Paden J.,Vexcel Corporation |
Akins T.,Garmin |
Dunson D.,United Road Services |
Allen C.,University of Kansas |
Gogineni P.,University of Kansas
Journal of Glaciology | Year: 2010
Information on bed topography and basal conditions is essential to developing the nextgeneration ice-sheet models needed to generate a more accurate estimate of ice-sheet contribution to sea-level rise. Synthetic aperture radar (SAR) images of the icebed can be analyzed to obtain information on bed topography and basal conditions. We developed a wideband SAR, which was used during July 2005 to perform measurements over a series of tracks between the GISP2 and GRIP cores near Summit Camp, Greenland. The wideband SAR included an eight-element receive-antenna array with multiple-phase centers. We applied the MUltiple SIgnal Classification (MUSIC) algorithm, which estimates direction of arrival signals, to single-pass multichannel data collected as part of this experiment to obtain fine-resolution bed topography. This information is used for producing fineresolution estimates of bed topography over a large swath of 1600 m, with a 25m posting and a relative accuracy of approximately 10m. The algorithm-derived estimate of ice thickness is within 10m of the GRIP ice-core length. Data collected on two parallel tracks separated by 500m and a perpendicular track are compared and found to have difference standard deviations of 9.1 and 10.3m for the parallel and perpendicular tracks, respectively.
Raney R.K.,Johns Hopkins University |
Spudis P.D.,Lunar and Planetary Institute |
Bussey B.,Johns Hopkins University |
Crusan J.,NASA |
And 9 more authors.
Proceedings of the IEEE | Year: 2011
The two mini-radio-frequency (mini-RF) radars flown in near-polar lunar orbits (on Chandrayaan-1 and the Lunar Reconnaissance Orbiter) were the first of their kind, hybridpolarimetric. This new paradigm transmits circular polarization, and receives coherently on orthogonal linear polarizations. The resulting data support calculation of the 2 × 2 covariance matrix of the backscattered field, from which follow the four Stokes parameters. These are the basis of science products from the observations, which include images that are traditional in radar astronomy, as well as polarimetric decompositions. The instruments all have mass less than 15 kg, antenna areas of about 1 m 2, and modest power and spacecraft accommodation requirements. Data quality and instrument characteristics suggest that hybrid polarity is highly desirable for future exploratory radar missions in the Solar system. © 2010 IEEE.
Beran B.,Microsoft |
Van Ingen C.,Microsoft |
Fatland D.R.,Vexcel Corporation
Concurrency Computation Practice and Experience | Year: 2010
The combination of low-cost in situ sensors, internet connectivity, and commodity computing is changing earth science research. This unprecedented data availability is enabling science synthesis; studies that span disciplines, bridge local field, modeling and remote sensing methodologies and/or span local, regional, and global scales. Data discovery, retrieval, and heterogeneity act as cyberinfrastructure barriers to synthesis. Much of the available data is discovered by serendipity or word of mouth from independent, disconnected nodes with different interfaces and semantics. Before scientific analysis, data must be harmonized to a common understandable format. As the number of publishers increase, particularly when the publishers are small groups, this problem can only worsen. We have been developing SciScope (www.sciscope.org), a search tool that aggregates data set information and presents a simple map-based interface across diverse data publishers. SciScope unites data catalog, semantic, structural and syntactic mediation, and Geographical Information Systems (GIS) functions. The current catalog contains 1.7 million observation sites from five different sources in the United States and Australia. SciScope encourages participatory science. Data consumers can find and retrieve data sets simply as well as annotate data sets. Data contributors can register and upload data sets as well as extend the semantic mediation to enable richer data searches. SciScopes can be federated to bridge between science communities that may not be willing or able to share a single catalog. Copyright © 2010 John Wiley & Sons, Ltd.