Systems, methods and devices for satellite navigation reconciliation

• US 10,073,179 B2
• Filed: 03/24/2015
• Issued: 09/11/2018
• Est. Priority Date: 03/24/2015
• Status: Active Grant

• Current Assignee: Elwha LLC (Intellectual Ventures LLC)
• Original Assignee: Elwha LLC (Intellectual Ventures LLC)
• Inventors: Driscoll, Tom, Guerci, Joseph R., Hannigan, Russell J., Hyde, Roderick A., Ishikawa, Muriel Y., Kare, Jordin T., Myhrvold, Nathan P., Smith, David R., Tegreene, Clarence T., Urzhumov, Yaroslav A., Whitmer, Charles, Wood, Jr., Lowell L., Wood, Victoria Y. H.
• Primary Examiner(s): Gregory, Bernarr E
• Application Number:
  US14/667,402
• Publication Number:
  US 20160282473A1
• Time in Patent Office: 1,267 Days
• CPC Class Codes: G01S 19/396 Determining accuracy or reliability of position or pseudorange measurements

Abstract

A three-dimensional map of an environment with buildings is used to computationally predict locations and times of global navigation satellite system (GNSS) transmission quality. A global navigation satellite system (GNSS) receiver can reconcile received satellite transmissions with these predicted satellite transmissions. By comparing actual transmission quality with predicted transmission quality, a system can determine unmodeled obstructions, temporary obstructions, jamming, spoofing or other origins of interference with predicted transmission quality of a satellite in a GNSS.

Claims

1. A device for predicting satellite visibility, comprising:

storage configured to store a three-dimensional spatial map of one or more buildings within an environment and satellite ephemeris data; and

a processor configured to;

determine a position and a time within the three-dimensional spatial map;

determine a satellite position at the time based at least in part on the satellite ephemeris data;

simulate a signal transmission from the satellite to the position at the time based at least in part on the three-dimensional spatial map; and

compute a predicted transmission quality associated with the signal transmission at the position and the time; and

compare the predicted transmission quality with a measured transmission quality from the satellite obtained by a receiver at the position and the time to determine empirically measured blockage information,

wherein the position is outside each building of the three-dimensional spatial map.

2. The device of claim 1, wherein the processor is further configured to determine one or more positions for use with a secondary navigational system based on the empirically measured blockage information.

3. The device of claim 2, wherein the secondary navigational system is assisted global positioning system.

4. The device of claim 1, further comprising a peer to peer network interface.

5. The device of claim 4, wherein the measured transmission quality is received over the peer to peer network interface.

6. The device of claim 4, wherein to compare the predicted transmission quality against the measured transmission quality further comprises:

receive, from one or more secondary devices as peers, a set of measured transmission qualities obtained from a set of positions associated with a set of times; and

infer a blockage location within the three-dimensional spatial map of the environment based at least in part on the set of measured transmission qualities.

7. The device of claim 1, further comprising a network interface.

8. The device of claim 7, wherein the measured transmission quality at the position and the time is received over the network interface from a service.

9. The device of claim 8, wherein the processor is further configured to communicate with the service through an application program interface (API) to receive the measured transmission quality.

10. The device of claim 8, wherein to compare the predicted transmission quality against the measured transmission quality further comprises:

receive, from the service, a set of measured transmission qualities obtained from a set of positions associated with a set of times; and

infer a blockage location within the three-dimensional spatial map of the environment.

11. The device of claim 10, wherein the processor is further configured to add the blockage location to the three-dimensional spatial map of the environment.

12. The device of claim 10, wherein the processor is further configured to determine the blockage location is temporary based at least in part on the set of measured transmission qualities.

13. The device of claim 1, wherein the processor is further configured to:

determine a second satellite position of a second satellite at the time based at least in part on the satellite ephemeris data;

simulate a second signal transmission from the second satellite to the position at the time based at least in part on the three-dimensional spatial map;

compute a second predicted transmission quality associated with the second signal transmission at the position and the time; and

compare the second predicted transmission quality with a second measured transmission quality from the second satellite at the position and the time to form additional empirically measured blockage information; and

update the empirically measured blockage information based at least in part on the additional empirically measured blockage information.

14. The device of claim 13, wherein the processor is further configured to determine a number of satellites from a set of satellites, the number of satellites each having a signal transmission quality at or above a quality threshold at the position and the time.

15. The device of claim 14, wherein the processor is further configured to determine whether the number of satellites is at or above a navigation threshold.

16. The device of claim 15, wherein the navigation threshold is four signal transmissions.

17. The device of claim 14, wherein the processor is further configured to transmit information associated with the number of satellites.

18. The device of claim 1, wherein the three-dimensional spatial map comprises compositional data for at least one of the buildings.

19. The device of claim 1, wherein the processor is further configured to transmit information associated with the predicted transmission quality.

20. The device of claim 19, wherein the information comprises specification of a spacetime region neighboring the position and the time for which the predicted transmission quality is at or above a specified quality threshold.

21. The device of claim 19, wherein the information comprises specification of a spacetime region neighboring the position and the time for which the predicted transmission quality is below a specified quality threshold.

22. The device of claim 1, wherein the receiver is a local receiver.

23. A method for determining global navigation satellite system (GNSS) quality comprising:

determining a position and a time within a three-dimensional map of one or more buildings within an environment;

determining a satellite position at the time based at least in part on satellite ephemeris data for the satellite;

simulating a signal transmission from the satellite to the position at the time; and

determining a predicted transmission quality associated with the signal transmission; and

obtaining from a receiver a measurement of an actual signal quality from the satellite to the receiver at the position and time; and

determining if the measured transmission quality is inconsistent with the predicted transmission quality at the position and time.

24. The method of claim 23, further comprising transmitting information associated with the satellite and the predicted transmission quality to a client device.

25. The method of claim 23, further comprising determining a set of predicted transmission qualities of a set of satellites in the GNSS based at least in part on the three-dimensional time map;

and

determining a predicted positional quality of the GNSS at the position and the time based at least in part on the set of predicted transmission qualities.

26. The method of claim 25, further comprising determining a spacetime location is a candidate for supplementing the GNSS with a secondary navigation system based at least in part on the set of predicted transmission qualities.

27. The method of claim 23, wherein determining that a measured transmission quality is inconsistent with the predicted transmission quality further comprises determining that a noise level of the measured transmission quality is inconsistent with the predicted transmission quality.

28. The method of claim 27, wherein determining the noise level of the measured transmission quality is inconsistent with the predicted transmission quality further comprises determining the noise level is consistent with jamming.

29. The method of claim 23, wherein determining that a measured transmission quality is inconsistent with the predicted transmission quality further comprises determining that a difference between the measured transmission quality and the predicted transmission quality is at or above a differential threshold.

30. The method of claim 29, wherein determining the difference between the measured transmission quality and the predicted transmission quality is at or above the differential threshold further comprises determining the measured signal transmission is consistent with spoofing.

31. The method of claim 23, wherein determining that a measured transmission quality is inconsistent with the predicted transmission quality further comprises determining that the measured transmission quality is lower than predicted.

32. The method of claim 31, wherein determining the measured transmission quality is lower than predicted further comprises determining the measured transmission quality is consistent with a temporary obstruction.

33. The method of claim 31, wherein determining the measured transmission quality is lower than predicted further comprises determining the measured transmission quality is consistent with an obstruction missing from the three-dimensional time map.

34. The method of claim 33, further comprising adding the obstruction to the three-dimensional time map.

35. The method of claim 23, wherein simulating the signal transmission from the satellite to the position at the time further comprises simulating transmissions from a set of satellites to one or more spacetime locations within a spacetime navigation route.

36. The method of claim 35, wherein determining the predicted transmission quality associated with the signal transmission further comprises determining a subset of satellites from the set of satellites are able to provide predicted transmission qualities that are at or above a quality threshold at a given spacetime location within the spacetime navigation route.

37. The method of claim 36, wherein determining which satellites from the set of satellites are able to provide the predicted transmission qualities that are at or above the quality threshold at the given spacetime location further comprises:

determining a set of segments of the spacetime navigation route that are below a threshold number of satellites providing the predicted transmission qualities above the quality threshold based on the three-dimensional time map of the environment and the satellite ephemeris data; and

predicting degraded functionality of the GNSS along the set of segments.

38. The method of claim 37, wherein predicting degraded functionality of the GNSS along the set of segments further comprises determining a predicted duration of time of degraded functionality for a segment from the set of segments.

39. The method of claim 36, wherein determining the predicted transmission quality associated with the signal transmission further comprises determining the subset of satellites is below a navigation threshold of a number of satellites.

40. The method of claim 39, wherein determining the subset of satellites is below the navigation threshold of the number of satellites further comprises determining a predicted duration of time that the navigation threshold is not met.

41. A method comprising:

receiving from a receiver a measured transmission quality of a signal transmission of a satellite at a spacetime position;

predicting using a computer system a predicted transmission quality from the satellite to the spacetime position based on a three-dimensional spatial map of an environment and satellite ephemeris data; and

determining using the computer system that interference exists based at least in part on the measured transmission quality and the predicted transmission quality.

42. The method of claim 41, further comprising predicting a predicted location based services quality.

43. The method of claim 41, wherein predicting a predicted transmission quality further comprises predicting a set of predicted location based services qualities along a first route and a second route;

and

wherein the method further comprises computing a recommendation of the first route or the second route based at least in part on the predicted location based services qualities.

44. The method of claim 41, wherein determining the interference exists further comprises:

determining that a set of measurements at a subset of a set of spacetime locations have a set of transmission qualities lower than indicated in associated predicted transmission qualities; and

determining a locus of measurements that converge to indicate an unmodeled obstruction.