Influência de diferentes condições da ionosfera no posicionamento por ponto com GPS: avaliação na região brasileira

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Estimativas do IWV utilizando receptores GPS em bases terrestres no Brasil: sinergia entre a geodésia e a meteorologia

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Uso do receptor GPS topográfico na obtenção de cartas e modelo digital do terreno

Pós-graduação em Agronomia (Energia na Agricultura) - FCA

Avaliação do posicionamento plano-altimétrico com receptor gps em diferentes tipos de uso do solo

Pós-graduação em Agronomia (Energia na Agricultura) - FCA

Implantação da rede geodésica UNESP para integração ao sistema geodésico brasileiro

Pós-graduação em Agronomia (Irrigação e Drenagem) - FCA

Reading strategies - from L1 to L2.

This paper intends to present a selection of the most useful reading strategies for the typical ESP students in Brazilian universities, showing whether the readers use them in their native language or not, the way the teacher should develop these strategies in the classroom, the problems involved in their use and the reasons for using them.

Análise de modelos troposféricos no posicionamento baseado em redes usando o conceito de VRS

In the past few years several GPS (Global Position System) positioning techniques have been develope and/or improved with the goal of obtaining high accuracy and productivity in real time. The reference station network concept besides to enabling quality and reliability in positioning for scientific and civil GPS community, allows studies concerning tropospheric refraction modeling in the network region. Moreover, among the network corrections transmission methods available to users, there is the VRS (Virtual Reference Station) concept. In this method, the data of a virtual station are generated near the rover receiver (user). This provides a short baseline and the user has the possibility of using a single frequency receiver to accomplish the relative positioning. In this paper, the methodology applied to generate VRS data, using different tropospheric models is described. Thus, comparative tests were conducted in the four seasons with the NWP/INPE (Numerical Weather Prediction/National Institute for Space Research) and Hopfield tropospheric models. In order to analyse the VRS data quality, it was used the Precise Point Positioning (PPP) method, where satisfactory results were found. Mean differences between PNT/INPE and Hopfield models of 9.75% and 24.2% for the hydrostatic and wet days, respectively were obtained.

First results from an airborne GPS radio occultation system for atmospheric profiling

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

análise dos efeitos ionosféricos de ordem superior no ciclo solar 24 e influência no posicionamento GNSS absoluto

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Análise multiescala de séries temporais do efeito da cintilação ionosférica nos sinais de satélite GPS a partir de wavelets não decimadas

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Inverse Modeling of GPS Multipath for Snow Depth Estimation-Part I: Formulation and Simulations

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Inverse Modeling of GPS Multipath for Snow Depth Estimation-Part II: Application and Validation

GPS multipath reflectometry (GPS-MR) is a technique that uses geodetic quality GPS receivers to estimate snow depth. The accuracy and precision of GPS-MR retrievals are evaluated at three different sites: grasslands, alpine, and forested. The assessment yields a correlation of 0.98 and an rms error of 6-8 cm for observed snow depths of up to 2.5 m. GPS-MR underestimates in situ snow depth by 10%-15% at these three sites, although the validation methods do not measure the same footprint as GPS-MR.

Web Service para geração de VRS no contexto de posicionamento GPS

Internet is fully inserted in contemporary society, specially in relation to entertainment services and trading. Its reach has transposed the traditional desktop computer models coming to mobile devices like cell phones and GPS receivers. Likewise, the scientific community takes its benefits, both for publication of studies and for communication between clusters processing information, such as at LHC, located in Switzerland. Concerning geodetic positioning, researches in the area present the concept of Virtual Reference Stations - VRS, in which is necessary a communication way between the real reference stations and a central system as well as between central system and a service requester. In this work, we analyze the current solutions for generation of VRS with regard to data delivery for the service requester and present a solution based on Web Services as an alternative to the model being developed by Spatial Geodesy Study Group – GEGE/FCT/UNESP. Comparing solutions, it was verified the potential of Web Services to aid in researches of geodetic positioning using VRS. Using such technology, it is obtained interoperability, providing greater flexibility to develop client applications, both development carried out by researchers of the university or by any person or enterprise wishing to use the service

Tarefas de triangulação com restrições perceptuais em pessoas com deficiência auditiva: um estudo por meio de gps

This study aimed to investigate how people with hearing disability perform tasks of distances estimation for locomotion and navigation when deprived of effective perceptual and proprioceptive information. For this, participants with hearing disability went three distances being the first and second 100 meters and the third 140 meters (triangulation) from a source point in an inverted L open field trajectory and then returned to the origin, and the first two were driven by a researcher guide with adapted GPS coordinates of the study, and the third being three free-form sessions, the first one without any perceptual and proprioceptive restriction, the second without visual perception, and the third on the wheel-chair, that is, without proprioception. The results showed that people with hearing disability without the knowledge of the path do not possess satisfactory accuracy but when they learn the way even with the restriction of visual perception and proprioception they can return to the starting point in a task of triangulation. The "t" students test with a significance level of 5% (2.131) indicates significant differences between the first task without any perceptual restriction and the third where they performed in the wheelchair. To achieve these results we used remote monitoring via GPS and the TrackMaker software.