Slope Correction Of Sentinel-1 SAR Data using Physical Model of Terrain - Wave Interaction

SAR (Synthetic Aperture Radar) is an active remote sensing technology using microwave, so that can operate all day and can penetrate even in cloudiness. However SAR data can be difficult to interpret especially because of slope effects. In the hilly area, the standard calibration i.e. radiometric calibration of SAR data is inadequate to get a data with good consistency. There are some additional errors due to differences in slope in non flat area. in the homogeneous land cover, the backscatter should be equal, but in non flat area it can be varies depending on slope relatively. Thus, it is advisable to apply some slope correction first before the utilization of the data. Applying a slope correction, the backscatter intensity corrected in order to equal the backscatter. This research applied o slope correction based on a simple physical of the terrain-wave interaction model into a Sentinel-1 data. The model describes terrain as uniform opaque volume of isotropic scatterers, which is independent of terrain type, frequency and polarization. The correction consider the effects of the slope variation that influence backscatter intensity for each pixel data. Two acquisitions of Sentinel-1 C-SAR (C-band Synthetic Aperture Radar) of south Sumatera data used in this research. One is Sentinel-1 C-SAR data with ascending pass, VV — polarization acquired on december 16th 2014 and the other is descending pass, VV & VH — polarizations acquired on december 24th 2014. Experiment results show in the homogeneous land cover with varioted slope up to 47°, a decreasing amplitudo for slope effects ie. 1.5 dB was obtained. This improvement can also assest visuoly by combining ascending and descending data then analyze the shifting intensity.