| 摘要 |
<p><P>PROBLEM TO BE SOLVED: To detect effectively an obstacle in various traveling states. <P>SOLUTION: An oscillator 10 outputs an oscillation signal both in FM-CW mode and in CW mode, and transmits a radio wave by switching between a wide-angle transmission antenna 16a and a narrow-angle transmission antenna 16b by a switch 14. A transmitted wave hits the obstacle and is reflected thereby, and then received by a receiving antenna. A received signal acquired by the receiving antenna 20 is mixed with the transmitted wave by a mixer 22, and the acquired difference signal is filtered by a filter 24 to acquire a beat signal. The distance and the speed of the obstacle are detected by a signal processing circuit 26 based on the beat signal. Then, a control circuit 30 switches adaptively two kinds of modes and two kinds of transmission antennas 16a, 16b, and performs effective obstacle detection in various states. <P>COPYRIGHT: (C)2007,JPO&INPIT</p> |
