Sentinel-1 Mission Concept Malcolm Davidson, Evert Attema, Bjorn Rommen, Nicolas Floury, Laura Moreno Patricio, Guido Levrini ESA IGARSS, Denver, July 31 -Aug 4, 2006 Page 1
F F Origin of Sentinel-1 Mission Sentinel satellite family represent new development by ESA for Global Monitoring for Environment and Security (GMES) space component Sentinel-1 imaging SAR mission aimed at providing continuity of data for user services Initial mission definition through ESA GSE services with additional inputs from EU GMES activities Main application areas covered: u u u Monitoring sea ice zones and the arctic environment Surveillance of marine environment (wind speed, oil spills, ship detection) Monitoring land surface motion risks Mapping of land surfaces: forest, water and soil, agriculture Support to humanitarian aid in crisis situations IGARSS, Denver, July 31 -Aug 4, 2006 Page 2
95 00 ESA EO Programme Overview 05 10 15 ERS-1, 2 ENVISAT Earth Watch 1 Cryo. Sat-2 in 2009 IGARSS, Denver, July 31 -Aug 4, 2006 GOCE SMOS ADM-Aeolus Swarm Earthcare EE 7 GMES Sentinels Applications Services Earth Explorers Science Cryo. Sat 1 Page 3
Key programmatic guidelines for mission requirements F Continuity of data for user services u u u F Data availability – no data gaps w. r. t. ENVISAT ASAR/ERS-2 Long term commitment to data provision Data quality e. g resolution, radiometry compatible with existing SARs – deviations in system parameters require careful analysis of impact User driven mission u u Respond directly and demonstrably to user requirements Traceability between user, mission and system requirements On-going dialogue with user service community => some users only recently exposed to GMES services through ESA GSE and EU projects Conflict-free satellite operation for reliable access to data and exploitation of archive IGARSS, Denver, July 31 -Aug 4, 2006 Page 4
Derivation of Mission Requirements User Service Requirements • Description of service/application • Description of radar information product • Geographical Coverage requirements • Access to data (e. g. timeliness) Mission Requirements System Requirements • Data availability (Continuity, quality, Operations, Processing and archiving, Distribution) • Coverage and revisit • Timeliness • Characteristics of data products (e. g. spatial & radiometric resolution, swath width, polarisation • Detailed payload, system and ground segment specification of mission (e. g. Noiseequivalent Sigma 0, Ambiguity ratio, antenna size) IGARSS, Denver, July 31 -Aug 4, 2006 Page 5
Monitoring the European marine environment F F Include the detection of oil spill pollution and ships Key observation requirements u u Daily coverage of marine transport corridors Near-real time information delivery (< 3 hours with 1 hour as a goal) Intensity product Co-polar (VV or HH + cross polar) desirable IGARSS, Denver, July 31 -Aug 4, 2006 Page 6
Monitoring and Assessing Land Surface-Motion Risk F F Driving application: provide pan. European ground motion hazard information service Key Mission Requirements u u Interferometry Twice-weekly measurements of subsidence over all major urban areas Regular surveillance over all major urban areas (every two weeks for gas pipelines) Archive for building up time series IGARSS, Denver, July 31 -Aug 4, 2006 Page 7
Forest Fire and Flood Management F F Driving application: support operational service of prevention, anticipation and response to natural hazards Key Mission Requirements u u Seasonal high-resolution imaging of areas burnt by forest fires On-demand rapid delivery of data over hazard Multi-polarisation for best classification results Archive for comparison with past IGARSS, Denver, July 31 -Aug 4, 2006 Page 8
F F F Mission Requirements Document (MRD) Based on analysis and distillation of user requirements from ESA GMES service element program (GSE) Total of 18 mission requirements are formulated and discussed in the MRD (http: //esamultimedia. esa. int/docs/GMES) Three mission design elements appear as keys to meeting user requirements u u u F Revisit Coverage Timeliness Additional mission requirements cover data availability, data product characteristics incl. resolution, radiometric characteristics IGARSS, Denver, July 31 -Aug 4, 2006 Page 9
F Coverage and Revisit For interferometry, global exact repeat coverage shall be achieved within interval of less than 14 days (MR 9) u F Fast global access on-demand shall be provided (MR 10) u F Automatically satisfies applications requiring monthly or annual global coverage Required for humanitarian aid - assumes that revisit time through systematic acquisitions not sufficient Daily full coverage shall be achieved north and south of +45 degree latitude (MR 11) u u Requirement traceable to ice monitoring and marine environment (ship detection, oil spills) services Two satellite baseline not sufficient to meet requirement => collaboration and interoperability with non-ESA SAR system required IGARSS, Denver, July 31 -Aug 4, 2006 Page 10
F Avg. revisit time vs. No of Satellites – 250 km swath IGARSS, Denver, July 31 -Aug 4, 2006 Page 11
Observation Requirements – Swath Width F The swath width shall be at least 240 km (MR 15) u u u F Swath width user requirements often a proxy for revisit/coverage Services mapping fast changing phenomena (sea ice, ship detection) do require a minimum instantaneous swath width Compromise on spatial resolution and radiometric data quality possible for some services (sea ice) but impact others (ship detection, interferometry) A wave mode shall be provided with 20 x 20 km every 100 km along track (MR 16) u Follows from continuity of service requirement IGARSS, Denver, July 31 -Aug 4, 2006 Page 12
F Observation requirements - polarisation The choice of polarisation depends service => continuity with ENVISAT ASAR implies consideration of HH, VV & cross-pol. u u F F Sea ice: currently based on HH or VV, cross-polar shows improved capacity for iceberg detection Wind speed, oil spill detection: require VV Ship detection: HH best for incidence > 45 degrees, cross-pol for steeper incidence angles Services based on land cover classification: require more than one polarisation for enhanced classification The main mode of observation shall be VV+VH (MR 17) Optional additional modes shall be provided incl. HH+HV (MR 18) IGARSS, Denver, July 31 -Aug 4, 2006 Page 13
Cross-pol. mode for ship detection F For VV+VH mode over water, cross-pol. channel to provide ship information Vachon and Geeling (2005) IGARSS, Denver, July 31 -Aug 4, 2006 Page 14
Illustration of dual-polarisation mode over land IGARSS, Denver, July 31 -Aug 4, 2006 Page 15
F F F F Baseline Technical Concept Orbit: 12 day repeat Operational Modes: IW (5 x 20 m, 240 km), EW (25 x 80 m 3 L, 400 km), SM (4 x 5 m, 80 km), WM (20 mx 5 m, 20 kmx 20 km) Polarisation: Dual pol all modes VV+VH or HH+HV NESZ: -22 d. B Radiometric accuracy: 1. 0 d. B Launch date: mid 2011 Operations: u u Consistent, reliable conflict free mission operations NRT delivery within 3 h (worst case) with 1 h goal Data from archive within 24 hours Expected to work in pre-programmed fashion, imaging of global land masses, costal zones, shipping routes (IW) and covering the ocean with imagettes (WV mode) IGARSS, Denver, July 31 -Aug 4, 2006 Page 16
F Conclusions Sentinel-1 mission aims to satisfy its user requirements in terms of data availability, coverage & revisit, timeliness and the quality of its data products. u F F IW forseen as major mode with wide swath, high resolution, multipolarisation, interferometric capability Instrument trade-off studies under way supporting the assessment of radar system parameter impacts Future work: u u International cooperation required to achieve revisit time requirements (interoperability with Canadian radar constellation desirable) Continued verification of mission concept with GMES programmatic requirements and evolution of service community IGARSS, Denver, July 31 -Aug 4, 2006 Page 17
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