A Quantitative Assessment of The ETAD Data Capability of Filtering Out Atmospheric Phase Screen from DInSAR Products Generated at Medium/Full Spatial Resolution

The Extended Timing Annotation Dataset (ETAD) product consists of a set of correction layers to improve the range and azimuth timing of Sentinel-1 (S1) Synthetic Aperture Radar (SAR) images. Moreover, the ETAD layers also allow the mitigation of the Atmospheric Phase Screen (APS) component which may affect the Interferometric SAR products. In this paper, we present a detailed experimental analysis to investigate the effectiveness of the S1 ETAD correction layers in removing the APS component from Differential Synthetic Aperture Radar (DInSAR) products (interferograms and deformation time series).In particular, the performance analysis of the ETAD APS correction has been carried out by exploiting the Parallel Small Baseline Subset (P-SBAS) approach to process a large dataset of 104 S1 images acquired along ascending orbits during the 2018-2020 time span over Central/Southern Italy. Several statistical metrics have been then applied both to the 278 generated interferograms and to the P-SBAS deformation time series, produced at medium spatial resolution (about 40 m), to quantitatively investigate the validity of the ETAD APS correction.