Apparatus and method for estimating position of mobile communication terminal

• US 20020167444A1
• Filed: 04/19/2002
• Published: 11/14/2002
• Est. Priority Date: 04/20/2001
• Status: Active Grant

• Current Assignee: Optis Cellular Technology LLC (Brevet Capital)
• Original Assignee: LG Electronics, Inc. (LG Corporation)
• Inventors: Lee, Yong Woo
• Granted Patent: US 7,057,557 B2
• Time in Patent Office: Days
• US Class Current: 342/387
• CPC Class Codes: H04W 64/00 Locating users or terminals or network equipment for network management purposes, e.g. mobility management

Abstract

A position estimating method and apparatus are disclosed that determine an angle of arrival of a signal received from a terminal; determine a distance of the terminal, using an arrival time difference between the arrival time of the signal and a reference time; and determine a position of the terminal based on the determined angle of arrival and distance.

Claims

1. A position estimating apparatus for a mobile communication terminal, comprising:

a mobile communication exchanger that receives a signal communicated from a mobile communication terminal to a base station;

a position calculation unit that calculates a distance between the mobile communication terminal and the base station using the signal or calculates an arrival angle of the signal received by the base station; and

a position deciding unit that selects a position, determined by combining positional values calculated in the position calculation unit, as an approximate position of the mobile communication terminal.

2. The apparatus of claim 1, wherein the position calculation unit comprises:

an angle of arrival (AOA) calculation unit that calculates an arrival direction of the received signal; and

at least one of (a) and (b);

(a) a time of arrival (TOA) calculation unit that calculates the distance between the mobile communication terminal and the base station using an arrival time of the received signal,

(b) a time difference of arrival (TDOA) calculation unit that calculates the distance between the mobile communication terminal and the base station using an arrival time difference of the received signal.

3. The apparatus of claim 2, wherein the mobile communication exchanger selectively transmits the signal received by the base station to the AOA calculation unit and at least one of the TOA calculation unit and the TDOA calculation unit.

4. The apparatus of claim 2, wherein the position deciding unit selects an average value of the positional values as the approximate position of the mobile communication terminal, each positional value determined from the signal received by a different one of a plurality of base stations and each positional value identified by the intersection of a virtual circle, having a radius substantially equivalent to the corresponding distance calculated in the TOA calculation unit and centered about the position of the respective base station, and a virtual ray drawn from the position of the respective base station toward the corresponding arrival direction found in the AOA calculation unit.

5. The apparatus of claim 4, wherein each respective radius is determined by multiplying the corresponding arrival time by an electric wave speed.

6. The apparatus of claim 1, wherein the position deciding unit compares total lengths of vertical lines after drawing vertical lines toward virtual lines connecting positions calculated in the TDOA calculation unit and in the AOA calculation unit, respectively, and then decides the approximate position based on the shorter total length of the vertical lines.

7. A position estimating apparatus for a mobile communication terminal, comprising:

a mobile communication exchanger that receives a signal of a mobile communication terminal, through a plurality of base stations;

a time of arrival (TOA) calculation unit that, for each of the plurality of base stations, calculates a distance between the mobile communication terminal and the respective base station, using an arrival time of the signal at the respective base station;

an angle of arrival (AOA) calculation unit that, for each of the plurality of base stations, calculates a direction of the mobile communication terminal based on an angle of arrival of the signal received by the respective base station; and

a position deciding unit that estimates an approximate position of the mobile terminal by averaging positional coordinates determined from the corresponding distances and angles of arrival.

8. A position estimating apparatus for a mobile communication terminal, comprising:

a mobile communication exchanger that receives a signal of a mobile communication terminal, through a plurality of base stations;

a time difference of arrival (TDOA) calculation unit that calculates a distance between the mobile terminal and each of the base stations using the difference in an arrival time of the signal at the respective base stations;

an angle of arrival (AOA) calculation unit that calculates an angle of arrival between the mobile terminal and each of the base stations using an arrival angle of the signal at the respective base stations; and

a position deciding unit that estimates the position of the mobile terminal by comparing the calculated distance values of the TDOA calculation unit and the angle of arrival values of the AOA calculation unit.

9. A position estimating method for a mobile communication terminal, comprising:

measuring an arrival angle of a signal communicated between the mobile terminal and a base station;

measuring a distance of the mobile terminal using an arrival time or an arrival time difference of the signal communicated between the mobile terminal and the base station; and

deciding a position of the mobile terminal by combining the arrival angle and the distance.

10. The method of claim 9, wherein deciding the position of the mobile terminal further comprises:

(a) creating a virtual circle, centered around the base station, having a radius determined from the arrival time of the signal;

(b) forming a virtual ray from the base station along the arrival angle of the signal;

(c) setting a position where the virtual circle and the virtual ray cross as an estimated position of the mobile terminal;

(d) performing (a) through (c) for the signal received by each of a plurality of base stations; and

(e) deciding an average coordinate value for the respective estimated positions, determined for the plurality of base stations, as a final position of the mobile terminal.

11. The method of claim 9, wherein deciding the position of the terminal further comprises:

setting a first virtual line from a present position of the mobile terminal, measured using the arrival time difference of the signal, toward the position of the mobile terminal similarly measured a predetermined time earlier;

setting a second virtual line from a present position of the mobile terminal, measured using the arrival angle of the signal, toward the position of the mobile terminal similarly measured a predetermined time earlier;

drawing first vertical line segments from first estimated positions of the mobile terminal toward the first virtual line and finding a first total length of the first vertical line segments;

drawing second vertical line segments from second estimated positions of the mobile terminal toward the second virtual line and finding a second total length of the second vertical line segments; and

deciding the position of the mobile terminal based on the lesser value of the first and second total lengths.

13. The method of claim 12, wherein the respective radius of each of the virtual circles is set by multiplying the corresponding measured arrival time of the signal by a speed of an electric wave.

15. The method of claim 14, further comprising:

performing (a) and (b) in at least three separate time periods; and

determining an approximate position of the terminal using the angles of arrival and distances determined in the at least three time periods.

16. The method of claim 15, wherein the angles of arrival and distances, determined in the at least three time periods, are evaluated through a liner regression analysis to determine the approximate position of the terminal.

18. The method of claim 17, further comprising:

performing (a) through (d) in at least three separate time periods; and

determining an approximate position of the terminal using the first and second positions determined in the at least three time periods.

19. The method of claim 18, wherein the positions, determined in the at least three time periods, are evaluated through a liner regression analysis to determine the approximate position of the terminal.

20. The method of claim 18, further comprising:

representing the first and second positions determined in the at least three time periods by graphical coordinates;

forming a first virtual line connecting the graphical coordinates of the first positions determined in a first time period and a second time period;

forming a second virtual line connecting the graphical coordinates of the second positions determined in a first time period and a second time period, wherein the first and second time periods used to form the second virtual line may or may not be the same time periods as the first and second time periods used to form the first virtual line;

forming first virtual vertical line segments between the graphical coordinates of the first positions determined in every time period, except the first and second time periods used to form the first virtual line, and the first virtual line;

forming second virtual vertical line segments between the graphical coordinates of the second positions determined in every time period, except the first and second time periods used to form the second virtual line, and the second virtual line;

summing the length values of the first virtual line segments to produce a first sum;

summing the length values of the second virtual line segments to produce a second sum; and

determining the approximate position of the terminal based on the lesser value of the first and second sums.

21. The method of claim 20, wherein:

the approximate position of the terminal is identified by the first position of the last of the at least three time periods, if the first sum is less than the second sum; and

the approximate position of the terminal is identified by the second position of the last of the at least three time periods, if the first sum is less than the second sum.

22. The method of claim 17, further comprising:

transmitting a message to the terminal requesting the terminal'"'"'s location; and

transmitting the signal from the terminal in response to the message.

24. The method of claim 23, further comprising:

performing (a) through (c) for the signal received by each of a plurality of base stations; and

determining an approximate position of the terminal by combining the positions determined for the plurality of base stations.

25. The method of claim 24, further comprising:

representing each of the positions determined with respect to the plurality of base stations by {X, Y} graphical coordinates;

averaging the values of the X coordinates and the values of the Y coordinates; and

determining the approximate location based on the average value of the X coordinates and the average value of the Y coordinates.

12. A position estimating method for a mobile communication terminal, comprising:

(a) measuring an angle to a mobile communication terminal using an arrival angle of a signal communicated between the mobile terminal and a base station;

(b) measuring a distance of the mobile terminal using an arrival time of the signal communicated between the mobile terminal and the base station;

(c) drawing a virtual circle using the distance as a radius and centering the virtual circle around the base station;

(d) drawing a ray from the center of the virtual circle toward the arrival angle direction;

(e) setting a position where the circle and the ray cross as an estimated position;

(f) performing (a) through (e) for the signal received by each of a plurality of base stations; and

(g) deciding an average coordinate value of the plurality of estimated positions as a final position of the mobile terminal.

14. A position estimating method, comprising:

(a) determining an angle of arrival of a signal received from a terminal;

(b) determining a distance of the terminal, using an arrival time difference between the arrival time of the signal and a reference time; and

(c) determining a position of the terminal based on the determined angle of arrival and distance.

17. A position estimating method, comprising:

(a) determining, for each of a plurality of base stations, an angle of arrival of a signal received from a terminal;

(b) determining, for each of the plurality of base stations, a distance of the terminal, using an arrival time difference between the arrival time of the signal and a reference time;

(c) determining a first position of the terminal based on the plurality of determined angles of arrival; and

(d) determining a second position of the terminal based on the plurality of determined distances.

23. A position estimating method, comprising:

(a) determining an angle of arrival of a signal received from a terminal;

(b) determining a distance of the terminal, using an arrival time of the signal; and

(c) determining a position of the terminal based on the determined angle of arrival and distance.