Spelling suggestions: "subject:"artificial satellite"" "subject:"aartificial satellite""
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Electromechanical Modeling and Open-Loop Control of Parallel-Plate Pulsed Plasma Microthrusters with Applied Magnetic FieldsLaperriere, David Daniel. January 2005 (has links)
Thesis (M.S.) -- Worcester Polytechnic Institute. / Keywords: electric propulsion; applied magnetic fields; pulsed plasma thruster. Includes bibliographical references (p. 91-94).
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Microwave radiative transfer modeling of ice in the atmosphere a critical examination of cloud ice utilizing remote sensing /Zuiderweg, Adriaan T. Liu, Guosheng, January 2006 (has links)
Thesis (M. S.)--Florida State University, 2006. / Advisor: Guosheng Liu, Florida State University, College of Arts and Sciences, Dept. of Meteorology. Title and description from dissertation home page (viewed June 7, 2006). Document formatted into pages; contains v, 42 pages. Includes bibliographical references.
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Onboard image geo-referencing for LEO satellites /Van den Dool, Riaan. January 2005 (has links)
Thesis (MScIng)--University of Stellenbosch, 2005. / Bibliography. Also available via the Internet.
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Design & develop a satellite telemetry display applicationStuhlsatz, Kelly J. January 2006 (has links) (PDF)
Thesis (M.S.C.I.T.)--Regis University, Denver, Colo., 2006. / Title from PDF title page (viewed on May 24, 2006). Includes bibliographical references.
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Performance modeling and analysis of parallel processing and low earth orbit satellite communications systems /Raines, Richard A. January 1994 (has links)
Thesis (Ph. D.)--Virginia Polytechnic Institute and State University, 1994. / Vita. Abstract. Includes bibliographical references (leaves 199-209). Also available via the Internet.
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Aspect of a hardware-in-the-loop integrated test systemGrungxu, Lungile Leonard 03 1900 (has links)
Thesis (MScEng)--University of Stellenbosch, 2003. / ENGLISH ABSTRACT: A multiprocessor hardware-in-the-Ioop operating system was developed for the Integrated
Test System (ITS) and is aimed at implementing the ITS as a space emulation vehicle. The
thesis contains a study of satellite orbits, Kepler elements, geomagnetic fields and
communication protocol between the processors.
The system structure consists of an orbit generator, a core-operating system and is presented
with a study of the satellite sensors. In implementing the orbit propagator, there was a need
to pay special attention to the Halving algorithm, the Newton Raphson method and the True
Solution. These algorithms were used to calculate the true anomaly angle as a function of
eccentric anomaly. The communications protocol was tested and all the errors, with their
solutions, have been discussed.
A concept of a geomagnetic field emulator has also been included in the hardware-in-theloop
operating system. The evaluation of those aspects of the system and the conclusion are
presented together with recommendations. / AFRIKAANSE OPSOMMING: 'n multiprosesseerder Hardeware in die lus bedryfstelsel is ontwikkel vir 'n Geintegreerde
Toets Stelsel (ITS) en poog om die ITS te implementeer as 'n ruimte emulasie stelsel. Die
tesis behels die studie van sateliet wentelbane, Kepler wentelbaan elemente, geomagnetiese
velde en kommunikasie protokolle tussen die prosesseerders.
Die stelsel struktuur betaal uit 'n wentelbaan propageerder, 'n kern bedryfstelsel en 'n studie
van satelliet instrumentasie. As 'n deel van die implementering van die wentelbaan
propageerder is die halveer algoritme, Newton-Raphson algoritme en die ware oplossing as
numeriese oplossings ondersoek. Die kommunikasie protokol is getoets en foute ondersoek
en word bespreek.
'n konsep vir 'n Geomagnetiese veld emulasie word die hardeware in die lus stelsel ingesluit.
Die stelsel word ge-ewalueer en die gevolgtrekkings en aanbevelings gemaak.
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Precision propagation and orbit decay predication of low earth orbit satellitesOpperman, B. D. L. 12 1900 (has links)
Thesis (MScEng)--Stellenbosch University, 2003. / ENGLISH ABSTRACT: This study investigates the theory of precision satellite orbit propagation and satellite
lifetime prediction and lead to the development of two necessary software tools for
analysis in these fields. Precision propagation was achieved through the implementation
of Cowell's method of special perturbations, considering perturbations due to a 70x70
asymmetrical gravity field, atmospheric drag, Luni-Solar attraction and Solar radiation
pressure. The satellite's perturbed equations of motion were integrated utilizing a seveneighth
order Runge-Kutta-Fehlberg numerical integration procedure, limiting error
propagation by employing adaptive step size control. The MSlS-90 atmospheric density
model, providing for diurnal and semi-annual variations, was employed to determine
atmospheric density. Care was taken in the precision modelling of the motion of the
12000 equator and equinox. Propagation results for this test case proved to be superior to
the SGP4 propagator and a commercial package.
The long-term effects of Earth oblateness and atmospheric drag on a satellite's orbital
elements were investigated and applied to the orbit decay prediction problem. Orbit
decay was predicted by integrating the rates of change of the orbital elements due to Earth
oblateness and atmospheric drag. A semi-analytical technique involving Runge-Kutta
and Gauss-Legendre quadrature was employed in the solution process. Relevant software
was developed to implement the decay theory. Optimum drag coefficients, estimated
from drag analysis using precision propagation, were used in decay prediction. Two test
cases of observed decayed satellites were used to evaluate the theory. Results for both
test cases indicated that the theory fitted observational data well within acceptable limits. / AFRIKAANSE OPSOMMING: 'n Ondersoek is gedoen oor die teorie van presiesie satelliet-wentelbaan vooruitskatting
en satelliet-wentelbaanleeftyd afskatting en het gelei tot die ontwikkeling van twee
analiseprogramme vir gebruik in hierdie vakgebiede. Presiesie vooruitskatting is bereik
deur die gebruik van Cowell se metode van spesiale perturbasies, wat die invloed van 'n
nie-simmetriese 70x070 gravitasieveld, atmosferiese sleur, Son-Maan aantrekkingskragte
en druk van sonradiasie, in ag neem. Die satelliet se versteurde bewegingsvergelykings
is numeries ge-ïntegreer deur gebruik te maak van die sewe-agste orde Runge-Kutta-
Fehlberg metode wat fout-voortplanting inhibeer deur gebruik te maak van 'n aanpasbare
integrasiestaplengte. Die MSIS-90 atmosferies model, wat voorsiening maak vir dag-nag
en half-jaarlikse atmosferiese variasies, is gebruik vir die berekening van atmosferiese
digtheid. Sorg is gedra by die presiesie modellering van die beweging van die J2000
ekwator en ekwinokse. Resultate vir hierdie toetsgeval toon meer voortreflik te wees as
die SPG4 - en 'n kommersieël-beskikbare vooruitskatter.
Die langtermyn effekte van aard-afplatting en atmosferiese sleur op wentelbaanleeftyd is
ondersoek en toegepas op die wentelbaanverval-afskattingsprobleem. Wentelbaanverval
is bereken deur die integrasie van die tydsafgeleides van die wentelbaanelement onder
invloed van aard-afplatting en atmosferiese sleur. Vir die doel is 'n semi-analitiese
tegniek, wat gebruik maak van Gauss-Legendre kwadratuur en Runge-Kutta numeriese
integrasie, gebruik gemaak. Nodige rekenaar programmatuur is ontwi kkeI om die
vervalteorie te implimenteer. Optimale sleur-koëffisiënte is afgeskat deur van presiesie
wentelbaananalise gebruik te maak. Twee gevallestudies van bekende vervalde satelliete
is gebruik om die vervalteorie te evalueer. Resultate vir beide gevallestudies toon aan dat
eksperimentele resultate werklike vervaltye binne aanvaarbare limiete navolg.
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Pertubações orbitais devidas a maré terrestreSantos Nadjara dos [UNESP] January 2002 (has links) (PDF)
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santos_n_me_guara.pdf: 418632 bytes, checksum: 4f860ab8b61150a88cbfa52adf66369f (MD5) / Aplicações recentes de satélites artificiais, principalmente aquelas com finalidades geodinâmicas e altimétricas, requerem órbitas determinadas com bastante precisão. Em particular as marés terrestres alteram o geopotencial, causando perturbações adicionais no movimento do satélite. Tais perturbações, apesar de pequenas, têm sido detectadas. O presente trabalho trata de perturbações de órbitas de satélites artificiais devidas às marés terrestres. Ênfase é dada aos termos seculares e de longo período. O potencial foi desenvolvido em termos dos elementos orbitais e substituídos nas equações planetárias de Lagrange. Soluções analíticas estão apresentadas para casos particulares considerando os números de Love constantes. Um programa foi elaborado, e colocado a disposição do usuário, permitindo calcular, para um dado satélite, a amplitude e o período dos termos perturbadores mais significativos. / Recent applications of artificial satellites, mainly those of geodynamics and altimetric purposes, requires high precise orbit determination. Particularly, Earth tides change the geopotencial causing additional perturbation in the satellite orbital motion. Inspite of being very small such perturbations, has been detected. The present work concerns about orbit perturbations of artificial satellites due do terrestrial tides. Treatment of secular and long period terms is emphasized. The potencial was developed in terms of the orbital elements and substituted in the Lagrange equations. Analytical solutions are presented for particular cases considering the Love’s number as constant. A computer enabling to compute, for a given satellite, the amplitude and period of the more significant disturbing terms, was constructed and it is, at the disposal for users.
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On some aspects of dynamics, modelling, and attitude analysis of satellitesMarandi, Said Rashed January 1988 (has links)
The thesis identifies several limitations in the modelling and attitude stability analysis of two classes of spacecraft: rigid and flexible satellites. Attractive methods
are proposed which promise to have far reaching consequences in spacecraft dynamics. These alternatives, developed based on techniques of differential equations,
classical mechanics, and differential topology, are indicated below.
(a) An Alternate Transition from the Lagrangian of a Satellite to Equations of Motion
The classical procedure requires the Lagrangian to be expressed in terms of the corresponding generalized coordinates of the problem. This requirement significantly
complicates the derivation of the equations of motion through an introduction
of a set of librational generalized coordinates, which is strictly not a part of the dynamical system. Using the Lagrangian in the natural variables (angular velocity, direction cosines, and vibrational coordinates), one develops a procedure for derivation of equations of motion without an a priori choice of rotational generalized coordinates. For the case of a satellite with two flexible plate-type appendages, for example, the approach reduced the formulation time to one-third.
(b) Synthesis and Depiction of Rotational Motion of Satellites and Robots
The rotational coordinates in use for numerical prediction of orientation of a satellite are either singular or redundant. Furthermore, they lack a convenient visual interpretation. A new set of coordinates is proposed and an associated representation is developed which avoids these limitations. The procedure is applied to represent and integrate numerically the librational response of the flexible satellite mentioned in (a).
(c) Resolution of Attitude Stability of Delp Satellites
The development here tackles a long outstanding problem in the area of attitude stability of satellites. The resolution of this problem through normalization of the Hamiltonian leads to a better appreciation of stability associated with the class of gravity gradient structures such as the proposed Space Station. / Applied Science, Faculty of / Mechanical Engineering, Department of / Graduate
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Link budget design software for satellite communicationsMerritt, Ervin A. 26 January 2010 (has links)
Master of Engineering
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