| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide a radio device capable of improving its position determining accuracy without employing any complicated procedure for judging the position of a motor vehicle by using a means of mobile phone. <P>SOLUTION: A main unit 5 in a motor vehicle 3 has an LF transmitting antenna for transmitting a search signal. An LF transmitting antenna 15 includes five antennas installed to door knobs of the motor vehicle 3; and a mobile phone 4 receives search signals transmitted from antennas 21 to 25 constituting the LF transmitting antenna 15 and measures the field strength of the search signal received. The mobile phone 4 transmits field strength data expressing the field strength measured. The main unit 5 calculates a relative position information based on the field strength data for the motor vehicle 3 carrying the mobile phone 4. The main unit 5 controls the locking or unlocking of the relevant door for the motor vehicle 3 based on the relative position information of the motor vehicle. <P>COPYRIGHT: (C)2007,JPO&INPIT |
