GSC Sentinel-2 PDGS STBD - emits - ESA

GSC Sentinel-2 PDGS STBDIssue 1 Revision 2 (draft) - 25.07.2010GMES-GSEG-EOPG-TN-09-0031page 46 of 60Customarily, the physical network bandwidth is dimensioned to the double of the estimateduseful data rate so as to ensure a correct functioning of this critical component. For example,the physical network bandwidth necessary for the circulation from CGS-1 to PAC-1 would bedimensioned to about twice 87.9 Mib/s i.e. 175 Mib/s for a correct functioning.4.3.1 DATA CIRCULATION IMPACTS ON THE PROCESSING TIMEALLOCATIONIn the scenarios analysis, data processing and data circulation have been completelydecoupled therefore in the budget allowing assessing the duration for data processing thereis no allocation to the data transfer time from the Ground station to the processing centre.This choice is justified by the assumption that data reception and data processing should begenerally collocated. Indeed, n these scenarios, only the data received by the CGS-4 areprocessed by the remote PAC-1 (these data should not include NRT data), for other CGSthe processing is collocated.Considering the circulation data rate estimated in §4.2, one average orbit is transferred fromthe CGS-4 centre to the PAC-1 in:T transfer = DataVolume / DataRate ≈ 7,4 hoursDepending of the actual data transfer bandwidth available, this additional latency should betaken into account in the overall sizing of the sink PAC, to consider the reduced time budgetleft for Level-1C processing to meet the 24 hours end-to-end requirement from sensing.ESA UNCLASSIFIED – For Official Use© 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.