中文摘要：

随着舰船隐身性能越来越受到重视，封闭式筒形桅杆因其雷达散射截面积小、隐身效果好而被广泛采用。图形电磁学（ GRECO）是求解舰船封闭式桅杆等高频电、大尺寸目标特性最有效的方法之一。提出了一种精确提取可见面元几何信息方法，得到了一种改进的GRECO算法，克服了传统GRECO算法无法精确提取像素法矢信息缺点。进而，采用AP/PO法，并对传统的多次散射面元对判别方法进行了适当改进，提高了计算效率。最后，利用改进的GRECO算法计算分析了英国45型驱逐舰的桅杆RCS分布，得到如下结论：对于封闭式桅杆来说，镜面散射是封闭式桅杆的主要散射源，良好的隐身设计可以有效地降低多次散射对桅杆整体RCS的影响。

英文摘要：

With the increased attention given to the stealth performance of ships, owing to their small cross section on dispersion of radar and excellent stealth effect, enclosed tubular masts have been widely adopted. GRECO （ graphical electromagnetic computing ） has been considered as one of the most efficient methods to acquire the characteristics of high-frequency and electrically large-sized targets such as masts. A new improvement of accurately extracting the geometric information of pixels has been presented, an improved GRECO algorithm has been presen-ted, which can overcome the traditional shortcomings of GRECO, as it is unable to accurately extract the normal vector of the target. Furthermore, the Area projection/Physical optics was used and the traditional discrimination method of facet pairs that might contribute to multiple scattering was improved suitably in order to improve the computational efficiency. Finally, the improved GRECO algorithm was used to calculate and analyze the RCS distribu-tion of the British Type 45 destroyer′s mast. The following conclusions were made： mirror scattering is the main scattering source of enclosed masts, and good stealth design can effectively reduce the influence of multiple scattering on the RCS of the whole mast.