| 摘要 |
<p>The invention relates to an ASDE radar to supply information on airport surface traffic. A well-known ASDE radar comprises an antenna having an elevation-depending gain factor <IMAGE> for omega 1</= omega < omega 2, where omega 1, omega and omega 2 represent angles of depression. In such a radar, the echo power of an airport surface target is independent of the distance, whereas the echo power of rain clutter is inversely proportional to the square of the distance. Consequently, a remote surface target still projected on the radar screen above the rain clutter, is likely to disappear in the rain clutter when approaching the radar; this may result in fatal consequences. To solve the above problem, the ASDE radar of the invention comprises a combination of an antenna having a gain factor <IMAGE> and a sensitivity time control circuit in its receiver.</p> |
