| 摘要 |
<P>PROBLEM TO BE SOLVED: To reduce a size of a node, and to attain a low electric power consumption. <P>SOLUTION: The node 01 is provided with a function for transmitting a radio signal (positioning signal) 05 for measuring a position. A reference station 02 is provided with a function for transmitting a radio signal (reference signal) 06 for determining a reference time after receiving the signal from the node 01. Each access point (AP) 03 is provided with a function for measuring reception times of the positioning signal 05 transmitted from the node 01 and the reference signal 06 transmitted from the reference station 02. A position calculation server 04 is provided with a database (not shown in Fig.) including information about coordinates of the each access point 03 and a distance from the each access point 03 to the reference station 02, and is connected to the each access point 03 via a network 08. The position calculation server 04 calculates a position of the node 01, using a measured result acquired from the each access point 03 via the network 08, and the information included in the database. <P>COPYRIGHT: (C)2005,JPO&NCIPI |
