GSHAP L. Wood, P. Worfolk et al., SaVi - Satellite constellation Visualisation software, http://savi.sf.net/, 2010. Paul A. Rosen Jet Propulsion Laboratory, California Institute of Technology UNAVCO Workshop Boulder, Colorado March 10, 2010
Outline Background Planned International Radar Missions DESDynI (NASA) Data Access Summary
The Solid Earth Science Working Group Report Recommendations
The Solid Earth Science Working Group Report Recommendations 1-5 years
The Solid Earth Science Working Group Report Recommendations 5-10 years
The Solid Earth Science Working Group Report Recommendations 10+ years
SAR/InSAR Earth Missions Toward Realizing SESWG SeaSAT Challenger SIR-A SIR-B RB SIR-C/ X-SAR SRTM DESDynI ERS-1 ERS-2 Envisat-1 Sentinel 1a/b JERS-1 ALOS ALOS-2 RADARSAT-1 RADARSAT-2 TerraSAR-X TanDEM-X Cosmo-Skymed 1980 1985 1990 1995 2000 2005 2010 2015 From: Rosen and Buccolo (2007) IEEE Radar Conference
And yet Current SAR satellite capabilities continue to have their limitations Non-uniform and limited coverage Monthly sampling Coherence issues Commercialization (Data access in general is improving greatly, though) The next generation of InSAR systems will need to address these issues
Next Generation InSAR-Capable Systems System Agency # of birds Sentinel-1A/ 1B ALOS-2 Radarsat Constellation DESDynI SAOCOM-1 A/1B Repeat Period Band ESA (2012) 2 12-day/6-day C JAXA (2013) CSA (2014-15) NASA (2017) CONAE (2013) Modes 1 14-day L Multiple 3 12-day/4-day C Multiple 1 8-day L 2 16-day/8-day L Multiple Multiple, primary: wideswath InSAR Multiple, primary: wideswath Pol/InSAR TerraSAR-N DLR (?)?? X Commercial Many others
Sentinel-1 Concept Space component of the EU/ESA initiative on Global Monitoring for Environment and Security (GMES) Driven by end user requirements not by Earth observation research Marine Services Land Monitoring Services Emergency/Disaster Frequent observations Operational Emphasis on information products (Sampling using Two Satellites) From: Sentinel-1 The Radar Mission for GMES Operational Land and Sea Services (2007), Attema et al.
Sentinel-1 Operating Modes From: The GMES Space Component perspective, 4-th e-collaboration workshop, ESRIN 25 Feb 2009
Sentinel-1 Characteristics Lifetime: 7 years (consumables 12 years) Orbit: near-polar Sun-synchronous 693 km; 12-day repeat cycle; 175 revs per cycle Mean Local Solar Time: 18:00 at ascending node Orbital period: 98.6 minutes Orbit knowledge: 10 m (each axis, 3-sigma) using GPS Operating autonomy: 96 hours Spacecraft availability: 0.998 Science data storage capacity: 900 Gb (end-of-life) X-band data rate: 600 Mbit/s From: Sentinel-1 The Radar Mission for GMES Operational Land and Sea Services (2007), Attema et al.
- Continue the ALOS mission with enhanced performance - Comprehensive land monitoring (land infrastructure management, resource management and resource exploration) - Provide timely observation [day time <3 hours and night time <6 hours (80%) by adding foreign satellites] with high resolution [1 3 m] and wide coverage [50 km] for disaster management in Japan, and contribute to the international disaster management - Pathfinder of potential use by enhanced performance ALOS-2 L-band SAR Spotlight, Stripmap, ScanSAR mode Right- and left-looking by spacecraft maneuvering Single, Dual, Compact and Full polarimetry From: S. Suzuki (2009), ISTS 2009 ALOS-2 Overview Parameter RF band RF band width Weight SAR antenna size SAR data compression Data transmission rate Max. transmission power Observation duty ALOS-2 target specification Value L-band 85MHz SAR : approx. 640kg Spacecraft : approx. 2 tons 3m (El) * 10m (Az) Active phased array antenna 2 or 4 bit (raw data 8 bit) DT [X-band] : 840M/420Mbps Data relay [Ka-band]: 278Mbps 4000-6000W 30 % per orbit Launch Early 2013
ALOS-2 SAR observation modes SAR observation modes and performance Performance @ incident angle 37deg CP: Compact Polarimetry, FP: Full Polarimetry (HH+HV+VV+VH) 70 160km no obs around nadir 8 8 350 km 25 km 25km 70 50 km ScanSAR Spotlight Observation area Stripmap From: Y. Kankaku (2009) PIERS Proceedings, Moscow, Russia, August 18-21, 2009
RCM Observational Characteristics Daily coverage of Canada's inland, territorial and adjacent waters to support maritime surveillance, including ice monitoring, marine wind monitoring, oil pollution monitoring and ship detection; Ability to image any disaster location in the world within 24 hours to establish the state of critical infrastructure; Ability to monitor all of Canada for disaster mitigation on a regular basis (monthly to twice-weekly) to assess risks and identify damage prone areas; and, Regular coverage of Canada's land mass and inland waters, up to several times weekly in critical periods, for resource and ecosystem monitoring 3 satellites equally-spaced in a dawn-dusk plane Antenna - 9.45m 2 Power - < 1600 W (peak); < 220 W (average) Orbit - 600 km, 100 m radius orbital tube Polarisation - Dual cross selectable pol on all low and medium resolution modes; "experimental" quad pol Imaging Time - 12 minutes/orbit (peak 20 minutes every three orbits) 10 minutes continuous imaging Lifetime - 7 years (each satellite) http://www.asc-csa.gc.ca/eng/satellites/radarsat/description.asp
http://www.asc-csa.gc.ca/eng/satellites/radarsat/description.asp
Recommended by the NRC Decadal Survey for near-term launch to address important scientific questions of high societal impact: What drives the changes in ice masses and how does it relate to the climate? How are Earth s carbon cycle and ecosystems changing, and what are the consequences? How do we manage the changing landscape caused by the massive release of energy of earthquakes and volcanoes? Planned by NASA as one of the following 4 Decadal Survey TIER 1 Missions SMAP ICESat-II DESDynI CLARREO Ice sheets and sea level Will there be catastrophic collapse of the major ice sheets, including Greenland and West Antarctic and, if so, how rapidly will this occur? What will be the time patterns of sea level rise as a result? Shifts in ecosystem structure and function in response to climate change How will coastal and ocean ecosystems respond to changes in physical forcing, particularly those subject to intense human harvesting? How will the boreal forest shift as temperature and precipitation change at high latitudes? What will be the impacts on animal migration patterns and invasive species? Extreme events, including earthquakes and volcanic eruptions Are major fault systems nearing release of stress via strong earthquakes Eruptive state of volcanoes? Deformation Biomass Ice Dynamics
Polarimetric SAR Multibeam LIDAR Canopy Height g t Biomass Biomass Vegetation Structure Vegetation Disturbance Sea Ice Thickness Repeat Pass InSAR Pass 1 Pass 2 Effects of changing climate on habitats and CO 2 Response of ice sheets to climate change & sea level rise DESDynI will exploit an L-band polarimetric radar operated interferometrically (InSAR) and multibeam lidar Sea Ice and Ice Sheet Dynamics Changes in Earth s Surface Geo-Hazards
Common theme in these three disciplines, reflected in mission requirements: Need for finer spatial and temporal sampling DESDynI will join the international fleet of missions to deliver suitable sciencedriven observations with sufficient coverage and sampling Mission Characteristics fulfilling these needs: Multi-year (3/5) mission to observe global scale change L-band synthetic aperture radar (SAR) system - Frequent (8-day) revisit to observe fast processes - Repeat-pass Interferometer (InSAR) for mm-scale accuracy - Multiple polarization for hectare scale biomass and change - Viewable swath of 360 km for complete global coverage at 8 days - 10 m intrinsic ground resolution Multiple-beam (5) lidar - Operating in the infrared (1,064 nm) for sensitivity to canopy - 25-m spatial resolution per beam sampled along-track every 30 m - Sub-meter vertical profiles within 25-m footprint - 250 m resolution grid after 5 years 19 19
Science Requirement Measurement Requirement Instrument Requirement Ecosystem Structure Global Biomass/Carbon Global Biomass Change Global Biodiversity Dynamics of Ice Ice sheet dynamics Glacier dynamics Sea ice dynamics Deformation Tectonic processes Magmatic processes Sequestration, landslides, and aquifer change Canopy height and structure metrics accurate to 1 m accuracy (0 slope) at 250-500 m spatial resolution in 5 yrs Biomass at 100 m spatial resolution in low biomass areas Forest change maps, annually 2-D velocity accurate to 1 m/yr at 100-500 m spatial resolution over ice sheets and glaciers, 5 yrs DEM topography accurate to 1 m at 1 km spatial resolution over ice sheets and glaciers Elevation precise to 3 cm at 25 m profile resolution over sea ice 2-D deformation rates accurate to 1 mm/yr over 50 km length scale at 100-1000 m spatial resolution 2-D deformation accurate to 5-20 mm over 50 km length scale at 100 m resolution, weekly sampling 5-beam profiling lidar operated at near nadir incidence, 25 m profile resolution, Lidar 91-day repeat orbit Quad-pol L-band radar operating in 30-46 incidence angles at 10 m resolution, seasonally 5-beam profiling lidar operated at near nadir incidence, 25 m profile resolution Lidar 91-day repeat orbit L-band radar operating in 8-day repeat period orbit, global accessibility, at 10 m resolution, continuously over mission Left/Right pointing L-band radar operating in 8-day sampling period orbit Global accessibility 10 m resolution All continuously over mission Left/Right pointing
Interseismic strain accumulation at diffusive plate boundary deformation zone An accuracy of 1 mm/yr is needed to study interseismic strain accumulation, plate boundary deformation e.g., Northern metropolitan Los Angeles is shortening at 5 mm/yr. Strain is building up above the Puente Hills Thrust fault. Argus et al. 2005 5 mm/yr projected onto InSAR line of sight is 2 mm/yr. Donald Argus
Zhen Liu
Accuracy improvement by stacking in time Troposphere delay is uncorrelated over several days. If rate is constant, stacking interferograms improves accuracy Stacking interferograms generated every 24 days improves InSAR accuracy to: 1.0 mm/yr 5 year mission 2.2 mm/yr 3 year mission (standard error, horizontal distance 50 km). generated every 8 days 0.6 mm/yr 5 year mission 1.3 mm/yr 3 year mission Donald Argus
761 km altitude 8-day repeat 360 km Swath Descending Track Right (Starboard) Pointing Incidence angles 30-50 degrees 360 km Adjacent Equatorial Ground Track Separation Ascending Track Right (Starboard) Pointing Incidence angles 30-50 degrees 360 km Swath 761 km altitude 8-day repeat NOTE: NOT TO SCALE! 360 km Adjacent Equatorial Ground Track Separation
761 km altitude 8-day repeat Descending Track Left (Port) Pointing Incidence angles 30-50 360 km Swath 360 km Adjacent Equatorial Ground Track Separation 761 km altitude 8-day repeat Ascending Track Left (Port) Pointing Incidence angles 30-50 degrees 360 km Swath NOTE: NOT TO SCALE! 360 km Adjacent Equatorial Ground Track Separation
2 observations (1 ascending, 1 descending) in an 8-day cycle Descending Left-Looking coverage shown: Ascending Plan is to acquire this map every cycle Yearly data volume for Solid Earth Science: 163 TB 26
Assumes freedom to point left or right at will to target a particular observation Mean Access Interval (Days) 4 2 1.3 1 Steven Hu, JPL
The DESDynI Mission will produce a wide range of products for three distinct science communities Global Ice Global Biomass Tectonic and Volcanic Active Regions Observation Targets (Colored) Some Product Characteristics: 2-D deformation maps of ice sheets - Complete coverage yearly, 100 1000 m resolution, l ti 11 5 m /yr / accuracy 2-D sea-ice motion at both poles - Weekly polar coverage, 5-km resolution, 100 m / day accuracy Biomass and biomass change - Global coverage yearly, 100-1000 m resolution, accuracy of better than 20% 2-D deformation maps of Earth s most severe geohazards - Weekly to yearly over Earth s deforming margins, 20 100 m resolution, accuracy from mm cm / yr Sea-ice thickness - Monthly-yearly polar coverage, 25 km resolution, better than 60 cm accuracy 28
15 m mesh reflector Stowed for Launch in EELV Fairing 4.7 m L-band Polarimetric Radar Feed
Strip-mode SAR Standard SAR mode Send a pulse of energy; receive echo; repeat One pulse transmit and receive at a time Swath width limited by radar ambiguities ScanSAR Wider swath low resolution SAR mode Execute sequence as follows: Send a pulse of energy; receive echo; repeat 50-100 times Repoint the beam across-track to position 2 electrically (almost instantaneous) Send a pulse of energy; receive echo; repeat 50-100 times Repoint the beam across-track to position 3 electrically (almost instantaneous) Send a pulse of energy; receive echo; repeat 50-100 times Again, one pulse transmit and receive at a time ScanSAR trades resolution (in along-track dimension) for swath: low impact on data rate Generally poorer ambiguity and radiometric performance than Strip SAR StripSAR ScanSAR 30
What is SweepSAR? Transmit pulse over wide beam in elevation Receive echo over narrow beam tracking echo with scanning receive e beam Can require multiple simultaneous receive beams to track multiple echoes A completely new capability Solves the traditional large, complex antenna problem with a large passive reflector and compact digital feed electronics Breaks the standard SAR performance limits by separating transmit and receive apertures with digital beamforming techniques SweepSAR achieves very high h area coverage rates at fine, selectable resolutions, full polarization 31
DESDynI is in the formulation phase (pre-phase A) - Radar satellite and instrument being designed by JPL - Lidar satellite and instrument being designed by GSFC Level 1 Science Requirements have been drafted by Steering Group in preparation for Mission Concept Review (MCR) Designs for Radar and Lidar spacecraft and Operations Concept meeting these L1 requirements are reaching maturity for MCR Current plan is to enter Phase A in FY11 President s budget seeks to accelerate all Decadal Survey Mission, including DESDynI 32
Mission Sentinel-1A/1B Operations Concept One mode: InSAR Wide Swath, but where? Data Distribution Method Cloud Storage and Distribution; details TBD Data Policy Free and Open Access; details TBD ALOS-2 Campaign; disasters Data Nodes?** Toward Commercial** Radarsat Constellation DESDynI Canada-centric; disasters Systematic Science Observations; disasters ** Observation Plan similar to ALOS-1 is likely New Data Distribution Model Science Nodes; exploring cloud technologies AO driven? And there will be other missions as well providing data Free and Open Access
There is a new generation of radar satellites being designed to deliver unprecedented quantities of SAR data This gives a great potential for the InSAR research community to have the kind of data it has been requesting for years Fast-repeat Global Unrestricted Geodetic-grade Whether these data can be used to realize the InSAR potential will depend on many factors, especially data acquisition strategy and data policy Sentinel-1A/1B, albeit at C-band, and possibly other systems seem to be poised to deliver useful data DESDynI is being designed specifically to realize this potential InSAR Everywhere, All the Time is fast approaching!