Minimize SYN Level-1 Processing
Three ADFs are used in Synergy Level-1 processing:
  • The SYN Level-1 Ground Control Points (GCP) Database is a global collection of geographical coordinates and associated window sizes required for SYN (OPT branch) processing. A GCP locates an area that is known to be noteable when observed in a chosen spectral band by OLCI or SLSTR. This means that the imagette extracted around this point will have good correlation properties.

    The database will be constructed during the commissioning phase based on a core database (e.g. VEGETATION 1 mission GCP database) and possibly improved during the early operational phase of SENTINEL-3. The database may also be regularly updated during the life of the satellite. For each GCP, this file includes longitude, geodetic latitude, altitude coordinates and the size of the context window to be extracted around the GCP (on ground, in metres).
     
  • The SYN Level-1 OLCI Inter-Channel Spatial Misregistration data file contains a group of two 2D variables for each OLCI channel, Od d=1,...,21, d#dref, representing the misregistration shift along column and row axes (in OLCI pixel unit) between each detector of the OLCI reference channel, Oref, and the corresponding detector in channel Od, for each camera.
     
  • The SYN Level-1 SLSTR Inter-Channel Spatial Misregistration data file contains one group for each visible (except Su) and 1 km channel (including fire channels) and three groups for each SWIR channel (for A, B and TDI sub-bands). Each group contains the correspondence grid between each pixel acquired during one scan by the SLSTR nadir view reference channel Su and the corresponding location in the other 500 m and 1 km nadir view channels/sub-bands Sb. These data are assumed to be static data from instrument characterisation.
     
  • The SYN map file of the distance to the coast data file is made up of 32 tiles at 2 km resolution (0.0028 degree). For each pixel the distance to the coast is given in km.