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Validation_SWOT_ground_airborne_Fjortoft.ppt
Validation_SWOT_ground_airborne_Fjortoft.ppt
Validation_SWOT_ground_airborne_Fjortoft.ppt
Validation_SWOT_ground_airborne_Fjortoft.ppt
Validation_SWOT_ground_airborne_Fjortoft.ppt
Validation_SWOT_ground_airborne_Fjortoft.ppt
Validation_SWOT_ground_airborne_Fjortoft.ppt
Validation_SWOT_ground_airborne_Fjortoft.ppt
Validation_SWOT_ground_airborne_Fjortoft.ppt
Validation_SWOT_ground_airborne_Fjortoft.ppt
Validation_SWOT_ground_airborne_Fjortoft.ppt
Validation_SWOT_ground_airborne_Fjortoft.ppt
Validation_SWOT_ground_airborne_Fjortoft.ppt
Validation_SWOT_ground_airborne_Fjortoft.ppt
Validation_SWOT_ground_airborne_Fjortoft.ppt
Validation_SWOT_ground_airborne_Fjortoft.ppt
Validation_SWOT_ground_airborne_Fjortoft.ppt
Validation_SWOT_ground_airborne_Fjortoft.ppt
Validation_SWOT_ground_airborne_Fjortoft.ppt
Validation_SWOT_ground_airborne_Fjortoft.ppt
Validation_SWOT_ground_airborne_Fjortoft.ppt
Validation_SWOT_ground_airborne_Fjortoft.ppt
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Validation_SWOT_ground_airborne_Fjortoft.ppt

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  • Page de titre, mentionner contributions Altamira et Cap
  • Spécificités par rapport aux systèmes SAR spatiaux actuels : Bande Ka: impact prévisible de la courte longueur d’onde d’un point de qualitatif (comme listé ici), mais peu de rapport quantitatifs sur sigma_0 Proche nadir : layover, contraste terre/eau, variation fort/rapide de plusieur paramètres qui d’habitude sont quasiment constants ou varient lentement Faire référence à l’article EUSAR où ces aspects sont détaillés (me contacter pour avoir une copie de l’article, il y a eu un problème technique côté organisateur qui fait qu’il n’est pas sur le CD-ROM proc. EUSAR)
  • Transcript

    • 1. Validation of radiometric models and simulated KaRIn/SWOT data based on ground and airborne acquisitions <ul><ul><li>Roger Fjørtoft, Jean-Claude Lalaurie, Nadine Pourthie, Christine Lion, Jean-Marc Gaudin, Alain Mallet ( CNES, Toulouse, France ), </li></ul></ul><ul><ul><li>Jean-François Nouvel, Pierre Borderies ( ONERA, Toulouse/Salon de Provence, France ) , </li></ul></ul><ul><ul><li>Pascal Kosuth ( CEMAGREF, Montpellier, France ), </li></ul></ul><ul><ul><li>Christian Ruiz ( Capgemini, Toulouse, France ). </li></ul></ul>IGARSS 2011, Vancouver, Canada, 25-29 July 2011
    • 2. Outline <ul><li>Introduction </li></ul><ul><ul><li>Context, objectives </li></ul></ul><ul><ul><li>Specificities of KaRIn/SWOT interferometric SAR data </li></ul></ul><ul><li>Modeling and simulation </li></ul><ul><ul><li>Backscattering from various surfaces </li></ul></ul><ul><ul><li>Simulation of raw and SLC radar images </li></ul></ul><ul><li>Airborne acquisitions </li></ul><ul><ul><li>First interferometric Ka-band acquisitions including the KaRIn incidence range (1-4°) </li></ul></ul><ul><li>Near-field Ka-band measurements </li></ul><ul><ul><li>Water backscattering as a function of wind speed and surface roughness </li></ul></ul>
    • 3. Introduction <ul><li>Context </li></ul><ul><ul><li>Original InSAR configuration of KaRIn/SWOT: Ka-band, near-nadir (1-4°) </li></ul></ul><ul><ul><ul><li>Very limited bibliography on backscattering from natural surfaces </li></ul></ul></ul><ul><ul><li>Modeling of Ka-band backscattering (  0 ) </li></ul></ul><ul><ul><ul><li>As a function of surface type, surface conditions, incidence angle, … </li></ul></ul></ul><ul><ul><li>Simulation of raw (L0) and SLC (L1) KaRIn/SWOT interferometric data </li></ul></ul><ul><ul><ul><li>Radiometry and geometry </li></ul></ul></ul><ul><li>Objective: Realize airborne and near-field Ka-band acquisitions </li></ul><ul><ul><li>Compare models and simulations with real data (validate, improve) </li></ul></ul><ul><ul><ul><li>Need for ground truth </li></ul></ul></ul><ul><ul><li>Study important phenomena w.r.t. feasibility and performance </li></ul></ul><ul><ul><ul><li>Coherence, land/water contrast, layover, … </li></ul></ul></ul><ul><ul><li>Enable more realistic input data for algorithm development and testing </li></ul></ul><ul><ul><ul><li>Airborne data and improved simulated images </li></ul></ul></ul>
    • 4. Specificities of KaRIn interferometric SAR w.r.t. existing spaceborne earth observation SAR systems <ul><li>Ka-band (wavelength of only 8.6 mm) [compared to X-, C-, L-band] </li></ul><ul><ul><li>Fewer surfaces appear smooth, implying less specular reflection </li></ul></ul><ul><ul><li>Weaker penetration into vegetation, soil, snow,… </li></ul></ul><ul><ul><li>Higher sensitivity to tropospheric conditions; rain will generally make acquisitions useless </li></ul></ul><ul><ul><li>A smaller baseline can be used for interferometry (10 m mast) </li></ul></ul><ul><ul><li>Few reports on backscattering from natural surfaces, especially in </li></ul></ul><ul><li>Near nadir (0.6-4.1° incidence) [typically 20-50° for spaceborne SAR] </li></ul><ul><ul><li>Layover even in zones of moderate topography (terrain slope > incidence) </li></ul></ul><ul><ul><li>Inversion of land/water radiometric contrast (water > land) </li></ul></ul><ul><ul><li>Strong relative incidence variation, implying strong/rapid range variation in several key parameters (pixel size, altitude of ambiguity, orbital fringes, …) </li></ul></ul><ul><li>For more details, refer to: R. Fjørtoft et al., “ Specificities of Near-nadir Ka-band Interferometric SAR Imagery ”, Proc. EUSAR 2010. </li></ul>
    • 5. Simulation of SLC images (L1) <ul><li>Radiometric simulator: Simulation of RCS for different surface types in various conditions (sensitivity studies, case studies) </li></ul><ul><ul><li>water surfaces, bare soil, trees, </li></ul></ul><ul><ul><li>grass, aquatic vegetation, </li></ul></ul><ul><ul><li>ice, snow (and combinations) </li></ul></ul><ul><li>Geometric simulator </li></ul><ul><ul><li>Integrates results of radiometric simulator </li></ul></ul><ul><ul><li>Geometric effects such as layover and shadow </li></ul></ul><ul><ul><li>Simulation of interferometric pairs of SLC images </li></ul></ul>SAR images Coherence Interferogram DEM Land cover classes EM models Orbit file Layover/ shadow mask e.g. detection of water surfaces, height estimation, … a r
    • 6. Δ T = t 0 – t -1 = t +1 – t o = 1 / PRF -> V t -1 t o t +1 RCS t-1 RCS to RCS t+1 Stacking of all raw images indexed by time Focusing Final RAW data level 1 data Simulation of raw images (L0) e.g. study impact of moving water
    • 7. BUSARD/DRIVE airborne acquisitions (1/2) <ul><li>BUSARD is a Stemme motor-glider operated by ONERA </li></ul><ul><li>DRIVE Ka-band radar integrated in POD </li></ul><ul><li>Interferometry with short (18 cm) or long (4.7 m) baseline </li></ul><ul><li>2.5 W amplifier </li></ul><ul><li>Near-nadir acquisitions (0-14°) with 18 cm baseline in 2011 </li></ul><ul><li>Altitude: 3000 m (9500 ft) </li></ul><ul><li>Swath: 700 m </li></ul><ul><li>Acquisition length: 5 km (2 min) </li></ul><ul><li>PRF: 1250 Hz </li></ul><ul><li>Integration time: 0.2 s </li></ul>
    • 8. BUSARD/DRIVE airborne acquisitions (2/2) <ul><li>Simultaneous ground truth: </li></ul><ul><ul><li>Wind speed </li></ul></ul><ul><ul><li>Water surface roughness </li></ul></ul><ul><ul><li>Water surface height and slope </li></ul></ul><ul><ul><li>Wave height (buoys) </li></ul></ul><ul><ul><li>Soil humidity </li></ul></ul><ul><li>Same day/week/month: </li></ul><ul><ul><li>Soil roughness </li></ul></ul><ul><ul><li>Vegetation characteristics </li></ul></ul><ul><ul><li>Landcover </li></ul></ul><ul><li>Available static data: </li></ul><ul><ul><li>Digital maps </li></ul></ul><ul><ul><li>DEM </li></ul></ul>
    • 9. Espiguette (buoy) Acquisition sites in the Camargue area (2011) Piemanson Vaccarès Rhône
    • 10. voie a Amplitude ~700 m 0° 13° ~2,6 km ~1° 0° ~4° ~10° Trihedrals Artifacts due to wide antenna lobe (right/ left contamination) DRIVE/BUSARD acquisition 24/02/2011 (Rhône)
    • 11. DRIVE/BUSARD acquisition 24/02/2011 (Rhône) Phase
    • 12. DRIVE/BUSARD acquisition 24/02/2011 (Rhône) Coherence >0.9 ~0.7 ~0.3
    • 13. DRIVE/BUSARD acquisition 14/04/2011 (Vaccarès) Amplitude
    • 14. DRIVE/BUSARD acquisition 14/04/2011 (Vaccarès) Amplitude 1 Amplitude 2 Coherence Phase
    • 15. DRIVE/BUSARD acquisition 14/04/2011 (Espiguette) Amplitude
    • 16. DRIVE/BUSARD acquisition 14/04/2011 (Espiguette) Amplitude 1 Amplitude 2 Coherence Phase
    • 17. DRIVE/BUSARD acquisition 25/05/2011 (Rhône) Amplitude
    • 18. Near-field measurements in Ka-band (1/2) <ul><li>Near-field Ka-band measurements of  0 of water with a network analyzer and an automatically steerable (0-10°) parabolic antenna (ONERA) </li></ul><ul><li>Simultaneous measurement of water surface roughness (using immerged pressure sensors) and wind speed (CEMAGREF) </li></ul><ul><li>Rapidly varying wind conditions make the interpretation of the first results complicated. </li></ul>
    • 19. Near-field measurements in Ka-band (2/2) <ul><li>Acquisitions in the Large Air-Sea Interaction Facility (LASIF) at IRPHE (Luminy): 40 m wind tunnel + 40 m water tank </li></ul><ul><li>Possibility to study wind-generated water roughness (waves) in stable conditions (as well as to add mechanically generated waves) </li></ul><ul><li>Additional equipment for optical roughness characterization (IRPHE) </li></ul><ul><li>Comparison of  0 profiles with radiometric models (CapGemini) </li></ul>
    • 20. Water  0 as a function of wind speed Incidence (°/100)  0 (dB) Wind parallel to incidence direction Wind perpendicular to incidence direction  0 (dB) Incidence (°/100)
    • 21. Conclusion <ul><li>Airborne acquisitions with DRIVE/BUSARD </li></ul><ul><ul><li>First interferometric Ka-band acquisitions including the near-nadir incidence range of KaRIn/SWOT (1-4°) </li></ul></ul><ul><ul><ul><li>Confirmation of main feasibility and measurement physics assumptions </li></ul></ul></ul><ul><ul><ul><li>Will allow to refine models and simulators </li></ul></ul></ul><ul><ul><ul><li>Experience gained w.r.t. InSAR processing and ground truth collection </li></ul></ul></ul><ul><ul><ul><li>Hydrology, coastal and ocean test sites covered; possible extension to other surface types: forest, snow/ice, … </li></ul></ul></ul><ul><li>Near field measurements of water surfaces </li></ul><ul><ul><li> 0 as a function of incidence and wind speed / surface roughness </li></ul></ul><ul><ul><ul><li>Interesting phenomena observed; comparison with models ongoing </li></ul></ul></ul><ul><ul><ul><li>Wind-generated roughness only; possibility of adding waves mechanically </li></ul></ul></ul><ul><ul><ul><li>Complementary in situ and wind/water tank measurements </li></ul></ul></ul>
    • 22. SWOT-related presentations in other sessions <ul><li>EXTRACTION OF WATER SURFACES IN SIMULATED KA-BAND SAR IMAGES OF KARIN ON SWOT </li></ul><ul><ul><li>Authors: Fang Cao, Florence Tupin, Jean-Marie Nicolas, Roger Fjørtoft, Nadine Pourthié </li></ul></ul><ul><ul><li>Session: SAR Image Processing I </li></ul></ul><ul><ul><li>Thursday, July 28, 09:20, Ballroom A </li></ul></ul><ul><li>MODELING AND APPLICATIONS OF SWOT DATA </li></ul><ul><ul><li>Authors: Christine Lion, Konstantinos Andreadis, Roger Fjørtoft, Florent Lyard, Nadine Pourthié, Jean-François Crétaux </li></ul></ul><ul><ul><li>Session: Wetlands and Inland Waters II </li></ul></ul><ul><ul><li>Thursday, July 28, 13:40, Room 12 </li></ul></ul>

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