Patent ID: 7898419

Claim:
A networked radio frequency identification system for localizing an RFID tag at an endpoint represented as E.sub.i comprising: a plurality of radio frequency identification (RFID) tag readers, each RFID tag reader including at least one adjustable setting selected from RF signal strength, antenna gain, antenna polarization, and antenna orientation, and each RFID tag reader including a radio frequency (RF) interrogator; a computer in signal communication with the plurality of RFID tag readers over a network; and a software module for storage on and operable by the computer that localizes RFID tags based on information received from the RFID tag readers using hierarchical threshold limit calculations; wherein the hierarchical threshold limit calculations are based on accumulated reading factors from groups of settings for the RFID tag readers, wherein the software module is configured to: collect data for each setting of the RFID tag readers during an interval of time; calculate an aggregate result for each RFID tag reader based on an algorithm that uses a weighting function that includes W.sub.k,l and NR.sub.k,l as parameters where NR.sub.k,l represents the number of RFID tag readings at an interrogator ‘k’ configured with a setting ‘l’ and W.sub.k,l represents a weighting factor assigned to the interrogator ‘k’ configured with the setting ‘l’, and the algorithm spans all settings ‘l’ for the interrogator ‘k’; aggregate the calculated aggregate results based on a second weighting function to determine an aggregation result for an endpoint; and compare the aggregation result for the endpoint to at least one of a threshold value or threshold interval to determine whether the RFID tag is localized at the endpoint.