EcoSAR Technology IGARSS Presentation.pdf


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EcoSAR Technology IGARSS Presentation.pdf

  1. 1. Goddard Space Flight CenterESTO-IIP 2011-2014
  2. 2. Introduction Goddard Space Flight Center •EcoSAR is a new radar development at NASA/Goddard Space Flight Center for the measurements of terrestrial ecosystem structure and biomass. •The EcoSAR measurements will directly support science requirements for the study of the carbon cycle and its relationship to climate change. •EcoSAR will use Electronic Beam Steering and Digital Beamforming to implement Polarimetric and Interferometric Synthetic Aperture Radar (SAR) . 2ESTO-IIP 2011-2014
  3. 3. Science Driver Goddard Space Flight CenterThe CARBON CYCLE. Carbon in the atmosphere is a controlling factoron climate and hence on ecological productivity and thesustainability of life. Science QuestionHow are the Earths carbon cycle and ecosystems changing, andwhat are the consequences for the Earths carbon budget,ecosystem sustainability, and biodiversity? EcoSAR will acquire unique measurements that will help us quantify carbon in vegetation, and how it is changing.3
  4. 4. Instrument Science Rationale Goddard Space Flight Center P-band SAR penetrates vegetation structure allowing the sensing of the entire canopy volume and woody density. Such measurements can be directly related to aboveground biomass. SAR measurements can be performed in most weather conditions and provide the capability of mapping the vegetation cover and changes due to natural and human- induced disturbances frequently.Polarimetric radar issensitive to the shape,orientation anddielectric properties ofscatterers and allowsthe identification andseparation of thescattering mechanisms.4
  5. 5. Pol-InSAR height measurements: - InSAR is highly sensitive to the spatial variability of Goddard Space Flight Center vertical structure parameters and enables accurate 3D localization of the scattering center. - EcoSAR will implement Pol-InSAR techniques to provide measurements that will allow us to separate ground from canopy and derive canopy height and to investigate the 3-D structure of volume scatterers . HV HHHV scatteringphase centerHH scatteringphase center
  6. 6. EcoSAR Main Science objectives Goddard Space Flight Center• EcoSAR instrument will quantify: – Biomass – Canopy and Surface Height – Ecosystem structure and extent – Disturbance and recovery• Science Goals – Height with 1 m accuracy from single-Pass Polarimetric Interferometry – Biomass up to 200 Mg/ha from PolSAR measurements alone – Resolution of 0.75 m in range• Additional Science : – Solid Earth: deformation and subsidence – Cryo: ice sheet and permafrost depth – Hydro: surface water extent, salinity, soil moisture – Applications: soil/canopy penetration for archaeological studies
  7. 7. EcoSAR Architecture Goddard Space Flight Center• 18 transceivers support polarimetric andinterferometric measurements.• Each antenna consists of 9 dual polarization, highbandwidth subarrays. Radar Transceivers, Antenna Subarrays, and Synthesizer/Acquisition and Processor (SAP) Unit• 18 Waveform generators directly synthesize P-bandsignals with up to 200 MHz bandwidth.•18 Receivers will sample the radar returns directly.•Synthesizer/Acquisition and Processor system will bedesigned around the Xilinx Virtex 5 FPGA. Antennas• Digital I&Q demodulation, decimation and filtering willbe performed on board.• Processor supports subsequent onboard radarprocessing (e.g., digital beamforming, SAR imageformation, multi-look, etc…) SAP SBIR Prototype by IAI
  8. 8. EcoSAR System description Goddard Space Flight CenterCenter Frequency 435 MHz Pulse Length 1 usec – 50 usecMaximum Bandwidth 200 MHz Array Peak Power 40 WattsPolarization HH, VV, VH,HV PRF 100 Hz – 10 KHzPolarization Isolation < 25 dB Swath 4 km – 8 kmNoise Equivalent σo - 41 dB * Finest Range Resolution 0.75 mTotal Number Channels 36 Single Look Azimuth 0.5 m ResolutionInterferometric baseline 25 m Vertical Accuracy <5m EcoSAR will fly on the NASA P3 airplane based at Wallops Flight Facility
  9. 9. EcoSAR Concept Goddard Space Flight Center
  10. 10. EcoSAR Concept Goddard Space Flight Center
  11. 11. EcoSAR Concept Goddard Space Flight Center
  12. 12. Example of SAR and InSARusing DBSAR (L-band) measurements Goddard Space Flight Center Height (m)
  13. 13. Example of multiple beam technique Goddard Space Flight Center t Path nna Fligh Ante θ1 θ2 ry rx Swath 1 ry rx Swath 2 F L I G H T T R A C K
  14. 14. EcoSAR Resolution Goddard Space Flight Center Azimuth (Cross Range) Resolution 0.5 m (single look) Range ResolutionSlant Low Resolution Ground25 m 44 m Medium Resolution5m 8.7 m High Resolution0.75 m 1.3 m
  15. 15. EcoSAR Antennas Goddard Space Flight Center Antenna Parameters Type Micro-Strip Patch Center Frequency 435 MHz Bandwidth 200 MHz Gain 19 dB Area 3 m2 Polarization Dual, linear Each antenna array mounts the P3 aircraft wing Cross Polarization Isolation < 25 dB Number of Sub Arrays 9 Total Number of Elements 27 3m Three-element subarray 1.0 mThe EcoSAR antenna arrays will allow to steer the beam across track Subarray S11 and S22 parameters Cross coupling is below -80dB
  16. 16. Schedule and Milestone Goddard Space Flight Center Year 1Definition of the EcoSAR science and system requirementsAntenna Arrays Design and fabricationRadar Electronics Unit Design and fabrication Year 2Completion of Waveform generator/data systemTesting and programming of waveform generator/data systemRadar Electronics evaluation, testing and initial assembly.Full system integration and testing in laboratory and in anechoic chamber. Year 3Installation and test flight operation of the system on the NASA P-3 aircraftValidation of EcoSAR test flight data setsField Campaign 1 New Hampshire and MaineField Campaign 2 Costa RicaScience Retrievals from EcoSAR campaigns
  17. 17. Concluding Remarks Goddard Space Flight Center• Our team has successfully completed the design of prototype dualpolarized wideband P-band antenna element. A full arraysimulation is underway.• The aerodynamic analysis on antenna structure has beenperformed.• The radar transceiver schematic has been completed.Components specifications and availability are currently beinginvestigated.• The processor development is scheduled to begin in August 2011.
  18. 18. Goddard Space Flight CenterEnd of Presentation