GSC Sentinel-2 PDGS STBD - emits - ESA

3 PDGS PROCESSING BUDGET ANALYSISESA UNCLASSIFIED – For Official UseGSC Sentinel-2 PDGS STBDIssue 1 Revision 2 (draft) - 25.07.2010GMES-GSEG-EOPG-TN-09-0031page 6 of 60This chapter provides an analysis of the data processing budget for the Sentinel-2 PDGS.After this introductory part, the Sentinel-2 Level-0 and Level-1 processing benchmarks aredescribed. The next section provides an overview of the parallelisation opportunitiesassociated to every processing step. In a last section, preliminary processing budget figuresare estimated together with a description of the rationale of the calculations and associatedassumptions.3.1 Introduction3.1.1 PDGS PROCESSING SYSTEMThe PDGS processing system will be composed of hardware and software elements whichcan be mapped one another into processes which gradually carry out the overall processingin a controlled stepwise approach. In this model, every software element will implement a“processing step” using a given hardware element as work horse.Recalling the PDGS functional decomposition presented in [RD-02], the unitary processingstepsimplement the Instrument Data Processing (IDP) functional element while the DataProcessing Control (DPC) element structures, triggers and controls every step within theoverall workflow.In this framework, the Instrument Processing Facility (IPF) is the realisation of the IDPfunctionality into independently controlled processes hereafter referred to as “IPFcomponents”. In counterpart, the DPC functionality will be translated into a supervisioninfrastructure which composes and executes the workflow by means of separately controlledIPF components on the available hardware resources.3.1.2 PROCESSING RATIONALE AND TIMELINE CONSTRAINTSThe study of the PDGS operational processing scenarios to meet the various timelinessconstraints summarised in section 2.2 has led to a simple model in which:- The data is processed systematically up to Level-1C from every raw-data acquisitionperformed at every station. The collection of MSI data received at one station at aparticular orbit is hereafter referred to as a “datastrip”;- The processing follows a FIFO rule in which the data received first is processed firstwithin the datastrip. This model ensures that the processing strictly follows the prioritiesset in the downlink sequence (RT downlink or prioritised downlink via the NRT store),hence resulting in a product availability timeliness directly inherited from the downlinkplan;- The data processing resource is sized such as to ensure that the end-to-end timelinessconstraints are fulfilled after every datastrip processing, and that the resource issystematically freed for the next datastrip processing at the same station.Because of the need for Satellite Ancillary Data (SAD) to complete the MSI data processing,the processing sequence is driven by two triggers: the MSI data downlink and the SAD© ESAThe copyright of this document is the property of ESA. It is supplied in confidence and shall not be reproduced, copied orcommunicated to any third party without written permission from ESA.