The enhanced Polar Outflow Probe (ePOP) satellite is to be launched in 2007. One of the 8 instruments it will carry is a Radio Receiver Instrument (RRI) which is a passive radio receiver. The RRI will detect HF (High Frequency band 3 to 30 MHz) radio waves from ground transmitters, one of which is the Saskatoon SuperDARN radar. The modification of an HF radar wave as it propagates through the ionosphere to the satellite is the dominant scientific interest of this thesis. The modification of a radar wave as it propagates through the ionosphere can be used to characterize the ionosphere and reveal a better understanding of magnetoionic radar wave propagation. A ray tracing program has been written to determine characteristics of the wave, including the wave path and the full polarization state, at the satellite receiver. </p> As a confirmation of the ray tracing program abilities, data from a similar transionospheric experiment in 1978, the ISIS II satellite mission, has been analyzed and compared with simulated results. The ISIS II transionospheric experiment received radar signals from a transmitter (9.303 MHz) located in Ottawa, Canada. These signals were analyzed and it was noted that the signal periodically faded in and out both due to differential Faraday rotation effects (due to propagation through an ionized medium and reception on a single dipole antenna) and due to satellite spin rotation at rates up to 13 Hz. Also observed was a splitting of the received signal into Ordinary (O-mode) and Extraordinary (X-mode) components causing a delay between the arrival of the modes at ISIS II of up to 0.8 ms. Simulations have been carried out to model the radar wave propagation from the ground transmitter through the ionized medium of the ionosphere to the spacecraft. The modelled signal shows very similar trends to the observed signal. A linear regression analysis comparing observed to simulated fade rates gave values of slope equal to 1.07 and regression coefficient equal to 0.934. The regression analysis of mode delay gave values of slope equal to 1.14 and regression coefficient equal to 0.930. </p>Ray path modelling has also been simulated for the RRI experiment on ePOP. These simulations have been carried out for various ionospheric and satellite pass configurations. The expected fade rates, mode delays, and latitudinal range of received signal was determined from the simulated data in each case. The dependence of these characteristics on the various pass configurations are presented and discussed.

The enhanced Polar Outflow Probe (ePOP) satellite is to be launched in 2007. One of the 8 instruments it will carry is a Radio Receiver Instrument (RRI) which is a passive radio receiver. The RRI will detect HF (High Frequency band 3 to 30 MHz) radio waves from ground transmitters, one of which is the Saskatoon SuperDARN radar. The modification of an HF radar wave as it propagates through the ionosphere to the satellite is the dominant scientific interest of this thesis. The modification of a radar wave as it propagates through the ionosphere can be used to characterize the ionosphere and reveal a better understanding of magnetoionic radar wave propagation. A ray tracing program has been written to determine characteristics of the wave, including the wave path and the full polarization state, at the satellite receiver. </p> As a confirmation of the ray tracing program abilities, data from a similar transionospheric experiment in 1978, the ISIS II satellite mission, has been analyzed and compared with simulated results. The ISIS II transionospheric experiment received radar signals from a transmitter (9.303 MHz) located in Ottawa, Canada. These signals were analyzed and it was noted that the signal periodically faded in and out both due to differential Faraday rotation effects (due to propagation through an ionized medium and reception on a single dipole antenna) and due to satellite spin rotation at rates up to 13 Hz. Also observed was a splitting of the received signal into Ordinary (O-mode) and Extraordinary (X-mode) components causing a delay between the arrival of the modes at ISIS II of up to 0.8 ms. Simulations have been carried out to model the radar wave propagation from the ground transmitter through the ionized medium of the ionosphere to the spacecraft. The modelled signal shows very similar trends to the observed signal. A linear regression analysis comparing observed to simulated fade rates gave values of slope equal to 1.07 and regression coefficient equal to 0.934. The regression analysis of mode delay gave values of slope equal to 1.14 and regression coefficient equal to 0.930. </p>Ray path modelling has also been simulated for the RRI experiment on ePOP. These simulations have been carried out for various ionospheric and satellite pass configurations. The expected fade rates, mode delays, and latitudinal range of received signal was determined from the simulated data in each case. The dependence of these characteristics on the various pass configurations are presented and discussed.

Made available in DSpace on 2014-12-17T15:06:59Z (GMT). No. of bitstreams: 1 FernandoAP.pdf: 449536 bytes, checksum: b8b24355e1d20070bbb75016c3f426e4 (MD5) Previous issue date: 2005-12-15 / Coordena??o de Aperfei?oamento de Pessoal de N?vel Superior / The Lusiads is an epic poem, written by Lu?s de Cam?es, about the adventure of Vasco da Gama s trip and the history of Portugal. It's based on traditionals epics from the Greek and Roman poets, Homero and Virg?lio. Cam?es followes especially their structures. However, the poet insert modifications that divert his poem from parameters established by Arist?teles for the classic epic poems. These deviations are centered mainly on the narrative subject and in the point of view. We intend to show an analysis focused on digressions from The Lusiads, in which the author, himself or by tellers characters, narrates the story in order to make his complaints, reflections and exhortations. Besides, we present general aspects of Maneirismo predominant in these digressions how evidences of modernity of the poem; as one brief outlook about the poem's projection in time and around the world. These points are importants elements of consolidation of a universal permanence of The Lusiads. That's why they have had to read and to study by the centuries, according the vision of the epoch's spirit / Os Lus?adas, de Lu?s de Cam?es, s?o um poema ?pico, sobre a aventura da viagem de Vasco da Gama e hist?ria de Portugal, concebido com base nas epop?ias tradicionais dos poetas greco-romanos Homero e Virg?lio. Cam?es segue os modelos ?picos tradicionais, especialmente quanto ? estrutura. Entretanto, insere inova??es que desviam sua obra dos paradigmas do g?nero cl?ssico postulados por Arist?teles. Esses desvios se d?o principalmente pelas freq?entes irrup??es de elementos pr?prios da poesia l?rica na mat?ria ?pica, o que possibilita a participa??o do autor na obra, tanto no plano da enuncia??o, quanto no plano do enunciado, assim como a inser??o dos acontecimentos de seu presente hist?rico na narrativa, em contradi??o com as epop?ias tradicionais, cuja principal caracter?stica ? o distanciamento imensur?vel entre o tempo da narra??o e o tempo dos acontecimentos narrados. Este trabalho apresenta uma an?lise dos excursos, digress?es atrav?s das quais Cam?es assume a narra??o em primeira pessoa ou atrav?s de personagens-narradoras, para exprimir suas cr?ticas e exorta??es, queixas pessoais e sociais, e reflex?es existenciais. Apresenta ainda os aspectos predominantes da est?tica maneirista como ind?cios de modernidade do poema, bem como um breve panorama de sua proje??o no tempo e no espa?o. Esses elementos s?o preponderantes na caracteriza??o d'Os Lus?adas como obra permanente e universal, que os fazem ser lidos e estudados atrav?s dos s?culos, atualizando-se de acordo com cada estilo de ?poca