Geodetic SAR Positioning with TerraSAR-X and with Sentinel-1

Abstract

Geodetic SAR Positioning with TerraSAR-X and Sentinel-1 We report from very successful experiments conducted during the recent years with a radar corner reflector at the geodetic observatory in Wettzell, Germany, where we achieved a one centimeter (absolute) range pixel localization accuracy. The overall localization error can only be reduced from decimeters to one centimeter with our developed compensation methods which include the correction of dry and wet atmospheric delays, ionospheric total electron content, solid earth tides, continental drift, atmospheric pressure loading and ocean tidal loading. With this high accuracy available, absolute pixel localization or speckle/feature tracking can be used as an interesting and powerful alternative to InSAR. The advantages are that 2D information can be retrieved (InSAR only 1D), absolute positions and displacements can be retrieved (no reference point required) and that the method is very robust since phase unwrapping is not required. The accuracy in real world applications is limited by the pixel resolution, the object contrast and the coherence. Our presentation gives an overview of monitoring results of a radar reflector over more than one year. Furthermore we report on the used methods for geodetic correction. Finally, we give first examples of real world applications and predict the feasibility of our developed techniques for Sentinel-1.