METHOD AND DEVICE FOR DETERMINING A LOCATION OF A COMMUNICATIONS DEVICE

• US 20080146246A1
• Filed: 12/19/2006
• Published: 06/19/2008
• Est. Priority Date: 12/19/2006
• Status: Active Grant

• Current Assignee: The Boeing Co.
• Original Assignee: The Boeing Co.
• Inventors: Bornholdt, James M.
• Granted Patent: US 7,783,301 B2
• Time in Patent Office: Days
• US Class Current: 455/456.1
• CPC Class Codes: G01S 5/0244 Accuracy or reliability of position solution or of measurements contributing thereto
• CPC Class Codes: G01S 5/0273 using multipath or indirect path propagation signals in position determination

Abstract

A method to determine a location of a communications device may include measuring a time of arrival for each pulse received at a receiver. The method may also include generating a set of possible hypothetical matches between each received pulse and a transmission path between a transmitter and the receiver, wherein the communications device being located is one of the transmitter and the receiver. The method may further include estimating the location of the communications device using the set of hypothetical matches.

Claims

1. A method to determine a location of a communications device, comprising:

measuring a time of arrival for each pulse received at a receiver;

generating a set of hypothetical matches between each received pulse and a transmission path between a transmitter and the receiver, wherein the communications device being located is one of the transmitter and the receiver; and

estimating the location of the communications device using the set of hypothetical matches.

2. The method of claim 1, wherein estimating the location of the communications device comprises determining a locus of possible communications device locations for each pulse using the hypothetical matches.

3. The method of claim 2, further comprising determining an estimated location of the communications device as an intersection of possible communications device location loci for each set of hypothetical matches for each pulse.

4. The method of claim 3, further comprising:

determining an error in the estimated location of the communications device for each set of hypothetical match for each pulse received; and

selecting a best location estimate as the estimated location with a lowest error.

5. The method of claim 4, wherein determining the error in the estimated location, comprises:

approximating each locus of possible communications device locations as a set of discrete points;

looping each discrete point over other loci for each possible communications device location;

determining a residual error for each discrete point in loci for each possible communications device location;

determining a sum of squares of residual error for each discrete point; and

selecting the estimated communications device location as a discrete point with a minimum sum of residual errors.

6. The method of claim 2, further comprising:

defining a hypothetical transmit time for each pulse in response to the transmit time for each pulse being unknown;

generating an additional set of hypothetical matches for each hypothetical transmit time and transmission path;

determining a locus of possible communications device locations using each set of hypothetical transmission paths for each pulse and each hypothetical transmit time; and

determining an estimated location of the communications device as an intersection of possible communications device location loci for each set of hypothetical matches for each pulse and for each hypothetical transmit time.

7. The method of claim 6, further comprising:

determining an error in the estimated location of the communications device for each pulse received and hypothetical transmit time; and

selecting a best location estimate as the estimated location with a lowest error.

8. The method of claim 2, wherein determining the locus of possible communications device locations comprises defining a circle centered at a first scattering center from the communications device in each hypothetical match including a NLOS transmission path, if the communications device to be located is the transmitter.

9. The method of claim 2, wherein determining the locus of possible communications device locations comprises defining a circle centered at a last scattering center before the communications device in each hypothetical match including a NLOS transmission path, if the communications device to be located is the receiver.

10. The method of claim 1, further comprising forming a set of possible transmission paths from the transmitter to the receiver.

11. The method of claim 10, wherein forming the set of possible transmission paths comprises:

forming a direct transmission path from the transmitter to the receiver;

forming all combinations for bounces from any scattering centers; and

determining all permutations of possible transmission paths grouped into sets of elements based on a number of pulses received by the receiver.

12. The method of claim 11, further comprising associating each set of elements with a unique received pulse for each permutation.

13. The method of claim 12, further comprising creating each hypothetical match associated with a unique pulse for each transmit time or hypothetical transmit time.

14. The method of claim 1, further comprising determining a location of any scattering centers.

15. The method of claim 14, further comprising:

estimating a location of the receiver if the communications device to be located is the transmitter; and

estimating a location of the transmitter if the communications device to be located is the receiver.

16. A method to determine a location of a communications device, comprising:

measuring a time of arrival for each pulse received at a receiver;

generating a set of possible hypothetical matches by matching each pulse received by the receiver to a possible transmission path of the received pulse between a transmitter and the receiver, wherein the communications device being located is one of the transmitter and the receiver;

determining a locus of possible communications device locations using each set of hypothetical matches for each pulse; and

determining an estimated location of the communications device as an intersection of possible communications device location loci for each set of hypothetical matches for each pulse.

17. The method of claim 16, further comprising:

determining an error in the estimated location of the communications device for each set of hypothetical matches for each pulse received; and

selecting a best location estimate as the estimated location with a lowest error.

18. The method of claim 16, further comprising:

defining a hypothetical transmit time for each pulse in response to the transmit time for each pulse being unknown;

generating an additional set of hypothetical matches for each hypothetical transmit time, pulse and transmission path;

determining a locus of possible communications device locations using each set of hypothetical matches for each pulse and each hypothetical transmit time; and

determining an estimated location of the communications device as an intersection of possible communications device location loci for each set of hypothetical matches for each pulse and for each hypothetical transmit time.

19. The method of claim 18, wherein determining the locus of possible communications device locations comprises defining a circle centered at a first scattering center from the communications device in each hypothetical match including a NLOS transmission path if the communications device to be located is the transmitter.

20. The method of claim 18, wherein determining the locus of possible communications device locations comprises defining a circle centered around a last scattering center before the communications device in each hypothetical match including a NLOS transmission path if the communications device to be located is the receiver.

21. A device to determine a location of a communications device, comprising:

a processor; and

a location determination module including a hypothetical match evaluation element operable on the processor to evaluate a match between each received pulse and a possible transmission path of the pulse to determine a location of the communications device.

22. The device of claim 21, further comprising:

means for measuring a time of arrival for each pulse received at a receiver;

means for generating a set of hypothetical matches between each pulse received and a possible hypothetical transmission path of the pulse from a transmitter to the receiver; and

means for estimating the location of the communications device using the set of hypothetical matches for each pulse.

23. The device of claim 22, wherein the means for estimating the location of the communications device comprises means for determining a locus of possible communications device locations using the hypothetical matches for each pulse.

24. The device of claim 23, further comprising means for determining an estimated location of the communications device as an intersection of possible communications device location loci for each set of hypothetical transmission paths for each pulse.

25. The device of claim 23, further comprising:

means for defining a hypothetical transmit time for each pulse in response to the transmit time for each pulse being unknown;

means for generating an additional set of hypothetical matches for each hypothetical transmit time, pulse and transmission path;

means for determining a locus of possible communications device locations using the hypothetical matches for each pulse and each hypothetical transmit time; and

means for determining an estimated location of the communications device as an intersection of possible communications device location loci for the set of hypothetical matches for each pulse and for each hypothetical transmit time.

26. The device of claim 25, further comprising:

means for determining an error in the estimated location of the communications device for each set hypothetical matches and received pulses; and

means for selecting a best location estimate as the estimated location with a lowest error.

27. The device of claim 21, wherein the communications device comprises the device to determine the location of the communications device.

28. A computer program product to determine a location of a communications device, the computer program product comprising:

a computer usable medium having computer usable program code embodied therein, the computer usable medium comprising;

computer usable program code configured to measure a time of arrival for each pulse received at a receiver;

computer usable program code configured to generate a set of hypothetical matches between each received pulse and a transmission path between a transmitter and the receiver, wherein the communications device being located is one of the transmitter and the receiver; and

computer usable program code configured to estimate the location of the communications device using the set of hypothetical matches.

29. The computer program product of claim 28, further comprising computer usable program code configured to determine a locus of possible communications device locations for each pulse using the hypothetical matches.

30. The computer program product of claim 29, further comprising computer usable program code configured to determining an estimated location of the communications device as an intersection of possible communications device location loci for each set of hypothetical matches for each pulse.

31. The computer program product of claim 30, further comprising:

computer usable program code configured to determine an error in the estimated location of the communications device for each set of hypothetical match for each pulse received; and

computer usable program code configured to select a best location estimate as the estimated location with a lowest error.

32. The computer program product of claim 30, further comprising:

computer usable program code configured to define a hypothetical transmit time for each pulse in response to the transmit time for each pulse being unknown;

computer usable program code configured to generate an additional set of hypothetical matches for each hypothetical transmit time and path;

computer usable program code configured to determine a locus of possible communications device locations using each set of hypothetical matches for each pulse and each hypothetical transmit time; and

computer usable program code configured to determine an estimated location of the communications device as an intersection of possible communications device location loci for each set of hypothetical matches for each pulse and for each hypothetical transmit time.

33. A vehicle, comprising:

a device to determine a location of the vehicle, wherein the device includes;

a processor; and

a location determination module including a hypothetical match evaluation element operable on the processor to evaluate a match between each received pulse and a possible transmission path of the pulse to determine a location of the vehicle.

34. The vehicle of claim 33, further comprising:

means for measuring a time of arrival for each pulse received at a receiver;

means for generating a set of hypothetical matches between each pulse received and a possible hypothetical transmission path of the pulse from a transmitter to the receiver; and

means for estimating the location of the vehicle using the set of hypothetical matches for each pulse.

35. The vehicle of claim 34, wherein the means for estimating the location of the communications device comprises means for determining a locus of possible communications device locations using the hypothetical matches for each pulse.