JP2013195214A - Control method of position locating system, and position locating system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To adequately perform handover between base stations in a position locating system.SOLUTION: In a position locating system, a mobile terminal 30 transmits a position locating signal 1200, and a base station 20 acquires a direction ΔΦ, in which the mobile terminal 30 exists when viewed from the base station 20, on the basis of a phase difference Δθ of the position locating signal 1200 received by an antenna 25 respectively, and performs position locating of the mobile terminal 30 on the basis of the obtained direction ΔΦ. In the position locating system, a server device 10 communicably connected to each of the base stations 20 receives multipath evaluation information 600 from the base stations 20, that is information indicating a degree of multipath influence of the position locating signal 1200 received from the mobile terminal 30, and selects the base station 20 having the least degree of multipath influence on the basis of the received multipath evaluation information 600. The selected base station 20 and the other base stations 20 are controlled in a manner that position locating of the mobile terminal 30 is performed according to the selected base station 20.

Description

  The present invention relates to a method for controlling a position location system and a position location system, and more particularly to a technique for appropriately performing handover between base stations.

  In Patent Document 1, in a system for determining the direction, distance, position, etc. of a mobile terminal using a plurality of wireless markers, the result of determining the distance from the first wireless marker and the second wireless marker to the mobile terminal Based on the above, it is described that the handover from the service area of the first wireless marker to the service area of the second wireless marker is controlled.

  Non-Patent Document 1 discloses that a radio signal is transmitted from a plurality of antennas installed in a base station to a pedestrian's mobile terminal, and the relative position between the mobile terminal and the antenna is based on the phase difference of the radio signal transmitted from each antenna. A position locating system that obtains the current position of a pedestrian from the obtained relative position (direction, distance) and the absolute position of the base station is disclosed.

JP 2008-199589 A

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

  The positioning system disclosed in Patent Document 1 or Non-Patent Document 1 transmits and receives a positioning signal, which is a radio signal used for positioning, as a direct wave between a base station and a mobile terminal (portable terminal). Thus, it is possible to achieve a highly accurate location of the current position of the mobile terminal. For this reason, at the time of handover, it is necessary to appropriately select a base station used for position location in consideration of the influence of multipath.

  Here, as a method for realizing handover, in addition to the method disclosed in Patent Document 1, a method of selecting a base station having a large received electric field strength of a positioning signal is also conceivable, but the influence of multipath and reflected waves is large. In the environment, the received electric field strength may not decrease sufficiently even though the mobile terminal exists in a position where the direct wave does not reach from a certain base station. In such a case, the positioning signal is transmitted as a direct wave. Alternatively, a base station that cannot be received may be selected, and the accuracy of position location may be reduced.

  The present invention has been made in view of such a background, and an object of the present invention is to provide a control method of a position location system and a position location system capable of appropriately performing handover between base stations.

  One aspect of the present invention for achieving the above object includes a mobile terminal and a plurality of base stations having a plurality of antennas arranged adjacent to each other, and the mobile terminal determines the location of the mobile terminal. The base station transmits a location signal that is a radio signal to be used, and the base station determines a direction ΔΦ in which the mobile terminal exists from the base station based on the phase difference Δθ of the location signal received by each of the antennas. A method for controlling a location system that obtains and determines the location of the mobile terminal based on the obtained direction ΔΦ, comprising a server device communicably connected to each of the plurality of base stations, Receiving multipath evaluation information, which is information indicating the degree of multipath influence of the position location signal received from the mobile terminal, from the base station, and based on the received multipath evaluation information. Degree of influence-path selects the least the base station, and controlling the base stations and other such base station as position location of the mobile terminal is performed by the base station selected.

  According to the present invention, the server device transmits the multipath based on the multipath evaluation information, which is information indicating the degree of multipath influence of the positioning signals received from the mobile terminals, transmitted from each of the base stations. Handover is performed by selecting the base station that has the least influence (controls the base station and other base stations so that the mobile terminal is located by the selected base station), so consider the effects of multipath Thus, handover between base stations can be performed appropriately. This also ensures the accuracy of the position location.

  Another aspect of the present invention is a method of controlling the position location system, wherein the base station receives a first antenna pair and a second antenna pair by each antenna of the first antenna pair. Provided so that a path difference between the position location signals received by each antenna of the second antenna pair matches a path difference between the position location signals received by each antenna of the second antenna pair. Obtaining the direction in which the mobile terminal is present based on the phase difference Δθ of the positioning signal received by each antenna or each antenna of the second antenna pair, obtaining the position of the mobile body based on the obtained direction, The phase difference Δθ1 of the positioning signal received by each antenna of the first antenna pair is measured, and the phase difference Δ of the positioning signal received by each antenna of the second antenna pair θ2 is measured, and based on the phase difference Δθ1 and the phase difference Δθ2, the multipath influence degree of the position location signal is obtained, and the obtained multipath influence degree is obtained as the multipath evaluation information in the server apparatus. I will send it.

  According to the present invention, based on the phase difference Δθ1 of the positioning signals received by each antenna of the first antenna pair and the phase difference Δθ2 of the positioning signals received by each antenna of the second antenna pair, It is possible to easily acquire the correct degree of influence of the multipath of the position location signal sent from the mobile terminal.

  Another aspect of the present invention is a control method of the above positioning system, wherein a base station receives a first antenna pair and a second antenna pair by each antenna of the first antenna pair. Provided that the path difference of the positioning signal and the path difference of the positioning signal received by each antenna of the second antenna pair coincide with each other, and the base station provides each of the first antenna pair Obtaining the direction in which the mobile terminal exists based on the phase difference Δθ of the position location signal received by each antenna of the antenna or the second antenna pair, obtaining the position of the mobile body based on the obtained direction, The base station measures the phase difference Δθ1 of the positioning signals received by the respective antennas of the first antenna pair, and the positioning signals received by the respective antennas of the second antenna pair. The base station is provided with a number of antennas that can form a plurality of patterns of antenna groups including the first antenna pair and the second antenna pair, and the base station is provided with respect to each of the patterns. Based on the measured phase difference Δθ1 and the phase difference Δθ2, the degree of influence of each multipath of the pattern is obtained, and the variation in the degree of influence of the obtained multipath of the pattern is used as the multipath evaluation information. The data is transmitted to the server device.

  According to the present invention, it is possible to easily acquire an accurate influence level of a multipath of a position location signal transmitted from a mobile terminal based on variation in the influence degree of each multipath of a pattern.

  Another aspect of the present invention is a control method of the position location system, wherein the base station determines the position of the mobile terminal, and the measurement result of the phase difference Δθ2 corresponds to the measurement result of the phase difference Δθ1. The phase difference Δθ1 and the phase difference Δθ2 are measured using a measurement standard whose sign is inverted, and the phase difference Δθ1 is canceled in order to cancel the errors included in the measured phase difference Δθ1 and the phase difference Δθ2. And the phase difference Δθ2 is obtained by calculating the difference between the multipath of the positioning signal received from the mobile terminal and the sign of the measurement result of the phase difference Δθ2 and the measurement result of the phase difference Δθ1. Are obtained as a difference between the phase difference Δθ1 and the phase difference Δθ2 measured by measuring the phase difference Δθ1 and the phase difference Δθ2.

  According to the present invention, it is possible to determine the exact position of the mobile terminal based on the difference between the phase difference Δθ1 and the phase difference Δθ2. In addition, based on the difference between the phase difference Δθ1 and the phase difference Δθ2, it is possible to easily acquire the accurate influence degree of the multipath of the position location signal transmitted from the mobile terminal.

  Another aspect of the present invention is a control method of the position location system, wherein the base station determines the position of the mobile terminal, and the measurement result of the phase difference Δθ2 corresponds to the measurement result of the phase difference Δθ1. The phase difference Δθ1 and the phase difference Δθ2 are measured using a measurement standard whose sign is inverted, and the phase difference Δθ1 is canceled in order to cancel the errors included in the measured phase difference Δθ1 and the phase difference Δθ2. And obtaining the difference between the phase difference Δθ2 and the multipath influence degree of the positioning signal received from the mobile terminal as the sum of the measured phase difference Δθ1 and the phase difference Δθ2. And

  According to the present invention, it is possible to determine the exact position of the mobile terminal based on the difference between the phase difference Δθ1 and the phase difference Δθ2. In addition, based on the sum of the phase difference Δθ1 and the phase difference Δθ2, it is possible to easily acquire the accurate influence degree of the multipath of the position location signal transmitted from the mobile terminal.

  Another aspect of the present invention is a control method of the position location system, wherein each of the base stations is information indicating the degree of multipath influence for each coordinate axis direction component of the position location signal received from the mobile terminal. The multipath evaluation information is generated and transmitted to the server device, and the server device receives the multipath evaluation information transmitted from each of the base stations, and receives the received multipath evaluation information. The base station having the least multipath influence degree is selected for each coordinate axis direction component, and the base station is positioned by the base station individually selected for each coordinate axis direction component. It is assumed that the station and other base stations are controlled.

  Since the degree of influence of multipath usually differs for each coordinate axis (for example, the X axis and the Y axis in the orthogonal coordinates (X, Y)), the base station individually selected for each coordinate axis direction component as in the present invention, By controlling the base station and other base stations so that position location is performed, it is possible to improve the location accuracy.

  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, handover between base stations can be appropriately performed in a position location system.

1 is a diagram showing a schematic configuration of a position location system 1. FIG. 2 is a diagram illustrating main hardware of a server device 10. FIG. 3 is a diagram illustrating main functions of the server device 10. FIG. 3 is an example of base station position information 400; 4 is an example of base station charge status information 500; It is an example of the multipath evaluation information 600. 2 is a diagram illustrating main hardware of a mobile terminal 30. FIG. 2 is a diagram illustrating main functions of a mobile terminal 30. FIG. 2 is a diagram illustrating main hardware of a base station 20. FIG. 2 is a diagram illustrating main functions of a base station 20. FIG. It is an example of charge terminal information 1100. It is a figure explaining the structure of the position location signal 1200. FIG. FIG. 2 is a diagram showing a positional relationship between a base station 20 and a mobile terminal 30. FIG. 2 is a diagram illustrating the configuration of an antenna 25 of a base station 20. It is a figure explaining the positional relationship of the base station 20 and the mobile terminal 30. FIG. It is a flowchart explaining a handover process (server apparatus) S1600. It is a flowchart explaining a handover process (base station) S1700. 6 is a configuration example of a multipath evaluation information acquisition unit 107. 2 is an example of a method for realizing a pattern of an antenna group 25. FIG.

  FIG. 1 shows a schematic configuration of a position location system 1 described as an embodiment. The position location system 1 is, for example, a system that monitors the current position of a moving body 3 (people (pedestrians, etc.), vehicles, luggage, cargo, etc.), a system related to ensuring safety of the moving bodies 3 (people, vehicles, etc.), A system that provides guidance to the body 3 (people, vehicles, etc.) and guidance to the destination, a system that provides information around the current location to the mobile body 3 (people, vehicles, etc.), and evacuation in underground and building districts The present invention can be widely applied to a guidance system, a system for managing the flow of luggage or cargo in a warehouse or a factory, and a guidance system for a robot or an automatic transport vehicle in a factory.

  The location system 1 includes a server device 10 provided in a management center, a monitoring center, and the like of the location system 1, a plurality of base stations 20 provided in various locations in the area to which the location system 1 is applied, and a mobile body 3. It includes one or more mobile terminals 30 that are carried or attached.

  The base station 20 is provided at a predetermined height position from the plane on which the moving body 3 moves. For example, when the location system 1 is used indoors, the base station 20 is provided on a pillar or a wall of a building, for example. Further, for example, when the position location system 1 is used outdoors, the base station 20 is provided, for example, on a utility pole or a steel tower.

  The base station 20 and the mobile terminal 30 communicate with the server device 10 via the communication network 5. The communication network 5 is a wired or wireless communication means such as a dedicated line, a public line, a LAN (Local Area Network), a WAN (Wide Area Network), and the Internet.

  FIG. 2 shows the main hardware of the server device 10. As shown in the figure, the server device 10 includes a central processing unit 11 (CPU, MPU, etc.), a storage device 12 (semiconductor memory (RAM, ROM, NVRAM, etc.), a hard disk device, etc.), and an input device 13 (keyboard and mouse). ), A display device 14 (liquid crystal display, etc.), a communication interface 15 (NIC (Network Interface Card), wireless communication module, etc.) for connecting the server device 10 to the communication network 5 and the like. On the display device 14, for example, information indicating the current position and moving direction of the moving body 3 is displayed in real time. As shown in the figure, each component of the server device 10 is connected to be communicable with each other via a bus 18.

  FIG. 3 shows main functions of the server device 10. As shown in the figure, the server device 10 includes an information collection unit 101, an information provision unit 102, a setting information storage unit 103, a handover control unit 104, a base station location information management unit 105, a base station charge situation management unit 106, and A multipath evaluation information acquisition unit 107 is provided. These functions are realized by hardware included in the server device 10 or when the central processing unit 11 of the server device 10 reads and executes a program stored in the storage device 12.

  The information collection unit 101 receives and manages information such as the current position of the mobile terminal 30 that is sent from the base station 20 or the mobile terminal 30 as needed.

  For example, the information providing unit 102 may monitor the base station 20 or the mobile terminal 30 with monitoring information such as the current position and moving direction of the moving body 3, information about ensuring the safety of the moving body 3, route guidance information, Provide information such as guidance information and geographic information around the current location as needed.

  The setting information storage unit 103 stores, for example, information (latitude, longitude, installation height, etc.) indicating the position where the base station 20 is installed as setting information.

  The handover control unit 104 performs control related to handover of the mobile terminal 30 (assignment of a base station 20 in charge of position location described later for the mobile terminal 30).

  The base station location information management unit 105 manages (stores) information indicating the location of each base station 20 (hereinafter referred to as base station location information). The base station position information is used when a base station 20 that is a candidate for a handover destination of the target mobile terminal is selected. The base station position information is represented using, for example, two-dimensional coordinates such as XY coordinates and latitude / longitude.

  FIG. 4 shows an example of base station position information. As shown in the figure, the base station position information 400 is composed of a plurality of records including items of a base station ID 411, an X coordinate 412 and a Y coordinate 412. Of these, the base station ID 411 is set with a base station ID that is an identifier of the base station 20. In the X coordinate 412, an X coordinate indicating the position where the base station 20 is provided is set with reference to the origin provided at a predetermined position. In the Y coordinate 413, the Y coordinate indicating the position where the base station 20 is provided with respect to the origin is set.

  The base station charge status management unit 106 manages (stores) information (hereinafter referred to as base station charge status information) indicating the mobile terminal 10 in which each base station 20 is currently in charge of position location described later.

  FIG. 5 shows an example of base station charge status information. As shown in the figure, the base station charge status information 500 includes a plurality of records including items of a terminal ID 511 and a base station ID 512. Among these, a terminal ID that is an identifier of the mobile terminal 30 is set as the terminal ID 511. The base station ID 512 is set with the base station ID of the base station 20 that is currently in charge of the location determination of the mobile terminal 30 to be described later.

  The multipath evaluation information acquisition unit 107 acquires and stores multipath evaluation information, which will be described later, from the base station 20 used when the handover control unit 104 performs control related to the handover of the mobile terminal 30.

  FIG. 6 shows an example of multipath evaluation information. As shown in the figure, the multipath evaluation information 600 is composed of one or more records including items of a base station ID 611, a terminal ID 612, and multipath evaluation information 613. Among these, base station ID is set to base station ID611. In the terminal ID 612, the terminal ID of the mobile terminal 30 is set. In the multipath evaluation information 613, multipath evaluation information acquired (received) from the base station 20 for the mobile terminal 30 is set.

  FIG. 7 shows main hardware of the mobile terminal 30. As shown in the figure, the mobile terminal 30 includes a central processing unit 31 (CPU, MPU, etc.), a storage device 32 (semiconductor memory (RAM, ROM, NVRAM, etc.), a hard disk device, etc.), and a position location signal 1200 described later. Wireless communication interface 33 (NIC, wireless communication module, etc.) that performs transmission and wireless communication with other devices, antenna 34 used for wireless communication performed by wireless communication interface 33, input device 35 (touch panel, operation buttons) Etc.) and a display device 36 (liquid crystal display, organic EL display, etc.). These components are connected to each other via a bus 39 so as to communicate with each other.

  The antenna 34 is a directional antenna, for example. The antenna 34 may be provided integrally with the housing of the mobile terminal 30 or may be provided separately from the housing of the mobile terminal 30. When the mobile terminal 30 is used indoors where an obstacle such as a wall exists, the antenna 34 is preferably a circularly polarized directional antenna. The polarization plane of the circularly polarized reflected wave (or standing wave) is inverted when reflected by an obstacle such as a wall, but the reflected wave or standing wave is effective by using a circularly polarized directional antenna. Can be attenuated.

  FIG. 8 shows main functions of the mobile terminal 30. As shown in the figure, the mobile terminal 30 includes a position location signal transmission unit 301, an information transmission / reception unit 302, and an information display unit 303. These functions are realized by hardware included in the mobile terminal 30 or when the central processing unit 31 of the mobile terminal 30 reads out and executes a program stored in the storage device 32.

  Among the functions described above, the position determination signal transmission unit 301 transmits a wireless signal (hereinafter referred to as a position determination signal 1200) used for position determination of the mobile terminal 30 from the wireless communication interface 33. The position location signal transmission unit 301 transmits the position location signal 1200 repeatedly (for example, periodically) at short time intervals, for example.

  The information transmission / reception unit 302 communicates with the server device 10 or the base station 20 by wireless communication using the wireless communication interface 33 or wired communication using the communication network 5, and receives (downloads) information to be presented to the mobile unit 3. 10 or transmission (upload) of various information used in the base station 20 is performed.

  The information display unit 303 outputs information to be presented to the person who is the moving body 3 to the display device 36.

  FIG. 9 shows the main hardware of the base station 20. As shown in the figure, the base station 20 includes a central processing unit 21 (CPU, MPU, etc.), a storage device 22 (semiconductor memory (RAM, ROM, NVRAM, etc.), hard disk device, etc.), and a base station 20 connected to the communication network 5. A communication interface 23 (NIC, wireless communication module, etc.) for connection to a wireless communication interface 24 (wireless communication module, etc.) for performing wireless communication, and a plurality of antennas 25a to 25d (second antennas) (which will be referred to in the following description). The antenna 25 may be collectively referred to), and an antenna changeover switch 26 is provided. These components are communicably connected via a bus 28.

  The central processing unit 21 implements various functions of the base station 20 by reading and executing a program stored in the storage device 22. The wireless communication interface 24 receives the position location signal 1200 transmitted from the mobile terminal 30.

  The antennas 25 are all directional antennas. The antenna changeover switch 26 sequentially selects any one of the plurality of antennas 25 a to 25 d and connects the antenna 25 to the wireless communication interface 24. When the position location system 1 is used indoors where obstacles such as walls exist, it is preferable to use a circularly polarized directional antenna as the antenna 25. Since the plane of polarization of the circularly polarized reflected wave (or standing wave) is inverted when reflected by a wall or the like, the reflected wave (or standing wave) is effectively used by using a circularly polarized directional antenna as the antenna 25. This is because it can be attenuated.

  FIG. 10 shows main functions of the base station 20. As shown in the figure, the base station 20 includes a communication processing unit 201, a position location signal receiving unit 202, a setting information storage unit 203, a position location unit 204, a multipath evaluation information generation unit 205, and a multipath evaluation information transmission unit 206. And a terminal information management unit 207 in charge. 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 communication processing unit 201 controls the communication interface 23 and the wireless communication interface 24 to transmit or receive data with the mobile terminal 30 or the server device 10.

  The location signal receiving unit 202 controls the wireless communication interface 24 and the antenna changeover switch 26 to receive the location signal 1200 transmitted from the mobile terminal 30.

  The setting information storage unit 203 stores the setting information described above (for example, information (latitude, longitude, height H) indicating the current position of the base station 20).

  The location determination unit 204 determines the current location of the mobile terminal 30 managed by the responsible terminal information described later based on the location determination signal 1200. The position locating unit 204 changes the state of the moving object 3 when the position of the moving object 3 (the mobile terminal 30) is determined (for example, when a position determination signal 1200 is received and a preset time arrives). When the time (such as when the mounting position of the mobile terminal 30 is changed) arrives, the current position of the mobile terminal 30 is determined. The determined current position of the mobile terminal 30 is transmitted to the server device 10 and the mobile terminal 30 at any time by the communication processing unit 201 and used for various purposes. The position location mechanism will be described later.

  The multipath evaluation information generation unit 205 generates information (hereinafter referred to as multipath evaluation information) indicating the degree of multipath influence of the position location signal 1200 received from the mobile terminal 30.

  The multipath evaluation information transmission unit 206 transmits the multipath evaluation information generated by the multipath evaluation information generation unit 205 to the server device 10.

  The assigned terminal information management unit 207 manages information (hereinafter referred to as assigned terminal information) that identifies the mobile terminal 30 that the base station 20 is currently in charge of position location. When the terminal ID included in the position determination signal 1200 received from the mobile terminal 30 is included in the responsible terminal information, the position determination unit 204 determines the position of the mobile terminal 30.

  FIG. 11 shows an example of terminal information in charge. As shown in the figure, the responsible terminal information 1100 includes the terminal ID 1111 of the mobile terminal 30 that is currently in charge of location determination.

<Positioning principle>
Next, a mechanism for locating the current position of the mobile terminal 30 performed by the position locating system 1 will be described. As a premise for the following description, it is assumed that the mobile terminal 30 repeatedly transmits the position location signal 1200 at a sufficiently short time interval. In addition, the base station 20 receives the positioning signal 1200 while switching the four antennas 25a to 25d with a sufficiently short period.

  FIG. 12 shows an example of a position location signal 1200 transmitted from the antenna 34 of the mobile terminal 30. As shown in the figure, the position location signal 1200 includes a control signal 1211, a measurement signal 1212, and terminal information 1213. Among these, the control signal 1211 includes a modulated wave and various control signals. The measurement signal 1212 is an unmodulated wave of about several milliseconds (for example, a signal used to detect the direction in which the mobile terminal 30 exists with respect to the base station 20 and the relative distance to the mobile terminal 30 with respect to the base station 20 (for example, 2048). Chip spreading code)). The terminal information 1213 includes the terminal ID of the mobile terminal 30.

  FIG. 13 shows the positional relationship between the base station 20 and the mobile terminal 30. As shown in the figure, the base station 20 is fixed at a height H (m) from the plane Z on which the moving body 3 moves. In addition, the mobile terminal 30 is located at a height h (m) from the plane Z. On the plane Z, the straight line distance from directly below the base station 20 to directly below the mobile terminal 30 is L (m).

  FIG. 14 shows four antennas 25 a to 25 d provided in the base station 20. As shown in the figure, each of the four antennas 25a to 25d has one wavelength of the positioning signal 1200 (for example, a wavelength λ = 12.5 cm when a 2.4 GHz band radio wave is used as the positioning signal 1200). Adjacently arranged in a substantially square shape with a space of the following (for example, 3 cm). The four antennas 25a to 25d are all directional antennas (for example, circularly polarized directional antennas), and the directivity directions of these antennas are directed obliquely downward.

In the figure, if the angle between the horizontal direction at the height of the antenna 25 and the direction of the mobile terminal 30 with respect to the antenna 25 is α, there is the following relationship between them.
α = arcTan (D (m) / L (m)) = arcSin (ΔL (cm) / 3 (cm))
... Formula 1

  ΔL (cm) is a difference in propagation path length between the two specific antennas 25 and the mobile terminal 30 among the antennas 25a to 25d constituting the antenna 25 (hereinafter also referred to as a route difference). .)

Here, among the four antennas 25a to 25d, if the phase difference of the positioning signal 1200 received by two specific antennas 25 is Δθ, the following relationship is established.
ΔL (cm) = Δθ / (2π / λ (cm)) Equation 2

Here, for example, when the positioning signal 1200 is a 2.4 GHz band radio wave (wavelength λ = 12.5 (cm)), α = arcSin (Δθ / π) Equation 3
Thus, α = Δθ (radian) in the measurable range (−π / 2 <Δθ <π / 2), and the direction α in which the base station 20 exists can be specified from the phase difference Δθ.

As shown in FIG. 15, the height from the plane Z of the antenna 25 of the base station 20 is H, the height from the plane Z of the mobile terminal 30 is h, and the position on the plane Z immediately below the base station 20 is the origin. Set orthogonal coordinates (X, Y) on the plane Z and can be obtained from the direction α, the angle formed by the direction of the mobile station 30 from the base station 20 and the X axis can be obtained from ΔΦ (x) and the direction α, If the angle formed by the direction from the base station 20 to the mobile terminal 30 and the Y axis is ΔΦ (y), the positions Δd (x) and Δd (y) of the mobile terminal 30 with respect to the origin can be obtained from the following equations.
Δd (x) = (H−h) × Tan (ΔΦ (x)) Equation 4
Δd (y) = (H−h) × Tan (ΔΦ (y)) Equation 5

If the origin (X1, Y1) is the point where the perpendicular line drawn from the base station 20 to the plane Z intersects the plane Z, the current position (Xx, Yy) of the mobile terminal 30 can be obtained from the following equation.
Xx = X1 + d (x) Expression 6
Yy = Y1 + d (y) Equation 7

Assuming that the position of the mobile terminal 30 is d and the direction in which the mobile terminal 30 is present as seen from the base station 20 obtained by position determination is ΔΦ, the equations 4 and 5 do not specify the coordinate system, It can be expressed as
d = (H−h) × tan ΔΦ Equation 8

  The principle of positioning described above is described in detail in, for example, Japanese Patent Application Laid-Open Nos. 2004-184078, 2005-351877, 2005-351878, and 2006-23261. ing.

  By the way, when positioning is performed by the mechanism described above, an error caused by a frequency deviation generated in the crystal oscillators of the base station 20 and the mobile terminal 30 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 base station 20 and the mobile terminal 30. For example, the antenna changeover switch 26 is switched. If the period is 32 μs, a phase difference (error) of 2400 Hz × 32 μs × 360 ° = 27.65 ° is generated. Therefore, in the position locating system 1 of the present embodiment, this measurement error is canceled as follows.

First, the phase difference Δθ1 of the positioning signal 1200 received by the combination of the first antenna 25a and the second antenna 25b (hereinafter referred to as the first antenna pair) (the phase of the second antenna 25b is determined with reference to the first antenna 25a). The measurement result is based on the difference (path difference) between the propagation path of the positioning signal 1200 from the mobile terminal 30 to the first antenna 25a and the propagation path of the positioning signal 1200 from the mobile terminal 30 to the second antenna 25b. If the generated phase difference is Δθt1 and the measurement error is F1, it can be expressed by the following equation.
Δθ1 = Δθt1 + F1 Equation 9

On the other hand, the phase difference Δθ2 of the positioning signal 1200 received by the combination of the third antenna 25c and the fourth antenna 25d (hereinafter referred to as the second antenna pair) (the phase of the fourth antenna 25d with reference to the third antenna 25c). Is a difference between the propagation path of the positioning signal 1200 from the mobile terminal 30 to the third antenna 25c and the propagation path of the positioning signal 1200 from the mobile terminal 30 to the fourth antenna 25d (path difference). If the phase difference caused by the above is Δθt2 and the measurement error is F2, it can be expressed by the following equation.
Δθ2 = −Δθt2 + F2 Equation 10

Here, if the difference between both sides of Equation 9 and Equation 10 is taken, the result is as follows.
Δθ1−Δθ2 = (Δθt1 − (− Δθt2)) + (F1−F2) Equation 11

As described above, the first antenna pair and the second antenna pair include the path difference of the positioning signal 1200 received by the antennas 25a and 25b of the first antenna pair and the antennas 25c of the second antenna pair. , 25d so that the path difference of the position location signal 1200 received by 25d matches. Therefore, if this value is θt, the value of (Δθt1 − (− Δθt2)) on the right side of Equation 11 is 2θt. On the other hand, the errors F1 and F2 are normally almost the same between the measurement of the first antenna pair and the measurement of the second antenna pair, so the value of (F1-F2) on the right side of Equation 11 is 0 without limit. Close to. Therefore, if these values are substituted into Expression 11 and the expression is modified, the following is obtained.
θt = (Δθ1-Δθ2) / 2 Equation 12

  Thus, by measuring the phase difference with each of the first antenna pair and the second antenna pair, the measurement errors F1 and F2 can be canceled out, and the phase difference θt caused by the path difference can be reduced. It can be acquired with high accuracy. And according to this, the precision of position location can be improved.

  If an AGC (Automatic Gain Controller) or the like is provided on the phase measurement side to reduce the frequency deviation, the value of (F1-F2) on the right side of Equation 11 can be made closer to 0, and the position The accuracy of orientation can be further increased.

= Handover =
Next, handover control performed in the position location system 1 having the above-described configuration will be described.

  FIG. 16 is a flowchart for explaining a process (hereinafter referred to as a handover process (server apparatus) S1600) performed by the server apparatus 10 during handover control. Hereinafter, it will be described with reference to FIG.

  As shown in the figure, the server device 10 monitors whether or not the timing for performing handover control has arrived for each of the mobile terminals 30 that are performing location determination (S1611). In addition, the said timing arrives, for example for every predetermined time (for example, periodically). In addition, the timing comes when, for example, the current position of the mobile terminal 30 enters the vicinity of the boundary of an area where a certain base station 20 can determine the position. The timing comes when, for example, one of the base stations 20 receives a handover execution request from the mobile terminal 30. Further, the above timing arrives, for example, when the degree of multipath influence of the position location signal 1200 received by the base station 20 exceeds a preset threshold.

  When the server apparatus 10 detects that the above timing has arrived for a certain mobile terminal 30 (hereinafter referred to as a target mobile terminal) (S1611: YES), the server apparatus 10 determines the current location of the target mobile terminal from the base station charge status information 500. A base station 20 in charge (hereinafter referred to as a base station in charge) is identified, and one or more other base stations 20 (hereinafter referred to as adjacent base stations) provided adjacent to the base station in charge. ) Is acquired from the base station position information 400 (S1612). For example, the server device 10 checks whether or not the other base station 20 is adjacent to the assigned base station by checking whether or not the linear distance from the assigned base station is equal to or less than a preset distance. to decide.

  Next, the server apparatus 10 transmits a transmission request for multipath evaluation information regarding the position location signal 1200 transmitted from the target mobile terminal to the responsible base station and the acquired adjacent base station (S1613). It waits for reception of multipath evaluation information from all adjacent base stations (S1614). The transmission request includes the terminal ID of the target mobile terminal.

  When the server apparatus 10 receives multipath evaluation information about the position location signal 1200 transmitted from the target mobile terminal from the responsible base station and the adjacent base station (S1614: YES), the multipath evaluation information received from the responsible base station. And the multipath evaluation information received from the adjacent base station, and whether there is an adjacent base station that has received the position location signal 1200 that is less affected by the multipath than the assigned base station from the target mobile terminal. Is determined (S1615).

  When there is an adjacent base station that has received the position location signal 1200 that is less affected by the multipath than the serving base station from the target mobile terminal (S1615: YES), the server device 10 determines that the An adjacent base station that receives the location signal 1200 having the least path influence from the target mobile terminal is selected (S1616). Thereafter, the process proceeds to S1617.

  Note that there are a plurality of adjacent base stations that receive the location signal 1200 having the least multipath effect from the target mobile terminal among the adjacent base stations (a plurality of adjacent base stations that are affected by the same multipath effect). In the case of (exist), for example, the one that is present at the position closest to the current position of the target mobile terminal is selected. For example, the base station 20 is provided with a field strength meter (RSSI or the like) that measures the received field strength of the location signal 1200, and receives the location signal 1200 at the maximum field strength among the plurality of adjacent base stations. An adjacent base station may be selected.

  On the other hand, when there is no adjacent base station that has received the location signal 1200 that is less affected by the multipath than the assigned base station from the target mobile terminal (S1615: NO), the server device 10 switches the base station 20. (Handover) is not performed, and the process returns to S1611.

  In S <b> 1617, the server apparatus 10 transmits an instruction to add information related to the target mobile terminal to the responsible terminal information managed by each of the selected adjacent base stations. In addition, the server device 10 transmits an instruction for deleting information related to the target mobile terminal from the responsible terminal information managed by the responsible base station to the responsible base station.

  Next, the server apparatus 10 adds information indicating the correspondence between the adjacent base station and the target mobile terminal to the base station charge status information 500 of itself and deletes the information indicating the correspondence between the base station in charge and the target mobile terminal ( S1618). Thereafter, the process returns to S1611.

  In the above processing, the server device 10 transmits a transmission request for multipath evaluation information to the responsible base station and the adjacent base station (S1613), and the responsible base station or the adjacent base station passively responds accordingly. The multipath evaluation information is transmitted to the server apparatus 10 at the same time. For example, the base station in charge and the adjacent base station actively transmit the multipath evaluation information to the server apparatus 10 repeatedly at short time intervals. In such a case, the server apparatus 10 may wait for reception of the multipath evaluation information transmitted from the base station in charge and the adjacent base station without transmitting the transmission request from the server apparatus 10.

  FIG. 17 is a flowchart for explaining a process performed by the base station 20 in the handover control (hereinafter referred to as a handover process (base station) S1700). Hereinafter, it will be described with reference to FIG.

  As shown in the figure, the base station 20 waits for reception of a transmission request for multipath evaluation information sent from the server device 10 in the processing of S1613 in FIG. 16 (S1711).

  When receiving the transmission request (S1711: YES), the base station 20 generates multipath evaluation information based on the position location signal 1200 sent from the target mobile terminal (S1712). A specific method for generating multipath evaluation information will be described later.

  Subsequently, the base station 20 transmits the generated multipath evaluation information to the base station 20 together with the base station ID of itself (the base station 20) and the terminal ID of the target mobile terminal.

  As described above, in the position location system 1 of the present embodiment, the server device 10 has the base station 20 that has the least multipath effect based on the multipath evaluation information of the base station in charge and the adjacent base station. Is selected to control the handover between the base stations 20, so that the positioning accuracy is ensured even when the positioning system 1 is used in an environment where the influence of multipath or reflected waves is large. The handover between the base stations 20 can be appropriately controlled.

= Multipath evaluation information generation method =
Next, a specific method for generating multipath evaluation information performed by the base station 20 in S1712 of FIG. 17 will be described.

[First generation method]
First, a principle (determination principle (part 1)) or a determination principle (determination principle) for determining whether or not the position location signal 1200 transmitted from the mobile terminal 30 and received by the base station 20 is a direct wave (multipath). Part 2)) will be described.

(1) Determination principle (1)
The determination principle (part 1) is that the base station 20 measures the phase difference Δθ1 of the positioning signal 1200 received by the antennas 25a and 25b of the first antenna pair (the second antenna 25b with reference to the first antenna 25a). And the phase difference Δθ2 of the positioning signal 1200 received by each antenna 25c, 25d of the second antenna pair is measured (the phase of the third antenna 25c is measured with reference to the fourth antenna 25d). Then, based on the measured phase difference Δθ1 and phase difference Δθ2, it is determined whether or not the position location signal 1200 sent from the mobile terminal 30 is a direct wave.

Here, the phase difference Δθ1 of the positioning signal 1200 received by each antenna (first antenna 25a and second antenna 25b) of the first antenna pair (the result of measuring the phase of the second antenna 25b with reference to the first antenna 25a) ) Is a phase difference caused by a difference (path difference) between the propagation path of the positioning signal 1200 from the mobile terminal 30 to the first antenna 25a and the propagation path of the positioning signal 1200 from the mobile terminal 30 to the second antenna 25b. Is Δθt1, the measurement error is F1, and the influence of multipath or reflected wave is M1, the following equation can be expressed.
Δθ1 = Δθt1 + F1 + M1 Equation 21

Further, the phase difference Δθ2 of the positioning signal 1200 received by each antenna (the third antenna 25c and the fourth antenna 25d) of the second antenna pair (the result of measuring the phase of the third antenna 25c with reference to the fourth antenna 25d) Is a phase difference caused by a difference (path difference) between the propagation path of the position location signal 1200 from the mobile terminal 30 to the third antenna 25c and the propagation path of the position location signal 1200 from the mobile terminal 30 to the fourth antenna 25d. Δθt2 (Because the reference is reversed when measuring the phase, the sign of Δθt2 is reversed in the case of the above-mentioned position determination (Equation 10)), the measurement error is F2, the influence of multipath and reflected wave If M is M2, it can be expressed by the following equation.
Δθ2 = Δθt2 + F2 + M2 Equation 22

Next, if the difference between both sides of Equation 21 and Equation 22 is taken, the result is as follows.
Δθ1−Δθ2 = (Δθt1−Δθt2) + (F1−F2) + (M1−M2)
... Formula 23

As described above, the first antenna pair and the second antenna pair are different from each other in the path difference of the positioning signal 1200 received by each antenna 25a, 25b of the first antenna pair and each of the second antenna pair. Since the path difference of the position location signal 1200 received by the antennas 25c and 25d is provided so as to match, the value of (Δθt1−Δθt2) on the right side of Expression 23 is as close to 0 as possible. Further, as described above, the errors F1 and F2 are usually almost the same between the measurement of the first antenna pair and the measurement of the second antenna pair, so the value of (F1-F2) on the right side of Equation 23 is Infinitely close to 0. Therefore, if these values are substituted, the equation 23 is finally as follows.
Δθ1−Δθ2 = M1−M2 Equation 24

  Here, the antennas 25a and 25b of the first antenna pair and the antennas 25c and 25d of the second antenna pair are different in physical arrangement position as shown in FIG. The influence of the multipath and reflected wave on each of 25d is different, and if the position location signal 1200 is a multipath or reflected wave, M1 ≠ M2. Conversely, if the position location signal 900 is a direct wave, M1 = M2. Therefore, if it is checked whether or not the phase difference Δθ1 and the phase difference Δθ2 match (whether the difference between the two is 0 or at least equal to or less than a preset reference value), the mobile terminal 30 It can be determined whether or not the position positioning signal 900 sent is a direct wave.

  The mechanism described above (determination principle (part 1)) can be applied to the case where either ΔΦ (x) or ΔΦ (y) described above is obtained. That is, when obtaining each of ΔΦ (x) and ΔΦ (y), it is possible to individually determine the presence or absence of a multipath or a reflected wave.

  As described above, according to the determination principle (part 1), it is possible to determine whether or not the position location signal 1200 received from the mobile terminal 30 is a direct wave based on the difference.

(2) Determination principle (2)
The determination principle (No. 2) is that the base station 20 measures the phase difference Δθ1 of the positioning signal 1200 received by each antenna 25a, 25b of the first antenna pair (the second antenna 25b with reference to the first antenna 25a). And the phase difference Δθ2 of the positioning signal 1200 received by the antennas 25c and 25d of the second antenna pair is measured (the phase of the fourth antenna 25d is measured using the third antenna 25c as a reference). Then, based on the measured phase difference Δθ1 and phase difference Δθ2, it is determined whether or not the position location signal 1200 sent from the mobile terminal 30 is a direct wave.

Here, the phase difference Δθ1 of the positioning signal 1200 received by each antenna (first antenna 25a and second antenna 25b) of the first antenna pair (the result of measuring the phase of the second antenna 25b with reference to the first antenna 25a) ) Is a phase difference caused by a difference (path difference) between the propagation path of the positioning signal 1200 from the mobile terminal 30 to the first antenna 25a and the propagation path of the positioning signal 1200 from the mobile terminal 30 to the second antenna 25b. Is Δθt1, the measurement error is F1, and the influence of multipath or reflected wave is M1, the following equation can be expressed.
Δθ1 = Δθt1 + F1 + M1 Equation 31

Further, the phase difference Δθ2 of the positioning signal 1200 received by each antenna (the third antenna 25c and the fourth antenna 25d) of the second antenna pair (the result of measuring the phase of the fourth antenna 25d with reference to the third antenna 25c) Is a phase difference caused by a difference (path difference) between the propagation path of the position location signal 1200 from the mobile terminal 30 to the third antenna 25c and the propagation path of the position location signal 1200 from the mobile terminal 30 to the fourth antenna 25d. Δθt2 (Because the reference is the same when measuring the phase, the sign of Δθt2 is the same as in the case of the above-mentioned position determination (equation 10)), and the measurement error is F2, the influence of multipath and reflected wave Is M2 (because the reference is the same when measuring the phase, the sign coincides with Δθt2).
Δθ2 = −Δθt2 + F2-M2 Expression 32

Next, if the sum of both sides of Equation 31 and both sides of Equation 32 is taken, the result is as follows.
Δθ1 + Δθ2 = (Δθt1−Δθt2) + F1 + F2 + (M1−M2)
... Formula 33

As described above, the first antenna pair and the second antenna pair are different from each other in the path difference of the positioning signal 1200 received by each antenna 25a, 25b of the first antenna pair and each of the second antenna pair. Since it is provided so that the path difference of the location signal 1200 received by the antennas 25c and 25d matches, the value of (Δθt1−Δθt2) on the right side of Expression 33 is zero. Therefore, Expression 33 is as follows.
Δθ1 + Δθ2 = (F1 + F2) + (M1-M2) Expression 34

  Here, when F1 and F2 are sufficiently stable (time fluctuation is small), the value of (F1 + F2) (if F1 and F2 are equal (this value is assumed to be F) (F1 + F2) = 2F) is substantially constant. Can be considered. For this reason, if (F1 + F2) is known in advance as an empirical value or the like, whether or not the value Δθ1 + Δθ2 on the left side of Expression 34 coincides with (F1 + F2) (whether the difference between the two is 0 or at least preset) It is possible to determine whether or not the position location signal 1200 sent from the mobile terminal 30 is a direct wave by checking whether or not it is equal to or less than a reference value (in the case of a direct wave, M1 = 0, Since M2 = 0, (M1-M2) = 0, and when not a direct wave, M1 ≠ 0 and M2 ≠ 0 (M1-M2) ≠ 0).

  Note that the mechanism described above (determination principle (part 2)) can be applied to the determination of either ΔΦ (x) or ΔΦ (y) described above. That is, when obtaining each of ΔΦ (x) and ΔΦ (y), it is possible to individually determine the presence or absence of a multipath or a reflected wave.

  As described above, according to the determination principle (part 2), the error included in each of the phase difference Δθ1 and the phase difference Δθ2 is sufficiently stable compared to the component due to the influence of the indirect wave, As long as the error value (F1 + F2) is given as an empirical value, it can be determined based on the above sum whether or not the location signal 1200 received from the mobile terminal 30 is a direct wave.

  In the determination principle (No. 2), it is determined whether or not the position location signal 1200 received from the mobile terminal 30 is a direct wave. The phase difference Δθ1 and the phase difference Δθ2 measured to determine the position of the mobile terminal 30 are used. (Δθ2 measured using a measurement standard whose sign is inverted with respect to the measurement result of the phase difference Δθ1) can be used as it is, so that the position determination of the mobile terminal 30 and the position determination signal 1200 are direct waves. The determination of whether or not can be done by a single measurement, and the processing load on the base station 20 and the mobile terminal 30 related to determining whether the position determination and the position determination signal 1200 are direct waves can be reduced. is there.

(3) Multipath evaluation information In the above-described determination principle (part 1), it is determined whether or not the position location signal 1200 is a direct wave by examining the difference between the phase difference Δθ1 and the phase difference Δθ2. (Equation 24) The value of the difference obtained in this determination indicates the degree of multipath influence of the position determination signal 1200, and the position determination is such that the difference between the phase difference Δθ1 and the phase difference Δθ2 is close to zero. The signal 1200 indicates that the degree of multipath influence is small.

  Therefore, in the case of the determination principle (part 1), it is possible to determine the multipath influence level of the position location signal 1200 based on the difference between the phase difference Δθ1 and the phase difference Δθ2, and use the difference as multipath evaluation information. Can do.

  In the above-described determination principle (part 2), it is determined whether or not the position location signal 900 is a direct wave by examining the sum of the phase difference Δθ1 and the phase difference Δθ2 (Equation 34). The value of the sum obtained at the time of determination indicates the degree of multipath influence of the position determination signal 1200. The position determination signal 900 in which the sum of the phase difference Δθ1 and the phase difference Δθ2 is close to F1 + F2, This indicates that the degree of influence is small.

  Therefore, in the case of the determination principle (part 2), it is possible to determine the multipath influence degree of the position location signal 1200 based on the sum of the phase difference Δθ1 and the phase difference Δθ2, and use the sum as the multipath evaluation information. it can.

(4) Specific Configuration FIG. 18 shows a configuration of the multipath evaluation information acquisition unit 107 shown in FIG. 3 in the case where multipath evaluation information is acquired by the first generation method described above.

  As shown in the figure, the multipath evaluation information acquisition unit 107 includes a first phase difference measurement unit 1071, a second phase difference measurement unit 1072, and an evaluation information generation storage unit 1073.

  Among these, the first phase difference measurement unit 1071 is transmitted from the mobile terminal 30 by the first antenna pair (combination of the first antenna 25a and the second antenna 25b) among the four antennas 25a to 25d of the base station 20. The incoming position location signal 1200 is received, and the phase difference Δθ1 of the position location signal 1200 received by each of the first antenna 25a and the second antenna 25b is measured.

  The second phase difference measuring unit 1072 is a position transmitted from the mobile terminal 30 by the second antenna pair (combination of the third antenna 25c and the fourth antenna 25d) among the four antennas 25a to 25d of the base station 20. The orientation signal 1200 is received, and the phase difference Δθ2 of the position orientation signal 1200 received by each of the third antenna 25c and the fourth antenna 25d is measured.

  The first antenna pair and the second antenna pair are determined by the path difference of the positioning signal 1200 received by the antennas 25a and 25b of the first antenna pair and the antennas 25c and 25d of the second antenna pair. It is positioned and provided so that the path difference of the received position location signal 1200 matches.

  The evaluation information generation storage unit 1073 is based on the phase difference Δθ1 acquired by the first phase difference measurement unit 1071 and the phase difference Δθ2 acquired by the second phase difference measurement unit 1072 (part 1). Alternatively, multipath evaluation information is generated according to the determination principle (part 2).

[Second generation method]
Next, a second method for generating multipath evaluation information will be described.

  According to the principle of spatial diversity, when the physical position of the mobile terminal 30 differs by about 1/4 wavelength to 1 wavelength in an indirect wave composed of a plurality of reflected waves and direct waves, the position location signal 1200 is given. The degree of multipath influence changes. For this reason, the base station 20 is provided with, for example, a number of antennas 25 that can form a plurality of antenna groups 25 by selecting the antennas that constitute the first antenna pair and the second antenna pair. If the position location signal 1200 is received, the location location signal 1200 having a different degree of multipath influence can be acquired.

  FIG. 19 shows an example of a method for realizing the pattern of the antenna group 25. As shown in the figure, in this example, the base station 20 has the same antenna in order to configure the antenna group 25 including the first antenna pair and the second antenna pair over four patterns A, B, C, and D. Nine antennas 25 are provided on the base 191. In the figure, the interval between adjacent antennas 25 is about 1/4 wavelength to 1 wavelength of the position location signal 1200.

  The figure shows only an example of a method for realizing the pattern of the antenna group 25, and the pattern of the antenna group 25 can be realized by other methods. However, the pattern of the antenna group 25 needs to be provided so that the degree of multipath influence of each pattern can be compared when the position determination is performed based on the same position determination signal 1200.

  In the figure, the antenna group 25A of pattern A is composed of four antennas 25Aa, 25Ab, 25Ac, and 25Ad in the lower left of the antenna base 191. In this pattern A, the antenna 25Aa and the antenna 25Ab constitute a first antenna pair, and the antenna 25Ac and the antenna 25Ad constitute a second antenna pair.

  The antenna group 25B of the pattern B is configured by four antennas 25Ba, 25Bb, 25Bc, and 25Bd at the lower right of the antenna base 191. In the pattern B, the antenna 25Ba and the antenna 25Bb constitute a first antenna pair, and the antenna 25Bc and the antenna 25Bd constitute a second antenna pair.

  The antenna group 25C of the pattern C includes four antennas 25Ca, 25Cb, 25Cc, and 25Cd on the upper right side of the antenna base 191. In this pattern C, the antenna 25Ca and the antenna 25Cb constitute a first antenna pair, and the antenna 25Cc and the antenna 25Cd constitute a second antenna pair.

  The antenna group 25D of the pattern D is composed of four antennas 25Da, 25Db, 25Dc, and 25Dd at the upper left of the antenna base 191. In this pattern D, the antenna 25Da and the antenna 25Db constitute a first antenna pair, and the antenna 25Dc and the antenna 25Dd constitute a second antenna pair.

  Here, when the mobile terminal 30 exists outside the area that can be determined, the variation in the position determination result between the patterns becomes large. For this reason, the degree of variation between patterns in the result of the position determination performed by each pattern indicates the degree of multipath influence of the position determination signal 1200 transmitted from the mobile terminal 30 and received by the base station 20. Thus, the degree of variation between the patterns as a result of the position determination performed by each pattern can be used as multipath evaluation information.

  In addition, the degree of variation between each pattern of the positioning result by each pattern is grasped by, for example, taking the difference between the maximum value and the minimum value of the positioning result of each pattern and the dispersion of the positioning result of each pattern. can do.

  As mentioned above, although embodiment of this invention was described in detail, the above description is for making an understanding of this invention easy, and does not limit this 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 positioning signal 1200 is transmitted from the antenna 34 of the mobile terminal 30 and received by the antenna 25 of the base station 20 to perform positioning. A location signal 1200 is transmitted from the base station 20, the mobile terminal 30 receives the location signal 1200, the mobile terminal 30 selects an antenna 34 that is likely to receive a direct wave, and the selected antenna 34 The location may be determined based on the location signal 1200 received. Further, if information indicating the current position of the mobile terminal 30 determined by the mobile terminal 30 is transmitted from the mobile terminal 30 to the server device 10 or the base station 20 by the communication network 5 or wireless communication, the server device 10 or the base station The station 20 can grasp the current position of the moving body 3.

  For example, the mobile terminal 30 may function as an active or passive RFID tag. In this case, the position location signal 1200 may be transmitted to or received from the base station 20 spontaneously or passively from an antenna coil included in the RFID tag by electromagnetic induction.

  Further, the degree of influence of multipath usually differs for each coordinate axis (for example, the X axis and the Y axis in the orthogonal coordinates (X, Y) described above). Therefore, in the above-described handover control, the server device 10 may select the base station 20 that is less affected by multipath for each coordinate axis and perform the location of the mobile terminal 30. When positioning is performed by selecting a different base station 20 for each coordinate axis, for example, the base station 20 or the server device 10 out of them may combine the results of the position determination for each coordinate axis. The current position of the mobile terminal 30 is obtained (by obtaining ΔΦ from ΔΦ (x) and ΔΦ (x)). In this way, the position of the mobile terminal 30 can be determined by the position determination signal 1200 that is less affected by multipath individually for each coordinate axis, and the position accuracy can be improved.

DESCRIPTION OF SYMBOLS 1 Location system 3 Mobile body 10 Server apparatus 104 Handover control part 105 Base station position information management part 106 Base station charge situation management part 107 Multipath evaluation information acquisition part 20 Base station 204 Location determination part 205 Multipath evaluation information generation part 206 Multipath evaluation information transmitting unit 207 Responsible terminal information management unit 30 Mobile terminal 400 Base station location information 500 Base station responsible status information 600 Multipath evaluation information 1100 Responsible terminal information S1600 Handover processing (server device)
S1700 Handover processing (base station)

Claims (12)

Including a mobile terminal and a plurality of base stations having a plurality of antennas arranged adjacent to each other;
The mobile terminal transmits a location signal, which is a radio signal used to locate the location of the mobile terminal;
The base station obtains a direction ΔΦ in which the mobile terminal exists as seen from the base station based on the phase difference Δθ of the positioning signal received by each of the antennas, and moves based on the obtained direction ΔΦ. A method for controlling a location system that performs terminal location,
Providing a server device communicably connected to each of the plurality of base stations;
The server device
Receiving multipath evaluation information from the base station, which is information indicating the degree of multipath influence of the location signal received from the mobile terminal;
Based on the received multipath evaluation information, select the base station having the least multipath influence,
A control method for a position location system, which controls the base station and other base stations so that the mobile terminal is located by the selected base station. A control method for a position location system according to claim 1,
The base station is connected to the first antenna pair and the second antenna pair by the path difference of the positioning signal received by each antenna of the first antenna pair and each antenna of the second antenna pair. Provided to match the path difference of the received position location signal,
The base station is
A direction in which the mobile terminal exists is obtained based on the phase difference Δθ 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 Find the position of the moving object,
Measuring the phase difference Δθ1 of the positioning signals received by each antenna of the first antenna pair;
Measuring the phase difference Δθ2 of the positioning signals received by each antenna of the second antenna pair;
Based on the phase difference Δθ1 and the phase difference Δθ2, obtain the degree of multipath influence of the positioning signal,
A control method for a position location system, wherein the obtained degree of influence of the multipath is transmitted to the server device as the multipath evaluation information. A control method for a position location system according to claim 1,
The base station receives the first antenna pair and the second antenna pair by the path difference of the positioning signal received by each antenna of the first antenna pair and each antenna of the second antenna pair. Provided to match the path difference of the position location signal,
The base station determines a direction in which the mobile terminal exists based on a phase difference Δθ of the positioning signals received by each antenna of the first antenna pair or each antenna of the second antenna pair. Obtaining the position of the moving body based on the direction;
The base station
Measuring the phase difference Δθ1 of the positioning signals received by each antenna of the first antenna pair;
Measuring the phase difference Δθ2 of the positioning signals received by each antenna of the second antenna pair;
The base station is provided with a number of antennas that can form a plurality of patterns of antenna groups including the first antenna pair and the second antenna pair,
Based on the phase difference Δθ1 and the phase difference Δθ2 measured for each of the patterns, the degree of influence of each multipath of the pattern is obtained,
A control method for a position location system, wherein the obtained variation of the influence degree of the multipath of the pattern is transmitted to the server device as the multipath evaluation information. A control method for a position location system according to claim 2, comprising:
The base station
The position of the mobile terminal is measured by measuring the phase difference Δθ1 and the phase difference Δθ2 using a measurement standard in which the measurement result of the phase difference Δθ2 is reversed in sign with respect to the measurement result of the phase difference Δθ1. In order to cancel out the errors included in each of the phase difference Δθ1 and the phase difference Δθ2, it is obtained by taking the difference between the phase difference Δθ1 and the phase difference Δθ2.
The degree of influence of the multipath of the positioning signal received from the mobile terminal is measured using the measurement reference in which the measurement result of the phase difference Δθ2 and the sign of the measurement result of the phase difference Δθ1 coincide with each other. A method for controlling a position location system, which is obtained as a difference between the phase difference Δθ1 measured by measuring a phase difference Δθ2 and the phase difference Δθ2. A control method for a position location system according to claim 2, comprising:
The base station
The position of the mobile terminal is measured by measuring the phase difference Δθ1 and the phase difference Δθ2 using a measurement standard in which the measurement result of the phase difference Δθ2 is reversed in sign with respect to the measurement result of the phase difference Δθ1. In order to cancel out the errors included in each of the phase difference Δθ1 and the phase difference Δθ2, it is obtained by taking the difference between the phase difference Δθ1 and the phase difference Δθ2.
A method for controlling a position location system, wherein the degree of influence of the multipath of the position location signal received from the mobile terminal is obtained as a sum of the measured phase difference Δθ1 and phase difference Δθ2. It is a control method of the position location system according to any one of claims 1 to 5,
Each of the base stations generates multipath evaluation information that is information indicating the degree of influence of multipath for each coordinate axis direction component of the positioning signal received from the mobile terminal, and transmits this to the server device.
The server device
Receiving the multipath evaluation information transmitted from each of the base stations;
Based on the received multipath evaluation information, select the base station with the least multipath influence degree for each coordinate axis direction component,
A control method for a position location system, wherein the base station and other base stations are controlled such that the mobile terminal is located by the base station individually selected for each component of the coordinate axis direction. A mobile terminal,
A plurality of base stations having a plurality of antennas arranged adjacent to each other;
A server device communicably connected to each of the plurality of base stations,
The mobile terminal transmits a location signal, which is a radio signal used to locate the location of the mobile terminal;
The base station obtains a direction ΔΦ in which the mobile terminal exists as seen from the base station based on the phase difference Δθ of the positioning signal received by each of the antennas, and moves based on the obtained direction ΔΦ. A location system for positioning a terminal,
The server device
Receiving multipath evaluation information from the base station, which is information indicating the degree of multipath influence of the location signal received from the mobile terminal;
Based on the received multipath evaluation information, select the base station having the least multipath influence,
A position location system that controls the base station and other base stations so that the location of the mobile terminal is determined by the selected base station. The location system according to claim 7,
In the base station, the first antenna pair and the second antenna pair are received by the path difference of the positioning signal received by each antenna of the first antenna pair and each antenna of the second antenna pair. Provided so that the path difference of the position location signal to be matched,
The base station
A direction in which the mobile terminal exists is obtained based on the phase difference Δθ 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 Find the position of the moving object,
Measuring the phase difference Δθ1 of the positioning signals received by each antenna of the first antenna pair;
Measuring the phase difference Δθ2 of the positioning signals received by each antenna of the second antenna pair;
Based on the phase difference Δθ1 and the phase difference Δθ2, obtain the degree of multipath influence of the positioning signal,
A location system that transmits the obtained degree of influence of the multipath to the server apparatus as the multipath evaluation information. The location system according to claim 7,
In the base station, the first antenna pair and the second antenna pair are received by the path difference of the positioning signal received by each antenna of the first antenna pair and each antenna of the second antenna pair. Provided so that the path difference of the position location signal to be matched,
The base station
A direction in which the mobile terminal exists is obtained based on the phase difference Δθ 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 Find the position of the moving object,
Measuring the phase difference Δθ1 of the positioning signals received by each antenna of the first antenna pair;
Measuring the phase difference Δθ2 of the positioning signals received by each antenna of the second antenna pair;
The base station is provided with a number of antennas that can form a plurality of patterns of antenna groups including the first antenna pair and the second antenna pair,
The base station
Based on the phase difference Δθ1 and the phase difference Δθ2 measured for each of the patterns, the degree of influence of each multipath of the pattern is obtained,
A control method for a position location system, wherein the obtained variation of the influence degree of the multipath of the pattern is transmitted to the server device as the multipath evaluation information. A location system according to claim 8 or 9, wherein
The base station
The position of the mobile terminal is measured by measuring the phase difference Δθ1 and the phase difference Δθ2 using a measurement standard in which the measurement result of the phase difference Δθ2 is reversed in sign with respect to the measurement result of the phase difference Δθ1. In order to cancel out the errors included in each of the phase difference Δθ1 and the phase difference Δθ2, it is obtained by taking the difference between the phase difference Δθ1 and the phase difference Δθ2.
The degree of influence of the multipath of the positioning signal received from the mobile terminal is measured using the measurement reference in which the measurement result of the phase difference Δθ2 and the sign of the measurement result of the phase difference Δθ1 coincide with each other. A position location system that obtains the difference between the phase difference Δθ1 and the phase difference Δθ2 measured by measuring the phase difference Δθ2. A location system according to claim 8 or 9, wherein
The base station
The position of the mobile terminal is measured by measuring the phase difference Δθ1 and the phase difference Δθ2 using a measurement standard in which the measurement result of the phase difference Δθ2 is reversed in sign with respect to the measurement result of the phase difference Δθ1. In order to cancel out the errors included in each of the phase difference Δθ1 and the phase difference Δθ2, it is obtained by taking the difference between the phase difference Δθ1 and the phase difference Δθ2.
A position location system that obtains the degree of multipath influence of the position location signal received from the mobile terminal as the sum of the measured phase difference Δθ1 and phase difference Δθ2. The position location system according to any one of claims 7 to 11,
Each of the base stations generates multipath evaluation information that is information indicating the degree of influence of multipath for each coordinate axis direction component of the positioning signal received from the mobile terminal, and transmits this to the server device.
The server device
Receiving the multipath evaluation information transmitted from each of the base stations;
Based on the received multipath evaluation information, select the base station with the least multipath influence degree for each coordinate axis direction component,
A position location system that controls the base station and other base stations so that the position of the mobile terminal is determined by the base station individually selected for each coordinate axis direction component.

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