Thesis (M.S.)--Wisconsin. / Includes bibliographical references (leaves 87-88).

Thesis (M.S.)--University of Wisconsin--Madison, 1967. / eContent provider-neutral record in process. Description based on print version record. Includes bibliographical references.

Thesis (M.S.)--Montana State University--Bozeman, 2005. / Typescript. Chairperson, Graduate Committee: David M. Klumpar. Includes bibliographical references (leaves 220-221).

Thesis (Ph. D.)--University of Washington, 2006. / Vita. Includes bibliographical references (leaves 149-172).

Thesis (Ph. D.)--University of Hawaii at Manoa, 2001. / Includes bibliographical references (leaves 180-195). Also available on microfiche.

Η διπλωματική εργασία μελετά τις έννοιες των Δορυφορικών συστημάτων καθώς και τα βασικά μέρη από τα οποία αποτελούνται. Δίνει γενικές πληροφορίες για τη χρήση τους, τον τρόπο λειτουργίας τους και τις σύγχρονες εφαρμογές τους. Ξεκινώντας απο τον σταθμό του δορυφόρου και αναλύοντας στην συνέχεια τους επίγειους σταθμους εκπομπής και λήψης του σήματος γίνεται αναλυτική περιγραφή της διαδρομής του σήματος. Στα τελευταία κεφάλαια γίνεται περιγραφή και χρησης της μαθηματικής-φυσικής εξίσωση του Budget Link για συλλογή πληροφοριών και εξαγωγή βασικών συμπερασμάτων για τον τροπο που επιδρούν οι διάφοροι παράγοντες της εξίσωσης στο μεταδιδόμενο σήμα μέσω της προσομοίωσης του δορυφορικού καναλιού σε περιβάλλον πολυμέσων. / This dissertation investigates the principles of Satellite systems and its components. It reports on their use, function and contemporary applications. Focusing on the route of the signal, the first part informs on the station of the satellite, while the second part analytically presents the terrestrial stations of emission and reception of signal. Finally, through both mathematical and physic-related assessment of the Budget-Link equation, conclusions arise on the determinant factors of the equation and their corresponding influence on the route of the signal through the simulation of the satellite channel on media environment.

Στόχος της παρούσας εργασίας είναι η υλοποίηση ενός αλγορίθμου για την ανίχνευση και παρακολούθηση του δορυφορικού σήματος υπό διάφορες συνθήκες διάδοσης στο κανάλι. Αρχικά αναλύεται η δομή ενός δορυφορικού συστήματος επικοινωνιών και περιγράφονται τα σημαντικότερα στοιχεία του τόσο στο επίγειο όσο και στο διαστημικό τμήμα. Στη συνέχεια παρουσιάζεται το περιβάλλον του καναλιού μέσα στο οποίο γίνεται η διάδοση των ηλεκτρομαγνητικών κυμάτων και αναλύονται οι σημαντικότεροι παράγοντες εξασθένισης και αλλοίωσης του σήματος. Τέλος, γίνεται αναφορά στα σημαντικότερα υπάρχοντα συστήματα παρακολούθησης των δορυφορικών κεραιών σε ένα από τα οποία βασίστηκε και ο αλγόριθμος παρακολούθησης που δημιουργήθηκε μέσω του προγράμματος Matlab. / The main purpose of this thesis is the development of a basic algorithm capable of tracking the satellite signal under various propagation scenarios. At first, an analytical presentation of both earth and the space segment of the satellite system is being held. Afterwards, the basic elements of the satellite link are explained, as well as their negative effects on the radio-wave propagation mechanism. Finally, a brief reference on the most used antenna tracking systems is made, before we move on to the development of our own step-tracking algorithm in order to simulate the antenna tracking procedure under realistic transmission conditions.

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.

No description available.

[pt] A propagação das ondas eletromagnéticas em freqüências superiores a 10 GHz sofre uma degradação causada pela chuva. O efeito da precipitação é particularmente importante em regiões de clima tropical e equatorial onde se observam as mais elevadas taxas de precipitação. Este trabalho apresenta resultados de um programa de medidas de propagação realizado no Brasil, desde 1987, utilizando radiômetros operando na faixa de 12 GHz e pluviômetros. A partir dos dados de atenuação e taxa de precipitação medidos simultaneamente em 6 locais em diferentes regiões do Brasil, durante pelo menos 1 ano, que forneceram distribuições estatísticas de 10 anos em 6 estações, foi desenvolvido um modelo de previsão da atenuação causada pela chuva em enlaces satélite. Apresenta-se ainda resultados do estudo do comportamento dinâmico da atenuação por chuvas. / [en] The rain attenuation is a major impairment on the radio wave propagation at frequencies above 10 GHz. The rain effect is particularly important in tropical and equatorial regions which experience the most severe rain rates. This work presents results of the propagation measurement campaign conducted in Brazil since 1987, using radiometers, operating at the frequency of 12 GHz, and raingauges. A rain induced attenuation prediction model for satellite- Earth links was developed from the data of 10 year- stations measured in Brazil. The results of the dynamic behaviour of rain attenuation are also presented.