JP2009052982A - Mobile station positioning system and mobile station positioning method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a mobile station positioning system capable of correcting a time between mobile stations in a short time. <P>SOLUTION: A reception interval calculation part 82 (SA1) calculates a reception interval between two diffusion codes in a diffusion code train transmitted once from a reference base station 11 and received by each ordinary base station 12. A clock speed ratio calculation part 54 (SA2) calculates a clock speed ratio between each ordinary base station 12 and the reference base station 11 based on the reception interval in each ordinary base station 12 and a transmission interval between the two diffusion codes by the reference base station 11. A timepiece deviation calculation part (SA3) calculates a time deviation of a timepiece in each ordinary base station 12 to a timepiece 44 in the reference base station 11. A reception time correction part 58 (SA4) corrects a reception time of a radio wave from a mobile station 10 in each ordinary base station 12 to a time based on the timepiece in the reference base station 11. A positioning part 60 (SA5) positions the mobile station 10 by using the corrected reception time. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a position estimation method and a positioning system in which a plurality of base stations receive radio waves transmitted from a mobile station, and the position of the mobile station is estimated based on the time difference of reception times at each of the base stations, which is the reception result In particular, the present invention relates to a technique capable of positioning a mobile station with high accuracy by correcting a reception time based on a clock speed ratio between the plurality of base stations.

  A positioning system and a positioning method have been proposed in which radio waves transmitted by a mobile station are received by a plurality of base stations, and the position of the mobile station is detected based on the time difference between the reception times of the radio waves at each of the plurality of base stations. ing.

  In such a positioning system or positioning method, it is necessary to calculate the reception time difference of radio waves between a plurality of base stations, and therefore it is necessary to set the clocks of the plurality of base stations to a common time. There is.

  On the other hand, instead of setting the clock of each of the plurality of base stations, the trend of the clock of each of the plurality of base stations is detected in advance, that is, the clock ratio of the clock, the time lag, etc. A technique has been proposed in which a reception time of a radio wave from a mobile station detected by a clock of each base station is corrected based on a tendency of the clock, as grasped by calculation. For example, this is the technique described in Patent Document 1.

Japanese Patent No. 3801123

  According to the description of Patent Document 1, a plurality of other base stations measure the reception time of a signal transmitted from a single base station a plurality of times using each clock, and each base station is based on the reception time and the like. A technique is disclosed in which the clock speed ratio of a station is estimated and the position of the mobile station is detected by correcting the reception time at each base station of radio waves from the mobile station based on the estimated clock speed ratio.

  However, according to the technique described in Patent Document 1, in order to calculate the clock speed ratio, a signal is transmitted a plurality of times from one base station to another base station. For this reason, the time required for positioning may be increased.

  The present invention has been made against the background of the above circumstances, and its object is to transmit a signal from a reference base station, which is one of the plurality of base stations, to another base station. Mobile station positioning system and mobile station capable of calculating clock speed ratio of clocks possessed by each of a plurality of base stations and estimating mobile station position accurately in a short time by performing once It is to provide a positioning method.

  The gist of the invention according to claim 1 for solving this problem is that (a) a plurality of base stations receive radio waves transmitted from a mobile station, and each of the plurality of base stations receives radio waves A mobile station positioning system that estimates a position of the mobile station based on a time difference between reception times and positions of the plurality of base stations, and (b) a spread including two spreading codes among the plurality of base stations (C) at least one reference base station that transmits the code sequence once, and (c) two or more ordinary base stations that receive the spread code sequence transmitted from the reference base station among the plurality of base stations, d) Detecting the reception time of each of the two spreading codes included in the spreading code string received by each of the normal base stations, and calculating the reception interval of the two spreading codes based on the detected reception time A reception interval calculating means; (e) Based on the reception interval of the two spread codes calculated by the reception interval calculation means in each of the normal base stations, and the transmission interval when the reference base station transmits the two spread codes, the normal A clock speed ratio calculating means for calculating a ratio of clock speeds between each of the base stations and the reference base station; and (f) a transmission time of the spreading code string by the reference base station and the spreading by each of the ordinary base stations. Clock deviation for calculating the time difference of each clock of the normal base station with respect to the clock of the reference base station, based on the reception time of the code string and the distance between the reference base station and the normal base station that are known in advance And (g) a reception time at which each of the ordinary base stations receives the radio wave from the mobile station calculated based on a clock possessed by each of the ordinary base stations. The ratio of the clock speed between each of the normal base stations calculated by the clock speed ratio calculation means and the reference base station, and the normal base station with respect to the clock of the reference base station calculated by the clock deviation calculation means. (H) a mobile station in the normal base station corrected by the reception time correcting means, which corrects the time based on the clock of the reference base station based on the time lag of each clock. Positioning means for estimating the position of the mobile station based on the reception time of the radio wave from the reception time of the radio wave from the mobile station in the reference base station, and the position information of the normal base station and the reference base station; It is characterized by having.

  Preferably, the gist of the invention according to claim 2 is that transmission of the spreading code string by the reference base station is performed prior to transmission of radio waves for positioning by the mobile station. And

Further, the gist of the invention according to claim 3 is that: (a) The reception time of the radio wave is detected by performing synchronization detection processing of the spread code included in the received radio wave as the spread code is received. An online reception time detection means for detecting the reception time of the radio wave with a more precise accuracy than the online reception time detection means in (b) the synchronization detection process of the spread code contained in the received radio wave. And (c) the reception interval calculation means determines an offline detection execution section for executing the offline reception time detection means based on a detection result by the online reception time detection means, and the offline detection execution section Detecting the reception time of the two spread codes in the offline reception time detection means,
It is characterized by.

  The gist of the invention according to claim 4 is characterized in that the reference base station transmits the same or different spreading codes as the two spreading codes.

  Further, the gist of the invention according to claim 5 is characterized in that the reference base station transmits a spreading code string including the two spreading codes using a spreading code different for each reference base station. To do.

  The gist of the invention according to claim 6 is that: (a) a plurality of base stations receive radio waves transmitted from a mobile station, and a time difference between reception times of the radio waves respectively received by the plurality of base stations; A mobile station positioning method for estimating a position of the mobile station based on positions of the plurality of base stations, wherein (b) at least one of the plurality of base stations includes two spreading codes (C) at least two of the plurality of base stations are ordinary base stations that receive the spreading code string transmitted from the reference base station, and (d) ) The reception time of each of the two spreading codes included in the spreading code sequence received by each of the normal base stations is detected, and the reception interval of the two spreading codes is calculated based on the detected reception time. A reception interval calculation step; (e) Based on the reception interval for each of the two spread codes in each of the normal base stations calculated by the reception interval calculation step, and the transmission interval when the reference base station transmits the two spread codes A clock speed ratio calculating step of calculating a clock speed ratio between each of the normal base stations and the reference base station; (f) a transmission time of the spreading code string by the reference base station; and Based on the reception time of the spread code string by each and the distance between the reference base station and the ordinary base station that are known in advance, the time difference of each clock of the ordinary base station with respect to the clock of the reference base station A clock deviation calculating step of calculating; (g) each of the normal base stations from the mobile station calculated based on the clock of each of the normal base stations; A reception time at which a wave is received, a ratio of a clock speed between each of the normal base stations calculated by the clock speed ratio calculating step and the reference base station, and the reference base station calculated by the clock deviation calculating step A reception time correction step of correcting the time based on the clock of the reference base station based on the time difference of each clock of the ordinary base station with respect to the clock of (h), and (h) correction by the reception time correction step Based on the reception time of the radio wave from the mobile station at the received base station, the reception time of the radio wave from the mobile station at the reference base station, and the location information of the normal base station and the reference base station. And a positioning step for estimating the position.

  The gist of the invention according to claim 7 is characterized in that the transmission of the spread code string by the reference base station is performed prior to the transmission of radio waves for positioning by the mobile station.

  The gist of the invention according to claim 8 is that: (a) the reception time of the radio wave is detected by performing synchronization detection processing of the spread code included in the received radio wave as the spread code is received. An online reception time detection step, and (b) an offline reception time detection step of detecting the reception time of the radio wave with a more detailed accuracy than that of the online reception time detection step. And (c) the reception interval calculation step determines an offline detection execution section in which the offline reception time detection step is executed based on a detection result of the online reception time detection step, and the offline detection execution section And detecting the reception times of the two spread codes by the offline reception time detecting step.

  The gist of the invention according to claim 9 is characterized in that the reference base station transmits the same or different spreading codes as the two spreading codes.

  The gist of the invention according to claim 10 is characterized in that the reference base station transmits a spreading code string including the two spreading codes using a spreading code different for each reference base station. To do.

  According to the mobile station positioning system according to claim 1 or the mobile station positioning method according to claim 6, the reference base station transmits once by the reception interval detection means or the reception interval detection step, and the two or more normal The reception time for each of the two spreading codes included in the spreading code string including the two spreading codes received by the base station is detected, and the reception interval of the two spreading codes is determined based on the detected reception time. Calculated by the clock speed ratio calculating means or the clock speed ratio calculating step, at the interval between the reception times of the two spreading codes in the respective ordinary base stations detected by the reception interval detecting means or the reception interval detecting step, respectively. Based on a certain reception interval and a transmission interval when the reference base station transmits the two spreading codes, the normal base station The ratio of the clock speed between each and the reference base station is calculated, and the time difference calculation means or the time difference calculation step calculates the transmission time of the spread code string by the reference base station and the normal base station respectively. Based on the reception time of the spread code string and the distance between the reference base station and the normal base station, which are known in advance, a deviation of each clock of the normal base station from the clock of the reference base station is calculated, and the reception By the time correction means or the reception time correction step, the reception time at which the radio base station receives the radio wave calculated based on the clock of the normal base station by each of the normal base stations is the clock speed. Of the reference base station based on the ratio of the time of each clock of the normal base station with respect to the clock of the reference base station The time of reception of radio waves from a mobile station in a normal base station corrected by the positioning means or the positioning step and corrected by the reception time correcting means or the reception time correcting step, and the reference base station Since the position of the mobile station is estimated based on the reception time of the radio wave from the mobile station and the position information of the normal base station and the reference base station, the transmission of one spread code string by the reference base station Since the clock speed ratio between each clock of the normal base station and the clock of the reference base station is calculated based on the above, positioning with high accuracy is possible in a short time.

  According to the mobile station positioning system according to claim 2 or the mobile station positioning method according to claim 7, the transmission of the spreading code string by the reference base station is prior to the transmission of radio waves for positioning by the mobile station. Therefore, when radio waves from a mobile station are received at the plurality of base stations, the reception time can be corrected promptly using the clock speed ratio, and the time required for positioning can be shortened. .

  Further, according to the mobile station positioning system according to claim 3 or the mobile station positioning method according to claim 8, in the reception interval calculation means or the reception interval calculation step, the radio wave received along with the reception of the spread code is received. The online reception time detection means or the online reception time detection based on the detection result of the online reception time detection means or the online reception time detection step for detecting the reception time of the radio wave by performing synchronization detection processing of the included spread code The offline reception time detecting means for detecting the reception time of the radio wave with a more detailed accuracy than the process or the offline detection execution section for executing the offline reception time detection process is determined, and the two spread codes are received in the offline detection execution section. By the offline reception time detection means Therefore, the reception time of the two spread codes is performed by the offline reception time detection means or the offline reception time detection process capable of detecting with higher accuracy than the online reception time detection means or the online reception time detection process. Can do. In addition, the offline reception time detection means or the offline reception time detection process that requires more power is executed based on the detection result of the online reception time detection means or the online reception time detection process. This can be done in the section, and power consumption can be reduced.

  Further, according to the mobile station positioning system according to claim 4 or the mobile station positioning method according to claim 9, the reference base station transmits the same or different spreading codes as the two spreading codes. When the two spreading codes are the same, the configuration for detecting the synchronization of the spreading codes can be simplified. When the two spreading codes are different from each other, the normal base station can identify each of the two received spreading codes, and can reliably calculate the reception interval.

  Further, according to the mobile station positioning system according to claim 5 or the mobile station positioning method according to claim 10, the reference base station includes the two spreading codes using different spreading codes for each reference base station. Since the spreading code string is transmitted, a plurality of reference base stations can exist at the same time, and redundancy can be provided when the reference base station fails. In addition, since the plurality of ordinary base stations have a function as a second reference base station, it is possible to increase the area where positioning is possible in a superimposed manner.

  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 positioning possible region 5 composed of a square with a side 30 (m) is provided as a region where a mobile station 10 provided in an arbitrary shape on a plane can move. Further, in the positioning possible region 5, one reference base station 11 as a base station having a function of performing wireless communication with a mobile station 10 described later, and a first ordinary base station 12A as three ordinary base stations, A second ordinary base station 12B and a third ordinary base station 12C are provided. Note that the number of reference base stations and ordinary base stations is one or more for the reference base station and two or more for the ordinary base stations, respectively, due to their functions. In order to perform positioning of the mobile station, as will be described later, when calculating the position of the mobile station 10 moving on the plane using the propagation time of the radio wave, at least three base stations are required. Therefore, the base station is arranged so that at least the mobile station can communicate with the three base stations at any point in the positioning possible region. Note that the position of the mobile station can be calculated more accurately as the number of base stations increases. In FIG. 1, one reference base station 11 and one ordinary base station 12A to 12C are arranged at each of the four corners of a square positioning possible region 5, and there are four base stations. Satisfy the requirements for positioning. In addition, the mobile station 10 is capable of positioning within the positioning possible region 5. 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 each base station by being connected by, for example, a wired cable 52, and based on the radio waves transmitted by the mobile station 10 and received by the base station 12, the positioning server 14 is provided. The position of the base station 10 in the possible area is calculated. In this specification, the individual ordinary base stations 12A to 12C are expressed as ordinary base stations 12 unless otherwise distinguished. Further, when the reference base station 11 and the ordinary base station 12 are not distinguished, they are denoted as base stations 11 and 12.

  At this time, in the positioning possible region 5, the x axis and the y axis are defined as shown in FIG. 2 for convenience, and the coordinates of the points on the positioning possible region 5 are defined based on these axes. That is, the reference base station 11 is on the coordinates (0, 0), the first base station 12A is on the coordinates (0, 30), the second base station 12B is on the coordinates (30, 30), and the third base station. 12C are arranged on coordinates (30, 0).

  FIG. 3 is a functional block diagram showing an outline of functions of the mobile station 10. The mobile station 10 includes an antenna 20 through which the mobile station transmits and receives radio waves, a radio communication unit 26, a signal processing unit 28, a control unit 30, a clock 31, a transmission code generation unit 29, and the like.

  The wireless communication unit 26 performs wireless communication with the mobile station 10 and is a transmission unit that transmits radio waves when the mobile station 10 transmits radio waves. Specifically, a spread code string generated by a transmission code generation unit 29 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 a balun. For example, the unbalanced line is converted into a balanced line. The radio wave generated in this way is transmitted by the antenna 20. The wireless communication unit 26 is a receiving unit that receives a control signal transmitted from the base station. Specifically, the radio communication unit 26 performs demodulation processing such as digital demodulation corresponding to the communication method on the radio wave received by the antenna 20.

  The signal processing unit 28 extracts a control command transmitted from the base station by processing the signal demodulated by the wireless communication unit 26. This control command is transmitted to the control unit 30 to be described later and used for control determination of the control unit.

  The transmission code generation unit 29 generates a spread code sequence transmitted from the mobile station to the base stations 11 and 12, a spread code generated by a spread code generation unit 32 (to be described later), and a warning code generated by a warning code generation unit 33. Generate based on and. The transmission code generated by the transmission code generation unit 29 is transmitted wirelessly by the wireless communication unit 26. The transmission code generation unit 29 generates a spread code generation unit 32 that generates a spread code that is used for detection of reception time by a detailed reception time detection unit 80 that will be described later, and a transmission code prior to the spread code that is used for detection of this reception time. A notice code generation unit 33 for generating a notice code to be generated.

  Among these, the spread code generation unit 32 generates a spread code used for detection of the reception time by the detailed reception time detection unit 80 of the base stations 11 and 12 described later. Further, the notice code generation unit 33 generates a notice code that is transmitted a predetermined time before the spread code generated by the spread code generation unit 32. This predetermined time is, for example, a difference in transmission time between the transmission completion time when transmitting the notice code and the transmission completion time of the spread code generated by the spread code generation unit 32. For example, the predetermined time is determined in advance by the base station 11 , 12 and a value known between the mobile station 10 is used. That is, the spread code string generated by the transmission code generation unit 29 includes at least the notice code and the spread code transmitted after the predetermined time.

  The clock 31 is used when the mobile station 10 determines the time of transmission of radio waves, and is used when the mobile station 10 operates at predetermined intervals, for example.

  The control unit 30 controls operations of the wireless communication unit 26, the signal processing unit 28, the transmission code generation unit 29, 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, the radio wave is transmitted with a predetermined output.

  The control unit 30 controls the operation of the wireless communication unit 26, the signal processing unit 28, and the like to be switched depending on whether the mobile station 10 transmits radio waves or receives radio waves. Further, when receiving a spread code transmission request for positioning based on a control command from the base station, the control unit 30 transmits a spread code to the wireless communication unit 26 at a predetermined time to the transmission code generation unit 32. To control

  FIG. 4 is a functional block diagram showing an outline of the functions of the base stations 11 and 12. The base stations 11 and 12 include an antenna 35, a radio communication unit 34, a signal processing unit 36, a control unit 38, a clock 44, and a transmission code generation unit 72, which respectively include the antenna 20 and the radio communication included in the mobile station 10 described above. Unit 26, signal processing unit 28, control unit 30, clock 31, transmission code generation unit 29, and base stations 11 and 12 have these antenna 20, radio communication unit 34, signal processing unit 36, In addition to the control unit 38, the clock 44, and the transmission code generation unit 72, a real-time reception time detection unit 78, a detailed reception time detection unit 80, a reception interval calculation unit 82, a control signal generation unit 37, and the like are included.

  That is, the wireless communication unit 34 performs wireless communication between the base stations 11 and 12 and is a receiving unit that receives radio waves when the base stations 11 and 12 receive radio waves. Specifically, the radio communication unit 34 performs demodulation processing such as digital demodulation corresponding to the communication method on the radio wave received by the antenna 35.

  Further, the signal processing unit 36 extracts a control command transmitted from the base station by processing the signal demodulated by the wireless communication unit 34. This control command is transmitted to the control unit 38, which will be described later, and used for control determination of the control unit.

  The control signal generator 37 generates a control signal for searching for an empty channel in a reference base station, which will be described later, and generates a response signal for searching for an empty channel in a normal base station. Further, a signal for requesting the mobile station to transmit a positioning signal is generated. The control signal generated by the control signal generation unit 37 is transmitted to the wireless communication unit 34 and wirelessly transmitted by the antenna 35.

  Note that the control unit 38 of the base station 12 switches the state where the control unit 30 of the mobile station 10 transmits and receives radio waves in the mobile station, and the control unit 38 of the base station 12 transmits the radio waves. And the state of receiving radio waves can be switched, and the operations of the wireless communication unit 34, the signal processing unit 36, and the like are switched and controlled in accordance with these states.

  Further, the radio communication unit 34 modulates the signal generated by the control signal generation unit 37 into a format suitable for communication, amplifies a synthesized wave synthesized with a carrier wave of a predetermined frequency by an amplifier, and unbalances by a balun or the like Convert lines to balanced lines. The radio wave generated in this way is transmitted by the antenna 35. 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 and receive radio waves as described above, the base station 12 can control the operation of the mobile station 10 by radio.

  When the base stations 11 and 12 operate as the reference base station 11, the transmission code generation unit 72 generates a spread code string transmitted from the reference base station 11 to the normal base station 12 by a spread code generation unit 74 described later. It generates based on the generated spreading code and the warning code generated by the warning code generator 76. Further, when transmitting the spread code string, the transmission code generation unit 72 transmits information about the transmission completion time of the second spread code to the positioning server 14 via the server communication unit 40 described later. The transmission code generation unit 72 generates a spread code generation unit 74 that generates a spread code used for detection of reception time by a detailed reception time detection unit 80 described later, and a transmission code prior to the spread code used for detection of this reception time. A notice code generation unit 76 for generating a notice code to be generated.

  Among these, the spread code generation unit 74 is a spread code used for detection of the reception time by the detailed reception time detection unit 80 described later, and includes two spread codes of a first spread code and a second spread code. A spreading code string is generated. The notice code generation unit 76 generates a notice code that is transmitted for a predetermined time before the spread code including the two spread codes generated by the spread code generation unit 74. The predetermined time is determined in advance by the positioning system, and the control unit 38 controls the spread code generating unit 74 and the notice code generating unit 76 based on the information.

  As described above, since the base stations 11 and 12 have a common configuration, the base station that operates as the reference base station 11 can operate as the normal base station 12 instead of or in addition to the operation. Is possible. In this way, when the base station that has been operating as the reference base station 11 breaks down, the base station that has been operating as the normal base station 12 until then can newly operate as the reference base station 11. The positioning system 8 can have redundancy.

  FIG. 6 is a diagram for explaining an example of a spread code string generated by the transmission code generation unit 72. In FIG. 6, the time axis representing the passage of time t is set in the direction from right to left in the figure. In other words, the left side represents a spreading code that is generated later as it goes to the left. In FIG. 6, the first spreading code is represented by PN1, the second spreading code is represented by PN2, and the warning code is represented by PN3.

  First, the notice code PN3 generated by the notice code generator 76 is transmitted a predetermined time p before the transmission of the first spread code. At this time, the transmission completion time of the notice code PN3 is Taq1 '. Thereafter, after the elapse of the predetermined time p, the first spreading code PN1 generated by the spreading code generation unit 74 is transmitted, and then the second spreading code PN2 generated by the spreading code generation unit 74 is changed to the PN1. Will be sent continuously. At this time, the transmission completion time of the first spreading code PN1 is tim_b0_trfend_b0, and the transmission completion time of the second spreading code PN2 is tim_b0_trend_b0. The transmission time difference tim_b0_trend_b0-tim_b0_trend_b0 between the first spreading code PN1 and the second spreading code PN2 is Ts. The transmission completion time of the first spreading code PN1 is expressed as tim_b0_trfend_b0 = Taq1 '+ p, using the transmission completion time Taq1' of the notice code PN3 and the transmission time difference p.

  Further, in the code string shown in FIG. 6, a spread code PN0 that is neither one of these is transmitted except for the first spread code PN1, the second spread code PN2, and the notice code PN3. In this case, when this code string is received, it is sufficient that the cross-correlation with the replica code when performing synchronization detection on the receiving side is sufficiently smaller than the autocorrelation. Therefore, if the cross-correlation with the replica code is sufficiently smaller than the autocorrelation, it is not necessary that all PN0s are the same spreading code. At this time, the predetermined time p is determined by the number of codes PN0 transmitted between the notice code PN3 and the first spreading code PN1. For example, the same spreading code is used as the first spreading code PN1, the second spreading code PN2, and the notice code PN3.

  Returning to FIG. 4, the real-time reception time detection unit 78 measures the reception time of the radio waves received by the base stations 11 and 12. Specifically, for example, the correlation value between the received wave demodulated by the wireless communication unit 34 and the replica code that is the same code as the spreading code included in the received wave is used, and the received wave is changed every minute. The time at which the calculated autocorrelation value reaches a peak is taken as the radio wave reception time by the base station 12. Such processing is called synchronization detection. The real-time reception time detection unit 78 combines, for example, a delay circuit that delays the reception wave every minute time, a matched filter that calculates a correlation value between the reception wave delayed by the delay circuit and the replica code, and the like. Is realized. For example, the real-time reception time detection unit 78 detects the reception time at the base stations 11 and 12 of the warning code transmitted from the mobile station 10 for positioning. It is also used for detecting the reception time of the transmitted notice code. As described above, when the same spreading code is used as the first spreading code PN1, the second spreading code PN2, and the warning code PN3, the same spreading code is the same code. It is sufficient to detect synchronization only for one replica code.

  At this time, the real-time reception time detection unit 78 performs so-called real-time synchronization detection that immediately detects synchronization with the reception of the radio wave by the wireless communication unit 34, that is, the reception signal of the wireless communication unit 34. In other words, synchronization detection processing must be performed at a speed that matches the speed of the spreading code to be received. For example, when a spreading code is received sequentially, if a code is received, the synchronization detection of that code is performed by Must be completed before receiving. The real-time reception time detection unit 78 corresponds to an online reception time detection means or an online reception time detection process. By the way, as described above, the synchronization detection is performed by using the correlation value between the received wave and the replica code that is the same code as the spreading code used when transmitting the received wave, and using the received wave for a short time. The time at which the peak of the correlation value appears is taken as the reception time, but the accuracy of this synchronization detection is how fine the minute time is when the received signal is shifted every minute time. It depends on whether it can be set. That is, the length of the minute time and the number of calculations required for synchronization detection are inversely proportional. Therefore, in the case of performing synchronization detection in real time as described above, there is a restriction on the time during which the calculation can be performed, that is, the number of calculations, and thus there is a limit to the accuracy when performing synchronization detection.

  The detailed reception time detection unit 80 measures the reception time of radio waves received by the base stations 11 and 12 with higher accuracy than the real time reception time detection unit 78 performs. Specifically, for example, the received wave demodulated by the wireless communication unit 34 is temporarily stored in a storage device (not shown), and the replica code is the same code as the spread code included in the stored received wave Is calculated by shifting the received wave every minute time, and the time when the calculated autocorrelation value reaches its peak is defined as the time when the base station 12 receives the radio wave. At this time, by setting the minute time to be shorter than the minute time in the synchronous detection of the real-time reception time detection unit 78, highly accurate detection is possible. In addition to the storage device (not shown), the detailed reception time detection unit 80 is delayed by, for example, a delay circuit that delays the reception wave every minute time, or the delay circuit, as in the real time reception time detection unit 78 described above. This is realized by combining a matched filter for calculating a correlation value between the received wave and the replica code. The detailed reception time detection unit 80 corresponds to an offline reception time detection means or an offline reception time detection step.

  The detailed reception time detection unit 80 can be executed only in a predetermined time interval. That is, the base stations 11 and 12 are set to always detect the reception time by the real-time reception time detector 78, and in particular, to detect the reception time with high accuracy by the detailed reception time detector 80. Only in the time interval, in addition to or instead of the detection of the reception time by the real-time reception time detector 78, the detailed reception time detector 80 may detect the reception time with high accuracy. In this way, the detailed reception time detection unit 80 requires more power for calculation than the real-time reception time detection unit 78, and therefore the detailed reception time detection unit 80 is highly efficient only in a predetermined time interval. By accurately detecting the reception time, it is possible to save power in the base stations 11 and 12.

  For example, the reception time difference between the reception time of the first spreading code and the reception time of the second spreading code at each ordinary base station 12 calculated by the reception interval calculation unit 82 described later is calculated with higher accuracy. It is desirable. Therefore, the detailed reception time detection unit 80 detects the reception times of the first spreading code and the second spreading code by detecting the reception time with high accuracy. For example, the detailed reception time detection unit 80 determines the reception time of each of the first spreading code and the second spreading code based on a notice code transmitted prior to the first spreading code in the reference base station 11. Detection is performed by detecting the reception time with high accuracy.

  FIG. 7 is a diagram illustrating a received signal when the normal base station 12 receives a code string including the notice code, the first spreading code, and the second spreading code transmitted from the reference base station 11. is there. In FIG. 7, the time axis representing the passage of time t is set in the direction from the right to the left in the figure as in FIG. Here, in the normal base station 12, when the real-time reception time detection unit 78 detects reception of the warning code PN3, the detailed reception time detection unit 80 calculates the warning code and the first spreading code from the reception completion time Taq1. A time interval in which the width before and after the margin m is centered around the elapse of the transmission time difference p is set as a detection target time interval by the detailed reception time detection unit 80. That is, highly accurate detection of the reception time is executed in Taq1 + p−m ≦ t ≦ Taq1 + p + m. This detection target time section corresponds to the offline detection execution section. Here, the margin m is the time required for receiving the first spreading code and the second spreading code, the time difference between the clock 44 of the reference base station 11 and the clocks 44 of all the normal base stations 12, A value that is set so that the reception time of the highly accurate time can be detected by the detailed reception time detection unit 80 for both the first spreading code and the second spreading code in consideration of the speed ratio and the like. It is.

  Returning to FIG. 4, the reception interval calculation unit 82 calculates the reception interval at the normal base station 12 of the first spreading code and the second spreading code detected by the detailed reception time detection unit 80. That is, in the detailed reception time detection unit 80, the reception completion time of the first spreading code and the reception completion time of the second spreading code are detected by synchronization detection, and the difference between them is calculated. Thus, the reception interval between the first spreading code and the second spreading code is calculated. That is, the reception interval calculation means 82 or the detailed reception time detection unit 80 realizes a reception interval detection means or a reception interval detection step.

  The control unit 38 also controls operations of the wireless communication unit 34, the signal processing unit 36, the server communication unit 40, and the like.

  The server communication unit 40 performs communication with a positioning server 14 (described later) connected via a wired cable 52 as necessary. For example, the details of radio waves received from the mobile station 10 by the base stations 11 and 12 are detailed. The reception time detected by the reception time detector 80, the reception interval between the first spreading code and the second spreading code received by the normal base station 12 from the reference base station 11, the second of the reference base station 11 A value such as a transmission end time of the spread code and a transmission interval between the first spread code and the second spread code transmitted by the transmission code generation unit 72 is transmitted to the positioning server 14 or designated by the server. The interval between the first spread code and the second spread code in the spread code string generated by the transmission code generation unit 72, or a command for the base station 12 or a control action to be performed wirelessly for the mobile station 10. The effect actuation of such received from the positioning server 14.

  The clock 44 is used when the base station 12 determines the transmission time and reception time of radio waves, and is used, for example, when the operation is performed at predetermined intervals.

  In the mobile station 10 and the base station 12 shown in FIGS. 2 and 3, functional blocks corresponding to functions not directly involved in the control operation in the present invention are omitted. For example, the mobile station 10 and the base station 12 include a power source (not shown). This power supply supplies necessary power to each of the mobile station 10, the base station, and the positioning server 14.

  FIG. 5 is a functional block diagram showing an outline of the functions 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 53, a clock speed ratio calculation unit 54, a clock deviation calculation unit 56, a reception time correction unit 58, a positioning unit 60, and a positioning. A result output unit 62 and the like are included. Among these, the base station communication unit 53 is necessary communication with the server communication unit 40 of the base stations 11 and 12 connected via the wired cable 52, for example, transmission / reception of measurement data, base station 12 and movement A command for controlling the operation of the station 10 is transmitted.

  The clock speed ratio calculation unit 54 receives the reception interval between the first spreading code and the second spreading code calculated by the reception interval calculation unit 82 of each ordinary base station 12 and the transmission of the reference base station 11. Based on the transmission interval between the first spreading code and the second spreading code generated by the code generation unit 72 and transmitted by the wireless communication unit 34 or the like, the clock 44 of each of the ordinary base stations 12 has. And a clock speed ratio that is a ratio of the speed of the reference base station 11 to the clock 44. The clock speed ratio calculation unit 54 corresponds to a clock speed ratio calculation means or a clock speed ratio calculation step.

Specifically, the clock speed ratio rera_b0bi is received by the detailed reception time detector 80 based on the clock 44 of the ordinary base station 12 of the second spreading code transmitted from the reference base station 11 to the ordinary base station 12. Tim_bi_rvlend_b0bi which is the time, reception time tim_bi_rvfend_b0bi by the detailed reception time detector 80 based on the clock 44 of the normal base station 12 of the first spreading code, and the first by the transmission code generator 72 of the reference base station 11 Is obtained by the following equation (1) using a code period Ts which is a transmission interval between the spread code and the second spread code.
rera_b0bi = (tim_bi_rvlend_b0bi-tim_bi_rvfend_b0bi) / Ts (1)

  The clock deviation calculation unit 56 calculates a clock deviation that is a deviation of the time of each clock 44 of the normal base station 12 with respect to the time of the clock 44 of the reference base station 11. This clock deviation is the advance or delay of the time with respect to the time of the clock 44 of the reference base station 11. For example, the transmission time of the radio wave transmitted from the reference base station 11 and the radio wave at the ordinary base station 12 that received the radio wave. And the propagation time of the radio wave calculated from a known distance between the reference base station 11 and the ordinary base station 12. This clock deviation calculating unit corresponds to a clock deviation calculating means or a clock deviation calculating step.

Specifically, for example, the clock deviation te_aq_b0bi is a transmission measured by the clock 44 of the reference base station 11 by measuring the completion of transmission of the second spreading code transmitted from the wireless communication unit 34 of the reference base station 11 to the normal base station 12. A time tim_b0_trlend_b0 which is a completion time, a reception completion time tim_bi_rvlend_b0bi obtained by measuring the reception time of the second spreading code at the ordinary base station 12 using the clock 44 of the ordinary base station 12 by the detailed reception time detector 80, and a system in advance 8, the propagation time calculated by dividing the radio wave velocity c (= 2.997 × 10 ⁸ (m / s)) by the distance (for example, 30 m) between the reference base station 11 and the ordinary base station 12 known from FIG. It is obtained by the following equation (2) using tau0_i.
te_aq_b0bi = (tim_bi_rvlend_b0bi-tim_b0_trlend_b0)-tau0_i (2)
That is, using the second spreading code as an example, the apparent radio wave propagation time calculated from the transmission completion time at the reference base station 11 and the reception completion time at the normal base station 12, and the actual reference base station 11 and the normal The true radio wave propagation time calculated based on the distance to the base station 12 is compared, and if there is a difference between these values, the difference is between the clock 44 of the reference base station 11 and the clock 44 of the ordinary base station 12. This is a time lag.

  The reception time correction unit 58 is based on the clock 44 of each ordinary base station 12 by the real-time reception time detection unit 78 in each ordinary base station 12 when a radio wave transmitted from the mobile station 10 is received by each ordinary base station 12. The clock speed ratio between the clock 44 of the reference base station 11 and the clock 44 of each ordinary base station 12 calculated by the clock speed ratio calculator 54, and the clock deviation calculator 56. Based on the time difference between the clock 44 of the reference base station 11 and the clock 44 of each of the ordinary base stations 12 calculated in step S2, the time is corrected to the time of the clock 44 of the reference base station 11. This reception time correction unit 58 corresponds to reception time correction means or a reception time correction step.

Specifically, for example, the reception time correction unit 58 corrects the reception time according to the following procedure. First, when the radio wave transmitted from the mobile station 10 is received at the reference base station 11 and the ordinary base station 12, the reception time detected based on the respective clocks 44 by the respective real-time reception time detection units 78 is It is assumed that the reference base station 11 is tim_b0_rvend_m1b0 and the normal base station 12 is tim_bi_rvend_m1bi. At this time, when tim_bi_rvend_m1bi, which is the reception time detected based on each clock 44 by the real-time reception time detection unit 78 of the ordinary base station 12, is converted into a time based on the clock 44 of the reference base station 11, The reception time TOA_m1bi of the ordinary base station 12 is expressed by the following equation (3).
TOA_M1bi = tim_bi_rvend_m1bi-(tim_bi_rvend_m1b0-tim_b0_rvend_m1b0)… (3)
Here, tim_bi_rvend_m1b0, which is the first term on the right side of Equation (3), is a time obtained by converting the reception time tim_b0_rvend_m1b0 of the spread code transmitted from the mobile station 10 into the clock 44 of the ordinary base station 12. That is, the second term enclosed in parentheses on the right side is the time lag between the clock 44 of the reference base station 11 and the clock 44 of the ordinary base station 12 when the reference base station 11 receives the radio wave from the mobile station 10. It is a term to represent.

Further, tim_bi_rvend_m1b0 in the equation (3) is expressed by the following equation (4) using the clock speed ratio rera_b0bi calculated by the clock speed ratio calculation unit 54.
tim_b1_rvend_m1b0 = tim_bi_aq
+ (tim_b0_rvend_m1b0-tim_b0_aq) × rera_b0bi… (4)
Here, tim_bi_aq which is the first term on the right side of the equation (4) is the time in the clock 44 of the ordinary base station 12 when the time lag is calculated by the time lag calculating unit 56. Further, tim_b0_aq is the time in the clock 44 of the reference base station 11 when the time lag is calculated by the clock lag calculation unit 56, and tim_b0_rvend_m1b0 is the reception time of the spread code transmitted from the mobile station 10 in the reference base station 11. And rera_b0bi is the clock speed ratio calculated by the clock speed ratio calculator 54. That is, the second term on the right side of the equation (4) indicates the time from when the time difference is calculated by the time difference calculation unit 56 in the reference base station 11 until reception of the radio wave from the mobile station 10. By multiplying the time measured by the clock 44 of the base station 11 by the clock speed ratio between the clock 44 of the reference base station 11 and the clock 44 of the ordinary base station 12, the time corresponds to the clock 44 of the ordinary base station 12. It becomes the value converted into the time to do.

Further, tim_bi_aq in the equation (4) is obtained by using the time difference te_aq_b0bi between the clock 44 of the reference base station 11 and the clock 44 of the ordinary base station 12 calculated by the clock deviation calculation unit 56 as follows: ).
tim_bi_aq = tim_b0_aq + te_aq_b0bi (5)
Here, as described above, tim_b0_aq is the time in the clock 44 of the reference base station 11 when the time shift is calculated by the clock shift calculation unit 56. As described above, the time shift calculation unit 56 is the reference base station. 11 is the transmission completion time (transmission time) of the second spreading code in 11,
tim_b0_aq = tim_b0_trlend_b0 (6)
It is. When the equation (5) is transformed using the equation (6) and the equation (2) representing the time shift te_aq_b0bi,
tim_bi_aq = tim_b0_trlend_b0 + (tim_bi_rvlend_b0bi-tim_b0_trlend_b0)-tau0_i
= tim_bi_rvlend_b0bi-tau0_i (7)
It becomes. As described above, the reception time correction unit 58 receives the tim_bi_rvend_m1bi that is the reception time detected based on the respective clocks 44 by the detailed reception time detection unit 80 of the normal base station 12 based on the clocks 44 of the reference base station 11. Can be converted to time TOA_m1bi.

  The reception time correction unit 58 repeats the above-described procedure as many times as the number of the normal base stations 12, so that the reception times detected for all the normal base stations 12 by the detailed reception time detection unit 80 based on the respective clocks 44. Tim_bi_rvend_m1bi can be converted into a reception time TOA_m1bi based on the clock 44 of the reference base station 11.

In this embodiment, the clock speed ratio is not considered for the propagation time of the radio wave from the reference base station 11 to the ordinary base station 12. In reality, the propagation time is about several nano (10 ^-9 ) seconds, and therefore an error caused by the clock speed ratio during propagation is negligibly small. This is because the radio wave propagation time may not take into account the clock speed ratio. Of course, this can also be taken into account.

  Returning to FIG. 5, the positioning unit 60 that calculates the position of the mobile station, that is, performs positioning, is corrected by the reception time correction unit 58 to correspond to the time of the clock 44 of the reference base station 11. The positioning of the mobile station 10 is determined based on the reception time of the radio wave from the mobile station 10 in the base station 11, the reception time of the radio wave from the mobile station 10 in the reference base station 11, and the information on the position of each known base station. Do.

  At this time, the radio wave transmitted from the mobile station 10 includes the spread code string generated by the transmission code generation unit 29 as described above. This spreading code string is composed of a notice code generated by the notice code generator 33 and a spread code generated by the spread code generator 32 that is transmitted after a predetermined time elapses after the notice code is transmitted. Therefore, the reception time of the radio wave from the mobile station 10 in each ordinary base station 12 is first determined by the same procedure as the calculation of the reception time of the radio wave from the reference base station 11 used in the clock speed ratio calculation unit 54 and the like. The real time reception time detection unit 78 receives the notice code transmitted from the mobile station 10 and determines a detection target time interval by the detailed reception time detection unit 80. In this interval, the detailed reception time detection unit 80 determines the mobile station. By receiving the spread code transmitted from 10, it is possible to accurately detect the reception time of the radio wave from the mobile station.

  Further, the reception time of the radio wave from the mobile station 10 in each ordinary base station 12 detected in this way is corrected by the reception time correction unit 58 so as to correspond to the time of the clock 44 of the reference base station 11. Therefore, even if the time of the clock 44 of each base station 11 and 12 is not actually synchronized, by using the corrected reception time, it is as if the clock 44 of each base station 11 and 12 is a reference base station. 11 clocks 44 can be handled as if they were synchronized. The positioning unit 60 corresponds to positioning means or a positioning process.

For example, in FIG. 8, when a radio wave is transmitted from the mobile station 10 at time t ₀ , the detailed reception time detection units are respectively provided in the reference base station 11, the first ordinary base station 12A, and the second ordinary base station 12B which are three base stations. 80, it is assumed that radio waves are received from the mobile station at tim_b0_rvend_m1b0, tim_b1_rvend_m1b1, and tim_b2_rvend_m1b2. Among these, the reception time detected by the clock 44 of the ordinary base station 12 in the ordinary base station 12 is corrected to the time based on the time of the clock 44 of the reference base station 11 by the reception time correction unit 58. . That is, the reception times tim_b1_rvend_m1b1 and tim_b2_rvend_m1b2 of radio waves from the mobile station 10 in the first ordinary base station 12A and the second ordinary base station 12B are corrected to TOA_m1b1 and TOA_M1b2, respectively. Note that the reception time of the radio wave from the mobile station 10 at the reference base station 11 is not corrected by the reception time correction unit 58. The time is written as TOA_m1b0. That is, TOA_m1b0 = tim_b0_rvend_m1b0.

を例えばニュートンラフソン法などにより解くことで、移動局１０の位置（ｘ，ｙ）が算出される。なお、前記式（８）が式（９）のように変形されると、移動局１０による電波の発信時刻ｔ₀および移動局１０の時計３１と基準基地局１１の時計４４の時刻ずれΔｔに伴う距離ｓは式（９）から消去され、解の算出にあたりこれらの値を得る必要がない、いわゆるＴＤＯＡ(Time Difference of Arrival)方式による測位となる。なお、図８においては、１つの基準基地局１１および２つの普通基地局である３つの基地局１１、１２からなる場合について説明したが、４以上の基地局１１、１２が移動局１０からの電波を受信した場合も同様であるので、説明を省略する。また３次元測位の場合においても未知数が一つ増えるだけであるので説明を省略する。 At this time, the actual radio wave propagation time is determined by the difference between the reception time measured by the base stations 11 and 12 and the transmission time measured by the clock 31 of the mobile station 10. And the time difference between the clock 31 of the mobile station 10 is taken into consideration. As described above, in the present invention, the reception time of the radio wave from the mobile station 10 in each base station 11, 12 is corrected to the reception time corresponding to the time of the clock 44 of the reference base station 11. Thus, by using the corrected reception time, the clock 44 of each base station 11, 12 can be regarded as being synchronized with the clock 44 of the reference base station 11. Accordingly, if the time difference between the clock 44 of the reference base station 11 and the clock 31 of the mobile station 10 is Δt, the propagation time of the radio wave from the mobile station 10 to the reference base station 11 is (TOA_m1b0−t ₀ + Δt) movement. The propagation time of radio waves from the station 10 to the first ordinary base station 12A is (TOA_m1b1−t ₀ + Δt), and the propagation time of radio waves from the mobile station 10 to the second ordinary base station 12B is (TOA_m1b2−t ₀ + Δt). . As mentioned above, the position of each base station 12 in FIG. 8 is a known, coordinates indicating the position, reference base station 11 is (x _0, y _0), the first ordinary base station 12A is (x ₁ , Y ₁ ), the second ordinary base station 12B is (x ₂ , y ₂ ), and the coordinates indicating the position of the mobile station 10 that is the object of positioning are (x, y). m / s)
(X−x ₀ ) ² + (y−y ₀ ) ² = (c × (TOA_m1b0−t ₀ ) + s) ² ,
(X−x ₁ ) ² + (y−y ₁ ) ² = (c × (TOA_m1b1−t ₀ ) + s) ² , (8)
(X−x ₂ ) ² + (y−y ₂ ) ² = (c × (TOA_m1b3−t ₀ ) + s) ²
It becomes. However, s = Δt × c. Further, r ₁ , r ₂ , and r ₃ in FIG. 8 are r ₀ = c × (TOA_m1b0−t ₀ ), r ₁ = c × (TOA_m1b1−t ₀ ), and r ₂ = c × (TOA_m1b2−t _{0), respectively.} ). Here, an equation derived by taking the square roots of both sides of the second equation and the third equation of the equation (8), and further subtracting the square root of both sides of the first equation from both sides,

For example, by the Newton-Raphson method, the position (x, y) of the mobile station 10 is calculated. When equation (8) is transformed into equation (9), radio wave transmission time t _{0 by} mobile station 10 and time difference Δt between clock 31 of mobile station 10 and clock 44 of reference base station 11 The accompanying distance s is eliminated from the equation (9), and positioning is performed by a so-called TDOA (Time Difference of Arrival) method in which it is not necessary to obtain these values when calculating the solution. In addition, in FIG. 8, although the case where it consists of three base stations 11 and 12 which are one reference base station 11 and two normal base stations was demonstrated, four or more base stations 11 and 12 from mobile station 10 The same applies to the case of receiving a radio wave, and the description thereof is omitted. Also, in the case of three-dimensional positioning, the number of unknowns is only increased by one, so the description is omitted.

  Returning to FIG. 5, the control unit 56 controls operations of the base station communication unit 54, the positioning unit 60, and the like. The output unit 62 outputs information about the position of the mobile station 10 calculated by the positioning unit 60 by a predetermined method, for example, by displaying the information on a display device provided as an output device (not shown).

  FIG. 9 is a flowchart for explaining the outline of the control operation of the mobile station positioning system 8 in the present embodiment. First, in step SA1 (hereinafter, “step” is omitted), the first spreading code and the second spreading code transmitted from the reference base station 11 at predetermined intervals are received by the respective ordinary base stations 12. A reception interval calculation routine for calculating the reception interval at the time of execution is executed.

  FIG. 10 is a flowchart for explaining an example of this reception interval calculation routine. First, in SB1, whether there is a channel that can be used when the code sequence is transmitted from the positioning server 14 to the reference base station 11 by radio from the reference base station 11 to the normal base station 12, that is, whether there is an empty channel. The reference base station 11 searches for this empty channel. Then, in the subsequent SB2, whether or not there is an empty channel is transmitted to the positioning server 14 by the reference base station 11 that has performed the search. At this time, if there is an empty channel, the determination of this step is affirmed and the subsequent SB3 and subsequent steps are executed. On the other hand, if there is no empty channel, the determination of this step is denied and SB1 is detected until an empty channel is found. The search continues.

  In SB3, the positioning server 14 instructs each ordinary base station 12 to receive a spreading code string transmitted from the reference base station 11. In the subsequent SB4, a response indicating that the reception of the spread code string has been started is sent to the positioning server 14 from each ordinary base station 12 that has received the SB3 command. At this time, if there is a response from all the normal base stations 12 that reception standby has been started, the determination in this step is affirmed, and the subsequent SB5 and subsequent steps are executed. On the other hand, if there is no response from any of the ordinary base stations 12 that the standby for reception has been started, the determination at this step is denied and the reception command is transmitted again at SB3.

  In SB5, the positioning server 14 transmits to the reference base station 11 a command for wirelessly transmitting the spread code string using the empty channel searched and found in SB1. Then, in the SB 6 corresponding to the transmission code generation unit 72, the signal processing unit 36, the wireless communication unit 34, etc. of the reference base station 11, the warning code PN3 and the first notification code PN3 are received by the reference base station 11 that has received the SB5 command. The spreading code string generated so that the spreading code PN1 is transmitted at a predetermined interval p and the second spreading code PN2 is transmitted following the first spreading code PN1 is transmitted by radio.

  In SB 7 corresponding to the radio communication unit 34, signal processing unit 36, real-time reception time detection unit 78, etc. of the ordinary base station 12, it is determined whether or not the spreading code string transmitted from the reference base station 11 is received in SB 6. Is done. When the spread code string is received by all the normal base stations 12, the determination in this step is affirmed and the subsequent SB8 is executed. On the other hand, if the reception of the spread code string has failed in any of the ordinary base stations 12, the determination in this step is denied, and SB5 to SB7 are executed again, so that all the ordinary base stations 12 The process is repeated until a spreading code string transmitted from the station 11 is received.

  In SB8 corresponding to the detailed reception time detection unit 80, the reception interval calculation unit 82, etc., the first spreading code and the second code included in the radio wave transmitted from the reference base station 11 in SB6 and received in SB7. The reception time of each spreading code is detected, and the reception interval is calculated. At this time, in the detection of the reception time, for example, the received wave is once stored in a storage device (not shown), and the received wave read from the storage device is set to a value smaller than that in the case of performing synchronous detection in real time. The correlation value with the replica signal is calculated using a delay circuit that delays for each delay time and a matched filter, and the reception completion time when the peak of the correlation value is detected is used as a reception time. This step is executed, for example, at Taq1 + pm ≦ t ≦ Taq1 + p + m, which is a predetermined time interval calculated in advance from time Taq1 when reception of the notice code is detected in SB7. The reception interval calculated in this way is transmitted to the positioning server 14, and this routine ends.

  Returning to FIG. 9, in SA2 corresponding to the clock speed ratio calculation unit 54, the reception interval between the first spreading code PN1 and the second spreading code PN2 in each ordinary base station 12 calculated in SA1 ( tim_bi_rvend_b0bi-tim_bi_rvfend_b0bi) and the transmission interval Ts between the first spreading code PN1 and the second spreading code PN2 transmitted from the reference base station 11 in SB6, A clock speed ratio rera_b0bi with each clock 44 of the normal base station 12 is calculated.

  In SA3 corresponding to the clock shift calculation unit 56, for example, the reference is performed in the process of calculating the reception interval between the first spreading code and the second spreading code in each ordinary base station 12 in SA1. The transmission time tim_bi_rvfend_b0bi of the second spreading code by the base station 11, the reception time tim_bi_rvend_b0bi of the second spreading code in each ordinary base station 12, and the reference base station 11 and the ordinary base station 12 that are known in advance. Based on the true radio wave propagation time tau0_i calculated based on the distance, the time difference te_aq_b0bi between the time of the clock 44 of the reference base station 11 and the time of the clock 44 of each of the normal base stations 12 is each normal. Calculated for base station 12.

  In SA4 corresponding to the reception time correction unit 58, the reception time calculated with reference to the clock 44 of each normal base station 12 of the spread code received in each normal base station 12 is used as the reference base station 11. A correction formula for correcting the time based on the clock 44 is calculated. That is, the propagation of the true radio wave calculated based on the clock speed ratio calculated in SA2, the time lag calculated in SA3, or the distance between the reference base station 11 and the normal base station 12 that are known in advance. Using the time or the like, the equations (3) to (7) are determined.

  In SA5 corresponding to the positioning unit 60, a positioning routine for calculating the position of the mobile station 10 is executed.

  FIG. 11 is a diagram for explaining an example of this positioning routine. First, in SC1, similarly to SB1 and SB2 in the reception interval calculation routine of FIG. 10, when transmitting a code string from the mobile station 10 to each of the base stations 11 and 12 from the positioning server 14 to the reference base station 11, by radio. A command for searching whether there is a usable channel, that is, whether there is a free channel is issued, and the reference base station 11 searches for this free channel. In the subsequent SC2, the presence or absence of an empty channel is transmitted to the positioning server 14 by the reference base station 11 that has performed the search. At this time, if there is an empty channel, the determination of this step is affirmed and the subsequent SC3 and subsequent steps are executed. On the other hand, if there is no empty channel, the determination of this step is denied and SC1 is detected until an empty channel is found. The search continues.

  In SC3, the positioning server 14 instructs each ordinary base station 12 to receive a spreading code transmitted from the mobile station 10. In the subsequent SC4, a response to the effect that the standby of reception of the spreading code is started is sent to the positioning server 14 from each of the base stations 11 and 12 that has received the command of SC3. At this time, if there is a response indicating that the standby of reception has started from all the base stations 11 and 12, the determination in this step is affirmed and the subsequent SC5 and subsequent steps are executed. On the other hand, if there is no response from any of the ordinary base stations 12 that the reception standby has been started, the determination at this step is denied and the reception command is transmitted again at SC3.

  In SC5, an instruction for the mobile station 10 to wirelessly transmit the spread code string to the mobile station 10 from the positioning server 14 using the empty channel searched and found in SC1 is, for example, the reference base station 11 Sent through. In other words, the reference base station 11 that has received a command from the positioning server 14 wirelessly transmits a command for the mobile station 10 to wirelessly transmit the spreading code sequence using the empty channel searched and found in the SC1. The In the SC 6 corresponding to the signal processing unit 28, the radio communication unit 26, the control unit 30, etc. of the mobile station 10, a spreading code for positioning of the mobile station 10 is transmitted by the mobile station 10 that has received the command of SC 5. Is done. The spreading code transmitted at this time may be any spreading code as long as it is a known code for which a replica code is prepared in the base stations 11 and 12 to be received in advance. For example, the notice code PN3 and the first spreading code described above are used. If the spreading code is different from PN1, the second spreading code PN2, and any of the spreading codes PN0 transmitted between these spreading codes, the base stations 11 and 12 that have received them transmit from the mobile station 10. It is possible to distinguish the spread code from the notice code PN3, the first spread code PN1, and the second spread code PN2 transmitted from the reference base station 11.

  In SC7 corresponding to the radio communication unit 34, the signal processing unit 36, the real-time reception time detection unit 78, the detailed reception time detection unit 80, and the like of the base stations 11 and 12, the mobile station 10 transmitted from the mobile station 10 in SC6. It is determined whether or not a spreading code for positioning has been received. When the spread code string is received in all the base stations 11 and 12, the determination in this step is affirmed and the subsequent SC8 is executed. On the other hand, if the reception of the spreading code string has failed in any of the ordinary base stations 12, the determination in this step is denied, and SC5 to SC7 are executed again, and all the base stations 11 and 12 are moved. The process is repeated until a spreading code transmitted from the station 10 is received.

  In SC8 corresponding to the real-time synchronization detection unit 78, the detailed reception time detection unit 80, and the like, the positioning of the mobile station 10 included in the radio wave transmitted from the mobile station 10 in SC6 and received by the base stations 11 and 12 in SC7. The reception time of the spreading code for is detected by synchronization detection. Then, the calculated reception time is transmitted to the positioning server 14.

  In SC9 corresponding to the reception time correction unit 58, the reception time at the ordinary base station 12 among the reception times at the base stations 11 and 12 detected at the SC8 and transmitted to the positioning server 14 is calculated at SA4. The time is corrected based on the clock of the reference base station 11 according to the correction formula.

  In the SC 10 corresponding to the positioning unit 60, the reception time at the reference base station 11 among the reception times at the base stations 11 and 12 detected and transmitted to the positioning server 14 at the SC 8, and the reference base station 11 at SC 9. Positioning of the mobile station 10 is performed based on the reception time at the ordinary base station 12 corrected to the time based on the clock and information on the positions of the reference base station 11 and the ordinary base station 12.

  According to the above-described embodiment, the reference base station transmits one time and two or more ordinary base stations 12 receive by the reception interval detection unit 82 (SA1) corresponding to the reception interval detection means or the reception interval detection step. A reception time is detected for each of the two spreading codes included in the spreading code string including the first spreading code and the second spreading code, which are two spreading codes, and the 2 based on the detected receiving time. The reception intervals of two spread codes are calculated, and each ordinary base detected by the reception interval calculation unit 82 by the clock rate ratio calculation means 54 or the clock rate ratio calculation unit 54 (SA2) corresponding to the clock rate ratio calculation step is calculated. Based on the reception interval of the two spreading codes at the station 12 and the transmission interval when the reference base station 11 transmits the two spreading codes, the normal base station 2 and the reference base station 11 clock speed ratios are calculated, and the clock deviation calculation unit 56 (SA3) corresponding to the clock deviation calculation means or the clock deviation calculation step calculates the spread code by the reference base station 11. Transmission completion time of the second spreading code in the sequence, reception completion time of the second spreading code in the spreading code sequence by each of the ordinary base stations 12, and the reference base station and the ordinary base station that are known in advance Is calculated based on the distance from the clock 44 of the reference base station 11 to the reception time correction unit 58 corresponding to the reception time correction means or the reception time correction step. According to (SA4), the radio wave from the mobile station 10 calculated based on the clock 44 of each of the normal base stations 12 is transmitted by each of the normal base stations 12. The received reception time is corrected to a time based on the clock 44 of the reference base station 11 based on the ratio of the clock speed and the time difference of each clock of the normal base station with respect to the clock of the reference base station. The reception time of the radio wave from the mobile station 10 at the normal base station 12 corrected by the reception time correction unit 58 by the positioning unit 60 (SA5) corresponding to the positioning means or the positioning process, and the movement at the reference base station 11 Since the position of the mobile station 10 is estimated based on the reception time of the radio wave from the station 10 and the position information of the ordinary base station 12 and the reference base station 11, the transmission of the spread code string by the reference base station 11 once The clock speed ratio between each clock 44 of the normal base station 12 and the clock 44 of the reference base station 11 is calculated based on the above, and the time required for positioning is shortened.

  Further, according to the above-described embodiment, the transmission of the spread code string by the reference base station 11 is performed prior to the transmission of radio waves for positioning by the mobile station 10, so that the mobile stations in the plurality of base stations 11, 12 When a radio wave from 10 is received, the reception time can be corrected immediately using the clock speed ratio, and the time required for positioning is shortened.

  In addition, according to the above-described embodiment, the real-time reception time detection unit 78 that detects the reception time of the radio wave by performing synchronization detection processing of the spread code included in the received radio wave when the spread code is received. And a detailed reception time detection unit 80 for detecting the reception time of the radio wave with a finer accuracy than the real time reception time detection unit 78 for detecting synchronization of a spread code included in the received radio wave, and the real time reception The detailed reception time detection unit 80 is executed based on the detection result of the reception time of the warning code PN3 by the time detection unit 78 and the transmission time difference p between the predetermined warning code PN3 and the first spread code PN1. The time interval (Taq1 + pm ≦ t ≦ Taq1 + p + m) to be detected by the detailed reception time detector 80 is determined, and the detailed reception time detector 80 Since the reception time of the two spreading codes in the detection target time interval is detected by the detailed reception time detector 80, the reception times of the two spreading codes of the first spreading code PN1 and the second spreading code PN2 are This can be performed by the detailed reception time detection unit 80 capable of detecting with higher accuracy than the real time reception time detection unit 78. Further, the detailed reception time detection unit 80 that determines the execution of the detailed reception time detection unit 80 that requires more power based on the detection result of the reception time of the warning sign PN3 by the real-time reception time detection unit. This can be performed in the detection target time interval, and the power consumption can be reduced.

  Further, according to the above-described embodiment, the reference base station 11 transmits the first spreading code PN1 and the second spreading code PN2 which are mutually the same or different spreading codes as the two spreading codes, respectively. When the two spreading codes are the same, the configuration for detecting the synchronization of the spreading codes can be simplified. When the two spreading codes are different from each other, the normal base station can identify each of the two received spreading codes, and can reliably calculate the reception interval.

  Subsequently, another embodiment of the present invention will be described. In the following description, portions common to the embodiments are denoted by the same reference numerals and description thereof is omitted.

  FIG. 12 is a diagram for explaining another example of the mobile station positioning system 8 according to the present invention and corresponds to FIG. In the present embodiment, as shown in FIG. 12, in the positioning possible region 5 including the region 5A and the region 5B, the first reference base station 11A is provided as the reference base station, and the first normal base station is used as the normal base station. Seven of 12A thru | or 7th normal base station 12G are provided. As shown in FIG. 12, although the first reference base station 11A can communicate with the first ordinary base station 12A to the fourth ordinary base station 12D by radio, the fifth ordinary base station 12E to Communication with the seventh ordinary base station 12G is impossible. Further, in the mobile station positioning system 8, there are no base stations 11 and 12 that can wirelessly communicate with all the base stations 11 and 12 other than the mobile station positioning system 8.

  As described above, the first reference base station 11A cannot communicate with the fifth ordinary base station 12E to the seventh ordinary base station 12G by radio, and therefore the first reference base station 11A does not perform the spreading code. Even if the sequence is transmitted, the fifth ordinary base station 12E to the seventh ordinary base station 12G cannot receive the spreading code sequence. Therefore, the clock speed ratio calculation unit 54 calculates the clock speed ratio between the normal base stations 12E to 5G and the first reference base station 11A and the clock deviation calculation unit. 56, the time difference cannot be calculated, and even when the radio wave from the mobile station 10 is received by the fifth ordinary base station 12E to the seventh ordinary base station 12G based on their clocks 44, The time correction unit 58 cannot correct the reception time to a time based on the time of the clock 44 of the first reference base station 11A.

  By the way, as shown in FIG. 12, the fourth ordinary base station 12D to the seventh ordinary base station 12G can communicate with each other wirelessly. That is, if any one of the fourth ordinary base station 12D to the seventh ordinary base station 12G can be used as a reference base station for these four base stations, at least the above-mentioned reference base station is required. The relationship between base stations and ordinary base stations is established. That is, the clock speed ratio between the clock of the reference base station and the clock of the ordinary base station is calculated from the clock speed ratio 54, and the clock time of the reference base station and the clock of the ordinary base station are calculated by the clock deviation calculation unit 56. Further, the reception time correction unit 58 corrects the reception time of the radio wave at the normal base station so as to correspond to the time in the clock of the reference base station by using the clock speed ratio and the clock difference. Can do.

  Here, the fourth ordinary base station 12D can communicate with the first reference base station 11A by radio, and behaves as a normal base station as viewed from the first reference base station 11A. Therefore, the time based on the time of the clock 44 of the fourth normal base station 12D can be corrected to the time based on the time 44 of the first reference base station 11A by the reception time correction unit 58. Therefore, if the fourth ordinary base station 12D is the second reference base station 11B which is the reference base station of the fifth ordinary base station 12E to the seventh ordinary base station 12G, first, the fifth ordinary base station 12E to The time relative to the clock 44 of the seventh ordinary base station 12G is corrected by the reception time correction unit 58 to the time relative to the clock 44 of the fourth ordinary base station 12D that is the second reference base station 11B. As described above, the time based on the clock 44 of the fourth normal base station 12D can be corrected to the time based on the clock 44 of the first reference base station 11A. The time based on the clock 44 of the 7 normal base station 12G can be corrected to the time based on the clock of the first reference base station 11A by two corrections by the reception time correction unit 58. In this way, a base station that is not directly communicable with the first reference base station by causing the base station that is a normal base station to function as the second reference base station at the same time as viewed from the first reference base station. Can also be an ordinary base station that indirectly corresponds to the first reference base station.

  Each of the base stations 11 and 12 has a functional configuration as shown in FIG. 4, for example, a transmission code generation unit 72 required when operating as a reference base station, and required when operating as a normal base station. Since the real-time reception time detection unit 78, the detailed reception time detection unit 80, and the reception interval calculation unit 82 are both configured, one base station can simultaneously function as a reference base station and a normal base station. Can have at the same time.

  That is, in FIG. 12, the region 5A is a region surrounding the first reference base station 11A and the ordinary base station corresponding to the first reference base station 11A, and the region 5B is the second reference base station 11B and the second reference base station 11B. This is an area surrounding a normal base station corresponding to the reference base station 11B.

  At this time, the fourth ordinary base station D, which also functions as the second reference base station 11B, sets the reception time difference in the fifth ordinary base station 12E to the seventh ordinary base station 12G as the second reference base station 11B. As a spreading code sequence for calculation, a spreading code sequence different from that transmitted by the first reference base station 11A can be transmitted. Specifically, the notice code PN3 ′, the first spread code PN1 ′, the second spread code PN2 ′, and the spread code PN0 ′ transmitted between the spread codes transmitted by the second reference base station 11B are those Are different from each other, and at the same time, the notice code PN3, the first spread code PN1, the second spread code PN2 and the spread code PN0 transmitted between the spread codes transmitted from the first reference base station 11A. It is different from both.

  FIG. 13 is a flowchart for explaining an example of the control operation of the mobile station positioning system 8 in this embodiment. First, in step SD1, for example, a reception interval calculation routine shown in FIG. 10 is executed, and the first spreading code and the second spreading code transmitted from the first reference base station 11A at a predetermined interval are changed to the first spreading code. A reception interval at the time of reception at the first ordinary base station 12A to the fourth ordinary base station 12D, which is the ordinary base station 12 corresponding to the one reference station 11A, is calculated.

  In SD2 corresponding to the clock speed ratio calculation unit 54, the first normal base station 12A to the fourth normal base station 12D, which are the normal base stations 12 corresponding to the first reference base station 11A calculated in SD1, are used. The reception interval between the first spreading code and the second spreading code, the first spreading code transmitted from the first reference base station 11A in SB6 in the receiving interval calculation routine executed in SD1, and the second Based on the transmission interval with the spreading code, the clock speed ratio between the clock 44 of the first reference base station 11A and the clocks 44 of the first ordinary base station 12A to the fourth ordinary base station 12D is calculated.

  In SD3 corresponding to the clock shift calculation unit 56, for example, in SD1, the reception interval between the first spreading code and the second spreading code in the first ordinary base station 12A to the fourth ordinary base station 12D is calculated. The transmission time of the second spreading code by the first reference base station 11A, the reception time of the second spreading code at each of the first ordinary base station 12A to the fourth ordinary base station 12D, , Based on the propagation time of the true radio wave calculated based on the known distance between the first reference base station 11A and the first ordinary base station 12A to the fourth ordinary base station 12D. The time difference between the time of the clock 44 of the reference base station 11A and the time of the clock 44 of the first ordinary base station 12A to the fourth ordinary base station 12D is that of the first ordinary base station 12A to the fourth ordinary base station 12D. It is calculated for Les.

  In SD4 corresponding to the reception time correction unit 58, the spread codes received at each of the previous first ordinary base station 12A to the fourth ordinary base station 12D are calculated based on the clock 44 of each ordinary base station 12 as a reference. A correction formula for correcting the reception time to a time based on the clock 44 of the first reference base station 11A is calculated. That is, the clock speed ratio calculated in SD2, the time lag calculated in SD3, or the previously known first reference base station 11A and each of the first ordinary base station 12A to the fourth ordinary base station 12D. The equations (3) to (7) are determined using the propagation time of the true radio wave calculated based on the distance.

  In step SD5, for example, a reception interval calculation routine shown in FIG. 10 is executed, and the first spreading code and the first transmission code transmitted from the second reference base station 11B (fourth ordinary base station 12D) at a predetermined interval are executed. A reception interval is calculated when two spreading codes are received by the fifth ordinary base station 12E to the seventh ordinary base station 12G, which are the ordinary base stations 12 corresponding to the second reference station 11B.

  In SD6 corresponding to the clock speed ratio calculation unit 54, the fifth normal base station 12E to the seventh normal base station 12G which are the normal base stations 12 corresponding to the second reference base station 11B calculated in SD5. The reception interval between the first spreading code and the second spreading code, the first spreading code transmitted from the second reference base station 11B in the SB6 in the receiving interval calculation routine executed in SD5, and the second Based on the transmission interval with the spreading code, the clock speed ratio between the clock 44 of the first reference base station 11A and the clocks 44 of the fifth ordinary base station 12E to seventh ordinary base station 12G is calculated.

  In SD7 corresponding to the clock deviation calculation unit 56, for example, in SD5, the reception interval between the first spreading code and the second spreading code in the fifth ordinary base station 12E to the seventh ordinary base station 12G is calculated. The transmission time of the second spreading code by the second reference base station 11B, the reception time of the second spreading code at each of the fifth ordinary base station 12E to the seventh ordinary base station 12G, , Based on the propagation time of the true radio wave calculated based on the known distance between the second reference base station 11B and the fifth ordinary base station 12E to the seventh ordinary base station 12G. The time difference between the time of the clock 44 of the reference base station 11B and the time of the clock 44 of the fifth ordinary base station 12E to the seventh ordinary base station 12G is that of the fifth ordinary base station 12E to the seventh ordinary base station 12G. It is calculated for Les.

  In SD8 corresponding to the reception time correction unit 58, the spread code received in each of the fifth ordinary base station 12E to the seventh ordinary base station 12G is calculated on the basis of the clock 44 of each ordinary base station 12 as a reference. A correction formula for correcting the reception time to a time based on the clock 44 of the second reference base station 11B is calculated. That is, the clock speed ratio calculated in SD6, the time lag calculated in SD7, or the previously known second reference base station 11B and each of the fifth ordinary base station 12E to the seventh ordinary base station 12G. The equations (3) to (7) are determined using the propagation time of the true radio wave calculated based on the distance.

  In SD9 corresponding to the reception time correction unit 58, in each of the fifth ordinary base station 12E to the seventh ordinary base station 12G corrected to the time based on the clock of the second reference base station 11B in SD8. Expressions for correcting the reception time of the received spread code to the time based on the clock of the first reference base station 11A, that is, the expressions (3) to (7) are determined. At this time, since the second reference base station 11B is the fourth ordinary base station 12D, the correction formula in this step is calculated based on the clock of the ordinary base station 12D calculated in the SD4. An expression for converting the time into a time based on the clock of the first reference base station 11A is used. By these steps, an expression for correcting the reception time of radio waves from the mobile station 10 in all the normal base stations 12 to the time based on the clock of the first reference base station 11A is derived.

  In the SD 10 corresponding to the positioning unit 60, a positioning routine shown in FIG. 11 for calculating the position of the mobile station 10 is executed. That is, when the mobile station 10 transmits a radio wave including a spreading code for positioning, each base station 11 and 12 receives the radio wave. The reception times at the first ordinary base station 12A to the fourth ordinary base station 12D corresponding to the first reference base station 11A are based on the clock of the first reference base station 11A using the correction formula calculated at SD4. The time is corrected. Also, the reception times at the fifth ordinary base station 12E to the seventh ordinary base station 12G corresponding to the second reference base station 11B are obtained from the clock of the second reference base station 11B using the correction formula calculated at SD8 and SD9. And the time based on the time of the first reference base station 11A are sequentially corrected. In this way, positioning is performed using the reception times at all the base stations 11 and 12 corrected to the time based on the clock of the first reference base station 11A.

  According to the above-described embodiment, the first reference base station 11A and the second reference base station 11B transmit the same continuous spreading code sequence of the two code lengths using different spreading codes for each reference base station. Therefore, it becomes possible for ordinary base stations corresponding to the respective reference base stations to distinguish the spreading codes, and since a plurality of reference base stations can exist at the same time, it has redundancy in the case where the reference base station fails. be able to. In addition, since the plurality of ordinary base stations have a function as a second reference base station, it is possible to increase the area where positioning is possible in a superimposed manner.

  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, both the reference base station 11 and the ordinary base station 12 have a common functional configuration as shown in FIG. In this way, the base station switches the functions of the reference base station 11 and the ordinary base station 12, or has the functions of the reference base station 11 and the ordinary base station 12 simultaneously as shown in the second embodiment. can do. However, conversely, the present invention is not limited to such a mode, and the base station that operates only as the reference base station 11 does not need to have the reception interval calculation unit 82 that is necessary when operating as the normal base station 12, In the base station that operates only as the normal base station 12, it is not necessary to have the transmission code generation unit 72 that is necessary when operating as the reference base station 11. In this way, the reference base station 11 and the ordinary base station 12 can each have a simple configuration.

  In the above-described embodiment, the reception interval calculation unit 82 in the ordinary base station 12 calculates the reception interval using the reception time detected by the detailed reception time detection unit 80. However, the present invention is not limited to this. The reception interval may be calculated using the reception time detected by the reception time detection unit 78. That is, even if the detailed reception time detection unit 80 is not provided, a certain effect is produced.

  In the above-described embodiment, the interval between the notice code and the first spreading code is set to a predetermined time in the spreading code string generated by the transmission code generating unit 72, but is not limited thereto. . For example, the transmission time between the transmission completion time when the notification code is transmitted and the transmission completion time of the first spreading code generated by the spreading code generation unit 74 with an interval between the notification code and the first spreading code. A value measured each time can also be used as the difference. At this time, for example, the notice code generation unit 76 may transmit information about the difference in the transmission time to the detailed reception time detection unit 80 of the normal base station 12 described later via the control unit 38. In this case, the predetermined time information is transmitted to the ordinary base station 12 via the server 14.

  In the above-described embodiment, the notice code PN3 generated by the notice code generator 76 and the first spread code PN1 and the second spread code PN2 generated by the spread code generator 74 are the same spread code. However, it is not limited to this. That is, the notice code PN3, the first spreading code PN1, and the second spreading code PN2 may be different spreading codes. In this case, the receiving base station 12 receives the same spreading codes as the different spreading codes. While it is necessary to perform synchronization detection processing using a replica code, the reception side PN3, the first spreading code PN1, and the second spreading code PN2 are not mistaken. The same applies to the spread code string generated in the transmission code generation unit 29 of the mobile station 10, and the detection of reception time for the warning code generated by the warning code generation unit 33 and the positioning generated by the spread code generation unit 32. The spreading code for can be the same or different.

  In the above-described embodiment, the spread code string generated by the notice code generation unit 76 is not a spread code PN0 other than the notice code PN3, the first spread code PN1, and the second spread code PN2. However, it is not limited to this. For example, instead of transmitting the spreading code PN0, nothing may be transmitted for a time corresponding to the time for transmitting the spreading code PN0. In this way, power can be saved because radio waves are not transmitted for a time corresponding to the time for transmitting the spread code PN0.

  In the above-described embodiment, the positioning unit 60 performs positioning of the mobile station 10 using the time difference between the reception times of the radio waves from the mobile station 10 in the base stations 11 and 12 (TDOA method). Not limited. For example, if the time of at least the clock 44 of the reference base station 11 and the clock 31 of the mobile station 10 can be synchronized before positioning, the radio wave propagation time calculated from the radio wave transmission time and reception time is used. Thus, positioning of the mobile station 10 can be performed (TOA method).

  In the above-described embodiment, it is determined in steps SB4 and SB7 in FIG. 10 whether or not there is a response from all the normal base stations. However, the present invention is not limited to this, and is necessary for positioning of the mobile station 10, for example. If the response from the smallest ordinary base station matches, the determination of these steps may be affirmed. The same applies to steps SC4 and SC7 in FIG. 11, and the determination of these steps is affirmative when the minimum response from the normal base station 12 required for positioning of the reference base station 11 and the mobile station 10 matches. You may be made to do.

  Further, in the above-described embodiment, in step SC5 of FIG. 11, the reference base station 11 issues a radio wave transmission command for positioning to the mobile station 10, but the present invention is not limited to this. That is, a radio wave transmission command may be issued from any base station 11, 12 capable of wireless communication with the mobile station 10, and a radio wave transmission command is issued from any base station 11, 12 by the positioning server 14. It only has to be determined.

  In the above-described embodiment, the base stations 11 and 12 and the positioning server 14 are connected by the wired cable 52 and can communicate with each other. However, the base stations 11 and 12 are not limited to this mode. The means is not limited as long as communication with the positioning server 14 is possible. For example, the base stations 11 and 12 and the positioning server 14 may be communicable with each other by infrared rays, ultrasonic waves, radio waves, etc. In this case, it is not necessary to connect them with a wired cable.

It is a figure explaining an example of the outline | summary of a structure of the mobile station positioning system 8 of this invention. It is a figure explaining the coordinate provided in the area | region 5 of the mobile station positioning system 8 of this invention. It is a functional block diagram explaining the outline | summary of the function which the mobile station of this invention has. It is a functional block diagram explaining the outline | summary of the function which the base station of this invention has. It is a functional block diagram explaining the outline | summary of the function which the positioning server of this invention has. It is a figure explaining an example of the spreading code sequence which a reference base station transmits, and its time relation. It is a figure explaining an example of the spreading code sequence which a normal base station receives, and its time relation. It is a figure explaining the principle of positioning by a positioning part. It is a flowchart explaining an example of the control action in the positioning by the mobile station positioning system of this invention. 10 is a flowchart illustrating a reception interval calculation routine executed in the flowchart of FIG. 9. 10 is a flowchart illustrating a positioning routine executed in the flowchart of FIG. 9. It is a figure explaining the outline | summary of a structure of the mobile station positioning system 8 in another Example of this invention, Comprising: It is a figure corresponding to FIG. It is a flowchart explaining an example of the control action of the mobile station positioning system 8 in another Example of this invention.

Explanation of symbols

8: Positioning system 11: Reference base station 12: Normal base station 14: Positioning server 54: Clock speed ratio calculation unit 56: Clock deviation calculation unit 58: Reception time correction unit 60: Positioning unit 80: Detailed reception time detection unit 82: Reception interval calculator

Claims (10)

A plurality of base stations receive radio waves transmitted from a mobile station, and estimate the position of the mobile station based on the time difference between reception times of the radio waves received by the plurality of base stations and the positions of the plurality of base stations. A mobile station positioning system,
Among the plurality of base stations, at least one reference base station that transmits a spreading code string including two spreading codes once;
Among the plurality of base stations, two or more ordinary base stations that receive the spreading code sequence transmitted from the reference base station;
A reception interval for detecting the reception time of each of the two spreading codes included in the spreading code sequence received by each of the normal base stations, and calculating the reception interval of the two spreading codes based on the detected reception time A calculation means;
Based on the reception interval at each of the normal base stations of the two spreading codes calculated by the reception interval calculation means, and the transmission interval at which the reference base station transmits the two spreading codes, the normal A clock speed ratio calculating means for calculating a ratio of the clock speed between each of the base stations and the reference base station;
Based on the transmission time of the spreading code sequence by the reference base station, the reception time of the spreading code sequence by each of the ordinary base stations, and the distance between the reference base station and the ordinary base station that are known in advance, A clock deviation calculating means for calculating a time deviation of each clock of the normal base station with respect to a clock of the reference base station;
Each of the ordinary base stations has received the time of reception of the radio wave from the mobile station calculated based on the clock possessed by each of the ordinary base stations, and the normal base station calculated by the clock speed ratio calculating means. Based on the ratio of the clock speed of each of the reference base stations and the time difference of the clock of each of the ordinary base stations with respect to the clock of the reference base station calculated by the clock deviation calculating means A reception time correcting means for correcting the time based on the clock of the station;
The reception time of the radio wave from the mobile station in the normal base station corrected by the reception time correction means, the reception time of the radio wave from the mobile station in the reference base station, and the location information of the normal base station and the reference base station; Positioning means for estimating the position of the mobile station based on:
A mobile station positioning system characterized by comprising: The mobile station positioning system according to claim 1, wherein the transmission of the spreading code string by the reference base station is performed prior to the transmission of radio waves for positioning by the mobile station. Online reception time detection means for detecting the reception time of the radio wave by performing synchronization detection processing of the spread code included in the received radio wave in association with reception of the spread code;
A synchronization detection process of a spread code included in the received radio wave, and an off-line reception time detection unit that detects the reception time of the radio wave with more detailed accuracy than the online reception time detection unit,
The reception interval calculation means determines an offline detection execution section for executing the offline reception time detection means based on a detection result by the online reception time detection means, and the reception times of the two spread codes in the offline detection execution section Detecting by the offline reception time detection means,
The mobile station positioning system according to claim 1 or 2. 4. The mobile station positioning system according to claim 1, wherein the reference base station transmits the same or different spreading codes as the two spreading codes. 5. The mobile station according to any one of claims 1 to 4, wherein the reference base station transmits a spreading code string including the two spreading codes using a spreading code different for each reference base station. Positioning system. A plurality of base stations receive radio waves transmitted from a mobile station, and estimate the position of the mobile station based on the time difference between reception times of the radio waves received by the plurality of base stations and the positions of the plurality of base stations. Mobile station positioning method,
At least one of the plurality of base stations is a reference base station that transmits a spreading code string including two spreading codes once,
At least two of the plurality of base stations are ordinary base stations that receive the spreading code sequence transmitted from the reference base station,
Reception for detecting the reception time of each of the two spreading codes included in the spreading code sequence received by each of the normal base stations, and calculating the reception interval of the two spreading codes based on the detected reception time An interval calculation step;
Based on the reception interval for each of the two spread codes in each of the normal base stations calculated by the reception interval calculation step, and the transmission interval when the reference base station transmits the two spread codes A clock speed ratio calculating step for calculating a ratio of clock speeds of each of the normal base stations and the reference base station;
Based on the transmission time of the spreading code string by the reference base station, the reception time of the spreading code string by each of the ordinary base stations, and the distance between the reference base station and the ordinary base station that are known in advance, A clock deviation calculating step of calculating a time deviation of each clock of the normal base station with respect to the clock of the reference base station;
Each of the ordinary base stations has received the time of reception of the radio wave from the mobile station calculated based on the clock possessed by each of the ordinary base stations, and the normal base station calculated by the clock speed ratio calculating step. Based on the ratio of the clock speed of each of the reference base stations and the time difference of each clock of the normal base station with respect to the clock of the reference base station calculated by the clock deviation calculation step, the reference base station A reception time correction step of correcting the time based on the clock of the station;
The reception time of radio waves from the mobile station at the normal base station corrected by the reception time correction step, the reception time of radio waves from the mobile station at the reference base station, and the position information of the normal base station and the reference base station A positioning step of estimating the position of the mobile station based on
A mobile station positioning method characterized by comprising: The mobile station positioning method according to claim 6, wherein the transmission of the spreading code string by the reference base station is performed prior to the transmission of radio waves for positioning by the mobile station. An on-line reception time detection step of detecting the reception time of the radio wave by performing synchronization detection processing of the spread code included in the received radio wave in association with reception of the spread code;
A synchronization detection process of a spread code included in the received radio wave, and an off-line reception time detection step of detecting the reception time of the radio wave with more detailed accuracy than the online reception time detection step,
The reception interval calculation step determines an off-line detection execution section for executing the off-line reception time detection step based on a detection result of the on-line reception time detection step, and the reception times of the two spreading codes in the off-line detection execution section The mobile station positioning method according to claim 6 or 7, wherein the mobile station positioning is detected by the off-line reception time detection step. The mobile station positioning method according to any one of claims 6 to 8, wherein the reference base station transmits the same or different spreading codes as the two spreading codes. The mobile station according to any one of claims 6 to 9, wherein the reference base station transmits a spreading code string including the two spreading codes using a spreading code different for each reference base station. Positioning method.

Images