Proximity monitoring system and associated methods
First Claim
1. A proximity detection system comprising:
- a magnetic field generator for generating a rotating magnetic field having a decreasing intensity over an increasing separation distance;
a magnetic field detector being relatively movable and generating a crossing indication based upon an intensity threshold in the rotating magnetic field being crossed as a threshold separation distance from said magnetic field generator is crossed; and
a transmitter for transmitting a signal relating to the crossing indication from said magnetic field detector.
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Accused Products
Abstract
A proximity detection system includes a magnetic field generator for generating a rotating magnetic field having a decreasing intensity over an increasing separation distance, and a magnetic field detector being relatively movable and generating a crossing indication based upon an intensity threshold in the rotating magnetic field being crossed as a threshold separation distance from the magnetic field generator is crossed. The system may also include a transmitter for transmitting a signal relating to the crossing indication from the magnetic field detector. The magnetic field generator may generate a substantially constant amplitude rotating magnetic field vector, and the magnetic field detector may comprise a plurality of orthogonal detection coils. The rotating magnetic field provides a relatively sharp cut-off threshold separation distance defining a perimeter for proximity detection.
39 Citations
46 Claims
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1. A proximity detection system comprising:
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a magnetic field generator for generating a rotating magnetic field having a decreasing intensity over an increasing separation distance;
a magnetic field detector being relatively movable and generating a crossing indication based upon an intensity threshold in the rotating magnetic field being crossed as a threshold separation distance from said magnetic field generator is crossed; and
a transmitter for transmitting a signal relating to the crossing indication from said magnetic field detector. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16)
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17. A proximity detection system comprising:
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a magnetic field generator for generating a modulated rotating magnetic field having a decreasing intensity over an increasing separation distance, the modulated rotating magnetic field being modulated to have at least one of a predetermined direction and predetermined speed;
a magnetic field detector being relatively movable and generating a crossing indication based upon an intensity threshold in the modulated rotating magnetic field being crossed as a threshold separation distance from said magnetic field generator is crossed; and
a transmitter for transmitting a signal relating to the crossing indication from said magnetic field detector. - View Dependent Claims (18, 19, 20, 21, 22, 23, 24, 25, 26)
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27. A proximity detection system comprising:
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a magnetic field generator for generating a spread spectrum modulated rotating magnetic field having a decreasing intensity over an increasing separation distance;
a magnetic field detector being relatively movable and generating a crossing indication based upon an intensity threshold in the spread spectrum modulated rotating magnetic field being crossed as a threshold separation distance from said magnetic field generator is crossed; and
a transmitter for transmitting a signal relating to the crossing indication from said magnetic field detector. - View Dependent Claims (28, 29, 30, 31, 32, 33, 34, 35, 36, 37)
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38. A method for proximity detection comprising:
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generating a rotating magnetic field having a decreasing intensity over an increasing separation distance from a base station; and
providing a tag for an object or person that is relatively movable with respect to the base station, the tag comprising a magnetic field detector for generating a crossing indication based upon an intensity threshold in the rotating magnetic field being crossed as a threshold separation distance from the base station is crossed, and a transmitter for transmitting a signal relating to the crossing indication. - View Dependent Claims (39, 40, 41, 42, 43, 44, 45, 46)
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Specification