Technical Papers and Presentations

Radar cross section (RCS) estimation of electrically large structures has been always an important research area. RCS approximation of a military platform is very crucial, for electronic warfare applications. Therefore, the need for simulating the RCS of complex shapes is essential since it is practical, cost effective, faster and more reliable, than constructing a RCS measurement setup. RCS is a significant parameter for the design of missiles, fighter aircraft, helicopters, launchers, ground military vehicles and other important structures, therefore it is necessary to evaluate the RCS of complex targets as it is the main design consideration. An in-house code is developed indigenously based on high frequency method to estimate the RCS of complex shape including aircraft.

This document deals with the monostatic RCS computation using Physical Optics (PO). PO method provides an enhanced solution for high frequency estimation of electrically large targets [1]. RCS estimation from PO method depends on the surface mesh of the target. Each triangular mesh element is known as facet. Since PO approach is a current based method [2], is used to estimate the current for those facets which is illuminated to the source plane. The current in which, facets are not directly illuminated to the source plane is considered to be zero. The scattered current is deployed in the radiation integral to estimate the scattered fields far as of target [3]. The triangular mesh elements are used to find the surface current and Taylor series is used to determine the scattered field of the target.

RCS has been estimated for the fighter aircraft by an in-house developed RCS estimation code namely “SPARCS” software. A parametric study of the software is done by considering different mesh size. Meshing splits, a continuous structure into distinct geometric parts. Meshing can be performed based on surface meshing (triangular element meshing, quadrilateral element meshing) and solid meshing (tetrahedral element meshing, pyramid element meshing, prism element meshing, hexahedral meshing). As the meshing size decreases, the number of meshing elements increases which results in better approximation. The triangular facets of the target have been considered as the input for RCS calculation. The triangular mesh elements are generated from the COMSOL Multiphysics® software. The RCS of fighter aircraft is analyzed by considering different mesh sizes as shown in Fig. 1. The finest mesh elements in the higher angle of incidence provide high accuracy in RCS estimation where, the radar can see the complex part of aircraft at high frequency.