Method and system for extensible position location

• US 7,602,339 B2
• Filed: 07/03/2007
• Issued: 10/13/2009
• Est. Priority Date: 04/12/2004
• Status: Active Grant

• Current Assignee: Plus Location Systems Pty. Limited
• Original Assignee: Time Domain Corporation (Humatics Corporation)
• Inventors: O'Hanian, S. Scott, Einhorn, W. Michael II, Fullerton, Larry W., Roberts, Mark D., Loum, Kelly, Dodoukh, Irina
• Primary Examiner(s): Mull; Fred H.
• Application Number:
  US11/822,239
• Publication Number:
  US 20080158062A1
• Time in Patent Office: 833 Days
• Field of Search: 342/458, 342463-465, 455/456.1
• US Class Current: 342/463
• CPC Class Codes: G01S 5/0289 of multiple transceivers, e.g. in ad hoc networks

Abstract

A method and system for extensible positioning that uses a primary reference node at a known first position and a secondary reference node at a second position, where a range is measured between the secondary reference node and the primary reference node. The second position is determined based upon the first position and the measured range. A second range is measured between the secondary reference node and a non-fixed node. A third position corresponding to the non-fixed node is determined based upon the second position and the second range.

Claims

1. A method for determining a position of an ultra wideband (UWB) radio, comprising:

determining using a processor a plurality of positions corresponding to a plurality of reference UWB radios;

determining using a processor a plurality of confidence metrics corresponding to said plurality of positions;

selecting using a processor a plurality of acceptable positions based upon said plurality of confidence metrics and an acceptance criteria; and

determining using a processor said position of said UWB radio based upon said plurality of acceptable positions, said processor outputting to an interface said position of said UWB radio.

2. The method of claim 1, wherein said acceptance criteria provides a highest possible confidence level of said position of said UWB radio.

3. The method of claim 1, wherein at least one of said plurality of positions is determined based upon a UWB signal transmission.

4. The method of claim 3, wherein said UWB signal transmission is one of a one-way signal transmission or a round-trip signal transmission.

5. The method of claim 1, wherein at least one of said plurality of reference UWB radios is non-fixed.

6. The method of claim 1, wherein said UWB radio is capable of transmitting UWB signals and said UWB radio is not capable of receiving UWB signals.

7. The method of claim 1, wherein each of said plurality of confidence metrics comprises at least one of a range measurement quality metric, a standard deviation, a measurement age metric, an error region metric, a signal quality metric, an RF environment metric, or a ranging geometry metric.

8. The method of claim 7, wherein said ranging geometry metric comprises at least one of an angle acuteness metric or a geometric dilution of precision metric.

9. The method of claim 1, wherein the non-existence of a direct path between said UWB radio and at least one of said plurality of reference UWB radios is identified.

10. The method of claim 1, wherein a confidence level of said position indicates a requirement for one or more additional reference UWB radios to achieve an acceptable said confidence level.

11. The method of claim 1, wherein said UWB radio is a secondary reference UWB radio.

12. The method of claim 1, further comprising:

filtering ranging noise prior to determining at least one position.

13. The method of claim 1, further comprising:

positioning said plurality of reference UWB radios at locations intended to provide acceptable position determination accuracy over a coverage area.

14. The method of claim 1, further comprising:

positioning said plurality of reference UWB radios such that said UWB radio is always within at least a desired distance from a closest reference UWB radio of said plurality of reference UWB radios.

15. The method of claim 1, wherein said acceptance criteria comprises at least one of a acceptability threshold or a decision tree.

16. The method of claim 1, wherein said acceptance criteria comprises at least one of a threshold, a decision tree, a work load, a number of times an error region has compounded, a line-of-sight characteristic, a speed, a direction, an elevation, a speed in change of speed, a speed in change of direction, or a speed in change of elevation.

17. The method of claim 1, wherein at least one of said plurality of reference UWB radios comprises a primary reference UWB radio.

18. The method of claim 1, wherein at least one of said plurality of reference UWB radios is positioned by one of a robot, a soldier, a firefighter, a police officer, or an emergency responder.

19. A system for determining a position of an ultra wideband (UWB) radio, comprising:

a plurality of reference UWB radios corresponding to a plurality of positions; and

at least one processor that determines a plurality of confidence metrics corresponding to said plurality of positions, selects a plurality of acceptable positions from said plurality of positions based upon said plurality of confidence metrics and an acceptance criteria, determines said position of said UWB radio based upon said plurality of acceptable positions, and outputs said position of said UWB radio to an interface.

20. A method for determining a position of an ultra wideband (UWB) radio, comprising:

determining using a processor a plurality of position confidence metrics corresponding to a plurality of reference UWB radio positions;

selecting using a processor a plurality of acceptable reference UWB radio positions from said plurality of UWB radio positions based upon said plurality of position confidence metrics and an acceptance criteria; and

determining using a processor said position of said UWB radio based upon said plurality of acceptable reference radio positions, said processor outputting to an interface said position of said UWB radio.