| 摘要 |
<P>PROBLEM TO BE SOLVED: To achieve an anti-theft system without providing a new structure, by using a TPMS (a direct tire air pressure monitoring system). <P>SOLUTION: A receiving device 10 carries out normal operation in the TPMS, namely operation receiving tire air pressure data sent from each transmitting unit 20 by radio and judging the presence/absence of air pressure abnormality, or operation detecting an RSST of a radio signal by a radio receiving circuit 15. Furthermore, a processor 11 memorizes a change history of the RSSI (electric field strength; electric wave strength) in a memory 12. The presence/absence of theft action and action before theft is judged on the basis of the change history. <P>COPYRIGHT: (C)2007,JPO&INPIT |
