Critical Issues in Global Navigation Satellite Systems

2011 ◽  
pp. 151-157
Author(s):  
Ina Freeman ◽  
Jonathan M. Auld
Keyword(s):  
Atomic Clock ◽  
Global Navigation Satellite Systems ◽  
Time Interval ◽  
Navigation Satellite ◽  
Satellite Systems ◽  
Critical Issues ◽  
Radio Signals ◽  
Global Navigation ◽  
Defense Research ◽  
Global Navigation Satellite

Global Navigation Satellite Systems (GNSS) is a concept that relays accurate information of a position or location anywhere on the globe using a minimum of four satellites, a control station, and a user receiver. GNSS owes its origins to Rabi’s work in the early 1940s with the concept of an atomic clock (Nobel Museum, http://www.nobel.se/physics/laureates/1944/rabi-bio.html). In October 1940, the National Defense Research Council in the U.S. recommended implementing a new navigation system that combined radio signals with this new technology of time interval measurements. From this, MIT developed Long Range Radio Aid to Navigation (LORAN), which was refined by scientists at John Hopkins University and utilized during World War II through the late 1950s.

Global Navigation Satellite Systems

2011 ◽  
pp. 348-352 ◽  
Author(s):  
Phillip Olla
Keyword(s):  
Global Navigation Satellite Systems ◽  
Global Network ◽  
Navigation Satellite ◽  
Satellite Systems ◽  
Mobile Phone Technology ◽  
Sensing Applications ◽  
Radio Signals ◽  
High Resolution Images ◽  
Global Navigation ◽  
Global Navigation Satellite

There is a need to determine precise ground locations for use in a variety of innovative and emerging applications such as earth observation, mobile-phone technology, and rescue applications. Location information is pertinent to a large number of remote sensing applications, some of which support strategic tasks such as disaster management, earth monitoring, protecting the environment, management of natural resources, and food production. With the availability of high-resolution images, some applications will require a location precision down to 1 m (Kline, 2004). The global navigation satellite systems (GNSSs) provide signals that can serve this purpose; these signals can be incorporated into a large range of innovative applications with immense benefits for the users (Hollansworth, 1999). Satellite navigation is achieved by using a global network of satellites that transmit radio signals from approximately 11,000 miles in high earth orbit. The technology is accurate enough to pinpoint locations anywhere in the world, 24 hours a day. Positions are provided in latitude, longitude, and altitude. This article provides an overview of the GNSSs in operation along with their uses.

scholarly journals Modelagem fuzzy aplicada na detecção da vulnerabildade à erosão costeira

2013 ◽  
Vol 19 (4) ◽  
pp. 746-764 ◽  
Author(s):  
Luciana Maria da Silva ◽  
Rodrigo Mikosz Gonçalves ◽  
Milde Maria da Silva Lira ◽  
Pedro de Souza Pereira
Keyword(s):  
Global Navigation Satellite Systems ◽  
Navigation Satellite ◽  
Satellite Systems ◽  
Global Navigation ◽  
Global Navigation Satellite

O crescimento da urbanização vem provocando grandes transformações nas relações sociais e morfológica das áreas costeiras. O presente trabalho tem como objetivo modelar massa de dados de diversas fontes como GNSS (Global Navigation Satellite Systems) e sensoriamento remoto para posteriormente prover a espacialização da vulnerabilidade costeira à erosão utilizando a lógica fuzzy. O método aplicado para análise da vulnerabilidade utilizou variáveis linguísticas, partições fuzzy, intervalos e análises paramétricas que caracterizam a modelagem fuzzy. Após análise, os níveis de vulnerabilidade à erosão costeira ao longo da linha de costa nas cidades do Recife e Jaboatão dos Guararapes no litoral de Pernambuco apresentaram os seguintes resultados: 33,33% da linha de costa possuem vulnerabilidade baixa, 38,15% possui vulnerabilidade moderada, 14,26% vulnerabilidade alta e 14,26% muito alta.

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