BISTATIC ISAR IMAGES FROM A TIME-DOMAIN CODE

Inverse-synthetic-aperture-radar (ISAR) images of radar targets are useful for target identification, visualization, and the analysis of scattering centers. The major advantage of bistatic over monostatic-ISAR imaging is the reduction, in the number of computed incident angles, from hundreds to one. This advantage has already been demonstrated for a Physical Theory of Diffraction (PTD) code, XPATCH. The bistatic-imaging technique can be extended to scattering data obtained from any time-accurate or iterative method, including low-frequency algorithms. This paper presents images from data obtained with a finite-volume time-domain (FVTD) code. It also provides relations between (I),the range and resolution of the bistatic scattering data in the Fourier domain, and (2) the pixel resolution and image extent in the physical domain for the down-range and cross-range directions. A tapering function is applied in the Fourier domain, to dampen ringing effects. Results are shown for a trapezoidal plate, a cone-sphere, and a square-aperture cavity.