Positioning system and position calculating method in mobile communication system

• US 6,845,239 B1
• Filed: 11/15/2000
• Issued: 01/18/2005
• Est. Priority Date: 11/15/1999
• Status: Active Grant

• Current Assignee: Kokusai Electric Co., Ltd.
• Original Assignee: Kokusai Electric Co., Ltd.
• Inventors: Oyamada, Ouichi, Hirata, Shinichi, Sato, Tsuyoshi
• Primary Examiner(s): Hudspeth, David
• Assistant Examiner(s): Afshar, Kamran
• Application Number:
  US09/712,242
• Time in Patent Office: 1,525 Days
• Field of Search: 455/456.1, 455/456.2, 455/456.3, 455/456.4, 455/456.5, 455/456.6, 455/457, 455/422.1, 455/502, 455/404.2, 455/427, 455/4, 455/67.11, 455/500, 340990-99519, 701200-206, 709/218, 34235701-35717, 342/457, 342/463, 342/464
• US Class Current: 455/456.1
• CPC Class Codes: G01S 2205/008 using a mobile telephone network
• CPC Class Codes: G01S 5/0027 of actual mobile position, i.e. position determined on mobile
• CPC Class Codes: G01S 5/06 Position of source determined by co-ordinating a plurality of position lines defined by path-difference measurements G01S5/12 takes precedence
• CPC Class Codes: H04W 64/00 Locating users or terminals or network equipment for network management purposes, e.g. mobility management

Abstract

A positioning system and a position calculating method in a mobile communication system for specifying a position of a mobile station unit on the basis of positional information from three base station units and for displaying related map information on the mobile station unit to utilize the positional information effectively, the position system and the position calculating method in which a position reporting means of a base station unit reports positional information, a distance difference calculating means of the mobile station unit calculates differences in distance between the mobile station unit and three base station units on the basis of the positional information from the three base station units, measures a position of the mobile station unit on the basis of the positional information and the distance differences by using a position measuring means, reports the measured position to an exchange unit by using a position reporting means, and a map information displaying means of the mobile station unit displays related map information reported from the exchange unit.

Claims

1. A positioning system in a mobile communication system comprising a stationary station unit and a mobile station unit,

wherein said stationary station unit reports its positional information to said mobile station unit;

and

wherein said mobile station unit calculates differences in distance between said mobile station unit and three stationary station units on the basis of positional information reported from said stationary station units and phase differences between said measured stationary station units, calculates a position of the mobile station unit on the basis of said differences in distance until predetermined minimum correction values of positional information of the mobile station unit are obtained.

2. A positioning system in a mobile communication system comprising a stationary station unit and a mobile station unit,

wherein said stationary station unit reports its positional information to said mobile station unit;

and

wherein said mobile station unit calculates differences in distance between said mobile station unit and three stationary station units on the basis of positional information reported from said stationary station units and phase differences between said measured stationary station units, calculates average values of the positions of said three stationary units as assumed values x′

, v′ and

z′

, calculates correction values on the basis of the differences in distance and the assumed values, updates the assumed values by adding the calculated correction values, repeats the calculations of the correction values and updates the assumed values until the calculated correction values satisfy a specific condition, and determines the updated assumed values as a position x, y and z of the mobile station unit when the correction values satisfy the specific condition.

5. The positioning system in a mobile communication system according to claim 2,

wherein the specific condition is that absolute values of the correction values are smaller than 1.

3. A positioning system in a mobile communication system, comprising an exchange unit, a base station unit, and a mobile station unit,

wherein said base station unit transmits positional information of the base station unit to the mobile station unit;

wherein said mobile station unit calculates differences in distance between said mobile station unit and three base station units on the basis of positional information transmitted from said base station units and phase differences between said measured base station units, calculates a position of the mobile station unit on the basis of said differences in distance until predetermined minimum correction values of positional information of the mobile station unit are obtained, transmits the information of said position to said exchange unit, and displays obtained received map information from said exchange unit; and

wherein said exchange unit stores map information, obtains corresponding map information from said stored map information on the basis of said positional information transmitted from said mobile station unit, and transmits the map information to transmit it to said mobile station unit.

4. A positioning system in a mobile communication system, comprising an exchange unit, a base station unit, and a mobile station unit,

wherein said base station unit transmits positional information of the base station unit to the mobile station unit;

wherein said mobile station unit calculates differences in distance between said mobile station unit and three base station units on the basis of positional information transmitted from said base station units and phase differences between said measured base station units, calculates average values of the positions of said three base station units as assumed values x′

, y′ and

z′

, calculates correction values on the basis of the differences in distance and the assumed values, updates the assumed values by adding the calculated correction values, repeats the calculations of the corrected values and updates the assumed values until the calculated correction values satisfy a specific condition, determines the updated values as a position x, y and z of the mobile station unit when the correction values satisfy the specific condition, transmits information of the determined position to said exchange unit, and displays received map information from said exchange unit; and

wherein said exchange unit stores map information, obtains corresponding map information from the stored map information on the basis of the positional information transmitted from said mobile station unit, and transmits the map information to said mobile station unit.

6. A position calculating method for calculating a position of a mobile station unit, comprising the steps of:

obtaining positional information (X1, Y1, Z1) of a first base station, positional information (X2, Y2, X2) of a second base station, and positional information (X3, Y3, Z3) of a third base station unit;

calculating differences in distance between the mobile station unit and said base station units L1−

L2(=V×

d1/R) and L1−

L3(=V×

d2/R), L2−

L3(=V×

d3/R) by using the radio wave propagation speed V and the number of chips per unit time of a spread code R on the basis of phase differences d1, d2, and d3 between said base station units;

calculating average values x′

=(X1+X2+X3)/3, y′

=(Y1+Y2+Y3)/3, z′

=(Z1+Z2+Z3)/3 of positions of said three base station units as initialization;

where x=x′

+dx, y=y′

+dy, and z=z′

+dz if (x, y, z) is expressed by using corrected values dx, dy, and dz of x, y, and z for the position (x, y, z) of a required mobile station unit and said x′

, y′ and

z′

;

calculating dx and dy with linearization with a Taylor expansion supposing that dx, dy, and dz are sufficiently smaller than x, y, and z on the basis of these equations of x, y, and z and an equation in which said differences in distance are expressed with said positions of said three base station units (x, y, z), by using a determinant of a conventional equation AΔ

=F obtained assuming that said phase difference error is 0 (where A denotes a matrix represented by coefficients when representing the differences in distance between said mobile station unit and said base station units by dx, dy, and dz, Δ

denotes a matrix of dx, dy, and dz, and F is a matrix related to said differences in distance);

substituting said calculated dx and dy into said equations x=x′

+dx and y=y′

+dy to obtain x and y and further calculating dx and dy using said conditional expression AΔ

=F assuming that the obtained x, y to be x′

, y′

; and

calculating the position of said mobile station unit by repeating said calculation until absolute values |dx| and |dy| of said calculated dx and dy become smaller than 1 to consider the values of x′ and

y′

obtained when |dx| and |dy| become smaller than 1 to be x, y coordinates and by evaluating the z coordinate from z=(Z1+Z2+Z3)/3.

7. The position calculating method according to claim 6 for calculating the position of said mobile station unit supposing said determinant AΔ

=F to be a conditional expression,

wherein, supposing that the distances between the mobile station unit and the base station units are L1, L2, and L3, the differences in distance between said mobile station unit and said base station units can be expressed by D1=L1−

L2, D2=L1−

L3, and D3=L2−

L3;

wherein the differences in distance can be expressed by using the phase differences d1, d2, and d3 between said base station units, the radio wave propagation speed V, the number of chips per unit time of a spread code R, and residuals v1, v2, and v3 given by measurement errors of said phase differences as follows;

D1=L1−

L2=V×

d1/R+v1

D2=L1−

L3=V×

d2/R+v2

D3=L2−

L3=V×

d3/R+v3;

wherein further said differences in distance can be expressed on the basis of the positional coordinates (X1, Y1, Z1), (X2, Y2, Z2), and (X3, Y3, Z3) of three base station units and the positional coordinates (x, y, z) of said mobile station unit as follows;

$\begin{array}{c}\mathrm{D1}=\mathrm{L1}-\mathrm{L2}=<br><br>{\left\{{\left(\mathrm{X1}-x\right)}^2+{\left(\mathrm{Y1}-y\right)}^2+{\left(\mathrm{Z1}-z\right)}^2\right\}}^{1/2}-\\ <br><br>{\left\{{\left(\mathrm{X2}-x\right)}^2+{\left(\mathrm{Y2}-y\right)}^2+{\left(\mathrm{Z2}-z\right)}^2\right\}}^{1/2}\end{array}$$\begin{array}{c}\mathrm{D2}=\mathrm{L1}-\mathrm{L3}=<br><br>{\left\{{\left(\mathrm{X1}-x\right)}^2+{\left(\mathrm{Y1}-y\right)}^2+{\left(\mathrm{Z1}-z\right)}^2\right\}}^{1/2}-\\ <br><br>{\left\{{\left(\mathrm{X3}-x\right)}^2+{\left(\mathrm{Y3}-y\right)}^2+{\left(\mathrm{Z3}-z\right)}^2\right\}}^{1/2}\end{array}$$\begin{array}{c}\mathrm{D3}=\mathrm{L2}-\mathrm{L3}=<br><br>{\left\{{\left(\mathrm{X2}-x\right)}^2+{\left(\mathrm{Y2}-y\right)}^2+{\left(\mathrm{Z2}-z\right)}^2\right\}}^{1/2}-\\ <br><br>{\left\{{\left(\mathrm{X3}-x\right)}^2+{\left(\mathrm{Y3}-y\right)}^2+{\left(\mathrm{Z3}-z\right)}^2\right\}}^{1/2};<br><br>\end{array}$

wherein x, y, and z can be expressed by using assumed values x′

, y′ and

z′ and

their corrected values dx, dy, and dz as follows;

x=x′

+dx

y=y′

+dy

z=z′

+dz

wherein, substituting said equations of x, y, and z into said equations of D1, D2, and D3 and determining that dx, dy, and dz are sufficiently smaller than x, y, and z, they can be linearized using Taylor expansions as follows;

D1=S1−

S2+a1·

dx+b1·

dy+c1·

dz−

(a2·

dx+b2·

dy+c2·

dz)

D2=S1−

S3+a1·

dx+b1·

dy+c1·

dz−

(a3·

dx+b3·

dy+c3·

dz)

D3=S2−

S3+a2·

dx+b2·

dy+c2·

dz−

(a3·

dx+b3·

dy+c3·

dz)

 

wherein Si={(Xi−

x′

)²+(Yi−

y)²+(Zi−

z)²}^1/2

wherein the following observation equations are derived from the above;

v1=(a1−

a2)dx+(b1−

b2)dy+(c1−

c2)dz+S1−

S2−

V×

d1/R

v2=(a1−

a3)dx+(b1−

b3)dy+(c1−

c3)dz+S1−

S3−

V×

d2/R

v3=(a2−

a3)dx+(b2−

b3)dy+(c2−

c3)dz+S2−

S3−

V×

d3/R

 

wherein if v=0 said observation equations can be expressed as follows;

(a1−

a2)dx+(b1−

b2)dy+(c1−

c2)dz=V×

d1/R−

S1+S2

(a1−

a3)dx+(b1−

b3)dy+(c1−

c3)dz=V×

d2/R−

S1+S3

(a2−

a3)dx+(b2−

b3)dy+(c2−

c3)dz=V×

d3/R−

S2+S3

wherein said three equations can be expressed in the following determinant;

AΔ

=F

 

where A is a matrix with a1, a2, a3, b1, b2, b3, c1, c2, and c3, Δ

is a matrix with dx, dy, and dz, F is a matrix with V, d1, d2, d3, S1, S2, and S3.

8. A position calculating method of a positioning system in a mobile communication system comprising a base station unit and a mobile station unit, the method comprising the steps of:

calculating differences in distance between the mobile station unit and three base station units on the basis of positional information reported from said three base station units and phase differences between the measured base station units;

setting an estimated distance between said mobile station unit and a first base station unit to an assumed distance as initialization;

assuming also distances between said mobile station unit and other base station units on the basis of the assumed distance;

calculating an assumed position of the mobile station unit by using the assumed distances between the mobile station unit and the base station units and the positional information reported from the base station units;

repeating the calculation with a feedback from a calculated distance to an assumed distance until a difference is decreased to be lower than a specific value between the calculated distance to the first base station unit obtained on the basis of the calculated assumed position and the assumed distance to the first base station unit; and

determining an assumed position obtained when the difference between the calculated distance and the assumed distance becomes sufficiently lower than the specific value to be a position of the mobile station unit.

9. A position calculating method comprising the steps of:

obtaining positional information (X1, Y1, Z1) of a first base station unit, positional information (X2, Y2, Z2) of a second base station unit, and positional information (X3, Y3, Z3) of a third base station unit;

calculating differences in distance L1−

L2(=V×

d1/R) and L1−

L3(=V×

d2/R) between a mobile station unit and said base station units on the basis of phase differences d1, d2, and d3 between said base station units by using the radio wave propagation speed V and the number of chips per unit time of a spread code R;

setting an estimated value 1 of the distance between said mobile station unit and said first base station unit to an assumed distance L1 as initialization;

evaluating assumed distances L2 and L3 between said mobile station unit and other base station units by using said L1 and the equations of the differences in distance between said mobile station unit and said base station units;

evaluating as assumed position x, y of said mobile station unit on the basis of said L1, L2, and L3 obtained and the positional information of said base station units;

evaluating a distance L1′

between said evaluated x, y and said positional information (X1, Y1) of said first base station as a calculated distance on the basis thereof;

substituting said L1′

into L1 until an absolute value of the distance between said assumed distance L1 and said calculated distance L1′

is smaller than a specific value and repeating said calculation; and

specifying the assumed position x, y corresponding to the absolute value of said difference smaller than the specific value as a position of said mobile station unit.

10. The position calculating method according to claim 9, wherein the distance evaluated on the basis of the propagation loss from the first base station unit to the mobile station unit is specified as an estimated value 1 of the distance between said mobile station unit and said first base station unit for initialization in L1.

11. A positioning system in a mobile communication system comprising a stationary station unit and a mobile station unit,

wherein said stationary station unit reports positional information thereof to said mobile station unit;

and

wherein said mobile station unit calculates differences in distance between said mobile station unit and three stationary station units on the basis of positional information of said three stationary station units reported therefrom and phase differences between the measured stationary station units, calculates a position of the mobile station unit on the basis of the positional information of said stationary station units and said differences in distance, stores the calculated positional information of said mobile station unit as previous positional information, and subsequently calculates differences in distance between said mobile station unit and two stationary station units on the basis of the positional information of said two stationary station units reported therefrom and phase differences between said measured two stationary station units, calculates a position of the mobile station unit on the basis of the positional information of said stationary station units, said differences in distance, and said stored previous positional information of said mobile station unit, and stores information of said calculated position as previous positional information.

12. The positioning system according to claim 11,

wherein said mobile station unit reports the information of the calculated position to said stationary station units;

wherein said stationary station units reports corresponding user information to said mobile station unit on the basis of said reported positional information of said mobile station unit; and

wherein said mobile station unit displays said user information reported from said stationary station units.

13. A positioning system in a mobile communication system comprising an exchange unit, a base station unit, and a mobile station unit,

wherein said base station unit transmits positional information of the corresponding base station unit to the mobile station unit;

wherein said mobile station unit calculates differences in distance between said mobile station unit and three base station units on the basis of positional information of said base station units transmitted therefrom and phase differences between said measured base station units, calculates a position of the mobile station unit on the basis of said positional information of said base station units and said differences in distance, stores said calculated positional information of the mobile station unit as previous positional information, and subsequently calculates differences in distance between said mobile station unit and two base station units on the basis of positional information of said two base station units reported therefrom and phase differences between said two base station units, calculates a position of the mobile station unit on the basis of said positional information of said base station units, said differences in distance, and said stored previous positional information of the mobile station unit, stores information of said calculated position as previous positional information, transmits the information of the calculated position to said exchange unit, and displays received user information; and

wherein said exchange unit previously stores user information related to the positional information from said mobile station unit and obtains corresponding user information from said stored user information on the basis of the positional information transmitted from said mobile station unit to transmit it to said mobile station unit.

14. A positioning system in a mobile communication system comprising an exchange unit, a base station unit, a mobile station unit,

wherein said base station unit comprises position reporting means for reporting positional information of the corresponding base station unit to said mobile station unit and user information reporting means for reporting user information reported from said exchange unit to the corresponding mobile station unit;

wherein said mobile station unit comprises 3-point position measuring means for calculating differences in distance between said mobile station unit and three base station units on the basis of positional information of said three base station units reported therefrom and phase differences between said measured base station units and for calculating a position of the mobile station unit on the basis of said positional information and said differences in distance to store it as previous positional information, 2-point position measuring means for calculating differences in distance between said mobile station unit and two base station units on the basis of positional information of said two base station units reported therefrom and phase differences between said measured two base station units and for calculating a position of the mobile station unit on the basis of said positional information of said base station units, said differences in distance, and said stored previous positional information of the mobile station unit to store it as previous positional information, position reporting means for outputting information of the calculated position for displaying and reporting it to said exchange unit, and user information displaying means for displaying information of said output position for displaying and user information reported from said exchange unit; and

wherein said exchange unit obtains corresponding user information from user information storing means on the basis of the information from said user information storing means for storing user information and the information of the position reported from said mobile station unit and reports it to said mobile station unit via said base station units.

15. A positioning system in a mobile communication system comprising an exchange unit, a base station unit, and a mobile station unit,

wherein said base station unit comprises a control section for outputting positional information representing a position of the base station unit and obtaining positional information of a position of the mobile station unit therefrom, a circuit control section for transmitting said positional information of said mobile station unit to said exchange unit and receiving user information from said exchange unit, a signal processing section for modulating said positional information of the base station units and said user information with a spread code and demodulating said received positional information of said mobile station unit with said spread code, and a transmit-receive amplification section for transmitting said modulated signal and receiving said positional information from said mobile station unit;

wherein said mobile station unit comprises a transmit-receive amplification section for receiving said signal transmitted from said base station unit and transmitting the signal to said base station unit, a signal processing section for performing synchronization of the received signal and demodulation with said spread code, for outputting positional information from three or two base station units, and for modulating positional information of the mobile station unit with said spread code in order to measure phase differences between respective base station units and to transmit the calculated positional information of the mobile station unit to said exchange unit via said base station units, a control section for calculating differences in distance between said mobile station unit and said three base station units on the basis of the phase differences between said three base station units, for calculating a position of the mobile station unit on the basis of the positional information of said there base station units and said differences in distance to store it as previous positional information, for subsequently calculating differences in distance between said mobile station unit and said two base station units on the basis of the phase differences between said two base station units, and for calculating a position of the mobile station unit on the basis of the positional information of said two base station units, said differences in distance, and said previous positional information, a storing section for storing said calculated positional information of the mobile station unit as previous positional information, and a displaying section for displaying said calculated positional information and said user information transmitted from said exchange unit; and

wherein said exchange unit comprises a user information storing section for storing the user information, a circuit control section for receiving said positional information of said mobile station unit from said base station unit and transmitting said user information, and an exchange control section for obtaining related user information from said user information storing section on the basis of said received positional information of the mobile station unit and outputting it to said circuit control section.

16. A position calculating method of a positioning system in a mobile communication system comprising a base station unit and a mobile station unit, comprising the steps of:

calculating a position of the mobile station unit on the basis of positional information reported from three base station units and phase differences between measured base station units and storing information of said calculated position as previous positional information (x′

, y′

);

subsequently calculating differences in distance between said mobile station unit and respective base station units on the basis of positional information reported from two base station units and phase differences between said measured base station units and using said stored previous positional information (x′

, y′

) as initialization of an estimated distance of the required mobile station unit;

specifying corrected values dx, dy from information of said estimated position (x′

, y′

) for a position (x, y) of the required mobile station unit;

calculating dx, dy by linearization with a Taylor expansion determining that dx and dy are sufficiently low relative to x and y on the basis of the distance evaluated from the estimated position and the positions of said two base station units, and the differences in distance between the mobile station unit and the base station units evaluated from said measured phase differences;

evaluating a calculated position (x, y) by using said calculated dx and dy and using said evaluated x and y as an estimated position (x′

, y′

); and

repeating the calculation with feedback from said calculated position to the estimated position until said calculated dx and dy become smaller than a specific value or up to the specific number of calculations and specifying the calculated position (x, y) corresponding to dx and dy smaller than said specific value or obtained after the repetitions by the specific number of calculations as a position of the mobile station unit.

17. A position calculating method of positioning system in a mobile communication system comprising a base station unit and a mobile station unit, comprising the steps of:

storing a position of a mobile station unit obtained on the basis of positional information of three base station units and phase differences between said base station units as previous positional information (x′

, y′

);

obtaining positional information (X1, Y1) of a first base station unit and positional information (X2, Y2) of a second base station unit;

calculating a difference in distance L1−

L2(=V×

d1/R) between the mobile station unit and each of said base station units by using radio wave propagation speed V and the number of chips per unit time of a spread code R from a phase difference d1 between said base station units;

using said stored positional information (x′

, y′

) as initialization of an estimated position of the required mobile station unit;

having x=x′

+dx and y=y′

+dy when (x, y) is expressed by using the corrected values dx and dy for the position (x, y) of the required mobile station unit and said estimated position (x′

, y′

);

calculating dx and dy by linearization with a Taylor expansion determining that dx and dy are sufficiently smaller than x and y from these equations of x and y and equations expressing said distance between the mobile station unit and each of said base station units by using the positions of said two base station units and the estimated position (x′

, y′

);

substituting said calculated dx and dy into said equations x=x′

+dx and y=y′

+dy to evaluate the calculated position (x, y); and

repeating said calculation by using said evaluated calculated position (x, y) as the estimated position (x′

, y′

) until absolute values |dx| and |dy| of said calculated dx and dy become smaller than 1 or up to the specific number of calculations and specifying the calculated position (x, y) corresponding to |dx| and |dy| smaller than 1 or obtained after said specific number of calculations as a position of said mobile station unit.