Accurate Geometric Calibration of Sentinel-1 Data

Sentinel-1 A and B are twin spaceborne C-band synthetic aperture radar (SAR) sensors developed and operated by the European Space Agency under the Copernicus Earth Observation programme. An accurate geometric cal-ibration has been performed since the Commissioning Phases on operationally generated Level-1 SAR products. In this paper we address the new improvements to the geometric calibration of Sentinel-1A and -1B products, describing corrections applied to the data to remove artefacts such as swath-dependent biases that had previously been observed in corner reflector measurements.