Extending the Sentinel-1 Timing Annotation Datasets using the ESA S1-ETAD service

The European Space Agency (ESA) is supporting the implementation and testing of a new processor hosted on the Geohazards Exploitation Platform as a service.

The Sentinel-1 Extended Timing Annotation Dataset (S1-ETAD) service provides timing correction for Sentinel-1 IW and SM SLC products i.e. it does not generate any EO products but correction data provided in NetCDF format. Such correction data allow achieving greatly improved geodetic accuracy up to few centimetres. This processor encompasses ionosphere corrections, troposphere corrections, and solid tide earth time corrections. In addition, corrections for “system effects” on the Sentinel-1 timing (Doppler shift, accurate bi-static correction and height-dependent FM-rate mismatch) are also provided. To generate such corrections, the service uses precise information from different ancillary data sources such as IGS and ECMWF.

The service improves the Sentinel-1 timing to reach centimetre level accuracy allowing to improve the ground motion sensitivity in applications such as DInSAR, PSI, SBAS and offset tracking.

The service implements a service based on the algorithm published by C. Gisinger et al., “In-Depth Verification of Sentinel-1 and TerraSAR-X Geolocation Accuracy Using the Australian Corner Reflector Array,” in IEEE Transactions on Geoscience and Remote Sensing, vol. 59, no. 2, pp. 1154-1181, Feb. 2021, doi: 10.1109/TGRS.2019.2961248.

ESA is planning to start shortly a Test pilot involving experts in several domains which will show the benefits of applying such corrections in their workflows.

If you are interested and want to get involved in the Test Pilot, please refer to gep-team@esa.int

More information about S1-ETAD, dataset structure, python API and more can be found in here.