JP5524372B1 - Position detection system and position detection method - Google Patents

Abstract

An object of the present invention is to make it possible to efficiently grasp the position of a moving body over a wide range.
In a position detection system 1 configured using a position location system including a mobile terminal 10 provided in a mobile body 3 and a base station 20 provided in an area where the mobile body 3 moves, a base station 20 However, based on the position location signal 800 sent from the mobile terminal 10, the mobile terminal 10 has crossed any of the antenna arrangement axes of the antenna group 25 of the base station 20, and in any direction of the antenna arrangement axes. By detecting whether the vehicle has crossed, an area where the mobile body 3 (mobile terminal 10) is present is detected. Further, the number of antenna arrangement axes is increased by combining a plurality of antenna groups 25, and the area where the mobile terminal 10 exists can be specified with higher accuracy. In addition, a plurality of base stations 20 are provided in an area in which the moving body 3 moves to configure a detection zone used for handover or the like.
[Selection] Figure 5

Description

  The present invention relates to a position detection system and a position detection method, and more particularly to a technique for efficiently grasping the position of a moving body over a wide range.

  As a mechanism for grasping the position of a moving body, for example, in Non-Patent Document 1, wireless signals are transmitted from a plurality of antennas installed in a base station to a portable terminal carried by a pedestrian and transmitted from each antenna. A position detection system is disclosed in which a relative position between a portable terminal and an antenna is obtained based on a phase difference of signals, and a current position of a pedestrian is obtained from the obtained relative position (direction, distance) and an absolute position of a base station.

  Patent Document 1 relates to a technique using the position detection system described above. In a system that uses a plurality of wireless markers to determine direction, distance, position, or a combination thereof, the first wireless marker service provision area To control the handover of the second wireless marker to the service providing area.

  Further, Patent Document 2 relates to a handover method and a method thereof in a mobile communication system, and provides service providing areas in a closed space inner direction and a closed space outer direction in the vicinity of the closed space in the service providing area of the first base station. A second base station is provided, the second base station secures a first service provision area in the closed space inward direction by the first antenna, and provides a second service in the closed space outward direction by the second antenna. It is described that an area is secured.

JP 2008-199589 A Japanese Patent Laid-Open No. 2002-64847

Takenori Takeuchi, Kiminori Kono, Minoru Kono, “Development of a location detection system using the 2.4 GHz band”, The 56th Annual Conference of the Chugoku Branch of the Institute of Electrical and Information Engineering, 2005

  By the way, in the position detection system disclosed in Non-Patent Document 1, since the area covered by one base station is limited to a predetermined range, a system for grasping the current position of the position detection target over a wide range by the system. If it is going to construct | assemble, it will be necessary to install many base stations in the area which it is going to cover, and the load and cost which installation and maintenance of an installation have become a problem. In a position detection system, a directional antenna is used as a base station antenna in order to suppress the influence of indirect waves and improve the positioning accuracy. It is necessary to install a base station.

  The present invention has been made in view of such a background, and has been made for the purpose of providing a position detection system and a position detection method capable of efficiently grasping the position of a moving body over a wide range. Is.

  In order to achieve the above object, one of the present invention includes a mobile terminal that is provided in a mobile body and transmits a positioning signal that is a radio signal, and a first antenna pair and a second antenna pair. A path difference of the positioning signal received by each antenna of the first antenna pair and a path difference of the positioning signal received by each antenna of the second antenna pair having an antenna group match The first antenna pair and the second antenna pair are arranged so that the antennas of the first antenna pair and the second antenna pair are arranged in a rectangular shape on a plane, A direction in which the mobile terminal exists is obtained based on a phase difference of the positioning signals received by each antenna of the first antenna pair or each antenna of the second antenna pair, and based on the obtained direction A base station for locating the current location of the mobile terminal, and a position detection system using a location system comprising the antenna group based on the location signal sent from the mobile terminal X-axis direction plane that is a plane perpendicular to the XY plane including the X-axis that is the coordinate axis set in the direction of one side of the rectangle with the center of the rectangle as the origin, or the X-axis with the center of the rectangle as the origin The mobile terminal exists by detecting that the mobile terminal has crossed any one of the Y-axis direction planes that are perpendicular to the XY plane including the Y axis, which is the coordinate axis set in a perpendicular direction. The area to be detected is detected.

  In the positioning system having the above configuration, relatively high positioning accuracy is obtained in the vicinity of the X-axis direction plane of the antenna group and in the vicinity of the Y-axis direction plane (hereinafter referred to as the vicinity of the antenna arrangement axis). It has been found that relatively high orientation accuracy can be obtained in the vicinity of the antenna array axis even at a location away from the base station. The present invention utilizes such characteristics of the position location system, and identifies the area where the mobile terminal exists by detecting that the mobile terminal has crossed the vicinity of the antenna arrangement axis. . Advantageous Effects of Invention According to the present invention, an area where a mobile object exists can be specified even when the mobile object exists at a location away from a base station, and the range in which the position of the mobile object can be grasped by one base station Can be enlarged.

  Another aspect of the present invention is the above-described position detection system, in which the mobile terminal is directed in any direction on either the X-axis direction plane or the Y-axis direction plane of the antenna group. An area where the mobile terminal exists is detected by detecting whether the vehicle has crossed.

  In this way, the base station can be detected by detecting that the mobile terminal has crossed either the X-axis direction plane or the Y-axis direction plane (hereinafter referred to as the antenna arrangement axis) of the antenna group in any direction. It is possible to accurately grasp in which of the areas partitioned around the station the mobile terminal exists.

  Another aspect of the present invention is the above-described position detection system, wherein the base station is provided with a plurality of the antenna groups, and each of the antenna groups is made to coincide with the center of the rectangle. The coordinate axes of the antenna groups are provided so as to be shifted by a predetermined angle, and it is detected that the mobile terminal has crossed either the X-axis direction plane or the Y-axis direction plane of the antenna group. Thus, the area where the mobile terminal exists is detected.

  Thus, by combining a plurality of antenna groups and increasing the direction of the antenna arrangement axis, the position of the moving body can be grasped more accurately.

  Another aspect of the present invention is the above-described position detection system, wherein the rectangle is a square, and includes an X′Y ′ plane including an X ′ axis that is a coordinate axis set in a diagonal direction of the rectangle. A plane perpendicular to the X′-axis plane, or a Y′-axis plane which is a plane perpendicular to the X′Y ′ plane including the Y′-axis which is a coordinate axis set in the other diagonal direction of the rectangle, By further detecting that the mobile terminal has crossed any of the above, an area where the mobile terminal exists is detected.

  In the position locating system having the above-described configuration, it is possible to configure a region where relatively high locating accuracy can be obtained even in the direction of a rectangular diagonal line (X ′ axis, Y ′ axis). The present invention utilizes this, and further detects that the mobile terminal has crossed either the X ′ axis direction plane or the Y ′ axis direction plane in addition to the antenna arrangement axis described above. It is possible to accurately detect an area where a moving object exists.

  Another aspect of the present invention is the above-described position detection system, wherein the base station includes a measurement unit that measures a received electric field strength of the position determination signal, and the base station receives from the mobile terminal. When the received electric field strength of the location signal exceeds a preset threshold, the current position of the mobile terminal is calculated based on the phase difference, and the received electric field of the location signal received from the mobile terminal by the base station When the strength is equal to or less than a preset threshold, the mobile terminal detects that the mobile terminal has crossed either the X-axis direction plane or the Y-axis direction plane of the antenna group. It is assumed that an area where is present is detected.

  In this way, when the received electric field strength of the positioning signal received from the mobile terminal is strong, the current position of the mobile terminal is accurately determined based on the phase difference, and when the received electric field strength is weak, the antenna array axis of the mobile terminal is crossed. Since the position of the mobile terminal is grasped based on the information, the position locating system can be used effectively, and a mechanism for grasping the position of the moving body over a wide range can be realized with a simple configuration.

  Another one of the present invention is the position detection system, wherein the mobile terminal is provided with a plurality of the base stations in an area in which the mobile body moves, and is determined by each of the adjacent base stations. Based on the information on the area where the moving object exists, the closed area where the moving body exists is detected.

  According to the present invention, it is possible to configure a detection zone (closed region) in an area where a moving body moves. As a result, for example, a handover mechanism can be realized with a small number of base stations.

  Another one of the present invention is the position detection system described above, wherein the base station is arranged near the center of a road intersection, and any of the roads on which a vehicle equipped with the mobile terminal is connected to the road intersection. Or in which lane of the road is detected.

  According to the present invention, only one base station is arranged near the center of the road intersection, and the vehicle on which the mobile terminal is mounted is located on which road among the roads connected to the road intersection. It is possible to easily realize a mechanism for grasping whether a lane exists.

  In addition, the subject which this application discloses, and its solution method are clarified by the column of the form for inventing, and drawing.

  According to the present invention, it is possible to efficiently grasp the position of the moving body over a wide range.

1 is a diagram illustrating a schematic configuration of a position detection system 1. FIG. 2 is a diagram illustrating main hardware of a mobile terminal 10. FIG. It is a figure which shows the main functions with which the mobile terminal 10 is provided. 2 is a diagram illustrating main hardware of a base station 20. FIG. It is a figure which shows the main functions with which the base station 20 is provided. 2 is a diagram illustrating main hardware of a server device 30. FIG. It is a figure which shows the main functions with which the server apparatus 30 is provided. It is a figure which shows the data format of the location signal 800. FIG. FIG. 3 is a diagram for explaining the relationship between each antenna 251 constituting the antenna group 25 of the base station 20 and the antenna 14 included in the mobile terminal 10. FIG. 2 is a diagram for explaining a positional relationship between a base station 20 and a mobile terminal 10. It is a figure explaining the relationship between the antenna group 25 of the base station 20, the origin O, the X axis, and the Y axis. It is a figure explaining the area where comparatively high orientation accuracy is obtained. It is a figure explaining that the precision of a position location becomes high in the vicinity of an antenna arrangement axis. It is a figure explaining that the precision of a position location becomes high in the vicinity of an antenna arrangement axis. 2 is a diagram illustrating an aspect of an antenna of a base station 20. FIG. It is a flowchart explaining base station side process S1400. It is a flowchart explaining server apparatus side process S1500. 6 is an example of antenna array axis crossing information 1600; It is a figure showing an example of axis ID1613. It is an example of current position information 1800. It is an example of the detection zone comprised using the position detection system 1 of this embodiment. It is an example of the detection zone shown for a comparison. It is a figure explaining the example of application of the position detection system 1 of this embodiment.

  FIG. 1 shows a schematic configuration of a position detection system 1 described as an embodiment. The position detection system 1 is, for example, a system that manages the position of a mobile body 3 (product, transport vehicle, etc.) in a warehouse, factory, etc., a system that guides the mobile body 3 (robot, transport vehicle, etc.) in a factory, etc. A system for monitoring the current position of the body 3 (vehicle, pedestrian, etc.), a system for ensuring the safety of the mobile body 3, a system for guiding the mobile body 3 to the destination and the destination, On the other hand, the present invention is applied to a system that provides information around the current location, and a system that guides evacuation of a moving body 3 (person) in an underground shopping center or a building street.

  The position detection system 1 includes a mobile terminal 10 provided in a moving body 3 that moves in an area (hereinafter referred to as a service providing area) to which the system is applied, and a plurality of bases provided to cover the service providing area. The station 20 is configured to include a server device 30 provided in a management center of a system that manages and monitors the mobile unit 3.

  The base station 20 and the mobile terminal 10 are communicably connected to the server device 30 via a wired or wireless communication network 5 (private line, public line, Internet, etc.). When the service providing area is indoors, the base station 20 is provided, for example, on a pillar or a wall of a building. When the service providing area is outdoors, the base station 20 is provided in a structure such as a utility pole or a steel tower, for example. The base station 20 and the mobile terminal 10 are communicably connected to the server device 30 via a wired or wireless communication network 5 (private line, public line, Internet, etc.). The base station 20 performs wireless communication with the mobile terminal 10.

  FIG. 2 shows main hardware of the mobile terminal 10. As shown in the figure, the mobile terminal 10 includes a central processing unit 11 (CPU, MPU, etc.), a storage device 12 (semiconductor memory, etc.), a wireless communication interface 13, an antenna 14, an input device 15 (touch panel, operation buttons, etc.). And an output device 16 (liquid crystal display, organic EL display, speaker, etc.). These are communicably connected to each other via a bus 17.

  The antenna 14 is, for example, a directional antenna. When the service providing area is indoors, the antenna 14 is preferably a circularly polarized directional antenna. Since the plane of polarization of a circularly polarized reflected wave (or standing wave) is reversed when reflected by an obstacle such as a wall, the reflected wave or standing wave is effectively reduced by using a circularly polarized directional antenna. This is because it can be attenuated.

  FIG. 3 shows main functions of the mobile terminal 10. As shown in the figure, the mobile terminal 10 includes a position location signal transmission unit 101, an information transmission / reception unit 102, and an information display unit 103. These functions are realized by hardware included in the mobile terminal 10 or when the central processing unit 11 of the mobile terminal 10 reads and executes a program stored in the storage device 12.

  Among these, the position location signal transmission unit 101 transmits a radio signal (hereinafter referred to as a position location signal) used for position location of the mobile terminal 10 by the position location system to be described later from the wireless communication interface 13. The position location signal transmission unit 101 automatically transmits a position location signal when, for example, a preset timing (for example, every predetermined time, time registered by the user) arrives.

  The information transmitting / receiving unit 102 communicates with the base station 20 and the server device 30 through the wireless communication interface 13, transmits (uploads) various information to the base station 20 and the server device 30, and receives various information output to the output device 16 ( Download). For example, the information output unit 103 outputs information for notifying a person to the output device 16.

  FIG. 4 shows the main hardware of the base station 20. The base station 20 includes a central processing unit 21 (CPU, MPU, etc.), a storage device 22 (semiconductor memory, etc.), a communication interface 23 for connecting the base station 20 to the communication network 5, a wireless communication interface 24 for performing wireless communication, An antenna group 25, an antenna changeover switch 26, and an RSSI measurement unit 27 are provided. These components are communicably connected via a bus 28.

  The central processing unit 21 implements various functions provided in the base station 20 by reading and executing a program stored in the storage device 22. The wireless communication interface 24 receives a position location signal transmitted from the mobile terminal 10.

  The antenna group 25 includes at least four antennas 251 (directional antennas, circularly polarized directional antennas, etc.). The antenna changeover switch 26 selects any one of the antennas 251 constituting the antenna group 25 and connects it to the wireless communication interface 24. When the service providing area is indoors, the antenna 251 is preferably a circularly polarized directional antenna. Since the plane of polarization of a circularly polarized reflected wave (or standing wave) is reversed when reflected by an obstacle such as a wall, the reflected wave or standing wave is effectively reduced by using a circularly polarized directional antenna. This is because it can be attenuated.

  The RSSI measurement unit 27 measures the received signal strength indication (RSSI) of the position location signal received from the mobile terminal 10.

  FIG. 5 shows main functions of the base station 20. As shown in the figure, the base station 20 includes an information transmission / reception unit 201, a position location signal reception unit 202, an information storage unit 203, a positionable area inside / outside determination unit 204, a position location unit 205, a position location result notification unit 206, an antenna. An array axis crossing detection unit 207 and a crossing information notification unit 208 are provided. Note that these functions are realized by hardware included in the base station 20 or by the central processing unit 21 of the base station 20 reading and executing a program stored in the storage device 22.

  The information transmission / reception unit 201 controls the communication interface 23 or the wireless communication interface 24 to transmit / receive various information to / from the mobile terminal 10 or the server device 30.

  The location signal receiving unit 202 controls the wireless communication interface 24 and the antenna changeover switch 26 and receives a location signal transmitted from the mobile terminal 10.

  The information storage unit 203 stores information indicating the installation position of the base station 20 (hereinafter also referred to as installation position information). When the service providing area is indoors, the installation position information is represented by, for example, a coordinate system set indoors, a relative distance from an indoor structure (wall, pillar, etc.), and the like. When the service providing area is outdoors, the installation position information is represented by, for example, latitude / longitude or a coordinate system set to the outdoors.

  Based on the RSSI of the received position location signal, the location determination area inside / outside determination unit 204 is an area where the mobile terminal 10 that has transmitted the position location signal can currently perform position location accurately by the position location unit 205 (hereinafter referred to as the location determination area 205). , Also referred to as an area that can be determined). For example, the within-outside area determination unit 204 compares the RSSI of the received position location signal with a preset threshold (within RSSI> threshold, within the within area capable of being located, and with RSSI ≦ threshold, is within the area that can be located. Outside), it is determined whether or not the mobile terminal 10 currently exists in the location area.

  The position locating unit 205 locates the current position of the mobile terminal 10 based on the position locating signal received from the mobile terminal 10. The details of the position location mechanism by the position location unit 205 will be described later.

  The location determination result notification unit 206 transmits information indicating the current position of the mobile terminal 10 determined by the location determination unit 205 (hereinafter also referred to as a location determination result) to the server device 30.

  The antenna array axis crossing detection unit 207 detects that when the mobile terminal 10 crosses an antenna array axis described later. Details of this mechanism will be described later.

  When the antenna arrangement axis crossing detection unit 207 detects that the mobile terminal 10 has crossed the antenna arrangement axis, the crossing information notification unit 208 includes information related to this (information specifying the antenna arrangement axis traversed by the mobile terminal 10, In addition, information indicating in which direction the mobile terminal 10 has crossed the antenna array axis (hereinafter also referred to as antenna array axis crossing information) is transmitted to the server device 30.

  FIG. 6 shows the main hardware of the server device 30. As shown in the figure, the server device 30 includes a central processing unit 31 (CPU, MPU, etc.), a storage device 32 (semiconductor memory, hard disk, SSD (Solid State Drive), etc.), and an input device 33 (keyboard, mouse, etc.). A communication interface 35 that connects the output device 34 (liquid crystal display or the like) and the server device 30 to the communication network 5. These are communicably connected to each other via a bus 38. For example, information such as the current position of the moving body 3 (mobile terminal 10), the area where the moving body 3 currently exists, and the moving direction / moving speed of the moving body 3 are output to the output device 34.

  FIG. 7 shows main functions of the server device 30. As shown in the figure, the server device 30 includes an information transmission / reception unit 301, an information management unit 302, a position location result reception unit 303, a crossing information reception unit 304, and a moving object current position management unit 305. These functions are realized by hardware provided in the server device 30 or when the central processing unit 11 of the server device 30 reads out and executes a program stored in the storage device 12.

  The information transmission / reception unit 301 receives various types of information between the base station 20 and the mobile terminal 10, for example, information on the mobile 3 (mobile terminal 10) existing in the service providing area (for example, the current position of the mobile 3 and the mobile The area in which the body 3 currently exists, the moving speed, the moving direction, etc. of the moving body 3 are transmitted and received.

  The information management unit 302 manages various types of information, for example, installation position information of each base station 20.

  The location determination result receiving unit 303 receives a location determination result sent from the mobile terminal 10.

  The crossing information receiving unit 304 receives crossing information sent from the mobile terminal 10.

  The mobile body current position management unit 305 is information (hereinafter, the current position) indicating the current position of the mobile body 3 (mobile terminal 10) existing in the service providing area based on the position location result and the crossing information received from the mobile terminal 10. (Also referred to as information).

<Positioning system>
Next, the position location mechanism performed by the above-described position location system will be described. The position location system receives a position location signal, a wireless device (in this embodiment, the mobile communication interface 13 and the antenna 14 provided in the mobile terminal 10) that transmits a position location signal, which is a spread spectrum radio signal. Based on this, it is configured to include a base station (base station 20 in the present embodiment) for locating the direction and position in which the orientation target (the mobile body 3 (mobile terminal 10) in the present embodiment) exists.

  When the position is determined by the position determination system, the wireless device transmits a position determination signal. On the other hand, the base station receives a position location signal transmitted from the wireless device while periodically switching a plurality of antennas constituting the antenna group (antenna group 25 in the present embodiment).

  FIG. 8 shows the data format of the position location signal 800 transmitted from the wireless device. As shown in the figure, the position location signal 800 includes a control signal 811, a measurement signal 812, and terminal information 813.

  Among these, the control signal 811 includes a modulated wave and various control signals. The measurement signal 812 includes a non-modulated wave of about several milliseconds (for example, a signal used for detecting the direction in which the location target exists relative to the base station and the relative distance from the base station to the location target (for example, a spreading code of 2048 chips)). Is included. The terminal information 813 includes an identifier (hereinafter referred to as a terminal ID) of the wireless device that has transmitted the position location signal 800.

  FIG. 9 shows the relationship between the plurality of antennas 251 constituting the antenna group 25 of the base station 20 and the mobile terminal 10. As shown in the figure, the antenna group 25 has an interval equal to or less than one wavelength of the positioning signal 800 (for example, a wavelength λ = 12.5 cm when a 2.4 GHz band radio wave is used as the positioning signal 800). And four circularly polarized directional antennas (hereinafter referred to as antennas 251a to 251d) arranged adjacently at regular intervals in a substantially square shape in plan view. Note that each of the antennas 251a to 251d is installed, for example, with the directivity direction obliquely downward.

In the figure, if the angle formed by the horizontal direction at the height of the antenna group 25 and the direction of the mobile terminal 10 with respect to the antenna group 25 is α,
α = arcTan (D (m) / L (m)) = arcSin (ΔL (cm) / 3 (cm))
There is a relationship. Note that ΔL (cm) is a difference in propagation path length between two specific antennas 251 and the mobile terminal 10 among the antennas 251 constituting the antenna group 25 (hereinafter also referred to as a path difference). ).

Here, if the phase difference of the positioning signal 800 received by each of the two specific antennas 251 constituting the antenna group 25 is Δθ,
ΔL (cm) = Δθ / (2π / λ (cm))
There is a relationship. Further, when a 2.4 GHz band radio wave is used as the position location signal 800, λ = 12.5 (cm).
α = arcSin (Δθ / π)
There is a relationship. Since α can be calculated from Δθ (radian) within the measurable range (−π / 2 <Δθ <π / 2), the direction α in which the mobile terminal 10 is seen from the base station 20 from the above equation can be calculated. Can be acquired.

As shown in FIG. 10, the ground height of the base station 20 antenna group 25 is H (m), the ground height of the antenna 14 of the mobile terminal 10 is h (m), and the vertical line and the movement down from the antenna group 25 of the base station 20 When the orthogonal coordinate system (X, Y, Z) is set with the intersection point with the plane on which the body 3 (the mobile terminal 10) moves as the origin, the projection of the direction α onto the XZ plane is ΔΦ (X) and the direction α If the projection onto the YZ plane is ΔΦ (Y), the relative coordinates of the mobile terminal 10 with respect to the origin can be obtained from the following equation.
Δd (X) = (H−h) × Tan (ΔΦ (X))
Δd (Y) = (H−h) × Tan (ΔΦ (Y))

If the absolute coordinates of the origin are (X1, Y1, 0), the absolute coordinates (XX, YY, 0) of the mobile terminal 10 can be obtained from the following equation.
XX = X1 + Δd (X)
YY = Y1 + Δd (Y)

  Note that the basic principle of the positioning described above is disclosed in, for example, Japanese Patent Application Laid-Open Nos. 2004-184078, 2005-351877, 2005-351878, and 2006-23261. It has been detailed.

  By the way, in the position determination performed as described above, an error due to a frequency deviation generated in a crystal oscillator included in a wireless device or a base station becomes a problem. For example, when the frequency stability of the crystal oscillator is ± 0.5 ppm, a maximum frequency deviation (2400 Hz) of 1 ppm occurs between the wireless device and the base station, and the switching period of the antenna changeover switch 26 of the base station is set to 32 μs. Then, a phase difference (error) of 2400 Hz × 32 μs × 360 ° = 27.65 ° is generated. Therefore, the position locating system according to the present embodiment improves the measurement accuracy by canceling errors caused by the frequency deviation as follows.

First, the phase difference Δθ1 of the positioning signal 800 received by the first antenna pair (the first antenna 251a and the second antenna 251b) of the antenna group 25 of the base station 20 (the phase of the second antenna 251b with reference to the first antenna 251a). (= Measurement value) is obtained by measuring the propagation path of the positioning signal 800 from the antenna 14 of the mobile terminal 10 to the first antenna 251a and the positioning signal from the antenna 14 of the mobile terminal 10 to the second antenna 251b. If the true value of the phase difference caused by the difference (path difference) from 800 propagation paths is Δθt1, and the above measurement error is F1, it can be expressed by the following equation.
Δθ1 = Δθt1 + F1 Equation 1

On the other hand, the phase difference Δθ2 of the positioning signal 800 received by the second antenna pair (the third antenna 251c and the fourth antenna 251d) of the antenna group 25 of the base station 20 (with the fourth antenna 251d as a reference with respect to the third antenna 251c). As a result of measuring the phase (= measured value), the propagation path of the positioning signal 800 from the antenna 14 of the mobile terminal 10 to the third antenna 251c and the positioning from the antenna 14 of the mobile terminal 10 to the fourth antenna 251d are obtained. If the true value of the phase difference caused by the difference (path difference) from the propagation path of the signal 800 is Δθt2, and the measurement error is F2, it can be expressed by the following equation.
Δθ2 = −Δθt2 + F2 Equation 2

Further, taking the difference between both sides of Equation 1 and Equation 2, the following is obtained.
Δθ1−Δθ2 = (Δθt1 − (− Δθt2)) + (F1−F2) Equation 3

  Here, the first antenna pair and the second antenna pair are the path difference of the positioning signal 800 received by the antennas 251a and 251b of the first antenna pair and the antennas 251c and 251d of the second antenna pair. Is provided so that the path difference of the position determination signal 800 received by the signal 一致 matches, that is, the phase difference Δθt1 and the phase difference Δθt2 match, and this matching value is set as θt = Δθt1 = Δθt2. The value of (Δθt1 − (− Δθt2)) on the right side is 2θt.

On the other hand, the errors F1 and F2 are generally almost the same between the measurement of the first antenna pair and the measurement of the second antenna pair, and the value of (F1-F2) on the right side is as close to 0 as possible. Become. From the above, Equation 3 is as follows.
θt = (Δθ1-Δθ2) / 2 Formula 4

  As understood from Equation 4, the measurement errors F1 and F2 in Equations 1 and 2 can be canceled by measuring the phase difference with each of the first antenna pair and the second antenna pair. Therefore, the phase difference θt can be obtained with high accuracy by measuring the phase difference using the first antenna pair and the second antenna pair.

  For example, if the AGC (Automatic Gain Controller) is provided on the phase measurement side (base station 20 side in this embodiment) to reduce the frequency deviation, the value of (F1-F2) on the right side is Furthermore, it can approach 0, and the measurement accuracy of the phase difference θt can be further improved.

<Positioning accuracy>
By the way, the accuracy of the position determination performed by the base station 20 is not necessarily uniform in the entire area where the position can be determined, and usually the position determination accuracy is shorter as the distance between the base station 20 and the mobile terminal 10 is shorter (relative position is closer). Becomes higher. Further, the positioning accuracy is determined by the arrangement direction of the antennas 251 of the base station 20, that is, as shown in FIG. The direction of the X axis set in the direction of one side of the square with the origin O as the origin O, or the direction perpendicular to the X axis with the center of the square as the origin O (the direction of the other side adjacent to the one side) The direction of the Y axis (hereinafter, the X axis or the Y axis is also referred to as an antenna arrangement axis) set to 1 and the relative positional relationship between the antenna 14 of the mobile terminal 10 also changes.

  For example, when the antenna groups 25 of the base station 20 are arranged in a state as shown in FIG. 11A, as shown in FIG. 11B, in the vicinity of the antenna arrangement axis (a plane perpendicular to the XY plane including the X axis). It is known that relatively high orientation accuracy can be obtained when the antenna 14 of the mobile terminal 10 is present in the vicinity of (or in the vicinity of a plane perpendicular to the XY plane including the Y axis). In addition, it has been found that in the vicinity of the antenna arrangement axis, relatively high positioning accuracy can be obtained even in a predetermined range from the base station 20 near the boundary of the positionable area or outside the positionable area. Here, it can be understood, for example, that this characteristic is obtained.

  Consider a case where the antennas 251a to 251d of the base station 20 and the antenna 14 of the mobile terminal 10 are in the positional relationship shown in FIG. 12A. In the figure, the antenna 14 of the mobile terminal 10 exists in the direction of a plane perpendicular to the XY plane including the X axis. In the figure, arcs 77 and 78 indicated by alternate long and short dash lines represent the wavefronts of the positioning signal 800 transmitted from the antenna 14 of the mobile terminal 10.

  As understood from the figure, there is no difference in the arrival time of the positioning signal 800 transmitted from the antenna 14 of the mobile terminal 10 between the antenna 251b and the antenna 251c, and between the antenna 251a and the antenna 251d. However, there is no difference in the arrival time of the position location signal 800, and therefore the phase difference in the Y-axis direction is zero between the antenna 251b and the antenna 251c and between the antenna 251a and the antenna 251d.

  On the other hand, there is a difference in the arrival time of the positioning signal 800 transmitted from the antenna 14 of the mobile terminal 10 between the antenna 251a and the antenna 251b, and the positioning signal 800 of the positioning signal 800 is also between the antenna 251c and the antenna 251d. There is a difference in arrival time.

  12B is a diagram of the antenna group 25 of the base station 20 and the antenna 14 of the mobile terminal 10 as viewed from the negative direction of the Y axis when the positional relationship of FIG. 12A is present. In the figure, solid lines indicated by reference numerals 81 and 82 are position positioning signals 800 that reach the antenna group 25 of the base station 20 as direct waves among the positioning signals 800 transmitted from the antenna 14 of the mobile terminal 10, respectively. is there. In addition, broken lines indicated by reference numerals 91 and 92 reach the antenna group 25 of the base station 20 as indirect waves (multipath, reflected waves, etc.) in the positioning signal 800 transmitted from the antenna 14 of the mobile terminal 10, respectively. This is a position location signal 800. As described above, the positioning signal 800 transmitted from the antenna 14 of the mobile terminal 10 reaches the antenna group 25 of the base station 20 in a form in which the indirect wave and the direct wave are combined.

  If attention is paid to the indirect wave 91 and the indirect wave 92, there is a difference between the arrival time to the antenna 251b and the antenna 251c and the arrival time to the antenna 251a and the antenna 251d. Therefore, the influence of the indirect wave 91 on the positioning signal 800 received by the antenna 251b and the antenna 251c (the influence of the direct wave received by the antenna 251b and the antenna 251c) and the indirect wave 92 received by the antenna 251a and the antenna 251d. This is different from the influence on the position location signal 800 (influence on the direct wave received by the antenna 251a and the antenna 251d). For this reason, when an indirect wave exists, the measurement accuracy of the phase difference in the X-axis direction is affected.

  On the other hand, there is no difference in arrival time between the indirect wave 91 and the indirect wave 92 between the antenna 251b and the antenna 251c, and the position determination that the indirect wave 91 and the indirect wave 92 are received by the antenna 251b and the antenna 251c, respectively. The influence on the signal 800 (influence on the direct wave) is the same. Further, there is no difference in arrival time between the indirect wave 91 and the indirect wave 92 between the antenna 251a and the antenna 251d, and the indirect wave 91 and the indirect wave 92 are received by the antenna 251a and the antenna 251d, respectively. The effect on 800 (the effect on the direct wave) is the same. Therefore, the influence on the measurement accuracy of the phase difference in the Y-axis direction is reduced.

  It can be understood as described above that the orientation accuracy increases in the vicinity of the antenna array axis. In addition, relatively high positioning accuracy is obtained in the vicinity of the antenna arrangement axis of the base station 20 as described above, and relatively high positioning accuracy is also obtained in the predetermined range from the base station 20 near the boundary of the positionable area or outside the positionable area. Therefore, in the vicinity of the antenna arrangement axis, it is possible to detect the position of the orientation target (the direction in which the orientation target exists) for a wider range beyond the area where the orientation is possible. For this reason, when the mobile terminal 10 crosses one of the antenna arrangement axes, the base station 20 can detect this. Further, since relatively high positioning accuracy is obtained in the vicinity of the antenna arrangement axis, the base station 20 can detect in which direction the mobile terminal 10 has crossed the antenna arrangement axis. In addition, according to the above, it can be understood that relatively high orientation accuracy can be obtained in the direction in the vicinity of the antenna array axis even in a situation where only indirect waves reach.

<Antenna array axis>
By the way, for example, by combining a plurality of antenna groups 25 including the four antennas 251a to 251d arranged in the square shape shown in FIG. 11A, the antenna arrangement axes can be easily increased.

  FIG. 13 shows one mode. As shown in the figure, in this example, an antenna group 25 including four antennas 251a to 251d (hereinafter also referred to as a first antenna group) and an antenna group 25 including four antennas 251a ′ to 251d ′ ( Hereinafter, it is also referred to as a second antenna group.) By combining the center of each square of the two antenna groups 25 with the origin O, so that eight directions (+ X, + Y, -X) 45 degrees from the origin. , -Y, + X ', + Y', -X ', -Y'). Similarly, the number of antenna arrangement axes can be further increased by combining three or more antenna groups 25.

  On the other hand, two antennas located at the diagonal of the square of the antenna group 25 (in the case of the antenna group 25 shown in FIG. 11A, the antenna 251a and the antenna 251c and the antenna 251b and the antenna 215d) are combined to reduce an error caused by the frequency deviation. Even when canceling out, the antenna arrangement axes can be increased. In this case, in addition to the four directions (+ X, + Y, -X, -Y) described above, the antenna arrangement axis is a straight line connecting the antenna 251a and the antenna 251c and a straight line connecting the antenna 251b and the antenna 215d. It is also formed in the direction.

  In this case, for example, the error is canceled as follows. Here, the combination of the second antenna 251b and the fourth antenna 251d located diagonally in the antenna group 25 shown in FIG. 11A will be described as an example.

First, the phase difference Δθ1 of the positioning signal 800 received by each of the second antenna 251b and the fourth antenna 251d (the result of measuring the phase of the fourth antenna 251d with respect to the second antenna 251b (= measured value)) is the position. The true value of the phase difference caused by the difference (path difference) in the propagation path of the position location signal 800 from the antenna of the wireless device that transmits the orientation signal 800 to each antenna (the second antenna 251b and the fourth antenna 251d) is Δθt1, If the above measurement error is F1, and the influence of indirect waves (multipath, reflected wave, etc.) is α, it can be expressed by the following equation.
Δθ1 = Δθt1 + F1 + α Equation 5

On the other hand, the phase difference Δθ2 when the phase of the second antenna 251b is measured with respect to the fourth antenna 251d is determined from each antenna (the second antenna 251b and the fourth antenna 251d) from the antenna of the wireless device that transmits the positioning signal 800. If the true value of the phase difference caused by the propagation path difference (path difference) of the position location signal 800 up to is Δθt2, and the above measurement error is F2, it can be expressed by the following equation.
Δθ2 = −Δθt2 + F2-α Equation 6

Taking the difference between both sides of Equation 5 and Equation 6 gives the following.
(Δθ1−Δθ2) / 2 = ((Δθt1 + F + α) − (− Δθt2 + F−α)) / 2
= ((Δθt1 + Δθt2) + 2 · α) / 2
... Formula 7

If the second antenna 251b and the fourth antenna 251d are provided so that Δθt1 and Δθt2 are equal to each other, θt = Δθt1 = Δθt2, and (Δθt1-(− Δθt2)) on the right side of Equation 7 Is 2θt, and Equation 7 is as follows.
(Δθ1−Δθ2) / 2 = (2 · Δθt + 2 · α) / 2
= Δθt + α Equation 8

  In addition, although the influence α of the indirect wave of the indirect wave remains in the above equation, if the purpose of the positioning is limited (for example, whether Δθt = 0 or not (the mobile terminal 10 is near the antenna array axis of the base station 20) As described with reference to FIGS. 12A and 12B, the influence of indirect waves is not particularly problematic.

<The actual position detection>
By utilizing the characteristics of the positioning system that a relatively high positioning accuracy can be obtained in the vicinity of the antenna arrangement axis of the base station 20, it is possible to expand the range in which the positioning can be performed by one base station 20. Specifically, when the mobile terminal 10 exists within the area where the base station 20 can be located, the normal position is determined as described above so that the accurate position of the mobile terminal 10 can be grasped. If the mobile terminal 10 exists outside the area where it can be located, at least the area where the mobile terminal 10 currently exists can be grasped.

  14 and 15 are flowcharts for explaining this mechanism. Of these, FIG. 15 shows processing performed by the base station 20 (hereinafter this processing is referred to as base station side processing S1400), and FIG. 15 shows processing performed by the server 30 (hereinafter referred to as server device side processing S1500). .)

  As shown in FIG. 14, the base station 20 monitors in real time whether or not the position location signal 800 sent from the mobile terminal 10 moving in the service providing area is received (S1411).

  When the base station 20 receives the position location signal 800 from the mobile terminal 10 (S1411: YES), the base station 20 determines whether or not the mobile terminal 10 is present in its own location area based on the received electric field strength (S1412). ). If it is determined that the mobile terminal 10 exists in its own location area (S1412: YES), the process proceeds to S1413. If it is determined that the mobile terminal 10 does not exist in its own location area (S1412: NO), S1421. Proceed to

  In S <b> 1413, the base station 20 determines the current position of the mobile terminal 10 by performing position determination based on the received position determination signal 800, and transmits the result (position determination result) to the server device 30. Thereafter, the process returns to S1411.

  On the other hand, in S1421, the base station 20 determines whether or not the mobile terminal 10 has crossed the antenna arrangement axis. Here, as described above, the base station 20 makes this determination using the fact that relatively high location accuracy can be obtained even when the mobile terminal 10 is outside the location area in the vicinity of the antenna array axis. Note that the base station 20 repeatedly executes the base station side processing S1400 at a sufficient speed compared to the moving speed of the mobile terminal 10. Therefore, as long as sufficient positioning accuracy is obtained for the mobile terminal 10, the base station 20 can reliably determine whether or not the mobile terminal 10 has crossed the antenna arrangement axis.

  When it is determined that the mobile terminal 10 has crossed the antenna arrangement axis (S1421: YES), the base station 20 transmits the antenna arrangement axis crossing information to the server device 30 (S1422). Thereafter, the process returns to S1411.

  FIG. 16 shows an example of antenna array axis crossing information transmitted from the base station 20 to the server device 30. As shown in the figure, the antenna array axis crossing information 1600 includes information such as a terminal ID 1611, a base station ID 1612, an axis ID 1613, and a crossing direction 1614. Among these, the terminal ID 1611 is set with the terminal ID of the mobile terminal 10 (the mobile terminal 10 that has transmitted the positioning signal 800) that has crossed the antenna arrangement axis. In the base station ID 1612, an identifier (hereinafter referred to as a base station ID) assigned to the base station 20 is set. The axis ID 1613 is set with an identifier of the antenna arrangement axis traversed by the mobile terminal 10 (hereinafter referred to as axis ID). In this embodiment, it is assumed that the antenna group 25 of the base station 20 has the configuration shown in FIG. 17, and the base station 20 has “+ X”, “−X”, “+ Y”, “−Y”, “ Any of “+ X ′”, “−X ′”, “+ Y ′”, and “−Y ′” is set as the axis ID 1613 in the antenna array axis crossing information 1600.

  In the transverse direction 1614, information indicating from which direction the mobile terminal 10 has traversed the antenna arrangement axis is set. In this embodiment, for example, information such as “crossing in the direction of + X ′ to + Y ′” and “crossing in the direction of −Y to −X” is set.

  As illustrated in FIG. 15, the server device 30 determines whether or not the position location result transmitted from the base station 20 is received (S1511). When detecting that the location determination result has been received (S1511: YES), the server device 30 updates the terminal current location information of the corresponding mobile terminal 10 based on the received location determination result (S1512). Thereafter, the process proceeds to S1521.

  In S1521, the server apparatus 30 determines whether or not the antenna array axis crossing information 1600 has been received. When it is detected that the antenna arrangement axis crossing information 1600 is received from the base station 20 (S1521: YES), the server device 30 updates the current position information of the corresponding mobile terminal 10 based on the received antenna arrangement axis crossing information 1600. (S1522). Thereafter, the process returns to S1511.

  FIG. 18 shows an example of the current position information. As shown in the figure, in the current position information 1800, the current position 1812 of the mobile terminal 10 is associated with the terminal ID 1811 of the mobile terminal 10 (however, in this field, the mobile terminal 10 is present in the locable area). Only the content is set), the area 1813 where the mobile terminal 10 currently exists, the latest location determination result or the final notification base station ID 1814 that is the base station ID of the base station 20 that transmitted the antenna array axis crossing information, the current location Information such as the last update date and time 1815 of the information 1800 is included.

  As described above, the position detection system 1 according to the present embodiment can obtain relatively high positioning accuracy in the vicinity of the antenna arrangement axis of the base station 20, and can compare in the vicinity of the antenna arrangement axis even at a location away from the base station 20. An area where the moving body 3 is present is detected by utilizing the characteristic of the position locating system that a high level of locating accuracy can be obtained. For this reason, the position of the moving body 3 can be grasped over a wide range by one base station 20.

  In addition, when the mobile terminal 10 is present in the area where the base station 20 can be located, the position detection system 1 accurately grasps the position of the mobile terminal 10 by directly performing position location, and the mobile terminal 10 is outside the area where the mobile terminal 10 can be located. Since the mobile terminal 10 grasps at least the area where the mobile terminal 10 currently exists, it is possible to realize a mechanism for grasping the position of the mobile body 3 over a wide range by using the characteristics of the position location system. it can.

<Application example 1>
Based on the configuration of the position detection system 1 described above, for example, if a plurality of base stations 20 are arranged adjacent to each other in the service providing area, the current position of the mobile 3 is linked between the base stations 20. Can be implemented in real time.

  An example is shown in FIG. As shown in the figure, in this example, a plurality of base stations are installed in a lattice pattern at equal intervals in the plane of the service providing area. In the figure, the directions of the eight antenna array axes (+ X, + Y, −X, −Y, + X ′, + Y ′, −X ′, −Y ′) of each base station 20 indicate which of the adjacent base stations 20. It is made to correspond to the direction of the antenna arrangement axis. By arranging the base station 20 in such a form, a large number of detection zones (closed areas) having a right triangle shape indicated by reference numeral 191 in the figure can be easily configured in the service providing area.

  In the detection zone shown in FIG. 19, the base station 20 having four (+ X, −X, + Y, −Y) antenna arrangement axes is shown, and each antenna arrangement axis is 45 ° between adjacent base stations 20. Also by rotating the rotation (only the direction of the antenna arrangement axis between adjacent base stations 20 in the direction perpendicular to each side of the square is rotated by 45 ° between the adjacent base stations 20 in the diagonal direction of the square. The direction of the antenna array axes can be matched).

FIG. 20 is a diagram for comparison, and is an example of a detection zone based on IMES (Indoor Messaging System) or the like. As shown in the figure, in this example, the base station and the detection zone have a one-to-one correspondence. The area of each detection zone is the distance a √2 · if R π · R ^2/2 between neighboring base stations.

On the other hand, if the position detection system 1 of this embodiment, as shown in FIG. 19, the area of the distance between adjacent base stations between 20 and the √2 · R detection zone R ^2/2 (<π · R ^2/2), and when the position detecting system 1 of the present embodiment, it is possible to reduce the area of the detection zone in comparison with the case of the IMES (Indoor Messaging system) and the like. This means that the detection accuracy can be improved as compared with the conventional configuration.

  Since the distance between adjacent base stations is √2 · R in both FIG. 19 and FIG. 20, when the detection zone is configured by the position detection system 1 of the present embodiment, the conventional configuration and the base station It can be seen that even though the numbers are the same, high detection accuracy can be obtained. In other words, this means that a detection zone with the same degree of accuracy as the conventional configuration can be configured with a small number of base stations. According to the position detection system 1 of the present embodiment, a wide area can be formed with a small number of base stations. It is understood that it can be covered.

<Application example 2>
As described above, according to the position detection system 1 of the present embodiment, a single base station 20 can distinguish a plurality of areas. However, if this characteristic is used, the area around an intersection where a plurality of roads merge is used. The traffic volume can be grasped. Specifically, for example, a wireless device is provided for each vehicle that passes through an intersection. On the other hand, as shown in FIG. 21, one base station 20 is provided at a predetermined height near the center of the intersection. As a result, the presence / absence of a vehicle is ascertained for each road or lane. According to this, it is possible to easily realize a mechanism for accurately grasping the traffic volume at the intersection. In this case, if a necessary number of antenna arrangement axes are provided according to the number of roads and the number of lanes to be joined, various forms of roads can be flexibly dealt with.

  By the way, the above description is for facilitating the understanding of the present invention, and does not limit the present invention. It goes without saying that the present invention can be changed and improved without departing from the gist thereof, and that the present invention includes equivalents thereof.

  For example, in the above embodiment, the case where the antennas 251a to 251d of the antenna group 25 are arranged in a square shape has been described as an example, but the case where the antennas 251a to 251d are arranged in a rectangular shape (rectangular shape). However, a similar mechanism can be configured and a similar effect can be obtained.

  You may make it implement | achieve all or one part function of the server apparatus 30 in the mobile body 3 or the base station 20. FIG. Moreover, you may make it implement | achieve all or one part function of the base station 20 with the server apparatus 30 or the mobile body 3. FIG.

DESCRIPTION OF SYMBOLS 1 Position detection system 3 Mobile 10 Mobile terminal 20 Base station 204 Positionable area inside / outside determination unit 205 Position determination unit 206 Position determination result notification unit 207 Antenna arrangement axis crossing detection unit 208 Crossing information notification unit 30 Server device 303 Position determination result reception Section 304 Crossing information receiving section 305 Moving object current position management section

Claims (12)

A mobile terminal that is provided in the mobile body and transmits a location signal that is a radio signal;
The antenna group includes a first antenna pair and a second antenna pair, and a path difference between the positioning signals received by each antenna of the first antenna pair and each antenna of the second antenna pair And the first antenna pair and the second antenna pair are respectively connected to each of the first antenna pair and the second antenna pair. The mobile terminal is arranged so that antennas are arranged in a rectangular shape on a plane, and the mobile terminal is based on a phase difference of the positioning signal received by each antenna of the first antenna pair or each antenna of the second antenna pair. A base station for determining a direction in which the mobile terminal is located and locating a current position of the mobile terminal based on the determined direction;
A position detection system using a position locating system comprising:
A plane perpendicular to the XY plane including the X axis which is a coordinate axis set in the direction of one side of the rectangle with the center of the rectangle of the antenna group as an origin based on the position determination signal sent from the mobile terminal Either the X-axis direction plane or the Y-axis direction plane that is a plane perpendicular to the XY plane including the Y-axis that is the coordinate axis set in the direction perpendicular to the X-axis with the center of the rectangle as the origin An area in which the mobile terminal exists is detected by detecting that the mobile terminal has crossed. The position detection system according to claim 1,
An area where the mobile terminal exists is detected by detecting in which direction the X-axis direction plane or the Y-axis direction plane of the antenna group has crossed the mobile terminal. A position detection system characterized by that. The position detection system according to claim 1 or 2,
A plurality of the antenna groups are provided in the base station,
Each of the antenna groups is provided so that the centers of the rectangles coincide with each other so that the coordinate axes are shifted by a predetermined angle,
An area where the mobile terminal exists is detected by detecting that the mobile terminal crosses either the X-axis direction plane or the Y-axis direction plane of each of the antenna groups. Position detection system. The position detection system according to claim 1 or 2,
The rectangle is a square, an X ′ axial plane that is a plane perpendicular to the X′Y ′ plane including the X ′ axis that is a coordinate axis set in the diagonal direction of the rectangle, or another rectangle By further detecting that the mobile terminal has crossed any one of the Y′-axis direction planes that are perpendicular to the X′Y ′ plane including the Y′-axis that is the coordinate axis set in the diagonal direction A position detection system for detecting an area where the mobile terminal exists. The position detection system according to claim 1 or 2,
The base station includes a measurement unit that measures the received electric field strength of the position location signal,
If the received electric field strength of the positioning signal received from the mobile terminal by the base station exceeds a preset threshold, the current position of the mobile terminal is calculated based on the phase difference,
When the received electric field strength of the positioning signal received by the base station from the mobile terminal is equal to or lower than a preset threshold, either the X-axis direction plane or the Y-axis direction plane of the antenna group An area where the mobile terminal exists is detected by detecting that the mobile terminal has crossed the position detection system. The position detection system according to any one of claims 1 to 5,
A plurality of base stations are provided in an area where the mobile body moves, and a closed region where the mobile body exists is detected based on information on an area where the mobile terminal exists, which is determined by each of the adjacent base stations. A position detection system characterized by: The position detection system according to any one of claims 1 to 5,
The base station is arranged near the center of a road intersection, and on which road of the road connected to the road intersection the vehicle on which the mobile terminal is mounted is located, or on which lane of the road A position detection system characterized by detecting. A mobile terminal that is provided in the mobile body and transmits a location signal that is a radio signal;
The antenna group includes a first antenna pair and a second antenna pair, and a path difference between the positioning signals received by each antenna of the first antenna pair and each antenna of the second antenna pair And the first antenna pair and the second antenna pair are respectively connected to each of the first antenna pair and the second antenna pair. The mobile terminal is arranged so that antennas are arranged in a rectangular shape on a plane, and the mobile terminal is based on a phase difference of the positioning signal received by each antenna of the first antenna pair or each antenna of the second antenna pair. A base station for determining a direction in which the mobile terminal is located and locating a current position of the mobile terminal based on the determined direction;
A position detection method using a position location system comprising:
An XY plane including an X axis that is a coordinate axis set in the direction of one side of the rectangle with the center of the rectangle of the antenna group as an origin based on the position determination signal sent from the mobile terminal by the position location system An X-axis direction plane that is a plane perpendicular to the X-axis, or a Y-axis direction plane that is a plane perpendicular to the XY plane including the Y-axis that is a coordinate axis set in a direction perpendicular to the X-axis with the center of the rectangle as the origin, An area where the mobile terminal exists is detected by detecting that the mobile terminal has crossed any of the above. The position detection method according to claim 8,
The location system detects whether the mobile terminal has crossed the X-axis direction plane or the Y-axis direction plane of the antenna group in which direction, so that the mobile terminal A position detection method characterized by detecting an existing area. The position detection method according to claim 8 or 9,
A plurality of the antenna groups are provided in the base station,
Each of the antenna groups is provided so that the centers of the rectangles coincide with each other and the coordinate axes are shifted by a predetermined angle,
The location system detects an area where the mobile terminal exists by detecting that the mobile terminal crosses either the X-axis direction plane or the Y-axis direction plane of each of the antenna groups. A position detection method characterized by detecting. The position detection method according to claim 8 or 9,
The rectangle is a square, an X ′ axial plane that is a plane perpendicular to the X′Y ′ plane including the X ′ axis that is a coordinate axis set in the diagonal direction of the rectangle, or another rectangle By further detecting that the mobile terminal has crossed any one of the Y′-axis direction planes that are perpendicular to the X′Y ′ plane including the Y′-axis that is the coordinate axis set in the diagonal direction Detecting an area where the mobile terminal is present, a position detection method. The position detection method according to claim 8 or 9,
The base station includes a measurement unit that measures the received electric field strength of the position location signal,
The location system is
If the received electric field strength of the location signal received by the base station from the mobile terminal exceeds a preset threshold, the current position of the mobile terminal is calculated based on the phase difference,
When the received electric field strength of the positioning signal received by the base station from the mobile terminal is equal to or lower than a preset threshold, either the X-axis direction plane or the Y-axis direction plane of the antenna group An area where the mobile terminal exists is detected by detecting that the mobile terminal has crossed the position.

Images