| 摘要 |
PROBLEM TO BE SOLVED: To constantly and accurately detect intrusion while coping with variation in an output state of ultrasound wave emission means T due to age deterioration.SOLUTION: An ultrasound wave is emitted into a cabin from the ultrasound emission means T, while an ultrasound wave reflected in the cabin is received by ultrasound detection means R. The ultrasound wave emission is composed of a main beam M propagating toward a rear side and a side robe SR propagating toward a driver seat door 25. According to receiving intensity difference of the ultrasound receiving means R between when the driver seat door 25 is opened and when it is closed, an output state of the ultrasound emission means T is corrected (for example, frequency correction). |
