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Thesis (M.S.)--Air Force Institute of Technology, 2007. / AFIT/GIR/ENV/07-M15. Title from title page of PDF document (viewed on: Nov. 28, 2007). "March 2007." Includes bibliographical references (leaves 170-174).

Thesis (M.S. in Operations Research)--Naval Postgraduate School, 1980. / "March 1980." Thesis advisor: W. P. Hughes. Includes bibliographical references P. 85. Also available online.

The main objective of the VPI-CE control network. is to contribute to the Nation.al Geodetic Survey control network. In order to meet this objective, large amounts of survey data were accumulated at different times from various surveys between the years 1977-1980. Bach different set of survey data was reduced and adjusted by least squares independently creating various "sub" control networks that were connected to each other peace- . meal. When "sub" control networks were connected to each other, it was found that they did not meet the objective stated above. It is the purpose of this project to examine and check all survey data, adjust all data as one set to the NGS control network, and to evaluate the adjusted data to see if the survey meets second-order class II traverse specifications as established by the NGS. Included in this paper are the following: a background on NGS specifications; least squares theory including observation equations, and error theory; a description of how data for the project was accumulated and reduced; the adjustment of the reduced survey data; results and analysis of the adjustment; and conclusions and recommendations for the survey. / Master of Engineering

Indoor localization systems have a variety of applications such as tracking of assets, indoor robot navigation, and monitoring of people (e.g. patients) in hospitals or at home. Global positioning system (GPS) offers location accuracy of several meters and is mainly used for outdoor location-based applications as its accuracy degrades significantly in indoor scenarios. Wireless local area networks (WLAN) have also been used for indoor localization, but the accuracy is too low and power consumption of WLAN terminals is too high for most applications. Ultra-wideband (UWB) localization is superior in terms of accuracy and power consumption compared with GPS and WLAN localization, and is thus more suitable for most indoor location-based applications [1-4]. The accuracy and precision requirements of localization systems depend on the specific characteristics of the applications. For example, centimeter or even millimeter localization accuracy is required for dynamic part tracking, while decimeter accuracy might be sufficient for tracking patients in hospitals or at home. Note that accuracy is not the only aspect of the overall performance of the system. Factors such as cost, range, and complexity should also be considered in system design. In the first part of this dissertation, a centimeter-accurate UWB localization system is developed. The technical challenges to achieve centimeter localization accuracy are investigated. Since all the receivers are synchronized through wire connection in this system, a wireless localization system with centimeter accuracy is introduced in order to make the system easier for deployment. A two-step synchronization algorithm with picosecond accuracy is presented, and the system is tested in a laboratory environment. The second part of this dissertation focuses on reducing the complexity of UWB localization systems when the localization accuracy requirement is relaxed. An UWB three-dimensional localization scheme with a single cluster of receivers is proposed. This scheme employs the time-of-arrival (TOA) technique and requires no wireless synchronization among the receivers. A hardware and software prototype that works in the 3.1-5.1 GHz range is constructed and tested in a laboratory environment. An average position estimation error of less than 3 decimeter is achieved by the experimental system. This TOA scheme with receivers in a single unit requires synchronization between the transmitter and the receiver unit. In order to further reduce system complexity, a new time-difference-of-arrival localization scheme is proposed. This scheme requires multiple units, each operating on its own clock. It avoids synchronization between the transmitter and receivers, and thus makes the development of the transmitter extremely simple. The performance of this system is simulated and analyzed analytically, and turns out to be satisfactory for most indoor localization applications. / Graduation date: 2013

This thesis investigates automatic geolocation (i.e. identification of the location, expressed as latitude/longitude coordinates) of documents. Geolocation can be an effective means of summarizing large document collections and is an important component of geographic information retrieval. We describe several simple supervised methods for document geolocation using only the document’s raw text as evidence. All of our methods predict locations in the context of geodesic grids of varying degrees of resolution. We evaluate the methods on geotagged Wikipedia articles and Twitter feeds. For Wikipedia, our best method obtains a median prediction error of just 11.8 kilometers. Twitter geolocation is more challenging: we obtain a median error of 479 km, an improvement on previous results for the dataset. / text

The purpose of this monograph is to study the mathematical principles behind the Global Positioning System, the so-called GPS. We start with a historical approach of the evolution of this technology. Then we show some theorems in geometry: plane, spatial and analytic, which together with some physical principles (average speed, speed of light, the Doppler effect,...) guided the creators of this powerful tool that determines with remarkable accuracy the position (latitude, longitude and altitude) of a transmitter. Finally, we suggest activities to be performed at the level of basic education, to stimulate students curiosity by scientific knowledge contained therein. / A presente monografia tem como objetivo evidenciar os princípios matemáticos por trás do funcionamento do Sistema de Posicionamento Global conhecido por GPS. Após uma abordagem geral da evolução ocorrida até chegarmos a essa tecnologia, demonstraremos alguns teoremas das geometrias: plana, espacial e analítica que, aplicados juntamente com alguns princípios da Física (velocidade média, velocidade da luz, efeito Doppler,...), nortearam os criadores desta poderosa ferramenta que determina com notáveis precisão e exatidão, em qualquer parte do globo terrestre incluindo a atmosfera, a hora e a posição (latitude, longitude e altitude) de um transmissor. E, a partir daí, sugerir atividades interdisciplinares, a serem desenvolvidas em nível de educação básica, que estimulem a curiosidade dos alunos pelos conhecimentos científicos nelas contidos.