ESTO-IIP 2011-2014 Introduction Goddard Space Flight Center EcoSAR - - PowerPoint PPT Presentation

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ESTO-IIP 2011-2014

Goddard Space Flight Center

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Introduction

• 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) .

ESTO-IIP 2011-2014

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Science Question

How are the Earth's carbon cycle and ecosystems changing, and what are the consequences for the Earth's carbon budget, ecosystem sustainability, and biodiversity? The CARBON CYCLE. Carbon in the atmosphere is a controlling factor

• n climate and hence on ecological productivity and the

sustainability of life.

Science Driver

EcoSAR will acquire unique measurements that will help us quantify carbon in vegetation, and how it is changing.

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Instrument Science Rationale

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 is sensitive to the shape,

• rientation and

dielectric properties of scatterers and allows the identification and separation of the scattering mechanisms.

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HH HV

Pol-InSAR height measurements:

• InSAR is highly sensitive to the spatial variability of

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 scattering phase center HH scattering phase center

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EcoSAR Main Science objectives

• 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

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EcoSAR Architecture

Radar Transceivers, Antenna Subarrays, and Synthesizer/Acquisition and Processor (SAP) Unit

• 18 transceivers support polarimetric and

interferometric measurements.

• Each antenna consists of 9 dual polarization, high

bandwidth subarrays.

• 18 Waveform generators directly synthesize P-band

signals with up to 200 MHz bandwidth.

• 18 Receivers will sample the radar returns directly.
• Synthesizer/Acquisition and Processor system will be

designed around the Xilinx Virtex 5 FPGA.

• Digital I&Q demodulation, decimation and filtering will

be performed on board.

• Processor supports subsequent onboard radar

processing (e.g., digital beamforming, SAR image formation, multi-look, etc…)

Antennas SAP SBIR Prototype by IAI

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EcoSAR System description

EcoSAR will fly on the NASA P3 airplane based at Wallops Flight Facility

Center Frequency 435 MHz Pulse Length 1 usec – 50 usec Maximum Bandwidth 200 MHz Array Peak Power 40 Watts Polarization HH, VV, VH,HV PRF 100 Hz – 10 KHz Polarization Isolation < 25 dB Swath 4 km – 8 km Noise Equivalent σo

• 41 dB *

Finest Range Resolution 0.75 m Total Number Channels 36 Single Look Azimuth Resolution 0.5 m Interferometric baseline 25 m Vertical Accuracy < 5 m

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EcoSAR Concept

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EcoSAR Concept

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EcoSAR Concept

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Height (m)

Example of SAR and InSAR using DBSAR (L-band) measurements

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S w a t h 2

Flight Path

rx ry

θ2 Antenna

S w a t h 1 rx ry

θ1

F L I G H T T R A C K

Example of multiple beam technique

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EcoSAR Resolution

Low Resolution Medium Resolution High Resolution

Slant Ground Azimuth (Cross Range) Resolution

0.5 m (single look) 25 m 44 m 5 m 8.7 m 0.75 m 1.3 m

Range Resolution

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3 m 1.0 m

EcoSAR Antennas

Subarray S11 and S22 parameters Cross coupling is below -80dB

Antenna Parameters

Type Micro-Strip Patch Center Frequency 435 MHz Bandwidth 200 MHz Gain 19 dB Area 3 m2 Polarization Dual, linear Cross Polarization Isolation < 25 dB Number of Sub Arrays 9 Total Number of Elements 27

Three-element subarray Each antenna array mounts the P3 aircraft wing The EcoSAR antenna arrays will allow to steer the beam across track

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Year 1 Definition of the EcoSAR science and system requirements Antenna Arrays Design and fabrication Radar Electronics Unit Design and fabrication Year 2 Completion of Waveform generator/data system Testing and programming of waveform generator/data system Radar Electronics evaluation, testing and initial assembly. Full system integration and testing in laboratory and in anechoic chamber. Year 3 Installation and test flight operation of the system on the NASA P-3 aircraft Validation of EcoSAR test flight data sets Field Campaign 1 New Hampshire and Maine Field Campaign 2 Costa Rica Science Retrievals from EcoSAR campaigns

Schedule and Milestone

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Concluding Remarks

• Our team has successfully completed the design of prototype dual

polarized wideband P-band antenna element. A full array simulation is underway.

• The aerodynamic analysis on antenna structure has been

performed.

• The radar transceiver schematic has been completed.

Components specifications and availability are currently being investigated.

• The processor development is scheduled to begin in August 2011.

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End of Presentation