Fast shadowing test algorithm based on target division by cubes

Physical optics (PO) is an efficient method in calculation of complex electrically large object's (CELO) radar cross section (RCS). According to PO's assumptions, only the illuminated part of the target has contributions to electromagnetic scattering. This paper represents a novel method that covers the target by overlapped cubes which separate the facets to several consistent groups. To make sure every facet is contained in at least one cube, the cubes might have common domain and some facets in the domain are included in more than one cube. Cubes’ shadowing tests are conducted before facets’ tests. If the cube does not shadow the point to be tested, then it means that all of the facets within the cube cannot shadow the point and they needn't more test. Otherwise, every facet within the cube should be tested whether or not shadowing the point. Through this process, much time in shadowing tests is saved. Computation experiment validates the accuracy and efficiency of the algorithm. This paper also discussed the influence of the cubes’ size on performance of the algorithm. If proper parameters are chosen, the time saved can be up to 90%.