Analysis of Sentinel-1 mission capabilities

The Sentinel-1 mission is designed to be a source of continuous and reliable collection of C-band SAR imagery. Requirements for Sentinel-1 end to end system, as part of the complete family of GMES Sentinels, guarantee continuity of C-band SAR data and products availability to operational entities who exploit satellite radar imagery since ERS 1 operations. Typical drivers for current- and future-generation Remote Sensing LEO satellite missions are fast target access capabilities and short on-board data latency in order to speed up the operations of data download and products' delivery to the end-users. On the other hand complete or almost complete Earth surface coverage is also required from the system. Satellite orbit and sensor swath determine the access capability so that the mission timeliness performance can only improve at the cost of increasing the number of satellites (constellation concept). SAR power demand limits the satellite operational duty cycle implying the need for trade-off between frequent acquisition of the same targets and extension of acquisition surface coverage. A balance between fast access/response to (or frequent revisit of) a few regions of interest and maximization of geographical coverage within the satellite orbit repeat cycle is thus needed when none of the above goals prevail as the main mission driver. Sentinel-1 applies a new operational mission concept; SAR acquisitions by Sentinel-1A (and Sentinel-1B when the constellation will be deployed) are designed according to pre-defined operational sequences to ensure: 1. continuous and systematic acquisition of data all along the mission time (to maximize mission return and system exploitation efficiency); 2. a growing archive of ?world-wide extended? data; 3. maximum extension of coverage after any orbit repeat cycle (175 orbits in 12 days); 4. minimum possible revisit time on few selected regions (North Atlantic Maritime Transport zones, Europe and Canada) but also; 5. possibility to include and perform, as an additional mission capability, sporadic data acquisitions coming from asynchronous user orders submitted to the system following for example requests for specific imagery during emergency occurrences. The mission analysis process performed to define in detail the above operational concept is outlined in this paper and results are presented.