Sentinel-1 SAR system and mission

The paper provides an overview of the Copernicus Sentinel-1 mission, which includes Sentinel-1A (S-1A) and Sentinel-1B (S-1B) satellites, and the characteristics of its SAR system. Sentinel-1 uses pre-programmed SAR mode operations to provide a high revisit frequency and systematic global SAR image coverage. This is mainly based upon the operational use of the novel TOPS (Terrain Observation with Progressive Scans in azimuth) SAR imaging mode. In particular, we present results of the SAR system performance analysis focusing on the instrument stability and the achieved radiometric accuracy, as well as the Noise Equivalent Sigma Zero (NESZ). In addition, we discuss the cross-S-1A/S-1B SAR Interferometry (InSAR) performance considering the effects of burst synchronization and SAR antenna pointing on the achievable common Doppler bandwidth. Results of differential cross interferograms are presented showing the coseismic surface displacement caused by the central Italy earthquake.