Reverse infrastructure location system and method
First Claim
1. A system by which an object can locate itself within an area, comprising:
- multiple radio frequency identification (RFID) tags positioned at known locations within the area; and
a moveable RFID tag reader associated with the object and in signaling contact with at least some of the RFID tags, said tag reader for interrogating the at least some of the RFID tags and receiving information therefrom related to their known locations, and for using such known location information to establish its own position within the area.
1 Assignment
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Accused Products
Abstract
Methods and apparatus are provided to locate a terminal within a workspace. Radio frequency identification (RFID) tags are provided in known locations, preferably in, on or adjacent the light fixtures or other workspace infrastructure. The terminal comprises an RFID tag interrogation transceiver, processor and memory. The transceiver interrogates the tags which respond with information correlatable with their unique locations. The terminal determines its locations relative to the known locations of responding tags by, for example, varying its transmit power and/or receiver sensitivity and/or by trilateration using, for example, phase or time difference of arrival measurements on the tag response signals. Once it has determined its own location it may transmit or otherwise announce its location as desired by the user. In a preferred embodiment, the natural electromagnetic radiation and/or RADAR cross section backscatter from fluorescent type fixtures, modulated with their position information, acts as the RFID infrastructure beacon.
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Citations
25 Claims
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1. A system by which an object can locate itself within an area, comprising:
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multiple radio frequency identification (RFID) tags positioned at known locations within the area; and
a moveable RFID tag reader associated with the object and in signaling contact with at least some of the RFID tags, said tag reader for interrogating the at least some of the RFID tags and receiving information therefrom related to their known locations, and for using such known location information to establish its own position within the area. - View Dependent Claims (2, 3, 4, 5, 6, 7)
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8. A method for determining the position of an object within an area having multiple RFID tags in known locations, comprising:
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interrogating a tag and receiving information therefrom, wherein such information directly or indirectly identifies the tag location;
determining proximity of the object to the interrogated tag; and
repeating the interrogating and determining steps for the same or different tags to obtain a substantially unique position of the object relative to the same or different tags. - View Dependent Claims (9, 10, 11, 12, 13, 14, 15, 16)
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17. A method for determining the position of a terminal in a workspace having beacon transmitters in known locations emitting unique IDs, comprising:
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obtaining unique ID signals from one or more of the beacon transmitters;
determining locations of the one or more beacon transmitters from the unique ID signals; and
determining the terminal location based on the locations of the one or more beacon transmitters whose unique ID signals were received. - View Dependent Claims (18, 19)
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20. A system for determining the location of a terminal within a workspace, comprising:
multiple elements in known locations relative to the workspace, each element having a gaseous region whose RF impedance is time varying in a manner embodying information on the known location of such individual element; and
wherein the terminal comprises;
a detector wirelessly coupled to at least some of the gaseous regions, adapted to detect the time varying RF impedance containing information on the location thereof; and
a processor coupled to the detector for analyzing the time varying RF impedance detected by the detector and determining the location of the terminal relative to the workspace at least in part from the information contained in such time varying RF impedance. - View Dependent Claims (21, 22, 23, 24)
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25. A movable radio frequency identification (RFID) tag reader coupled to an object, for locating the object within an area equipped with a plurality of RFID tags at known positions within the area, the RFID tag reader comprising:
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a transmitter for interrogating at least some of the RFID tags; and
a receiver for receiving information from the interrogated RFID tags and utilizing the information to establish the position of the tag reader within the area.
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Specification