59 resultados para Satelites geodesicos
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Pós-graduação em Agronomia - FEIS
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Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)
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Pós-graduação em Física - FEG
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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)
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Pós-graduação em Agronomia (Energia na Agricultura) - FCA
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Pós-graduação em Agronomia (Energia na Agricultura) - FCA
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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)
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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)
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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)
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Pós-graduação em Física - FEG
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Pós-graduação em Física - FEG
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The aims of this work are to analyze the direct solar radiation pressure torque (TPRS) in the rotational motion of spin-stabilized artificial satellites, to numerically implement these solutions and to compare the results with real data of the Brazilian Satellite Data Collection – SCD1 and SCD2, supplied by INPE. The mathematical model for this torque is determined for a cylindrical satellite, and the components of this torque are determined in a fixed system in the satellite. An analytical solution for the spin motion equations is proposed, in which TPRSD does not affect the spin velocity of the satellite. Two approaches are adopted in the numerical implementation of the developed theory: the first one considers the proposed theory and the second introduces a variation in the spin velocity based on its real variation. The results obtained indicate that the solar radiation pressure torque has little influence in the right ascension and declination axis of rotation due to the small dimension of the satellite and altitude in which it is found. To better validate the application of the presented theory, the angular deviation of the spin axis and solar aspect angle were also analyzed. The comparison of the results of the approaches conducted with real data show good precision in the theory, which can be applied in the prediction of the rotational motion of the spin-stabilized artificial satellites, when others external torques are considered besides the direct solar radiation pressure torque
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The Brazilian Environmental Data Collection System (Sistema Brasileiro de Coleta de Dados Ambientais - SBCDA) has been providing reliable information regarding the monitoring of the Brazil environment to INPE (Instituto Nacional de Pesquisas Espaciais) and many Non-governmental organizations (NGO). This system is composed of a large number of Data Collection Plataforms (DCP), in charge of sending local data signals to satellites. Then the satellites automatically redirect each signal to reception centers located at INPE. Nowadays the SBCDA has been operating under the control of three satellites. It is important to mention that two of these satellites have already expired their life span around ten years ago. A strategy to keep the SBCDA operational is to develop a low cost satellite that involves Brazilian Universities and Public Institutions. This graduation work aims to design and simulate a signal conditioning module that enables the collection of a satellite status data, and then sending it to an onboard computer
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The transportation of oil through polyducts implies a concern related to safety and environmental impacts they may cause, especially when exposed to risks that affect their integrity. Among the various anthropogenic activities included in this scenario, mining can aggravate, increase the risks and degrade the environment. Since these polyducts go through significant extensions, remote sensing has great applicability as a tool for data acquisition. For this, change detection techniques were used to monitor mining activities in a defined study area in the state of Rio de Janeiro, along the duct ORBEL. The characterization of the study area and the mining activities were developed through bibliographical data. The satellite images processing and the application of change detection technique were performed in two scenes for the years 2002 and 2010. The growth in the mining area was about 6.67 times and it was possible to identify types of extraction involved which can represent direct risks to the pipeline
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The aim of this work is to analyze the stability of the rotational motion’s artificial satellite using the Routh Hurwitz Algorithm (CRH) and the quaternions to describe the satellite’s attitude. This algorithm allows the investigation of the stability of the motion using the coefficients of the characteristic equation associated with the equation of the rotational motion in the linear form. The equations of the rotational motion are given by the four cinematic equations for the quaternion and the three equations of Euler for the spin velocity’s components. In the Euler equations are included the components of the gravity gradient torque (TGG) and the solar radiation torque (TRS). The TGG is generated by the difference of the Earth gravity force direction and intensity actuating on each satellite mass element and it depends on the mass distribution and the form of the satellite. The TRS is created by changing of the linear momentum, which happens due to the interactions of solar photons with the satellite surface. The equilibrium points are gotten by the equation of rotational motion and the CRH is applied in the linear form of these equations. Simulations are developed for small and medium satellites, but the gotten equilibrium points are not stable by CRH. However, when some of the eigenvalues of the characteristic equation are analyzed, it is found some equilibrium points which can be pointed out as stables for an interval of the time, due to small magnitude of the real part of these eigenvalue