ISAR Tomography for Full-Polarimetric 3-D Radar Cross-Section Measurements

Radar cross-section (RCS) images are valuable for understanding the 3-D target scattering center distribution of objects. However, 3-D RCS imaging requires more complex measurement systems and much more data points compared to conventional 2-D methods. A reduction of measurement effort can be achieved by using a tomographic technique based on amplitude-phase-spectrum estimation, scale-invariant feature transform image registration, and constant false alarm rate detection. Besides an amplitude spectrum, the proposed method also obtains the phase spectrum of the scattering center distribution, which allows the application of polarimetric decompositions. The generation of full-polarimetric 3-D images is demonstrated based on measurement data obtained in a compact antenna test range. Since all relevant scattering mechanisms can be identified, the approach proved to be useful for an advanced understanding of the scattering mechanisms occuring at radar targets.