| 摘要 |
<p>A transmission unit transmits an electric wave having a predetermined beam width in a vertical direction ahead of a vehicle. A reception unit receives a reflected wave from a target (a vehicle traveling ahead) of the electric wave transmitted from the transmission unit. A measurement unit measures the distance from the vehicle to the target on the basis of received electric power of the reflected wave received by the reception unit. A speedometer acquires the speed of the vehicle. When the speed of the vehicle acquired by the speedometer is a predetermined value or less and the distance from the vehicle to the target measured by the measurement unit is a predetermined value or less, a signal processing unit calculates the change curve shape of the electric power value with respect to the distance from the vehicle of the received electric power of the electric wave received by the reception unit, and determines, as a target to be detected, a portion of the change curve shape, the portion indicating the local maximum value or inflection value of the electric power value, the electric power difference of which from the maximum value of the electric power value is within a fixed range, among local maximum values or inflection values of the electric power value at distances closer to the vehicle than that corresponding to the maximum value.</p> |
