| 摘要 |
<P>PROBLEM TO BE SOLVED: To eliminate an effect of a noise component in calculating a distance to a transmission antenna of a vehicle-mounted apparatus to obtain highly reliable distance data. <P>SOLUTION: A mobile device for a vehicle includes a receiving unit 20 for receiving each transmission signal transmitted from a plurality of transmission antennas ANT1 to ANT3 of the vehicle-mounted apparatus 2, a control unit 22 for calculating a distance to each of the transmission antennas ANT1 to ANT3 from a signal intensity of each received transmission signal, and a transmitting unit 21 for wirelessly transmitting the distance data as far as each of the transmission antennas ANT1 to ANT3 to the vehicle-mounted apparatus 2. During a period of having no communications with the vehicle-mounted apparatus 2, the signal intensity of a received signal is measured to store a measured value in a memory 24 as the noise component. The signal intensity of each transmission signal transmitted from each of the transmission antennas ANT1 to ANT3 is corrected with the noise component to obtain the distance when communicating with the vehicle-mounted apparatus 2. <P>COPYRIGHT: (C)2010,JPO&INPIT |
