JP2002296335A - System of specifying position of mobile terminal - Google Patents

Abstract

PROBLEM TO BE SOLVED: To easily and surely specify the position of a mobile terminal by making the mobile terminal communicate with three base stations. SOLUTION: A range difference Δ12 between a base station 1 and a base station 2, a range difference Δ23 between the base station 2 and a base station 3 and a range difference Δ31 between the base station 3 and the base station 1, with respect to the mobile terminal, are acquired (S1). Then, on the basis of the three range differences, a linear expression of y0 =ωx0 +δ regarding the coordinates (x0 , y0 ) of the mobile terminal is created (S2). In addition, by using the range differences Δ12 , Δ23 , Δ31 , the three equations for hyperbola, regarding the coordinates (x0 , y0 ) is created (S3). The coordinates of respective points of intersection of the linear expression and the three hyperbolas are found (S4). Then, x0 whose value obtained by squaring each of the three points of intersection, the coordinates (x0 , y0 ) and distances ε12 , ε23 , ε31 , to be added which becomes a minimum is found (S5).

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a system for locating a mobile terminal such as a wireless mobile terminal, and more particularly to a system for specifying a position of a mobile terminal capable of communicating with three base stations. Related to the location system.

[0002]

2. Description of the Related Art Conventionally, there has been proposed a technique for specifying a position of a mobile terminal, which can receive information of a base station or transmit information to the base station.

In such a technique, a radio wave emitted from a mobile terminal such as a mobile phone is received by a base station, and the base station transmits the radio wave based on a difference in radio wave intensity and arrival time at each base station. The distance was specified. In addition, such conventional techniques include receiving a radio wave emitted from a base station at a mobile terminal, and determining a distance between the base station and the mobile terminal based on a difference in radio wave intensity and arrival time from each base station. Had been identified. And, the position of the mobile terminal has been specified by specifying the distance between the plurality of base stations and the mobile terminal. Hereinafter, a conventional method for determining the position of a mobile terminal will be described in detail.

[0004] First, as shown in FIG.
And the positions of the three base stations (base station 1 to base station 3) on the xy coordinates are P _s , P ₁ , P ₂ , and P ₃ , respectively, and the respective coordinates are expressed by equations (11) and (12). Is defined. Then, the mobile terminal 10, respectively the distance between the base station 1 to the base station 3, when _{r 1, r 2, r 3} , r 1,
r ₂ and r ₃ are described as in equation (13).

[0005]

(Equation 5)

[0006] As a first prior art, hyperbolic intersection
A procedure for specifying a position by the point method will be described. in this way,
For the mobile terminal 10, based on the distance difference from each base station
Differences in physical quantities such as time differences seen in communications
Difference), the range difference between base station 1 and base station 2
△₁₂, The range difference between base station 2 and base station 3 △_{twenty three}, Base station 3 and
Range difference of base station 1 △₃₁, Respectively, as in equation (14)
Defined in And △ ₁₂, △_{twenty three}Is actually measured
Thus, according to equation (15), the position coordinates of the mobile terminal 10
X₀, Y₀Was required.

[0007]

(Equation 6)

[0008] As a second prior art, referring to FIGS. 7 and 8, an SX method (Spherical Intersection Met) is described.
hod) will be described.

FIG. 7 shows a mobile terminal 10, a base station 1 serving as a reference base station, and a base station 2 provided separately from the reference base station. Further, in this method, the position P ₁ of the reference base station, an arbitrarily determined origin, the position P _s of the mobile terminal 10, the base station i (base stations other than base station 1 such as base station 2 and base station 3). ) With respect to the base station 1 (reference base station), the distance D _{i, 1} between the base station i and the mobile terminal 10.
_i and the square of the distance from the origin to the base station _i are defined as Ki. Here, i is an integer of 2 or more,
Distance D ₁ of the base station 1 and the mobile terminal 10 is specifically defined as K _s.

Based on such a definition, the following equation (1)
6) to (19) can be derived, and equations (20) to (23) can be derived based on these equations.

[0011]

(Equation 7)

Since the measured value of the range difference often includes an error, the equation (23) does not actually hold.
Therefore, the error ε _i is defined as in Expression (24).
Note that ε, δ, d, and S in equation (24) are expressed by equation (25).
When defined as Expression (28), Expression (24) can be described as Expression (29).

[0013]

(Equation 8)

Here, the square error W is defined as in equation (30), and the position of the mobile terminal 10 is estimated from the condition that J is partially differentiated with respect to the position vector to be zero (see equation (31)). For this purpose, the expressions are expanded as in Expressions (32) to (35).

[0015]

(Equation 9)

If R _s is obtained, the position of the mobile terminal 10 can be obtained from equation (35). If the measurement error is not included in R _s , Expression (36) holds by definition.
By substituting equation (35) into equation (36), equation (37) is obtained. However, a, b, and c in Expression (37) are those shown in Expressions (38) to (40), respectively. Then, from equation (37), R _s which is a positive number is calculated by equation (41)
Is required. Then, equation (35) is added to equation (41).
Equation (42) is derived by substituting.

[0017]

(Equation 10)

Equation (42) shows that the base station i and the mobile terminal 10
Is equal to the radius of a circle centered on the base station i. That is, in this method, as shown in FIG. 8, it is assumed that the location of the mobile terminal 10 is the intersection of the above circle and a circle having a radius R _s centered on the reference base station (base station 1). Presumed.

In this method, one mobile terminal 1
In order to specify the position of 0, the mobile terminal 10 needs to communicate with three or more base stations.

Further, as a third prior art, a PX method (Pl) for linearizing position information of the mobile terminal 10 to directly obtain a solution.
ain Intersection Method). A procedure for determining the position of the mobile terminal 10 using this method will be described with reference to FIG.

In this method, first, the position information (formula (11) and formula (1)) of the mobile terminal 10 and the three base stations are obtained.
Equation (43) is introduced using the distances between the three base stations and the mobile terminal 10 (see Equation (13)). Then, equation (44) is obtained by substituting equation (14) into equation (43).

[0022]

[Equation 11]

Then, from Expression (44), Expression (45) and Expression (46) are derived, and from Expression (46), Expression (4) is obtained.
7) is derived.

[0024]

(Equation 12)

Although Σ in equation (47) is essentially zero, it does not become zero when there is a measurement error. Equation (47) means that (x ₀ , y ₀ ) is located on the first-order straight line. In order to display this as a vector, the parameters shown in equations (48) and (49) are introduced, and if ゼ ロ is set to zero, a linear equation shown in equation (50) is derived. In equation (50), (x ₀ , y ₀ ) is
It is described in the form of a vector P _S. Equation (50)
Can be rewritten as equation (51) if y ₀ is zero and e _ijk is defined as equation (52).

According to this method, one linear equation such as equation (50) is obtained based on information from three base stations. Then, if there are two linear equations, the position (P _s ) of the mobile terminal 10 can be specified as the intersection, as schematically shown in FIG. That is, if information from at least four base stations is obtained, three base stations are selected from the four base stations in two ways, and two linear equations of the equation (50) are derived. The location of the mobile terminal 10 can be specified. In FIG. 9, a straight line obtained based on information from the base station 1, the base station 2, and the base station 3 is represented by L (1, 2, 3),
Base station 2 and base station 4 (base stations 4 are base stations 1 to
A straight line obtained based on information from a base station (different from the base station 3) is represented by L (1, 2, 4).

[0027]

(Equation 13)

It should be noted that the linear equation shown in equation (50) is shown in FIG.
As schematically shown in FIG. 10, the equation corresponds to the formula of the major axis of an ellipse having three base stations (base station 1 to base station 3 in FIG. 10) used for deriving the linear equation.

[0029]

Each of the above-described prior arts has the following problems.

In the first prior art, in order to specify the position of the mobile terminal 10, it is necessary to find the solution of the nonlinear equation shown in equation (15). This is a very complicated operation and requires a high calculation cost.

In the second prior art, as described above, the position of the mobile terminal 10 is estimated from the intersection of two circles. However, in this method, the position is estimated with a slight range difference error. There is a problem that a large error is included in the position coordinates of the mobile terminal. Further, in the second conventional technique, the root of equation (41) becomes an imaginary solution depending on the positional relationship between the mobile terminal 10 and each base station and the degree of error included in the range difference, and the two circles intersect at the intersection. However, there is also a problem that the position of the mobile terminal cannot be specified without the mobile terminal.

In the third prior art, when the position of a mobile terminal is specified, it is necessary for the mobile terminal to simultaneously communicate with four base stations. It is difficult to communicate with four base stations. In other words, it is theoretically possible to specify the position of the mobile terminal by the method according to the third conventional technique, but it is practically difficult.

The present invention has been conceived in view of the above circumstances, and an object of the present invention is to easily specify the position of a mobile terminal using information on three mobile stations that can communicate with the mobile terminal. An object of the present invention is to provide a mobile terminal location specifying system.

[0034]

SUMMARY OF THE INVENTION A mobile terminal location system according to the present invention determines the location of a mobile terminal communicating with a first base station, a second base station, and a third base station. A location specifying system for a mobile terminal to be specified, comprising: a center station that communicates with the first base station, the second base station, and the third base station, wherein the center station includes the first station. The distance between the base station and the mobile terminal is a first distance,
When the distance between the second base station and the mobile terminal is a second distance, and the distance between the third base station and the mobile terminal is a third distance, the first to third distances From a physical quantity based on the difference in distance, a primary expression creating means for creating a linear expression for the position of the mobile terminal, and from the physical quantity based on the first to third distance differences, the position of the mobile terminal And a position determining means for determining a position of the mobile terminal from an intersection on the coordinates of the primary expression and the secondary expression. .

According to the present invention, when the position of the mobile terminal is specified, three base stations that the mobile terminal needs to communicate with can be determined based on the results of communication with these three stations. The position of the mobile terminal can be specified using the primary equation created by the above.

[0036] Thereby, the movement can be performed surely and easily.
The location of the terminal can be specified. Also, the mobile terminal of the present invention
In the position locating system described above, the center station has a two-dimensional location.
In the coordinate system (x, y), the coordinates of the mobile terminal are represented by (x, y).
₀, Y₀), The coordinates of the first base station are (x₁,
y₁), The coordinates of the second base station are (x_Two, Y_Two),Previous
The coordinates of the third base station are (x_Three, Y_Three) Means
Between the mobile terminal and the first base station and the movement
Difference in arrival time of information between the terminal and the second base station
Is the range difference △₁₂And the mobile terminal and the second base
Between base stations and between the mobile terminal and the third base station.
Range difference, which is the difference in arrival time of information _{twenty three}And the moving end
Terminal and the third base station, the mobile terminal and the
Range difference, which is the difference in arrival time of information between one base station
△₃₁And means for acquiring the quadratic expression.
The means is as described above.₁₂, △_{twenty three}, △₃₁, X₁, Y₁, X_Two, Y
_Two, X_Three, And y_ThreeFrom the above, two of the above x and y
Formulas (11) to (13), which are the following formulas, are created.

[0037]

[Equation 14]

The primary equation creating means creates equation (14) as the primary equation, and replaces ω in equation (14) with equation (1).
5), and △ ^t ₁₂₃ in equation (15) is defined by equation (1)
The transposed matrix of △ ₁₂₃ defined by 6) is defined, S ₁₂₃ in equation (15) is defined according to equation (17), δ in equation (14) is defined according to equation (18), and equation (18) E _ijk inside
It was defined according to equation (19), f ₁ ² in the formula (19), f
The ₂ ^2, f ₃ ² defined according to equation (20),

[0039]

(Equation 15)

The position determining means calculates the coordinates (x ₀ , y ₀ ) of the mobile terminal as (x, y) satisfying the linear expression and at least one of the expressions (11) to (13). Preferably, the position of the mobile terminal is determined.

Further, the position identification system of the mobile terminal according to the present invention is provided.
In the system, the center station has a two-dimensional coordinate system (x, y).
, The coordinates of the mobile terminal are represented by (x₀, Y₀),Previous
Let the coordinates of the first base station be (x₁, Y₁), The second group
Let the coordinates of the local office be (x_Two, Y_Two), Coordinates of the third base station
To (x_Three, Y_ThreeMeans) and said mobile terminal
Between the first base station, the mobile terminal and the second base station.
Range difference, which is the difference in arrival time of information between local stations
₁₂Between the mobile terminal and the second base station, and
The arrival time of information between the mobile terminal and the third base station
Range difference △ _{twenty three}And the mobile terminal and the third
Between base stations and between the mobile terminal and the first base station
Range difference, which is the difference between the arrival times of the information₃₁And get
Means further comprising:
△₁₂, △_{twenty three}, △₃₁, X₁, Y₁, X_Two, Y _Two, X_Three,
And y_ThreeFrom the expression, which is a quadratic expression for x and y,
(11) to formula (13) are created,

[0042]

(Equation 16)

The primary equation creating means creates equation (14) as the primary equation, and replaces ω in equation (14) with equation (1).
5), and △ ^t ₁₂₃ in equation (15) is defined by equation (1)
The transposed matrix of △ ₁₂₃ defined by 6) is defined, S ₁₂₃ in equation (15) is defined according to equation (17), δ in equation (14) is defined according to equation (18), and equation (18) E _ijk inside
It was defined according to equation (19), f ₁ ² in the formula (19), f
The ₂ ^2, f ₃ ² defined according to equation (20),

[0044]

[Equation 17]

The position determining means calculates the distance between the intersection of the linear equation and the equation (11) and the (x ₀ , y ₀ ) as ε ₁₂ ,
The intersection of the linear equation and the equation (12) and the (x ₀ ,
y ₀₎ the distance between the epsilon _23, wherein if the intersection of the linear expression in the formula (13) the distance between (x _0, y ₀₎ and the epsilon _31,
The position of the mobile terminal is determined by setting (x, y) that minimizes the sum of the squares of the ε ₁₂ , ε ₂₃ , and ε ₃₁ as the coordinates (x ₀ , y ₀ ) of the mobile terminal. Is preferred.

[0046]

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 is a diagram showing a configuration of a communication system according to an embodiment of the present invention. In this system, when specifying the position of the mobile terminal 10, the mobile terminal 10, the base stations 1 to 3 that communicate with the mobile terminal 10, and the center station 90 that communicates with the base stations 1 to 3 are constituent elements. included.

The center station 90 specifies the position of the mobile terminal 10 by communicating with the base stations 1 to 3. FIG. 2 shows a block diagram of the center station 90.

The center station 90 includes a CPU 91 for overall controlling the operation of the center station 90, a hard disk 92 for storing a basic operation program of the CPU 91, and the like.
A RAM 93 serving as a work area of the CPU 91 and an R for storing an operation program and the like in a positioning process described later.
It includes an OM 94, a database 95 storing the position coordinates of each base station, and the like, and a communication unit 96 for communicating with other devices. The position coordinate P ₁ to P ₃ of the base station 1-3,
Each of them is defined by the equation (11). In addition, the position coordinates P _S of the mobile terminal 10 are defined by Expression (12).

Hereinafter, a positioning process performed by the center station 90 to specify the position of the mobile terminal 10 will be described with reference to FIG. FIG. 3 is a flowchart of the positioning process.

First, in S1, a range difference between the base stations 1 to 3 with respect to the mobile terminal 10 (a difference in physical quantity such as a time difference observed in communication based on a distance difference from the mobile terminal 10 to each base station). To get. Note that the range difference △ ₁₂ ,
△ _23, △ ₃₁ is assumed as defined respectively formula (14).

Next, in S2, the explanation was made in the third prior art.
Thus, based on the PX method,₁~ P _Three, △₁₂, △_{twenty three}, △
₃₁Using P_SX which is the coordinates of₀And y₀Show the relationship
Create a straight line equation. Note that the linear equation can be expressed by equation (50).
Thus, the following equation (53) can be described. Equation (5
In 3), △_{one two Three}, S_{one two Three}, E_ijkIs the formula
Defined in (48), (49) and (52)
Yes, △^t _{one two Three}△_{one two Three}Is a transposed matrix.

[0053]

(Equation 18)

Next, in S3, for each of the three combinations of base station 1 and base station 2, base station 2 and base station 3, and base station 3 and base station 1, range differences △ ₁₂ , △ ₂₃ , △ ₃₁ and based on each of equations (54) to (56), P _S
Create a hyperbola with x ₀ and y ₀ as the coordinates of That is, here, three hyperbolas are created.

[0055]

[Equation 19]

Next, in S4, for each of the three hyperbolas created in S3, the coordinates of the intersection with the straight line created in S2 are determined.

[0057] Here, schematically in Figure 4, position of the mobile terminal 10 of the base station 1 to the base station 3 with (P _S), and a straight line created in three hyperbolas and S2, which have been created in S3 Is shown. In FIG. 4, the hyperbola created from the range difference between the base station 1 and the base station 2 is L (2, 2), and the base station 2 and the base station 3
L (3,3) is the hyperbola created from the range difference of L, and the hyperbola created from the range difference between the base station 3 and the base station 1 is L
(4, 1). Also, L (2,2) and y = ωx
The intersection of + δ is point A, the intersection of L (3,3) and y = ωx + δ is point B, and the intersection of L (4,1) and y = ωx + δ is point C.

Next, at S5, the distances between the points A to C and P _S are respectively set to ε ₁₂ , ε ₂₃ and ε _31, and x ₀ that minimizes the sum of the squares of these is calculated.

Here, the processing in S5 will be specifically described. ε ₁₂ , ε ₂₃ , and ε ₃₁ correspond to the distances of the intersections obtained in S4 from the actual position of the mobile terminal 10, respectively. These are respectively expressed by the formula (5)
It can be described as 7). In each expression of Expression (57),
r _i (x ₀ ) is defined as in equation (58). That is, r _i (x ₀ ) is the distance between the base station i (i = 1, 2, 3) and the mobile terminal 10 (see equation (13)), and the equation (5)
This is shown as a function of the x coordinate (x ₀ ) of the mobile terminal 10 based on 3).

[0060]

(Equation 20)

After deriving ε ₁₂ , ε ₂₃ , and ε ₃₁ as described above, ε shown in equation (59) is introduced. Then, using an appropriate weight matrix W, J is calculated as shown in equation (60). Then, a value of x ₀ that satisfies the expression (61) by differentiating J with x ₀ to become zero is x ₀ calculated in S5. Incidentally, J is a non-linear with respect to x _0, a partial differential equation equation (61) nor in general analytically sought. However, since J has only x ₀ as a variable, the solution of equation (61) can be obtained by changing x ₀ within a predetermined range.

That is, specifically, at S5
X₀Is given by the following expression (63).
J (x) in equation (62)₀X) to minimize₀Becomes What
Here, x shown in equation (63)₀Range is from base station 1 to base
X coordinate of station 3 (x₁, X_Two, X _Three)
Can be That is, in equation (63), x₀m
ax is x₁, X_Two, X_ThreeMaximum value of x₀min is x
₁, X_Two, X_ThreeIs the minimum value of

[0063]

(Equation 21)

Then, in S6, x ₀ calculated in S5 is substituted into equation (53) to obtain y ₀ , thereby identifying the position of the mobile terminal 10 and terminating the process.

In this embodiment described above, S
In 4, the intersections of the straight line created in S2 and the three hyperbolas created in S3 are determined, and in S5, the sum of the squares of the determined three intersections and the actual distance between the mobile terminal 10 is minimized. Thus, the position of the mobile terminal 10 is determined. However, it is also possible to determine an intersection between the above-mentioned straight line and any one of the three hyperbolas, and determine the intersection as the position of the mobile terminal 10. The processing in such a modification will be described with reference to FIG.

In this modified example, in S11, △ ₁₂ , △ ₂₃ , and △ ₃₁ are obtained in the same manner as in S1, and in S12, S2 is obtained.
A straight line is created in the same way as. Then, in S13, S3
An arbitrary one of the three hyperbolas created by the above is created. Then, in S14, the intersection of the straight line created in S12 and the hyperbola created in S13 is determined, the intersection is set as the position of the mobile terminal 10, and the process ends.

Further, as a further modified example of the processing shown in FIG. 3, the intersections of the straight line created in S2 and the two hyperbolas out of the three hyperbolas created in S3 are respectively obtained. The position of the mobile terminal 10 may be determined such that the sum of the square of the distance to the actual mobile terminal 10 is minimized.

The embodiments disclosed this time are to be considered in all respects as illustrative and not restrictive. The scope of the present invention is defined by the terms of the claims, rather than the description above, and is intended to include any modifications within the scope and meaning equivalent to the terms of the claims.

[Brief description of the drawings]

FIG. 1 is a diagram showing a configuration of a communication system according to an embodiment of the present invention.

FIG. 2 is a block diagram of a center station shown in FIG. 1;

FIG. 3 is a flowchart of a positioning process executed by the center station of FIG. 1;

FIG. 4 is a diagram schematically showing three hyperbolas and straight lines created in the positioning process shown in FIG.

FIG. 5 is a flowchart of a modified example of the positioning process of FIG. 3;

FIG. 6 is a diagram for explaining a first conventional technique for the present invention.

FIG. 7 is a diagram for explaining a second conventional technique for the present invention.

FIG. 8 is a diagram for explaining a second conventional technique for the present invention.

FIG. 9 is a diagram for explaining a third conventional technique for the present invention.

FIG. 10 is a diagram for explaining a third conventional technique for the present invention.

[Explanation of symbols]

1-3 base stations, 10 mobile terminals, 90 center stations,
91 CPU, 95 database.

Continuing from the front page (72) Inventor Kimio Fuyo 1-16-20 Minamisenba, Chuo-ku, Osaka City 5th Floor, Miraki Building Lokas Co., Ltd. (72) Inventor Katsuhiko Kumamoto 1-16-20 Minamisenba, Chuo-ku, Osaka City Murakibir 5F Locus Co., Ltd. F term (reference) 5J062 AA09 CC12 EE00 5K067 BB04 DD20 EE02 EE10 EE16 EE24 FF03 GG01 GG11

Claims (3)

[Claims] 1. A mobile terminal location specifying system for specifying a location of a mobile terminal communicating with a first base station, a second base station, and a third base station, wherein the first base station And a center station that communicates with the second base station and the third base station, wherein the center station sets a distance between the first base station and the mobile terminal to a first distance, When the distance between a second base station and the mobile terminal is a second distance, and the distance between the third base station and the mobile terminal is a third distance, the first to third distances From a physical quantity based on the difference, a primary expression creating means for creating a primary equation for the position of the mobile terminal, and from a physical quantity based on the difference between the first to third distances, the position of the mobile terminal A quadratic expression creating means for creating a quadratic expression of: the intersection of the primary expression and the quadratic expression on coordinates , And a position determining means for determining a location of the mobile terminal, location system of the mobile terminal. 2. The center station according to claim 1, further comprising:
Coordinates (x₀, Y₀), The coordinates of the first base station are (x
₁, Y₁), The coordinates of the second base station are (x _Two,
y_Two), The coordinates of the third base station are (x_Three, Y_Three)
Means for defining, between the mobile terminal and the first base station and the mobile terminal
Difference between the time of arrival of information between the base station and the second base station.
Range difference₁₂And the mobile terminal and the second base station
And information between the mobile terminal and the third base station
Range difference 到達_{twenty three}And the mobile terminal
And between the third base station, the mobile terminal and the first
Range difference, which is the difference in arrival time of information between base stations.₃₁
And a means for obtaining₁₂, △_{twenty three}, △₃₁, X₁,
y₁, X_Two, Y_Two, X _Three, And y_ThreeFrom the above x and
Formulas (1) to (3), which are quadratic expressions for y, are created
Then,The primary equation creating means creates Equation (4) as the primary equation, defines ω in Equation (4) according to Equation (5), and defines ω in Equation (5).^t _{one two Three}Is defined by equation (6)._{one two Three}Turn
S in equation (5)_{one two Three}Is defined according to equation (7), δ in equation (4) is defined according to equation (8), and e in equation (8)_ijkIs defined according to equation (9), and f in equation (9)₁ ^Two, F_Two ^Two, F_Three ^TwoIs determined according to equation (10).
Justify,The position determining means is configured to calculate the linear expression, the expression (1) to the expression
(X, y) satisfying at least one of (3)
The coordinates of the mobile terminal (x₀, Y₀) As the moving end
The mobile terminal according to claim 1, wherein the position of the terminal is determined.
Location system. 3. The mobile station of the mobile terminal in a two-dimensional coordinate system (x, y).
Coordinates (x₀, Y₀), The coordinates of the first base station are (x
₁, Y₁), The coordinates of the second base station are (x _Two,
y_Two), The coordinates of the third base station are (x_Three, Y_Three)
Means for defining, between the mobile terminal and the first base station and the mobile terminal
Difference between the time of arrival of information between the base station and the second base station.
Range difference₁₂And the mobile terminal and the second base station
And information between the mobile terminal and the third base station
Range difference 到達_{twenty three}And the mobile terminal
And between the third base station, the mobile terminal and the first
Range difference, which is the difference in arrival time of information between base stations.₃₁
And a means for obtaining₁₂, △_{twenty three}, △₃₁, X₁,
y₁, X_Two, Y_Two, X _Three, And y_ThreeFrom the above x and
Formulas (1) to (3), which are quadratic expressions for y, are created
Then,The primary equation creating means creates Equation (4) as the primary equation, defines ω in Equation (4) according to Equation (5), and defines ω in Equation (5).^t _{one two Three}Is defined by equation (6)._{one two Three}Turn
S in equation (5)_{one two Three}Is defined according to equation (7), δ in equation (4) is defined according to equation (8), and e in equation (8)_ijkIs defined according to equation (9), and f in equation (9)₁ ^Two, F_Two ^Two, F_Three ^TwoIs determined according to equation (10).
I mean,The position deciding means is an intersection of the linear expression and the expression (1).
And the (x₀, Y₀) And ε₁₂, The primary equation and the previous
The intersection of the notation (2) and the (x₀, Y₀) And the distance
ε_{twenty three}, The intersection of the linear equation and the equation (3) and the (x₀,
y₀) And ε ₃₁, The ε₁₂, Ε_{twenty three}, Ε
₃₁Is the minimum of the sum of the squares of (x,
y) is the coordinates of the mobile terminal (x₀, Y₀)
The mobile terminal according to claim 1, wherein a position of the mobile terminal is determined.
Mobile terminal location identification system.