ULTRA-SENSITIVE MAGNETIC FIELD RECEIVER CAPABLE OF OPERATING IN HIGH NOISE ENVIRONMENTS
First Claim
1. A method of controlling the operation of a system for geolocating objects within a monitored environment, wherein RF transmissions from tags associated with said objects are detected at a plurality of spaced apart monitoring locations containing tag transmission readers, and outputs of said tag transmission readers are processed to geolocate said tags and thereby their associated objects within said monitored environment, said method comprising the steps of:
- (a) generating, from at least a location of the monitored environment that is proximate to a region which a tagged object may enter, an unmodulated magnetic field having a constant frequency representative of information intended for a tag entering said region; and
(b) at a tag that has entered said region, detecting said unmodulated magnetic field and causing said tag to perform a prescribed function.
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Accused Products
Abstract
The unwanted influence a noise-source environment upon a modulated (e.g., FSK-encoded) magnetic field-based communication system is diminished by a non-modulated AC magnetic field communication scheme that uses a demodulatorless magnetic field detector. When installed in a tag to be tracked by a geolocation system, the demodulatorless detector responds when the tag comes within a prescribed proximity of the field generator producing the non-modulated AC magnetic field. The received signal is downconverted to baseband and processed to detect a valid AC magnetic field tone and indicate whether the tag is within a prescribed proximity of the AC magnetic field source.
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Citations
19 Claims
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1. A method of controlling the operation of a system for geolocating objects within a monitored environment, wherein RF transmissions from tags associated with said objects are detected at a plurality of spaced apart monitoring locations containing tag transmission readers, and outputs of said tag transmission readers are processed to geolocate said tags and thereby their associated objects within said monitored environment, said method comprising the steps of:
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(a) generating, from at least a location of the monitored environment that is proximate to a region which a tagged object may enter, an unmodulated magnetic field having a constant frequency representative of information intended for a tag entering said region; and
(b) at a tag that has entered said region, detecting said unmodulated magnetic field and causing said tag to perform a prescribed function. - View Dependent Claims (2, 3, 4, 5, 6)
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7. An arrangement for controlling the operation of a system for geolocating objects within a monitored environment, wherein RF transmissions from tags associated with said objects are detected at a plurality of spaced apart monitoring locations containing tag transmission readers, and outputs of said tag transmission readers are coupled to an object location subsystem which processes outputs of said tag transmissions to geolocate said tags and thereby their associated objects within said monitored environment, said arrangement comprising:
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at least one magnetic field generator located proximate to a region which a tagged object may enter, and being operative to generate an unmodulated magnetic field having a constant frequency representative of information intended for a tag entering said region; and
a magnetic field receiver installed on said tag and being operative to detect said unmodulated magnetic field and causing said tag to perform a prescribed function. - View Dependent Claims (8, 9, 10, 11, 12, 13, 15, 16, 17, 18, 19)
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14. A magnetic field receiver for use with a tag associated with an object to be tracked by a geolocation system containing at least one magnetic field generator, located proximate to a region which a tagged object may enter and being operative to generate an unmodulated magnetic field having a constant frequency representative of information intended for a tag entering said region, said magnetic field receiver comprising:
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a magnetic field detector that is operative to detect said unmodulated magnetic field; and
a processing circuit, coupled to said magnetic field detector and being operative to validate whether said detected magnetic field is a valid unmodulated magnetic field as generated by said at least one magnetic field generator.
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Specification