The GRACE mission consists of two identical satellites orbiting the Earth at an altitude of ∼500 km. Dual-frequency carrier-phase Global Positioning System (GPS) receivers are flying on both satellites. They are used for precise orbit determination and to time-tag the K-band ranging system used to measure changes in the distances between the two satellites. The satellites are also flying ultra-...

The EUMETSAT Satellite Application Facility on Support to Operational Hydrology and Water Management (H-SAF) was established by the EUMETSAT Council on 3 July 2005, starting activity on 1 September 2005. The Italian Meteorological Service serves as Leading Entity on behalf of twelve European member countries. H-SAF products include precipitation, soil moisture and snow parameters. Some products...

Wind products from geostationary satellites have been generated for over 20 years and are now used in numerical weather prediction systems. However, geostationary satellites are of limited utility poleward of the midlatitudes. This study demonstrates the feasibility of deriving high latitude tropospheric wind information from polar-orbiting satellites. The methodology employed is based on the a...

Remote sensing images from Earth-orbiting satellites are a potentially rich data source for monitoring and cataloguing atmospheric health hazards that cover large geographic regions. A method is proposed for classifying such images into hazard and nonhazard regions using the autologistic regression model, which may be viewed as a spatial extension of logistic regression. The method includes a n...

Power beaming from ground-based systems to space-based platforms has been proposed by a number of researchers as a means of delivering energy to orbiting satellites and stations. This paper considers the use of a seeded high-gain highefficiency Free-Electron Laser (FEL) amplifier based on a conventional linac as the source for power beaming. While the wall-plug efficiency of a single pass FEL i...

Digital cartography and automated mapping techniques based on GNSS positioning have transformed our relationship to the physical world. The convergence of these complementary technologies are supporting the growth of commercial and consumer location-based applications that benefit from the coupling of real-time information with maps that are more current than ever — at least in environments tha...

In the last 25 years, the explorations of the Voyager and Galileo missions have resulted in an entirely new view of the icy worlds orbiting the giant outer planets. These objects show a huge diversity in their characteristics, resulting from their formation histories, internal processes and interactions with their space environments. This paper will review the current state of knowledge about t...

I work on research problems centered around the theme of using automated planning systems as mediators for human-machine teams. Automated planning – a sub-field of Artificial Intelligence that deals with reasoning and the synthesis of plans for autonomous, intelligent agents – has seen many speedup and scalability advances in the past decades. Beginning with Shakey the robot and the STRIPS plan...

The ability to autonomously assemble large structures in space is desirable for the construction of large orbiting solar arrays, interplanetary spacecraft, or space telescopes. One technique uses freeying satellites to manipulate and connect elements of the structure. Since these elements are often exible and lack embedded actuators and sensors, the assembly robot must use its own actuators and...

Communication via satellite begins when the satellite is positioned in the desired orbital position. Ground stations can communicate with LEO (Low Earth Orbiting) satellites only when the satellite is in their visibility region. The visibility region is in fact the horizon plane. Because of natural barriers or too high buildings in urban areas, practical horizon plane differs from the ideal one...