Patent ID: 8816821

Claim:
A tag associating method of associating RFID tags belonging to a tag group, and a representative RFID tag ranked as a representative of the tag group; the associating method comprising: partially overlapping a communication area of a first antenna to read out data from the representative RFID tag and a communication area of a second antenna to read out data from said each RFID tag of the tag group; reading out data from said each RFID tag of the tag group by the second antenna while the first antenna reads out data a plurality of times from the representative RFID tag; making the data read out from the representative RFID tag and the data read out from said each RFID tag of the tag group into a pair of associated data; wherein reading by the first antenna is temporarily interrupted if the readout number of times of said representative RFID tag has reached a first defined number, followed by collective read out by the second antenna; resuming said read out by the first antenna, terminating said read out by the first antenna if the read out number of times of said representative RFID tag has reached a second defined number different from the first defined number, estimating a moving direction of the representative RFID tag; wherein an attribute of said representative RFID tag is used as an attribute of said each RFID tag belonging to the tag group when said each RFID tag belonging to the tag group and the representative RFID tag are associated with each other; and wherein information of the moving direction of the representative RFID tag, which is the attribute of the representative RFID tag, is used as information of a moving direction of said each RFID tag of the tag group, which is the attribute of said each RFID tag belonging to the tag group.