| 摘要 |
<p><P>PROBLEM TO BE SOLVED: To reliably determine reductions in the sensitivity of an object detection means even when the detection frequency of objects is low. <P>SOLUTION: The object detection means M1 transmits electromagnetic waves from transmission means 1 and 2 to a prescribed region, and a distance detection means 5 detects at least the distance to an object on the basis of results of the reception of electromagnetic waves at reception means 3 and 4 after reflection at the object. Since an anomaly determination means M2 determines that the object detection means M1 is anomalous when the difference between a maximum value and a minimum value of a reception level of electromagnetic waves received by the reception means 3 and 4 is less than a predetermined threshold within a prescribe time (for example, three minutes) timed by a timing means M3, it is possible to accurately determine anomalies even when one is traveling on a road in a desert in which there is scarcely any object to be detected. <P>COPYRIGHT: (C)2006,JPO&NCIPI</p> |
