Methode de correction des effets tropospheriques en interferometrie differentielle multi date

We present here the correction of tropospheric effects in order to improve punctual deformation mesurements when a dataset of multi-temporal interferograms is available. This method proceeds in two main steps. The first step is the estimation of global tropospheric effects. This is done two phases: First, a subset of very coherent pixels is identified using correlation between the phase value and topography. These pixels allow the computation of a global tropospheric model for each interferogram. Secondly, a cross validation of the models is applied using the entire multi-temporal database. Since multiple interferograms are available, a method can be conceived for the validation of tropospheric models using triplet of interferometric pairs containing one common acquisition. Indeed, it can be shown that an algebric relationship between parameters of the tropospheric models exists. The second step is the estimation of local tropospheric effects. We improve by the way a methodology based on correlation between interferograms containing one common acquisition. The modeled tropospheric effects are then removed from each interferogram. This technique was tested on a database of 81 differential interferograms of the Gulf of Corinth and used to improve the measurement of the ground deformation compared to GPS mesurements.