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37 articles for “Satellites”
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Research ArticleOpen accessIn the abstractFixed-Star Tracking Attitude Control of Spacecraft Using Single-Gimbal Control Moment GyrosSangwon Kwon, Yuki Tani, Hiroshi Okubo, Takashi ShimomuraProblem statement: A cluster of small-sized Single-Gimbal Control Moment Gyros (SGCMGs) is proposed as an attitude control actuator for high-speed maneuver of small satellites. There exists a singularity problem what is peculiar to the CMG system. Approach: This study presented a simple singularity avoidance steering law using the Singular Value Decomposition (SVD) algorithm. Results: Capability of the present steering method … …American Journal of Engineering and Applied Sciences, Vol. 3, Issue 1 · 31 Mar 2010 · 7,978 accessesView PDFCite
Research ArticleOpen accessIn the abstractInvestigation of Vegetation Dynamics using Long-Term Normalized Difference Vegetation Index Time-SeriesTamara Bellone, Piero Boccardo, Francesca PerezProblem statement: The Normalized Difference Vegetation Index (NDVI) is the most extensively used satellite-derived index of vegetation health and density. Since climate is one of the most important factors affecting vegetation condition, satellite-derived vegetation indexes have been often used to evaluate climatic and environmental changes at regional and global scale. The proposed study attempted to investigate the temporal vegetation dynamics … …American Journal of Environmental Sciences, Vol. 5, Issue 4 · 31 Aug 2009 · 7,404 accessesView PDFCite
Research ArticleOpen accessIn the abstractIonospheric Total Electron Content Response to the December 26, 2004 North Sumatra EarthquakeA. Abdullah, A. F.M. Zain, M. H. Jusoh et al.Problem statement: Ionospheric precursors of earthquake have been studied by scientists and seismologists. This study aims at examining the relationship between the ionosphere and earthquake precursors. The effects of the anomalous electric field that penetrates the ionosphere on the electron concentration can be measured experimentally. This study reports on the variability of the Total Electron Content (TEC) during the December … …American Journal of Applied Sciences, Vol. 6, Issue 4 · 30 Apr 2009 · 7,908 accessesView PDFCite
Research ArticleOpen accessIn the abstractActive Fire Monitoring with Level 1.5 MSG Satellite ImagesAbdelatif Hassini, Farid Benabdelouahed, Noureddine Benabadji, Ahmed Hafid BelbachirThe first of the new generation of Meteosat satellites, known as Meteosat Second Generation (MSG-1), was launched in August 2002. As with the current Meteosat series, MSG is spin-stabilized and capable of greatly enhanced Earth observations. The satellite’s 12-channel imager, known formally as the Spinning Enhanced Visible and Infrared Imager (SEVIRI), observes the full disk of the Earth with an … …American Journal of Applied Sciences, Vol. 6, Issue 1 · 31 Jan 2009 · 8,130 accessesView PDFCite
Research ArticleOpen accessIn the abstractLeveling Process of Total Electron Content (TEC) Using Malaysian Global Positioning System (GPS) DataY. Norsuzila, M. Abdullah, M. IsmailThe signals from the satellites of the Navstar Global Positioning System (GPS) travel through the earth's ionosphere on their way to GPS receivers. However, ionospheric delay is one of the main sources of error in GPS. The magnitude of the ionospheric delay is influenced by the Total Electron Content (TEC) along the radio wave path from a GPS satellite to … …American Journal of Engineering and Applied Sciences, Vol. 1, Issue 3 · 30 Sep 2008 · 7,762 accessesView PDFCite
Research ArticleOpen accessIn the abstractOOST: An Object Oriented Tool for Satellite Orbit DesignA. A. Salem, M. Zaki, A. A. WahdanIn this study the problems of satellite orbit design and simulation are tackled and an object oriented satellite tool OOST is developed. The tool with its three main modules enables the user to plan and design different satellite missions. It performs all orbital calculations needed, simulates the target orbit and performs analysis on the current active satellite(s). The simulation module … …American Journal of Applied Sciences, Vol. 2, Issue 4 · 30 Apr 2005 · 7,211 accessesView PDFCite
Research ArticleOpen accessIn the abstractArchitecture for Combined Energy and Attitude Control SystemIbrahim Mustafa Mehedi, Renuganth Varatharajoo, Harlisya Harun, Mohd Nizam FilipskiCombining the energy and attitude control system is a feasible technology for small satellites to improve the space missions. In this Combined Energy and Attitude Control System (CEACS) a double rotating flywheel is used to replace the conventional battery for energy storage as well as to control the attitude of an earth oriented satellite. Each flywheel is to be controlled … …American Journal of Applied Sciences, Vol. 2, Issue 1 · 31 Jan 2005 · 6,404 accessesView PDFCite