The CryoSat ground segment is organised around two ground stations located in Esrange and Kiruna – both in northern Sweden. This is where contact is established with the satellite, for about 10 minutes 11 times per day, during which commands are sent to the satellite and data downloaded.
Mission and instrument activity planning, however, is performed in ESA’s ESRIN centre in Frascati, Italy. Orbit maintenance (through satellite manoeuvres) is managed by ESA’s operations centre ESOC in Darmstadt, Germany.
It is worth noting that the CryoSat instrument activity is very repetitive, and is based on ground topology (ice boundaries evolving through the year) and a few specific user demands. Therefore, instrument activity is not subject to regular change.
The large amount of data received from the payload, and in particular from the altimeter, is processed at Esrange. Data products at Level-1b (radar echoes geo-located and corrected for instrument features) and Level-2 (ground elevation and ice freeboard, corrected for atmospheric and geo-physical effects) are systematically produced by ESA, based on the repetitive data acquisition planned above. There is no ‘on-demand’ data processing in the routine data production; however, provision is made for troubleshooting needs.
All external auxiliary data needed for the data processing, and in particular the Precise Orbit data is received from the SSALTO centre operated by CNES in Toulouse, with one exception – dynamic sea-ice concentration is received from UCL in London.
Data are routinely distributed to registered users free of charge through internet via high-speed networks.
An important aspect of the CryoSat ground segment is that it is designed for operations with a low level of manpower. Furthermore, remote operations and troubleshooting can be performed on all systems located at the ground stations.