| 摘要 |
<p>PROBLEM TO BE SOLVED: To efficiently and surely detect, for example, an obstacle within a specific height range by applying beams being stopped down by a fixed antenna and performing horizontal scanning by rotating a reflection plate. SOLUTION: The reflection plate 12 is mounted rotatably at a certain angle by a rotary shaft 11 that is provided at its central part and rotates by a drive mechanism between a position being indicated as the reflection plate 12 and a position being indicated as a reflection plate 12'. When the reflection plate 12 is located at the position of the reflection plate 12 due to the rotation, incidence beams B1 from an antenna 10 are emitted in the direction of radiation beams BO. When the reflection plate 12 is located at the position of the reflection plate 12', beams are emitted in the direction of radiation beams BO' and a reflection plate horizontal section is on a straight line, so that the beam width does not change in horizontal direction. A rotary angle at the position of the reflection plate 12' is set toψ+γ. However, the angleγof beams can be selected within a range where the radiation beam BO' cannot be applied to the antenna 10. By stopping down the beam width of incidence beams from the antenna 10, a search accuracy in the horizontal direction can be improved.</p> |
