Sentinel-1 Analysis Ready Data

This dataset is the Sentinel-1 Analysis Ready Data (ARD) archive for Switzerland.

Detailed description about the Sentinel-1 missions can be found in the CEOS Earth Observation Handbook: Sentinel-1A (http://database.eohandbook.com/database/missionsummary.aspx?missionID=575) and Sentinel-1B (http://database.eohandbook.com/database/missionsummary.aspx?missionID=576).

To produce Sentinel-1 Analysis Ready Radiometrically Terrain Corrected (RTC) products, ground range detected (GRD) products are downloaded from the EU scihub.copernicus.eu. A digital elevation model (DEM) is then used to generate an image simulation of the local contributing area within each image sample. That area is used to normalise the backscatter (rather than the ellipsoid model otherwise typically used) in ground range geometry. Then that normalized backscatter is terrain-geocoded (orthorectified) into the chosen map coordinates, producing a level-1 RTC product. Sets of multiple RTC products acquired from different orbit tracks within a tight temporal window are then combined using local resolution weighting into level-3 multitemporal backscatter composite products. The region covered is latitude 44.5 to 48.5N, longitude 5.5-11E, at 90m spatial resolution and 6 day temporal spacing.

The geometry of Sentinel-1 data is well calibrated: data can be geocoded without any tiepoints to an accuracy of a few centimeters , far better than is possible with optical sensors. Sentinel-1 radiometric stability is monitored and calibrated within the Sentinel-1 Mission Performance Centre. A broad review of the quality of multiple implementations of radiometric terrain correction (RTC) processing was provided in. The quality of the terrain correction and radiometric corrections depends on the quality of the input DEM made available. Participants in the Copernicus programme (currently not including Switzerland) are able to access a world-wide high-quality DEM with 30m resolution, with 10m models available in some regions.