Phase-based sensing system

• US 6,489,917 B2
• Filed: 11/06/2001
• Issued: 12/03/2002
• Est. Priority Date: 11/30/2000
• Status: Expired due to Term

• Current Assignee: Georgia Tech Research Corporation (University System of Georgia)
• Original Assignee: Georgia Tech Research Corporation (University System of Georgia)
• Inventors: Billington, Scott, Geisheimer, Jonathan, Greneker, Gene
• Primary Examiner(s): Sotomayor, John B.
• Application Number:
  US09/992,501
• Publication Number:
  US 20020097180A1
• Time in Patent Office: 392 Days
• Field of Search: 342/28, 342/98, 342/102, 342/104, 342/109, 342/114, 342/115, 342/118, 342/126, 342/127, 342/135
• US Class Current: 342/127
• CPC Class Codes: G01S 13/56 for presence detection presence detection using near field arrangements G01V3/00, e.g. G01V3/08, G01V3/12; burglar, theft or intruder alarms with electrical actuation G08B13/22 - G08B13/26
• CPC Class Codes: G01S 7/032 Constructional details for solid-state radar subsystems
• CPC Class Codes: G01S 7/2886 using I/Q processing

Abstract

A system for sensing and measuring the relative motion of an object, comprising a transceiver device configured to transmit a signal toward an object, a plurality of detectors offset in phase to receive the transmitted signal and a reflected signal, and a processor configured with logic to measure a phase shift resulting from the relative motion of the object between the transmitted signal and the reflected signal at the plurality of detectors, wherein the processor is further configured with the logic to relate the phase shift to the relative motion of the object.

Claims

1. A sensing and measurement method, comprising the steps of:

transmitting a reference signal at an object;

measuring the amplitude of the reference signal at two detectors, wherein the two detectors are offset in phase;

measuring the amplitude of a reflected signal at the two detectors;

mathematically relating the change in amplitude between the reference signal and the reflected signal at the two detectors to a change in phase, wherein the change in phase results from the relative motion of the object; and

mathematically relating the change in phase with the relative motion of the object, such that an object displacement measurement is provided with sub-wavelength resolution.

2. A method for sensing and measuring the relative motion of an object, comprising the steps of:

measuring a change in amplitude between a transmitted signal and a reflected signal at a plurality of detectors that are offset in phase;

relating the change in amplitude to a change in phase that results from the relative motion of the object; and

relating the change in phase to the motion of the object.

3. The method of claim 2, further comprising the step of mathematically deriving a phasor from the outputs of the detectors.

4. The method of claim 3, further comprising the step of using the relationship of a phasor angle between the detectors to a complete phasor revolution, wherein the phasor angle is mathematically related to the ratio of actual movement distance to a frequency wavelength of the transmitted signal.

5. The method of claim 4, further comprising the step of using the outputs of the detectors to derive amplitude coordinates for the phasor angle.

6. The method of claim 3, further comprising the step of counting the revolutions of the phasor to provide sub-wavelength resolution measurements of the relative displacement of the object for relative displacements greater than one wavelength.

7. The method of claim 2, further comprising the step of providing a displacement measurement from the change in phase for displacements of less than one wavelength and for displacements of greater than one wavelength.

8. The method of claim 2, further comprising the step of directing the transmitted signal downward from a vehicle to a surface located before at least one surface contact point of the vehicle.

9. The method of claim 8, further comprising the step of providing an indication of the topology of the surface relative to the source of the transmitted signal.

10. The method of claim 2, further comprising the step of using the measuring step and the relating steps to provide a measurement of machine movement.

11. The method of claim 2, further comprising the step of using the measuring step and the relating steps to provide a measurement of machine part movement.

12. The method of claim 2, further comprising the step of using the measuring step and the relating steps to provide a measurement of engine blade motion.

13. A method for sensing and measuring the relative motion of an object, comprising the steps of:

measuring a phase shift resulting from the relative motion of the object between a transmitted signal and a reflected signal at a plurality of detectors; and

relating the phase shift to the relative motion of the object.

14. The method of claim 13, further comprising the step of configuring the detectors to be offset in phase.

15. The method of claim 13, further comprising the step of measuring a change in amplitude between the transmitted signal and the reflected signal at the plurality of detectors.

16. The method of claim 15, further comprising the steps of relating the change in amplitude to the phase shift, and relating the phase shift to the motion of the object.

17. The method of claim 13, further comprising the step of mathematically deriving a phasor from the outputs of the detectors.

18. The method of claim 17, further comprising the step of using the relationship of a phasor angle between the detectors to a complete phasor revolution, wherein the phasor angle is mathematically related to the ratio of actual movement distance to a frequency wavelength of the transmitted signal.

19. The method of claim 18, further comprising the step of using the outputs of the detectors to derive amplitude coordinates for the phasor angle.

20. The method of claim 17, further comprising the step of counting the revolutions of the phasor to provide sub-wavelength resolution measurements of the relative displacement of the object for relative displacements greater than one wavelength.

21. The method of claim 13, further comprising the step of providing a displacement measurement from the change in phase for displacements of less than one wavelength and for displacements of greater than one wavelength.

22. The method of claim 13, further comprising the step of directing the transmitted signal downward from a vehicle to a surface located before at least one surface contact point of the vehicle.

23. The method of claim 22, further comprising the step of providing an indication of the topology of the surface relative to the source of the transmitted signal.

24. The method of claim 13, further comprising the step of using the measuring and the relating steps to provide a measurement of machine movement.

25. The method of claim 13, further comprising the step of using the measuring and the relating steps to provide a measurement of machine part movement.

26. The method of claim 13, further comprising the step of using the measuring and the relating steps to provide a measurement of engine blade motion.

27. A sensing and measurement system, comprising:

a transceiver device configured to transmit a reference signal toward an object, wherein the transceiver device is further configured with two detectors offset in phase to receive a reflected signal; and

a processor configured with logic to measure the amplitude of the reference signal at the two detectors, wherein the processor is further configured with the logic to measure the amplitude of the reflected signal at the two detectors, wherein the processor is further configured with the logic to mathematically relate the change in amplitude between the reference signal and the reflected signal at the two detectors to a change in phase, wherein the change in phase results from the relative motion of the object, wherein the processor is further configured with the logic to mathematically relate the change in phase with the relative motion of the object, such that an object displacement measurement is provided with sub-wavelength resolution.

28. A system for sensing and measuring the relative motion of an object, comprising:

a transceiver device configured to transmit a signal toward an object;

a plurality of signal detectors offset in phase to receive the transmitted signal and a reflected signal; and

a processor configured with logic to measure a change in amplitude between the transmitted signal and the reflected signal at the plurality of detectors, wherein the processor is further configured with the logic to relate the change in amplitude to a change in phase that results from the relative motion of the object, wherein the processor is further configured with the logic to relate the change in phase to the motion of the object.

29. The system of claim 28, wherein the processor is further configured with the logic to mathematically derive a phasor from the outputs of the detectors.

30. The system of claim 29, wherein the processor is further configured with the logic to use the relationship of a phasor angle between the detectors to a complete phasor revolution, wherein the phasor angle is mathematically related to the ratio of actual movement distance to a frequency wavelength of the transmitted signal.

31. The system of claim 30, wherein the processor is further configured with the logic to use the outputs of the detectors to derive amplitude coordinates for the phasor angle.

32. The system of claim 29, wherein the processor is further configured with the logic to count the revolutions of the phasor to provide sub-wavelength resolution measurements of the relative displacement of the object for relative displacements greater than one wavelength.

33. The system of claim 28, wherein the processor is further configured with the logic to provide a displacement measurement from the change in phase for displacements of less than one wavelength and for displacements of greater than one wavelength.

34. The system of claim 28, wherein the transceiver is further configured to direct the transmitted signal downward from a vehicle to a surface located before at least one surface contact point of the vehicle.

35. The system of claim 34, wherein the processor is further configured with the logic to provide an indication of the topology of the surface relative to the source of the transmitted signal.

36. The system of claim 28, wherein the processor is further configured with the logic to provide a measurement of machine movement.

37. The system of claim 28, wherein the processor is further configured with the logic to provide a measurement of machine part movement.

38. The system of claim 28, wherein the processor is further configured with the logic to provide a measurement of engine blade motion.

39. A system for sensing and measuring the relative motion of an object, comprising:

a transceiver device configured to transmit a signal toward an object;

a plurality of detectors offset in phase to receive the transmitted signal and a reflected signal; and

a processor configured with logic to measure a phase shift resulting from the relative motion of the object between the transmitted signal and the reflected signal at the plurality of detectors, wherein the processor is further configured with the logic to relate the phase shift to the relative motion of the object.

40. The system of claim 39, wherein the processor is further configured with the logic to measure a change in amplitude between the transmitted signal and the reflected signal at the plurality of detectors.

41. The system of claim 40, wherein the processor is further configured with the logic to relate the change in amplitude to the phase shift, and relate the phase shift to the motion of the object.

42. The system of claim 39, wherein the processor is further configured with the logic to mathematically derive a phasor from the outputs of the detectors.

43. The system of claim 42, wherein the processor is further configured with the logic to use the relationship of a phasor angle between the detectors to a complete phasor revolution, wherein the phasor angle is mathematically related to the ratio of actual movement distance to a frequency wavelength of the transmitted signal.

44. The system of claim 43, wherein the processor is further configured with the logic to use the outputs of the detectors to derive amplitude coordinates for the phasor angle.

45. The system of claim 42, wherein the processor is further configured with the logic to count the revolutions of the phasor to provide sub-wavelength resolution measurements of the relative displacement of the object for relative displacements greater than one wavelength.

46. The system of claim 39, wherein the processor is further configured with the logic to provide a displacement measurement from the change in phase for displacements of less than one wavelength and for displacements of greater than one wavelength.

47. The system of claim 39, wherein the transceiver is further configured to direct the transmitted signal downward from a vehicle to a surface located before at least one surface contact point of the vehicle.

48. The system of claim 47, wherein the processor is further configured with the logic to provide an indication of the topology of the surface relative to the source of the transmitted signal.

49. The system of claim 39, wherein the processor is further configured with the logic to provide a measurement of machine movement.

50. The system of claim 39, wherein the processor is further configured with the logic to provide a measurement of machine part movement.

51. The system of claim 39, wherein the processor is further configured with the logic to provide a measurement of engine blade motion.

52. A processing system on a recordable medium, the processing system comprising:

logic configured to measure the amplitude of a reference signal at two detectors;

logic configured to measure the amplitude of a reflected signal at the two detectors;

logic configured to mathematically relate the change in amplitude between the reference signal and the reflected signal at the two detectors to a change in phase, wherein the change in phase results from the relative motion of the object; and

logic configured to mathematically relate the change in phase with the relative motion of the object, such that an object displacement measurement is provided with sub-wavelength resolution.

53. A processing system on a recordable medium, the processing system comprising:

logic configured to measure a phase shift resulting from the relative motion of an object between a transmitted signal and a reflected signal at a plurality of detectors, wherein the plurality of detectors are offset in phase; and

logic configured to relate the phase shift to the relative motion of the object.

54. The processing system of claim 53, wherein the logic is further configured to measure a change in amplitude between the transmitted signal and the reflected signal at the plurality of detectors.

55. The processing system of claim 54, wherein the logic is further configured to relate the change in amplitude to the phase shift, and relate the phase shift to the motion of the object.

56. The processing system of claim 53, wherein the logic is further configured to mathematically derive a phasor from the outputs of the detectors.

57. The processing system of claim 56, wherein the logic is further configured to use the relationship of a phasor angle between the detectors to a complete phasor revolution, wherein the phasor angle is mathematically related to the ratio of actual movement distance to a frequency wavelength of the transmitted signal.

58. The system of claim 57, wherein the logic is further configured to use the outputs of the detectors to derive amplitude coordinates for the phasor angle.

59. The processing system of claim 56, wherein the logic is further configured to count the revolutions of the phasor to provide sub-wavelength resolution measurements of the relative displacement of the object for relative displacements greater than one wavelength.

60. The processing system of claim 53, wherein the logic is further configured to provide a displacement measurement from the change in phase for displacements of less than one wavelength and for displacements of greater than one wavelength.

61. A method for sensing and measuring the relative motion of an object, comprising the steps of:

multiplying an unmodulated transmitted signal with a reflected signal at a plurality of detectors;

measuring a phase shift resulting from the relative motion of the object between the unmodulated transmitted signal and the reflected signal; and

relating the phase shift to the relative motion of the object.

62. The method of claim 61, further comprising the step of configuring the detectors to be offset in phase.

63. The method of claim 61, further comprising the step of measuring a change in amplitude between the unmodulated transmitted signal and the reflected signal at the plurality of detectors.

64. The method of claim 63, further comprising the steps of:

relating the change in amplitude to the phase shift; and

relating the phase shift to the motion of the object.

65. The method of claim 61, further comprising the step of mathematically deriving a phasor from the outputs of the detectors.

66. The method of claim 65, further comprising the step of using the relationship of a phasor angle between the detectors to a complete phasor revolution, wherein the phasor angle is mathematically related to the ratio of actual movement distance to a frequency wavelength of the unmodulated transmitted signal.

67. The method of claim 66, further comprising the step of using the outputs of the detectors to derive amplitude coordinates for the phasor angle.

68. The method of claim 65, further comprising the step of counting the revolutions of the phasor to provide sub-wavelength resolution measurements of the relative displacement of the object for relative displacements greater than one wavelength.

69. The method of claim 61, further comprising the step of providing a displacement measurement from the change in phase for displacements of less than one wavelength and for displacements of greater than one wavelength.

70. The method of claim 61, further comprising the step of directing the transmitted signal downward from a vehicle to a surface located before at least one surface contact point of the vehicle.

71. The method of claim 70, further comprising the step of providing an indication of the topology of the surface relative to the source of the unmodulated transmitted signal.

72. The method of claim 61, further comprising the step of using the measuring and the relating steps to provide a measurement of machine movement.

73. The method of claim 61, further comprising the step of using the measuring and the relating steps to provide a measurement of machine part movement.

74. The method of claim 61, further comprising the step of using the measuring and the relating steps to provide a measurement of engine blade motion.

75. The method of claim 61, wherein the unmodulated transmitted signal is transmitted at defined intervals.

76. A system for sensing and measuring the relative motion of an object, comprising:

a transceiver device configured to transmit an unmodulated signal toward an object;

a plurality of detectors, offset in phase, that multiply the unmodulated transmitted signal and a reflected signal; and

a processor configured with logic to measure a phase shift resulting from the relative motion of the object between the unmodulated transmitted signal and the reflected signal, wherein the processor is further configured with the logic to relate the phase shift to the relative motion of the object.

77. The system of claim 76, wherein the processor is further configured with the logic to measure a change in amplitude between the unmodulated transmitted signal and the reflected signal at the plurality of detectors.

78. The system of claim 77, wherein the processor is further configured with the logic to relate the change in amplitude to the phase shift, and relate the phase shift to the motion of the object.

79. The system of claim 76, wherein the processor is further configured with the logic to mathematically derive a phasor from the outputs of the detectors.

80. The system of claim 79, wherein the processor is further configured with the logic to use the relationship of a phasor angle between the detectors to a complete phasor revolution, wherein the phasor angle is mathematically related to the ratio of actual movement distance to a frequency wavelength of the unmodulated transmitted signal.

81. The system of claim 80, wherein the processor is further configured with the logic to use the outputs of the detectors to derive amplitude coordinates for the phasor angle.

82. The system of claim 79, wherein the processor is further configured with the logic to count the revolutions of the phasor to provide sub-wavelength resolution measurements of the relative displacement of the object for relative displacements greater than one wavelength.

83. The system of claim 76, wherein the processor is further configured with the logic to provide a displacement measurement from the change in phase for displacements of less than one wavelength and for displacements of greater than one wavelength.

84. The system of claim 76, wherein the transceiver is further configured to direct the unmodulated transmitted signal downward from a vehicle to a surface located before at least one surface contact point of the vehicle.

85. The system of claim 84, wherein the processor is further configured with the logic to provide an indication of the topology of the surface relative to the source of the unmodulated transmitted signal.

86. The system of claim 76, wherein the processor is further configured with the logic to provide a measurement of machine movement.

87. The system of claim 76, wherein the processor is further configured with the logic to provide a measurement of machine part movement.

88. The system of claim 76, wherein the processor is further configured with the logic to provide a measurement of engine blade motion.

89. The system of claim 76, wherein the logic resides on a computer readable medium.

90. The system of claim 76, wherein the unmodulated transmitted signal is transmitted at defined intervals.