Page 1 IGARSS, Denver, July 31-Aug 4, 2006 Sentinel-1 Mission Concept Malcolm Davidson, Evert...
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Transcript of Page 1 IGARSS, Denver, July 31-Aug 4, 2006 Sentinel-1 Mission Concept Malcolm Davidson, Evert...
Page 1IGARSS, Denver, July 31-Aug 4, 2006
Sentinel-1 Mission ConceptSentinel-1 Mission Concept
Malcolm Davidson, Evert Attema, Malcolm Davidson, Evert Attema, Bjorn Rommen, Nicolas Floury,Bjorn Rommen, Nicolas Floury,
Laura Moreno Patricio, Guido LevriniLaura Moreno Patricio, Guido LevriniESAESA
Page 2IGARSS, Denver, July 31-Aug 4, 2006
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: 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
Page 3IGARSS, Denver, July 31-Aug 4, 2006
ESA EO Programme Overview
Application
sServices
Science
ENVISAT
Earth Explorers
Earth Watch
ERS-1, 2
CryoSat1
GOCE
ADM-Aeolus
SMOS
GMES
SwarmEarthcare
95 00 05 10 15
Sentinels
EE7
1 CryoSat-2 in 2009
Page 4IGARSS, Denver, July 31-Aug 4, 2006
Key programmatic guidelines for mission requirements
Continuity of data for user services 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 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
Page 5IGARSS, Denver, July 31-Aug 4, 2006
Derivation of Mission Requirements
User Service Requirements
User Service Requirements
Mission RequirementsMission Requirements System RequirementsSystem Requirements
• Description of service/application
• Description of radar information product
• Geographical Coverage requirements
• Access to data (e.g. timeliness)
• 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. Noise-equivalent Sigma0, Ambiguity ratio, antenna size)
Page 6IGARSS, Denver, July 31-Aug 4, 2006
Monitoring the European marine environment
Include the detection of oil spill pollution and ships
Key observation requirements
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
Page 7IGARSS, Denver, July 31-Aug 4, 2006
Monitoring and Assessing Land Surface-Motion Risk
Driving application: provide pan-European ground motion hazard information service
Key Mission Requirements 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
Page 8IGARSS, Denver, July 31-Aug 4, 2006
Forest Fire and Flood Management
Driving application: support operational service of prevention, anticipation and response to natural hazards
Key Mission Requirements 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
Page 9IGARSS, Denver, July 31-Aug 4, 2006
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 Revisit Coverage Timeliness
Additional mission requirements cover data availability, data product characteristics incl. resolution, radiometric characteristics
Mission Requirements Document (MRD)
Page 10IGARSS, Denver, July 31-Aug 4, 2006
Coverage and Revisit For interferometry, global exact repeat coverage shall be achieved within interval of less than 14 days (MR9) Automatically satisfies applications requiring monthly or annual global coverage
Fast global access on-demand shall be provided (MR10) 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 (MR11) 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
Page 11IGARSS, Denver, July 31-Aug 4, 2006
Avg. revisit time vs. No of Satellites – 250km swath Average Revisit of a Satellite Constellation
with 250 km Swath in 12-175 Orbit
0
1
2
3
4
5
6
7
0.0 10.0 20.0 30.0 40.0 50.0 60.0 70.0 80.0 90.0
Latitude (deg.)
Days
1 sat 2 sat 3 sat 4 sat
Page 12IGARSS, Denver, July 31-Aug 4, 2006
Observation Requirements – Swath Width
The swath width shall be at least 240km (MR15) 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 20km every 100km along track (MR16) Follows from continuity of service requirement
Page 13IGARSS, Denver, July 31-Aug 4, 2006
Observation requirements - polarisation The choice of polarisation depends service => continuity with ENVISAT ASAR implies consideration of HH, VV & cross-pol. 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 (MR17)
Optional additional modes shall be provided incl. HH+HV (MR18)
Page 14IGARSS, Denver, July 31-Aug 4, 2006
Cross-pol. mode for ship detection
For VV+VH mode over water, cross-pol. channel to provide ship information
0
5
10
15
20
25
S/N
29 37 42 57
Incidence
HH
VH
VV
Vachon and Geeling (2005)
Page 15IGARSS, Denver, July 31-Aug 4, 2006
Illustration of dual-polarisation mode over land
Page 16IGARSS, Denver, July 31-Aug 4, 2006
Baseline Technical Concept Orbit: 12 day repeat Operational Modes: IW (5x20m, 240km), EW (25x80m 3L, 400km), SM (4x5m, 80km), WM (20mx5m, 20kmx20km)
Polarisation: Dual pol all modes VV+VH or HH+HV NESZ: -22 dB Radiometric accuracy: 1.0 dB Launch date: mid 2011 Operations:
Consistent, reliable conflict free mission operations NRT delivery within 3h (worst case) with 1h 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)
Page 17IGARSS, Denver, July 31-Aug 4, 2006
ConclusionsConclusions Sentinel-1 mission aims to satisfy its user requirements in terms of data availability, coverage & revisit, timeliness and the quality of its data products. 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: 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