WO2006031004A1

WO2006031004A1 - System and method for determining position of mobile terminal

Info

Publication number: WO2006031004A1
Application number: PCT/KR2005/000319
Authority: WO
Inventors: Tae-Il Kim; Sung-Il Kang; Tae-Kyoung Kwon; Sung-Hee Kim; Won-Seok Lee
Original assignee: Radiant Technologies, Inc.
Priority date: 2004-09-17
Filing date: 2005-02-03
Publication date: 2006-03-23
Also published as: KR100536187B1; US20090017837A1; KR20060041888A

Abstract

A method for determining a position of a mobile terminal in a mobile network including a plurality of base stations (BSs) and repeaters (REs) is provided. In the method, a plurality of BS signal data is received, and the BS signal data includes propagation delay time data and is transmitted from the BSs to the mobile terminal. The BSs or the REs corresponding to the respective BS signal data is determined on the basis of the propagation delay time data. Vector data related to the BSs or REs is generated on the basis of geographic data corresponding to the determined BSs and REs. Position data of the mobile terminal is generated according to the generated vector data. In the step of generating the vector data, a progression order of vectors related to the BSs and the REs is determined according to the BS signal data. The vectors are sequentially determined according to the determined vector progression order. The vectors starts at a BS or a RE currently communicating with the mobile terminal. The present invention makes it possible to utilize the existing BS signal data as they are, to determine a position of a mobile terminal more accurately, and to continuously provide accurate position data regardless of a change in a mobile network.

Description

SYSTEM AND METHOD FOR DETERMINING POSITION OF

MOBILE TE

Technical Field

[1] The present invention relates to a system and method for determining a position of a mobile terminal in a mobile network, and more particularly, to a system and method for determining a position of a mobile terminal, which determines a plurality of vectors on the basis of BS signal data and geographic data on base stations, determines a position of the mobile terminal on the basis of grids into which a mobile network coverage area is divided, compares and analyzes the two determination, and finally determines the position of the mobile terminal. Background Art

[2] Cell ID, Enhanced Cell ID (Ex₅CIT A+RXLEV) are positioning methods based on a radius of a cell. However, such methods induce an excessive error in position data of a mobile terminal in an area having a large cell radius, such as a shadow area and the outer suburbs of a city. Also, the above positioning methods have a drawback in that they cannot maintain an initial accuracy in determination because the Rx signal strength for BS signal data received from a BS is variable. Disclosure of Invention Technical Problem

[3] Accordingly, the present invention is directed to a system and method for de¬ termining a position of a mobile terminal, which substantially obviates one or more of the problems due to limitations and disadvantages of the related art.

[4] An object of the present invention is to provide a positioning method for a mobile terminal, which utilizes the existing BS signal data as they are because it generates vectors on the basis of BS signal data received from BSs and determines position data for the mobile terminal.

[5] Another object of the present invention is to provide a positioning method for a mobile terminal, which make it possible to determine a position of the mobile terminal more accurately by determining whether or not the BS signal data is received via a repeater.

[6] A further object of the present invention is to provide a positioning method for a mobile terminal, which makes it possible to provide more accurate and reliable position data for a motile terminal with reference to position data according to the existing positioning method.

[7] A still further object of the present invention is to provide a positioning method for a mobile terminal, which makes it possible to continuously provide accurate position data for the mobile terminal regardless of a change in a mobile network. Technical Solution

[8] To achieve these and other advantages and in accordance with the purpose of the present invention, as embodied and broadly described, there is provided a method for determining a position of a mobile terminal in a mobile network including a plurality of base stations (BSs). The method comprises the steps of: receiving a plurality of BS signal data, the BS signal data including BS ID data and being transmitted from the BSs to the mobile terminal; determining the BSs corresponding to the respective BS signal data on the basis of the BS ID data; generating vector data related to the BSs on the basis of geographic data corresponding to the determined BSs; and generating position data of the mobile terminal according to the generated vector data, wherein the step of generating the vector data comprises the steps of: determining a progression order of vectors related to the BSs according to the BS signal data; and sequentially de¬ termining the vectors according to the determined vector progression order, the vectors starting at a BS currently communicating with the mobile terminal.

Advantageous Effects

[9] The inventive positioning system and method enables a mobile terminal to determine its position on the basis of BS signal data received from BSs, thereby making it possible to determine a position of the mobile terminal without installing an additional hardware device in the mobile terminal or a mobile network.

[10] The inventive positioning method can be applied to not only a synchronous network but also an asynchronous network, and also to a mobile network including repeaters.

[11] The inventive positioning system and method makes it possible to determine more accurate final position data by comparing position data obtained by the existing po¬ sitioning method with position data obtained by the inventive vector-based positioning method.

[12] The inventive positioning system and method makes it possible to continuously provide more accurate position data by updating a change in a mobile network.

[13] The inventive method makes it possible to prevent a cost required for constructing a separate platform and a system load by installing the inventive positioning system in a mobile terminal. Brief Description of the Drawings

[14] FIG. 1 is a schematic diagram illustrating an exemplary network structure including a conventional mobile network and a positioning system according to the present invention. [15] FIG. 2 is a flow diagram illustrating a positioning method according to a preferred embodiment of the present invention.

[16] FIG. 3 is a diagram illustrating a database structure including geographic data on

BSs according to the present invention.

[17] FIGs. 4 through 6 are diagrams illustrating a method for determining a position of a mobile terminal in a synchronous mobile network by using a vector according to the present invention.

[18] FIGs. 7 through 9 are diagrams illustrating a method for determining a position of a mobile terminal in an asynchronous mobile network by generating vector data, according to the present invention.

[19] fig. 10 is a flow diagram illustrating a method for determining position data based on a self learning method according to the present invention.

[20] fig. 11 is a diagram illustrating an example of second position data on plural grids into which a mobile network coverage area is divided, according to the present invention.

[21] fig. 12 is a diagram illustrating an example of a second database according to the present invention.

[22] fig. 13 is a flow diagram illustrating processes performed in a weighted average method according to the present invention.

[23] fig. 14 is a block diagram of a positioning system according to a preferred embodiment of the present invention.

[24] fig. 15 is a block diagram of a general computer usable for performing the po¬ sitioning method for a mobile terminal according to the present invention. Best Mode for Carrying Out the Invention

[25] Hereinafter, preferred embodiments of the present invention will be described in detail with reference to accompanying drawings.

[26] FIG. 1 is a schematic diagram illustrating an exemplary network structure including a conventional mobile network and a positioning system according to the present invention.

[27] Referring to FIG. 1, a mobile network includes plural BSs (BSs), and a mobile terminal receives BS signal data from the plural BSs. 'The plural BSs' include a reference (or main) BS currently communicating with the mobile terminal and sub-BSs neighboring the reference BS. Accordingly, the mobile terminal continuously receives BS signal data not only from the reference BS in a reference cell where the mobile terminal is currently located, but also from BSs in sub-cells neighboring the reference cell. The mobile terminal transmits the received BS signal data to the inventive po¬ sitioning system, and the positioning system determines a position of the mobile terminal by using a vector method based on a database containing geographic data on the respective BSs. In the present invention, 'the reception of BS signal data from a mobile terminal' includes not only a case where the positioning system receives BS signal data directly from the mobile terminal, but also a case where BS signal data received from the mobile terminal is stored in a specific system (or place) of the mobile network and the positioning system accesses the specific system to thereby obtain the BS signal data.

[28] Also, the positioning system stores second position data obtained from the existing positioning method in a second database, and generates final position data on the basis of the second position data, thereby making it possible to generate position data on the mobile terminal more accurately and reliably.

[29] FIG. 2 is a flow diagram illustrating a positioning method according to a preferred embodiment of the present invention.

[30] Referring to FIG. 2, a mobile terminal receives BS signal data from plural BSs. A mobile network according to the present invention may be a synchronous mobile network or an asynchronous mobile network. In case of a synchronous mobile network, each BS signal data may include a PN (pseudo noise) offset, a PN delay time and a received (Rx) signal strength. The PN offset includes data for identifying from which BS a received BS signal is transmitted. The PN delay time is a propagation delay time until the arrival of a BS signal at the mobile terminal. The received signal strength is the strength of a BS signal received at the mobile terminal. In Step S201, the mobile terminal receives BS signal data whereby the positioning system can use the BS signal data received at the mobile terminal

[31] In case of an asynchronous mobile network, each BS signal data may include BS

ID (identification) data (or cell ID data), a round- trip delay time and an Rx signal strength, the functions of which correspond respectively to those of the above-stated synchronous BS signal data.

[32] In Step S202, the positioning system determines a BS corresponding to each BS signal data on the basis of the received BS signal data. For example, the positioning system may identify and determine a BS on the basis of the PN offset contained in the BS signal data. The Step S202 for determining a BS will be described in detail later.

[33] In Step S203, the positioning system searches geographic data on BSs from a database and extracts geographic data corresponding to the determined BS. In an embodiment of the present invention, geographic data on BSs is stored and maintained in a database, and the positioning system can obtain the geographic data by searching the database.

[34] FIG. 3 is a diagram illustrating a database structure including geographic data on

BSs according to the present invention. [35] Referring to FIG. 3, a database according to an embodiment of the present invention includes BS ID data for identifying BSs and corresponding geographic data on the BSs. For example, latitude and longitude may be used as the geographic data. As shown in FIG. 3, geographic data on BS 1 is latitude 37.235 and longitude 127.314.

[36] Referring back to FIG. 2, in Steps S204 and S205, vector data used for performing the positioning method is generated on the basis of the geographic data extracted in Step S203.

[37] In Step S204, the positioning system determines a progression order of vectors related to the plural BSs on the basis of BS signal data. For example, the positioning system may determine a BS causing the shortest propagation delay time as a first priority BS in consideration of the propagation delay time data contained in the BS signal data. Also, the positioning system may determine a BS inducing the strongest Rx signal strength as a first priority BS in consideration of the Rx signal strength data contained in the BS signal data. A first vector is a virtual path from a first priority BS to a second priority BS, and the vectors related to the plural BSs can be continuously determined according to the previously-determined vector progression order. In a preferred embodiment of the present invention, the vector starts at the reference BS currently communicating with the mobile station.

[38] In Step S205, the positioning system determines the sizes of the vectors whose progression order is determined in Step S204. For example, the size of the first vector may be determined as a value obtained by multiplying the length of a vector connecting the first and second priority BSs by a first given value. The length of the vector is a distance between the first and second priority BSs, which can be calculated from geographic data (latitude, longitude) on the two BSs. In an embodiment of the present invention, the first given value is experimentally determined as 0.20. That is, the size of the first vector is determined as a value obtained by multiplying the length of a vector connecting the first and second priority BSs by 0.20, whereby the first vector is finally determined.

[39] A second vector starts at the end point of the first vector and is then directed to a third priority BS. The size of the second vector is determined as a value obtained by multiplying a distance between the second and third priority BSs by a second given value. Accordingly, the second vector is finally determined. In an embodiment of the present invention, the second given value is experimentally determined as 0.15.

[40] A third vector starts at the end point of the second vector and is then directed to a fourth priority BS. The size of the third vector is determined as a value obtained by multiplying a distance between the third and fourth priority BSs by a third given value. Accordingly, the third vector is finally determined. In an embodiment of the present invention, the third given value is experimentally determined as 0.1. [41] In Step S206, the positioning system obtains position data on the mobile terminal on the basis of the determined progression order and sizes of the vectors. In the inventive positioning method, the end point of the third vector is the position of the mobile terminal. That is, geographic data on the end point of the third vector corresponds to the position data on the mobile terminal. In further embodiments of the present invention, a fourth vector, a fifth vector and so on can be sequentially determined on the basis of BS signal data received from the remaining BSs, and the position of the mobile terminal can be determined as the end point of the last vector.

[42] In another embodiment of the present invention, a mobile network may further include a plurality of repeaters (REs) as well as a plurality of BSs as shown in FIG. 1. The repeater amplifies a weak BS signal transmitted from a BS to the mobile terminal so as to provide a user with a more excellent communication service. The repeater improves a call quality in a shadow area (where a BS signal cannot arrive) and in a building's interior and an underground (where a propagation environment is poor), and enhances a system coverage. The repeater is widely used by mobile communication service providers due to its low installation, maintenance and site securement costs, that is, its low investment cost.

[43] If the mobile network includes repeaters, a BS signal received at the mobile terminal may be a signal transmitted directly from a BS, or may be a signal transmitted via at least one or more repeaters. If the received BS signal is a signal transmitted via at least one or more repeaters, the vectors for the inventive positioning method must be determined on the basis of the repeaters, not the BS. Accordingly, the inventive po¬ sitioning system must be able to discern whether the received BS signal is transmitted via a repeater or directly from a BS.

[44] For an example, the inventive positioning system can performing the above discernment operation by using a propagation delay time contained in BS signal data. That is, the discernment operation is performed on the basis of a PN delay time in case of a synchronous mobile network, and a round-trip delay time in case of an asynchronous mobile network. In case of an asynchronous mobile network, a TA (timing advance) value in the 2G (second generation) mobile network and an RTT (round-trip time) in the 3G (third generation) mobile network can be used as the above round-trip delay time.

[45] The inventive positioning method illustrated in FIG. 2 will now be described dis- criminately according to synchronous and asynchronous mobile networks.

[46] FIGs. 4 through 6 are diagrams illustrating a method for determining a position of a mobile terminal in a synchronous mobile network by using a vector according to the present invention.

[47] Referring to fig. 4, a mobile terminal receives respective BS signal data from a reference BS (BSO) and sub-BSs (BSl, BS2 and BS3). The received BS signal data are transmitted to the inventive positioning system, and the positioning system sorts the BS signal data on the basis of propagation delay time data. As shown in fig. 5, starting with the BS signal data of the BSO having a PN offset of 408, the remaining BS signal data may be sorted in ascending order of a propagation delay time on the basis of a PN delay time.

[48] Thereafter, the positioning system determines whether the BS signal data received at the mobile terminal has been received via a repeater or directly from a base station. Referring to fig. 4, it is assumed that the mobile terminal receives BS signal data re¬ spectively from BSO, BSl, BS2 and BS3, repeaters REO, REl and RE2 are connected to BSO, a repeater RE3 is connected to BSl, and a repeater RE4 is connected to BS2.

[49] The positioning system performs the above determination operation on the basis of a propagation delay time (PN delay time) difference between a currently-analyzed BS signal and the earliest received BS signal (a BS signal having the shortest propagation delay time). If the absolute value of the propagation delay time difference is equal to or greater than a given value (an experimental value: 6 through 8 chips), the currently- analyzed BS signal is determined to be a signal received via a repeater. Otherwise, if the absolute value is smaller than the given value, the currently-analyzed BS signal is determined to be a signal received directly from a BS.

[50] Referring to FIGs. 4 and 5, a BS signal of Rx data order 6 can be determined to be a signal received from BSO because its PN offset is 72. Also, the BS signal of Rx data order 6 can be determined to be a signal received via a repeater because its propagation delay time difference is calculated as -17.3 chip (= -14.3 chip (PN offset: 364) - 3.0 chip (PN offset: 72)).

[51] If a currently-analyzed BS signal is determined to be a signal received via a repeater, the positioning system determines via which of repeaters connected to the BSs the currently-analyzed BS signal has been received. This determination can be made by determining the position of a repeater connected to a BS nearest to the position of a BS corresponding to the earliest received BS signal. Referring to fig. 4, for example, a currently-analyzed BS signal is determined to be received via RE2 nearest to BS3 corresponding to the earliest received BS signal.

[52] The positioning system can determine a BS corresponding to each BS signal or via which of repeaters the BS signal is received by applying the foregoing method to all the BS signals shown in fig. 5.

[53] If a BS or an RE corresponding to each BS signal has been determined, vector data can be sequentially determined based on the geographic data of the determined BS or RE. However, vector data on some BSs or REs are not generated in consideration of Rx signal strength data contained in BS signal data. For example, a BS signal whose strength is lower than a specific level can be excluded from consideration. The specific level can be experimentally determined in consideration of an environment (geographic feature) of a corresponding area. When the specific level is set to 15 in a preferred embodiment of the present invention, the final BS signal data list necessary for generating vector data can be obtained as shown in fig. 6.

[54] A method for generating the vector data will now be described with reference to

FIGs. 4 and 6.

[55] Referring to FIGs. 4 and 6, a first vector starts at the BSO (reference BS) and is then directed to the BSl of Rx data order 3, from which BS signal data is first received. Accordingly, the direction of the first vector is determined. The size of the first vector is determined as a value obtained by multiplying a distance between the BSO and the BSl by a first given (or experimental) value of 0.20. Here, the distance is calculated by using geographic data (latitude and longitude).

[56] A second vector starts at the end point 'A' of the first vector and is then directed to the BS2 of Rx data order 5, whereby the direction of the second vector is determined. The size of the second vector is determined as a value obtained by multiplying a distance between the BSl and the BS2 by a second given (or experimental) value of 0.15.

[57] A third vector starts at the end point 'B' of the second vector and is then directed to the RE2 of Rx data order 6, whereby the direction of the third vector is determined. The size of the third vector is determined as a value obtained by multiplying a distance between the BS2 and the RE2 by a third given (or experimental) value of 0.10.

[58] As above, the first, second and third vectors are sequentially determined, whereby position data on the mobile terminal can be generated based on a point corresponding to the end point of the third vector (or a point obtained by multiplying the end point of the third vector by a given value). As described previously, it is preferable that the given values for determining the sizes of the respective vectors are gradually reduced ("0.20 ->0.15 ->0.10") in accordance with the progression order of the respective vectors.

[59] FIGs. 7 through 9 are diagrams illustrating a method for determining a position of a mobile terminal in an asynchronous mobile network by generating vector data, according to the present invention.

[60] Referring to fig. 7, a mobile terminal receives respective BS signal data from a reference BS (BSO) and sub-BSs (BSl, BS2 and BS3). The received BS signal data are transmitted to the inventive positioning system, and the positioning system sorts the plural BS signal data on the basis of an Rx signal strength. As shown in fig. 8, starting with the BS signal data of the BSO having a Cell ID of '3711', the remaining BS signal data may be sorted in descending order of the Rx signal strength. In another embodiment of the present invention, the BS signal data order (or Rx data order) may be determined on the basis of a round-trip delay time (TA).

[61] Thereafter, the positioning system determines whether the BS signal data received at the mobile terminal has been received via a repeater or directly from a base station. Referring to fig. 7, it is assumed that the mobile terminal receives BS signal data re¬ spectively from BSO, BSl, BS2 and BS3, and repeaters REO and REl are connected to BSO.

[62] The positioning system performs the above determination operation on the basis of a round-trip time contained in a BSO signal received at the mobile terminal. If the round-trip time is equal to or greater than a specific value (an experimental value: 5 through 7 chip), the received BSO signal is determined to be a signal received via a repeater. Otherwise, if the round-trip time is smaller than the specific value, the received BSO signal is determined to be a signal received directly from a BS. Referring to fig. 7, a BS signal of Rx data order 1 can be determined to be a signal received via a repeater connected to the BSO because its round-trip time is 9 chip.

[63] If a received BS signal is determined to be a signal received via a repeater, the po¬ sitioning system determines via which of repeaters connected to the BSs signal has been received. This determination can be made by determining the position of a repeater connected to a parent BS nearest to a BS causing an Rx signal strength next higher than the BSO's Rx signal strength. Referring to fig. 7, a BS signal of Rx data order 1 is determined to be received via the REl connected to the parent BSO nearest to the BSl causing the highest Rx signal strength.

[64] The positioning system can determine a BS corresponding to each BS signal or via which of repeaters the BS signal is received by applying the foregoing method to all the BS signals shown in fig. 8.

[65] If a BS or an RE corresponding to each BS signal has been determined, vector data can be sequentially determined based on the geographic data of the determined BS or RE. However, vector data on some BSs or REs are not generated in consideration of Rx signal strength data contained in BS signal data. For example, a BS or RE signal whose strength is lower than a specific level can be excluded from consideration. The specific level is set to '10' in a preferred embodiment of the present invention. Ac¬ cordingly, the final BS signal data list necessary for generating vector data can be obtained as shown in fig. 9.

[66] A method for generating the vector data will now be described with reference to

FIGs. 7 and 9.

[67] Referring to FIGs. 7 and 9, a first vector starts at the REl not the BSO (reference

BS) and is then directed to the BSl of Rx data order 2, from which BS signal data is first received. Accordingly, the direction of the first vector is determined. The size of the first vector is determined as a value obtained by multiplying a distance between the REl and the BSl by a first given (or experimental) value of 0.20. Here, the distance is calculated by using geographic data (latitude and longitude).

[68] A second vector starts at the end point 'A' of the first vector and is then directed to the BS2 of Rx data order 3, whereby the direction of the second vector is determined. The size of the second vector is determined as a value obtained by multiplying a distance between the BSl and the BS2 by a second given (or experimental) value of 0.15.

[69] A third vector starts at the end point 'B' of the second vector and is then directed to the BS3 of Rx data order 4, whereby the direction of the third vector is determined. The size of the third vector is determined as a value obtained by multiplying a distance between the BS2 and the BS3 by a third given (or experimental) value of 0.10.

[70] As above, the first, second and third vectors are sequentially determined, whereby position data on the mobile terminal can be generated based on a point corresponding to the end point of the third vector (or a point obtained by multiplying the end point of the third vector by a given value). As described previously, it is preferable that the given values for determining the sizes of the respective vectors are gradually reduced ('0.20 ->0.15 -> 0.10') in accordance with the progression order of the vectors.

[71] Although position data on the mobile terminal has been determined from the end point of the third vector in FIGs. 7 through 9, the mobile terminal position data can also be determined from the end point of a fourth vector, a fifth vector or so on by applying the above-stated method in order of the fourth vector, the fifth vector and so on according to the number of the BS signal data received at the mobile terminal.

[72] The method for determining the position of a mobile terminal by generating vector data on the basis of BS signal data has been described up to now. When different position data values can be obtained through the conventional positioning method, a self learning methodology (SLM) for enabling the inventive positioning system to determine more accurate position data by using the different position data values will now be described.

[73] fig. 10 is a flow diagram illustrating a method for determining position data based on a self learning methodology according to the present invention.

[74] Referring to fig. 10, second position data are determined in Step S601. The second position data correspond to position data on plural grids into which a mobile network coverage area is divided. That is, the second position data is determined by a second positioning method, not by the foregoing vector-based method shown in FIG. 2. The second positioning method may be various conventional positioning methods, such as a positioning method using a GPS receiver.

[75] fig. 11 is a diagram illustrating an example of second position data on plural grids into which a mobile network coverage area is divided, according to the present invention. Referring to fig. 11, the grid is a unit obtained by dividing two-dimensional geographic data (latitude, longitude) by a reference length. The reference length may be several ten meters through several hundred meters. The second position data are representative values or specific values in the grids, and may be properly determined according to the respective grids.

[76] In Step S602, second BS signal data on the respective grids are determined from the second position data determined by the second positioning method, and the determined second BS signal data are stored and maintained in a second database.

[77] fig. 12 is a diagram illustrating an example of a second database according to the present invention. Referring to fig. 12, at least one or more second BS signal data may be stored per second position data. The second BS signal data may be selected out of BS signal data received from some BSs (for example, BSs causing higher Rx signal strengths) or received via a repeater, or may be only a propagation delay time and an Rx signal strength. In fig. 12, second BS signal data received from four BSs are stored for a grid having second position data of '(a, a)'.

[78] In Step S603, the inventive positioning system compares the BS signal data used in the foregoing vector-based method with the second BS signal data, and searches second position data corresponding to the BS signal data from the second database. That is, the positioning system searches the position of a grid, which has data most similar to the BS signal data received at the mobile terminal, from the second database by using a pattern matching technique, to thereby obtain second position data.

[79] In Step S604, the positioning system generates the final position data on the basis of the obtained second position data and the vector-based position data. For example, the final position data may be the average of the second position data and the vector- based position data, or may be a value obtained by adding weighted second position data and weighted vector-based position data.

[80] In an embodiment of the present invention, the inventive positioning system may not directly perform the Steps S601 and S602. That is, when the second database storing the second BS signal data has been already constructed, the inventive po¬ sitioning system may perform only the Steps S603 and S604 by searching for and referring to the constructed second database.

[81] Accordingly, the present invention makes it possible to more accurately determine the position of a mobile terminal by combining the vector-based positioning method shown in FIG. 2 and the grid-based positioning method shown in FIGs. 10 through 12.

[82] The grid-based positioning method has, however, a drawback in that it cannot rapidly cope with a change in a mobile network. For example, when a new BS or repeater is added to the mobile network, or when the configuration and the wave propagation direction of a corresponding BS are changed, BS signal data cor¬ responding to neighboring grids are also changed. In order to continuously provide accurate position data by spontaneously updating such a change in the mobile network, the inventive positioning system gradually reflects a change of signal data in a grid by using a weighted average method.

[83] fig. 13 is a flow diagram illustrating processes performed in a weighted average method according to the present invention.

[84] Referring to fig. 13, in Step S701, the inventive positioning system determines third position data by using a second mobile terminal. That is, the third position data is obtained by using another mobile terminal (a second mobile terminal equipped with a GPS receiver) other than the vector-based mobile terminal.

[85] In Step S702, the second mobile terminal receives signal data related to the third position data for a corresponding BS, that is, third BS signal data.

[86] In Step S703, the second BS signal data stored in the second database is updated on the basis of the third BS signal data by associating the second BS signal data with the second position data corresponding to the third position data. At this time, the updated and newly-stored second BS signal data 'a" is obtained by multiplying the second BS signal data 'a' and the third BS signal data 'b' respectively by weights 'w' and '(1-w)' and adding the two multiplication results. That is, the newly-stored second BS signal data 'a" can be expressed by Equation 1 below.

[87] a' = wxa + (l-w)xb (Eq.l)

[88] As described above, the inventive positioning system and method continuously updates BS signal data changed according to a change in a mobile network in a database, thereby making it possible to improve accuracy in the position determination for a mobile terminal through the grid-based SLM.

[89] fig. 14 is a block diagram of a positioning system according to a preferred embodiment of the present invention.

[90] Referring to fig. 14, an inventive positioning system 800 includes a data collector

801, a signal analyzer 802, a vector generator 803, a first database 804 and a first position determiner 805.

[91] The data collector 801 receives plural BS signal data from a mobile terminal. The

BS signal data means data that a mobile terminal receives from a BS, and includes a propagation delay time.

[92] The signal analyzer 802 determines a BS or a repeater corresponding to each BS signal data on the basis of the propagation delay time. Also, the signal analyzer 802 can determine whether or not a BS signal is received via a repeater, by comparing propagation delay time differences between BS signals.

[93] The vector generator 803 generates vector data on the basis of geographic data cor- responding to the determined BS or repeater. For generating the vector data, the vector generator 803 determines the order of vectors related to plural BSs according to BS signal data, and sequentially determines the vectors according to the determined order. Here, an initial vector out of the vectors starts at a BS or a repeater that currently com¬ municates with the mobile terminal.

[94] In an embodiment of the present invention, the positioning system 800 may further include the first database 804. The first database 804 stores geographic data on plural BSs and repeaters, and the vector generator 803 may obtain geographic data on a BS or a repeater from the first database 804.

[95] The first position determiner 805 determines position data on the mobile terminal on the basis of the vector data generated from the vector generator 803.

[96] The positioning system 800 may further include a second database 806 and a second position determiner 807.

[97] The second database 806 divides a mobile network coverage area into plural grids, and stores second BS signal data on the grids in association with second position data. The second position data may be determined through a second positioning method.

[98] The second position determiner 807 compares BS signal data and second BS signal data, searches second position data corresponding to the BS signal data from the second database 804, and generates the final position data on the basis of the searched second position data and the position data.

[99] In another embodiment of the present invention, the positioning system 800 may further include a third position determiner 808, a second data collector 809 and a BS signal data updater 810.

[100] The third position determiner 808 determines third position data by using a second mobile terminal equipped with a GPS receiver, and the second data collector 809 receives third BS signal data on the third position data by using the second mobile terminal.

[101] On the basis of the third BS signal data, the BS signal data updater 810 updates the second BS signal data stored in the second data base in association with second position data corresponding to the third position data.

[102] The construction of the inventive positioning system has been described up to now, and the foregoing technical contents of the inventive positioning method can be applied to the construction as they are. The inventive positioning system may be a de¬ termination server installed in a BS, a BS controller or a BS switch, and may be installed wherever it can receive BS signal data. For example, when considering management and investment efficiencies and so on, it is preferable that the positioning system is independently connected to the existing core network (or a subsystem of a network). [103] In another embodiment of the present invention, the positioning system 800 is installed and operated in a mobile terminal in consideration of rapid improvement in resource environments of a mobile terminal, such as a processor, a memory, an RF module and so on. In this case, such a mobile terminal can perform a positioning function without the help of a determination server via a mobile network by using BS signal data received from respective BSs. That is, the positioning system 800 is not constructed in a separate platform, but is built in a mobile terminal. In this case, a system load that may be generated due to messages exchanged between a mobile terminal and a determination server during the position determination operation, and a cost required for constructing the separate platform in the embodiment illustrated in FIGs. 2 and 14 can be prevented, thereby enabling mobile communication service providers to rapidly introduce and activate a location-based service (LBS).

[104] In further another embodiment of the present invention, in consideration of resource restrictions, only some elements of the positioning system 800 are pref¬ erentially installed in a mobile terminal, and the remaining elements of the system 800 are installed in a mobile network in a separate platform type. For example, the data collector 801, the signal analyzer 802, the vector generator 803, the first database 804 and the first position determiner 805 are installed in a mobile terminal in a module type, and the remaining elements are separately installed in a mobile network.

[105] The inventive positioning method may be embodied as computer-readable code on a computer readable medium. The computer-readable medium may include program codes, data files, data structure and so on, separately or associatively. The program code written in the computer-readable medium may be a code specifically designed and constructed for the present invention, or may be codes well-known to those skilled in the computer software art. Examples of the computer-readable medium include magnetic media such as hard disks, floppy disks and magnetic tapes; optical media such as CD-ROMs and DVDs; magneto-optical media such as floptical disks; and hardware devices that are specifically configured to store and execute computer codes, such as ROMs, RAMs and flash memories. The computer-readable medium may also be a transmission medium such as an optical or metallic waveguide including carriers for transmitting signals designating a program code, a data structure and the like. Examples of the program code include a machine language code made by a compiler, and a high level language code executable by a computer with a interpreter. The hardware device may be configured to operate as one or more software modules so as to perform the operation of the present invention, and vice versa.

[106] fig. 15 is a block diagram of a general computer usable for performing the po¬ sitioning method for a mobile terminal according to the present invention.

[107] Referring to FIG. 15, a computer device 900 includes one or more processors 910 connected to a main memory including a RAM 920 and a ROM 930. The processor 910 is also called a CPU. As widely known in the art, The ROM 930 unidirectionally transmits data and instruction to the CPU, and the RAM 920 bidirectionally transmits/ receives data and instruction. The RAM 920 and the ROM 930 may include any computer-readable medium. A mass storage 940 is bidirectionally connected to the processor 910 to thereby provide an additional data storage capacity, and may be any computer-readable medium. The mass storage 940 is generally an auxiliary memory slower than the main memory, and is used for storing a program, data and so on. A specific mass storage such as a CD-ROM 960 may also be used. The processor 910 is connected to one or more I/O interfaces 950 such as a video monitor, a track ball, a mouse, a keyboard, a microphone, a touch screen display, a card reader, a magnetic or paper tape reader, a voice or handwriting recognizer, a joystick, or well-known computer I/O devices. The processor 910 can be connected to the wired/wireless network via a network interface 970. The inventive positioning method can be performed through such a network connection. The foregoing devices are well-known to those skilled in the computer hardware/software art. While the present invention has been described and illustrated herein with reference to the preferred embodiments thereof, it will be apparent to those skilled in the art that various modifications and variations can be made therein without departing from the spirit and scope of the invention. Thus, it is intended that the present invention covers the modifications and variations of this invention that come within the scope of the appended claims and their equivalents.

Claims

[1] A method for determining a position of a mobile terminal in a mobile network including a plurality of base stations (BSs), the method comprising the steps of: receiving a plurality of BS signal data, the BS signal data including BS ID (identification) data and being transmitted from the BSs to the mobile terminal; determining the BSs corresponding to the respective BS signal data on the basis of the BS ID data; generating vector data related to the BSs on the basis of geographic data cor¬ responding to the determined BSs; and generating position data of the mobile terminal according to the generated vector data, wherein the step of generating the vector data comprises the steps of: determining a progression order of vectors related to the BSs according to the BS signal data; and sequentially determining the vectors according to the determined vector progression order, the vectors starting at a BS currently communicating with the mobile terminal.

[2] The method of claim 1, wherein the mobile network is a synchronous network, the BS signal data includes propagation delay time data, and the vector progression order is determined in ascending order of the propagation delay time.

[3] The method of claim 1, wherein the mobile network is an asynchronous network, the BS signal data includes Rx signal strength data, and the vector progression order is determined in descending order of the Rx signal strength.

[4] The method of claim 1, wherein the BS signal data includes Rx signal strength data, and a BS related to BS signal data whose Rx signal strength is lower than a predetermined level is excluded in determining the vector progression order.

[5] The method of claim 1, wherein the step of sequentially determining the vectors comprises the steps of: determining a direction of a first vector so that the first vector stars at a first priority BS and is then directed to a second priority BS; determining a size of the first vector as a value obtained by multiplying a distance between the first priority BS and the second priority BS by a pre¬ determined value; and determining the first vector between the first priority BS and the second priority BS on the basis of the determined direction and size.

[6] The method of claim 5, wherein the predetermined value is gradually decreased according to the vector progression order.

[7] A method for determining a position of a mobile terminal in a mobile network including a plurality of base stations (BSs) and repeaters (REs), the method comprising the steps of: receiving a plurality of BS signal data, the BS signal data including propagation delay time data and being transmitted from the BSs to the mobile terminal; determining the BSs or the REs corresponding to the respective BS signal data on the basis of the propagation delay time data; generating vector data related to the BSs or REs on the basis of geographic data corresponding to the determined BSs and REs; and generating position data of the mobile terminal according to the generated vector data, wherein the step of generating the vector data comprises the steps of: determining a progression order of vectors related to the BSs and the REs according to the BS signal data; and sequentially determining the vectors according to the determined vector progression order, the vectors starting at a BS or a RE currently communicating with the mobile terminal.

[8] The method of claim 7, wherein the mobile network is a synchronous network, the BS signal data includes propagation delay time data, and the vector progression order is determined in ascending order of the propagation delay time.

[9] The method of claim 8, wherein the step of determining the BSs or the REs corresponding to the respective BS signal data comprises the steps of: determining a first propagation delay time that is shortest among the propagation delay time data; determining a time difference between the first propagation delay time and a second propagation delay time; and determining that BS signal data related to the second propagation delay time is received via an RE, if the time difference is equal to or larger than a pre¬ determined value.

[10] The method of claim 9, wherein the step of determining that the BS signal data is received via the RE comprises the step of determining an RE nearest to a BS related to a earliest-received BS signal out of plural BS signals as the RE via which the BS signal data is received, if a BS related to the second propagation delay time is connected to a plurality of REs.

[11] The method of claim 7, wherein the mobile network is an asynchronous network, and the BS signal data includes a round- trip delay time.

[12] The method of claim 11, wherein the step of determining the BSs or the

REs corresponding to the respective BS signal data comprises the step of determining that BS signal data related to the round-trip delay time is received via an RE, if the round-trip delay time is equal to or larger than a given value.

[13] The method of claim 12, wherein the step of determining that the BS signal data is received via the RE comprises the step of determining an RE connected to a BS nearest to a BS causing a next highest Rx signal strength when compared to a BS currently communicates with the mobile terminal as the RE via which the BS signal data is received, if a BS related to the round-trip delay time is connected to a plurality of REs.

[14] The method of claim 1 or 7, further comprising the steps of dividing a coverage area of the mobile network into a plurality of grids, de¬ termining second BS signal data for the grids in association with second position data and then storing and maintaining the determined second BS signal data in a second database, the second position data being determined with regard to the grids by using a second mobile terminal positioning method; comparing the BS signal data with the second BS signal data and then searching the second position data corresponding to the BS signal data from the second database; and generating final position data on the basis of the searched second position data and the vector-based position data.

[15] The method of claim 14, wherein the final position data is determined by averaging the position data and the searched second position data or by adding weighted second position data and weighted vector-based position data.

[16] The method of claim 14, wherein the second mobile terminal positioning method is performed by using a GPS receiver.

[17] The method of claim 14, further comprising the steps of: determining third position data by using a second mobile terminal equipped with a GPS receiver; receiving third BS signal data for the third position data by using thesecond mobile terminal; and updating the second BS signal data stored in the second database on the basis of the third BS signal data.

[18] The method of claim 17, wherein the updated second BS signal data 'a" is determined by an equation below a' = wxa + (l-w)xb, 0<w<l where 'a' is second BS signal data, 'b' is third BS signal data and 'w' is a weight.

[19] A system for determining a position of a mobile terminal in a mobile network including a plurality of base stations (BSs) and repeaters (REs), the system comprising: a data collector for receiving a plurality of BS signal data, the BS signal data being transmitted from the BSs to the mobile terminal; a signal analyzer for determining the BSs or the REs corresponding to the respective BS signal data on the basis of the BS signal data; a vector generator for generating vector data related to the BSs or REs on the basis of geographic data corresponding to the determined BSs and REs; and a position determiner for determining position data of the mobile terminal according to the generated vector data, wherein the vector generator determines a progression order of vectors related to the BSs and the REs according to the BS signal data, and sequentially determines the vectors according to the determined vector progression order, the vectors starting at a BS or a RE currently communicating with the mobile terminal.

[20] The system of claim 19, further comprising: a second database for dividing a coverage area of the mobile network into a plurality of grids and then storing second BS signal data for the grids in as¬ sociation with second position data, the second position data being determined by using a second mobile terminal positioning method; and a second position determiner for comparing the BS signal data with the second BS signal data, searching the second position data corresponding to the BS signal data from the second database, and generating final position data on the basis of the searched second position data and the position data.

[21] The system of claim 20, further comprising: a third position determiner for determining third position data by using a second mobile terminal equipped with a GPS receiver; a second data collector for receiving third BS signal data for the third position data by using the second mobile terminal; and a BS signal data updater for updating the second BS signal data stored in the second database on the basis of the third BS signal data.

[22] The system of claim 19, wherein the system is installed in the mobile terminal.

[23] A computer-readable medium in which a program for executing any one method of claims 1 through 13 and 15 through 18 is written.