indicating the current relative position L Ｎ This becomes:

[0097] Here, since there are multiple intersections, the relative position L Ｎ In such a case, the position calculation unit 52 selects the previous relative position L from among the multiple candidates. Ｎ－１ The candidate closest to the current relative position L Ｎ In this embodiment, since there are two intersections, the relative position L Ｎ Therefore, the position calculation unit 52 calculates the previous relative position L Ｎ－１ The candidate closest to the current relative position L Ｎ In Fig. 9, of the two candidates obtained in each of the previous and current positioning, the candidate closest to the relative position measured immediately before is indicated by a black circle (●), and the candidate farthest from the relative position measured immediately before is indicated by a white circle (O).

[0098] (Use of Travel Distance) Fig. 10 is an explanatory diagram of a case where the accuracy of the straight-line distance decreases in the hybrid positioning method 1a shown in Fig. 7. As shown in Fig. 10, when the straight-line distance between the transmitter 2 and the receiving tag 3 in the horizontal plane 10 becomes short and the angle θ approaches 90 degrees, there is only one intersection point, and when the straight-line distance becomes even shorter, there is no intersection point and the straight-line distance cannot be calculated, and so the accuracy of the current straight-line distance may decrease.

[0099] In such a case, the position calculation unit 52 calculates the previous relative position L Ｎ－１ , the direction vector V of the tag 3 moving from the previous time to the current time Ｎ , and the distance traveled by the receiving tag 3 from the previous time to the current time to determine the current relative position L Ｎ Therefore, even if the accuracy of the linear distance is low, the relative position L of the receiving tag 3 in the horizontal plane 10 can be measured with high accuracy. Even in this case, the moving distance and the direction vector V Ｎ Since the measurement of the relative position L using the above method is performed only under special conditions, errors are unlikely to accumulate.

[0100] (Operation Example) Fig. 11 is a flowchart showing an operation example of the hybrid positioning method 1a shown in Fig. 7. In Fig. 11, in step S1, the previous relative position L Ｎ－１ Calculating backwards from this, the straight-line distance b Ｎ－１ Next, in step S2, the previous angle θ is calculated from the following equation: Ｎ－１ Calculate θ Ｎ－１ = arctan(b Ｎ－１ , h)

[0101] Next, in step S3, the previous angle θ N-1 and the angle θ N-２ from the current angle θ Ｎ Next, in step S4, the radius of the receiving tag 3 on the horizontal plane 10 is predicted as b Ｎ That is, the circle (first position information) of angle θ Ｎ Once this is determined, the angle θ Ｎ and the distance measured this time a Ｎ Based on this, the straight-line distance b ＮSteps S1 to S4 correspond to the distance calculation step and the distance calculation unit 51. Ｎ = a Ｎ ×cos(θ Ｎ )

[0102] In the above process, the straight-line distance b calculated by the distance calculation unit 51 during the positioning before last and the previous positioning is Ｎ―２ , b Ｎ―１ " or "the relative position L calculated by the position calculation unit 52 at the time of the positioning before last and the previous time" Ｎ―２ , L Ｎ―１ Straight-line distance b calculated backward from Ｎ―２ , b Ｎ―１ Based on this, the straight-line distance b Ｎ It can be said that this is a prediction.

[0103] That is, in the above process, the relative positions L calculated by the position calculation unit 52 at the time of the positioning before last and the previous time are N-２ , L N-1 When the storage unit 55 stores the relative position L N-２ , L N-1 Straight-line distance b calculated backward from N-２ , b N-1 " based on the angle θ Ｎ By predicting the angle θ Ｎ and the distance measured this time a Ｎ Using this, the straight-line distance b Ｎ can be calculated.

[0104] In addition, the distance calculation unit 51 calculates the straight-line distance b N-２ , b N-1 When the storage unit 55 stores the calculated result of the distance b N-２ , b N-1 Based on the angle θ Ｎ By predicting the angle θ Ｎ and the distance a measured this time Ｎ Using this, the straight-line distance b Ｎ can be calculated.

[0105] Next, in step S5, the direction vector V in which the receiving tag 3 has moved is calculated based on the detection result of the geomagnetic sensor 67. Ｎ Next, in step S6, the previous relative position L Ｎ－１ From V Ｎ Next, in step S7, a virtual straight line (second position information) defined by the radius b Ｎ The intersection of the circle (first position information) and the virtual line (second position information) is calculated.

[0106] Next, in step S8, it is determined whether there are two intersections. If it is determined in step S8 that there are two intersections, the previous relative position L Ｎ－１ The receiver's current relative position L Ｎ It is determined as follows.

[0107] Next, if it is determined in step S8 that there are not two intersections, it is determined in step S10 whether there is one intersection. If it is determined in step S10 that there is one intersection, the one intersection is set to the current relative position L Ｎ It is decided that:

[0108] Next, in step S10, if it is determined that there is not one intersection, in step S12, the previous relative position L Ｎ－１ , a direction vector V calculated based on the detection result of the geomagnetic sensor 67 Ｎ , and the movement distance calculated based on the detection result of the acceleration sensor 68, the current relative position L Ｎ Steps S4 to S12 correspond to the position calculation step and the position calculation unit 52.

[0109] (Evaluation 1) Fig. 12 is an explanatory diagram showing the results of evaluation 1 of the hybrid positioning method 1a shown in Fig. 7. In evaluating the hybrid positioning method 1a, markers were placed linearly at positions on the horizontal plane 10 at linear distances of 1 m, 3 m, 5 m, 7 m, and 10 m from the transmitter 2, and the receiving tag 3 was moved linearly along the markers. Based on the reception results at the receiving tag 3, the linear distance of the receiving tag 3 on the horizontal plane 10 was calculated, and the results are shown in Fig. 12.

[0110] The upper part of Figure 12 shows a graph showing the time when the receiving tag 3 is moved linearly and the measurement results of the straight-line distance between the transmitter 2 and the receiving tag 3 in the horizontal plane 10, and the lower part of Figure 12 shows the measurement values ​​of the straight-line distance between the transmitter 2 and the receiving tag 3 in the horizontal plane 10 at the marker position.

[0111] 12, when the receiving tag 3 is moved, the straight-line distance between the transmitter 2 and the receiving tag 3 can be calculated correctly and continuously, and the standard deviation is less than 0.032 m. Therefore, it was confirmed that the hybrid positioning method 1a operates correctly.

[0112] (Evaluation 2) Fig. 13 is an explanatory diagram showing a method for evaluation 2 of the hybrid positioning method 1a shown in Fig. 7. Fig. 14 is an explanatory diagram showing the results of evaluation 2 shown in Fig. 13. Fig. 14(A) is an explanatory diagram showing the time progression of the results of measuring the distance a in space between the transmitter 2 and the receiving tag 3 in evaluation 2, and Fig. 14(B) is an explanatory diagram showing the time progression of the results of calculating the angle θ formed by the line connecting the transmitter 2 and the receiving tag 3 in space with the horizontal plane 10 in evaluation 2. Fig. 15 is an explanatory diagram showing the results of measuring the position of the receiving tag 3 on a two-dimensional coordinate system in evaluation 2.

[0113] As shown in Figure 13, a rectangular movement path 11 was set in advance within a horizontal plane 10, and the receiving tag 3 was moved along the movement path 11 while measuring the distance a in space shown in Figure 14(A) and the angle θ shown in Figure 14(B) at 0.1 second intervals, obtaining measurement results for the relative positions (movement distance in the x-axis direction and the y-axis direction) shown by black circles (●) in Figure 15. Figure 15 shows the movement path 11 shown in Figure 13 with a solid line. Figure 15 also shows the results of a reference example in which positioning was performed using a triaxial acceleration sensor and a triaxial gyro sensor with cross marks.

[0114] 14(A) and 14(B) were obtained without a filter to remove noise, and therefore noise is present, but generally stable measurement results were obtained, and positioning was possible with a maximum measurement error of 0.25 m, as shown in Fig. 15. In contrast, in the reference example using a triaxial acceleration sensor and a triaxial gyro sensor, an error of 0.8 m continued to occur due to the influence of accumulated error.

[0115] (Configuration Example 2 of Hybrid Positioning Method 1a) FIG. 16 is an explanatory diagram of Configuration Example 2 of the hybrid positioning method 1a employed in the present invention. As shown in FIG. 16, in Configuration Example 2, a mobile phone base station compatible with the fifth generation mobile communication system (5G) is used as the transmitter 2. The bandwidth used in the fifth generation mobile communication system uses the 3.6 to 6 GHz band and the higher frequency 28 GHz band in addition to the frequency band of 3.6 GHz or less that has been used in the fourth generation mobile communication system (4G), thereby enabling high speeds. Therefore, it is suitable for use in the hybrid positioning method 1a.

[0116] On the other hand, as the frequency increases, the radio waves have a disadvantage of being less likely to reach long distances, but this disadvantage is less likely to be a problem when positioning is performed indoors, etc. Conversely, since the radio waves have a harder time reaching long distances, base stations can be placed in many places, making them easier to use as transmitters 2.

[0117] (Configuration example 3 of hybrid positioning method 1a) Although not shown in the figure, a hybrid positioning method 1a may be constructed by using one of multiple portable terminals having common communication functions as a transmitter 2 and using the other portable terminals as receiving tags 3.

[0118] 17 and 18 , an example in which configuration example 4 of the hybrid positioning method 1a is used for positioning in the second space B in embodiment 1 and in the second space B in embodiment 2 will be described. Note that configuration example 4 of the hybrid positioning method 1a can also be applied to positioning in the first space A in embodiment 2.

[0119] Fig. 17 is an explanatory diagram of a configuration example 4 of the hybrid positioning method 1a employed in the present invention. Fig. 18 is a block diagram of the hybrid positioning method 1a shown in Fig. 17. As shown in Fig. 17, in the hybrid positioning method 1a of the present invention, the second space B includes a plurality of subspaces adjacent to each other in the horizontal direction. A second transmitter 2B is provided in each of the plurality of subspaces, and in the hybrid positioning method 1a, even if the receiving tag 3 moves through the plurality of subspaces, the position of the receiving tag 3 in the horizontal plane 10 is detected using radio waves from the transmitter 2B installed in the subspace in which the receiving tag 3 is determined to be currently located.

[0120] The configuration and operation of the hybrid positioning method 1a will be described below using an example of two subspaces B1 and B2 that are horizontally adjacent in the second space B. Note that this embodiment can also be applied to cases where there are three or more subspaces. For example, the present invention can also be applied to cases where another subspace is adjacent to the direction in which the subspaces B1 and B2 are lined up, or cases where another subspace is adjacent to the direction intersecting the direction in which the subspaces B1 and B2 are lined up.

[0121] 17 , in positioning system 1, second transmitter 2B is arranged as transmitter 2B1 in subspace B1 and is installed as transmitter 2B2 in subspace B2. Radio waves emitted from transmitters 2B1 and 2B2 include time information necessary for positioning, identification information with which transmitters 2B1 and 2B2 can be identified, and the like.

[0122] 18, the receiver tag 3 is provided with a radio wave designation unit 45. The radio wave designation unit 45 identifies in which subspace the receiver tag 3 is currently located based on the results of receiving radio waves from each of the multiple transmitters 2B1, 2B2, and, based on the identification result, designates the radio waves from the transmitter 2B installed in the subspace in which the receiver tag 3 is located as the radio waves to be used for positioning the receiver tag 3. The radio wave designation unit 45 may also designate the transmitters 2B1, 2B2.

[0123] For example, if, while the receiving tag 3 is moving in the subspace B1 toward the subspace B2, the radio waves from the transmitter 2B1 become unable to be demodulated while the radio waves from the transmitter 2B2 become demodulatable, if the reception strength of the radio waves from the transmitter 2B1 becomes lower than the reception strength of the radio waves from the transmitter 2B2, or if the arrival time of the radio waves from the transmitter 2B1 becomes slower than the arrival time of the radio waves from the transmitter 2B2, the radio wave designation unit 45 determines that the receiving tag 3 has moved beyond the boundary B0 into the subspace B2, and designates the radio waves from the transmitter 2B2 installed in the subspace B2 as the radio waves to be used for positioning the receiving tag 3.

[0124] Therefore, the calculation unit 50 shown in Fig. 18 switches the radio waves used for positioning from the radio waves of transmitter 2B1 to the radio waves of transmitter 2B2 and performs subsequent positioning. More specifically, when the receiving tag 3 moves through multiple sub-spaces B1 and B2, the distance calculation unit 51 shown in Fig. 18 calculates the straight-line distance b described with reference to Fig. 7 using the radio waves of the transmitter 2B that is installed in the sub-space in which the receiving tag 3 is currently located, out of the multiple sub-spaces B1 and B2.

[0125] Thus, according to configuration example 4, when the receiving tag 3 is located in subspace B1, the position of the receiving tag 3 in horizontal plane 10B1 that passes through the height position of the receiving tag 3 in subspace B1 can be measured using radio waves from transmitter 2B1, and when the receiving tag 3 is located in subspace B2, the position of the receiving tag 3 in horizontal plane 10B2 that passes through the height position of the receiving tag 3 in subspace B2 can be measured using radio waves from transmitter 2B2. Furthermore, at the boundary B0 between subspace B1 and subspace B2, it is possible to switch between the radio waves from transmitters 2B1 and 2B2 used for positioning.

[0126] Therefore, according to configuration example 4, the position of the receiving tag 3 can be measured with high accuracy over a wide range. Furthermore, even if the range of radio waves from transmitters 2B1 and 2B2 is narrow, the position of the receiving tag 3 can be measured over a wide range, so that transmitters with a radio wave reachable distance can be used as transmitters 2B1 and 2B2. For example, beacons can be used as transmitters 2B1 and 2B2.

[0127] Here, it can be assumed that the height position of the receiver tag 3 from the floor is the same in subspace B1 and subspace B2, and therefore even if the floor heights are different in subspace B1 and subspace B2, or even if the height of transmitter 2B1 from the floor of subspace B1 and the height of transmitter 2B2 from the floor of subspace B2 are different, the heights hB1 and hB2 of transmitters 2B1 and 2B2 from horizontal planes 10B1 and 10B2 passing through the height position of the receiver tag 3 can be determined in each of subspaces B1 and B2. Therefore, according to configuration example 4, it is possible to detect the relative position of the receiver tag 3 with respect to transmitter 2B1 in horizontal plane 10B1 passing through the height position of the receiver tag 3 in subspace B1, and the relative position of the receiver tag 3 with respect to transmitter 2B2 in horizontal plane 10B2 passing through the height position of the receiver tag 3 in subspace B2.

[0128] Note that subspace B1 and subspace B2 may be superimposed, and in the superimposed region, positioning may be possible using radio waves from either transmitter 2B1 or 2B2.

[0129] (Configuration Example 5 of Hybrid Positioning Method 1a) In hybrid positioning method 1a, as described with reference to Figures 7, 8, and 9, when distance calculation unit 51 calculates the straight-line distance b between transmitter 2 and receiver tag 3, it uses the height h of transmitter 2 relative to horizontal plane 10. Here, height h corresponds to the value obtained by subtracting the height of receiver tag 3 from the floor from the height of transmitter 2, and is set depending on the expected usage situation, etc. In this case, the height of transmitter 2 from the floor may vary depending on the height of the user carrying receiver tag 3, which may cause errors in the positioning results.

[0130] Therefore, it is preferable to have the user, at a point where the straight-line distance b from the transmitter 2 is known, perform an operation to instruct the user to correct the height h of the transmitter 2, thereby calculating and correcting the height h of the transmitter 2 from the radio wave reception results, and measure the position in the horizontal plane 10 corresponding to the height position of the receiver tag 3 for each user. It is also preferable to have the user input information such as their height into the receiver tag 3, thereby correcting the height h of the transmitter 2 to correspond to the height position of the receiver tag 3 for each user, and measuring the position in the horizontal plane 10 corresponding to the height position of the receiver tag 3 for each user.

[0131] (Variation of Configuration Example 5 of Hybrid Positioning Method 1a) The correction to the height h of the transmitter 2 described in Configuration Example 5 can also be applied to cases where floor heights are different within a space covered by one transmitter 2. For example, the height h of the transmitter 2 may be set in advance for each area with a different floor height within a space covered by one transmitter 2, and if it is predicted that the receiving tag 3 will move to an area with a different floor height, the height h of the transmitter 2 may be changed when the distance calculation unit 51 calculates the straight-line distance b.

[0132] [Embodiment 3] In the above embodiment, a receiver tag 3 may be mounted on a robot that moves in a warehouse, shopping center, or the like, and the robot's position may be monitored by monitoring equipment located away from the receiver tag 3. In this case, for example, the current position of the robot calculated by the receiver tag 3 is transmitted to the monitoring equipment directly or via the transmitter 2. Furthermore, of the components shown in Figures 2 and 4, at least the receiver 31, transmitter 32, communication control unit 33, and sensor 60 may be provided in the receiver tag 3, while the calculation unit 50 and the like may be provided in the monitoring equipment. In this case, data obtained by the receiver tag 3 is transmitted to the monitoring equipment directly or via the transmitter 2, and the current position of the moving device is calculated in the monitoring equipment.

[0133] [Embodiment 4] In the above embodiment, a receiving tag 3 may be attached to a package stored in a warehouse, a distribution center, etc., and the storage location of the package may be managed using a monitoring device located away from the storage location when the package is stored. For example, when packages are stored on each shelf level, by setting a horizontal plane 10 for each shelf level and setting a height h of the transmitter 2 from the horizontal plane 10 for each shelf level, the position of the package on each shelf level in two-dimensional coordinates can be accurately measured and managed.

[0134] [Other Embodiments] The present invention is not limited to the above-described embodiment, and various modifications and applications are possible within the scope of the invention as defined in the claims. For example, two transmitters 2 may be provided in the hybrid positioning system 1a shown in FIG.

[0135] According to the present invention, it is possible to provide a positioning system, a positioning method, and a receiving tag that can continue to perform proper positioning even when the receiving tag moves and stays between a first space in which the first radio wave can be demodulated and a second space in which the first radio wave cannot be demodulated.

[0136] 1 Positioning system, 1a Hybrid positioning method, 2 Transmitter, 2A First transmitter, 2B Second transmitter, 3 Receiving tag, 10 Horizontal plane, 10A First horizontal plane, 10B Second horizontal plane, 11 Movement path, 20, 30 Communication module, 21, 31 Receiving unit, 31A First receiving unit, 31B Second receiving unit, 32A First transmitting unit, 32B Second transmitting unit, 22, 32 Transmitting unit, 23, 33 Communication control unit, 33A First communication control unit, 33B Second communication control unit, 24, 34 Antenna, 35 Control unit, 36 Display unit, 50 Calculation unit, 50A First calculation unit, 50B Second calculation unit, 51 Distance calculation unit, 52 Position calculation unit, 53 Position monitoring unit, 54 Position determination unit, 55 Memory unit, 60 Sensor, 61 Inertial sensor, 62 Single board computer, 65 Data processing unit, 66 motion sensor, 67 geomagnetic sensor, 68 acceleration sensor, 69 gyro sensor, A first space, B second space, B1, B2 subspaces, C superimposed subspace B1 distance, b linear distance, θ angle, L relative position, O intersection point

Claims

1. A positioning system for measuring the position of a receiving tag moving between a first space in which a first radio wave emitted from a first transmitter can be demodulated and a second space in which the first radio wave cannot be demodulated, comprising: a second transmitter disposed in the second space and emitting a second radio wave that cannot be demodulated in the first space; a first calculation unit that performs positioning calculations to measure the position of the receiving tag in a virtual first horizontal plane set in the first space based on the reception result of the first radio wave emitted from the first transmitter at the receiving tag; a second calculation unit that performs positioning calculations to measure the position of the receiving tag in a virtual second horizontal plane set in the second space based on the reception result of the second radio wave emitted from the second transmitter at the receiving tag; and a movement detection unit that detects movement of the receiving tag between the first space and the second space based on the demodulation status of the first radio wave and the second radio wave at the receiving tag. a position determination unit that, when it is determined based on the detection result of the movement detection unit that the receiving tag is located in the first space and not in the second space, determines the position of the receiving tag based on the calculation result of the first calculation unit, and when it is determined based on the detection result of the movement detection unit that the receiving tag is located in the second space and not in the first space, determines the position of the receiving tag based on the calculation result of the second calculation unit.

2. The positioning system described in claim 1, characterized in that there is an overlapping space where the first space and the second space overlap, and when the position determination unit determines that the receiving tag is located in the overlapping space based on the detection result of the movement detection unit, it determines the position of the receiving tag based on both the calculation result of the first calculation unit and the calculation result of the second calculation unit.

3. The positioning system of claim 1 or 2, characterized in that when the position determination unit determines, based on the detection results of the movement detection unit, that the receiving tag is located in one of the first space and the second space and that the receiving tag is not located in the other space, it stops calculations in the calculation unit corresponding to the other space, out of the first calculation unit and the second calculation unit.

4. The positioning system described in claim 3, characterized in that when the position determination unit determines, based on the detection results of the movement detection unit, that the receiving tag is moving from one space to the other space, it resumes calculations in the calculation unit that had been stopped.

5. The positioning system described in claim 1 or 2, characterized in that the first space and the second space are adjacent to or partially overlap in the movement path of the receiving tag, and when the position determination unit determines that the receiving tag has entered the second space from the first space side based on the detection result of the movement detection unit, it determines the initial position of the receiving tag in the second horizontal plane based on the calculation result of the first calculation unit, and causes the second calculation unit to perform positioning calculations using the determined initial position in the second horizontal plane.

6. The positioning system described in claim 5, characterized in that when the position determination unit determines that the receiving tag has entered the first space from the second space side based on the detection result of the movement detection unit, it determines the initial position of the receiving tag in the first horizontal plane based on the calculation result of the second calculation unit, and causes the first calculation unit to perform positioning calculations using the determined initial position in the first horizontal plane.

7. A positioning system as described in claim 1 or 2, characterized in that the first transmitter is a positioning satellite located in the first space, and the second transmitter is a base station located in the second space.

8. A positioning system as described in claim 1 or 2, characterized in that the first transmitter is a base station located in the first space, and the second transmitter is a base station located in the second space.

9. The positioning system described in claim 1 or 2, characterized in that the receiving tag comprises a first receiving unit that receives and demodulates the first radio wave, a second receiving unit that receives and demodulates the second radio wave, the first calculation unit, the second calculation unit, the movement detection unit, and the position determination unit.

10. The positioning system described in claim 1 or 2, characterized in that the receiving tag is equipped with a first receiving unit that receives and demodulates the first radio wave and a second receiving unit that receives and demodulates the second radio wave, and the movement detection unit, the first calculation unit, the second calculation unit, and the position determination unit are located in a management center that is capable of wireless communication with the receiving tag.

11. A positioning method for measuring the position of a receiving tag moving between a first space in which a first radio wave emitted from a first transmitter can be demodulated and a second space in which the first radio wave cannot be demodulated, comprising: providing a second transmitter in the second space for emitting a second radio wave that cannot be demodulated in the first space; a first calculation step for performing positioning calculation to measure the position of the receiving tag in a virtual first horizontal plane set in the first space based on the reception result of the first radio wave emitted from the first transmitter at the receiving tag; a second calculation step for performing positioning calculation to measure the position of the receiving tag in a virtual second horizontal plane set in the second space based on the reception result of the second radio wave emitted from the second transmitter at the receiving tag; and a movement detection step for detecting movement of the receiving tag between the first space and the second space based on the demodulation status of the first radio wave and the second radio wave at the receiving tag. a tag position determination process for determining the position of the receiving tag based on the calculation result of the first calculation process when it is determined based on the detection result of the movement detection process that the receiving tag is located in the first space and not in the second space, and for determining the position of the receiving tag based on the calculation result of the second calculation process when it is determined based on the detection result of the movement detection process that the receiving tag is located in the second space and not in the first space.

12. A receiving tag capable of measuring its own position as it moves between a first space capable of demodulating a first radio wave emitted from a first transmitter and a second space incapable of demodulating the first radio wave, comprising: a first calculation unit that performs positioning calculations to measure the position in a virtual first horizontal plane set in the first space based on the reception result of the first radio wave emitted from the first transmitter; a second calculation unit that performs positioning calculations to measure the position in a virtual second horizontal plane set in the second space based on the reception result of a second radio wave that is emitted from a second transmitter located in the second space and cannot be demodulated in the first space; and a movement detection unit that detects the movement of the receiving tag itself between the first space and the second space based on the demodulation status of the first radio wave and the second radio wave. a position determination unit that determines the position of the receiving tag itself based on the calculation result of the first calculation unit when it is determined based on the detection result of the movement detection unit that the receiving tag itself is located in the first space and that the receiving tag itself is not located in the second space, and that determines the position of the receiving tag itself based on the calculation result of the second calculation unit when it is determined based on the detection result of the movement detection unit that the receiving tag itself is located in the second space and that the receiving tag itself is not located in the first space.

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