DOPPLER AIDED INERTIAL NAVIGATION

• US 20120086606A1
• Filed: 10/07/2011
• Published: 04/12/2012
• Est. Priority Date: 10/08/2010
• Status: Active Grant

• Current Assignee: MDSP Technologies LLC
• Original Assignee: TeleCommunication Systems Inc (Comtech Telecommunications Corporation)
• Inventors: Mathews, Michael B., MacDoran, Peter F.
• Granted Patent: US 9,239,376 B2
• Time in Patent Office: Days
• US Class Current: 342/461
• CPC Class Codes: G01C 21/1654 with electromagnetic compass
• CPC Class Codes: G01S 11/10 using Doppler effect
• CPC Class Codes: G01S 5/0263 by combining or switching between positions derived from two or more separate positioning systems

Abstract

Doppler Aided Inertial Navigation (DAIN) facilitates the determination of position, velocity and direction of mobile devices operating in highly obstructed GPS/GNSS environments. Delivering high precision, high resolution positioning information using signals of opportunity, the present invention measures the Doppler shift of a moving device using a variety of signals combined with inertial accelerometers and environmental sensors to deliver an autonomous positioning and navigation capability that does not require external infrastructure or a priori knowledge of signal sources.

Claims

1. A system for providing physical state information of a mobile device, comprising

a receiver associated with the mobile device, the receiver configured to transform no more than two intercepted radio frequency emissions external to the mobile device into Doppler frequency observables from which speed can be determined;

a plurality of inertial sensors associated with the mobile device, the sensors having at least one linear accelerometer configured to produce acceleration observables; and

a physical state estimator configured to process the Doppler frequency observables and acceleration observables to determine at least one member of the physical state of the mobile device, wherein the speed extracted from the Doppler frequency observables is used to constrain inertial drift error.

2. The system of claim 1, wherein speed is determined from the Doppler frequency observables using a narrowband signal detector configured to optimize precision and sensitivity for motion dynamics of the system.

3. The system of claim 1, wherein the Doppler frequency observables are produced from the no more than two intercepted radio frequency emissions using spectral compression utilizing a non-linear operation to produce a set of observables suitable for physical state estimation by the physical state estimator.

4. The system of claim 3, wherein the set of observables produced using spectral compression includes at least one of physical characteristics in the form of amplitude, phase and temporal derivatives of the no more than two intercepted radio frequency emissions.

5. The system of claim 1, wherein the plurality of inertial sensors have at least one rotational accelerometer configured to produce angular acceleration observables.

6. The system of claim 1, further comprising at least one environmental sensor associated with the mobile device configured to provide information related to the environment in which the mobile device is located.

7. The system of claim 6, wherein the at least one environmental sensor associated with the mobile device provides at least one of magnetic compass or barometric pressure.

8. The system of claim 1, further comprising at least one positioning sensor associated with the mobile device configured to provide information related to the location of the mobile device.

9. The system of claim 8, wherein the at least one positioning sensor associated with the mobile device utilizes at least one of a GPS/GNSS or assisted GPS/GNSS signals, Wi-Fi Received Signal Strength Indication (RSSI), Cell ID, Bluetooth beacon or RFID tag.

10. The system of claim 1, further comprising a map cache providing map information relative to the current physical location of the mobile device, wherein the map information is used to compare the at least one member of the physical state of the mobile device with the map information to update the at least one member of the physical state of the mobile device.

11. The system of claim 1, wherein the mobile device is carried on a person and the physical state estimator is configured to estimate the step-size and step-rate using the Doppler frequency observables and acceleration observables.

12. The system of claim 11, wherein the step-size and step-rate are used by the physical state estimator to update the at least one member of the physical state of the mobile device.

13. The system of claim 1, wherein at least one of the two intercepted radio frequency emissions external to the mobile device is from a stationary source.

14. A system for providing physical state information relative to a mobile device in a GPS/GNSS obstructed environment, comprising

a receiver associated with the mobile device, the receiver configured to transform at least one intercepted non-GPS/GNSS emission external to the mobile device into Doppler frequency observables from which speed can be determined;

a plurality of inertial sensors associated with the mobile device, the sensors having at least one linear accelerometer configured to produce acceleration observables; and

a physical state estimator configured to process the Doppler frequency observables and acceleration observables to determine at least one member of the physical state of the mobile device, wherein the speed extracted from the Doppler frequency observables is used to constrain inertial drift error.

15. The system of claim 14, wherein speed is determined from the Doppler frequency observables using a narrowband signal detector configured to optimize precision and sensitivity for motion dynamics of the system.

16. The system of claim 14, wherein the Doppler frequency observables are produced from at least one intercepted non-GPS/GNSS emission using spectral compression utilizing a non-linear operation to produce a set of observables suitable for physical state estimation by the physical state estimator.

17. The system of claim 16, wherein the set of observables produced using spectral compression includes at least one of physical characteristics in the form of amplitude, phase and temporal derivatives of the at least one intercepted non-GPS/GNSS emission.

18. The system of claim 16, wherein the plurality of inertial sensors have at least one rotational accelerometer configured to produce angular acceleration observables.

19. The system of claim 16, further comprising at least one environmental sensor associated with the mobile device configured to provide information related to the environment in which the mobile device is located.

20. The system of claim 19, wherein the at least one environmental sensor associated with the mobile device provides at least one of magnetic compass or barometric pressure.

21. The system of claim 16, further comprising at least one positioning sensor associated with the mobile device configured to provide information related to the location of the mobile device.

22. The system of claim 21, wherein the at least one positioning sensor associated with the mobile device utilizes at least one of a Wi-Fi Received Signal Strength Indication (RSSI), Cell ID, Bluetooth beacon or RFID tag.

23. The system of claim 16, further comprising a map cache providing map information relative to the current physical location of the mobile device, wherein the map information is used to compare the at least one member of the physical state of the inertial sensors with the map information relative to the current physical location of the mobile device.

24. The system of claim 16, wherein the mobile device is carried on a person and the system further comprises a step analyzer used to estimate step-size and step-rate as a function of the Doppler frequency observables and acceleration observables.

25. The system of claim 16, wherein the at least one intercepted non-GPS/GNSS emission is from a stationary source.

26. A system for determining the speed of a mobile device in a multipath environment, comprising

a receiver associated with the mobile device configured to intercept at least one radio frequency emission traveling along a plurality of reflected paths from an emitter to the receiver;

and

a signal processor configured to transform the reflected radio frequency emission into Doppler frequency observables using Doppler broadening detection, wherein the speed of the mobile device is determined from the Doppler frequency observables.

29. The system of claim 26, wherein the at least one intercepted radio frequency emission is from a stationary source.

30. The system of claim 26, wherein the at least one intercepted radio frequency emission is a Wi-Fi, cellular, Bluetooth, satellite radio or digital television signal.

31. The system of claim 26, wherein the signal processor is configured to transform the reflected radio frequency emission into Doppler frequency observables using Doppler broadening detection by

transforming the radio frequency emission to produce frequency spectral data using a Fourier transformation;

and

determining an amplitude distribution within the frequency spectral data of the at least one radio frequency emission, wherein the amplitude distribution is a function of the multipath environment and the Doppler frequency observables.

27. The system of claim 27, further comprising a narrowband signal detector configured to optimize precision and sensitivity for motion dynamics of the system, wherein the narrowband signal detector facilitates transformation of the emission into Doppler frequency observables.

28. The system of claim 27, further comprising an emission pre-processor that uses spectral compression utilizing a non-linear operation upon the reflected radio frequency emission prior to transformation of the emission into Doppler frequency observables using Doppler broadening.

32. A method for providing physical state information of a mobile device, comprising

intercepting no more than two radio frequency emissions external to the mobile device;

transforming the no more than two radio frequency emissions into Doppler frequency observables;

determining speed of the mobile device from the Doppler frequency observables;

receiving acceleration observables from at least one linear accelerometer from a plurality of inertial sensors associated with the mobile device; and

processing the Doppler frequency observables and received acceleration observables to determine at least one member of the physical state of the mobile device, wherein the speed extracted from the Doppler frequency observables is used to constrain inertial drift error.

33. The method of claim 32, wherein the Doppler frequency observables are produced from the no more than two intercepted radio frequency emissions using spectral compression utilizing a non-linear operation to produce a set of observables suitable for physical state estimation.

34. The method of claim 33, wherein the set of observables produced using spectral compression includes at least one of physical characteristics in the form of amplitude, phase and temporal derivatives of the no more than two intercepted radio frequency emissions.

35. The method of claim 32, wherein speed is determined from the Doppler frequency observables using a narrowband signal detector configured to optimize precision and sensitivity for motion dynamics.

36. The method of claim 32, further comprising receiving acceleration observables from at least one rotational accelerometer from the plurality of inertial sensors associated with the mobile device.

37. The method of claim 32, comprising

receiving information related to the environment in which the mobile device is located from at least one environmental sensor associated with the mobile device;

and

processing the Doppler frequency observables and received acceleration observables to determine at least one member of the physical state of the mobile device further includes processing the received information related to the environment.

38. The method of claim 37, wherein the at least one environmental sensor associated with the mobile device provides at least one of magnetic compass or barometric pressure.

39. The method of claim 32, comprising

receiving information related to the location of the mobile device from at least one positioning sensor associated with the mobile device;

and

processing the Doppler frequency observables and received acceleration observables to determine at least one member of the physical state of the mobile device further includes processing the received information related to the location of the mobile device.

40. The method of claim 39, wherein the at least one positioning sensor associated with the mobile device utilizes at least one of a GPS/GNSS or assisted GPS/GNSS signals, Wi-Fi Received Signal Strength Indication (RSSI), Cell ID, Bluetooth beacon or RFID tag.

41. The method of claim 32, further comprising comparing the at least one member of the physical state of the mobile device with map information relative to the current physical location of the mobile device from a map cache to update the at least one member of the physical state of the mobile device.

42. The method of claim 32, further comprising estimating the step-size and step-rate of a person carrying the mobile device using the Doppler frequency observables and acceleration observables.

43. The method of claim 42, further comprising updating the at least one member of the physical state of the mobile device using the estimated step-size and step-rate.

44. The method of claim 32, wherein at least one of the two intercepted radio frequency emissions external to the mobile device is from a stationary source.

45. A method for providing physical state information relative to a mobile device in a GPS/GNSS obstructed environment, comprising

intercepting at least one at least one intercepted non-GPS/GNSS emission external to the mobile device;

transforming the at least one intercepted non-GPS/GNSS emission into Doppler frequency observables;

determining speed of the mobile device from the Doppler frequency observables;

receiving acceleration observables from at least one linear accelerometer from a plurality of inertial sensors associated with the mobile device; and

processing the Doppler frequency observables and received acceleration observables to determine at least one member of the physical state of the mobile device, wherein the speed extracted from the Doppler frequency observables is used to constrain inertial drift error.

46. The method of claim 45, wherein the Doppler frequency observables are produced from the at least one intercepted non-GPS/GNSS emission using spectral compression utilizing a non-linear operation to produce a set of observables suitable for physical state estimation by the physical state estimator.

47. The method of claim 46, wherein the set of observables produced using spectral compression includes at least one of physical characteristics in the form of amplitude, phase and temporal derivatives of the at least one intercepted non-GPS/GNSS emission.

48. The method of claim 45, wherein speed is determined from the Doppler frequency observables using a narrowband signal detector configured to optimize precision and sensitivity for motion dynamics.

49. The method of claim 45, further comprising receiving acceleration observables from at least one rotational accelerometer from the plurality of inertial sensors associated with the mobile device.

50. The method of claim 45, comprising

receiving information related to the environment in which the mobile device is located from at least one environmental sensor associated with the mobile device;

and

processing the Doppler frequency observables and received acceleration observables to determine at least one member of the physical state of the mobile device further includes processing the received information related to the environment.

51. The method of claim 50, wherein the at least one environmental sensor associated with the mobile device provides at least one of magnetic compass or barometric pressure.

52. The method of claim 45, comprising

receiving information related to the location of the mobile device from at least one positioning sensor associated with the mobile device;

and

processing the Doppler frequency observables and received acceleration observables to determine at least one member of the physical state of the mobile device further includes processing the received information related to the location of the mobile device.

53. The method of claim 52, wherein the at least one positioning sensor associated with the mobile device utilizes at least one of a GPS/GNSS or assisted GPS/GNSS signals, Wi-Fi Received Signal Strength Indication (RSSI), Cell ID, Bluetooth beacon or RFID tag.

54. The method of claim 45, further comprising comparing the at least one member of the physical state of the mobile device with map information relative to the current physical location of the mobile device from a map cache to update the at least one member of the physical state of the mobile device.

55. The method of claim 45, further comprising estimating the step-size and step-rate of a person carrying the mobile device using the Doppler frequency observables and acceleration observables.

56. The method of claim 55, further comprising updating the at least one member of the physical state of the mobile device using the estimated step-size and step-rate.

57. The method of claim 45, wherein the at least one intercepted non-GPS/GNSS emission external to the mobile device is from a stationary source.

58. A method for determining the speed of a mobile device in a multipath environment, comprising

intercepting at least one radio frequency emission traveling along a plurality of reflected paths from an emitter to a receiver associated with the mobile device;

transforming the reflected radio frequency emission into Doppler frequency observables using Doppler broadening detection, wherein the speed of the mobile device is determined from the Doppler frequency observables.

59. The method of claim 58, wherein the Doppler frequency observables are produced from the at least one radio frequency emission using spectral compression utilizing a non-linear operation to produce a set of observables suitable for physical state estimation.

60. The method of claim 59, wherein the set of observables produced using spectral compression includes at least one of physical characteristics in the form of amplitude, phase and temporal derivatives of the at least one intercepted non-GPS/GNSS emission.

61. The method of claim 58, wherein Doppler broadening detection comprises

transforming the radio frequency emission to produce frequency spectral data using a Fourier transformation;

and

determining an amplitude distribution within the frequency spectral data of the at least one radio frequency emission, wherein the amplitude distribution is a function of the multipath environment and the Doppler frequency observables.

62. The method of claim 58, wherein speed is determined from the Doppler frequency observables using a narrowband signal detector configured to optimize precision and sensitivity for motion dynamics.

63. The method of claim 58, wherein the at least one intercepted radio frequency emission external to the mobile device is from a stationary source.

64. The method of claim 58, wherein the at least one intercepted radio frequency emission is a Wi-Fi, cellular, Bluetooth, satellite radio or digital television signal.