Department of Regional Water Studies
TERI School of Advanced Studies.
Ms. Rinki Deo has her basic educational background in Physics and specializes in remote sensing and GIS. She completed her PhD in Resources Engineering from CSRE, IIT Bombay. While pursuing PhD, she got the DAAD fellowship (16 months including 4 months German language course) to work at the prestigious German Aerospace Center (DLR), Germany for one year. In addition to her Ph.D. work which focuses on Evaluation of TanDEM-X Interferometric Digital Elevation Models, she was also involved in research work in various other fields such as SAR polarimetry, PSInSAR, SAR signal processing, Speckle filtering, etc. She has contributed in the development of software named TARANG which is being used by many users in India to process Radarsat-2, ALOS-2, TerraSAR-X and Indian RISAT-1 SAR data for various applications. She possesses the knowledge of interferometric SAR data processing using different softwares like SARscape, Doris and GAMMA and have gained considerable expertise in image processing and GIS softwares (ERDAS, ENVI, ArcGIS, etc) and in programming language like C and IDL.
Synthetic Aperture Radar (SAR): Principles and Applications The invention of the Synthetic Aperture Radar (SAR) principle represented a major breakthrough in the development of radar imaging systems. SAR has been widely used for earth remote sensing for the last three decades. This technology is unique in providing high resolution, day-and-night and weather independent images and has the capability of providing sub-surface information by penetrating through the target. It is one of the effective tools used to monitor dynamic processes on the Earth surface in a reliable, continuous and global way.
A SAR is an imaging radar mounted on a moving platform. The high technology data collection system along with advanced signal processing involved in SAR constructs a virtual aperture that is much longer than the physical antenna length and is thus capable of achieving fine resolution image using both short and long waves. These images represent the backscattered microwave energy, the characteristics of which depends on the physical (i.e., geometry, roughness) and electrical properties (i.e., permittivity) of the imaged object. These dependencies enable SAR image to be used in models of the scattering mechanism and quantify various characteristics of earth’s surface, such as topography, soil moisture, snow water content, etc. The widely used technology in this domain are SAR Interferometry, SAR Polarimetry, Polarimetric SAR interferometry and SAR Tomography. SAR interferometry technique compares the phase of two images acquired from two positions or at two different times and enables the enables the highly accurate measurement of important geophysical parameters such as surface topography, ground deformation and subsidence as well as glacier movements. SAR polarimetry measures the polarimetric properties of scatterers and from which several related qualitative and quantitative physical information for land, snow and ice, ocean and urban applications can be derived. Polarimetric SAR Interferometry (Pol- InSAR) technique represents the coherent combination of and allows the characterization of the vertical structure of natural and artificial volume scatterers. SAR tomography technique enables to retrieve the vertical distribution of scatterers. Various applications of SAR include topographic mapping, , geology and mining, oil spill monitoring, sea ice monitoring, geologic mapping, vegetation mapping, oceanography, agricultural classification and assessment, land use monitoring glaciology, and planetary/celestial investigations.
With the advancement in these SAR technologies over the past decades we have now entered into the golden age of SAR and the upcoming highly innovative concepts foresees the exciting future of SAR remote sensing making possible the continuous observation of Earth’s dynamic processes with much better quality and resolution.