An imaging algorithm for spaceborne high-squint L-band SAR based on time-domain rotation

For spaceborne high-squint L-band synthetic aperture radar (SAR), the long wavelength and high-squint angle result in strong coupling between the range and azimuth directions. In conventional imaging algorithms, linear range walk correction (LRWC) is commonly used to correct linear range cell migration which dominates the coupling. However, LRWC introduces spatial variation in the azimuth direction, limits the depth-of-azimuth-focus (DOAF) and affects the imaging quality. This article constructs a polynomial range model and develops a modified omega-k algorithm to achieve spaceborne high-squint L-band SAR imaging. The key to this algorithm is to rotate the two-dimensional (2-D) data after LRWC in the time domain by a proposed time-rotation (TR) operation that eliminates the DOAF degradation caused by LRWC. The proposed algorithm, which is composed of LRWC, bulk compression, TR, and modified Stolt interpolation, achieves well-focused results at a 1-m resolution and a swath of 4 km × 4 km at a squint angle of 45°

Radar Imaging in Challenging Scenarios from Smart and Flexible Platforms

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Mediterranean vegetation monitoring by remotely sensed data: LAI retrieval and vegetation trend analysis within two forested areas in southern italy

The object of the research was twofold: 1) The production of LAI (Leaf Area Index) distribution maps of two Mediterranean forested areas by means of satellite data, to this aim, high resolution IKONOS-2 and medium resolution LANDSAT-TM data were used, and their results compared, the choice to focus on LAI derives from the paramount role this vegetation biophysical, parameter plays in many climate and ecological models, since it is a control variable of important processes such as canopy radiation interception, evapotranspiration and net photosynthesis; 2) A trend analysis, within the same study areas, aimed at improving our understanding of Mediterranean forests response to changing climatic conditions. A yearly series of landsat satellite data and local climatic measurements over a time span of twenty years (1984-2005) were processed and compared in order to evaluate possible relationships between inter-annual variations of vegetation (as expressed by landsat-derived spectral vegetation indices) and related meteorological parameters

Aeronautical engineering: A continuing bibliography with indexes (supplement 239)

This bibliography lists 454 reports, articles, and other documents introduced into the NASA scientific and technical information system in April, 1989. Subject coverage includes: design, construction and testing of aircraft and aircraft engines; aircraft components, equipment and systems; ground support systems; and theoretical and applied aspects of aerodynamics and general fluid dynamics

Aeronautical engineering: A continuing bibliography with indexes (supplement 240)

This bibliography lists 629 reports, articles, and other documents introduced into the NASA scientific and technical information system in May, 1989. Subject coverage includes: design, construction and testing of aircraft and aircraft engines; aircraft components, equipment and systems; ground support systems; and theoretical and applied aspects of aerodynamics and general fluid dynamics

The Twenty-Fifth Lunar and Planetary Science Conference. Part 2: H-O

Various papers on lunar and planetary science are presented, covering such topics as: planetary geology, lunar geology, meteorites, shock loads, cometary collisions, planetary mapping, planetary atmospheres, chondrites, chondrules, planetary surfaces, impact craters, lava flow, achondrites, geochemistry, stratigraphy, micrometeorites, tectonics, mineralogy, petrology, geomorphology, and volcanology

Energy: A continuing bibliography with indexes

This bibliography lists 1169 reports, articles, and other documents introduced into the NASA scientific and technical information system from January 1, 1983 through March 31, 1983