Drop zone rally point beacon
First Claim
Patent Images
1. A near-field coupling beacon system comprising:
- a VLF/ELF band transmit loop antenna at one and only one transmit site;
a VLF/ELF band transmitter;
a plurality of ferrite loaded loop receive antennas at a receive site; and
a receiver detecting field polarity as received by said plurality of ferrite loaded loop receive antennas;
whereby near-field coupling between said transmit loop antenna and said plurality of ferrite-loaded loop receive antennas enables communication between said transmit site and said receive site.
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Accused Products
Abstract
A VLF beacon operates in the near field of the antenna, providing a low impedance (magnetic) wave located by employing simple amplitude gradient and phase alignment direction finding (DF) methods. When rotated, the beacon antenna radiates its signal with little attenuation. Beacon antennas include a loop antenna which has a 1/r3 B-field amplitude relationship with distance. The antenna radiation range is limited, but the detectable near field signal is strong. The receiver comprises a simple 2-channel RF front end with filtering and an A/D converter. The antenna for each channel is a much smaller ferrite rod loaded loop.
4 Citations
20 Claims
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1. A near-field coupling beacon system comprising:
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a VLF/ELF band transmit loop antenna at one and only one transmit site; a VLF/ELF band transmitter; a plurality of ferrite loaded loop receive antennas at a receive site; and a receiver detecting field polarity as received by said plurality of ferrite loaded loop receive antennas; whereby near-field coupling between said transmit loop antenna and said plurality of ferrite-loaded loop receive antennas enables communication between said transmit site and said receive site. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17)
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18. A near-field coupling beacon communication system comprising:
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a VLF/ELF band transmit loop antenna at one and only one transmit site; a VLF/ELF band transmitter; a plurality of ferrite loaded loop receive antennas at a receive site; and a receiver detecting field polarity as received by said plurality of ferrite loaded loop receive antennas; whereby near-field coupling between said transmit loop antenna and said plurality of ferrite-loaded loop receive antennas provides communication between remote outpost, Coalition Outpost (COP), Forward Operating Base (FOB) and beyond line-of-sight locations, wherein said near-field coupling beacon system provides communication over, around and through obstacles degrading propagation at RF communication frequencies outside frequencies of said near-field coupling beacon system, whereby bit error rates are maintained.
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19. A method for near-field direction finding comprising:
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transmitting a beacon signal from a VLF/ELF band transmit loop antenna at a single one and only one transmit site comprising a VLF/ELF band transmitter at a beacon site; receiving said beacon signal at a receive site comprising a plurality of ferrite loaded loop receive antennas at a receive site and a receiver detecting field polarity as received by said plurality of ferrite loaded loop receive antennas; whereby near-field coupling between said transmit loop antenna and said plurality of ferrite-loaded loop receive antennas enables communication between said transmit site and said receive site. - View Dependent Claims (20)
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Specification