Navigation system

• US 8,010,133 B2
• Filed: 01/03/2008
• Issued: 08/30/2011
• Est. Priority Date: 02/17/2004
• Status: Expired due to Fees

• Current Assignee: Hailo Technologies, LLC (2S Ventures, LLC)
• Original Assignee: NAV-Track, Inc.
• Inventors: Cheok, Ka C., Smid, G. Edzko
• Primary Examiner(s): MEHRPOUR, NAGHMEH
• Application Number:
  US11/968,884
• Publication Number:
  US 20080103696A1
• Time in Patent Office: 1,335 Days
• Field of Search: 4554561-4565, 455/67.11, 370/69.1, 370/70, 342/387, 342/359.09, 342/357.02, 342/357.906, 342/357.03, 342/127, 342/174, 342/457, 342/352.07, 342/103, 342/257.08, 342/357.17, 701/151, 701/206, 701/207, 701/213, 701/226, 701/214, 701/300
• US Class Current: 455/456.5
• CPC Class Codes: G01S 5/0284 Relative positioning
• CPC Class Codes: G01S 5/0289 of multiple transceivers, e.g. in ad hoc networks
• 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: G01S 5/10 Position of receiver fixed by co-ordinating a plurality of position lines defined by path-difference measurements , e.g. omega or decca systemsG01S5/12 takes precedence ; beacons and receivers cooperating therewith G01S1/306, G01S1/308
• 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

The present invention relates to a method of determining the location of a target. The method includes initializing a set of base stations to determine their location relative to each other. At the target, the time of arrival of at least one signal from each of the plurality of base stations Is measured. From this, the location of the target relative to the plurality of base stations may be directly calculated using a closed solution. In one embodiment, a time of arrival technique is used and in another embodiment a time difference of arrival technique is used. Preferably an ultra-wide band frequency is utilized.

Claims

1. A method of determining the location of a target, comprising:

initializing a plurality of base stations to determine their relative location to each other wherein, during initializing, a first base station of the plurality of base stations sends a spread-spectrum signal to a second base station and a third base station of the plurality of base stations to determine a distance between the first base station and the second base station and a distance between the first base station and the third base station and wherein the second base station sends a spread-spectrum signal to the third base station to determine a distance between the second base station and the third base station;

measuring, at the target, the time of arrival of at least one spread-spectrum signal from each of the plurality of base stations;

calculating directly the location of the target relative to the plurality of base stations, where the plurality of base stations is at least three when a time of arrival technique is used and wherein the plurality of base stations is at least four when a time difference of arrival technique is used.

2. The method of claim 1, wherein the target calculates its own position.

3. The method of claim 1, wherein each of the base stations is a mobile base station.

4. The method of claim 1, wherein the initializing step comprises using a time of arrival technique to determine the location of each base station.

5. The method of claim 1, further comprising initializing at least one of the plurality of base stations to determine the global geographic location of each of the plurality of base stations.

6. The method of claim 1, wherein the measuring and calculating steps are repeated at least 50 times a sec.

7. The method of claim 6, wherein the measuring and calculating steps are repeated at least 200 times a sec.

8. The method of claim 1, wherein the calculating step comprises using a time of arrival technique to calculate the location of the target.

9. The method of claim 1, wherein the calculating step comprises using a time difference of arrival technique to calculate the location of the target.

10. The method of claim 1, wherein the measuring step comprises transmitting a unique PN code from each base station.

11. The method of claim 1, wherein the measuring step comprises using a spread-spectrum signal with a chiprate between about 0.1 and about 10 Gbits/sec.

12. The method of claim 1, wherein the measuring step comprises using a DS-CDMA communication scheme.

13. The method of claim 1, wherein the measuring step comprises oversampling the received signal between about 0.3 and about 30 giga-samples/sec and wherein the measuring step comprises oversampling with a digital sampler or an analog-to-digital converter.

14. The method of claim 1 wherein the calculating step yields a location of the target with a resolution between about 0.01 and about 1.0 meter.

15. The method of claim 1, wherein the calculating step comprising performing a pseudo-inverse function on a matrix.

16. The method of claim 1 wherein the location is determined using a closed solution and the calculating step uses a non-iterative technique to calculate the location of the target.

17. A method of determining the location of a target, comprising:

initializing a plurality of base stations to determine their relative location to each other wherein, during initializing, a first base station of the plurality of base stations sends a spread-spectrum signal to a second base station and a third base station of the plurality of base stations to determine a distance between the first base station and the second base station and a distance between the first base station and the third base station and wherein the second base station sends a spread-spectrum signal to the third base station to determine a distance between the second base station and the third base station;

measuring, at the target, the time of arrival of at least one spread-spectrum signal from each of the plurality of base stations;

calculating directly the location of the target relative to the plurality of base stations, where the plurality of base stations is at least three when a time of arrival technique is used and wherein the plurality of base stations is at least four when a time difference of arrival technique is used wherein, for calculating the location of the target, the plurality of base stations creates a coordinate system with the first base station being an origin location, with the second base station being located on a first axis relative to the origin location and with the third base station being located on a second axis relative to the origin location.

18. The method of claim 17 wherein the coordinate system is set up on an ad hoc basis and is a local system entirely based upon relative distances between the plurality of base stations, the target or both.

19. The method of claim 17 wherein the location is determined using a closed solution and the calculating step uses a non-iterative technique to calculate the location of the target.

20. A method of determining the location of a target, comprising:

initializing a plurality of base stations to determine their relative location to each other wherein, during initializing, a first base station of the plurality of base stations sends a spread-spectrum signal to a second base station and a third base station of the plurality of base stations to determine a distance between the first base station and the second base station and a distance between the first base station and the third base station and wherein the second base station sends a spread-spectrum signal to the third base station to determine a distance between the second base station and the third base station;

measuring, at the target, the time of arrival of at least one spread-spectrum signal from each of the plurality of base stations;

calculating directly the location of the target relative to the plurality of base stations using a closed solution, where the plurality of base stations is at least three when a time of arrival technique is used and wherein the plurality of base stations is at least four when a time difference of arrival technique is used, wherein the calculating step uses a non-iterative technique to calculate the location of the target and wherein, for calculating the location of the target, the plurality of base stations creates a coordinate system with the first base station being an origin location, with the second base station being located on a first axis relative to the origin location and with the third base station being located on a second axis relative to the origin location and wherein the coordinate system is set up on an ad hoc basis and is a local system entirely based upon relative distances between the plurality of base stations, the target or both and wherein the plurality of base stations are non-line-of-sight relative to each other and wherein;

i. each of the base stations is a mobile base station;

ii. the measuring and calculating steps are repeated at least 200 times a sec;

iii. the calculating step yields a location of the target with a resolution between about 0.01 and about 1.0 meter.