A Hybrid Algorithm for Radar Cross Section Calculation of Electrically Large Targets

In our previous study, we proposed the bidirectional analytical ray tracing (BART). BART is based on geometrical optics (GO) and physical optics (PO) to calculate the multiple reflections of electromagnetic waves by dividing the target into many small facets, which can calculate the radar cross section (RCS) of electrically large targets quickly. However, GO can only calculate the contribution of incident and reflected field, and cannot solve the diffraction problem such as edge and vertex, which makes the calculation results of BART inaccurate under some angles. The uniform geometrical theory of diffraction (UTD) can compensate for the shortcomings of GO to overcome the failure in the shadow area and the discontinuity at the boundary between shadow area and bright area. A hybrid algorithm combining the BART and UTD is proposed in this paper. UTD is introduced into the BART to solve the problem that there is no electric field in the shadow area and discontinuity at the boundary. While ensuring calculation efficiency, it improves the accuracy of BART in calculating the RCS of electrically large targets.