| 摘要 |
PROBLEM TO BE SOLVED: To provide a wireless positioning system enabling positioning over a wide range, independently of the directivities of the antennae. SOLUTION: A terminal to be positioned includes the antennae ANTa and ANTb arranged symmetrically, and the anisotropies of radiation patterns of the two antennas are symmetric. The terminal to be positioned transmits a first positioning packet from the antenna ANTa. When the first positioning packet is received by only base stations B and C, the information on the received time difference between the base stations B-C is found. Successively, the terminal to be positioned transmits a second positioning packet from the antenna ANTb. Data of the second positioning packet store information on the transmission time difference between the first positioning packet and the first positioning packet. When the base station A receives the second positioning packet, the time the first positioning packet will probably have reached the base station A is calculated from the information on the difference between the received time and the transmitted time of the second positioning packet. Information on the time difference received between the base stations A-B is also found. The position of the terminal to be positioned can be specified, based on the two time differences received. COPYRIGHT: (C)2008,JPO&INPIT
|
