Design of Polarimetric Synthetic Aperture Radar for Venus: A Proposal

Understanding the surface composition and conditions on Venus is beneficial for improving our understanding of the origin and evolution of terrestrial planets and characteristics of exoplanets. Microwave remote sensing with SAR can be used to image the surface of Venus through a dense optically opaque atmosphere. Synthetic Aperture Radar (SAR) on the Magellan mission mapped the surface of Venus with a coarse resolution in single polarization band. In this paper, we propose a full-polarimetric synthetic aperture radar (PolSAR) to map the surface of Venus with high resolution of 40m. This PolSAR will provide complementary information than SARs on other contemporary mission proposals such as NASA's VISAR and ESA's VenSAR since it will be the only one providing polarimetry . The design goals of sensitivity of -25 dB at incidence angle range of 31.1-32.7 deg were obtained by simulating angular response of backscaterring coefficient for Venusian surface model. The design of this SAR is carried out both an elliptical orbit (200 km X 600 km) as well as a circular orbit (350km altitude) by performing trade-off studies between parameters like power, frequency, noise equivalent sigma naught, pulse repetition frequency(PRF), altitude, look angle, pulse width, swath, and radar ambiguities. The PolSAR design aims at deriving the physical characteristics of the Venusian surface by polarimetric decomposition which will resolve the gap areas in Venusian surface studies.