JP2009236781A - Mobile station positioning system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a mobile station positioning system in which the positioning of a mobile station with high accuracy can be performed with no increase in the number of calculation or with neither upsizing nor cost increase of a mobile station even if the number of base stations is increased. <P>SOLUTION: The mobile station positioning system includes a correlation calculating section 64 for calculating the magnitude of the correlation value between a spreading code and replica code included in radio waves received by a plurality of base stations 12 on the basis of a predetermined relationship, a correlation value error converting section 68 for calculating an error-related value on a communication error in the wireless communication from a mobile station 10 to each of the base stations 12 from a relationship previously stored on the basis of the magnitude of the correlation value calculated by the correlation calculating section 64 for each of the base stations 12, a weighting matrix generating section 72 for determining a weighting matrix representing the weight of each of the base stations 12 in the positioning by the relationship previously stored on the basis of the error-related value, and a positioning section for calculating the position of the mobile station 10 by using the result of the reception of the radio waves transmitted from the mobile station 10 and weighting matrix in each of the plurality of base stations 12. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a mobile station positioning system that calculates (positions) the position of a mobile station that transmits a radio wave including a spread code based on reception results of radio waves transmitted from the mobile station by a plurality of base stations. In particular, a weight matrix for weighting the base station used for positioning of the mobile station is calculated based on the reception result at each base station of the radio wave transmitted from the mobile station, and the mobile station uses the weight matrix to calculate the weight matrix. The present invention relates to a technique that can improve positioning accuracy by performing positioning.

  In recent years, a technique for performing transmission / reception of radio waves between a radio station at a known position and a radio station at an unknown position and calculating the position of the radio station at an unknown position based on the reception result has been widely used in recent years. . For example, a positioning system called GPS (Global Positioning System). In this GPS, a mobile terminal receives radio waves from a plurality of satellites that orbit at a predetermined speed on a predetermined orbit, and the position of the mobile terminal is calculated based on the reception result. In addition, in principle, a similar technique can be used to receive a radio wave transmitted by a movable mobile station by a base station at a known position and calculate the position of the mobile station based on the reception result. Can do.

  When performing positioning based on such radio wave reception results, it is desirable to perform radio wave transmission and reception in a favorable environment. However, in an environment where radio wave reflection can occur, a signal received due to interference between a direct wave and a reflected wave due to multipath or the like becomes an interference wave and communication distortion occurs. Such communication affects, for example, the measurement of the reception time of radio waves, and causes an error. For this reason, the error in the positioning result also increases.

  In Patent Document 1, an error deterioration amount related to each distance measurement result is calculated from the distance measurement result and the position of each reference station as an amount of error in which each distance measurement result affects the reference error. A technique is disclosed in which a weighting coefficient for weighting each evaluation result is calculated based on an error deterioration amount, and positioning of a detection target station is performed using the calculated weighting coefficient or the like. According to such a technique, it is possible to predict an error included in the measurement of the distance between the reference station and the detection target station, control the influence on the position calculation, and reduce the error included in the position calculation result.

  Further, Patent Document 2 discloses that the radio wave arrived from the positioning satellite is a direct wave by comparing the estimated elevation angle of the positioning satellite with the elevation angle of the feature obtained from the imaging data generated by the imaging device. A positioning device that can determine whether a wave is a reflected wave is disclosed. According to this technique, it is possible to perform positioning by selecting a pseudo distance with high accuracy, and it is possible to prevent deterioration in positioning accuracy under multipath conditions.

JP 2006-90913 A JP 2007-93483 A

  For example, as shown in Patent Document 1 and Patent Document 2, a technique for performing accurate positioning in an environment where multipath occurs has been proposed, but it cannot be said that the problem has been sufficiently solved. . That is, according to the technique disclosed in Patent Document 1, there is a problem that when the number of reference stations increases, the calculation amount for calculating the error deterioration amount increases. Further, according to the technique disclosed in Patent Document 2, it is necessary to include an image pickup device for generating image pickup data, an image processing device, and the like, and the equipment on the mobile station side becomes large or increases in cost. There is a problem.

  The present invention has been made against the background of the above circumstances. The object of the present invention is to set a weight according to the base station and calculate the position of the mobile station using the weight. It is an object of the present invention to provide a mobile station positioning system capable of performing highly accurate positioning of a mobile station without increasing the amount of calculation even if the number increases or without increasing the size and cost of the mobile station.

  The gist of the invention according to claim 1 for solving this problem is that (a) a plurality of base stations receive radio waves including spreading codes transmitted from a mobile station, and the plurality of base stations A mobile station positioning system that calculates a position of the mobile station based on reception results of radio waves received at the plurality of base stations by a positioning server connected so as to be capable of data communication, and (b) the plurality of bases Standardization of a spread code included in a radio wave received by a station and having a predetermined amplitude after reception, and a replica code that is a pre-stored spread code identical to the spread code included in the radio wave transmitted by the mobile station A correlation calculation unit for calculating the magnitude of the correlation value based on a predetermined relationship; and (c) a communication error in radio communication between the standardized correlation value and each of the mobile station and the plurality of base stations. Error-related values related to communication errors in wireless communication from the mobile station to each of the plurality of base stations based on the magnitude of the normalized correlation value calculated by the correlation calculation unit And (d) the error in the wireless communication from the mobile station to each of the plurality of base stations, calculated by the correlation value error conversion unit. A weight matrix generation unit for determining a weight matrix representing a weight in each positioning of the plurality of base stations based on a relation value stored in advance, and (e) the plurality of radio waves transmitted from the mobile station The relationship stored in advance using the reception result at each of the plurality of base stations when the base station receives the weight matrix generated by the weight matrix generation unit And having a positioning portion to further calculate the position of the mobile station.

  The gist of the invention according to claim 2 is that: (a) the plurality of base stations includes a plurality of control base stations capable of performing wireless communication with the mobile station in order to control operation of the mobile station; (B) a control base station selection unit that selects, from among the plurality of control base stations, a control base station that establishes wireless communication with the mobile station as a selection control base station that controls the operation of the mobile station And (c) a combination of base stations to be selected base stations that are base stations used for positioning of the mobile station when each of the plurality of control base stations stored in advance is the selected control base station. A base station selection unit that selects a combination of the selected base stations for the selected control base station selected by the control base station selection unit, based on the information regarding, (d) the correlation calculation unit, Selected by the base station selector Calculated based on a pre-stored relationship between a spread code included in the radio wave received by the selected base station and having a predetermined amplitude after reception, and the size of a normalized correlation value between the replica code, (E) The correlation value error conversion unit is configured so that the correlation calculation unit calculates a correlation between a magnitude of the normalized correlation value and a communication error in wireless communication between each of the mobile station and the selected base station. Calculating an error-related value related to a communication error in wireless communication from the mobile station to each of the selected base stations, for each of the selected base stations, based on the calculated magnitude of the normalized correlation value; (f) The weight matrix generation unit is stored in advance based on the error-related value in wireless communication from the mobile station to each of the selected base stations, calculated by the correlation value error conversion unit. And (g) the positioning unit selects the selection when each of the selected base stations receives a radio wave transmitted from the mobile station. The position of the mobile station is calculated based on the relationship stored in advance using the reception result at each base station and the weight matrix generated by the weight matrix generation unit.

  The gist of the invention according to claim 3 is that: (a) out of the plurality of base stations, all the base stations that have received radio waves from the mobile station that is a positioning target are (B) the correlation calculation unit is included in the radio waves received by the selected base station selected by the base station selection unit, and is predetermined after reception. (C) The correlation value error conversion unit calculates the normalized correlation value between the spread code set to the amplitude of the replica code and the replica code based on a previously stored relationship. Based on the magnitude of the normalized correlation value calculated by the correlation calculation unit based on a pre-stored relationship between the magnitude and a communication error in wireless communication between each of the mobile station and the selected base station, the mobile Station to the selected base station An error-related value related to a communication error in wireless communication to each is calculated for each of the selected base stations, (d) the weight matrix generation unit is calculated from the mobile station calculated by the correlation value error conversion unit Based on the error-related value in wireless communication to each of the selected base stations, a weight matrix representing weights in the respective positioning of the selected base station is determined according to a previously stored relationship, and (e) the positioning unit is , Using a reception result at each of the selected base stations when each of the selected base stations receives a radio wave transmitted from the mobile station, and a weight matrix generated by the weight matrix generation unit, The position of the mobile station is calculated based on the relationship.

  The gist of the invention according to claim 4 is: (a) reception in which the base station detects a reception time of a radio wave based on a time when a peak of a normalized correlation value calculated by the correlation calculation unit is generated. And (b) the positioning unit calculates the position of the mobile station based on the reception time detected by the reception time detection unit of each of the plurality of selected base stations. And

  The gist of the invention according to claim 5 is that: (a) the base station includes a reception intensity detection unit that detects reception intensity when receiving a radio wave transmitted from a mobile station; The positioning unit is to calculate the position of the mobile station based on the reception strength detected by the reception strength detection unit of each of the plurality of base stations used for positioning of the mobile station.

  Preferably, the gist of the invention according to claim 6 is that the base station includes the correlation value error conversion unit.

  Preferably, the gist of the invention according to claim 7 is that the positioning server includes the correlation value error conversion unit.

  According to the mobile station positioning system according to claim 1, the correlation calculation unit includes a spread code included in radio waves received by the plurality of base stations and having a predetermined amplitude after reception, and the mobile station transmits The magnitude of the normalized correlation value between the spread code included in the radio wave and the replica code that is the same pre-stored spread code is calculated based on a predetermined relationship, and is calculated in advance by the correlation value error conversion unit. Calculated by the correlation calculation unit based on a pre-stored relationship between the magnitude of the normalized normalized correlation value and a communication error in wireless communication of a spread code transmitted from the mobile station and received by each of the plurality of base stations. On the basis of the magnitude of the normalized correlation value, an error-related value related to a communication error in wireless communication from the mobile station to each of the plurality of base stations is determined by the plurality of base stations. Pre-stored based on the error-related values in wireless communication from the mobile station to each of the plurality of base stations, calculated for each and calculated by the correlation value error conversion unit by the weight matrix generation unit Based on the determined relationship, a weight matrix representing weights in positioning of the plurality of base stations is determined, and the positioning unit receives the radio waves transmitted from the mobile station by the plurality of base stations. Since the position of the mobile station is calculated according to a pre-stored relationship using the reception result at each base station and the weight matrix generated by the weight matrix generation unit, the spread transmitted from the mobile station The mobile station position is calculated in consideration of the weight for each of the plurality of base stations that have received the radio wave including the code, and the mobile station position is calculated using the weight. In such a case, the mobile station positioning system can perform highly accurate mobile station positioning without increasing the amount of computation even if the number of base stations increases or without increasing the size and cost of the mobile station. Can be provided.

  According to the mobile station positioning system according to claim 2, the plurality of base stations include a plurality of control base stations capable of performing wireless communication with the mobile station in order to control operation of the mobile station, The control base station selection unit selects, from among the plurality of control base stations, a control base station that establishes wireless communication with the mobile station as a selection control base station that controls the operation of the mobile station. Information about the selection control base station selected by the control base station selection unit by the selection unit, and when each of the plurality of control base stations stored in advance is the selection control base station, the mobile station Based on the information on the combination of base stations to be selected base stations that are base stations used for positioning, the previous one of the plurality of base stations for the selected control base station selected by the control base station selection unit A combination of the selected base stations that are base stations used for positioning of the mobile station is selected, and the correlation calculation unit is included in the radio waves received by the selected base station selected by the base station selection unit, and is predetermined after reception. The magnitude of the normalized correlation value between the spread code having the amplitude of the replica code and the replica code is calculated based on a previously stored relationship, and the correlation value error conversion unit calculates the normalized correlation value calculated in advance. The magnitude of the normalized correlation value calculated by the correlation calculation unit based on a pre-stored relationship between the magnitude and a communication error in wireless communication of a spreading code transmitted from the mobile station and received by each of the selected base stations And calculating an error-related value related to a communication error in wireless communication from the mobile station to each of the selected base stations for each of the selected base stations, Based on the error-related values in the wireless communication from the mobile station to each of the selected base stations calculated by the correlation value error converter, each of the selected base stations is generated according to a previously stored relationship. A weight matrix representing weights in positioning of the selected base station, and the positioning unit receives a reception result at each of the selected base stations when each of the selected base stations receives a radio wave transmitted from the mobile station, and the weight Since the position of the mobile station is calculated according to a previously stored relationship using the weight matrix generated by the matrix generation unit, for example, the base station can be A spreading code transmitted from the mobile station for each of the selected control base station suitable for control and the selected base station in combination with the selected control base station The base station weight is calculated based on the reception result of receiving the radio wave including the signal, the position of the mobile station is calculated, and the base station has a larger communication error with the mobile station. When calculating the position of a mobile station using a weight according to the base station, the calculation amount increases even if the number of base stations increases, or the accuracy does not increase with an increase in the size and cost of the mobile station It is possible to provide a mobile station positioning system that can perform positioning of a mobile station having a high level.

  According to the mobile station positioning system according to claim 3, all the base stations that have received radio waves from the mobile stations targeted for positioning from among the plurality of base stations by the base station selection unit. The base station is selected as a selected base station to be used for positioning of the mobile station, and the correlation calculation unit is included in radio waves received by the selected base station selected by the base station selection unit, and is spread to a predetermined amplitude after reception The correlation value error conversion unit calculates the magnitude of the normalized correlation value between the code and the replica code based on a previously stored relationship, Based on the magnitude of the normalized correlation value calculated by the correlation calculation unit from a pre-stored relationship with a communication error in wireless communication of a spreading code transmitted and received by each of the selected base stations Calculating an error-related value related to a communication error in radio communication from the mobile station to each of the selected base stations for each of the selected base stations, and the weight matrix generation unit is calculated by the correlation value error conversion unit Determining a weight matrix representing a weight in each positioning of the selected base station according to a previously stored relationship based on the error-related value in wireless communication from the mobile station to each of the selected base station, The unit uses a reception result at each of the selected base stations when each of the selected base stations receives a radio wave transmitted from the mobile station, and a weight matrix generated by the weight matrix generation unit, Since the position of the mobile station is calculated according to a pre-stored relationship, all the base stations that have received radio waves including a spread code transmitted from the mobile station The position of the mobile station is calculated in consideration of the weight for each, and the weight is reduced as the base station has a larger communication error with the mobile station. Therefore, the mobile station using the weight corresponding to the base station When calculating the position, even if the number of base stations increases, the amount of computation increases, or the mobile station can perform positioning with high accuracy without increasing the size and cost of the mobile station A station positioning system can be provided.

  According to the mobile station positioning system of claim 4, the base station receives a radio wave reception time based on a time when a peak of a normalized correlation value calculated by the correlation calculation unit occurs. And the positioning unit calculates the position of the mobile station based on the reception time detected by the reception time detection unit of each of the plurality of selected base stations, and is thus calculated by the correlation calculation unit. Based on the change in the normalized correlation value, the reception time can be detected accurately, and the position of the mobile station is calculated in consideration of the weight for each of the base stations. Since the base station with a larger communication error has a smaller weight, when calculating the position of the mobile station using the weight according to the base station, the amount of computation increases even if the number of base stations increases. , Or it is possible to provide a mobile station positioning system capable of performing positioning with high accuracy mobile station without size and cost of the mobile station.

  According to the mobile station positioning system according to claim 5, the base station has a reception intensity detection unit that detects a reception intensity when the radio wave transmitted from the mobile station is received, and the positioning unit includes the mobile station Since the position of the mobile station is calculated based on the reception intensity detected by the reception intensity detection unit of each of the plurality of base stations used for station positioning, radio waves that can be detected relatively easily The base station can calculate the position of the mobile station based on the received intensity, and the position of the mobile station is calculated in consideration of the weight for each of the base stations. Since the weight is reduced, when calculating the position of the mobile station using the weight according to the base station, the amount of calculation increases even if the number of base stations increases, or the mobile station becomes larger or more expensive. cost It is possible to provide a mobile station positioning system capable of performing positioning with high accuracy mobile station without. In addition, when a device that is designed on the premise of detecting reception intensity, such as a wireless LAN, is used as a base station, the configuration for positioning can be simplified.

  According to the mobile station positioning system according to claim 6, since the base station includes the correlation value error conversion unit, the error is determined based on the normalized correlation value detected in each base station. A related value can be calculated.

  According to the mobile station positioning system according to claim 7, since the positioning server is configured to include the correlation value error conversion unit, the positioning server performs an operation associated with the calculation of the error related value for each base station. Can be aggregated and executed.

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

  FIG. 1 is a diagram illustrating an example of a mobile station positioning system 6 according to the present invention. As shown in FIG. 1, a mobile station positioning system 6 of the present invention includes a mobile station 10 that can move in a predetermined area 8 and can transmit a radio wave including a positioning signal, and the mobile station. A plurality of base stations 12 that receive radio waves transmitted from 10 and calculate predetermined reception results, and positioning that calculates the position of the mobile station 10 based on reception results respectively calculated by the plurality of base stations 12 A server 14 is included. Further, each of the plurality of base stations 12 and the positioning server 14 are connected via a communication cable 20 so that information can be exchanged. In the region 8 to which the mobile station positioning system 6 of this embodiment is applied, for example, a coordinate system is defined as shown in FIG. 1, and the positions of the mobile station 10 and the base station 12 in this region 8 are, for example, It is expressed using common coordinates as shown in FIG.

  In FIG. 1, four base stations 12 (first base station 12A to fourth base station 12A in this specification) are designated as first base station 12A, second base station 12B, third base station 12C, and fourth base station 12D. If the stations 12D are not distinguished from each other, they are referred to as base stations 12.), but the number of base stations is limited to four if the number exceeds the minimum number required for positioning of the mobile station described later. Not. The area 8 is also an area where the position of the mobile station 10 can be calculated (positioned) by the base station 12. In FIG. 1, one mobile station 10 is provided. However, if the positioning radio waves transmitted by the mobile station 10 are mutually identifiable, a plurality of mobile stations 10 are provided. Can do.

  FIG. 2 is a block diagram for explaining an overview of functions of the mobile station 10. The mobile station 10 includes an antenna 26, a mobile station radio unit 22, an electronic control device 23, and the like. The electronic control unit 23 includes a so-called microcomputer having a CPU, a RAM, a ROM, an input / output interface, and the like, for example. The CPU uses a temporary storage function of the RAM, and performs signal processing according to a program stored in the ROM in advance. By performing the processing, the processing in the mobile station control unit 24 described later is executed.

  The mobile station radio unit 22 implements a so-called radio communication function, and transmits and receives radio waves using an antenna 26. For example, the mobile station radio unit 22 transmits radio waves including a spread code for calculating a correlation value to the base station 12. In addition, a radio wave including a command regarding the operation of the mobile station 10 transmitted from the base station 12 is received. The mobile station radio unit 22 generates a carrier wave having a predetermined frequency, modulates the carrier wave based on a signal transmitted by radio waves, performs a digital modulation, and outputs the modulated carrier wave to a predetermined output. It has a transmission amplifier to amplify. Further, the mobile station radio unit 22 is realized by a reception amplifier that amplifies the received wave received by the antenna 26, a filter that extracts only a predetermined frequency component from the received wave, a demodulator that performs demodulation by digital demodulation or a detector, and the like. Including receiving function. At this time, for example, so-called digital communication is preferably used as the wireless communication performed by the mobile station wireless unit 22, and therefore the mobile station wireless unit 22 includes a mechanism for modulation or demodulation necessary for the digital communication.

  Here, the radio wave transmitted by the mobile station radio unit 22 of the mobile station 10 includes, for example, a code for identifying the individual mobile station 10 in the header portion of the signal wave included in the radio wave, or by the individual mobile station 10 It is transmitted by a predetermined method such as transmitting different spreading codes. Therefore, the mobile station that has received the radio wave can identify the mobile station 10 from which the received radio wave is transmitted by analyzing the received radio wave according to the predetermined method.

  The antenna 26 is used when the mobile station radio unit 22 transmits and receives radio waves, and an antenna suitable for the frequency of radio waves to be transmitted and received is used. Further, when the distance from the mobile station 10 is the same, the antenna 26 is omnidirectional with respect to at least the propagation direction of the radio wave so that the base station 12 having the same distance from the antenna 26 can receive the radio wave regardless of the direction from the mobile station 10. A suitable antenna is preferably used.

  The mobile station control unit 24 is realized by the electronic control unit 23 and controls the mobile station radio unit 22. Specifically, for example, the mobile station control unit 24 performs transmission / reception switching, carrier frequency setting, and output setting in the transmission amplifier for the mobile station radio unit 22. The setting values in these controls are determined based on a result of communication with the base station 12, for example, based on a command transmitted from the base station 12. The mobile station control unit 24 also obtains a command related to the control operation of the mobile station 10 from the base station 12 by receiving the mobile station radio unit 22 and analyzing the contents of the radio waves from the decoded base station 12. . Further, the mobile station control unit 24 reads out the spreading code transmitted by the mobile station 10 by radio waves, for example, by reading the spreading code stored from a storage means (not shown), or a predetermined generation method, for example, a predetermined primitive polynomial. Determine by generating based on.

  FIG. 3 is a block diagram illustrating an outline of an example of the functions of the base station 12. The base station 12 includes an antenna 36, a base station radio unit 32, an electronic control device 33, a clock 40, a communication interface 42, and the like. The electronic control unit 33 includes a so-called microcomputer having a CPU, a RAM, a ROM, an input / output interface and the like, for example, and the CPU is stored in the ROM in advance using the temporary storage function of the RAM. By performing signal processing according to the program, processing in a base station control unit 62 and the like to be described later is executed.

  The base station radio unit 32 realizes a so-called radio communication function, and transmits and receives radio waves using the antenna 36. The base station radio unit 32 transmits radio waves including a command for controlling the operation of the mobile station 10. For example, a command for starting transmission of radio waves for positioning is transmitted to the mobile station 10. Further, the base station radio unit 32 receives the radio wave transmitted by the mobile station 10, and passes the contents to a correlation value calculation unit 64, which will be described later, as necessary, to execute processing. That is, the base station radio unit 32 generates an oscillator that generates a carrier wave having a predetermined frequency, modulates the carrier wave based on a signal transmitted by radio waves, and performs a modulator that performs digital modulation and the like. Demodulator having a transmission amplifier that amplifies the output, a reception amplifier that amplifies the received wave received by the antenna 36, a filter that extracts only a predetermined frequency component from the received wave, and demodulation by digital demodulation or a detector It is realized by a vessel. At this time, for example, so-called digital communication is preferably used for the wireless communication performed by the base station wireless unit 32, and thus the base station wireless unit 32 includes a mechanism for modulation or demodulation necessary for the digital communication.

  Further, the base station radio unit 32 and the mobile station radio unit 22 establish communication between the two before performing radio communication with each other. Specifically, for example, a base station radio unit 32 transmits a radio call signal to the mobile station radio unit 22, and the mobile station radio unit 22 of the mobile station 10 that can respond sends a response signal in response to the call signal. Send back. Then, processing such as determination of a wireless channel (frequency) and modulation method used for communication between the base station radio unit 32 and the mobile station radio unit 22 is performed.

  The antenna 36 is used when the base station radio unit 32 transmits and receives radio waves, and an antenna suitable for the frequency of radio waves to be transmitted and received is used. Further, an antenna is provided so that radio waves can be received when the mobile station 10 exists at the same distance from the base station 12 regardless of the position of the mobile station 10, that is, the direction of the mobile station 10 viewed from the base station 12. For the antenna 36, an antenna that is omnidirectional at least in the propagation direction of radio waves is preferably used.

  The clock 40 measures time, and is referred to, for example, when the peak time detection unit 70 detects the time when the correlation value has a peak. Each base station 12 has its own clock, and their times are synchronized in advance.

  The communication interface 42 performs information communication between another base station 12 connected by the communication cable 20 and the positioning server 14. Specifically, the reception time of the radio wave detected by the peak time detection unit 70 of the base station 12, the standard deviation value of the error calculated by the correlation value error conversion unit 68, or the radio wave transmitted from the mobile station 10 In addition to being transmitted from the base station 12 to the positioning server 14, an instruction regarding the operation of the base station 12 transmitted from the positioning server 14 is received.

  FIG. 4 is a functional block diagram for explaining an overview of the control functions of the electronic control unit 33 of the base station 12 of FIG.

  Among these, the base station control unit 62 controls the base station radio unit 32. Specifically, for example, the base station control unit 62 performs transmission / reception switching, carrier frequency setting, transmission amplifier output setting, and the like for the base station radio unit 32. The setting values in these controls are determined based on the result of communication with the positioning server 14 or the mobile station 10 described later. The base station control unit 62 controls operations of a correlation value calculation unit 64, a correlation value error conversion unit 68, a peak time detection unit 70, and the like which will be described later. Further, the base station control unit 62 analyzes the contents of the radio wave transmitted by the mobile station 10 that is received and decoded by the base station radio unit 32. Similarly, the base station control unit 62 analyzes the content transmitted from the positioning server 14 received at the communication interface 42 and extracts a command related to the control operation of the base station 12. Further, the base station control unit 62 transmits necessary information to other devices via the communication interface 42 and the base station radio unit 32.

  The correlation value calculation unit 64 calculates a correlation value between a code included in a positioning radio wave transmitted from the mobile station 10 and a replica code of the spread code. Specifically, the correlation value calculation unit 64 has the same replica code as the code transmitted from the mobile station 10 in advance, and the replica code and the spread code extracted from the received radio wave from the mobile station 10. By inputting (received code) into a known matched filter, a correlation value between the two can be obtained. This matched filter calculates, for example, the sum of logical sums for each bit, and corresponds to a predetermined relationship for calculating a correlation value. Here, when the spreading code transmitted / received between the mobile station 10 and the base station 12 is communication by digital modulation, that is, when the code consists of data consisting of 1 and -1 or 1 and 0, the base station The code received by the wireless unit 62 is used as it is. On the other hand, when the spreading code transmitted / received between the mobile station 10 and the base station 12 is communication by analog modulation, the spreading code received by the base station radio unit 62 has a predetermined amplitude, for example, After being amplified or attenuated to have the same amplitude as the replica code, the correlation value with the replica code is calculated. In this case, since the spread code received by the base station radio unit 62 is adjusted to have a predetermined amplitude, for example, the same amplitude as the replica code, it is calculated by the correlation value calculation unit 64. The correlation value is a normalized normalized correlation value. In the following description, the correlation value includes this normalized correlation value.

  Here, the correlation value calculation unit 64 calculates a correlation value with the replica code at a predetermined interval (clock speed) for a signal extracted from the radio wave from the mobile station 10 received by the base station radio unit 32. As described above, since the spreading code included in the radio wave transmitted from the mobile station 10 has a property of increasing only when the autocorrelation is the same phase, the correlation value calculated by the correlation value calculation unit 64 is When the station radio unit 32 receives the received code, that is, when the received code and the replica code are in phase (synchronized), a peak occurs, but before and after that, the value is low. The correlation value calculation unit 64 corresponds to the correlation calculation unit.

  Further, the peak time detecting unit 70 detects the time when the correlation value between the received code and the replica code calculated by the correlation value calculating unit 64 has a peak with reference to the clock 40, for example. . As described above, the time when the correlation value between the received code and the replica code has peaked is detected as the received time when the received code is received. The reception time is also a time at which the reception code and the replica code are synchronized, and is also referred to as a synchronization time. This peak time detection unit 70 corresponds to a reception time detection unit.

  The relationship storage unit 66 detects an error in detection of the synchronization time detected by the peak time detection unit 70 corresponding to the magnitude of the peak value of the correlation value calculated by the correlation value calculation unit 64 and the magnitude of the peak value. The standard deviation values are stored in association with each other. The value of the standard deviation of the error corresponds to the error related value. Generally, in wireless communication, jitter, that is, time fluctuation that appears in communication transmission occurs. This jitter appears at the rise time of the signal waveform and the arrival interval of packets. This jitter may also occur in transmission / reception of the spreading code transmitted from the mobile station 10 and received at the base station 12. In such a case, the received code received by the base station 12 includes jitter, and the spread code transmitted by the mobile station 10 and the code that is completely identical to the replica code are not obtained. In this case, the peak of the correlation value calculated by the correlation value calculation unit 64 does not become sharp. For this reason, an error also occurs at the time when the correlation value detected by the peak time detection unit 70 reaches a peak.

  FIG. 5 illustrates the influence of jitter when jitter occurs in the transmission / reception of spreading codes from the mobile station 10 to the base station 12 described above. In FIG. 5, the quantity (index) surrounded by an ellipse is an observable quantity, while the quantity (index) enclosed by a square is an unobservable quantity. As shown in FIG. 5, when jitter occurs, the magnitude of the jitter and the peak value of the correlation value have a negative correlation, that is, the peak value of the correlation value decreases as the jitter magnitude increases. On the other hand, the magnitude of the jitter and the error in detecting the synchronization time (synchronization time detection error) have a positive correlation, that is, there is a relationship in which the magnitude of the synchronization time detection error increases as the jitter magnitude increases. Further, the magnitude of the error (positioning error) between the position of the mobile station 10 and the position of the true mobile station 10 calculated by the TDOA positioning unit 74 described later is a positive correlation, that is, the synchronization time. As the detection error increases, the positioning error also increases. Note that the length of the spreading code transmitted from the mobile station 10 to the base station 12 (the length of the code length) and the synchronization time detection error are negative correlation, that is, the synchronization time detection error when the code length is increased. Has a small relationship.

  In addition, as shown in FIG. 5, the magnitude of jitter cannot be directly detected, but has a fixed relationship with the peak value of the correlation value, so that the jitter size is estimated from the peak value of the correlation value. Can do.

  FIG. 6 is a diagram illustrating an example of information stored in the relationship storage unit 66. In FIG. 6, the magnitude of the peak value of the correlation value calculated by the correlation value calculation unit 64 and the value of the magnitude of jitter corresponding to the magnitude of the peak value are stored in association with each other. Specifically, these values are randomly calculated by a predetermined number of times so that the average of the peak value of the correlation value becomes the value described in the left column of FIG. This is obtained by determining the amount of jitter, calculating the standard deviation of the determined number of jitters of the predetermined number of times, and entering the standard deviation in the right column of FIG.

  The correlation value error conversion unit 68 corresponds to the peak value of the correlation value based on the information stored in the relationship storage unit 66 and the information about the peak value of the correlation value calculated by the correlation value calculation unit 64. The error value to be calculated is calculated. Specifically, the correlation value calculated by the correlation value calculation unit 64 from information on the magnitude of jitter corresponding to each of the magnitudes of the peak values of the correlation values stored in the relationship storage unit 66. The value of the magnitude of the standard deviation of the amount of jitter corresponding to the peak value is read out. The correlation value error conversion unit 68 corresponds to the correlation value error conversion unit.

  FIG. 7 is a diagram for explaining the outline of the configuration of the positioning server 14. As shown in FIG. 7, the positioning server 14 corresponds to a CPU, corresponds to an electronic control device 48 that performs necessary arithmetic processing, RAM, ROM, a hard disk, etc., and receives information according to instructions from the electronic control device 48 or the like. Are readable and stored in the storage device 50, the input / output interface 52, and the input / output interface 52, and the input device 53 such as a keyboard and a mouse that accepts an input operation from the user to the positioning server 14 and the operation by the positioning server 14 It is configured to include a so-called computer including an output device 54 for displaying a result and the like, a communication interface 46, and the like. The CPU uses the temporary storage function of the RAM and stores it in the ROM in advance. Signal processing can be performed according to the stored program.

  The communication interface 46 performs information communication with another base station 12, another positioning server 14, or the shared device 16 through the communication cable 20, for example. The communication interface 48 transmits, for example, a command related to the control operation of the base station 12 from the positioning server 14 to the base station 12, and information related to the position of the mobile station 10 calculated by the TDOA positioning unit 74 described later. Information transmitted from the station 12, for example, information related to the reception time of radio waves at the base station 12 is received. The reception time of the radio wave at the base station 12 is detected by the reception time detection unit 38 as the reception time of the spread code transmitted from the mobile station 10.

  FIG. 8 is a functional block diagram for explaining an overview of the functions of the electronic control device 48 of the positioning server 14. These functions are realized, for example, by executing a predetermined program in the positioning server 14 of FIG. Among these, the base station selection unit 80 selects the base station 12 used for positioning of the mobile station 10 in the TDOA positioning unit 74 described later. In this embodiment, the base station selection unit 80 receives the radio wave including the spread code transmitted from the mobile station 10, specifically, the radio wave including the spread code transmitted from the mobile station 10. Are received and transmitted to the server, and all base stations 12 whose reception times are transmitted by the positioning server 14 are selected as base stations used for positioning. The base station selection unit 80 corresponds to the base station selection unit.

The TDOA positioning unit 74 calculates the position of the mobile station 10 based on the time difference between the reception times of the radio waves from the mobile stations 10 detected in the four base stations 12 (TDOA (Time Difference of Arrival) method). The coordinates of the mobile station are (x, y), the coordinates indicating the position of the first base station 12A are (x _B1 , y _B1 ), the coordinates of the second base station 12B are (x _B2 , y _B2 ), and the third base When the coordinates of the station 12C are (x _B3 , y _B3 ) and the coordinates of the fourth base station 12D are (x _B4 , y _B4 ), the position of the mobile station is expressed by the following equation (1). Here, the coordinates of the base station 12 and the mobile station 10 are represented by a coordinate system defined as shown in FIG. 1, for example.
(x _B1 −x) ² + (y _B1 −y) ² = {c × (Tr ₁ −Ts)} ²
(x _B2 −x) ² + (y _B2 −y) ² = {c × (Tr ₂ −Ts)} ²
(x _B3 −x) ² + (y _B3 −y) ² = {c × (Tr ₃ −Ts)} ²
(x _B4 −x) ² + (y _B4 −y) ² = {c × (Tr ₄ −Ts)} ² … (1)
Here, Tr ₁ to _Tr 4 (sec), respectively, signal reception time in the first base station 12A to the fourth base station 12D, Ts is the transmission time of radio waves at the mobile station 10, for example from the mobile station 10 It is transmitted to the base station 12 by radio waves and obtained by the base station 12 receiving it. That is, the (1) in the right-hand side of each equation of type _{(Tr i -Ts) (i =} 1,2, ...) represents the radio wave propagation time from the mobile station 10 to the base station 12i, c × _(Tr i -Ts) represents the distance between the mobile station 10 and the base station 12i. Equation (1) is a simultaneous equation with x, y, and Ts as unknowns.

ここで、（２）式において、Ｒ_２１は、第２基地局１２Ｂと移動局１０との距離と、第１基地局１２Ａと移動局１０との距離との差を表わす。また、同様にＲ_３１は、第３基地局１２Ｃと移動局１０との距離と、第１基地局１２Ａと移動局１０との距離との差を、Ｒ_４１は、第４基地局１２Ｄと移動局１０との距離と、第１基地局１２Ａと移動局１０との距離との差をそれぞれ表わす。 Specifically, the TDOA positioning unit 74 calculates the position of the mobile station 10 as follows. First, Ts is eliminated from the equation (1) to obtain the following equation (2). Specifically, any one of the formulas constituting the formula (1) (the first formula in the present embodiment) is selected, and the square root of both sides thereof is taken as the rest of the formula (1). This is subtracted from the square root of each side of the equation (the second to fourth equations in this embodiment). Here, each equation constituting the equation (1) corresponds to each of the base stations 12 selected by the base station selection unit 80. Preferably, the equation (1) selected is Any one of the formulas constituting the error corresponds to the base station (hereinafter referred to as “reference base station”) having the smallest error obtained by the correlation value error conversion unit 68, that is, the value of the standard deviation of the jitter amount. It is an expression. That is, in the present embodiment, the first base station 12A is the base station having the smallest standard deviation of the jitter amount among the first base station 12A to the fourth base station 12D.

Here, in Equation (2), R ₂₁ represents the difference between the distance between the second base station 12B and the mobile station 10 and the distance between the first base station 12A and the mobile station 10. Similarly, _{R 31} is a distance between the mobile station 10 and the third base station 12C, the difference between the distance between the mobile station 10 and the first base station _{12A, R 41} is a fourth base station 12D moving The difference between the distance to the station 10 and the distance between the first base station 12A and the mobile station 10 is shown.

FIG. 9 illustrates the relationship of the expression (1). In FIG. 9, the arrangement of base stations 12 is different from the arrangement of base stations 12 in FIG. In FIG. 9, r _{1 to} r ₄ represent the distance between each of the first base station 12A to the fourth base station 12D and the mobile station 10, and correspond to the square root of the right side of each of the equations (1). It is. That is, the calculation of the solution of equation (1) is performed by using a circle with a radius r ₁ centered on the first base station 12A, a circle with a radius r ₂ centered on the second base station 12B, and a third base station 12C in FIG. circle of radius r ₃ around the, and calculates the intersection of the circle of radius r ₄ around the fourth base station 12D. On the other hand, since the expression (1) is transformed into the expression (2), the expression (2) does not include Ts, and therefore, the transmission time of the radio wave at the mobile station 10 is required. Therefore, the position of the mobile station 10 can be calculated without any need to consider the error between the clock time of the mobile station 10 and the clock time of each base station 12.

  The TDOA positioning unit 74 obtains the unknowns x and y by solving the equation (2). This equation (2) can be solved by using a solution method such as Newton's method. As shown in the equations (1) and (2), when the mobile station 10 moves in a two-dimensional plane, the solution of the equation (2) is obtained, so that at least three base stations 12 It is necessary to receive radio waves from the mobile station 10.

のように連立方程式が得られる。ここで、ΔＲ_２１、ΔＲ_３１、およびΔＲ_４１は前記（３）で算出されており、また、（∂Ｒ_２１／∂ｘ）、（∂Ｒ_３１／∂ｘ）、（∂Ｒ_４１／∂ｘ）、および（∂Ｒ_２１／∂ｙ）、（∂Ｒ_３１／∂ｙ）、（∂Ｒ_４１／∂ｙ）はＲ_２１、Ｒ_３１、Ｒ_４１をそれぞれｘおよびｙで偏微分することによって得られる。これをΔｘおよびΔｙについて解く。
（５）得られたΔｘおよびΔｙに基づいて初期値ｘ^０およびｙ^０を
ｘ^１＝ｘ^０＋Δｘ，ｙ^１＝ｙ^０＋Δｙ
のようにｘ^１およびｙ^１に更新する。
（６）前記（２）乃至（５）を新たな初期値により実行する。これを（４）において算出されるΔｘおよびΔｙの値が十分小さい値となるまで反復する。 In this Newton method, the solution of equation (2) is calculated by the following procedure.
(1) to determine the appropriate initial value ^{x 0} and ^{y 0.}
(2) the location of the mobile station 10 x, as the _{R 21,} the value corresponding to _{R 31,} and _{R 41} when the initial values ^x 0, ^{y 0} and ^{_{y, R 21 0, R 31}} 0, and R ₄₁ ⁰ is calculated by substituting x ⁰ , y ⁰ into the equation (2).
(3) and the actual value of the _{R 21, R 31,} and _{R 41} actual calculated based on the reception time Tr _i of a radio wave from the mobile station detected in each base station 12i, in (2) Based on the calculated values of R ₂₁ ⁰ , R ₃₁ ⁰ , and R ₄₁ ⁰ , the residuals ΔR ₂₁ , ΔR ₃₁ , and ΔR ₄₁ are
ΔR ₂₁ = _{R 21 -R 21} ⁰
ΔR ₃₁ = _{R 31 -R 31} ⁰
ΔR ₄₁ = R ₄₁ −R ₄₁ ⁰
Calculate as follows.
(4) The initial values x ⁰ and y ⁰ determined in (1) are corrected by an amount corresponding to the residuals ΔR ₂₁ , ΔR ₃₁ , and ΔR ₄₁ calculated in (3). Here, the correction amount for x ⁰ [Delta] x, when the correction amount for y ⁰ and [Delta] y,

The simultaneous equations are obtained as follows. Here, [Delta] R _21, [Delta] R _31, and [Delta] R ₄₁ are calculated by the (3), _{also, (∂R 21 / ∂x),} (∂R 31 / ∂x), (∂R 41 / ∂x ), And (∂R ₂₁ / ∂y), (∂R ₃₁ / ∂y), and (∂R ₄₁ / ∂y) are obtained by partial differentiation of R ₂₁ , R ₃₁ , and R ₄₁ with x and y, respectively. It is done. This is solved for Δx and Δy.
(5) Based on the obtained Δx and Δy, the initial values x ⁰ and y ⁰ are changed to x ¹ = x ⁰ + Δx, y ¹ = y ⁰ + Δy
Updated to ^{x 1} and ^{y 1} as.
(6) The above (2) to (5) are executed with new initial values. This is repeated until the values of Δx and Δy calculated in (4) become sufficiently small values.

のようにベクトル表記を定義すると、前記式（３）は、

のように書き表される。ここで、行列Ｇは、

である。移動局１０の測位に用いられる基地局１２の数が、その測位に用いられる最小の基地局１２の数よりも多い場合には、一般的に前記式（４）の解を最小二乗法に得ることが行なわれる。すなわち、

として、ΔｘおよびΔｙを求めることができる。 here,

When the vector notation is defined as follows, the equation (3) is

It is written as Here, the matrix G is

It is. When the number of base stations 12 used for positioning of the mobile station 10 is larger than the number of minimum base stations 12 used for the positioning, the solution of the above equation (4) is generally obtained by the least square method. Is done. That is,

As Δx and Δy can be obtained.

ここで、σ_ｉ（ｉ＝１〜Ｎ）（Ｎは前記基地局選択部８０により選択された移動局１０の測位に用いられる基地局の数から１を引いた数。）は、各基地局１２のうち前記基準基地局以外における前記ジッタ量の標準偏差の値である。この重み行列生成部７２が重み行列生成部に対応する。具体的には、本実施例における重み行列Ｗは、

のようになる。 When the number of base stations used for positioning selected by the base station selection unit 80 exceeds the minimum number necessary for positioning of the mobile station 10, the weight matrix generation unit 72 uses the base station 12 used for positioning. A weighting matrix W for performing the respective weighting is calculated. This weight matrix W is used in the calculation of the position of the mobile station 10 by the TDOA positioning unit 74. This weight matrix W is calculated based on the standard deviation value of the amount of jitter, which is an error calculated in the correlation value error conversion unit 68 of each base station 12 described above. The weight matrix W indicates that when the wireless communication from the mobile station 10 to the base station 12 includes an error, the reception result at the base station 12 with the large error lowers the weight in calculating the position of the mobile station 10, while The result of reception at the base station 12 with a small error improves the accuracy of the calculated position of the mobile station 10 by increasing the weight in the calculation of the position of the mobile station 10. Specifically, the weight matrix W is defined as follows, for example.

Here, σ _i (i = 1 to N) (N is the number obtained by subtracting 1 from the number of base stations used for positioning of the mobile station 10 selected by the base station selection unit 80). 12 is a standard deviation value of the jitter amount other than the reference base station. The weight matrix generation unit 72 corresponds to the weight matrix generation unit. Specifically, the weight matrix W in this embodiment is

become that way.

これにより、前記複数の基地局１２のそれぞれの重みを考慮して、ΔｘおよびΔｙを求めることができる。 Thus, when the weight matrix W is calculated in the weight matrix generation unit 72, the TDOA positioning unit 74 calculates the position of the mobile station 10 in consideration of the weight matrix W. By calculating the position of the mobile station 10 in consideration of the weight matrix W, based on the standard deviation value of the amount of jitter, which is an error calculated in the correlation value error conversion unit 68 of each base station described above. The reception result at the base station 12 having a large error included in the wireless communication from the mobile station 10 to the base station 12 lowers the weight in calculating the position of the mobile station 10, while the reception result at the base station 12 having a small error is The position of the mobile station 10 can be calculated by increasing the weight in the calculation of the position of the mobile station 10. When this weight matrix W is considered in the above equation (5), the following equation (6) is obtained.

Accordingly, Δx and Δy can be obtained in consideration of the weights of the plurality of base stations 12.

  The TDOA positioning unit 74 calculates the position of the mobile station 10 as described above. The TDOA positioning unit 74 corresponds to the positioning unit. FIG. 10 illustrates the calculation of the peak value of the correlation value in the correlation value calculation unit 64 of the mobile station 12, the calculation of the standard deviation of the jitter amount as the error in the correlation value error conversion unit 68 of the mobile station 12, The relationship between calculation of the weight matrix W in the weight matrix generation part 72 and calculation of the position of the mobile station 10 in the above-mentioned TDOA positioning part 74 is demonstrated. As shown in FIG. 10, in the mobile station positioning system of the present embodiment, based on the magnitude of the peak value of the correlation value, which is a detectable amount, the magnitude of the peak value of the correlation value is negatively correlated. A standard deviation of a certain amount of jitter is estimated for each base station 12 based on a relationship obtained in advance. Then, using the estimated standard deviation of the amount of jitter, a weight matrix W defining weights in calculating the position of the mobile station 10 of each base station 12 is calculated, and using the calculated weight matrix W, the mobile station 10 The position of is calculated.

  FIG. 11 is a flowchart for explaining an example of the control operation of the mobile station positioning system 6 of the present invention. First, in step SA1 (hereinafter, “step” is omitted) corresponding to the base station radio unit 32, the mobile station radio unit 22 and the like, establishment of communication performed between the mobile station 10 and each base station 12 is established. Done. Specifically, for example, a channel (frequency) used for communication in the mobile station 10 and each base station 12 is determined, and each base station 12 starts receiving a radio wave transmitted from the mobile station 10.

  In SA2 corresponding to the mobile station radio unit 22 of the mobile station 10, radio waves for positioning are transmitted from the mobile station 10. The radio wave for positioning includes a spread code for detecting the reception time. The transmission of radio waves for positioning from the mobile station 10 may be performed periodically, for example, at predetermined time intervals, or radio waves may be transmitted from the positioning server 14 or any of the base stations 12. It may be performed when a command is issued.

  In SA3 corresponding to the base station radio unit 32 of each base station 12, reception of radio waves for positioning transmitted from the mobile station 10 is started, and received radio waves are decoded and received. The spreading code contained in the received radio wave is extracted. The reception of this radio wave is executed in each base station 12 until, for example, an error is calculated in SA5 described later.

  In SA4 corresponding to the correlation value calculation unit 64 and the peak time detection unit 70 of the base station 12, the correlation between the code extracted from the radio wave from the mobile station 10 whose reception is started in SA3 and the replica code stored in advance. A value is calculated. This replica code is the same code as the spreading code included in the radio wave transmitted from the mobile station 10 in SA2. Further, since the correlation code produces a sharp peak only when the spreading code is in phase, the replica code and the code extracted from the radio wave started to be received in SA3 are in phase. That is, when synchronized, the correlation value peaks. In step SA4, the peak value is detected, and the time at which the peak value is detected is detected as a synchronization time (reception time) by referring to the clock 40 of the mobile station 12, for example. Information about the reception time calculated in this step is transmitted to the positioning server 14 via the communication cable 20, for example.

  In SA5 corresponding to the correlation value error conversion unit 68, the magnitude of the peak value of the correlation value calculated in SA4 is converted into a standard deviation value of the amount of jitter as the corresponding error. In this conversion, for example, the magnitude of the peak value of the correlation value calculated in SA4 from the relation storage unit 66 that stores in advance information about the magnitude of the standard deviation of the jitter amount corresponding to the peak value of the correlation value. This is performed by reading the standard deviation value of the amount of jitter corresponding to. Information about the magnitude of the standard deviation of the jitter amount calculated in this step is transmitted to the positioning server 14 via the communication cable 20, for example.

  In SA6, the calculation of the peak value of the correlation value in SA4 and the calculation of the standard deviation of the jitter amount in SA5 are performed in all the base stations 12 that have received the positioning radio waves transmitted from the mobile station 10 in SA2. It is determined whether or not. If these values are not calculated in all base stations, the determination in this step is denied, and SA4 and SA5 are executed for the base stations for which values have not yet been calculated. On the other hand, when the value is calculated in all the base stations, the determination in this step is affirmed and SA7 is executed.

  In SA7 corresponding to the base station selection unit 80 and the weight matrix generation unit 72 of the positioning server 14, among all the base stations 12 in which reception of radio waves for positioning transmitted from the mobile station 10 is started in SA3, Based on the standard deviation of the jitter amount for base stations other than the reference base station, a weight matrix W for determining weights in positioning of the base stations 12 is calculated.

  In SA8 corresponding to the TDOA positioning unit 74 of the positioning server 14, the reception time in each base station 12 calculated in SA4, the position of each base station 12 that is known in advance, and the weight matrix W generated in SA7 The position of the mobile station 10 is calculated based on the information. Specifically, the position of the mobile station 10 is obtained as a solution by solving the above equation (2) by the Newton method.

  According to the mobile station positioning system 6 of the above-described embodiment, the correlation value calculation unit 64 (SA4) calculates the correlation value between the spread code included in the radio waves received by the plurality of base stations 12 and the replica code. The magnitude is calculated based on a predetermined relationship, and the correlation value error conversion unit 68 (SA5) transmits the magnitude of the correlation value calculated in advance and each of the plurality of base stations 12 transmitted from the mobile station 10. Based on the magnitude of the correlation value calculated by the correlation value calculation unit 64 from the relationship stored in the relationship storage unit 66 in advance with the error-related value related to the communication error in the wireless communication of the spreading code received by An error-related value related to a communication error in wireless communication from the mobile station 10 to each of the plurality of base stations 12 is calculated for each of the plurality of base stations 12; The amount of jitter, which is the error-related value in wireless communication from the mobile station 10 to each of the plurality of base stations 12, calculated by the correlation value error conversion unit 68 by the weight matrix generation unit 72 (SA7) Based on the standard deviation, a weight matrix W representing weights in positioning of each of the plurality of base stations is determined based on a pre-stored relationship, and the TDOA positioning unit 74 determines the radio waves transmitted from the mobile station 10. Using the reception results at each of the plurality of base stations 12 when the plurality of base stations 12 have received, the positions of these base stations 12, and the weight matrix W generated by the weight matrix generation unit 72, Since the position of the mobile station 10 is calculated by the equation (2) which is a pre-stored relationship, a radio wave including a spread code transmitted from the mobile station 10 is received. Calculation of the position of the mobile station 10 in consideration of the weights for each of the plurality of base stations 12 is performed. Further, when calculating the position of the mobile station 10 using the weights, the amount of calculation does not increase even if the number of base stations 12 increases, or the mobile station does not increase in size or cost. The mobile station positioning system 6 that can perform positioning of the mobile station 10 with high accuracy can be provided.

  Further, according to the mobile station positioning system 6 of the above-described embodiment, all the radio waves received from the mobile station 10 that are the targets of positioning among the plurality of base stations by the base station selection unit 80 are received. The base station 12 is selected as the selected base station used for positioning of the mobile station 10, and the reception result of the radio wave at the selected selected base station, that is, the jitter corresponding to the reception time and the peak value of the correlation value Since the position of the mobile station 10 is calculated based on the standard deviation of the quantity, the calculated mobile station is calculated by calculating the position of the mobile station 10 based on the reception results of more base stations 12. The accuracy of the 10 positions can be improved.

  Further, according to the mobile station positioning system 6 of the above-described embodiment, the base station 12 detects the reception time of radio waves based on the time when the peak of the correlation value calculated by the correlation value calculation unit 64 occurs. The TDOA positioning unit 74 calculates the position of the mobile station 10 based on the reception time detected by the peak time detection unit 70 of each of the plurality of selected base stations 12. Therefore, the reception time can be detected accurately based on the change of the correlation value calculated by the correlation calculation unit 64, that is, the occurrence of a peak.

  Further, according to the mobile station positioning system 6 of the above-described embodiment, the base station 12 is configured to include the correlation value error conversion unit 68 and the relationship storage unit 66. Based on the correlation value calculated by the value calculation unit 64, a standard deviation of the amount of jitter as the error-related value can be calculated.

  Subsequently, another embodiment of the present invention will be described. In addition, about the part which is common between Example, the same code | symbol is attached | subjected and description is abbreviate | omitted.

  The present embodiment relates to the configuration of the base station 12 and the positioning server 14 and a modification of the functions thereof. FIG. 12 is a diagram for explaining the outline of the functions of the electronic control device 33 of the base station 12, and corresponds to FIG. 4 in the first embodiment. 12 is compared with FIG. 4 in that the electronic control device 33 of the base station 12 according to the present embodiment does not have the correlation value error conversion unit 68 and the relationship storage unit 66.

  On the other hand, FIG. 13 is a diagram for explaining an overview of the functions of the electronic control device 48 of the positioning server 14 and corresponds to FIG. 8 in the first embodiment. Comparing FIG. 13 and FIG. 8, the electronic control device 48 of the positioning server 14 of the present embodiment is different in that it includes a correlation value error conversion unit 168 and a relationship storage unit 166.

  In FIG. 13, the relationship storage unit 166 stores the same information as that stored in the relationship storage unit 66 in the first embodiment, that is, the peak value of the correlation value calculated by the correlation value calculation unit 64. As shown in FIG. 6, the standard deviation value of the jitter amount is associated as the standard deviation value of the error in the detection of the synchronization time detected by the peak time detection unit 70 corresponding to the magnitude of the peak value. Remember.

  Similarly to the correlation value error conversion unit 68 in the first embodiment, the correlation value error conversion unit 168 uses the information stored in the relationship storage unit 166 and the correlation value calculated by the correlation value calculation unit 64. Based on the information about the peak value, a standard deviation of the jitter amount, which is an error value corresponding to the peak value of the correlation value, is calculated. The correlation value error conversion unit 68 corresponds to the correlation value error conversion unit.

  Thus, in the present embodiment, the correlation value error conversion unit 68 and the relationship storage unit 66 that the electronic control device 33 of the base station 12 had in the above-described embodiment are replaced by the electronic control device 48 of the positioning server 14. The correlation value error conversion unit 168 and the relationship storage unit 166 have similar functions.

  Since the electronic control device 33 of the base station 12 and the electronic control device 48 of the positioning server 14 are configured as described above, the correlation value calculated by the correlation value calculation unit 64 is transmitted from each base station 12 to the positioning server 14. Information on the peak value and information on the reception time detected by the peak time detection unit 70 are transmitted.

  In the mobile station positioning system 6 in the present embodiment, the operation is performed according to the procedure shown in the flowchart of FIG. 11, for example, as in the first embodiment, but the operation of SA5 corresponding to the correlation value error conversion unit 168 is as follows. The point performed by the positioning server 14 is different from the flowchart of FIG. 11 in the above-described embodiment. Accordingly, the positioning server 14 also determines whether the error, that is, the standard deviation of the amount of jitter has been calculated for all the base stations of SA6.

  According to the mobile station positioning system 6 of the above-described embodiment, since the positioning server 14 includes the correlation value error conversion unit 116 and the relationship storage unit 166, in addition to the effects of the above-described first embodiment. The positioning server 14 can collectively execute the calculation associated with the calculation of the error-related value for each base station 12, that is, the standard deviation of the amount of jitter.

  In the present embodiment, a combination of base stations used for positioning of the mobile station 10 is selected, and positioning of the mobile station 10 is performed using the base stations 12 constituting the selected combination. FIG. 14 is a diagram for explaining the mobile station positioning system 160 according to the present embodiment. The mobile station 10 and the predetermined area 8 in which the mobile station 10 is movable and a plurality of base stations 101 to 135 are illustrated. It is a figure explaining an example of arrangement | positioning. In FIG. 14, the description of the communication server 20 that connects the positioning server 14 and each of the base stations 101 to 135 and the positioning server 14 so that information communication is possible is omitted.

  If the area 8 in which the mobile station 10 can move exceeds the distance in which the mobile station 10 and the base station can communicate, that is, the area where the radio wave transmitted from the mobile station 10 reaches, the area 8 is transmitted from the mobile station 10 It is required to arrange the base stations so that radio waves for positioning are received by at least the minimum number of base stations necessary for positioning. In addition, since a radio wave including a command for controlling the operation of the mobile station 10 is transmitted from the base station to the mobile station 10, that is, if the radio wave transmitted from the mobile station 10 exceeds the reachable area, The radio wave transmitted from the base station to the mobile station 10 can be received by the mobile station 10 even if the mobile station 10 exists at any position in the region 8 where the mobile station 10 can move. It is required to arrange base stations in the same way.

  FIG. 14 is a diagram for explaining an example of the arrangement of base stations to satisfy such a request. In FIG. 14, among the plurality of base stations 101 to 135, these base stations 101 to 135 have the configurations and functions shown in FIGS. 3 and 4, for example, as described in the first embodiment. . That is, a positioning radio wave transmitted from the mobile station 10 is received, the reception time is calculated by the peak time detection unit 70 as the reception result, and the standard deviation of the jitter amount is calculated by the correlation value error conversion unit 68 Then, information about these calculated values is transmitted to the positioning server 14. In addition to these functions, the control base stations 107, 109, 117, 119, 127, and 129 among the plurality of base stations 101 to 135 operate the mobile station 10 with respect to the mobile station 10 by the base station control unit 62. An operation for transmitting a radio wave including a command for controlling the signal is performed. In FIG. 14, circles R1 to R6 represent the reach of radio waves transmitted from the control base stations 107, 109, 117, 119, 127, and 129, respectively. As shown in FIG. 14, the area 8 in which the mobile station 10 can move is included in a range where radio waves transmitted from any of the six control base stations 107, 109, 117, 119, 127, and 129 reach. The radio wave transmitted from at least one of the control base stations 107, 109, 117, 119, 127, and 129, regardless of where the mobile station 10 is located in the movable region 8, Can be received.

  In the present embodiment as well, the mobile station 10 having the configuration and functions shown in FIG. 2 is used as in the first embodiment.

  FIG. 15 is a functional block diagram for explaining the functions of the electronic control device 48 of the positioning server 14 constituting the mobile station positioning system 160 of this embodiment. As the configuration of the positioning server 14, the configuration shown in FIG. 7 is specifically used as in the first embodiment.

  In FIG. 15, base station setting section 176 includes control base station selection section 178 and base station selection section 180, and sets a base station used for calculating the position of mobile station 10 in TDOA positioning section 74.

  Among these, the control base station selection unit 178 selects a selection control base station that actually performs communication with the mobile station 10 such as instructing the mobile station 10 to control its operation from the control base stations. To do. In the present embodiment, six control base stations 107, 109, 117, 119, 127, and 129 are provided as described above, and one of these control base stations is selected as the selected control base station. . Specifically, for example, the control base station selection unit 178 causes one control base station selected from the six control base stations in a predetermined order to execute an operation for establishing communication with the mobile station 10, First, the control base station that has successfully established communication with the mobile station 10 is defined as a selection control base station that performs communication with the mobile station 10. Here, the predetermined order may be, for example, the order in which the codes given to the control base stations are small, that is, the order of 107, 109, 117, 119, 127, and 129.

  The base station information storage unit 177 stores information about combinations of base stations set in advance for each control base station. This combination is a combination of base stations used for calculating the position of the mobile station 10 by the TDOA positioning unit 74 together with the selected control base station when each control base station is selected as the selected control base station. FIG. 16 is a diagram for explaining an example of information stored in the base station information storage unit 177. For the code of each control base station, the TDOA positioning unit 74 together with the selected control base station sets the mobile station 10's code. The code | symbol of the base station which comprises the base station group which is a combination of the base station used for calculation of a position is described. For example, when the control base station 107 is a selection control base station, a combination of base stations (base station group) including the base stations 101, 102, 103, 106, 107, 108, 111, 112, and 113 is used. And stored so as to calculate the position of the mobile station 10.

  The base station selection unit 180 of the present embodiment is operated by a different operation from the base station 80 in the first embodiment described above, that is, information on the selected control base station selected by the control base station selection unit 178, and Based on the information stored in the base station information storage unit 177, the TDOA positioning unit 74 selects a selected base station that is a base station used for calculating the position of the mobile station 10. Specifically, the control base station selection unit 178 selects from the information about the base stations constituting the base station group corresponding to each control base station stored in the base station information storage unit 177. The selected base station is selected by reading out information on base stations constituting the base station group corresponding to the selected control base station.

  Further, the weight matrix generation unit 72 and the TDOA positioning unit 74 perform the same operations as in the above-described embodiment, and thus the description thereof is omitted.

  FIG. 17 is a flowchart illustrating an example of the control operation of the base station setting unit 176 in the present embodiment. This flowchart is executed, for example, in place of SA1 in the flowchart of FIG. 11 representing an example of the control operation of the mobile station positioning system 6 described in the first embodiment.

  SB1 to SB3 correspond to the control base station selection unit 178. First, in SB1, an operation for establishing communication between the control base station i and the mobile station 10 for one control base station i among the plurality of control base stations according to a predetermined order. Is done. Here, as described above, the predetermined order is, for example, the order in which the codes attached to the control base station are in the ascending order. In this case, for the control base station 107, first, establishment of communication with the mobile station 10 is established. The operation for is performed.

  In the subsequent SB2, it is determined whether or not communication has been established between the control base station i and the mobile station 10 performed in SB1. If communication is established, the determination in this step is affirmed and SB3 is executed. On the other hand, if communication is not established, the mobile station 10 is not within the reach of the radio wave transmitted by the control base station i, the determination of this step is denied, and SB5 is executed. In SB5, 1 is added to the value of i, and SB1 and subsequent steps are executed again. That is, the establishment of the communication is attempted for another control base station i + 1. For example, when the mobile station 10 is at the position shown in FIG. 14, the mobile station 10 is located inside the circle R 1 that is the reach of the radio wave transmitted from the control base station 107. 10 is established, and the determination in this step is affirmed.

  In SB3 that is executed when the determination of SB2 is affirmed, the control base station that has been determined in SB2 that communication with mobile station 10 has been established in SB2 actually performs communication with mobile station 10 Selected as the selection control base station. For example, when communication between the control base station 107 and the mobile station 10 is established in SB2, the control base station 107 is selected as the selection control base station.

  In SB4 corresponding to the base station selection unit 180, selection is made in the SB3 from information on base stations constituting the base station group corresponding to each control base station stored in the base station information storage unit 177. Information about base stations constituting the base station group corresponding to the selected control base station is read, and the base stations constituting the base station group are selected as the selected base station. For example, in SB3, when the control base station 107 is selected as the selected control base station, for example, information stored in the base station information storage unit 177 (see FIG. 16) is stored corresponding to the control base station 107. Information about the base station group is read, and base stations 101, 102, 103, 106, 107, 108, 111, 112, and 113 that form the base station group are used for calculating the position of the mobile station 10 Selected as a station.

  After the flowchart of FIG. 17 is executed, SA2 and subsequent steps in the flowchart of FIG. 11 are performed, and a control operation for positioning of the mobile station 10 is executed. Among these, in SA2 corresponding to the mobile station radio unit 22 and the like of the mobile station 10, the positioning of the mobile station 10 is determined based on a command transmitted from the control base station selected as the selection control base station in the SB3, for example. For this purpose, radio waves are transmitted. The radio wave for positioning includes a spread code for detecting the reception time.

  Since the steps after SA3 are the same as those in the above-described embodiment, the description thereof is omitted. In the present embodiment, the operation of SA3 to SA6 is different from the above-described embodiment in that it is executed only for a base station selected as a selected base station that is a base station used for positioning in SB4. That is, in the base stations other than the selected base station selected in SB4, it is not necessary to perform operations such as reception of radio waves from the mobile station 10 and detection of the reception time. Therefore, the weight matrix calculated in SB7 is the weight of the base station selected as the selected base station that is the base station used for positioning in SB4, and the calculation of the position of the mobile station 10 in SA8 is selected in SB4. This is performed using only the selected base station.

  According to the mobile station positioning system 6 of the above-described embodiment, the plurality of base stations 101 to 135 have a plurality of control bases capable of performing wireless communication with the mobile station in order to control the operation of the mobile station 10. Stations 107, 109, 117, 119, 127, and 129, and the control base station selection unit 178 (SB1 to SB3), from among the plurality of control base stations 107, 109, 117, 119, 127, and 129, A control base station that establishes wireless communication with the mobile station 10 is selected as a selection control base station that controls the operation of the mobile station, and is selected by the control base station selection unit 178 by the base station selection unit 180 (SB4). Information about the selected selected control base station and the plurality of control base stations 107, 109, 117, 119, 127, 1 stored in the base station information storage unit 177 in advance. When each of 9 is the selection control base station, the control is performed based on information on a combination (base station group) of base stations to be selected base stations that are base stations used for positioning of the mobile station. The selected base station, which is a base station used for positioning of the mobile station 10, is selected from the plurality of base stations 101 to 135 for the selected control base station selected by the base station selection unit 178. Since the position of the mobile station 10 is calculated using the selected base station selected in this way, in addition to the effect of the above-described embodiment, the mobile station 10 is transmitted from the mobile station 10 when the distance to the mobile station 10 is long. By calculating the position of the mobile station 10 using the reception result of the base station where the radio waves for positioning are not received well, it is possible to prevent the accuracy of the calculated position of the mobile station 10 from deteriorating.

  In addition, when there are a plurality of mobile stations 10, one mobile station 10 is located at the same time as positioning of one mobile station 10 using a certain control base station and a base station group corresponding to the control base station. Positioning of another mobile station 10 can be performed using another control base station that is not used for positioning and a base station group corresponding to the control base station.

  In the present embodiment, a plurality of base stations 12 receive radio waves transmitted by the mobile station 10 and measure the reception strength thereof. Based on the measured reception strength, each of the mobile station 10 and the plurality of base stations 12 is measured. And a positioning method for calculating the position of the mobile station 10 using the calculated distance.

  In the above-described embodiment, the TDOA positioning unit 74 determines the reception time of the radio wave transmitted from the mobile station 10 detected by the peak time detection unit 70 of the plurality of base stations 12 and the positions of the plurality of base stations 12. Based on the above information, the position of the mobile station 10 was calculated by solving the above equation (1). In this method, each base station 12 has a peak time detection unit 70 and needs to detect the reception time of the radio wave from the mobile station 10. In order to perform the calculation in the peak time detection unit 70 with high accuracy. May require high-performance hardware such as an electronic control unit that operates with a high clock.

  By the way, it is known that the received power when a radio wave transmitted with a predetermined transmission power is received has a certain relationship with the propagation distance of the radio wave. That is, if a radio wave for positioning is transmitted from the mobile station 10 with a predetermined transmission power, the received power is measured at each base station 12 that has received the radio wave, based on the predetermined relationship. The distance between the mobile station 10 and each base station 12 can be estimated. As described above, if the distance between the mobile station 10 and each base station 12 is estimated, the equation corresponding to the equation (1) is detected without detecting the reception time of the radio wave from the mobile station 10 in each base station 12. And the position of the mobile station 10 can be calculated by solving this.

  In the present embodiment, the mobile station 10 having, for example, the configuration shown in FIG. 2 is used as in the above-described embodiment. Further, the base station 12 has the configuration shown in FIG. 3, for example, as in the above-described embodiment.

  FIG. 18 is a functional block diagram for explaining an overview of the functions of the electronic control device 33 of the base station 12 according to the present embodiment. As shown in FIG. 18, the electronic control unit 33 includes a base station control unit 34, a correlation value calculation unit 64, a reception intensity detection unit 171, a reception intensity distance conversion unit 172, and a reception intensity distance relationship storage unit 173. Among these, the base station control unit 34 and the correlation value calculation unit 64 operate in the same manner as in the above-described embodiment, and thus description thereof is omitted.

  The reception strength detection unit 171 is an RSSI (Receive Signal Strength Indicator) that is an index obtained by quantifying the reception strength of the radio wave for positioning transmitted from the mobile station 10 received by the base station radio unit 32 of the base station 12. ) Is detected. This RSSI is, for example, an index for evaluating the reception intensity of radio waves in, for example, 256 levels, and has a one-to-one relationship with the reception power PR. The reception intensity detection unit 171 corresponds to the reception intensity detection unit.

The reception intensity distance relationship storage unit 173 stores the relationship between the RSSI in the base station 12 and the distance between the mobile station 10 and the base station 12 when the mobile station 10 transmits radio waves with a predetermined output. In general, the transmission power PT (dBm), the reception power PR (dBm), and the radio wave propagation distance D (m) are:
PR = −20 log (4πDf / c) + GTA + GRA + PT (7)
There is a relationship. Here, f is a radio wave frequency (Hz), c is a radio wave velocity, GTA is a transmission antenna gain (dBi), and GRA is a reception antenna gain (dBi). The reception intensity distance relation unit 173 stores the equation (7) together with parameters of the transmission power PT, the radio wave frequency f, the radio wave speed c, the transmission antenna gain GTA, and the reception antenna gain GRA. FIG. 19 illustrates an example of the relationship of the equation (7), and the reception intensity distance relationship unit 173 may store such illustrated relationship as a map.

  Based on the RSSI as the reception strength measured by the reception strength detection unit 171 and the relationship stored in the reception strength distance relation storage unit 173, the reception strength distance conversion unit 172 performs the reception strength distance conversion unit 172. The distance between the mobile station 10 and the base station 12 corresponding to the RSSI as the measured reception intensity is calculated. Specifically, for example, when the equation (7) is stored together with the parameter in the reception intensity distance relation storage unit 173, the RSSI measured by the reception intensity detection unit 171 is converted into the reception power PR. Then, the received power PR is substituted into the equation (7), and the propagation distance of the radio wave, that is, the distance from the mobile station 10 to the base station 12 is calculated. Alternatively, when the relationship as shown in FIG. 19 is stored as a map in the reception intensity distance relationship storage unit 173, the propagation distance of radio waves corresponding to the RSSI measured by the reception intensity detection unit 171, ie, movement The distance from the station 10 to the base station 12 is extracted from the relationship shown in FIG.

  Information about the peak value of the correlation value and the distance value between the mobile station 10 and the base station 12 detected and calculated in this way by the base station 12 is transmitted from the base station control unit 34 to the communication interface 46. Via the positioning server 14.

  In the present embodiment, as the positioning server 14, for example, the one having the configuration shown in FIG. 7 is used as in the above-described embodiment. FIG. 20 is a functional block diagram for explaining an overview of the functions of the electronic control device 48 of the positioning server 14. As illustrated in FIG. 20, the electronic control device 48 of the positioning server 14 includes a correlation value error conversion unit 168, a relationship storage unit 166, a second weight matrix generation unit 73, and an RSSI positioning unit 174.

  Among these, the correlation value error conversion unit 168 and the relationship storage unit 166 operate in the same manner as described in the second embodiment, that is, the peak value of the correlation value calculated by the correlation value calculation unit 64 of each base station 12. Based on this, an operation for calculating the standard deviation of the amount of jitter corresponding to the peak value is performed.

  Further, the second weight matrix generation unit 73 is the same as that described in the first embodiment based on the standard deviation value of the jitter amount calculated for each base station 12 by the correlation value error conversion unit 168. The weighting matrix W for performing weighting of each base station 12 by operation is calculated. The second weighting matrix generation unit 73 generates a weighting matrix by using all base stations used for positioning. Different from the part 72. The weight matrix W generated by the second weight matrix generation unit 73 is used in the calculation of the position of the mobile station 10 by the RSSI positioning unit 174 described later. The weight matrix W in the first to third embodiments described above. Is calculated in the same manner as That is, the weight matrix W reduces the weight in the calculation of the position of the mobile station 10 when the wireless communication from the mobile station 10 to the base station 12 includes an error and the reception result at the base station 12 with the large error is On the other hand, the reception result at the base station 12 having a small error improves the accuracy of the calculated position of the mobile station 10 by increasing the weight in the calculation of the position of the mobile station 10.

The RSSI positioning unit 174 calculates the distance between each base station 12 and the mobile station 10 calculated by the reception intensity distance conversion unit 172 of each base station 12, and the position of each base station 12 that is known in advance. And the position of the mobile station 10 are calculated based on the information on the weight matrix W and the information on the weight matrix W generated by the weight matrix generator 72 (RSSI method). The coordinates of the mobile station are (x, y), the coordinates indicating the position of the first base station 12A are (x _B1 , y _B1 ), the coordinates of the second base station 12B are (x _B2 , y _B2 ), and the third base When the coordinates of the station 12C are (x _B3 , y _B3 ) and the coordinates of the fourth base station 12D are (x _B4 , y _B4 ), the position of the mobile station is expressed by the following equation (8). Here, the coordinates of the base station 12 and the mobile station 10 are represented by a coordinate system defined as shown in FIG. 1, for example.
(x _B1 −x) ² + (y _B1 −y) ² = D ₁
(x _B2 −x) ² + (y _B2 −y) ² = D ₂
(x _B3 −x) ² + (y _B3 −y) ² = D ₃
(x _B4 −x) ² + (y _B4 −y) ² = D ₄ … (8)
Here, D _{1 to} D ₄ (m) are the distances between the first base station 12A to the fourth base station 12D and the mobile station 10, respectively, and are the first base station 12A to the fourth base station 12D. This is a value calculated by each received intensity distance conversion unit 172.

  The RSSI positioning unit 174 solves the equation (8) by a solving method such as Newton's method in the same manner as the TDOA positioning unit 74 solves the equation (1) to obtain the position x, y of the mobile station 10. . A specific solution is the same as that in which the TDOA positioning unit 74 solves the equation (1) in the first embodiment, and a description thereof will be omitted. This RSSI positioning unit 174 corresponds to the positioning unit.

  FIG. 21 is a flowchart for explaining an example of the control operation of the mobile station positioning system 6 of the present embodiment, and corresponds to the flowchart of FIG. 11 of the above-described embodiment. Among these, steps (hereinafter, “step” is omitted) SC1 to SC4 correspond to steps SA1 to SA4 in FIG.

  First, in step SC1 corresponding to the base station radio unit 32, the mobile station radio unit 22, and the like, communication established between the mobile station 10 and each base station 12 is established. Specifically, for example, a channel (frequency) used for communication in the mobile station 10 and each base station 12 is determined, and each base station 12 starts receiving a radio wave transmitted from the mobile station 10.

  In the SC 2 corresponding to the mobile station radio unit 22 of the mobile station 10, radio waves for positioning are transmitted from the mobile station 10. The radio wave for positioning includes a spread code for detecting the reception time. The transmission of radio waves for positioning from the mobile station 10 may be performed periodically, for example, at predetermined time intervals, or radio waves may be transmitted from the positioning server 14 or any of the base stations 12. It may be performed when a command is issued.

  In SC3 corresponding to the base station radio section 32 of each base station 12, reception of radio waves for positioning transmitted from the mobile station 10 is started, and received radio waves are decoded and received. The spreading code contained in the received radio wave is extracted. The reception of this radio wave is executed in each base station 12 until, for example, calculation of an error in SC5 described later is performed.

  In SC4 corresponding to the correlation value calculation unit 64 of the base station 12, the correlation value between the code extracted from the radio wave from the mobile station 10 whose reception is started in SC3 and the replica code stored in advance is calculated. This replica code is the same code as the spread code included in the radio wave transmitted from the mobile station 10 in SC2. Further, since the correlation code has a sharp peak only when the spread code has the same phase, the replica code and the code extracted from the radio wave received by the SC3 have the same phase, ie, synchronization. When done, the correlation value peaks. In step SC4, the peak value is detected and transmitted to the positioning server 14 via the communication cable 20, for example.

  In SC5 corresponding to reception intensity detecting section 171 and reception intensity distance converting section 172, the reception intensity of the radio wave started to be received in SC3 is measured, and the distance between mobile station 10 and base station 12 corresponding to the reception intensity is measured. Is calculated. This calculation is performed, for example, using the relationship between the reception intensity and the distance stored in the reception intensity distance relationship storage unit 173.

  In SC6 corresponding to the correlation value error conversion unit 168 of the positioning server 14, the magnitude of the peak value of the correlation value calculated in SC4 is converted into the standard deviation value of the jitter amount as the corresponding error. . This conversion is performed by, for example, the magnitude of the peak value of the correlation value calculated in SC4 from the relation storage unit 166 that stores in advance information about the magnitude of the standard deviation of the jitter amount corresponding to the peak value of the correlation value. This is performed by reading the standard deviation value of the amount of jitter corresponding to.

  In SC7, the calculation of the peak value of the correlation value in SC4, the measurement of the received intensity and the calculation of the distance in SC5 are performed in all the base stations 12 that have received the positioning radio waves transmitted from the mobile station 10 in SC2. Then, it is determined whether or not the standard deviation of the jitter amount in SC6 has been calculated. If these values have not been calculated in all base stations, the determination in this step is denied, and SC4 to SC6 are executed for the base stations for which values have not yet been calculated. On the other hand, when the value is calculated in all the base stations, the determination in this step is affirmed and SC8 is executed.

  In SC8 corresponding to the second weight matrix generation unit 73 of the positioning server 14, the jitter amount standard for all base stations 12 that have started receiving radio waves for positioning transmitted from the mobile station 10 in SC3. Based on the deviation, a weight matrix W for determining weights in positioning of these base stations 12 is calculated.

  In SC9 corresponding to the TDOA positioning unit 74 of the positioning server 14, the distance between the mobile station 10 and each base station 12 calculated based on the reception intensity at each base station 12 measured in SC5 is known in advance. The position of the mobile station 10 is calculated based on the position of each base station 12 and the information about the weight matrix W generated in SC8. Specifically, the position of the mobile station 10 is obtained as a solution by solving the above equation (1) by the Newton method.

  According to the mobile station positioning system 6 of the above-described embodiment, the base station 12 has the reception intensity detection unit 171 (SC5) that detects the reception intensity when the radio wave transmitted from the mobile station 10 is received, The RSSI positioning unit 174 (SC9) determines the position of the mobile station 10 based on the reception strength detected by the reception strength detection unit 171 of each of the plurality of base stations 12 used for positioning of the mobile station 10. Therefore, the position of the mobile station 10 can be calculated based on the reception intensity (RSSI) of the radio wave that can be detected relatively easily, and the weight of each of the base stations 12 is taken into consideration. The position of the station 10 is calculated, and the weight of the base station with a larger communication error with the mobile station 10 is reduced. When calculating the number of base stations 12, the amount of calculation increases even when the number of base stations 12 increases, or the mobile station 10 is positioned with high accuracy without increasing the size and cost of the mobile station 10. Can do. In addition, when a base station 12 is used as a base station 12, a configuration for positioning is simplified when a spreading code is used for communication, such as a wireless LAN, and the reception strength is detected in advance. can do. That is, the mobile station positioning system 6 can be configured using the configuration for the wireless LAN as it is.

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

  In the above-described embodiment, the standard deviation of the jitter amount is used as an error in communication. However, the present invention is not limited to this. For example, there is a correlation with the standard deviation of the jitter amount, that is, other one-to-one relationship. An amount may be used. Specifically, the standard deviation of the reception time detection error and the standard deviation of the distance error between the mobile station 10 and the base station 12 may be used instead of the standard deviation of the jitter amount.

  In the above-described embodiment, the base station selection units 80 and 180 select all the base stations 12 that have received the radio waves transmitted by the mobile station 10 as selected base stations used for calculating the position of the mobile station 10, Alternatively, the base station 12 constituting the combination of base stations (base station group) corresponding to the selected control base station selected by the control base station selection unit 178 is selected as the selected base station. However, the present invention is not limited to such a mode. For example, the base station 12 having a peak value of the correlation value larger than a predetermined value is selected as the selected base station, or the reception strength (RSSI) is set in advance. It is also possible to select a base station 12 larger than a predetermined value as a selected base station.

  Further, in the above-described embodiment, the control base station selection unit 178 causes the one control base station selected from the control base station in a predetermined order to execute the operation of establishing communication with the mobile station 10, The control base station that first successfully established communication with the mobile station 10 was selected as a selective control base station that communicates with the mobile station 10. Here, the predetermined order is the order in which the codes given to the control base stations are small in the above-described embodiment, but is not limited to such an aspect. For example, when the position of the mobile station 10 is repeatedly calculated by the mobile station positioning system 6 in the above-described embodiment, for example, at a predetermined interval, the distance from the position of the mobile station 10 calculated immediately before is calculated. The order from the shortest distance from the nearest control base station may be used.

  Further, in the mobile station positioning system 6 of the above-described third embodiment, the base station setting unit 176 is provided in the server as compared with the first embodiment, but the base station setting is set in the mobile station positioning system 6 of the second embodiment. Of course, the portion 176 can be applied.

  In the above-described embodiment, the server 14 and the base station 12 are connected via the communication cable 20 so as to be capable of information communication. However, this communication is not limited to wired communication but may be wireless communication.

  In the first to third embodiments, when the position of the mobile station 10 is calculated by the TDOA positioning unit 74, the reference base station constituting the equation (1), that is, the standard deviation of the jitter amount is calculated. The expression corresponding to the base station having the smallest value (in the above embodiment, the value obtained by taking the square root of both sides of the first expression is replaced with the remaining expression (the second expression to the second expression in the above embodiment). The equation (2) is obtained from the equation (1) by subtracting from the square root of each side of the equation (4), and the weight matrix generator 72 is selected by the base station selector 80. Although the weights for the base stations other than the reference base station among the base stations 12 are calculated, the present invention is not limited to this mode, that is, the jitter of the base stations 12 selected by the base station selection unit 80 is reduced. The standard deviation of the quantity is the highest It is also possible to base stations other than the small base station and the reference base station.

  The above description is only an embodiment, and the present invention can be implemented in variously modified and improved forms based on the knowledge of those skilled in the art.

It is a figure explaining an example of a structure of the mobile station positioning system of this invention. It is a figure explaining an example of a structure and function of a mobile station in the mobile station positioning system of FIG. It is a figure explaining an example of a structure of the base station in the mobile station positioning system of FIG. It is a figure explaining the outline | summary of the function which the electronic control apparatus of the base station of FIG. 3 has. It is a figure explaining the relationship of each parameter | index in calculation of the position of a mobile station. It is a figure explaining an example of the information memorize | stored in the relationship memory | storage part of the base station of FIG. It is a figure explaining an example of a structure of the positioning server in the mobile station positioning system of FIG. It is a figure explaining the outline | summary of the function which the electronic control apparatus of the positioning server of FIG. 7 has. It is a figure explaining the principle of the positioning by the TDOA positioning part of the positioning server of FIG. It is a figure explaining the positioning of the weight matrix in the mobile station positioning system of FIG. 3 is a flowchart for explaining an example of a control operation in calculating the position of a mobile station in the mobile station positioning system of FIG. 1. It is a figure explaining the function which the electronic control apparatus of the base station which comprises the mobile station positioning system in another Example of this invention has, Comprising: It is a figure corresponding to FIG. It is a figure explaining the function which the electronic control apparatus of the positioning server which comprises the mobile station positioning system in another Example of this invention has, Comprising: It is a figure corresponding to FIG. It is a figure explaining the structure of the mobile station positioning system in another Example of this invention. It is a figure explaining the function which the electronic control apparatus of the positioning server which comprises the mobile station positioning system in another Example of this invention has, Comprising: It is a figure corresponding to FIG. It is a figure explaining an example of the information memorized by base station information storage part 177 of Drawing 15. It is a flowchart explaining an example of the operation | movement in selection of the selection control base station and selection base station by the base station setting part of FIG. It is a figure explaining the function which the electronic control apparatus of the base station which comprises the mobile station positioning system in another Example of this invention has, Comprising: It is a figure corresponding to FIG. It is a figure explaining an example of the information memorized by the receiving intensity distance relation storage part of Drawing 18. It is a figure explaining the function which the electronic control apparatus of the positioning server which comprises the mobile station positioning system in another Example of this invention has, Comprising: It is a figure corresponding to FIG. FIG. 12 is a flowchart for explaining an example of a control operation in the calculation of the position of the mobile station in the mobile station positioning system according to another embodiment of the present invention, corresponding to FIG. 11.

Explanation of symbols

6: Mobile station positioning system 10: Mobile station 12: Base station 14: Positioning server 64: Correlation value calculation unit (correlation calculation unit)
68: Correlation value error conversion unit 70: Peak time detection unit (reception time detection unit)
72: Weight matrix generation unit 74: TDOA positioning unit (positioning unit)
80, 180: Base station selection unit 171: Reception strength detection unit 174: RSSI positioning unit (positioning unit)
187: Control base station selection unit

Claims (7)

Radio waves including spreading codes transmitted from a mobile station are received by a plurality of base stations, and reception results of the radio waves received at the plurality of base stations by a positioning server connected to the plurality of base stations so as to be able to perform data communication A mobile station positioning system for calculating the position of the mobile station based on
A replica code that is included in the radio waves received by the plurality of base stations and has a predetermined amplitude after reception, and a replica code that is a pre-stored spread code that is the same as the spread code included in the radio waves transmitted by the mobile station A correlation calculation unit that calculates the magnitude of the normalized correlation value with the predetermined relationship;
The magnitude of the normalized correlation value calculated by the correlation calculation unit based on a prestored relationship between the magnitude of the normalized correlation value and a communication error in wireless communication between the mobile station and each of the plurality of base stations. A correlation value error converter that calculates an error-related value related to a communication error in wireless communication from the mobile station to each of the plurality of base stations for each of the plurality of base stations;
Based on the error related value in the wireless communication from the mobile station to each of the plurality of base stations, calculated by the correlation value error conversion unit, the positioning of each of the plurality of base stations by a prestored relationship A weight matrix generation unit for determining a weight matrix representing the weight in
Stored in advance using reception results at each of the plurality of base stations when the plurality of base stations receive radio waves transmitted from the mobile station and the weight matrix generated by the weight matrix generation unit. And a positioning unit for calculating the position of the mobile station according to the relationship. The plurality of base stations include a plurality of control base stations capable of performing wireless communication with the mobile station in order to control operation of the mobile station,
A control base station selection unit that selects, from among the plurality of control base stations, a control base station that establishes wireless communication with the mobile station as a selection control base station that controls the operation of the mobile station;
Based on information on a combination of base stations to be selected base stations that are base stations used for positioning of the mobile station when each of the plurality of control base stations stored in advance is the selected control base station A base station selection unit that selects a combination of the selected base stations for the selected control base station selected by the control base station selection unit,
The correlation calculation unit includes a standardized correlation value between a spread code included in a radio wave received by the selected base station selected by the base station selection unit and having a predetermined amplitude after reception, and the replica code Is calculated based on a pre-stored relationship,
The correlation value error conversion unit is calculated by the correlation calculation unit based on a prestored relationship between the magnitude of the normalized correlation value and a communication error in wireless communication between each of the mobile station and the selected base station. Based on the magnitude of the normalized correlation value, an error-related value related to a communication error in wireless communication from the mobile station to each of the selected base stations is calculated for each of the selected base stations,
The weight matrix generation unit is configured to calculate the selected base according to a relationship stored in advance based on the error-related value in wireless communication from the mobile station to each of the selected base stations, calculated by the correlation value error conversion unit. Determine a weight matrix representing the weight at each station's positioning,
The positioning unit uses a reception result at each of the selected base stations when the selected base station receives a radio wave transmitted from the mobile station, and a weight matrix generated by the weight matrix generation unit. The mobile station positioning system according to claim 1, wherein the position of the mobile station is calculated based on a previously stored relationship. A base station selection unit that selects, from among the plurality of base stations, all the base stations that have received radio waves from the mobile station that are targeted for positioning, as selected base stations used for positioning of the mobile station. ,
The correlation calculation unit includes a standardized correlation value between a spread code included in a radio wave received by the selected base station selected by the base station selection unit and having a predetermined amplitude after reception, and the replica code Is calculated based on a pre-stored relationship,
The correlation value error conversion unit is configured so that the correlation calculation unit calculates a correlation between a magnitude of the normalized correlation value and a communication error in a wireless communication of spread codes between the mobile station and each of the selected base stations. Based on the calculated magnitude of the normalized correlation value, an error-related value related to a communication error in wireless communication from the mobile station to each of the selected base stations is calculated for each of the selected base stations,
The weight matrix generation unit is configured to calculate the selected base according to a relationship stored in advance based on the error-related value in wireless communication from the mobile station to each of the selected base stations, calculated by the correlation value error conversion unit. Determine a weight matrix representing the weight at each station's positioning,
The positioning unit uses a reception result at each of the selected base stations when the selected base station receives a radio wave transmitted from the mobile station, and a weight matrix generated by the weight matrix generation unit. The mobile station positioning system according to claim 1, wherein the position of the mobile station is calculated based on a previously stored relationship. The base station has a reception time detection unit that detects a reception time of a radio wave based on a time when a peak of a normalized correlation value calculated by the correlation calculation unit occurs.
The positioning unit calculates the position of the mobile station based on the reception time detected by the reception time detection unit of each of the plurality of selected base stations. The mobile station positioning system according to 1. The base station has a reception intensity detection unit that detects reception intensity when a radio wave transmitted from a mobile station is received,
The positioning unit calculates the position of the mobile station based on the reception strength detected by the reception strength detection unit of each of the plurality of base stations used for positioning of the mobile station. The mobile station positioning system according to any one of claims 1 to 3. The mobile station positioning system according to any one of claims 1 to 5, wherein the base station includes the correlation value error conversion unit. The mobile station positioning system according to any one of claims 1 to 5, wherein the positioning server includes the correlation value error conversion unit.

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