No description available.

This diploma thesis deals with the Precise Point Positioning (PPP) method in various variants. The thesis describes the theoretical foundations of the PPP method and the most important systematic errors that affect accuracy. The accuracy of the PPP method was evaluated using data from the permanent GNSS station CADM, which is part of the AdMaS research center. Data of the period 2018 – 2019 were processed. The results of combinations of different GNSS and the results of different observation periods were compared. Finally, the accuracy was verified at 299 IGS GNSS stations.

Tato diplomová práce si klade za cíl návrh hybridního lokalizačního zařízení, které je schopno lokalizace uvnitř i vně budov. Lokalizace uvnitř budov je dosažena pomocí technologie Ultra Wideband a venkovní lokalizace je provedena pomocí kombinace technologie RTK GNSS a PPP pomocí open - source softwaru zvaného RTKLIB. První část textu se zaměřuje na vysvětlení používaných technologií a výběr nejpřesnější technologie pro venkovní lokalizaci. Druhá část se zaměřuje ma vývoj potřebného hardware a software finálního zařízení a na integraci systému pro venkovní lokalizaci do systému pro lokalizaci vnitřní. Výstupem práce je plně funkční zařízení, které je schopné plynulé lokalizace uvnitř i vně budov. Funčnost celého zařízení je dokázána na finálních testech uskutečněných ve vnitřních i venkovních prostorách. Na závěr také práce zmiňuje možná vylepšení celého zařízení, která mohou být v budoucnu provedena.

Orientador: João Francisco Galera Monico / Resumo: A tecnologia Global Navigation Satellite Systems (GNSS) tem sido amplamente utilizada em posicionamento, desde as aplicações cotidianas (acurácia métrica), até aplicações que requerem alta acurácia (poucos cm ou dm). Quando se pretende obter alta acurácia, diferentes técnicas devem ser aplicadas a fim de minimizar os efeitos que o sinal sofre desde sua transmissão, no satélite, até sua recepção. O sinal GNSS ao se propagar na atmosfera neutra (da superfície até 50 km), é afetado por gases hidrostáticos e vapor d’água. A variação desses constituintes atmosféricos causa uma refração no sinal que gera um atraso. Esse atraso pode ocasionar erros na medida de no mínimo 2,5 m (zenital) e superior a 25 m (inclinado). A determinação do atraso na direção inclinada (satélite-receptor) de acordo com o ângulo de elevação é realizada pelas funções de mapeamento. Uma das técnicas para o cálculo do atraso é o traçado de raio (ray tracing). Essa técnica permite mapear o caminho real que o sinal percorreu e modelar a interferência da atmosfera neutra sobre esse sinal. Diferentes abordagens podem ser usadas para obter informações que descrevem os constituintes da atmosfera neutra. Dentre as possibilidades pode-se citar o uso de medidas de radiossondas, modelos de previsão do tempo e clima (PNT), medidas GNSS, assim como modelos teóricos. Modelos de PNT regionais do Centro de Previsão de Tempo e Estudos Climáticos (CPTEC) do Instituto Nacional de Pesquisas Espaciais (INPE) apresentam-se como um... (Resumo completo, clicar acesso eletrônico abaixo) / Abstract: Global Navigation Satellite Systems (GNSS) technology has been widely used in positioning, from day-to-day applications (metric accuracy) to applications that require high accuracy (few cm or dm). For high accuracy, different techniques may be applied to minimize the effects that the signal suffers from its transmission on the satellite to its reception. GNSS signal when propagating in the neutral atmosphere (from surface up to 50km) is influenced by hydrostatic gases and water vapor. The variation of these atmospheric constituents causes a refraction in the signal that generates a delay. This delay may cause errors of at least 2.5 m (zenith) and greater than 25 m (slant). The determination of the delay in the slanted direction (satellite-receiver) according to the elevation angle is performed by the mapping functions. One of the techniques for calculating the delay is raytracing. This technique allows us to map the actual path that the signal has traveled and to model the interference of the neutral atmosphere on it. Different approaches can be used to obtain information describing the neutral atmosphere constituents - temperature, pressure and humidity. The possibilities include the use of radiosonde measurements, weather and climate models (NWP), GNSS measurements, as well as theoretical models. Regional NWP models from the Center Weather Forecasting and Climate Studies (CPTEC) of the National Institute for Space Research (INPE) are a good alternative to provide atmospheri... (Complete abstract click electronic access below) / Doutor