Imaging Geodesy—Centimeter-Level Ranging Accuracy With TerraSAR-X: An Update

In this letter, we report on two major improvements with respect to the results presented in our recent paper on imaging geodesy: the atmospheric delay estimation using numerical weather model data and the continental drift adjustment from different geodetic coordinate systems. First, we demonstrate that the GPS-based zenith delay estimates used in our recent paper to correct synthetic aperture radar (SAR) data can be replaced by estimates calculated from numerical weather model data. This leads to a much wider applicability of our approach and even improves the accuracy from 3.8 cm to 3.2 cm. Second, for measuring the absolute position within the SAR image, the coordinate system used has to be carefully chosen, otherwise continental drift affects the results. We show that correct consideration of the reference frames eliminates residual offsets by up to 3.1 cm.