Study of Hybrid Polarimetric Parameters generated from RISAT-1 SAR data for various Land Cover targets (original) (raw)

Hybrid polarimetric synthetic aperture radar (SAR) is having enormous advantages over linear polarimetric like self-calibration, low susceptibility to noise, higher incident angle range coverage, larger swath coverage and lower rotational sensitivity of the target. This makes researchers interested to study the hybrid polarimetric SAR data for various remote sensing applications. In this paper, backscatter signals and scattering decomposition from hybrid polarimetric Radar Imaging Satellite-1 (RISAT-1) SAR data for various land cover targets have been studied. Even though SAR transmits right circular polarized signal, the return RADAR signal may be partially polarized (which means sum of completely polarized and un-polarized signal). The RADAR return signal and scattering decomposition varies for different land cover targets depending on the geometrical, structural and electrical properties of the target under consideration. Here, Stokes classical parameters are used to study the RADAR return signal. m-δ and m-χ space decomposition are used to study the scattering mechanism. Signature study of polarimetric parameters has also been carried out to understand scattering mechanism in terms of even bounce, odd bounce and volume component. It is observed that depolarization effect is more sensitive for vegetation whereas the backscatter signal strength is low from surface water bodies due to specular reflection. It is also observed that volume scattering component is similar in both the decompositions. However, even bounce is over estimated in m-χ as compared to m-δ decomposition for all the land cover targets like water, forest, sugarcane, wheat, fallow, dry river bed and built-up.