Patent ID: 8207820

Claim:
A method comprising: transmitting, by an RFID tag reader, a first request for locating a first passive RFID tag in a first facility; receiving, by said RFID tag reader from a first group of active RFID tags in response to said first request, a first date/time associated with first data, wherein said first group of active RFID tags are located in said first facility; receiving, by said RFID tag reader from a second group of active RFID tags in response to said first request, a second date/time associated with second data, wherein said second group of active RFID tags are located in said first facility; determining, by said RFID tag reader, that said first date/time comprises an earlier date/time than said second date/time with respect to a current date/time; transmitting, by said RFID tag reader to said second group of active RFID tags in response to said determining that said first date/time comprises an earlier date/time than said second date/time, a second request for retrieving said second data, wherein said second data comprises an ID for said first passive RFID tag and distances between each active RFID tag of said second group and said first passive RFID tag; receiving, by said RFID tag reader from said second group of active RFID tags, said second data; receiving, by said RFID tag reader from a computing system, a map of said facility and first locations on said map for said second group of active RFID tags; determining, by said RFID tag reader, a first location within said facility for said first passive RFID tag, wherein said determining said first location is based on said second data, said map of said facility, and said first locations on said map for said second group of active RFID tags; and transmitting, by said RFID tag reader to a user, said first location.