| US 7,573,418 B2 | ||
| Tag communication apparatus, control method for tag communication apparatus, computer readable medium for tag communication control and tag communication control system | ||
| Takehiro Kawai, Kyoto (Japan); Keisuke Saito, Kyoto (Japan); and Shinichiro Okamura, Kyoto (Japan) | ||
| Assigned to Omron Corporation, Kyoto-Shi (Japan) | ||
| Filed on Jun. 20, 2005, as Appl. No. 11/155,776. | ||
| Claims priority of application No. 2004-184094 (JP), filed on Jun. 22, 2004. | ||
| Prior Publication US 2005/0280538 A1, Dec. 22, 2005 | ||
| Int. Cl. G01S 13/74 (2006.01); G01S 13/08 (2006.01); G08B 13/14 (2006.01); H04M 1/00 (2006.01) | ||
| U.S. Cl. 342—42 [342/126; 340/572.1; 455/562.1] | 9 Claims |
| 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.
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