| 摘要 |
<p><P>PROBLEM TO BE SOLVED: To provide an apparatus for detecting the azimuth of a wireless terminal, which can perform accurate azimuth detection without reducing a detection distance. <P>SOLUTION: During a period of successively changing the directivity of a variable directivity antenna 10 within an azimuth detection range, a first RSSI is successively stored in a buffer 271 (S4). A point of time that reception completion of tag data is determined is set as a period end point of time, a period which is a signal transmission period in which a radio tag 10 transmits signals retroactively to the period end point and in which the directivity of the variable directivity antenna 210 is changed one by one over the whole azimuth detection range is determined as a data entry period, and the first RSSI in the data entry period is acquired from the buffer 271 (S6). Since the period of acquiring the first RSSI is based on the reception completion point and the determination of reception completion is not performed by signal intensity, the determination is not easily influenced by noise. Since azimuth detection is possible after determining reception completion, a detection available distance also can be secured. <P>COPYRIGHT: (C)2012,JPO&INPIT</p> |
