基于改进的GO-PO混合方法的舰船与海面复合电磁散射研究

Study on the Composite EM Scattering from Sea Surface with Ship Based on an Improved GO-PO Hybrid Method

为了提高几何光学与物理光学(GO-PO)方法在计算舰船目标散射、海面与舰船目标耦合散射时面元对入射波和反射波可见性判断的效率,提出了Kd-tree和GO-PO方法相结合的模型.Kd-tree方法在入射波或反射波射线与面元相交测试前,首先执行射线与面元所在包围盒的相交测试,若包围盒的距离参数不符合要求,则无须进入该包围盒,减少射线与大部分面元不必要的相交测试.数值结果表明,改进的GO-PO混合方法在保证计算精度的同时能够提高效率约3倍.因此,该混合方法是相对有效且能够运用于大范围海面与大型舰船目标复合电磁散射特性的研究.

In order to improve the efficiency of the geometrical optics and physical optics(GO-PO)method in testing the visibility of patches to the incident and reflected waves in the calculation of the scattering of ship target and coupling scattering between sea surface and ship target,a model combined with the Kd-tree and GO-PO method is presented.The Kd-tree method firstly carries out the intersection test between the ray and the bounding box where the patch is located before the intersection test between the incident wave or reflected wave ray and the patch.If the distance parameters of the bounding box do not meet the requirement,the ray is not necessary to enter the bounding box,which can reduce the needless intersection tests.The numerical results show that the improved GO-PO hybrid method could improve the efficiency about three times on the premise of guaranteeing the computational accuracy.Therefore,the hybrid method is relatively effective and can be applied to the study on the composite EM scattering characteristics of electrically large sea surface with a ship target.