Prof. Hysell of Cornell University

Abstract: Methods for probing the Earth's ionosphere using different classes of radar are reviewed. Following an initial survey, radar imaging methods are examined in detail. A new multiple-input, multiple output (MIMO) aperture synthesis imaging approach being applied at the Jicamarca Radio Observatory near Lima, Peru, is discussed. MIMO methods increase the number of distinct interferometry baselines available for imaging as well as the effective size of the synthetic aperture. The particular method employed here involves time-division multiplexing or time diversity to distinguish pulses transmitted from different parts of the array. The method comes at the cost of a large increase in computation time and complexity and a reduced signal-to-noise ratio. The signal-processing details and the trade space involved in image optimization are described.

Biography:

David Hysell earned his Ph.D. from Cornell in 1992. Hysell investigates ionospheric plasma physics with a focus on plasma instabilities, ionospheric irregularities, and their effects on radio wave propagation. Communication outages caused by ionospheric irregularities are a central component of the National Space Weather Program. The instabilities of interest are found in the equatorial and auroral electrojets, in the midlatitude E region ionosphere, and in equatorial and midlatitude spread F. The research is both experimental and theoretical and has a substantial computational component. An important research tool for studying the equatorial ionosphere is the Jicamarca Radio Observatory near Lima, Peru, the world’s largest radar. In the spring of 2005, Hysell became the PI for the NSF Cooperative Agreement that supports Jicamarca.

Email:

Address:Snee Hall, Room 3114 and Room 2116, Cornell University, Ithaca, New York, United States, 14850