Title of Paper: Two Dimensional Synthetic Aperture Radiometer for Microwave Remote Sensing from Space

Principal Author: David Le Vine

Abstract: Aperture synthesis is an interferometric technique that has the potential to break through the barrier on resolution set by antenna size on future passive microwave instruments in space. The technique is an adaptation of a technology developed originally in radio astronomy in which the resolution of a single large aperture is obtained using pairs of small antennas and signal processing. The technique has been applied successfully to earth remote sensing using synthesis in one dimension (i.e. the L-band radiometer called ESTAR). The research being conducted here is to go the next step, to demonstrate the potential of aperture synthesis in both dimensions to meet future requirements of the research community.

An aircraft prototype instrument is being built. The instrument operates at L-band, uses digital correlation and an antenna that can be configured in several thinned arrays. It has been designed as a research tool to address engineering issues associated with the evolution of this technology to remote sensing from space. The choice of L-band 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. The instrument will be ready for initial test flights late in calendar 2001.