Proposal Title: Two Dimensional Synthetic Aperture Radiometer for Microwave Remote Sensing from Space
Aperture synthesis is an interferometric technique which has the potential to improve the resolution of future passive microwave instruments in space. This proposal is to develop an aircraft prototype instrument employing aperture synthesis in two dimensions using an antenna configuration and digital processing architecture that is scalable to high resolution instruments in space. The aircraft instrument will demonstrate that one can achieve a viable signal-to-noise ratio and calibration for a sensor in space with high resolution that is deployable with a modest launch vehicle. It will also demonstrate the potential for conical scan and fully polarimetric operation with a radiometer thinned in two dimensions. The aircraft instrument will be configured to demonstrate these issues at a wide range of frequencies, but it will be built to operate at L-band. This choice was made because the problem of achieving adequate spatial resolution is most critical at the long wavelengths; Also, imaging airborne instruments are difficult to build at this frequency and will be needed in the future for experiments to validate soil moisture and ocean salinity retrieval algorithms. This research will be conducted by the NASA/Goddard Space Flight Center (GSFC), the University of Massachusetts and Quadrant Engineering. This work will take three years and have four phases: Design (6 months), breadboard (12 months), build (12 months), flight test and validation (4 months).