Systems and methods for object localization and path identification based on rfid sensing

Abstract

A networked radio frequency identification system includes a plurality of radio frequency identification (RFID) tag readers, a computer in signal communication with the 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 a network model having endpoints and oriented links. In an additional example, at least one of the RFID tag readers includes an adjustable configuration setting selected from RF signal strength, antenna gain, antenna polarization, and antenna orientation. In a further aspect, the system localizes RFID tags based on hierarchical threshold limit calculations. In an additional aspect, the system controls a locking device associated with an access point based on localization of an authorized RFID tag at the access point and reception of additional authorizing information from an input device.

The embodiments of the invention in which an exclusive property or privilege is claimed are defined as follows: 
     
         1 . A radio frequency identification (RFID) system for localizing at least two RFID tags which have tag to tag communication capabilities, the system comprising:
 a plurality of radio frequency identification (RFID) tag readers;   a computer in signal communication with the plurality of RFID tag readers over a network;   the computer being configured to operate a software module that localizes the RFID tag based on data received from the RFID tag readers;   the software module further being configured to identify a semantic group of RFID tags by:
 issuing a first semantic group identification command to a first RFID tag; 
 conveying the group identification command from the first RFID tag to the second RFID tag via tag to tag communication; 
 issuing a second semantic group identification command; 
 receiving a response from at least one of the first RFID tag or second RFID tag; and 
 identifying a semantic group, the semantic group including the first and the second RFID tags based on the received response. 
   
     
     
         2 . The system of  claim 1  wherein the second RFID tag comprises an internal memory, and further wherein an indication of receiving the semantic group identification command is stored in the internal memory. 
     
     
         3 . The system of  claim 1  wherein further the first RFID tag comprises an internal memory, and further wherein a response to the semantic group identification command from the second RFID tag is stored in the internal memory. 
     
     
         4 . The system of  claim 1  wherein semantic rules are stored on at least one of the first and second RFID tags, and further wherein the step of identifying a semantic group is based on the stored semantic rules. 
     
     
         5 . A radio frequency identification (RFID) system for localizing at least a first RFID tag and a second RFID tag, the system comprising:
 a plurality of radio frequency identification (RFID) tag readers;   a computer in signal communication with the plurality of RFID tag readers over a network;   a memory associated with the computer, the memory storing a network model having a plurality of endpoints and oriented links between the endpoints, wherein the endpoints are associated with physical locations in space, each of the endpoints having associated with it one or more of the RFID tag readers;   the computer being configured to operate a software module that localizes the RFID tag based on data received from the RFID tag readers;   the software module further being configured to associate a group semantic attribute to at least one of the RFID tags by:
 associating a semantic attribute with the first RFID tag at a first time; 
 determining that the first RFID tag and the second RFID tag are present at a first location at a second time; 
 determining that the second RFID tag has disappeared from a semantic field within an interval of time from the second time; and 
 associating the group semantic attribute to the second RFID tag based on the semantic attribute associated with the first RFID tag. 
   
     
     
         6 . The system of  claim 5  wherein the step of associating the group semantic attribute to the second RFID tag is performed as a function of a determination that all tags associated with the group semantic attribute have disappeared from the semantic field. 
     
     
         7 . The system of  claim 6  wherein the first RFID tag and the second RFID tags comprise tag to tag communication capabilities and the determination that all tags associated with the group semantic attribute have disappeared from the semantic field is performed using tag to tag communication. 
     
     
         8 . The system of  claim 5  wherein the second RFID tag belongs to a first semantic group, and further wherein the software module is further configured to associate the group semantic attribute to the first semantic group. 
     
     
         9 . The system of  claim 5  wherein the first RFID tag and the second RFID tags comprise tag to tag communication capabilities, the step of associating the group semantic attribute being performed as a function of tag to tag communications. 
     
     
         10 . The system of  claim 5 , wherein the second RFID tag belongs to a first semantic group and the software module is further configured to associate the group semantic attribute to the first tag only if all RFID tags of the first semantic group have disappeared from the semantic field. 
     
     
         11 . The system of  claim 10 , wherein the first and second RFID tags include tag to tag communication capabilities and the system uses tag to tag communication to determine the disappearance of the first semantic group from the semantic field.