Method for improved location determination accuracy using filtered and unfiltered ranging signals

• US 7,519,500 B2
• Filed: 03/17/2005
• Issued: 04/14/2009
• Est. Priority Date: 03/17/2005
• Status: Expired due to Fees

• Current Assignee: Qualcomm, Inc.
• Original Assignee: Qualcomm, Inc.
• Inventors: Seibert, Cristina A.
• Primary Examiner(s): Bui; Bryan
• Application Number:
  US11/083,852
• Publication Number:
  US 20060212259A1
• Time in Patent Office: 1,489 Days
• Field of Search: 702/150, 702/152, 702/153, 702/189, 702/190, 702/90, 702/94, 702/95, 702/69, 702/74, 455/456.1, 342/357.02, 342/357.09
• US Class Current: 702/150
• CPC Class Codes: G01S 19/42 Determining position
• CPC Class Codes: G01S 19/48 by combining or switching between position solutions derived from the satellite radio beacon positioning system and position solutions derived from a further system
• CPC Class Codes: G01S 5/0268 by deriving positions from different combinations of signals or of estimated positions in a single positioning system
• CPC Class Codes: G01S 5/14 Determining absolute distances from a plurality of spaced points of known location

Abstract

A method for selecting a location determination solution from a set of possible location determination solutions generated from filtered, unfiltered, and loosely filtered ranging signals. The solution is computed using a first algorithm and filtered ranging signals to obtain a filtered location determination solution. Additional location determination solutions are computed using a second algorithm with unfiltered ranging signals to obtain one or more unfiltered location determination solutions. Further additional location determination solutions may be computed using a third algorithm with loosely filtered ranging signals to obtain one or more loosely filtered location determination solutions. A final location determination solution is chosen from the set of filtered location determination solution, unfiltered location determination solutions, and loosely filtered location determination solutions via an optimizing metric, M.

Claims

1. A method for locating a user comprising:

using a first algorithm and a plurality of filtered ranging signals to compute a filtered location determination solution;

using a second algorithm and a plurality of unfiltered ranging signals to compute at least one unfiltered location determination solution; and

producing a final user location from the filtered location determination solution and the at least one unfiltered location determination solution using an optimizing metric.

2. The method of claim 1, wherein the optimizing metric is a root mean square (RMS) of residual errors associated with the plurality of filtered ranging signals and a root mean square (RMS) of residual errors associated with the plurality of unfiltered ranging signals.

3. The method of claim 1, wherein the optimizing metric is a normalized root mean square (NRMS) of residual errors associated with the plurality of filtered ranging signals and a normalized root mean square (NRMS) of residual errors associated with the plurality of unfiltered ranging signals.

4. The method of claim 1, wherein the first algorithm is Snaptrack PDM software.

5. The method of claim 1, wherein the second algorithm is Snaptrack PDM software.

6. The method of claim 1, wherein the second algorithm is an advanced forward link trilateration (AFLT) algorithm.

7. The method of claim 1, wherein the first algorithm is the same as the second algorithm.

8. The method of claim 1, wherein the plurality of filtered ranging signals are transmitted from at least one terrestrial source.

9. The method of claim 1, wherein the plurality of filtered ranging signals are transmitted from at least one satellite based source.

10. The method of claim 1, wherein the plurality of unfiltered ranging signals are transmitted from at least one terrestrial source.

11. The method of claim 1, wherein the plurality of unfiltered ranging signals are transmitted from at least one satellite based source.

12. A method for locating a user comprising:

using a first algorithm and a plurality of filtered ranging signals to compute a filtered location determination solution;

using a second algorithm and a plurality of unfiltered ranging signals to compute at least one unfiltered location determination solution;

using a third algorithm and a plurality of loosely filtered ranging signals to compute at least one loosely filtered location determination solution; and

producing a final user location from the filtered location determination solution, the at least one unfiltered location determination solution and the at least one loosely filtered location determination solution using an optimizing metric.

13. The method of claim 12, wherein the optimizing metric is a root mean square (RMS) of residual errors associated with the plurality of filtered ranging signals, a root mean square (RMS) of residual errors associated with the plurality of unfiltered ranging signals and a root mean square (RMS) of residual errors associated with the plurality of loosely filtered ranging signals.

14. The method of claim 12, wherein the optimizing metric is a normalized root mean square (NRMS) of residual errors associated with the plurality of filtered ranging signals, a normalized root mean square (NRMS) of residual errors associated with the plurality of unfiltered ranging signals and a normalized root mean square (RMS) of residual errors associated with the plurality of loosely filtered ranging signals.

15. The method of claim 12 where the third algorithm is the same as the first algorithm.

16. The method of claim 12 where the third algorithm is the same as the second algorithm.

17. Computer readable media embodying a program of instructions executable by a computer program to locate a user, the instructions to cause one or more machines to perform operations comprising:

using a first algorithm and a plurality of filtered ranging signals to compute a filtered location determination solution;

using a second algorithm and a plurality of unfiltered ranging signals to compute at least one unfiltered location determination solution; and

producing a final user location from the filtered location determination solution and the at least one unfiltered location determination solution using an optimizing metric.

18. The computer readable media of claim 17, wherein the optimizing metric is a root mean square (RMS) of residual errors associated with the plurality of filtered ranging signals and a root mean square (RMS) of residual errors associated with the plurality of unfiltered ranging signals.

19. The computer readable media of claim 17, wherein the metric optimizing is a normalized root mean square (NRMS) of residual errors associated with the plurality of filtered ranging signals and a normalized root mean square (NRMS) of residual errors associated with the plurality of unfiltered ranging signals.

20. Computer readable media embodying a program of instructions executable by a computer program to perform a method for locating a user, the instructions to cause one or more machines to perform operations comprising:

using a first algorithm and a plurality of filtered ranging signals to compute a filtered location determination solution;

using a second algorithm and a plurality of unfiltered ranging signals to compute at least one unfiltered location determination solution;

using a third algorithm and a plurality of loosely filtered ranging signals to compute at least one loosely filtered location determination solution; and

producing a final user location from the filtered location determination solution, the at least one unfiltered location determination solution and the at least one loosely filtered location determination solution using an optimizing metric.