How to make a multi-billion dollar thermometer

2021 ◽  
Vol 57 (2) ◽  
pp. 025003
Author(s):  
William H Baird
Keyword(s):  
Positional Information ◽  
The United States ◽  
Global Navigation Satellite Systems ◽  
Physics Students ◽  
Satellite Systems ◽  
Global Positioning ◽  
Field Programmable ◽  
Radio Signals ◽  
Global Navigation Satellite ◽  
Precise Time

Abstract The United States’ Global Positioning System (GPS), and similar geolocation systems such as Galileo, GLONASS, and Beidou are used by people all over the globe. Modern receivers of these global navigation satellite systems can track multiple satellites from different constellations. Casual, non-technical users are probably aware that the positional information provided is typically accurate to within a few meters. We could expect physics students to infer that, because these systems rely on the travel time of radio signals, this implies time measurement accuracy on the scale of tens of nanoseconds. This feature has led to GPS-enabled Internet time servers providing stratum 1 accuracy for under $1000. In this paper, we will show that we can couple a GPS unit to a field programmable gate array (FPGA) to determine the temperature in a room. The more serious application of this GPS-FPGA pairing is to provide precise time-stamping of events, thereby synchronizing data collection between stations across a room or across the globe.

Vulnerability Assessment of the U.S. Transportation Infrastructure that Relies on the Global Positioning System

2003 ◽  
Vol 56 (2) ◽  
pp. 185-193 ◽  
Author(s):  
James V. Carroll
Keyword(s):  
Global Positioning System ◽  
The United States ◽  
Global Navigation Satellite Systems ◽  
Positioning System ◽  
Satellite Systems ◽  
The Public ◽  
Transportation Modes ◽  
Global Positioning ◽  
Global Navigation Satellite ◽  
The U.S

During the course of its development for military use and more recent extension to many civilian uses, vulnerabilities of Global Navigation Satellite Systems (GNSS) – in the United States the Global Positioning System (GPS) – have become apparent. The vulnerabilities arise from natural, intentional, and unintentional sources. Increasing civilian and military reliance on GNSS brings with it a vital need to identify the critical vulnerabilities to civilian users, and to develop a plan to mitigate these vulnerabilities. This paper summarizes the findings of the U.S. Department of Transportation (DOT) vulnerability study that addresses these issues. The key findings are that satellite navigation users are vulnerable to several classes of disruption that affect all transportation modes and related infrastructure; but also that the vulnerabilities can be mitigated by awareness, planning, and using independent backup systems and/or alternate procedures in safety-critical applications. To gain the full benefits of GNSS, it will be necessary to analyse safety-of-life vulnerabilities in detail, and to determine the means and costs of reducing these risks to acceptable levels. The complete assessment report, of which this paper is a synopsis, was released to the public on September 10, 2001. Although the basic findings apply to all GNSS, the assessment focused on the GPS, in response to the enabling Presidential Decision Directive.

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.

Past, present, and future of the technological tracking methods to assess tactical variables in team sports: A systematic review

2020 ◽  
Vol 234 (4) ◽  
pp. 281-290 ◽  
Author(s):  
Markel Rico-González ◽  
José Pino-Ortega ◽  
Fabio Y Nakamura ◽  
Felipe Arruda Moura ◽  
Daniel Rojas-Valverde ◽  
...  
Keyword(s):  
Global Positioning System ◽  
Systematic Reviews ◽  
Team Sports ◽  
Global Navigation Satellite Systems ◽  
Positioning System ◽  
Navigation Satellite ◽  
Satellite Systems ◽  
Global Positioning ◽  
Global Navigation ◽  
Global Navigation Satellite

The main aim of this work was to review the use of technological tracking methods to assess collective spatial-positioning variables in team sports. Following the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines and PICO design for systematic reviews, study identification was performed in four databases (PubMed, SPORTDiscus, ProQuest Central, and Web of Science). Articles were selected if they focused on player position and technological tracking methods. After duplicate removal, 2194 articles were identified based on the established search criteria, of which 72 articles were selected and analysed. Semi-automatic optic-based systems, Global Positioning System/Global Navigation Satellite Systems, and local positioning systems were used in 60%, 33% and 7% of the studies, respectively. All studies that measured tactical variables by local positioning system technology in team sports used local position measurement technology. Optic-based systems were used more often in the early years to analyse collective tactical behaviour during competition. Later, Global Positioning System/Global Navigation Satellite Systems became more frequent to measure behaviour in team sports during the training process. The possibility of using the same system during competition and training will facilitate the assessment of collective tactical behaviour in team sports.

scholarly journals Galileo: a consolidação do sistema de posicionamento europeu

2020 ◽  
Vol 8 (4) ◽  
pp. 238
Author(s):  
Crislaine Menezes da Silva ◽  
Paulo De Tarso Setti Júnior ◽  
Daniele Barroca Marra Alves ◽  
João Francisco Galera Monico
Keyword(s):  
Global Positioning System ◽  
Global Navigation Satellite Systems ◽  
Positioning System ◽  
Navigation Satellite ◽  
Satellite Systems ◽  
Global Positioning ◽  
Global Navigation ◽  
Global Navigation Satellite

O Galileo é a contribuição da União Europeia ao GNSS (ingl. Global Navigation Satellite Systems – Sistemas de Navegação Global por Satélite) e está próximo da declaração da fase operacional completa, que deve ocorrer no final de 2020 ou início de 2021. Este sistema começou a ser concebido na década de 90, após a decisão do governo americano em não permitir que outras nações participassem da construção e manutenção do sistema NAVSTAR – GPS (ingl. Global Positioning System – Sistema de Posicionamento Global). O sistema Galileo é a primeira contribuição civil para o GNSS e foi desenvolvido de forma a ser independente dos outros sistemas nos segmentos espacial, de controle e operacional. Além disso, está sendo desenvolvido para ser interoperável e compatível com os outros GNSS, em especial o GPS. Nos últimos anos, o desenvolvimento do Galileo fez progressos significativos. A constelação atual compreende um total de 26 satélites orbitando a Terra, 22 operacionais, dos quais três pertencentes à primeira geração de satélites de validação de órbita, e a infraestrutura de controle terrestre está em pleno funcionamento.  Para o usuário, são transmitidos sinais em três frequências E1, E5 e E6. Os sinais em E1 e E5 são transmitidos nas mesmas frequências que os sinais GPS L1 e L5 e ambos sistemas usam princípios de modulação equivalentes. Isso é benéfico pois proporciona uma melhor cobertura e maior robustez para usuários que podem utilizar os sistemas de forma combinada. Além disso, o Galileo oferece vários novos serviços específicos, como o serviço aberto, o serviço de alta acurácia e de busca e resgate. Como o sistema Galileo está atualmente em fase final de implantação, faz-se necessário na literatura brasileira, um artigo que trate exclusivamente desse sistema, este artigo apresenta o estado da arte do sistema Galileo (julho de 2020). Resultados iniciais demonstraram que o Galileo tem acurácia comparável ao GPS, no posicionamento por ponto simples.

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.

scholarly journals Dst Index as a Potential Indicator of Approaching GNSS Performance Deterioration

2012 ◽  
Vol 66 (1) ◽  
pp. 149-160 ◽  
Author(s):  
Renato Filjar ◽  
Serdjo Kos ◽  
Siniša Krajnovic
Keyword(s):  
Global Positioning System ◽  
Mediterranean Area ◽  
Global Navigation Satellite Systems ◽  
Ionospheric Storm ◽  
Satellite Systems ◽  
Dst Index ◽  
Global Positioning ◽  
Potential Indicator ◽  
Performance Deterioration ◽  
Global Navigation Satellite

Space weather disturbances cause considerable effects on Global Navigation Satellite Systems (GNSS) performance and operation, affecting society and the economy due to the growing reliance on GNSS, especially in densely populated mid-latitudes. Recent studies hypothesised potential utilisation of the Disturbance storm-time (Dst) index for indication of an approaching ionospheric storm and possible deterioration of the GNSS positioning performance. We challenged the hypothesis in the case of the Halloween 2003 event in an attempt to confirm the direct correlation between the Dst index dynamics and the Global Positioning System (GPS) positioning performance in the mid-latitude Mediterranean area. Our results provide no evidence of the direct Dst-GNSS performance correlation for the observed event.

GNSS Positioning Enhancement Based on NLOS Multipath Biases Estimation Using Gaussian Mixture Noise

2018 ◽  
Vol 9 (1) ◽  
pp. 21-39 ◽  
Author(s):  
Guermah Bassma ◽  
Sadiki Tayeb ◽  
El Ghazi Hassan
Keyword(s):  
Em Algorithm ◽  
Global Positioning System ◽  
Statistical Tests ◽  
Hybrid Approach ◽  
Gaussian Mixture ◽  
Global Navigation Satellite Systems ◽  
Satellite Systems ◽  
Global Positioning ◽  
Global Navigation Satellite ◽  
Non Line Of Sight

Global navigation satellite systems (GNSS) have been widely used in many applications where positioning plays an important role. However, the performances of these applications can be degraded in urban canyons, due to Non-Line-Of-Sight (NLOS) and Multipath interference affecting GNSS signals. In order to ensure high accuracy positioning, this article proposes to model the NLOS and Multipath biases by Gaussian Mixture noise using Expectation Maximization (EM) algorithm. In this context, an approach to estimate the Multipath and NLOS biases for real time positioning is presented and statistical tests for searching the probability distribution of NLOS and Multipath biases are illustrated. Furthermore, a hybrid approach based on PF (Particle Filter) and EM algorithm for estimating user position in hard environment is presented. Using real GPS (Global Positioning System) signal, the efficiency of the proposed approach is shown, and a significant improvement of the positioning accuracy over the simple PF estimation is obtained.

scholarly journals The contribution of engineering surveys by means of GPS to the determination of crustal movements in Istanbul

2011 ◽  
Vol 11 (6) ◽  
pp. 1705-1713 ◽  
Author(s):  
M. Özyaşar ◽  
M. T. Özlüdemir
Keyword(s):  
Positional Information ◽  
Global Navigation Satellite Systems ◽  
Marmara Region ◽  
Satellite Systems ◽  
Geodetic Networks ◽  
The North ◽  
Richter Scale ◽  
Tectonically Active ◽  
Vertical Displacements ◽  
Global Navigation Satellite

Abstract. Global Navigation Satellite Systems (GNSS) are space based positioning techniques and widely used in geodetic applications. Geodetic networking accomplished by engineering surveys constitutes one of these tasks. Geodetic networks are used as the base of all kinds of geodetic implementations, Co from the cadastral plans to the relevant surveying processes during the realization of engineering applications. Geodetic networks consist of control points positioned in a defined reference frame. In fact, such positional information could be useful for other studies as well. One of such fields is geodynamic studies that use the changes of positions of control stations within a network in a certain time period to understand the characteristics of tectonic movements. In Turkey, which is located in tectonically active zones and struck by major earthquakes quite frequently, the positional information obtained in engineering surveys could be very useful for earthquake related studies. For this purpose, a GPS (Global Positioning System) network of 650 stations distributed over Istanbul (Istanbul GPS Triangulation Network; abbreviated IGNA) covering the northern part of the North Anatolian Fault Zone (NAFZ) was established in 1997 and measured in 1999. From 1998 to 2004, the IGNA network was extended to 1888 stations covering an area of about 6000 km2, the whole administration area of Istanbul. All 1888 stations within the IGNA network were remeasured in 2005. In these two campaigns there existed 452 common points, and between these two campaigns two major earthquakes took place, on 17 August and 12 November 1999 with a Richter scale magnitude of 7.4 and 7.2, respectively. Several studies conducted for estimating the horizontal and vertical displacements as a result of these earthquakes on NAFZ are discussed in this paper. In geodynamic projects carried out before the earthquakes in 1999, an annual average velocity of 2–2.5 cm for the stations along the NAFZ were estimated. Studies carried out using GPS observations in the same area after these earthquakes indicated that point displacements vary depending on their distance to the epicentres of the earthquakes. But the directions of point displacements are similar. The results obtained through the analysis of the IGNA network also show that there is a common trend in the directions of point displacements in the study area. In this paper, the past studies about the tectonics of Marmara region are summarised and the results of the displacement analysis on the IGNA network are discussed.

scholarly journals Performance of GPS Positioning in the Presence of Irregularities in the Auroral and Polar Ionospheres during EISCAT UHF/ESR Measurements

2021 ◽  
Vol 13 (23) ◽  
pp. 4798
Author(s):  
Habila Mormi John ◽  
Biagio Forte ◽  
Ivan Astin ◽  
Tom Allbrook ◽  
Alex Arnold ◽  
...  
Keyword(s):  
Global Navigation Satellite Systems ◽  
Positioning Error ◽  
Satellite Systems ◽  
Gps Positioning ◽  
Transient Nature ◽  
Radio Signals ◽  
E Region ◽  
Global Navigation Satellite ◽  
The Impact ◽  
Residual Errors

Irregularities in the spatial distribution of ionospheric electron density introduce temporal fluctuations in the intensity and phase of radio signals received from Global Navigation Satellite Systems (GNSS). The impact of phase fluctuations originating from irregularities in the auroral and polar ionospheres on GPS positioning was investigated on three days in March 2018 in the presence of quiet-to-moderately disturbed magnetic conditions by combining measurements from GPS and EISCAT UHF/ESR incoherent scatter radars. Two different positioning solutions were analysed: broadcast kinematic (BK) and precise static (PS). The results show that the propagation through irregularities induced residual errors on the observables leading to an increase in the positioning error, in its variability, and in the occurrence of gaps. An important aspect emerging from this study is that the variability of the 3-D positioning error was reduced, and the presence of gaps disappeared when the positioning solutions were evaluated at a 1 s rate rather than at a 30 s rate. This is due to the transient nature of residual errors that are more significant over 30 s time intervals in the presence of irregularities with scale size between few kilometres in the E region to few tens of kilometres in the F region.

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