| 摘要 |
PROBLEM TO BE SOLVED: To transmit beacon information to a moving body at a stop and to improve radio wave radiation efficiency without providing a means which switches zone information with time by rotating a couple of antennas which feed a signal, generated by superposing the zone information on transmit information, in different main radiation directions. SOLUTION: The antennas 1 and 2 are rotated normally and reversely by a rotating means 4 and installed in a parking lot or at a parking lot end at a ground height of several to tens of m. Further, they are installed having specific elevation angles and radiate radio waves B to different partial areas. The antennas 1 and 2 are rotated in horizontal plane by the rotating means 4 to provide information for a vehicle at a stop. An on-vehicle device at a stop detects variation of the zone information when receiving a radio wave, so received information can be displayed by transmitting information of a normal direction or information of both the directions as transmit information. |
