System and Method for Total Flight Time Ratio Pattern Matching

• US 20120149390A1
• Filed: 05/20/2011
• Published: 06/14/2012
• Est. Priority Date: 12/09/2010
• Status: Active Grant

• Current Assignee: Bison Patent Licensing, LLC
• Original Assignee: Andrew LLC (CommScope Holding Company, Inc.)
• Inventors: Gravely, Thomas B., Alles, Martin, Al-Mufti, Khalid W., Kalenahalli, Suryanarayana
• Granted Patent: US 8,489,122 B2
• Time in Patent Office: Days
• US Class Current: 455/456.1
• CPC Class Codes: G01S 5/14 Determining absolute distances from a plurality of spaced points of known location
• CPC Class Codes: H04W 64/00 Locating users or terminals or network equipment for network management purposes, e.g. mobility management

Abstract

A method and system for estimating the location of a mobile device. A range of the mobile device to a reference station may be determined as a function of the time of transmission of a first signal transmitted from a base station and as a function of the time of receipt of a second signal transmitted from the mobile device to the reference station, the second signal being a function of the first signal advanced by a timing parameter. A relationship for each of a plurality of grid points in a geographic region may be determined as a function of the determined range and a range metric. These plural grid points may contain the reference station. The determined relationship may be compared with data corresponding to each of the plural grid points, and a location of the mobile device determined as a function of the comparison.

Claims

1. A method of estimating the location of a mobile device comprising the steps of:

(a) determining the time of transmission of a first signal from a base station;

(b) receiving the first signal at the mobile device;

(c) transmitting a second signal from the mobile device, the second signal being a function of the first signal advanced by a timing parameter;

(d) determining a time of receipt of the second signal at a first reference station;

(e) determining a first range of the mobile device from the first reference station as a function of the determined time of transmission of the first signal and the determined time of receipt of the second signal;

(f) providing a plurality of grid points in a geographic region, the plurality of grid points containing the first reference station;

(g) determining a first relationship between the determined first range and a first range metric for each of the plurality of grid points;

(h) determining a second relationship for each of the plurality of grid points;

(i) comparing the first and second relationships; and

(j) determining a location of the mobile device as a function of the comparison of the first and second relationships.

2. The method of claim 1 further comprising the step of adjusting the determined first range as a function of the presence of multipath.

3. The method of claim 1 further comprising the steps of:

(k) determining a time of receipt of the second signal at a plurality of reference stations;

(l) determining additional ranges of the mobile device to the plurality of reference stations as a function of the determined time of transmission of the first signal and determined times of receipt of the second signal at the plurality of reference stations; and

(m) providing a plurality of grid points in a geographic region, the plurality of grid points containing the plurality of reference stations.

4. The method of claim 3 further comprising the step of adjusting the determined additional ranges as a function of the presence of multipath.

5. The method of claim 4 wherein the adjustments to the additional ranges are different from each other.

6. The method of claim 1 wherein one of the plurality of grid points corresponds to the first reference station.

7. The method of claim 3 wherein each reference station corresponds to a grid point.

8. The method of claim 1 wherein one of the plurality of grid points is randomly located within the geographic region.

9. The method of claim 1 wherein one of the plurality of grid points is located on a predetermined fixed uniform grid defined over the geographic region.

10. The method of claim 1 wherein the time of transmission of the first signal is determined from the time of transmission of a marker in the first signal.

11. The method of claim 1 wherein the step of determining a first relationship further comprises determining a ratio of the determined first range of the mobile device with a weighted metric of the determined first range for each of the plurality of grid points.

12. The method of claim 1 wherein the second relationship is determined using an ideal range between the first reference station and a grid point.

13. The method of claim 1 wherein the step of comparing further comprises comparing the determined first relationship with second relationships provided from a database of historical data, from a database substantially populated in real-time, or from a combination of a database of historical data and a database substantially populated in real-time.

14. The method of claim 1 wherein the timing parameter is determined as a function of a timing advance (TA) or the position of a physical channel frame marker.

15. A method of estimating the location of a mobile device comprising the steps of:

(a) determining a range of a mobile device to a reference station as a function of the time of transmission of a first signal transmitted from a base station and as a function of the time of receipt of a second signal transmitted from the mobile device to the reference station, the second signal being a function of the first signal advanced by a timing parameter;

(b) providing a plurality of grid points in a geographic region, the plurality of grid points containing the reference station;

(c) determining a relationship for each of the plurality of grid points as a function of the determined range and a range metric;

(d) comparing the determined relationship with data corresponding to each of the plural grid points; and

(e) determining a location of the mobile device as a function of the comparison.

16. The method of claim 15 further comprising the step of adjusting the determined range as a function of the presence of multipath.

17. The method of claim 15 wherein the step of determining a range further comprises:

(i) determining a time of receipt of the second signal at a plurality of reference stations; and

(ii) determining additional ranges of the mobile device to the plurality of reference stations as a function of the determined time of transmission of the first signal and as a function of the determined times of receipt of the second signal.

18. The method of claim 17 further comprising the step of adjusting the determined additional ranges as a function of the presence of multipath.

19. The method of claim 18 wherein the adjustments to the additional ranges are different from each other.

20. A system for estimating the location of a mobile device comprising:

(a) circuitry for determining a range of a mobile device to a reference station as a function of the time of transmission of a first signal transmitted from a base station and as a function of the time of receipt of a second signal transmitted from the mobile device to the reference station, the second signal being a function of the first signal advanced by a timing parameter;

(b) a processor for determining a plurality of grid points in a geographic region, the plurality of grid points containing the geographic location of the reference station;

(c) circuitry for determining a relationship for each of the plurality of grid points as a function of the determined range and a range metric;

(d) circuitry for comparing the determined relationship with data corresponding to each of the plural grid points; and

(e) circuitry for determining a location of the mobile device as a function of the comparison.

21. In a method for estimating the location of a mobile device in a geographic region, the method including determining a range of a mobile device to a reference station as a function of the time of transmission of a first signal transmitted from a base station and received by the mobile device and as a function of a second signal transmitted from the mobile device to a reference station, the second signal being a function of the first signal advanced by a timing parameter, the improvement comprising:

defining the geographic region by a plurality of grid points;

determining a relationship for each of the plurality of grid points as a function of the determined range and a range metric;

comparing the determined relationship with data corresponding to each of the plurality of grid points to determine a location of the mobile device; and

determining a location of the mobile device as a function of the comparison.

22. The method of claim 21 further comprising the step of adjusting the determined range as a function of the presence of multipath.