Wireless RFID networking systems and methods
First Claim
1. A method of determining tag positions based on a double difference calculation of measured tag signals in a distributed tag processing system comprising a set of tag readers, the method comprising:
- at each of a plurality of tag readers in the set of tag readers, receiving tag signals comprising tag data from a same plurality of tags residing in an overlapping coverage area of the plurality of tag readers;
at each particular tag reader in the plurality of tag readers, determining an initial position of each tag in the plurality of tags based on a first difference calculation between measurements of the signals received at the particular tag reader from all tags in the plurality of tags;
transmitting said initial position of each tag and said measurements of the received signals from each tag reader to an access point; and
at said access point, revising the position of each tag in the plurality of tags based on a second difference calculation between measurements of signals of each tag received at different tag readers in the plurality of tag readers.
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Abstract
Embodiments of the present invention include a wireless access point that acquires and processes radio frequency identification (RFID) information. The wireless access point may be coupled to a network of RFID readers over a wireless network. The RFID readers may read a plurality of RFID tags and transmit information to one or more readers. The readers may, in turn, transmit the RFID information to a wireless access point. The wireless access point may include a middleware layer for performing a variety of RFID data processing functions. In one embodiment, the wireless RFID reader network may be used to improve positioning of readers and tags, and may include a GPS system or position assisted GPS system at the reader and/or tag level.
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Citations
20 Claims
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1. A method of determining tag positions based on a double difference calculation of measured tag signals in a distributed tag processing system comprising a set of tag readers, the method comprising:
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at each of a plurality of tag readers in the set of tag readers, receiving tag signals comprising tag data from a same plurality of tags residing in an overlapping coverage area of the plurality of tag readers; at each particular tag reader in the plurality of tag readers, determining an initial position of each tag in the plurality of tags based on a first difference calculation between measurements of the signals received at the particular tag reader from all tags in the plurality of tags; transmitting said initial position of each tag and said measurements of the received signals from each tag reader to an access point; and at said access point, revising the position of each tag in the plurality of tags based on a second difference calculation between measurements of signals of each tag received at different tag readers in the plurality of tag readers. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10)
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11. A system for distributed tag management, the system comprising:
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a set of tags comprising tag data; a set of tag readers configured to retrieve tag data, a plurality of tag readers in the set of tag readers configured to receive signals from a same plurality of tags in the set of tags residing in an overlapping coverage area of the plurality of tag readers, each particular tag reader in the plurality of tag readers configured to determine an initial position of each tag in the plurality of tags based on a first difference calculation between measurements of the signals received at the particular tag reader from all tags in the plurality of tags; and a set of access points, at least one access point in the set of access points configured to (i) receive said initial position of each tag and said measurements of the received signals from each tag reader in the plurality of tag readers and (ii) revise the position of each tag in the plurality of tags based on a second difference calculation between measurements of signals of each tag received at different tag readers in the plurality of tag readers. - View Dependent Claims (12, 13, 14, 15, 16, 17, 18, 19, 20)
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Specification