Airborne Circularly Polarized Synthetic Aperture Radar

In this article, airborne broadband (maximum 400 MHz bandwidth) C-band circularly polarized synthetic aperture radar (SAR) is proposed and developed for further study on airborne compact polarized synthetic aperture radar (CP SAR) system using circular polarization. This article explains the scattering characteristic of circular polarization as the concept of circularly polarized SAR, system configuration, RF system and antenna, ground test, and flight test of circularly polarized SAR in Hinotori-C2 (Firebird-C2) mission onboard CN235MPA aircraft on 14 and 15 March 2018 at South Celebes, Indonesia. The result of the flight test depicts multipath full polarimetric circularly polarized images that show good performance of circularly polarized SAR and matched well to the result of the ground test of a multipolarized single pulse. The circularly polarized scattering clarification using trihedral, cylindrical, and omni corner reflectors (TCR, CCR, and OCR), assessment of circularly polarized image analysis, and image classification using the conventional axial ratio (AR), ellipticity (ε), and polarization ratio (ρ) are discussed. The proposed circularly polarized SAR will enrich the existing CP SAR systems and could be employed in further study of CP SAR calibration technique, also applications development for the environment and disaster monitoring using CP SAR.