Fast Solution of Scattering From Moving Target by Dynamic-Octree-Based SBR Algorithm

Abstract

This letter proposes a shooting and bouncing ray (SBR) method based on a dynamic octree structure to accelerate the solution of scattering from a moving target. In this algorithm, three coordinate systems are established, i.e., the world coordinate system (WCS), the local coordinate system (LCS), and the perspective projection coordinate system (PPCS). First, an octree structure is created to store the target facets in the LCS that moves with the target in the WCS. The octree remains relatively stationary with the target, which avoids rebuilding the structure at every moment. Second, to accelerate the shadow elimination, the scanline algorithm is used to convert the 3-D processing into a 2-D graphic display in the PPCS. Third, high-order ray tracing is completed in the LCS. A forward–backward ray-tracing technology is adopted to guarantee the precision of the illuminated facet identification. Finally, the information of illuminated facets is transferred from the LCS to the WCS, and the scattering of target is calculated in the WCS. Meanwhile, some numerical simulations of our method are compared with those of the FEKO-MLFMM and the traditional octree-SBR method. The results show that the proposed method greatly reduces the computation time while maintaining satisfactory accuracy.