REDUCTION OF INSAR DEM TROPOSPHERIC NOISE WITH GPS OBSERVATIONS
Satellite Interferometric Synthetic Aperture Radar (InSAR) Signals are often intensively contaminated by atmospheric delays. The atmospheric conditions especially its water vapor content significantly varies in space and with time. Therefore, it is essential to characterize the atmospheric variations in order to mitigate these effects by appropriate means. In the topographic case, for high-resolution DEM generation, the errors may be decreased by choosing interferometric pairs with relatively long baselines, as the error magnitude is inversely dependent on the perpendicular component of the interferometer baseline. For InSAR DEM quality estimation against tropospheric corrected one, we use the GPS measurements to create the reference DEM in the region. The preliminary results show that the corrected DEM by the phase gradient method has the highest correlation with the ground-based observations and the InSAR DEM which is corrected by phase gradient stacking method for water vapor effect in the troposphere has the best accuracy, ranging from 0.07 ~ 5.81 m, while the InSAR original DEM has an accuracy of 0.29 ~ 14.62 m.