| 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 , for .omega.1<.omega.<.omega.2, where .omega.1, .omega. and .omega.2 represent angles of depression. In case of the above 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 incur fatal consequences. To solve the above problem, the ASDE radar of the invention comprises a combination of an antenna having a gain factor , and a sensitivity time control circuit in its receiver.</p> |
