Eibert, “Bistatic image formation from shooting and bouncing rays simulated current distributions

Abstract—Inverse Synthetic Aperture Radar (ISAR) imaging is one of the most sophisticated methods to obtain information about the scattering or radiation properties of a finite sized object. The idea is to process the scattered or radiated fields coherently over a certain frequency bandwidth and over a certain angular range in order to generate the image. In a simulation based approach, this procedure can be considerably simplified, if the source currents are known (either real or equivalent) and if a bistatic image is desired. By inserting the radiation integral into the imaging integral and by interchanging the integration orders, the imaging point spread function can be generated and the image formation is reduced to a convolution of the point spread function with the current distribution. A concise formulation of this well-known methodology is presented together with a discussion of important properties. Various examples of 2D and 3D images for complex metallic objects such as automobiles are shown, which have been obtained from the surface currents of a Shooting and Bouncing Rays (SBR) field solver. 1