Positioning system, positioning method, and reception tag

Abstract

A positioning system (1): comprises a transmitter (2) and a reception tag (3) that receives radio waves from the transmitter; and measures the position of the reception tag (3) relative to the transmitter (2) in a virtual horizontal plane (10) that is orthogonal to the vertical direction from the transmitter (2) and passes through the height position of the reception tag (3). The positioning system 1 comprises: a sensor (60) that detects movement of the reception tag (3); a distance calculation unit (51) that calculates, on the basis of a reception result of radio waves at the reception tag (3), the linear distance between the transmitter (2) and the reception tag (3) in the horizontal plane (10); and a position calculation unit (52) that calculates the relative position on the basis of the linear distance and the detection result of the sensor (60). Accordingly, it is possible to provide a positioning system (1), a positioning method, and a reception tag (3) capable of measuring the position of the reception tag (3) indoors or the like without requiring a large cost.

Description

Positioning system, positioning method, and receiving tag

[0001] The present invention relates to a positioning system, a positioning method, and a receiving tag that can measure the relative position of a receiving tag with respect to a transmitter.

[0002] If the location of a receiving tag can be measured even in spaces where radio waves from positioning satellites cannot be received, such as indoors, various applications are expected. For example, a shopping center could provide a guidance service to visitors. Furthermore, if the location of workers or objects moving indoors could be detected, it would be possible to digitalize indoor work and improve work efficiency. Therefore, it has been proposed to install multiple transmitters and use communication technologies such as Bluetooth between the multiple transmitters and the receiving tag. For example, a technology has been proposed that uses a terminal (receiving tag) that emits a predetermined signal and multiple nodes (transmitters) whose location information is known, and estimates the location of the terminal from the reception time difference between each node and the location information of each node.

[0003] JP 2008-128726 A

[0004] However, when a plurality of transmitters are provided as in the technique disclosed in Patent Document 1, there is a problem in that a large cost is incurred for installing the transmitters.

[0005] An object of the present invention is to provide a positioning system, a positioning method, and a receiving tag that can measure the position of a receiving tag indoors or the like without incurring a large amount of cost.

[0006] (1) The present invention is a positioning system comprising a transmitter and a receiving tag that receives radio waves from the transmitter, and that measures the relative position of the receiving tag with respect to the transmitter in a virtual horizontal plane that is perpendicular to the vertical direction from the transmitter and passes through the height position of the receiving tag, characterized in that the system comprises a sensor mounted on the receiving tag that detects the movement of the receiving tag, a distance calculation unit that calculates the straight-line distance between the transmitter and the receiving tag in the horizontal plane based on the reception results of the radio waves at the receiving tag, and a position calculation unit that calculates the relative position based on the straight-line distance and the detection results of the sensor.

[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 is performed using radio waves.

[0008] (2) In the present invention, it is preferable that the receiving tag has a geomagnetic sensor as the sensor for detecting a directional vector in the horizontal plane when the receiving tag moves, and that the position calculation unit calculates the relative position based on the straight-line distance and the directional vector.

[0009] (3) In the present invention, it is preferable that the position calculation unit further includes a memory unit that stores results calculated in the past, the receiving tag further includes an inertial sensor as the sensor, and under conditions in which the accuracy of the straight-line distance decreases, the position calculation unit calculates the current relative position using “the previous relative position stored in the memory unit,” “the directional vector when the receiving tag moved from the previous positioning to the current positioning,” and “the movement distance of the receiving tag from the previous positioning to the current positioning based on the detection result of the inertial sensor.”

[0010] (4) In the present invention, it is preferable that the receiving tag includes an acceleration sensor as the inertial sensor for detecting the movement distance.

[0011] (5) In the present invention, it is preferable that the receiving tag is equipped with an acceleration sensor and a gyro sensor as the sensors, and that when the geomagnetic sensor is unable to measure the geomagnetism or when the receiving tag is unable to demodulate the radio waves from the transmitter, the position calculation unit calculates the relative position based on the direction of movement based on the detection results of the gyro sensor and the distance of movement based on the detection results of the acceleration sensor.

[0012] (6) In the present invention, it is preferable that the receiving tag further includes an inertial sensor, such as at least one of an acceleration sensor and a gyro sensor, as the sensor, and that the position calculation unit performs correction when calculating the relative position based on the detection result of the inertial sensor.

[0013] (7) In the present invention, it is preferable that the receiving tag has a gyro sensor and an acceleration sensor as the sensors, and the position calculation unit calculates the relative position based on the detection result of the gyro sensor, the detection result of the acceleration sensor, and the straight-line distance.

[0014] (8) In the present invention, it is preferable that the present invention further includes a memory unit that stores results calculated by the position calculation unit in the past, and that under conditions in which the accuracy of the straight-line distance decreases, the position calculation unit calculates the current relative position using “the previous relative position stored in the memory unit,” “the detection result of the gyro sensor,” and “the detection result of the acceleration sensor.”

[0015] (9) In the present invention, it is preferable that the receiving tag has an inertial sensor, such as at least one of an acceleration sensor and a gyro sensor, as the sensor, and that the position calculation unit calculates the relative position based on the detection result of the inertial sensor and the straight-line distance.

[0016] (10) In the present invention, it is preferable that the position calculation unit further includes a memory unit that stores results calculated in the past, and that under conditions in which the accuracy of the straight-line distance decreases, the position calculation unit calculates the current relative position using “the previous relative position stored in the memory unit” and “the detection result of the inertial sensor.”

[0017] (11) In the present invention, it is preferable that the position calculation unit further includes a memory unit that stores results calculated in the past, and when multiple candidates are calculated as the current relative position, the position calculation unit determines the candidate closest to the previous relative position stored in the memory unit as the current relative position.

[0018] (12) In the present invention, it is preferable that the present invention further includes a memory unit that stores results previously calculated by the distance calculation unit or results previously calculated by the position calculation unit, and when performing current positioning, the position calculation unit calculates the current relative position based on a predicted current straight-line distance calculated based on one of the stored contents of the memory unit: “the straight-line distance calculated by the distance calculation unit during the positioning before last and the previous time” and “the straight-line distance calculated backward from the relative position calculated by the position calculation unit during the positioning before last and the previous time” and the direction vector when the receiving tag moved from the previous time to the current time.

[0019] (13) In the present invention, it is preferable that one transmitter is capable of measuring the position of the entire horizontal plane.

[0020] (14) In the present invention, it is preferable that the transmitters are arranged in each of a plurality of horizontally adjacent spaces, and that when the receiving tag moves through the plurality of spaces, the distance calculation unit calculates the straight-line distance using radio waves from the transmitter installed in the space in which the receiving tag is currently located among the plurality of spaces.

[0021] (15) In the present invention, the transmitter is preferably a mobile phone base station, a communication device capable of two-way communication in an ultra-wideband with the receiving tag, or a portable terminal having a communication function common to the receiving tag.

[0022] (16) In the present invention, it is preferable to measure the relative position in a space where radio waves from a positioning satellite cannot be demodulated, or indoors.

[0023] (17) In the present invention, it is preferable that the receiving tag includes the distance calculation unit and the position calculation unit in addition to the sensor.

[0024] (18) The present invention is a positioning method that uses a transmitter and a receiving tag that can communicate with the transmitter via radio waves and is equipped with a sensor that detects its own movement to measure the relative position of the receiving tag with respect to the transmitter in a virtual horizontal plane that is perpendicular to the vertical direction from the transmitter and passes through the height position of the receiving tag, and is characterized by comprising: a distance calculation step that calculates the straight-line distance between the transmitter and the receiving tag in the horizontal plane based on the reception results of the radio waves at the receiving tag; and a position calculation step that calculates the relative position based on the straight-line distance and the detection results of the sensor.

[0025] (19) The present invention is a receiving tag used in the positioning system of the present invention, characterized in that it comprises a receiving unit that receives radio waves emitted from the transmitter, a sensor that detects the movement of the receiving tag itself, a distance calculation unit that calculates the straight-line distance between the transmitter and the receiving tag itself in the horizontal plane based on the reception results of the radio waves at the receiving unit, and a position calculation unit that calculates the relative position based on the straight-line distance and the detection results of the sensor.

[0026] In the present invention, the relative position of the receiving tag in the horizontal plane relative to the transmitter is calculated based on the linear distance between the transmitter and the receiving tag calculated based on the radio wave reception results and the movement of the receiving tag detected by a sensor, so the relative position of the receiving tag can be calculated even with a small number of transmitters. Furthermore, since transmitters pre-installed for use in wireless communication can be used as they are, there is no need to install transmitters solely for positioning. Therefore, according to the present invention, it is possible to provide a positioning system, a positioning method, and a receiving tag that can measure the position of a receiving tag indoors, etc., without incurring significant costs for installing transmitters.

[0027] 10A is an explanatory diagram showing the basic concept of a positioning system 1 according to the present invention. FIG. 10B is a block diagram showing the basic configuration of a positioning system 1 according to the present invention. FIG. 10C is an explanatory diagram showing the basic concept of a positioning system 1 according to a first embodiment of the present invention. FIG. 10B is a block diagram showing the basic configuration of the positioning system 1 shown in FIG. 3. FIG. 10C is an explanatory diagram showing a positioning method in the positioning system 1 shown in FIG. 4. FIG. 10D is an explanatory diagram showing a case where the accuracy of straight-line distance decreases in the positioning system 1 shown in FIG. 3. FIG. 10C is a flowchart showing an example of operation of the positioning system 1 shown in FIG. 3. FIG. 10D is an explanatory diagram showing the results of evaluation 1 of the positioning system 1 shown in FIG. 3. FIG. 10E is an explanatory diagram showing a method for evaluation 2 of the positioning system 1 shown in FIG. 3. FIG. 10F is an explanatory diagram showing the results of evaluation 2 shown in FIG. 9, in which FIG. 10A 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. 10B 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. 10F is an explanatory diagram showing the results of measuring the relative position of the receiving tag when the positioning system 1 is evaluated using the method shown in FIG. 9. 10 is an explanatory diagram of a positioning system 1 according to an eighth embodiment of the present invention.FIG. 11 is a block diagram of a positioning system 1 according to an eighth embodiment of the present invention.FIG.

[0028] Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

[0029] (Basic Configuration) Fig. 1 is an explanatory diagram showing the basic concept of a positioning system 1 according to the present invention. Fig. 2 is a block diagram showing the basic configuration of the positioning system 1 according to the present invention.

[0030] As shown in Fig. 1, a positioning system 1 according to the present invention includes a transmitter 2 and a receiving tag 3 capable of receiving radio waves emitted from the transmitter 2, 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, or indoors, etc., and the positioning system 1 measures the position of the receiving tag 3 within a space where radio waves from positioning satellites cannot be demodulated, or indoors, etc. 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. 4.

[0031] The receiving tag 3 may be capable of transmitting radio waves in addition to receiving them. The transmitter 2 may be capable of receiving radio waves in addition to transmitting them. The transmitter 2 may be 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, or the like.

[0032] As will be described in more detail later, the positioning method of the present invention includes a distance calculation process for calculating 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 position calculation process for calculating 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.

[0033] 2, in the positioning system 1 according to the present invention, the transmitter 2 includes a receiving unit 21, a transmitting unit 22, a communication control unit 23, and an antenna 24. One transmitter 2 can cover the entire horizontal plane 10.

[0034] 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 in the radio wave reception results, 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 when the radio wave is received from the transmitter 2, and calculates the linear distance between the transmitter 2 and the receiving tag 3 in the horizontal plane 10 based on the calculation result.

[0035] 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.

[0036] The receiving tag 3 also has a storage unit 55 made up of a memory or the like that stores past calculation results and the like from the calculation unit 50, which is made up of the distance calculation unit 51 and the position calculation unit 52. The storage unit 55 may have either a single memory or multiple memories. The calculation unit 50 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.

[0037] 2 shows a configuration in which a distance calculation unit 51, a position calculation unit 52, etc. are provided in the receiving tag 3, and the distance calculation unit 51 calculates the linear distance based on the results of radio wave reception at the receiving tag 3. In this configuration, the receiving tag 3 can easily display the relative position, etc.

[0038] In addition, the distance calculation unit 51 and position calculation unit 52, etc. may be provided in a management center, etc., separate 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.

[0039] In either case, as shown in Figure 1, when the linear distance in space between the transmitter 2 and the receiving tag 3 is calculated, 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 calculate 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 1, the movement of the receiving tag 3 detected by the sensor 60 is indicated by an arrow.

[0040] Therefore, if the linear distance in the horizontal plane 10 (on two-dimensional coordinates) is calculated 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 calculated 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 calculated even if there is only one transmitter 2.

[0041] Furthermore, a wireless communication base station or the like that is installed in advance for use in wireless communication can also be used as the transmitter 2 as is, so the transmitter 2 does not need to be installed only for positioning.

[0042] Therefore, it is possible to provide a positioning system 1 that can measure the position of a receiving tag 3 in a space or indoors where radio waves from a positioning satellite cannot be received, without incurring a large cost for installing a transmitter 2.

[0043] [First Embodiment] Fig. 3 is an explanatory diagram showing the basic concept of a positioning system 1 according to a first embodiment of the present invention. Fig. 4 is a block diagram showing the basic configuration of the positioning system 1 shown in Fig. 3. Fig. 5 is an explanatory diagram showing a positioning method in the positioning system 1 shown in Fig. 4.

[0044] As shown in FIG. 3 , in a positioning system 1 according to a first embodiment of the present invention, a transmitter 2 is fixed in a space, such as indoors, where radio waves from a positioning satellite cannot be demodulated, and a receiving tag 3 moves in a space, such as indoors, where radio waves from a positioning satellite cannot be demodulated. In the positioning system 1, 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 the 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 the first embodiment, one transmitter 2 corresponds to the entire horizontal plane 10. The horizontal plane 10 is set, for example, within building information constructed using a digital twin, and the measurement result of the position of the receiving tag 3 is identified as a position within the virtual space.

[0045] Here, the transmitter 2 is a base station for a mobile phone compatible with the fifth generation mobile communication system (5G), a communication device capable of two-way communication in an ultra-wideband with the receiving tag 3, or a portable terminal having a communication function common to the receiving tag 3. Fig. 4 shows a configuration in which a communication device capable of two-way communication in an ultra-wideband with the receiving tag 3 is used as the transmitter 2.

[0046] 4, in the positioning system 1, the transmitter 2 and the receiving tag 3 each include a communication module 20, 30 made by QORVO under the product name DWM-1001-DEV. The communication modules 20, 30 include analog receivers as receiving units 21, 31, analog transmitters as transmitting units 22, 32, and controllers as communication control units 23, 33, and are capable of building a wireless network using a directional positioning reference signal (PRS).

[0047] 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 the above-mentioned programs in addition to the calculation results of the calculation unit 50.

[0048] 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 calculates the relative position of the receiving tag 3 with respect to the transmitter 2 within the horizontal plane 10 at regular time intervals 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.

[0049] 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 calculates the relative position using the travel distance and a direction vector under conditions where the accuracy of the linear distance decreases. In the first embodiment, the inertial sensor 61 is a three-axis 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 be three-axis.

[0050] In the first embodiment, the receiving tag 3 has a nine-axis motion sensor 66 as the sensor 60, which can supply data to the position calculation unit 52 via a single-board computer 62 equipped with a data processing unit 65. The nine-axis motion sensor 66 is equipped with a three-axis geomagnetic sensor 67, a three-axis acceleration sensor 68, and a three-axis gyro sensor 69. In the first embodiment, only the three-axis geomagnetic sensor 67 and the three-axis acceleration sensor 68 are used, but the three-axis gyro sensor 69 may be used as an auxiliary sensor as needed.

[0051] In the positioning system 1 configured in this manner, the position calculation unit 52 determines the current relative position based on the current straight-line distance calculated 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 calculated during the two previous and previous operations, from the contents stored in the memory unit 55, and the directional vector of movement of the receiving tag 3 from the previous time to the current time. Therefore, if the initial position of the receiving tag 3 is unknown when starting positioning, the calculation unit 50 cannot perform positioning calculation, so for example, it makes the receiving tag 3 pass a predetermined position and sets that predetermined position as the initial position.

[0052] 3 and 5, 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 distance of a straight line connecting the receiving tag 3 and the transmitter 2 in space is determined, and then the straight-line distance b between the transmitter 2 and the receiving tag 3 in the horizontal plane 10 is calculated. This straight-line distance b is defined as a circle in the horizontal plane 10. This circle has a hypotenuse with a length equivalent to the straight-line 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.

[0053] 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

[0054] 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.

[0055] 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. 5, 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.

[0056] 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:

[0057] 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 In this case, 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. 5, 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).

[0058] (Use of Travel Distance) Fig. 6 is an explanatory diagram of a case where the accuracy of the straight-line distance decreases in the positioning system 1 shown in Fig. 3. As shown in Fig. 6, 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.

[0059] 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 that the receiving tag 3 has moved from the previous time to the current time, the current relative position L Ｎ Therefore, even if the accuracy of the straight-line 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, since the measurement of the relative position L using the movement distance and the direction vector V is performed only under special conditions, accumulation of errors is unlikely to occur.

[0060] (Operation Example) Fig. 7 is a flowchart showing an operation example of the positioning system 1 shown in Fig. 3. In Fig. 7, 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)

[0061] 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 )

[0062] 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.

[0063] 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 a measured this time Ｎ Using this, the straight-line distance b Ｎ can be calculated.

[0064] 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.

[0065] 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.

[0066] 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 closest one to the current relative position L of the receiving tag 3 Ｎ It is determined as follows.

[0067] 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:

[0068] 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.

[0069] (Evaluation 1) Fig. 8 is an explanatory diagram showing the results of evaluation 1 of the positioning system 1 shown in Fig. 3. In evaluating the positioning system 1 according to the first embodiment, markers were placed linearly at positions at linear distances of 1 m, 3 m, 5 m, 7 m, and 10 m from the transmitter 2 in a horizontal plane 10, 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 in the horizontal plane 10 was calculated, and the results are shown in Fig. 8.

[0070] The upper part of Figure 8 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 8 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.

[0071] 8, when the receiving tag 3 is moved, the linear 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 positioning system 1 operates correctly.

[0072] (Evaluation 2) Fig. 9 is an explanatory diagram showing a method for evaluation 2 of the positioning system 1 shown in Fig. 3. Fig. 10 is an explanatory diagram showing the results of evaluation 2 shown in Fig. 9. Fig. 10(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. 10(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. 11 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.

[0073] As shown in Figure 9, 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 10(A) and the angle θ shown in Figure 10(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 11. Figure 11 also shows the movement path 11 shown in Figure 9 with a solid line. Figure 11 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.

[0074] 10(A) and 10(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. 11. 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.

[0075] [Embodiment 2] Fig. 12 is an explanatory diagram of a positioning system 1 according to embodiment 2 of the present invention. As shown in Fig. 12, in embodiment 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 includes 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 higher speeds. Therefore, it is suitable for use in the positioning system 1.

[0076] 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.

[0077] [Embodiment 3] In the above-mentioned embodiments 1 and 2, the receiving tag 3 may be provided with an acceleration sensor 68 and a gyro sensor 69 as the sensors 60, and the position calculation unit 52 may be configured to calculate the relative position of the receiving tag 3 based on the movement direction based on the detection result of the gyro sensor 69 and the movement distance based on the detection result of the acceleration sensor 68 when the geomagnetic sensor 67 is unable to measure the geomagnetism or when the receiving tag 3 is unable to demodulate the radio waves from the transmitter 2.

[0078] [Embodiment 4] In the above-mentioned embodiments 1 and 2, the receiving tag 3 may be provided with at least one inertial sensor 61 of an acceleration sensor 68 or a gyro sensor 69 as the sensor 60, and the position calculation unit 52 may be configured to perform corrections to reduce errors such as the tilt of the receiving tag 3 when calculating the relative position based on the detection results of the inertial sensor 61.

[0079] [Embodiment 5] In the above-described embodiments 1 and 2, the receiving tag 3 includes a geomagnetic sensor 67 and an acceleration sensor 68 as the sensor 60, but the receiving tag 3 may include an acceleration sensor 68 and a gyro sensor 69 as the sensor 60 without including the geomagnetic sensor 67. In this case, the position calculation unit 52 calculates the relative position of the receiving tag 3 with respect to the transmitter 2 based on the movement direction detected by the gyro sensor 69, the movement distance detected by the acceleration sensor 68, and the linear distance.

[0080] Furthermore, by providing a storage unit 55 that stores results previously calculated by the position calculation unit 52, under conditions where the accuracy of the straight-line distance is reduced, the position calculation unit 52 may calculate the current relative position using the previous relative position stored in the storage unit 55, the movement direction detected by the gyro sensor 69, and the movement distance detected by the acceleration sensor 68. The other configurations are the same as those of the first and second embodiments, and therefore description thereof will be omitted.

[0081] [Embodiment 6] In the above-described embodiments 1 and 2, the receiving tag 3 includes a geomagnetic sensor 67 and an acceleration sensor 68 as the sensor 60, but the receiving tag 3 may be configured to include at least one inertial sensor 61 of an acceleration sensor 68 or a gyro sensor 69 as the sensor 60 without including the geomagnetic sensor 67. In this case, the position calculation unit 52 calculates the relative position of the receiving tag 3 with respect to the transmitter 2 based on the detection result of the inertial sensor 61 (at least one of the movement direction detected by the gyro sensor 69 and the movement distance detected by the acceleration sensor 68) and the straight-line distance.

[0082] Furthermore, by providing a storage unit 55 that stores results previously calculated by the position calculation unit 52, the position calculation unit 52 may calculate the current relative position using the previous relative position stored in the storage unit 55 and the detection result of the inertial sensor 61 (at least one of the movement direction detected by the gyro sensor 69 and the movement distance detected by the acceleration sensor 68) under conditions in which the accuracy of the straight-line distance is reduced. The other configurations are the same as those of the first and second embodiments, and therefore description thereof will be omitted.

[0083] Seventh Embodiment Although not shown, the positioning system 1 may be constructed by using one of a plurality of portable terminals having a common communication function as the transmitter 2 and the other portable terminals as the receiving tags 3 .

[0084] [Eighth Embodiment] Fig. 13 is an explanatory diagram of a positioning system 1 according to an eighth embodiment of the present invention. Fig. 14 is a block diagram of the positioning system 1 according to the eighth embodiment of the present invention. As shown in Fig. 13, in the positioning system 1 according to the eighth embodiment, a transmitter 2 is provided in each of a plurality of spaces that are adjacent in the horizontal direction, and even if the receiver tag 3 moves through a plurality of spaces, the positioning system 1 detects the position of the receiver tag 3 within the horizontal plane 10 using radio waves from the transmitter 2 installed in the space in which it is determined that the receiver tag 3 is currently located.

[0085] The configuration and operation of the positioning system 1 according to the eighth embodiment will be described below using an example of two spaces A and B that are adjacent in the horizontal direction. Note that this embodiment can also be applied to cases where there are three or more spaces on one floor. For example, the present invention can also be applied to cases where another space is adjacent to the direction in which spaces A and B are lined up, or where another space is adjacent to the direction intersecting the direction in which spaces A and B are lined up.

[0086] 13, in the positioning system 1, the transmitters 2 are arranged as transmitter 2a in space A and as transmitter 2b in space B. The radio waves emitted from the transmitters 2a and 2b include time information necessary for positioning, identification information that can identify the transmitters 2a and 2b, and the like.

[0087] 14, the receiver tag 3 is provided with a radio wave designation unit 45. The radio wave designation unit 45 identifies in which space the receiver tag 3 is currently located based on the results of receiving radio waves from each of the multiple transmitters 2a, 2b, and, based on the identification result, designates the radio waves from the transmitter 2 installed in the space 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 transmitter 2.

[0088] For example, if, while the receiving tag 3 is moving in space A toward space B, the radio waves from transmitter 2a become unable to be demodulated while the radio waves from transmitter 2b become demodulatable, if the reception strength of the radio waves from transmitter 2a becomes lower than the reception strength of the radio waves from transmitter 2b, or if the arrival time of the radio waves from transmitter 2a becomes slower than the arrival time of the radio waves from transmitter 2b, the radio wave designation unit 45 determines that the receiving tag 3 has moved across boundary AB into space B, and designates the radio waves from transmitter 2b installed in space B as the radio waves to be used for positioning the receiving tag 3.

[0089] Therefore, the calculation unit 50 shown in Fig. 14 switches the radio waves used for positioning from the radio waves of the transmitter 2a to the radio waves of the transmitter 2b and performs subsequent positioning. More specifically, when the receiving tag 3 moves through multiple spaces A and B, the distance calculation unit 51 shown in Fig. 14 calculates the straight-line distance b described with reference to Fig. 3 using the radio waves of the transmitter 2 installed in the space where the receiving tag 3 is currently located, out of the multiple spaces A and B.

[0090] Thus, according to the eighth embodiment, when the receiving tag 3 is located in space A, the radio waves from the transmitter 2a can be used to measure the position of the receiving tag 3 in space A within the horizontal plane 10a that passes through the height position of the receiving tag 3, and when the receiving tag 3 is located in space B, the radio waves from the transmitter 2b can be used to measure the position of the receiving tag 3 in space B within the horizontal plane 10b that passes through the height position of the receiving tag 3. Furthermore, at the boundary AB between spaces A and B, it is possible to switch between the radio waves from the transmitters 2a and 2b used for positioning.

[0091] Therefore, according to the eighth embodiment, the position of the receiving tag 3 can be measured with high accuracy over a wide range. Furthermore, even if the range of the radio waves from the transmitter 2 is narrow, the position of the receiving tag 3 can be measured over a wide range, so that it is possible to use transmitters 2a and 2b whose radio waves have a relatively short range. For example, beacons can be used as the transmitters 2a and 2b.

[0092] Here, it can be assumed that the height position of the receiver tag 3 from the floor is the same in space A and space B, and therefore even if the floor heights are different in space A and space B, or even if the height of transmitter 2a from the floor of space A is different from the height of transmitter 2b from the floor of space B, the heights ha and hb of transmitters 2a and 2b from horizontal planes 10a and 10b passing through the height position of the receiver tag 3 can be determined in each of spaces A and B. Therefore, the positioning system 1 can detect the relative position of the receiver tag 3 with respect to transmitter 2a in horizontal plane 10a passing through the height position of the receiver tag 3 in space A, and the relative position of the receiver tag 3 with respect to transmitter 2b in horizontal plane 10b passing through the height position of the receiver tag 3 in space B.

[0093] It is also possible to overlap the space A and the space B, and in the overlapping space, positioning can be performed using either the radio waves from the transmitters 2a and 2b.

[0094] 3, 4, and 5, in the above embodiment, when the distance calculation unit 51 calculates the linear distance b between the transmitter 2 and the receiver tag 3, it uses the height h of the transmitter 2 relative to the horizontal plane 10. Here, the height h corresponds to the value obtained by subtracting the height of the receiver tag 3 from the floor from the height of the transmitter 2 from the floor, and is set according to the expected usage situation, etc. In this case, the height of the transmitter 2 from the floor may vary depending on the height of the user carrying the receiver tag 3, which may cause an error.

[0095] Therefore, it is preferable to have the user, at a point on each floor where the linear 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.

[0096] [Variation of the Ninth Embodiment] The correction to the height h of the transmitter 2 described in the ninth embodiment 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 receiver 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 linear distance b.

[0097] [Embodiment 10] In the above embodiments, a receiver tag 3 may be mounted on a mobile device such as a self-propelled vacuum cleaner that moves on the floor in a shopping center, office, home, etc., or a robot that moves in a distribution center, shopping center, etc., and the position of the mobile device in two-dimensional coordinates may be monitored by a monitoring device located away from the receiver tag 3. In this case, for example, the current position of the mobile device calculated by the receiver tag 3 is transmitted to the monitoring device directly or via the transmitter 2. Furthermore, of the components shown in Figure 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 device. In this case, data obtained by the receiver tag 3 is transmitted to the monitoring device directly or via the transmitter 2, and the current position of the mobile device is calculated by the monitoring device.

[0098] [Embodiment 11] In the above embodiments, 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.

[0099] [Other Embodiments] The present invention is not limited to the above-described embodiments, and it goes without saying that various modifications and applications are possible within the scope of the invention as defined in the claims.

[0100] The positioning system of the present invention can calculate the relative position of a receiving tag even with a small number of transmitters, so it can measure the position and movement of a receiving tag within a shopping center or business premises without incurring the significant cost of installing transmitters.

[0101] 1 Positioning system, 2 Transmitter, 3 Receiving tag, 10 Horizontal plane, 11 Movement path, 20, 30 Communication module, 21, 31 Receiving unit, 22, 32 Transmitting unit, 23, 33 Communication control unit, 24, 34 Antenna, 35 Control unit, 36 Display unit, 45 Radio wave designation unit, 51 Distance calculation unit, 52 Position calculation 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 Distance, b Straight-line distance, θ Angle, L Relative position, O Intersection

Claims

1. A positioning system comprising a transmitter and a receiving tag that receives radio waves from the transmitter, and that measures the relative position of the receiving tag with respect to the transmitter in an imaginary horizontal plane that is perpendicular to the vertical direction from the transmitter and passes through the height position of the receiving tag, characterized in that the positioning system comprises: a sensor mounted on the receiving tag that detects the movement of the receiving tag; a distance calculation unit that calculates the straight-line distance between the transmitter and the receiving tag in the horizontal plane based on the reception results of the radio waves at the receiving tag; and a position calculation unit that calculates the relative position based on the straight-line distance and the detection results of the sensor.

2. The positioning system described in claim 1, characterized in that the receiving tag is equipped with a geomagnetic sensor as the sensor for detecting a directional vector in the horizontal plane when the receiving tag moves, and the position calculation unit calculates the relative position based on the straight-line distance and the directional vector.

3. The positioning system of claim 2, further comprising a memory unit that stores results calculated by the position calculation unit in the past, wherein the receiving tag further comprises an inertial sensor as the sensor, and wherein, under conditions in which the accuracy of the straight-line distance decreases, the position calculation unit calculates the current relative position using "the previous relative position stored in the memory unit," "the directional vector of the receiving tag when it moved from the previous positioning to the current positioning," and "the distance traveled by the receiving tag from the previous positioning to the current positioning based on the detection result of the inertial sensor." 4. The positioning system according to claim 3, wherein the receiving tag is provided with an acceleration sensor as the inertial sensor for detecting the distance traveled.

5. The positioning system of claim 2, wherein the receiving tag is equipped with an acceleration sensor and a gyro sensor as the sensors, and the position calculation unit calculates the relative position based on the direction of movement based on the detection results of the gyro sensor and the distance of movement based on the detection results of the acceleration sensor when the geomagnetic sensor is unable to measure the geomagnetism or when the receiving tag is unable to demodulate the radio waves from the transmitter.

6. The positioning system described in claim 2, characterized in that the receiving tag is equipped with at least one inertial sensor of an acceleration sensor or a gyro sensor as the sensor, and the position calculation unit makes corrections based on the detection results of the inertial sensor when calculating the relative position.

7. The positioning system described in claim 1, characterized in that the receiving tag is equipped with a gyro sensor and an acceleration sensor as the sensors, and the position calculation unit calculates the relative position based on the detection results of the gyro sensor, the detection results of the acceleration sensor, and the straight-line distance.

8. The positioning system of claim 7, further comprising a memory unit that stores results previously calculated by the position calculation unit, wherein under conditions where the accuracy of the straight-line distance is reduced, the position calculation unit calculates the current relative position using "the previous relative position stored in the memory unit," "the detection result of the gyro sensor," and "the detection result of the acceleration sensor." 9. The positioning system described in claim 1, characterized in that the receiving tag is equipped with at least one inertial sensor of an acceleration sensor or a gyro sensor as the sensor, and the position calculation unit calculates the relative position based on the detection result of the inertial sensor and the straight-line distance.

10. The positioning system of claim 9, further comprising a memory unit that stores results previously calculated by the position calculation unit, wherein under conditions where the accuracy of the straight-line distance decreases, the position calculation unit calculates the current relative position using "the previous relative position stored in the memory unit" and "the detection result of the inertial sensor." 11. A positioning system as described in claim 1, 2, 7 or 9, further comprising a memory unit for storing results calculated by the position calculation unit in the past, wherein when multiple candidates are calculated as the current relative position, the position calculation unit determines the candidate from among the multiple candidates that is closest to the previous relative position stored in the memory unit as the current relative position.

12. A positioning system as described in claim 1, 2, 7 or 9, further comprising a memory unit for storing results previously calculated by the distance calculation unit or results previously calculated by the position calculation unit, wherein when performing current positioning, the position calculation unit uses the current straight-line distance calculated based on one of the following straight-line distances from the contents stored in the memory unit: "the straight-line distance calculated by the distance calculation unit during the positioning before last and the previous time" and "the straight-line distance calculated backward from the relative position calculated by the position calculation unit during the positioning before last and the previous time." 13. The positioning system according to claim 1, wherein a single transmitter is capable of measuring the position of the entire horizontal plane.

14. The positioning system described in claim 1, characterized in that the transmitters are arranged in each of a plurality of horizontally adjacent spaces, and the distance calculation unit calculates the straight-line distance when the receiving tag moves through the plurality of spaces using radio waves from the transmitter installed in the space in which the receiving tag is currently located.

15. The positioning system described in claim 1, characterized in that the transmitter is a mobile phone base station, a communication device capable of two-way communication in ultra-wideband with the receiving tag, or a portable terminal having communication functions common to the receiving tag.

16. The positioning system according to claim 1, wherein the relative position is measured in a space or indoors where radio waves from a positioning satellite cannot be demodulated.

17. The positioning system according to claim 1, wherein the receiving tag comprises, in addition to the sensor, the distance calculation unit and the position calculation unit.

18. A positioning method that uses a transmitter and a receiving tag that can communicate with the transmitter via radio waves and is equipped with a sensor that detects its own movement to measure the relative position of the receiving tag with respect to the transmitter in an imaginary horizontal plane that is perpendicular to the vertical direction from the transmitter and passes through the height position of the receiving tag, the positioning method comprising: a distance calculation step that calculates the straight-line distance between the transmitter and the receiving tag in the horizontal plane based on the radio wave reception results at the receiving tag; and a position calculation step that calculates the relative position based on the straight-line distance and the detection results of the sensor.

19. A receiving tag for use in the positioning system described in claim 1, comprising: a receiving unit that receives radio waves emitted from the transmitter; a sensor that detects the movement of the receiving tag itself; a distance calculation unit that calculates the straight-line distance between the transmitter and the receiving tag itself in the horizontal plane based on the reception results of the radio waves at the receiving unit; and a position calculation unit that calculates the relative position based on the straight-line distance and the detection results of the sensor.

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