All data acquired by the MSI instrument are systematically processed to Level-1C by the Payload Data Ground Segment (PDGS). Only the Level-1C and Level-2A products are released to Users. Level-2A products are generated either by the PDGS using the Sen2Cor processor, or on the User side through the Sentinel-2 Toolbox.
Figure 1: Processing levels from Level-0 to Level-1C. (Level-0, Level-1A and Level-1B products are PDGS internal products not made available to users.)
The processing from Level-0 to Level-1C is performed by the Instrument Data Processing (IDP) functionality of the PDGS. The quality of generated products is assessed by the On Line Quality Control (OLQC) functionality. The OLQC performs essential quality checks on each product generated by the processing chain. The results of the quality checks are presented as XML reports and GML quality masks.