Made available in DSpace on 2014-06-11T19:22:25Z (GMT). No. of bitstreams: 0 Previous issue date: 2007-04-24Bitstream added on 2014-06-13T19:06:24Z : No. of bitstreams: 1 magnajr_jp_me_prud.pdf: 1562358 bytes, checksum: 707020e37c54b516d7377926b9cefee2 (MD5) / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) / Os avanços tecnológicos nos métodos de posicionamento, sobretudo os sistemas de posicionamento por satélite, fizeram com que diversos países atualizassem e/ou revisassem suas estruturas geodésicas fundamentais. Na busca de explorar a total potencialidade das novas tecnologias, as principais mudanças convergiram para a adoção de referenciais geocêntricos, de caráter global e cuja origem coincide com o centro de massa da Terra. A atualização de uma rede geodésica implica na mudança de coordenadas e, consequentemente, alteração da geometria da rede, evidenciando as distorções nela existentes. Para manter a integridade e topologia da rede geodésica é necessário que se proceda a uma modelagem das distorções. Neste contexto, este trabalho apresenta uma metodologia de modelagem de distorções entre realizações de sistemas de referência geodésicos, baseada na utilização de grades regulares. Amplamente utilizada, a modelagem baseada em grades é uma forma padronizada de se realizar a conversão entre referenciais sem a necessidade de aplicação de modelos complexos por parte dos usuários. Nessa dissertação, foram geradas grades de distorção com diferentes espaçamentos, cobrindo todo o território brasileiro, para a modelagem das distorções entre as redes SAD 69 (realização de 1996) e SIRGAS 2000. A geração e aplicação das grades esta pautada no desenvolvimento de aplicativos computacionais com utilização do método de Shepard na geração da grade e da função bilinear na interpolação das distorções a partir dos pontos da grade. A metodologia foi avaliada através de estações de teste, onde os resultados mostraram-se promissores. Nos melhores casos, houve redução de aproximadamente 50% no erro médio quadrático das coordenadas após a modelagem com um indicador médio de precisão de 0,179m. / The technological advances in the positioning methods, mainly in the satellite positioning systems conduced several countries to update and review their fundamental geodetic networks. In order to explore the full potential of these new technologies, the main changes converged to the adoption of geocentric reference systems, that are global and whose origin coincides with the Earth mass center. The geodetic network update implies in coordinate changes and, consequently, the network geometry changes, evidencing the existent distortions. To preserve the data set integrity and topology it is required a modeling of the distortions. In this context, this work presents a distortion modeling methodology between reference frames based on regular grids. Widely used, the modeling based on grids is a standardized and less complex way to accomplish the conversion between frames without the necessity to apply rigorous models by the user. In this research, distortion grids were generated with different sizes and covering all Brazilian s territory to model the distortion between the SAD 69 (1996) and SIRGAS 2000 frames. The grid generation and application are based on computational software development by the use of the Shepard s method in the grid generation and the bilinear function in the distortion interpolation from the grid points. The methodology was evaluated through test stations where the results were promising. In the best cases, the root mean squared error in the coordinates was reduced 50% after the modeling with an average precision indicator of 0,179m.

Orientador: Paulo de Oliveira Camargo / Orientador: Maurício Galo / Banca: João Carlos Chaves / Banca: Leonardo Castro de Oliveira / Resumo: Os avanços tecnológicos nos métodos de posicionamento, sobretudo os sistemas de posicionamento por satélite, fizeram com que diversos países atualizassem e/ou revisassem suas estruturas geodésicas fundamentais. Na busca de explorar a total potencialidade das novas tecnologias, as principais mudanças convergiram para a adoção de referenciais geocêntricos, de caráter global e cuja origem coincide com o centro de massa da Terra. A atualização de uma rede geodésica implica na mudança de coordenadas e, consequentemente, alteração da geometria da rede, evidenciando as distorções nela existentes. Para manter a integridade e topologia da rede geodésica é necessário que se proceda a uma modelagem das distorções. Neste contexto, este trabalho apresenta uma metodologia de modelagem de distorções entre realizações de sistemas de referência geodésicos, baseada na utilização de grades regulares. Amplamente utilizada, a modelagem baseada em grades é uma forma padronizada de se realizar a conversão entre referenciais sem a necessidade de aplicação de modelos complexos por parte dos usuários. Nessa dissertação, foram geradas grades de distorção com diferentes espaçamentos, cobrindo todo o território brasileiro, para a modelagem das distorções entre as redes SAD 69 (realização de 1996) e SIRGAS 2000. A geração e aplicação das grades esta pautada no desenvolvimento de aplicativos computacionais com utilização do método de Shepard na geração da grade e da função bilinear na interpolação das distorções a partir dos pontos da grade. A metodologia foi avaliada através de estações de teste, onde os resultados mostraram-se promissores. Nos melhores casos, houve redução de aproximadamente 50% no erro médio quadrático das coordenadas após a modelagem com um indicador médio de precisão de 0,179m. / Abstract: The technological advances in the positioning methods, mainly in the satellite positioning systems conduced several countries to update and review their fundamental geodetic networks. In order to explore the full potential of these new technologies, the main changes converged to the adoption of geocentric reference systems, that are global and whose origin coincides with the Earth mass center. The geodetic network update implies in coordinate changes and, consequently, the network geometry changes, evidencing the existent distortions. To preserve the data set integrity and topology it is required a modeling of the distortions. In this context, this work presents a distortion modeling methodology between reference frames based on regular grids. Widely used, the modeling based on grids is a standardized and less complex way to accomplish the conversion between frames without the necessity to apply rigorous models by the user. In this research, distortion grids were generated with different sizes and covering all Brazilian’s territory to model the distortion between the SAD 69 (1996) and SIRGAS 2000 frames. The grid generation and application are based on computational software development by the use of the Shepard’s method in the grid generation and the bilinear function in the distortion interpolation from the grid points. The methodology was evaluated through test stations where the results were promising. In the best cases, the root mean squared error in the coordinates was reduced 50% after the modeling with an average precision indicator of 0,179m. / Mestre

The new generation of giant ground-based telescopes will see their first light this decade. These state-of-the-art facilities will significantly surpass the resolving power of modern space-based observatories such as the James Webb telescope, thanks to their enormous aperture size and adaptive optics (AO) facilities. Without AO, atmospheric turbulence would degrade the image quality of these enormous telescopes to that of a 50 cm amateur one. These extremely large telescopes (ELTs) will further benefit from a particular branch of AO called multi-conjugate adaptive optics (MCAO), which provides an extremely high resolving power over a much wider field of view as compared to classical AO systems. The design and fabrication of such systems, as well as their optimal use for science operation, pose a great challenge as they are an order of magnitude more complicated than current AO systems. To face such a challenge, the combined knowledge of MCAO system design and fabrication, working in tandem with scientific insights into new astronomy science cases, is an extremely valuable and essential pairing. This thesis is an effort to not only contribute to the design and fabrication of ELT MCAO facilities, but also provide guidance on the optimal method to utilize these giant telescopes to achieve unprecedented astrometric measurements. On the instrumentation side, in partnership with the National Research Council of Canada's - Herzberg Astronomy and Astrophysics Institute as well as W.M. Keck Observatory in Hawaii, I was involved in the design and fabrication of a cutting edge new wavefront sensor, which is the eye of an AO system. I performed opto-mechanical design and verification studies for components of the Keck infrared pyramid wavefront sensor (IR-PWFS) as well as the Keck Planet Imager and characterizer (KPIC) instrument, which have both been commissioned and are in science operation. Furthermore, I designed the alignment plan and participated in the modification and alignment operation of a few components on the Keck II adaptive optics bench on the summit of Mauna Kea. To pave the way for the design verification of future MCAO systems for ELTs, I proposed a new method for an old challenge in the path of AO system design and verification: a flexible method for precise intensity pattern injection into laboratory AO benches. AO benches are the backbone of instrument design and modeling. One of the challenges especially important for the future generation of MCAO systems for ELTs is the verification of the effect of shadowed regions on the primary mirror. During my PhD, I successfully demonstrated the feasibility of a new proposed method to accurately model the telescope pupil. This work was done in partnership with the Laboratoire d'Astrophysique de Marseille (LAM) in France. The method I developed at LAM will be implemented in the AO Lab at NRC Herzberg Astronomy and Astrophysics. As an observational astronomer, I focused on developing methods for making optimal astrometric measurements with MCAO-enabled telescopes. The expected unparalleled astrometric precision of ELTs comes with many unprecedented challenges that if left unresolved, would jeopardize the success of these facilities as they would not be able to reach their science goals. I used observations with the only available MCAO system in science operation, the Gemini MCAO system on the 8-meter Gemini South telescope in Chile, to develop and verify a pipeline specifically designed for very high-precision astrometric studies with MCAO-fed imagers. I successfully used the pipeline to provide the precise on-sky differential distortion of the Gemini South telescope and its MCAO facilities by looking deep into the core of globular cluster NGC~6723. Using this pipeline, I produced high quality proper motions with an uncertainty floor of $\sim 45$\,$\mu$as~yr$^{-1}$ as well as measured the proper motion dispersion profile of NGC~6723 from a radius of $\sim 10$ arcseconds out to $\sim 1$\,arcminute, based on $\sim 12000$ stars. I also produced a high-quality optical-near-infrared color magnitude diagram which clearly shows the extreme horizontal branch and main-sequence knee of this cluster. / Graduate

Cílem předkládané diplomové práce je pomocí lícování obrazů přesně popsat distorzní pole pro následné odstranění geometrické distorze. Snímky zkreslené geometrickou distorzí pochází z prozařovacího elektronového mikroskopu. První část práce se zabývá zejména teorií spojenou s elektronovou mikroskopií, vznikem geometrické distorze a samotnou obrazovou registrací s důrazem na intenzitní flexibilní metody lícování. Ve druhé části je pak představena vytvořená metoda pro modelování geometrické distorze a lícování obrazů postižených slabou geometrickou distorzí. Vyvinutá metoda je následně otestována na testovacích i reálných datech a srovnána s existujícími popsanými metodami pro obrazovou registraci (například open-source softwarem Elastix).