LOCALLY MEASURED MOVEMENT SMOOTHING OF GNSS POSITION FIXES

• US 20140375493A1
• Filed: 05/02/2014
• Published: 12/25/2014
• Est. Priority Date: 12/28/2012
• Status: Active Grant

• Current Assignee: Trimble Inc.
• Original Assignee: Trimble Navigation Limited (Trimble Inc.)
• Inventors: Weisenburger, Shawn D., Rudow, Richard, Talbot, Nicholas C., Loomis, Peter Van Wyck, Janky, James M.
• Granted Patent: US 9,488,736 B2
• Time in Patent Office: Days
• US Class Current: 342/357.3
• CPC Class Codes: G01S 19/45 by combining measurements of signals from the satellite radio beacon positioning system with a supplementary measurement
• CPC Class Codes: G01S 19/47 the supplementary measurement being an inertial measurement, e.g. tightly coupled inertial
• CPC Class Codes: G01S 19/485 whereby the further system is an optical system or imaging system
• CPC Class Codes: G06T 2207/10004 Still image; Photographic image
• CPC Class Codes: G06T 2207/20076 Probabilistic image processing
• CPC Class Codes: G06T 7/277 involving stochastic approaches, e.g. using Kalman filters

Abstract

A method of improving position determination of a device using locally measured movement. A first position fix of a Global Navigation Satellite System (GNSS) receiver system of a device is accessed. A second position fix of the GNSS receiver system is accessed at a time subsequent to the first position fix. Locally measured device movement information is obtained from at least one sensor, that is in a known physical relationship to the device, for a time period after the first position fix and no later than the second position fix, wherein the at least one sensor comprises an image capture device. The quality of measurement of the second position fix is improved by disciplining the second position fix based on the locally measured device movement information.

Claims

1. A method of improving position determination of a device using locally measured movement, said method comprising:

accessing a first position fix of a Global Navigation Satellite System (GNSS) receiver system of a device;

accessing a second position fix of said GNSS receiver system at a subsequent time to said first position fix;

obtaining locally measured device movement information, from at least one sensor that is in a known physical relationship to said device, for a time period after said first position fix and no later than said second position fix, wherein said at least one sensor comprises an image capture device; and

improving a quality of measurement of said second position fix by disciplining said second position fix based on said locally measured device movement information.

2. The method of claim 1 wherein said at least one sensor further comprises at least one accelerometer which is not a component of an inertial measurement unit (IMU).

3. The method of claim 2 further comprising:

determining if the locally measured device movement information received from said accelerometer has become an unreliable metric for determining the movement of said device; and

responsive to said locally measured device movement information received from said accelerometer being determined to be unreliable for determining the movement of said device, using the locally measured device movement information received from said image capture device for disciplining said second position fix.

4. The method of claim 1 wherein said GNSS receiver system comprises a plurality of sub-systems and wherein at least one of said plurality of sub-systems is accessible by a processor.

5. The method of claim 4 wherein said accessing, said obtaining, and said improving are performed by one or more hardware processors located in said GNSS receiver system.

6. The method of claim 1 wherein said GNSS receiver system comprises a GNSS chipset.

7. The method of claim 6 wherein said accessing, said obtaining, and said improving are performed by one or more hardware processors located in said device and outside of said GNSS chipset.

8. The method of claim 6 wherein said accessing, said obtaining, and said improving are performed by one or more hardware processors located in said GNSS chipset.

9. The method of claim 1 further comprising:

determining that said second position fix comprises an erroneous position fix.

10. The method of claim 9 wherein said improving said quality of measurement of said second position fix further comprises:

using a Kalman filter to determine that said second position fix comprises an outlier value.

11. The method of claim 10 further comprising:

discarding said second position fix based on said locally measured device movement information.

12. The method of claim 10 further comprising:

using locally measured device movement information received from at least said image capture device to derive a third position fix.

13. The method of claim 1 further comprising:

determining an average value of locally measured device movement information received from said image capture device to indicate the movement of said device.

14. The method of claim 13 wherein said average value comprises a weighted average of locally measured device movement information received from said image capture device.

15. The method of claim 1 further comprising:

capturing audio information using a microphone coupled with said device; and

converting said audio information using an analog-to-digital converter (ADC).

16. The method of claim 1, wherein said accessing a first position fix of a Global Navigation Satellite System (GNSS) receiver system of a device, wherein said device is a mobile device:

accessing said first position fix of said GNSS receiver system of said device, wherein said device is a mobile device.

17. The method of claim 1, wherein said accessing a first position fix of a Global Navigation Satellite System (GNSS) receiver system of a device, wherein said device is a mobile device:

accessing said first position fix of said GNSS receiver system of said device, wherein said device is disposed as a portion of an unmanned aerial vehicle.

18. A non-transitory computer readable storage medium having computer readable instructions stored thereon for causing a computer system to perform a method of improving position determination of a device using locally measured movement, said method comprising:

accessing a first position fix of a Global Navigation Satellite System (GNSS) receiver system of a device;

accessing a second position fix of said GNSS receiver system at a subsequent time to said first position fix;

obtaining locally measured device movement information, from at least one sensor that is in a known physical relationship to said device, for a time period after said first position fix and no later than said second position fix, wherein said at least one sensor comprises an image capture device; and

improving a quality of measurement of said second position fix by disciplining said second position fix based on said locally measured device movement information.

19. The non-transitory computer readable storage medium of claim 18 wherein said at least one sensor further comprises at least one accelerometer which is not a component of an inertial measurement unit (IMU).

20. The non-transitory computer readable storage medium of claim 19, wherein said method further comprises:

determining if the locally measured device movement information received from said accelerometer has become an unreliable metric for determining the movement of said device; and

responsive to said locally measured device movement information received from said accelerometer being determined to be unreliable for determining the movement of said device, using the locally measured device movement information received from said image capture device for disciplining said second position fix.

21. The non-transitory computer readable storage medium of claim 18 wherein said GNSS receiver system comprises a plurality of sub-systems and wherein at least one of said plurality of sub-systems is accessible by a processor.

22. The non-transitory computer readable storage medium of claim 21 wherein said accessing, said obtaining, and said improving are performed by one or more hardware processors located in said GNSS receiver system.

23. The non-transitory computer readable storage medium of claim 18 wherein said GNSS receiver system comprises a GNSS chipset.

24. The non-transitory computer readable storage medium of claim 23 wherein said accessing, said obtaining, and said improving are performed by one or more hardware processors located in said device and outside of said GNSS chipset.

25. The non-transitory computer readable storage medium of claim 23 wherein said accessing, said obtaining, and said improving are performed by one or more hardware processors located in said GNSS chipset.

26. The non-transitory computer readable storage medium of claim 18 wherein said improving said quality of measurement of said second position fix further comprises:

determining that said second position fix comprises an erroneous position fix.

27. The non-transitory computer readable storage medium of claim 26 wherein said improving said quality of measurement of said second position fix further comprises:

using a Kalman filter to determine that said second position fix comprises an outlier value.

28. The non-transitory computer readable storage medium of claim 27 further comprising:

discarding said second position fix based on said locally measured device movement information.

29. The non-transitory computer readable storage medium of claim 27 further comprising:

using locally measured device movement information received from at least said image capture device to derive a third position fix.

30. The non-transitory computer readable storage medium of claim 18 further comprising:

determining an average value of locally measured device movement information received from said image capture device to indicate the movement of said device.

31. The non-transitory computer readable storage medium of claim 30 wherein said average value comprises a weighted average of locally measured device movement information received from said image capture device.

32. The non-transitory computer readable storage medium of claim 18 wherein said method further comprises:

capturing audio information using a microphone coupled with said device; and

converting said audio information using an analog-to-digital converter (ADC).

33. A system for improving position determination of a device using locally measured movement, said system comprising:

a locally measured movement (LMM) smoothing logic component implemented by a processor for accessing a first position fix of a Global Navigation Satellite System (GNSS) receiver system of a device and for accessing a second position fix of said GNSS receiver system at a subsequent time to said first position fix;

an image capture device for obtaining locally measured device movement information from at least one sensor, that is in a known physical relationship to said device, for a time period after said first position fix and no later than said second position fix; and

wherein said LMM smoothing logic is further configured for improving a quality of measurement of said second position fix by disciplining said second position fix based on said locally measured device movement information.

34. The system of claim 33 further comprising:

at least one accelerometer, which is not a component of an inertial measurement unit (IMU), that is in a known physical relationship to said device, for obtaining locally measured device movement information for a time period after said first position fix and no later than said second position fix.

35. The system of claim 34 further comprising:

a dual-sensor averaging logic implemented by said processor for determining an average value of locally measured device movement information received from said accelerometer and said image capture device to indicate the movement of said device.

36. The system of claim 35 wherein said average value comprises a weighted average of locally measured device movement information received from said accelerometer and said image capture device.

37. The system of claim 34 further comprising:

a dual-sensor averaging logic implemented by said processor for determining if the locally measured device movement information received from said accelerometer has become an unreliable metric for determining the movement of said device and for using the locally measured device movement information received from said image capture device for disciplining said second position fix in response to determining information received from said accelerometer is unreliable for determining the movement of said device.

38. The system of claim 33 further comprising:

a microphone configured for capturing audio information; and

an analog-to-digital converter (ADC) coupled with microphone and configured to convert the audio information to a digital format.

39. The system of claim 33 wherein said GNSS receiver system comprises a GNSS chipset.

40. The system of claim 33 wherein said GNSS receiver system comprises a plurality of sub-systems and wherein at least one of said plurality of sub-systems is accessible by a processor.

41. The system of claim 40 wherein said accessing, said obtaining, and said improving are performed by one or more hardware processors located in said GNSS receiver system.

42. The system of claim 33 wherein said LMM smoothing logic is configured to determine that said second position fix comprises an erroneous position fix.

43. The system of claim 42 wherein said accessing, said obtaining, and said improving are performed by one or more hardware processors located in said device and outside of said GNSS chipset.

44. The system of claim 42 wherein said accessing, said obtaining, and said improving are performed by one or more hardware processors located in said GNSS chipset.

45. The system of claim 42 wherein said LMM smoothing logic comprises a Kalman filter configured to determine that said second position fix comprises an outlier value.

46. The system of claim 45 wherein said LMM smoothing logic is further configured to discard said second position fix based on said locally measured device movement information.

47. The system of claim 45 wherein said LMM smoothing logic is further configured to use locally measured device movement information received from at least said image capture device.

48. The system of claim 33, wherein said device comprises a mobile device.

49. The system of claim 33 wherein said device is a portion of an unmanned aerial vehicle.