Cornelis Du Toit

The ecosystems SAR (EcoSAR) an airborne P-band polarimetric InSAR for the measurement of vegetation structure, biomass and permafrost

EcoSAR is a new synthetic aperture radar (SAR) instrument being developed at the NASA/ Goddard Space Flight Center (GSFC) for the polarimetric and interferometric measurements of ecosystem structure and biomass. The instrument uses a phased-array beamforming architecture and supports full polarimetric measurements and single pass interferometry. This Instrument development is part of NASAs Earth Science Technology Office Instrument Incubator Program (ESTO IIP).

ECOSAR: P-band digital beamforming polarimetric and single pass interferometric SAR

EcoSAR is a state-of-the-art beamforming synthetic aperture radar (SAR) recently developed at the NASA/ Goddard Space Flight Center (GSFC) for the measurement of ecosystem structure and biomass. The airborne instrument operates at a center frequency of 435 MHz (P-band), and uses a multi-channel reconfigurable architecture to implement fully polarimetric and “single pass” interferometric measurements. The instrument architecture allows for the real-time configuration radar parameters, including center frequency, resolution, incidence angle, and number of beams, among others. The system is also designed to operate in standard or ping pong interferometric modes, and in full, orthogonal, or hybrid polarimteric modes. The instrument development was recently completed, and its first flight campaign successfully conducted in March 2014 over areas of Bahamas and Costa Rica.

Remote sensing of soil moisture using P-band signals of opportunity (SoOp): Initial results

Initial results from the first airborne campaign to evaluate P-band reflectometry for soil moisture remote sensing are presented. P-band radiation has a penetration depth of 10–20 cm, compared to around 5 cm for L-band. This offers the possibility of measuring Root-Zone Soil Moisture (RZSM), a capability that does not presently exist in spaceborne remote sensing. Signals of Opportunity Airborne Demonstrator (SoOp-AD) is a brassboard P-band reflectometry demonstration instrument, developed under the NASA Instrument Incubator Program (IIP-13). Soil reflectivity is estimated from the cross-correlation of direct and reflected signals from a geostationary communication satellite. SoOp-AD will demonstrate key technological advancements on the roadmap to a spaceborne instrument, including an FPGA-based correlator array and “smart antenna” nullsteering in the post-processing stage. The first airborne tests of SoOp-AD were conducted around the ARS Micronet in Little Washita, OK. Initial results confirm the assumption of coherent scattering, show the water-land transition over Lake Ellsworth, and present reasonable values for reflectivity over the instrumented area.

Digital beamforming synthetic aperture radar developments at NASA/Goddard space flight center

Advanced Digital Beamforming (DBF) Synthetic Aperture Radar (SAR) technology is an area of research and development pursued at the NASA Goddard Space Flight Center (GSFC). Advanced SAR architectures enhances radar performance and opens a new set of capabilities in radar remote sensing. DBSAR-2 and EcoSAR are two state-of-the-art radar systems recently developed and tested. These new instruments employ multiple input-multiple output (MIMO) architectures characterized by multi-mode operation, software defined waveform generation, digital beamforming, and configurable radar parameters. The instruments have been developed to support several disciplines in Earth and Planetary sciences. This paper describes the radars advanced features and report on the latest SAR processing and calibration efforts.