JP2009077078A - Position detection system - Google Patents

Abstract

A position detection system having a mobile station with low radio wave transmission power is provided.
A mobile station transmits a plurality of radio waves for a single positioning by using a plurality of directional antennas, and in three or more base stations, a mobile station is provided. The reception time of radio waves from is measured. In the positioning server 14, out of the reception times of the radio waves measured by each of the base stations 12, the reception time of the radio waves by transmissions other than a predetermined reference transmission among the multiple transmissions of radio waves by the mobile station 10 is set. The mobile station 10 converts the radio wave reception time by reference transmission based on the radio wave transmission interval by the mobile station 10 and detects the position of the mobile station 10 by the reception time of the radio wave by reference transmission. Therefore, it is not necessary for all base stations 12 to receive radio waves, and the radio wave transmission power of the mobile station 10 can be reduced.
[Selection] Figure 5

Description

  The present invention relates to a position detection system in which a base station receives radio waves transmitted from a mobile station and detects the position of the mobile station based on the reception result, and in particular, the mobile station performs positioning once. In particular, the present invention relates to a technique for reducing transmission power of a mobile station by transmitting a plurality of radio waves having different communication ranges.

  A position detection system that receives radio waves transmitted by a mobile station at a plurality of base stations and detects the position of the mobile station based on a reception time difference that is a difference in reception times of radio waves at each of the plurality of base stations. Proposed. For example, this is the technique described in Patent Document 1.

  In such a position detection system, when a mobile station moves on a two-dimensional plane, for example, radio waves transmitted from the mobile station are received by at least three base stations for detecting the position of the mobile station. The reception time difference between these base stations needs to be calculated. Similarly, when a mobile station moves in a three-dimensional space, it is necessary to receive radio waves transmitted from the mobile station by at least four base stations.

JP 2004-242122 A

  That is, for example, when a mobile station moves on a plane, at least three base stations do not exist within the reach (communication range) of radio waves transmitted from the mobile station, and are moved by at least three base stations. If the radio wave transmitted from the station is not received, the position of the mobile station cannot be detected. In such a case, in order to detect the position of the mobile station, the base station installation interval is reduced so that radio waves transmitted from the mobile station can always be received by at least three base stations. Or the mobile station needs to increase the output so that the radio wave reaches at least three base stations and transmit the radio wave.

  However, installing many base stations is not desirable from the viewpoint of cost increase in the construction of a position detection system. On the other hand, an increase in radio wave output of the mobile station leads to an increase in the size of the device and an increase in power consumption. Therefore, there is a problem that it is difficult to achieve both compatibility in the case of downsizing the mobile station and simplifying the structure.

  The present invention has been made against the background of the above circumstances, and the object of the present invention is to move by transmitting a plurality of radio waves having different communication ranges from each other for a single positioning. An object of the present invention is to provide a mobile station position detection system capable of reducing power consumption associated with transmission of radio waves from a station.

  In Patent Document 1, a position detection system for a mobile station that includes two antennas and includes a mobile station that transmits radio waves by switching these two antennas has been proposed. The accuracy is improved by repeating the measurement while shifting, and the configuration and purpose of the invention are completely different from those of the present invention. That is, the radio waves transmitted from the two antennas described in Patent Document 1 are transmitted so as to be received by all necessary base stations.

  The invention according to claim 1 for solving such a problem includes (a) a transmitting means for transmitting radio waves, a movable mobile station, and a receiving means for receiving radio waves transmitted by the mobile station; Distance-related information measuring means for measuring distance-related information that is information related to the distance to the mobile station based on the received radio wave, and a plurality of clocks fixed at known positions and synchronized with each other In a position detection system comprising a base station and a positioning server that calculates the position of the mobile station based on distance-related information measured by each of the plurality of base stations, (b) the transmitting means (C) The plurality of base stations are composed of three or more base stations, and (d) the distance-related information is: Of each base station (E) the positioning server receives one time by the mobile station among the distance related information measured by each of the plurality of base stations. A base station that received multiple times of distance-related information corresponding to radio waves transmitted by a transmission other than a standard transmission, which is a predetermined single transmission out of a plurality of transmissions for positioning. Distance-related information conversion means for converting into distance-related information corresponding to a reference transmission based on reception intervals in receiving a plurality of radio waves by (f), and (f) distance-related information measured by each of the plurality of base stations Among them, from the distance related information corresponding to the radio wave transmitted by the reference transmission and the distance related information converted by the distance related information conversion means, in the reference transmission Calculating an arrival time difference in each of the plurality of base station of the original electric wave from the moving station, to have a positioning means for calculating the position of the mobile station based on 該到 us time difference, in.

  In this way, in the mobile station, the transmitting means transmits a plurality of times of radio waves having different communication ranges for one positioning, and in three or more base stations, the distance-related The information measurement means measures the reception time of the radio wave from the mobile station as the distance related information. In the positioning server, the distance related information conversion means includes the distance related information measured by each of the plurality of base stations. A plurality of distance related information corresponding to radio waves transmitted by a transmission other than a reference transmission that is a predetermined one out of a plurality of transmissions of radio waves for one positioning by the mobile station, The base station that has received the radio signal is converted into distance-related information corresponding to the reference transmission based on the reception interval in the reception of the radio wave multiple times, and the positioning means is provided by each of the base stations. Out of the distance-related information to be measured, the distance-related information corresponding to the radio wave transmitted by the reference transmission and the distance-related information converted by the distance-related information conversion means are transmitted from the mobile station in the reference transmission. Since the arrival time difference of each of the plurality of base stations of the received radio wave is calculated and the position of the mobile station is calculated based on the arrival time difference, all the base stations transmit the radio wave once by the mobile station. There is no need to receive, and the transmission power of the radio wave of the mobile station can be reduced.

  Preferably, the transmitting means of the mobile station is configured to perform the plurality of times such that each communication range in the plurality of times of radio wave transmission overlaps at least one communication range of communication ranges in other transmissions. Transmitting radio waves. In this way, since any one of the base stations is located in a region where the respective communication ranges in the multiple times of radio wave transmission overlap, a plurality of radio waves transmitted by multiple times of radio wave transmission can be transmitted. Can be received.

  Preferably, the mobile station has a plurality of directional antennas having different directivities, and the transmitting means switches the plurality of directional antennas of the mobile station to transmit the plurality of radio waves. Do. In this way, in the mobile station, the transmitting means switches the plurality of directional antennas to transmit the plurality of radio waves, so that one base station receives the plurality of radio waves, and the mobile station The other base stations necessary for detecting the position of the mobile station only need to receive one of these radio waves transmitted multiple times, and the mobile station has all the base stations required for detecting the position of the mobile station. It is no longer necessary to output radio waves with a receivable intensity, and the transmission power of radio waves from the mobile station can be reduced.

  Also preferably, the mobile station has a directional antenna whose directivity can be changed, and the transmitting means performs a plurality of times with the directivity of the directional antenna being different from each other for one positioning. Transmits radio waves. In this way, in the mobile station, the transmitting means switches the directivities of the directional antennas whose directivities can be changed to different states and transmits the radio waves a plurality of times. Receives the multiple times of radio waves, and other base stations required for detecting the position of the mobile station need only receive one of these multiple times of radio waves, and the mobile station It is no longer necessary to output radio waves at an intensity that can be received by all base stations necessary for position detection, and the transmission power of radio waves from mobile stations can be reduced.

  Preferably, the distance-related information conversion means corresponds to the radio wave generated by the first transmission in the base station that has received radio waves generated by two or more transmissions of the plurality of radio wave transmissions among the plurality of base stations. Distance-related information is converted based on the reception time difference between the reception time, which is distance-related information, and the reception time, which is distance-related information corresponding to the radio wave transmitted by the second transmission. In this way, the reception of the reception time of the first radio wave and the reception time of the second radio wave at the base station that has received both the radio wave by the first transmission and the radio wave by the second transmission. The distance related information can be converted based on the time difference.

  Preferably, the transmission means transmits the radio wave a plurality of times at a predetermined transmission interval, and the distance related information conversion means calculates the reception time difference based on the transmission time difference which is the predetermined transmission interval. Then, the distance related information is converted based on the calculated reception time difference. In this way, since the transmission interval of the radio wave in the transmission unit is a predetermined value, the distance related information conversion unit can easily calculate the distance by calculating the reception time difference based on the predetermined transmission interval. Related information can be converted.

  Hereinafter, an embodiment of the present invention will be described in detail with reference to the drawings.

  FIG. 1 is a diagram showing an example of the configuration of the mobile station position estimation system of the present invention. In FIG. 1, a movable area 50 formed of a square having a side 30 (m) is provided as an area in which a mobile station 10 provided in an arbitrary shape on a plane can move. Further, in the movable area 50, as a base station 12 having a function of performing wireless communication with the mobile station 10 described later, a first base station 12A, a second base station 12B, a third base station 12C, a fourth base station Four base stations of station 12D are provided respectively. Note that the position of the mobile station can be calculated more accurately as the number of base stations increases. In FIG. 1, one base station 12A to 12D is arranged at each of the four corners of a square movable area 50, which satisfies this requirement. Further, the mobile station 10 is arranged in the movable area 50 and is movable in the movable area 50. In the present embodiment, the number of mobile stations 10 is one, but the number of mobile stations is not particularly limited. In addition, a positioning server 14 is provided that is communicable with the base station 12 by, for example, a wired cable 52, and the mobile station 10 transmits the mobile station 10 based on radio waves transmitted by the mobile station 10 and received by the base station 12. The position of the mobile station 10 in the possible area is calculated. In the present specification, the individual base stations 12A to 12D are referred to as base stations 12 unless otherwise distinguished.

  FIG. 2 is a functional block diagram showing an outline of the configuration of the mobile station 10. The mobile station 10 has two directional antennas, a first antenna 21 and a second antenna 22 that transmit and receive radio waves. The antenna switching unit 24 switches whether the antenna used when the mobile station 10 transmits and receives radio waves is the first antenna 21 or the second antenna 22. The first antenna 21 and the second antenna 22 are antennas having directivities such as, for example, planar patch antennas, the directivities thereof are different from each other, and radio waves transmitted from the first antenna 21 can be received. The mobile station 10 is attached so that a part of the area and a part of the area where the radio wave transmitted by the second antenna 22 can be received overlap.

  FIG. 5 is a diagram illustrating an example of directivity of each of the first antenna 21 and the second antenna 22. Since the first antenna 21 and the second antenna 22 are installed such that their directivities are different from each other, the first antenna communicable area 71 which is an area where radio waves transmitted from the first antenna 21 can be received, The second antenna communicable area 72, which is an area where radio waves transmitted from the second antenna 22 can be received, is as shown in FIG. The first antenna communicable area 71 and the second antenna communicable area 72 are partially overlapped with each other.

  The wireless communication unit 26 performs wireless communication with the mobile station 10 and corresponds to a transmission means when the mobile station 10 transmits radio waves. Specifically, the signal generated by the signal processing unit 28, which will be described later, is modulated into a format suitable for communication, and a synthesized wave synthesized with a carrier wave of a predetermined frequency is amplified by an amplifier, and is not corrected by a balun or the like. Convert a balanced line to a balanced line. The radio wave generated in this way is transmitted by the first antenna 21 and / or the second antenna 22 switched by the antenna switching unit 24.

  When the mobile station 10 transmits a radio wave, the signal processing unit 28 transmits information to be transmitted such as a radio wave transmission time, for example, an M-sequence code or a Gold sequence code (pseudo noise code (pseudo noise code) used also in GPS. -Noise code (PN signal) is a kind of code having the property of PN signal), and spreading processing such as spread spectrum is performed using a spreading code such as) to generate a signal to be transmitted. Using such spread spectrum, when communication between a specific mobile station and a base station is performed using a specific spread code, other mobile stations and base stations at the same time and at the same frequency If communication with is performed using another spreading code, mutual communication is not affected.

  The control unit 30 controls operations of the antenna switching unit 24, the wireless communication unit 26, the signal processing unit 28, and the like. For example, when receiving a command for transmitting a radio wave to the base station 12 in order to measure the position of the mobile station 10, first, a signal generated by the signal processing unit 28 as a first transmission is transmitted by the first antenna 21. Then, the antenna switching unit 24 switches the antenna to be used from the first antenna 21 to the second antenna 22, and the signal generated by the signal processing unit 28 is transmitted by the second antenna 22 as a second transmission.

  Further, the control unit 30 switches the operation of the antenna switching unit 24, the wireless communication unit 26, the signal processing unit 28, and the like depending on whether the mobile station 10 transmits (transmits) radio waves or receives radio waves. Control. That is, when the mobile station 10 receives radio waves, the radio communication unit 26 and the signal processing unit 28 perform the following operation instead of the above-described operation. For example, the radio communication unit 26 performs demodulation processing such as digital demodulation corresponding to the communication method on the radio waves received by the first antenna 21 and / or the second antenna 22 that are switched by the antenna switching unit 24. Then, the signal processing unit 28 performs despreading processing corresponding to the diffusion processing performed at the time of transmission on the signal demodulated by the wireless communication unit 26, and extracts information contained in the received radio wave. In this way, the operation of the mobile station 10 can be controlled wirelessly.

Further, the clock 31 is used when the mobile station 10 determines the transmission time of the radio wave, and is used when the mobile station 10 is operated at predetermined intervals, for example. The clock 31 of the base station 12 is clocked as necessary so that the time of the clock 31 matches the time of the clock 44 of each of the base stations 12. Although detailed description is omitted, for example, the following method is used. The mobile station 10 is installed at a known position, receives time information from the base station 12 serving as a reference for time adjustment, and sets a time corrected by addition of radio wave propagation time corresponding to the arrival distance. For example, the mobile station 10 is moved to the center (see FIG. 1) of the movable area 50 that is set to a known position, and the time information is transmitted from any of the base stations 12 (the time at the time of transmission is included as the content of the information) Send radio waves). When the mobile station 10 receives the time information of any one of the base stations 12, the reception time is determined by the distance between the mobile station 10 and any one of the base stations 12. Propagation of radio waves between the mobile station 10 obtained by dividing a certain 30 × √2 / 2 (m) by the radio wave velocity c (2.997 × 10 ⁸ (m / s)) and any one of the base stations 12 The time of the clock 31 of the mobile station 10 is set so that the time is added.

  FIG. 3 is a functional block diagram showing an outline of the configuration of the base station 12. The difference between the base station 12 and the mobile station 10 is that only one antenna 32 is provided as an antenna for transmitting and receiving radio waves, and accordingly, the antenna switching unit 24 is not provided, and a wired cable 52 is used. A server communication unit 40 for performing communication with the positioning server 14 to be described later, and a reception time measuring unit 42 for detecting the synchronization of the spread radio wave by despreading processing and measuring the reception time. On the other hand, the radio communication unit 34, the signal processing unit 36, and the control unit 38 in the base station 12 have the same functions as the radio communication unit 26, the signal processing unit 28, and the control unit 30 in the mobile station 10, respectively.

  That is, the wireless communication unit 34 performs wireless communication with the base station 12 and corresponds to a receiving unit when the base station 12 receives radio waves. Specifically, the radio communication unit 34 performs a demodulation process such as digital demodulation corresponding to the communication method on the radio wave received by the antenna 32.

  Further, the signal processing unit 36 performs despreading processing corresponding to the diffusion processing performed at the time of transmission on the signal demodulated by the wireless communication unit 34 and extracts information contained in the received radio wave. The synchronization of the received spread code string is detected. At this time, in the despreading process, the same spreading code (replica code) as the spreading code used when the transmission wave is generated is used.

  The control unit 38 controls operations of the wireless communication unit 34, the signal processing unit 36, the server communication unit 40, and the like. In addition, the control unit 38 performs operations such as correcting the time so that the time of the clock 44 included in each of the plurality of base stations 12 is synchronized. Specifically, when one of the base stations transmits the time information based on the reference, each other base station receives the time information, and the received time is itself for the propagation time determined from the known inter-base station distance. Correct the clock. As another method, each base station may transmit the received time information to the positioning server 12 to correct the time lag of the clock 44 of each base station 12 on the positioning server 12.

  The reception time measuring unit 42 measures the reception time of the radio wave received by the base station 12 as distance related information, and corresponds to distance related information measuring means. Specifically, for example, the received wave demodulated by the wireless communication unit 34 and the replica code that is the same code as the spreading code used for the spreading process performed when the mobile station 10 transmits the received wave Is calculated by shifting one of them every minute time, and the time when the calculated correlation value reaches a peak is defined as the time of reception of radio waves by the base station 12. Such processing is called synchronization detection.

  The server communication unit 40 performs communication with a positioning server 14 (described later) connected via the wired cable 52 as necessary. For example, the server communication unit 40 transmits a reception time measured to the positioning server 14, or A command for control operation performed wirelessly to the mobile station 10 is received from the positioning server 14.

  The clock 44 is used when the base station 12 determines a radio wave transmission time and reception time, and is used, for example, when it operates at predetermined intervals. Further, the clocks 44 included in each of the base stations 12 are set in advance so that the times coincide with each other.

  Note that the control unit 38 of the base station 12 controls the state in which the base station 12 transmits radio waves and the radio wave in the same manner that the control unit 30 of the mobile station 10 switches between transmitting and receiving radio waves in the mobile station. , And the operation of the wireless communication unit 34, the signal processing unit 36, and the like are switched and controlled in accordance with these states.

  That is, when the base station 12 transmits radio waves, the radio communication unit 34 and the signal processing unit 36 perform the following operation instead of the above-described operation. For example, when the base station 12 transmits radio waves, the signal processing unit 36 transmits information to be transmitted such as a control operation command to the mobile station 10, for example, an M-sequence code or a Gold sequence code used also in GPS. The signal to be transmitted is generated by performing spread processing such as spread spectrum using a spread code such as.

  Further, the radio communication unit 34 modulates the signal generated by the signal processing unit 36 into a format suitable for communication, amplifies a synthesized wave synthesized with a carrier wave of a predetermined frequency by an amplifier, and according to the format of the antenna 32 Convert the unbalanced line to a balanced line using a balun. The radio wave generated in this way is transmitted by the antenna 32. In this way, the base station 12 can transmit in addition to receiving radio waves. On the other hand, since the mobile station 10 can receive radio waves in addition to transmitting radio waves as described above, the base station 12 can control the operation of the mobile station 10 by radio.

  Note that the mobile station 10 and the base station 12 shown in FIGS. 2 and 3 include a power supply unit (not shown). The power supply unit supplies necessary power to each of the mobile station 10 and the base station 12.

  FIG. 4 is a functional block diagram showing an outline of the configuration of the positioning server 14. The positioning server 14 is connected to each base station 12 via a cable 52, and includes a base station communication unit 54, a positioning unit 56, a control unit 60, an output unit 62, and the like. Among these, the base station communication unit 54 performs necessary communication with the server communication unit 40 of the base station 12 connected via the wired cable 52.

  The positioning unit 56 corresponding to the positioning unit that estimates the position of the mobile station 10 includes a time conversion unit 58. The time conversion unit 58 corresponding to the distance related information conversion means is used for one positioning by the mobile station 10 among the reception times of radio waves as distance related information measured by the reception time measurement unit 42 in each of the base stations 12. Therefore, the reception time corresponding to the radio wave transmitted by the transmission other than the reference transmission which is a predetermined single transmission out of the multiple radio wave transmissions is determined by the base station 12 in the multiple radio wave transmissions. Based on the reception interval, it is converted into a reception time corresponding to the reference transmission.

  Specifically, for example, the position of the mobile station 10 and the directivity of the first antenna 21 and the second antenna 22 of the mobile station 10 are as shown in FIG. 5, and the mobile station 10 uses the first antenna 21 to A case will be described in which one transmission is performed and then a second transmission is performed using the second antenna 22. At this time, in each of the first base station 12A to the fourth base station 12D, the reception time measuring unit 42 measures the reception times of the first and second transmission radio waves, and the server communication unit 40 and the wired cable 52 Is transmitted to the positioning server 14. Specifically, the reception time t1A of the first transmission radio wave from the first base station 12A, the reception time t1B of the first transmission radio wave and the reception time t2B of the second transmission radio wave from the second base station 12B, However, while the radio wave reception time t2C from the second transmission is transmitted to the positioning server 14 from the third base station 12C, neither the first radio wave from the mobile station 10 nor the radio wave from the second transmission was received. The reception time is not transmitted from the fourth base station 12D.

  First, the time conversion unit 58 sets one of the first transmission and the second transmission as a reference transmission. Then, a reception time difference, which is a difference between reception times of the radio waves by the first transmission and the second transmission, in the base station that has received both the radio waves by the first transmission and the second transmission is calculated. At this time, when the installation interval between the first antenna 21 and the second antenna 22 in the mobile station 10 has a low influence on the error in view of the wavelength of the radio wave, the installation interval is regarded as 0, the first transmission and The difference between the reception times of the radio waves generated by the second transmission can be regarded as the reception time difference of the radio waves transmitted by the antennas at the same position by the mobile station 10. Then, based on the calculated reception time difference between the first transmission and the second transmission, the reception time of the radio wave by the non-reference transmission is converted into the reception time of the radio wave by the reference transmission. In this manner, the reception time of the radio wave due to the reference transmission is set as the reception time of the radio wave based on the reference transmission.

  Specifically, for example, the time conversion unit 58 first sets the first transmission as a reference transmission. And reception time t1B by the 1st transmission in the 2nd base station 12B which is the base station which received both the 1st transmission which is the standard transmission, and the 2nd transmission which is the other transmission, and reception of the electric wave by the 2nd transmission The difference (t2B-t1B) from time t2B is calculated as the reception interval. Subsequently, the reception time t2C by the third base station 12C, which is the reception time of the radio wave by the second transmission that is not the reference transmission, is converted into the reception time of the radio wave by the first transmission that is the reference transmission based on the transmission time difference. This corresponds to the estimation of the time at which the third base station 12C receives a radio wave from the first transmission when the first transmission is performed in all directions by an antenna having no directivity. Actually, for example, the reception time difference is subtracted from the reception time t2C of the radio wave by the second transmission at the third base station 12C (t2C- (t2B-t1B)), but the converted reference transmission at the third base station 12C It is set as the reception time of the radio wave by a certain first transmission.

FIG. 6 is a diagram conceptually showing how the time conversion unit 58 converts the reception time of radio waves other than the reference transmission to the reception time of radio waves based on the reference transmission. FIG. 6A shows the actual radio wave reception time, where the vertical axis indicates the propagation distance of the radio wave and the horizontal axis indicates the time. The radio waves generated by the first transmission performed at the mobile station 10 at the time T1 are received by the first base station 12A at the time t1A, the second base station 12B at the time t1B, and the second radio wave performed at the time T2. The transmitted radio wave is received by the second base station 12B at time t2B and by the third base station 12C at time t2C. Since the speed of the radio wave is constant at a speed c (2.997 × 10 ⁸ (m / s)), the relationship between the elapsed time from the transmission of the radio wave and the propagation distance is a straight line with an inclination corresponding to the speed c. It is represented by In other words, in FIG. 6A, two parallel straight lines, that is, a straight line 73 representing the propagation of radio waves by the first transmission and a straight line 74 representing the propagation of radio waves by the second transmission are shown. , Point 1A representing reception by the first base station 12A and point 1B representing reception by the second base station 12B, and point 2B and third base station representing reception by the second base station 12B on the straight line 74 Each point 2C representing reception by 12C is shown.

  On the other hand, FIG. 6B shows a state in which the reception time at each base station 12 of the radio wave by the second transmission that is a transmission other than the reference transmission by the time conversion unit 58 is converted into the reception time of the first transmission that is the reference transmission. It is a figure explaining. That is, when the time conversion unit 58 sets the first transmission as the reference transmission, the time conversion unit 58 translates the straight line 74 representing the propagation of the radio wave by the second transmission that is not the reference transmission in the left lateral direction, thereby generating the first reference transmission. It is superimposed on a straight line 73 representing the propagation of radio waves by transmission. At this time, the amount of translation in the horizontal direction is the time corresponding to the reception time difference. As described above, when the influence of the installation interval between the first antenna 21 and the second antenna 22 in the mobile station 10 on the error is low in terms of the wavelength of the radio wave, the straight line 73 and the straight line 74 are overlapped. In this case, the point 1B representing reception of the radio wave by the first transmission by the second base station 12B and the point 2B ′ representing reception of the radio wave by the second transmission by the second base station 12B substantially overlap. A point 2C ′ representing reception by the third base station 12C of the radio wave by the second transmission when the straight line 74 is translated and overlapped with the straight line 73 indicates that the radio wave by the first transmission as the reference transmission is transmitted to the third base. This is a point representing the case where the station 12C was receiving, and the time t2C_shift corresponding to the point 2C ′ is obtained by conversion by the time conversion unit 58. The third base station 12C It becomes the converted value of the received time.

  The positioning unit 56 corresponding to the positioning means includes the reception time of the radio wave transmitted by the reference transmission among the reception times measured by each of the base stations 12, and the reception time of the radio wave by the reference transmission by the time conversion unit 58. The arrival time difference at each base station 12 of the radio wave transmitted from the mobile station 10 is calculated based on the reception time converted into, and the position of the mobile station 10 is calculated based on the arrival time difference.

Specifically, for example, when the movable area 50 is a plane as shown in FIG. 1 and the position on the movable area 50 is specified by the coordinate system as shown in FIG. The position coordinates are (x, y), the position coordinates of the first base station 12A are (x ₁ , y ₁ ), the position coordinates of the second base station 12B are (x ₂ , y ₂ ), and the position of the third base station 12C. The coordinates are (x ₃ , y ₃ ), the distance between the first base station 12A and the mobile station 10 is r ₁ , the distance between the second base station 12B and the mobile station 10 is r ₂ , and the third base station 12C is The distance from the mobile station 10 is r ₃ , the coordinates of the mobile station are (x, y), and the distance error s caused by the time difference between the clocks 31 and 44 of the mobile station 10 and the base station 12 respectively. Then, as shown in FIG.
(X−x ₁ ) ² + (y−y ₁ ) ² = (r ₁ + s) ² ,
(X−x ₂ ) ² + (y−y ₂ ) ² = (r ₂ + s) ² , (1)
(X−x ₃ ) ² + (y−y ₃ ) ² = (r ₃ + s) ²
There is a relationship represented by At this time, for example, the radio wave transmission time information is included in the radio wave transmitted by the mobile station 10 as a spreading code, and the signal processing unit 36 of each base station 12 that has received the information despreads the received radio wave. Thus, the first transmission transmission time T1, which is the reference transmission by the mobile station 10, can be obtained by reading the signal. Therefore, the distance r ₁ between the mobile station 10 and the first base station 12A, the distance r ₂ between the mobile station 10 and the second base station 12B, the distance r ₃ between the mobile station 10 and the second base station 12C, respectively, It is converted into the reception time t1A of the first outgoing radio wave at the first base station 12A, the reception time t1B of the first outgoing radio wave at the second base station 12B, and the reception time of the first outgoing radio wave at the third base station 12C. Using the time t2C_shift and the radio wave velocity c, r ₁ = c × (t1A−T1), r ₂ = c × (t1B−T1), r ₃ = c × (t2C_shift−T1) Calculated. As described above, the clocks 44 included in each of the first base station 12A, the second base station 12B, and the third base station 12C are synchronized, and the error s is common to each base station.

  At this time, there are three variables x, y, and s, and the number of equations is at least three as shown in (1). Therefore, by solving these three equations by, for example, the Newton-Raphson method, x, y That is, the position coordinates (x, y) of the mobile station 10 can be calculated.

  The output unit 62 displays information on the position of the mobile station 10 calculated by the positioning unit 56 in a predetermined method, for example, a display device provided as an output device (not shown) together with the map information as shown in FIG. It outputs by means such as.

  FIG. 8 is a flowchart showing an outline of the control operation of the position detection system of the present invention. First, in a step (hereinafter, “step” is omitted) SA1 corresponding to the antenna switching unit 24 of the mobile station 10, the first antenna 21 is set as an antenna used by the mobile station for transmitting radio waves. Subsequently, in SA2 corresponding to the signal processing unit 28 and the radio communication unit 26 of the mobile station 10, for example, a signal including the transmission time of the radio wave is spread by a predetermined spreading code, and further digital modulation suitable for communication is performed. And is amplified to a predetermined output and transmitted by the first antenna 21 set at SA1. This transmission corresponds to the first transmission.

  In SA3 corresponding to the radio communication unit 34, the signal processing unit 36, and the reception time measurement unit 42 of each base station 12, radio waves transmitted from the mobile station 10 in SA2 are received by each base station 12. The received radio wave is subjected to predetermined demodulation processing and despreading processing, and the radio wave reception time is calculated by the synchronization detection processing. In addition, information contained in the received wave obtained by despreading the received wave and the reception time of the radio wave are transmitted to the positioning server 14 via the wired cable 52.

  In SA4, it is determined whether or not the calculation of the reception time of the radio wave transmitted from the mobile station 10 as the first transmission in SA2 has been performed in two or more base stations 12. When the reception time is calculated in two or more base stations, the determination in this step is affirmed and the subsequent SA5 is executed. On the other hand, when the reception time cannot be calculated in two or more base stations 12, such as when any one of the base stations 12 fails to receive radio waves, the steps after SA2 are executed again.

  In SA5 corresponding to the antenna switching unit 24 of the mobile station 10, the second antenna 22 which is an antenna different from the antenna set in SA1 is set as an antenna used by the mobile station for transmitting radio waves.

  Subsequently, in SA6 corresponding to the signal processing unit 28 and the radio communication unit 26 of the mobile station 10, information including, for example, radio wave transmission time information is spread by a predetermined spreading code as in SA2, and further communicated. Appropriate digital modulation is performed, the signal is amplified to a predetermined output, and transmitted by the second antenna 22 set in SA5. This transmission corresponds to the second transmission.

  In SA7 corresponding to the radio communication unit 34, the signal processing unit 36, and the reception time measurement unit 42 of each base station 12, the radio wave transmitted from the mobile station 10 in SA6 is received in each base station 12, similarly to SA3. Is done. The received radio wave is subjected to predetermined demodulation processing and despreading processing, and radio wave reception time is calculated by the synchronization detection processing. In addition, information contained in the received wave obtained by despreading the received wave and the reception time of the radio wave are transmitted to the positioning server 14 via the wired cable 52.

  In SA8, it is determined whether or not the calculation of the reception time of the radio wave transmitted from the mobile station 10 in SA6 was performed in two or more base stations 12 including one or more base stations 12 that received the first transmission. The When the reception time is calculated in two or more base stations 12 including one or more base stations 12 that have received the first transmission, the determination in this step is affirmed, and the subsequent SA9 is executed. On the other hand, when one of the base stations 12 failed to receive the radio wave, the reception time could not be calculated in two or more base stations 12 including one or more base stations 12 that received the first transmission. In this case, the steps after SA6 are executed again.

  In SA9 corresponding to the time conversion unit 58, one of the first transmission that is the transmission of the radio wave in SA2 and the second transmission that is the transmission of the radio wave in SA6 is set as the reference transmission, and the radio waves other than the reference transmission The reception time at each base station is converted into the reception time of the reference transmission radio wave. For example, when the first transmission is set as the reference transmission, the reception time of each base station that has received the radio wave by the second transmission is converted to the reception time when the first transmission is received.

  In SA10 corresponding to positioning section 56, the reception time at each base station of the first transmission radio wave obtained at SA3, and the base station of the second transmission radio wave obtained at SA7 which is the reference transmission obtained at SA7. The position of the mobile station 10 is calculated based on the reception time of the radio wave by the reference transmission obtained by converting the reception time at SA9.

  According to the above-described embodiment, in the mobile station 10, the wireless communication unit 26 corresponding to the transmission unit and the control unit 30 that controls the wireless communication unit 26 are the first antennas 21 that are a plurality of directional antennas of the mobile station 10. The second antenna 22 is used to transmit radio waves a plurality of times for one positioning, and in the plurality of base stations 12 of three or more, the reception time measuring unit 42 corresponding to the distance related information measuring means The reception time of the radio wave from the mobile station 10 is measured as the distance related information, and in the positioning server 14, the time conversion unit 58 corresponding to the distance related information conversion means is measured by each of the plurality of base stations 12. Out of a reception time, a transmission other than a reference transmission which is a predetermined one out of a plurality of transmissions of radio waves for one positioning by the mobile station 10 The received radio wave reception time is converted into a reference radio wave reception time based on a reception interval in a plurality of radio wave receptions by a base station that has received multiple times, and a positioning unit 56 corresponding to the positioning means Of the reception times measured by each of the plurality of base stations 12, from the reception time of the radio wave transmitted by the reference transmission and the reception time of the radio wave by the reference transmission converted by the time conversion unit 58, In the reference transmission, the arrival time difference of each of the plurality of base stations 12 of the radio wave transmitted from the mobile station 10 is calculated, and the position of the mobile station 10 is calculated based on the arrival time difference. Even if it is the reception time of the radio wave at the base station 12 that has received only the radio wave by, the reception time that is the distance related information after the conversion conversion by the time conversion unit 58 is It can be converted into the reception time of the radio wave in the reference transmission, and it is not necessary for all the base stations 12 to receive a single radio wave transmission by the mobile station 10. There is no need to transmit radio waves at such a high output that the station 12 can receive, and the transmission power of radio waves from the mobile station 10 can be reduced. In addition, the antenna of the mobile station is not omnidirectional, but can have high directivity and high gain, so that transmission power can be reduced.

  Further, according to the above-described embodiment, each of the first antenna 21 and the second antenna 22 that are the plurality of directional antennas of the mobile station 10 has a communication range of at least one of the other directional antennas. Since the base station 12 is installed so as to overlap the communication range, the first antenna 21 and the second antenna can be obtained when any one of the base stations 12 is located in an area where the communication ranges of the first antenna 21 and the second antenna 22 overlap. A plurality of radio waves respectively transmitted by the terminal 22 can be received.

  Further, according to the above-described embodiment, the radio communication unit 26 of the mobile station 10 corresponding to the transmission unit and the control unit 30 that controls the radio communication unit 10 switch the first antenna 21 and the second antenna 22 of the mobile station 10. In the mobile station 10, the base station 12 required for detecting the position of the mobile station only needs to receive one of these multiple times of radio waves. The mobile station 10 does not need to output radio waves at an intensity that can be received by all the base stations 12 necessary for detecting the position of the mobile station 10, and can reduce the transmission power of the radio waves of the mobile station 10.

  In addition, according to the above-described embodiment, the time conversion unit 58 corresponding to the distance related information conversion unit is one of the first antenna 21 and the second antenna 22 among the plurality of base stations 12. In the base station 12 that has received both the first radio wave transmitted from the second radio wave and the second radio wave transmitted from the other antenna, the reception time of the first radio wave and the reception time of the second radio wave The distance-related information can be converted based on the difference in the reception times.

  In addition, according to the above-described embodiment, the radio communication unit 26 of the mobile station 10 corresponding to the transmission unit and the control unit 30 that controls the mobile unit 10 transmit the radio waves at a predetermined transmission interval, The time conversion unit 58 corresponding to the distance related information conversion means calculates the reception time difference based on the transmission time difference which is the predetermined transmission interval, and based on the calculated reception time difference, the reception time of the radio wave at each base station Since the radio wave transmission interval is a predetermined value, the reception time can be easily converted based on the predetermined transmission interval.

  Next, another preferred embodiment of the present invention will be described in detail with reference to the drawings. In the drawings used for the following description, the same reference numerals are given to the portions common to the above-described embodiment, and the description thereof is omitted.

  FIG. 9 is a functional block diagram for explaining an outline of functions of the mobile station 10 in another embodiment of the present invention, and corresponds to FIG. 2 in the first embodiment. As shown in FIG. 9, the mobile station 10 includes a radio communication unit 26, a signal processing unit 28, a control unit 30, a clock 31, a directivity control unit 122, and a plurality of (three in FIG. 9) transmission / reception antenna elements. 120a, 120b, 120c (hereinafter, simply referred to as transmission / reception antenna elements 120 unless otherwise distinguished), and a plurality of (three in FIG. 9) transmission / reception separating sections 124a, 124b corresponding to each of the antenna elements 120, 124c (hereinafter simply referred to as a transmission / reception separating unit 124 unless otherwise specified).

  When the mobile station 10 transmits radio waves, the radio communication unit 26 generates a main carrier wave of a transmission signal, and transmits the generated main carrier wave to a transmission signal (transmission data) generated by a signal processing unit 28 described later. ) To generate a transmission signal. In addition, when the mobile station receives radio waves, the wireless communication unit 26 generates a local signal having a predetermined frequency, and uses the plurality of transmission / reception antenna elements 120 supplied from the directivity control unit 122 described later. Each received signal is downconverted by multiplying each received signal by the local signal, and these are combined to obtain a received signal. A reception signal whose phase and amplitude are controlled by the control unit 30 described later via the directivity control unit 122 is combined by the wireless communication unit 26 to receive a signal including the plurality of transmission / reception antenna elements 120. The reception directivity of the antenna is determined.

  The transmission / reception antenna element 120 transmits a transmission signal modulated by the wireless communication unit 26 and receives a signal transmitted toward the mobile station 10.

  The directivity control unit 122 controls transmission directivity of transmission signals transmitted from the plurality of transmission / reception antenna elements 120 and controls reception directivity of reception signals received by the plurality of transmission / reception antenna elements 120.

  The transmission / reception separating unit 124 corresponds to each of the plurality of transmission / reception antenna elements 120, and supplies the transmission signal supplied from the directivity control unit 122 to each transmission / reception antenna element 120. The received signal is supplied to the directivity control unit 122. As the transmission / reception separating unit, a circulator or a directional coupler is preferably used.

  The signal processing unit 28 generates a transmission signal to be transmitted from the transmission / reception antenna element 120 via the wireless communication unit 26 as in the first embodiment. At this time, the signal is generated by a spreading process using the spreading code.

  In addition, the directivity control unit 122 controls a plurality of (three in FIG. 9) transmission signal phase control units 132a, 132b, and 132c (hereinafter, in particular, control the phase of each transmission signal supplied from the wireless communication unit 26. When there is no distinction, it is simply referred to as a transmission signal phase control unit 132) and a plurality of (three in FIG. 9) transmission signal amplitude control units 134a, 134b, and 134c (hereinafter, when there is no particular distinction). Is simply referred to as a transmission signal amplitude control unit 134), and each of the transmission signals transmitted from the plurality of transmission / reception antenna elements 120 via the transmission signal phase control unit 132 and the transmission signal amplitude control unit 134 is provided. The transmission directivity of the transmission signal is controlled by controlling the phase and amplitude. Also, a plurality (three in FIG. 9) of received signal phase control units 136a, 136b, and 136c that control the phase of each of the received signals supplied from the plurality of transmission / reception separating units 124 (hereinafter, unless otherwise distinguished, simply Reception signal phase control unit 136) and a plurality of (three in FIG. 9) reception signal amplitude control units 138a, 138b, and 138c (hereinafter simply referred to as reception signal amplitude control unless otherwise distinguished). And control the phase and amplitude of each of the received signals received by the plurality of transmission / reception antenna elements 120 via the received signal phase control unit 136 and the received signal amplitude control unit 138. Thus, the reception directivity of the received signal is controlled.

  When the mobile station 10 transmits radio waves, the control unit 30 controls the phase (and amplitude as necessary) of each of the transmission signals transmitted from the plurality of transmission / reception antenna elements 120, and the transmission direction of the transmission signals. The communication range is changed by controlling the characteristics. Specifically, for example, when receiving a command to transmit radio waves to the base station 12 in order to measure the position of the mobile station 10, first, the communication range of the mobile station 10 is, for example, the first antenna communication of FIG. The transmission signal is transmitted so that the transmission directivity is controlled so as to be in the possible area 71, and then the communication range of the mobile station 10 is the second area where the first antenna communication possible area 71 and a part thereof overlap. A transmission signal is transmitted by controlling the transmission directivity so as to switch to the antenna communicable region 72. That is, the control unit 30 controls a phase of each transmission signal through the directivity control unit 122 to change a transmission antenna configured by the plurality of transmission / reception antenna elements 120 to a phased array antenna for transmission (Phased Array Antenna). ) To control. Alternatively, a transmission antenna configured by the plurality of transmission / reception antenna elements 120 is controlled by controlling the phase and amplitude of each transmission signal through the directivity control unit 122 so that the quality of the reception signal is improved. Control as an antenna (Adaptive Array Antenna). That is, the antenna constituted by the plurality of transmission / reception antenna elements 120 is a directional antenna whose directivity can be changed.

  Thus, in the present embodiment, both the first transmission and the second transmission are sequentially transmitted from the antenna constituted by the transmission / reception antenna element 120, and the directivity of the antenna at the time of transmission is They are different from each other.

  In addition, when the mobile station 10 receives radio waves, the control unit 30 controls reception of each of the reception signals received by the plurality of transmission / reception antenna elements 120 by controlling the phase (and amplitude if necessary). Controls reception directivity of signals. That is, by controlling the phase of each reception signal via the directivity control unit 122, the reception antenna constituted by the plurality of transmission / reception antenna elements 120 is controlled as a reception phased array antenna. Alternatively, a receiving antenna configured by the plurality of transmitting / receiving antenna elements 120 is controlled by controlling the phase and amplitude of each received signal through the directivity control unit 122 so as to improve the quality of the received signal. Control as an antenna. For example, the control unit 30 determines the reception directivity of the reception signal so that the combined amount of the reception signal in the wireless communication unit 26 is as large as possible.

  The mobile station 10 includes a CPU, a ROM, a RAM, and the like. That is, the mobile station 10 includes a so-called microcomputer that performs signal processing in accordance with a program stored in advance in the ROM using the temporary storage function of the RAM, and controls the operation of the directivity control unit 122 and the like by the control unit 30 and wireless Control such as modulation / demodulation control by the communication unit 26 and transmission signal generation control by the signal processing unit 28 are performed.

  In the second embodiment, the base station 12 and the positioning server 14 having the same configuration as that of the first embodiment, for example, those shown in the functional block diagrams of FIGS. 3 and 4 are used in the same manner. Is omitted.

  FIG. 10 is a flowchart showing an outline of the control operation in another embodiment of the position detection system of the present invention. First, in steps corresponding to the directivity control unit 122 of the mobile station 10 (hereinafter, “step” is omitted) SB1, the directivity of the antenna when the mobile station 10 is used for transmitting radio waves is controlled. The communication range of the mobile station 10 is determined, for example, as in the first antenna communication possible area 71 of FIG. Subsequently, in the SB2 corresponding to the signal processing unit 28 and the radio communication unit 26 of the mobile station 10, for example, a signal including the transmission time of the radio wave is spread by a predetermined spreading code, and further digital modulation suitable for communication is performed. And is amplified to a predetermined output and transmitted to the communication range set in SB1. This transmission corresponds to the first transmission.

  In SB3 corresponding to the radio communication unit 34, the signal processing unit 36, and the reception time measuring unit 42 of each base station 12, radio waves transmitted from the mobile station 10 in SB2 are received by each base station 12. The received radio wave is subjected to predetermined demodulation processing and despreading processing, and radio wave reception time is calculated by the synchronization detection processing. In addition, information contained in the received wave obtained by despreading the received wave and the reception time of the radio wave are transmitted to the positioning server 14 via the wired cable 52.

  In SB4, it is determined whether the calculation of the reception time of the radio wave transmitted from the mobile station 10 as the first transmission in SB2 has been performed in two or more base stations 12. When the reception time is calculated in two or more base stations, the determination in this step is affirmed and the subsequent SB5 is executed. On the other hand, when the reception time cannot be calculated in two or more base stations 12, such as when any one of the base stations 12 fails to receive radio waves, the steps after SB2 are executed again.

  In SB5 corresponding to the directivity control unit 122 of the mobile station 10, the communication range of the mobile station 10 is changed. That is, for example, the second antenna communicable region 72 of FIG. 5 is set as a new communication range that partially overlaps the communication range of the mobile station 10 set in SB1, and this new communication range is realized. The directivity of the antenna is controlled.

  Subsequently, in the SB 6 corresponding to the signal processing unit 28 and the radio communication unit 26 of the mobile station 10, for example, information including radio wave transmission time information is spread by a predetermined spreading code and further communicated as in SB 2. Appropriate digital modulation is performed, amplified to a predetermined output, and transmitted to the communication range set in SB5. This transmission corresponds to the second transmission.

  In the SB 7 corresponding to the radio communication unit 34, the signal processing unit 36, and the reception time measuring unit 42 of each base station 12, the radio wave transmitted from the mobile station 10 in SB 6 is received in each base station 12, similarly to SB 3. Is done. The received radio wave is subjected to predetermined demodulation processing and despreading processing, and radio wave reception time is calculated by the synchronization detection processing. In addition, information contained in the received wave obtained by despreading the received wave and the reception time of the radio wave are transmitted to the positioning server 14 via the wired cable 52.

  In SB8, it is determined whether or not the calculation of the reception time of the radio wave transmitted from the mobile station 10 in SB6 has been performed in two or more base stations 12 including one or more base stations 12 that have received the first transmission. The When the reception time is calculated in two or more base stations 12 including one or more base stations 12 that have received the first transmission, the determination in this step is affirmed and the following SB9 is executed. On the other hand, when one of the base stations 12 failed to receive the radio wave, the reception time could not be calculated in two or more base stations 12 including one or more base stations 12 that received the first transmission. In this case, the steps after SB6 are executed again.

  In SB9 corresponding to the time conversion unit 58, either the first transmission that is the transmission of the radio wave in SB2 or the second transmission that is the transmission of the radio wave in SB6 is set as the reference transmission, and the radio waves other than the reference transmission The reception time at each base station is converted into the reception time of the reference transmission radio wave. For example, when the first transmission is set as the reference transmission, the reception time of each base station that has received the radio wave by the second transmission is converted to the reception time when the first transmission is received.

  In the SB 10 corresponding to the positioning unit 56, the reception time at each base station of the radio wave by the first transmission which is the reference transmission obtained at SB3, and the base station of the radio wave by the second transmission which is not the reference transmission obtained at SB7 The position of the mobile station 10 is calculated on the basis of the reception time of the radio wave by reference transmission obtained by converting the reception time at SB9.

  According to the above-described embodiment, in the mobile station 10, the transmitting means transmits the radio wave a plurality of times by switching the directivities of the directional antennas whose directivities can be changed to different states. One base station 12 receives the plurality of times of the first transmission and the second transmission, and the other base station 12 required for detecting the position of the mobile station 10 is one of these multiple transmissions. The mobile station 10 does not need to output radio waves at an intensity that can be received by all the base stations 12 necessary for detecting the position of the mobile station 10, and reduces the transmission power of radio waves from the mobile station. be able to.

  In addition, according to the above-described embodiment, each communication range when being transmitted a plurality of times by the directional antenna capable of changing the directivity of the mobile station 10 is the same as that of at least one of other transmissions. Since the directivity of the directional antenna is controlled so as to overlap the communication range, any one of the base stations 12 is positioned in the region where the communication ranges of the plurality of transmissions overlap each other. It is possible to receive a plurality of radio waves transmitted in the transmission.

  As mentioned above, although the Example of this invention was described in detail based on drawing, this invention is applied also in another aspect.

  For example, in the above-described embodiment, the time conversion unit 58 converts the reception time of the radio wave other than the reference transmission into the reception time corresponding to the transmission of the radio wave by the reference transmission, and the positioning means 56 converts each base of the reception time after conversion. The position of the mobile station 10 is calculated based on the time difference in the station 12 (TDOA method), but is not limited to this. For example, the clocks 31 and 44 of each of the mobile station 10 and all the base stations 12 are set in advance. On the premise of this, the positioning means 56 may calculate the position of the mobile station 10 (TOA method) based on the radio wave reception time by the reference transmission in each base station 12 after conversion.

  In the first embodiment described above, the time conversion unit 58 assumes that the installation interval between the first antenna 21 and the second antenna 22 in the mobile station 10 has a low effect on the error as a result of considering the wavelength of the radio wave and the like. However, the present invention is not limited to this, and when there is a base station 12 that receives both the radio wave transmitted by the first antenna 21 and the radio wave transmitted by the second antenna 22, The radio wave propagation distance between the base station 12 and the radio wave propagation distance between the second antenna 22 and the base station 12 may be different in consideration of the installation interval between the first antenna 21 and the second antenna 22. Good.

  Further, in the above-described embodiment, the time conversion unit 58 is the first in the second base station 12B that is the base station that has received both the first transmission that is the reference transmission and the second transmission that is the other transmission. The difference (t2B-t1B) between the reception time t1B by the transmission and the reception time t2B of the radio wave by the second transmission is calculated as the reception time difference, and based on this, the reception time corresponding to the transmission other than the reference transmission is converted. Not limited to. For example, when the transmission interval at which the mobile station 10 performs the first transmission and the second transmission is a predetermined value that is known in advance, the time conversion unit 58 obtains the known predetermined value in advance to obtain this known value. The reception time of the radio wave by the second transmission may be converted based on the predetermined value. That is, in the above-described embodiment, the time conversion unit 58 has translated the straight line 74 corresponding to the second transmission which is not the reference transmission in FIG. 7 to the left by the reception time difference (t2B−t1B) of the second base station 12B. However, if the time conversion unit 58 has in advance the value of the transmission time difference (T2−T1) by the mobile station 10, this transmission time difference is left instead of the reception time difference (t2B−t1B) of the second base station 12B. The same effect can be obtained even if the movement is parallel. In this way, even when there is no base station 12 that has received both the reference transmission and the transmission other than the reference transmission, the time conversion unit 58 uses the reception time corresponding to the transmission other than the reference transmission as a reference. It can be converted into a reception time corresponding to the transmission.

  When the first transmission and the second transmission are switched at a predetermined interval in this way, preferably, the radio waves transmitted in each of the first transmission and the second transmission are based on the first transmission. The code | symbol for identifying whether it is based on a 2nd transmission may be added. In this way, the base station 12 can easily identify whether the received radio wave is due to the first transmission or the second transmission.

  In addition, preferably, when the time conversion unit 58 uses the transmission time difference of the mobile station 10 as described above, the time of the clock 31 of the mobile station 10 and the time of the clock 44 of the base station 12 are synchronized. For example, the time difference between the clock 31 of the mobile station 10 and the clock of the base station 12 and the clock speed ratio are measured in advance, and the mobile station 10 You may correct | amend the time of the timepiece 31 which this has based on such information. In this way, an accurate transmission time difference can be obtained even when the mobile station 10 does not have a highly accurate timepiece.

  In the first embodiment, the case where the mobile station 10 includes the first antenna 21 and the second antenna 22 that are two directional antennas has been described. However, the mobile station 10 includes three or more directional antennas. Even if it has, it is applicable similarly. Specifically, for example, in the flowchart of FIG. 8, steps SA5 to SA8 are repeated by (number of antennas-1).

  In the first embodiment, the first antenna 21 and the second antenna 22 are each a planar patch antenna having directivity. However, the first antenna 21 and the second antenna 22 are not limited to this. A plurality of array antennas may be installed with different directivities, or a plurality of dipole antennas may be installed with an angle.

  Further, in the above-described embodiment, the case where there is one mobile station 10 has been described. However, even when there are a plurality of mobile stations 10, for example, by using different spreading codes for each mobile station 10, for example, Applicable.

  In the second embodiment described above, the number of antenna elements 120 is three, but is not limited thereto. Further, for example, an antenna such as a dipole antenna may be used as the antenna element 120. In this case, when the mobile station 10 transmits a radio wave, the antenna element 120 is used to transmit a radio wave using a directional array antenna, while when receiving a radio wave, one of the antenna elements 120 is used. Radio waves can also be received using an antenna.

It is a figure showing the outline | summary of the position estimation system of this invention. It is a functional block diagram showing the outline | summary of the function of a mobile station. It is a functional block diagram showing the outline | summary of the function of a base station. It is a functional block diagram showing the outline | summary of the function of a positioning server. It is a figure explaining each communicable range of the 1st antenna and 2nd antenna which a mobile station has. It is a figure explaining the procedure of conversion of the reception time by a distance related information conversion means (time conversion part). It is a figure explaining the estimation of the position of the mobile station by a positioning means (positioning part). It is a flowchart explaining the outline | summary of the control action of the position estimation system of this invention. It is a functional block diagram showing the outline | summary of the function of the mobile station in the position estimation system in another Example of this invention. It is a flowchart explaining the outline | summary of the control action of the position estimation system in another Example of this invention.

Explanation of symbols

10: Mobile station 12: Base station 14: Positioning server 21: First antenna (directional antenna)
22: Second antenna (directional antenna)
24: Antenna switching unit 26: Wireless communication unit (transmitting means)
31: Clock 34: Wireless communication unit (reception means)
42: Reception time measuring unit (distance related information measuring means)
44: Clock 50: Moveable area 56: Positioning unit (positioning means)
58: Time conversion unit (distance related information conversion means)
71: First antenna communicable area 72: Second antenna communicable area

Claims (6)

A mobile station having a transmission means for transmitting radio waves, and a movable mobile station;
Receiving means for receiving radio waves transmitted by the mobile station, and distance-related information measuring means for measuring distance-related information that is information related to the distance from the mobile station based on the received radio waves, A plurality of base stations having clocks fixed in known positions and synchronized with each other;
A positioning server that calculates a position of the mobile station based on distance-related information measured by each of the plurality of base stations,
The transmitting means transmits a plurality of times of radio waves having mutually different communication ranges for one positioning,
The plurality of base stations includes three or more base stations,
The distance related information is a reception time of radio waves from the mobile station received by the receiving means of each base station,
The positioning server
Of the distance-related information measured by each of the plurality of base stations, other than the reference transmission which is a predetermined one out of a plurality of transmissions of radio waves for one positioning by the mobile station Distance that converts distance-related information corresponding to radio waves transmitted by transmission into distance-related information corresponding to the reference transmission based on reception intervals in reception of multiple times of radio waves by a base station that has received multiple times Related information conversion means,
Among the distance related information measured by each of the plurality of base stations, the distance related information corresponding to the radio wave transmitted by the reference transmission, and the distance related information converted by the distance related information conversion means, Positioning means for calculating a difference in arrival time of each of the plurality of base stations of a radio wave transmitted from the mobile station in a reference transmission, and calculating a position of the mobile station based on the difference in arrival time. Position detection system. The transmission means performs transmission of radio waves a plurality of times such that each communication range in the plurality of radio wave transmissions overlaps at least one communication range of communication ranges in other transmissions. The position detection system according to claim 1. The mobile station has a plurality of directional antennas having different directivities,
The position detection system according to claim 1, wherein the transmitting unit transmits the radio wave a plurality of times by switching a plurality of directional antennas of the mobile station. The mobile station has a directional antenna capable of changing directivity,
The position detection system according to claim 1, wherein the transmitting unit transmits the radio wave a plurality of times with different directivities of the directional antennas for one positioning. The distance-related information conversion means is distance-related information corresponding to the radio wave generated by the first transmission in the base station that has received the radio waves generated by two or more transmissions of the plurality of radio wave transmissions among the plurality of base stations. The distance-related information is converted based on a reception time difference between a certain reception time and a reception time that is distance-related information corresponding to the radio wave transmitted by the second transmission. The described position detection system. The transmitting means performs the transmission of the radio wave at a predetermined transmission interval,
The distance-related information conversion unit calculates the reception time difference based on a transmission time difference that is the predetermined transmission interval, and converts the distance-related information based on the calculated reception time difference. The position detection system according to any one of 1 to 4.

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