Radar Reflection Characteristics of Small Grass-Fiber Reinforced Plastic Ship

摘要

When the AIS (Automatic Identification System) begin to be generally used in the near future, it is important to use the radar to detect the small ship like a pleasure boat. But the radar cross section of the small ship made from FRP (glass-fiber reinforced plastic) is small, and it seems to be difficult for radar to detect such small ships made from FRP. Especially, under conditions of poor visibility such as night, a foggy day and so on, the small ship becomes a very dangerous target. Therefore a research is required to detect such smalls ship when they are in sufficient safe distance. Then, in order to measure quantitatively the radar reflection characteristics of the small FRP ship with the length of 9m we carried out a detailed experiment at sea using Radar Echo Recording System. This paper describes analysis of the maximum received signal intensity and the radar cross section of the small ship. It was confirmed that the small FRP ship could be detected when we kept continuous watching on by the radar from the sufficiently safe distance. On the other hand, the reflection level of the moving small ship changed considerably every scan of the radar antenna, and the radar echo of a small ship often disappeared from the radar display when the received reflection level was below setting sensitivity.