DETERMINATION OF TOPOGRAPHIC ELEVATIONS USING SAR INTERFEROMETRY AND GPS DATA

Abstract

An approach of microwave remote sensing with Synthetic Aperture Radar (SAR) Interferometry is a helpful technique for the quantitative assessment of topography of earth surface. kis now gaining increasing acceptance as a space borne technique for rapid and potentially accurate determination of topographic information. SAR Interferometry is one of the most efficient techniques for generation of Digital Elevation Models (DEMs) with high spatial and height resolution under all weather conditions. This technique is cost effective compared to ground survey and stereo viewing techniques. DEMs and the products derived from them are being used widely for numerous applications by the geoscientific community. Over the last few years SAR Interferometry has become a promising technique for various applications like topographic mapping, digital elevation modeling, monitoring seismic events, etc. The present study deals with the determination of elevations topography of Mumbai through the generation of digital elevation model of Mumbai using SAR Interferometric technique and to compare the SAR heights with the GPS heights. In SAR Interferometry phase content of the SAR images is an important parameter, using which, three-dimensional topographic information can be derived. In this technique the phases of the two images covering the same area and having different looking geometry are made to interfere to generate the interference fringes (Interferogram). The phase content in the information is related to the topography of the terrain. In this study GAMMA software has been used to process the interferometric data and consequently to generate the DEM. The accuracy of the interferometric method has been checked by comparing the SAR heights with the Global Position System (GPS) heights and heights of bench marks given in topographical maps and some building heights have been checked in Mumbai area and 3-D images have been generated.