Object locating apparatus, system and high-gain, high-selectivity antennae therefor

• US 20100026578A1
• Filed: 07/30/2008
• Published: 02/04/2010
• Est. Priority Date: 07/30/2008
• Status: Active Grant

• Current Assignee: Alpzite, LLC
• Original Assignee: Alpzite, LLC
• Inventors: MacDuff, Ian G., Shafer, Thomas O., Furnanz, Ken
• Granted Patent: US 8,138,988 B2
• Time in Patent Office: Days
• US Class Current: 342/419
• CPC Class Codes: G01S 13/825 with exchange of information between interrogator and responder
• CPC Class Codes: G01S 7/06 Cathode-ray tube displays or other two dimensional or three-dimensional displays
• CPC Class Codes: H01Q 1/38 formed by a conductive layer on an insulating support patch antennas H01Q9/0407; microstrip dipole antennas H01Q9/065; microstrip slot antennas H01Q13/106; transmission line microstrip antennas H01Q13/206; manufacturing reflecting surfaces using insulating material for supporting the reflecting surface H01Q15/142
• CPC Class Codes: H01Q 11/08 Helical antennas
• CPC Class Codes: H01Q 19/30 the primary active element being centre-fed and substantially straight, e.g. Yagi antenna

Abstract

The invented system includes a beacon affixed to the object subject to loss and a tracker held by the owner of the lost object, the tracker repeatedly, electronically ‘interrogating’ the beacon with a radio frequency (RF) signal, the beacon repeatedly responding to the interrogation, and the tracker effectively triangulating to determine the lost object'"'"'s nominal location by a measure of distance and direction. In accordance with one embodiment of the invention, the tracker includes one or more antenna each coupled with a power amplifier to determine in real time the distance and direction of the beacon from the tracker. In this embodiment, the tracker indicates both distance and direction of the object-affixed beacon to the tracker-holding owner via a simple color-coded light array. In one embodiment of the invention, the invented antenna of which there is one (or more) includes a helically wound conductor of elliptical cross section disposed around the hollow interior surface of a hollow mandrel.

Claims

1. A lost-object locating system comprising:

a hand-grippable tracker configured repeatedly to emit a distinctive query signal therefrom; and

a beacon affixable to an object subject to loss, the beacon configured repeatedly to transmit a response signal in response to the repeatedly emitted tracker query signal,

the tracker including at least one directionally biased receiver antennae coupled therewith to determine in real time at least one of a relative distance and direction of the beacon relative to the tracker as a user navigates using the hand-grippable tracker.

2. The system of claim 1, wherein the tracker further includes a display indicating the at least one of a determined relative distance and direction of the beacon relative to the tracker.

3. The system of claim 2, wherein the operating range between the beacon and the tracker is greater than or equal to approximately 1.0 mile.

4. The system of claim 2, wherein the display includes two or more color coded lights.

5. The system of claim 1, wherein each of the at least one antenna is of a planar Yagi array type.

6. The system of claim 1, wherein each of the at least one antenna includes a conductor winding along a helical path around a transmission axis.

7. The system of claim 6, wherein each of the at least one winding is approximately elliptical in cross section.

8. The system of claim 7, wherein a ratio of the major to minor axis of the elliptical cross section is greater than approximately 3 to 1.

9. The system of claim 8, wherein the ratio is greater than approximately 5 to 1.

10. The system of claim 1, wherein the tracker further includes at least one signal booster amplifier operatively coupled with the at least one antenna.

11. The system of claim 1, wherein the at least one antenna is two or more antennae configured to have angularly divergent central axes.

12. A transmission antenna for use in an object locating system, the antenna comprising:

a conductor extending helically from a plane perpendicular to a central axis of the antenna,

the conductor extending helically along the central axis, a described helix thereof being characterized by an approximately elliptical cross section.

13. The antenna of claim 12 further comprising:

a solid or hollow mandrel,

the conductor being disposed around an outer surface of the mandrel.

14. The antenna of claim 12 further comprising:

a hollow mandrel,

the conductor being disposed around an inner surface of the mandrel.

15. The antenna of claim 12 further comprising:

a ground plane parallel to the perpendicular plane, the ground plane being electrically isolated from the conductor.

16. The antenna of claim 12, wherein half-power beam-width of the antenna is less than approximately thirty-five degrees.

17. The antenna of claim 12, wherein the antenna is configured to mount to a printed circuit board (PCB).

18. The antenna of claim 12, wherein the antenna is tuned to receive at a defined nominal wavelength λ

₀, and wherein the circumference of the elliptical cross section of the antenna is dimensioned between approximately 0.25 λ

₀ and 1.75 λ

₀.

19. The antenna of claim 18, wherein the circumference of the elliptical cross section of the antenna is dimensioned between approximately 0.5 λ

₀ and 1.5 λ

₀.

20. The antenna of claim 19, wherein the circumference of the elliptical cross section of the antenna is dimensioned between approximately 0.75 λ

₀ and 1.25 λ

₀.

21. A lost-object locating apparatus comprising:

one or more beacons each affixable to an object subject to loss and each configured repeatedly to transmit a signal substantially omni-directionally, and

a hand-grippable tracker configured to receive each signal transmitted from the one or more beacons and to determine the distance and direction of the one or more beacons from the tracker.

22. The apparatus of claim 21, wherein the range of the locating apparatus is greater than approximately 1.0 mile.

23. The apparatus of claim 21, wherein the apparatus includes a pairing mode of operation relative to the one or more beacons, and wherein the tracker is capable after the pairing of receiving differentiated signals from up to three of the one or more beacons, and wherein the tracker is capable of indicating both proximity and direction of the up to three of the one or more beacons relative to the tracker.

24. An object locating system comprising:

one or more beacons each comprising a means to transmit a radio signal to a tracker;

one or more trackers each comprising a means to receive a radio signal from the one or more beacons, a means to determine at least one of a direction and distance to the one or more beacons, and a means to indicate at least one of the determined direction and distance to the one or more beacons.

25. The system of claim 24, wherein the one or more beacons each is portable.

26. The system of claim 25, wherein the volume of each of the one or more beacons is less than approximately 2.5 cubic inches (in³).

27. The system of claim 26, wherein the volume of each of the one of more beacons is less than approximately 1.5 in³.

28. The system of claim 27, wherein the volume of each of the one or more beacons is less than approximately 1.0 in³.

29. The system of claim 28, wherein the largest measurement in the narrowest dimension of each of the one or more beacons is less than approximately 0.5 inches.

30. The system of claim 29, wherein the largest measurement in the narrowest dimension of each of the one or more beacons is less than approximately 0.4 inches.

31. The system of claim 24, wherein each of the one or more beacons is configured to be affixed to another object.

32. The system of claim 24, wherein each of the one or more trackers is portable and hand-grippable.

33. The system of claim 24 in which each of the one or more trackers includes a forward directional antenna portion, wherein each of the one or more trackers has a rearward hand-grippable portion located behind the directional antenna portion.

34. The system of claim 33, wherein each directional antenna portion includes a helical antenna tuned to receive at a defined nominal free-space wavelength λ

₀, and wherein the circumference of the elliptical cross section of the antenna is dimensioned between approximately 0.75 λ

₀ and 1.25 λ

₀.

35. The system of claim 33, wherein each directional antenna portion includes a helical antenna having a substantially uniform nominal winding pitch of between approximately 12 and 16 degrees.

36. The system of claim 35, wherein each directional antenna portion includes a helical antenna having a substantially uniform nominal winding pitch of approximately 14 degrees.

37. The system of claim 36, wherein each directional antenna portion includes a ground plane oriented substantially perpendicular to a major axis of the helical antenna.

38. The system of claim 35, wherein the ground plane is a part of a printed circuit board (PCB).

39. The system of claim 32, wherein the cross-sectional shape of the helical antenna is an ellipse.

40. The system of claim 37, wherein the eccentricity of the ellipse is between approximately 3 and 10.

41. The system of claim 24, wherein each of the one or more trackers is configured to be affixed to another object.

42. The system of claim 33, wherein each directional antenna portion includes a Yagi antenna tuned to receive at a defined nominal free-space wavelength λ

₀, the Yagi antenna comprising plural spaced-apart Yagi elements comprising an active drive element, a passive reflector element and one or more passive director elements configured as plural conductors on an electrically isolated mast.

43. The system of claim 42, wherein the Yagi elements are patterned on a printed circuit board (PCB).

44. The system of claim 43 wherein the PCB further provides for electrical interconnections and mounting of transceiver electronics of the tracker.

45. The system of claim 44, wherein the Yagi elements and the electronics share a ground plane on the PCB.

46. The system of claim 45, wherein at least the drive element is coupled with the electronics in the form of a PCB transmission line.

47. The system of claim 42, wherein the drive element is approximately 0.5 λ

₀ in length.

48. The system of claim 42, wherein the reflector element is approximately 1.05 λ

₀ in length.

49. The system of claim 42, wherein each of the one or more director elements is approximately 0.95 λ

₀ in length.

50. The system of claim 42 in which there are plural adjacent pair-wise director elements, wherein a spacing between the pair-wise director elements is between approximately 0.1 λ

₀ and 0.5 λ

₀.

51. The system of claim 42, wherein a spacing between the drive element and the reflector element is between approximately 0.1 λ

₀ and 0.25 λ

₀.

52. The system of claim 42, wherein at least one of the one or more director elements is alternately removable and attachable by a user.

53. The system of claim 44, wherein at least the drive element is coupled with the electronics in the form of a coaxial cable.

54. The system of claim 33, wherein each of the one or more trackers includes a plurality of antennae, wherein the means to determine is coupled with a plurality of signals received by the plurality of antennae.

55. The system of claim 54, wherein the means to determine includes a triangulation technique.

56. The system of claim 54, wherein the means to determine includes a pseudo-Doppler technique.

57. The system of claim 54, wherein the means to determine includes a Watson-Watt technique.

58. The system of claim 24, wherein the beacon includes a substantially omnidirectional beacon antenna portion.

59. The system of claim 58, wherein the beacon antenna portion includes a substantially omnidirectional microstrip antenna (OMA).

60. The system of claim 58, wherein the beacon antenna includes an inverted-F antenna.

61. The system of claim 58, wherein the beacon antenna includes a meander line antenna.

62. The system of claim 24, wherein each of the one or more beacons is powered by one or more batteries.

63. The system of claim 62, wherein a charge status of the one or more beacon batteries is capable of being determined.

64. The system of claim 63, wherein the determined charge status of the one or more beacon batteries is radio frequency (RF) transmitted to the each of the one or more trackers., and wherein the determined charge status of the one or more beacon batteries is annunciated at the one or more trackers.

65. The system of claim 64, wherein the one or more beacon batteries is at least one of rechargeable and replaceable.

66. The system of claim 24, wherein each of the one or more trackers is powered by one or more tracker batteries.

67. The system of claim 66, wherein a charge status of the one or more tracker batteries is capable of being determined.

68. The system of claim 67, wherein the determined charge status of the one or more tracker batteries is annunciated at the one or more trackers.

69. The system of claim 68, wherein the one or more tracker batteries is at least one of rechargeable and replaceable.

70. The system of claim 24, wherein each of the one or more trackers uses a unique beacon identification (ID) selectively to pair with only one and to ignore all other of the one or more beacons.

71. The system of claim 70, wherein each of the one or more trackers comprises a switch for user selection of which one beacon to locate.

72. The system of claim 71, wherein each of the one or more trackers comprises an indicator of which one beacon to locate.

73. The system of claim 72, wherein each of the one or more beacons comprises a beacon transmitter for transmitting the unique beacon ID as a packet of digital beacon data.

74. The system of claim 73, wherein the packet of digital beacon data is forward error corrected.

75. The system of claim 24, wherein each of the one or more beacons uses a unique tracker identification (ID) selectively to pair with only one and to ignore other of the one or more trackers.

76. The system of claim 70, wherein each of the one or more beacons comprises a switch for user selection of which one tracker to respond.

77. The system of claim 71, wherein each of the one or more beacons comprises an indicator of which one tracker it is selected to respond to.

78. The system of claim 72, wherein each of the one or more trackers comprises a tracker transmitter for transmitting the unique tracker identification (ID) as a packet of digital tracker ID data.

79. The system of claim 73, wherein the packet of digital tracker ID data is forward error corrected.

80. The system of claim 24, wherein a plurality of the one or more trackers is used simultaneously to locate a plurality of the one or more beacons.

81. The system of claim 24, wherein each of the one or more trackers comprises a microprocessor and a radio.

82. The system of claim 81, wherein the microprocessor and radio are integrated into a single printed circuit board-mountable integrated circuit package.

83. The system of claim 24, wherein each of the one or more trackers is configured to receive a signal from each of the one or more beacons at a distance of more than approximately 1.0 mile.

84. The system of claim 24, wherein each of the one or more trackers is configured to identify each of the one or more beacons at a distance of more than approximately 1.0 mile.

85. The system of claim 24, wherein each of the one or more trackers comprises a means of determining a direction to each of the one or more beacons at a distance of at least approximately 50 feet.

86. The system of claim 85, wherein each of the one or more trackers comprises a means of indicating a direction to each of the one or more beacons.

87. The system of claim 86, wherein the means of indicating direction comprises a compass and a microprocessor for processing data therefrom and for monitoring antenna signal strength data.

88. The system of claim 86, wherein each of the means of indicating direction includes an analog meter.

89. The system of claim 86, wherein each of the means of indicating direction includes an array of plural lights.

90. The system of claim 86, wherein each of the one or more trackers further comprises a means of indicating a distance to each of the one or more beacons.

91. The system of claim 90, wherein each of the means of indicating distance includes an analog meter.

92. The system of claim 90, wherein each of the means of indicating distance includes an array of plural lights.

93. The system of claim 24, wherein each of the one or more trackers comprises a means to transmit a signal to the one or more beacons.

94. The system of claim 93, wherein each of the one or more means to transmit comprises a power amplifier in a transmit path.

95. The system of claim 94, wherein the transmit signal is used by the one or more beacons to awaken the beacon from a quiescent battery-save state.

96. The system of claim 94, wherein each of the one or more beacons comprises a wake-up transmit signal receiver and a means for awakening the beacon from a quiescent battery-save state.

97. The system of claim 24, wherein each of the one or more beacons includes a trigger circuit to awaken the beacon from a quiescent battery-save state, the trigger circuit being configured to be triggered by a signal from an invisible perimeter fence.

98. The system of claim 24, wherein each of the one or more trackers includes a low-noise amplifier in a receive signal path between an antenna and a microprocessor.

99. The system of claim 24, wherein signals passed between the one or more trackers and the one or more beacons are encoded as digital data.

100. The system of claim 99, wherein the digital data are conveyed at a variable rate.

101. The system of claim 100, wherein a higher data rate is used at a shorter range between the one or more trackers and the one or more beacons, and wherein a lower data rate is used at a longer range therebetween.

102. The system of claim 25, wherein each of the one or more trackers comprises a directional antenna, a power amplifier operatively coupled with the antenna, a microprocessor operatively coupled with the power amplifier, and a digital compass or accelerometer operatively coupled with the microprocessor to determine distance and direction of the one or more beacons.