Radar Cross Section of Fishing Training Ship NANSEI-MARU

In radar navigation, it is very important to get an accurate radar image of other ships in order to avoid collisions between ships. However, when meteorological and maritime conditions are bad, or when the aspect angle of a small ship changes, it may become difficult to obtain a radar image of the small ship. Therefore, safe navigation is not assured. So, the measurement of a radar cross section of Nansei-maru was carried out. The results obtained in this study were as follows : 1. A refracting point between 1/R^4 and 1/R^8 attenuation curves existed at 3945m. 2. The effective height of radar wave reflection was measured at 2.46m from the surface of the sea. 3. The radar cross section was largest, 1790m^2, when the beam faced the radar antenna, and was smallest, 130m^2, when the bow was toward the antenna. The value decreased about 10 dB, when it shifted at 30° from the beam direction. In addition, the value of the stern direction was larger than that of the bow direction