Patent ID: 7573418
Filing Date: 2009-08-11
Classification: G01S,G06K

Abstract:
1. An apparatus configured to communicate with an RFID (Radio Frequency Identification) tag through a radio wave, said apparatus comprising: a plurality of antenna elements, each of which is configured to receive the radio wave from the RFID tag; a direction estimating section configured to estimate an incoming direction of the radio wave from the RFID tag at each of the antenna elements thereby obtaining estimated directions; a power measuring section configured to measure a power of the radio wave received by each of the antenna elements, thereby obtaining a measured power ratio; a position calculating section configured to calculate a position of the RFID tag based on the estimated directions; and a power ratio estimating section configured to estimate a ratio of powers to be received by the antenna elements based on the calculated position of the RFID tag, as an estimated power ratio; wherein the position calculating section is configured to compare the measured power ratio with the estimated power ratio to verify the calculated position of the RFID tag.