METHOD AND APPARATUS FOR LOCALIZATION OF RFID TAGS

摘要

A method and apparatus for an RFID tag to facilitate the determination of its location while at the same time minimizing the energy drain on the tag's battery (306). At predetermined intervals, the tag transmits its identifier along with status information (302). If the status indicates that the tag is in a new location (304), the tag will then expend additional battery energy by participating in the determination of its location (306). The distance from an interrogator to the tag is determined by transmitting two signals from the interrogator that propagate at different velocities (602/604). By determining the difference in arrival times at the tag of the two signals, the distance from the interrogator to the tag can be determined (606).