| 摘要 |
PROBLEM TO BE SOLVED: To properly perform electronic authentication when an authentication device 20 for vehicle provided in a vehicle 10 communicates with a portable machine 40 carried by a user using an ultrasonic wave.SOLUTION: An authentication device 20 for vehicle includes a transmission and reception part 24 which transmits and receives an ultrasonic signal. A portable machine 40 includes a transmission and reception part 42 which transmits and receives the ultrasonic signal. The authentication device 20 for vehicle transmits the ultrasonic signal using the transmission and reception part 24. The portable machine 40 receives the ultrasonic signal and transmits the ultrasonic signal according to the reception. The authentication device 20 for vehicle receives the ultrasonic signal transmitted from the portable machine 40, performs electronic authentication according to the reception, and when authentication to the effect that the portable machine 40 is authenticated is performed, permits startup of an engine. The authentication device 20 for vehicle reduces output intensity of the ultrasonic signal when a door 12 and a window 14 are not closed. |
