scholarly journals Hyperbolic Asynchronous Method of a Radio Navigation Technique

2020 ◽  
Vol 10 (18) ◽  
pp. 6316
Author(s):  
Ryszard J. Katulski ◽  
Jarosław Sadowski ◽  
Jacek Stefański ◽  
Wojciech Siwicki

Humans have always wanted to determine positions in an unknown environment. At the beginning, methods were simple. They were based on the observation of characteristic points—in the case of shipping, additional observations of the coastline. Then came navigation based on astronomical methods (astronavigation). At the beginning of the XX-th century, a new way of determining the current location was developed. It used radio wave signals. First came radio beacons, then ground-based systems. Currently, satellite systems are being used. At present, the most popular one is the Global Positioning System (GPS). This system is fully controlled by the Department of Defense, and only the U.S. forces and their closest allies have been guaranteed the accuracy offered by the system. Armies of other countries can only use the civilian version. This situation has engendered the need for an independent radiolocation system. This article describes the construction and operation of such a technology demonstrator that was developed at Gdansk University of Technology. The main advantage of the system is the ability to manage it without the chain organization of the reference stations, which currently work with each other asynchronously. This article demonstrates the functionality of such a system. It also presents results and analysis of its effectiveness.

Author(s):  
Markel Rico-González ◽  
José Pino-Ortega ◽  
Fabio Y Nakamura ◽  
Felipe Arruda Moura ◽  
Daniel Rojas-Valverde ◽  
...  

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.


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

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.


1982 ◽  
Vol 36 (1) ◽  
pp. 5-8
Author(s):  
J. David Boal

Although the U.S. Department of Defense is developing the NAVSTAR/Global Positioning System (GPS) for its military positioning and navigation requirements, there are obvious civilian benefits to be gained from exploiting this global satellite system. No present navigation system offers the continuous worldwide accuracy in time and position which GPS will deliver. Even now, with only four prototype satellites in operation, GPS users have demonstrated that the accuracy of the system has exceeded design goals. Future applications will include geodynamics, the unification of geodetic datums, surveying, mapping, navigation, hydrography, offshore resource exploration and development, and marine and air traffic management.


2012 ◽  
Vol 66 (1) ◽  
pp. 149-160 ◽  
Author(s):  
Renato Filjar ◽  
Serdjo Kos ◽  
Siniša Krajnovic

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.


Author(s):  
Guermah Bassma ◽  
Sadiki Tayeb ◽  
El Ghazi Hassan

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.


2017 ◽  
Vol 22 (4) ◽  
pp. 51-58
Author(s):  
Damian Faustryjak ◽  
Michał Majchrowicz ◽  
Lidia Jackowska-Strumiłło

Abstract The paper presents a web application for navigation through the university campus, which is based on Global Positioning System GPS and OpenStreetMap. The application has a multilayer structure and multi-labelling support. The proposed solution ensures better management of visual data and more efficient image processing comparing to the other known methods. With the new search system, users can place a lot of information on one layer without losing the legibility of displayed data. All the information that was displayed on the map was grouped and assigned to the appropriate categories.Therefore a map contains a lot of related information that needs to be linked to each other. The system has been divided into modules that ensure the integrity of the displayed things. Presenting so much information at the same time is managed by modules. Their main job is to provide results that is then segregated and grouped. The system presented in this paper was applied for Lodz University of Technology.


Author(s):  
M. Schleiss

<p><strong>Abstract.</strong> Unmanned aerial vehicles (UAVs) rely on global navigation satellite systems (GNSS) like the Global Positioning System (GPS) for navigation but GNSS signals can be easily jammed. Therefore, we propose a visual localization method that uses a camera and data from Open Street Maps in order to replace GNSS. First, the aerial imagery from the onboard camera is translated into a map-like representation. Then we match it with a reference map to infer the vehicle’s position. An experiment over a typical sized mission area shows localization accuracy close to commercial GPS. Compared to previous methods ours is applicable to a broader range of scenarios. It can incorporate multiple types of landmarks like roads and buildings and it outputs absolute positions with higher frequency and confidence and can be used at altitudes typical for commercial UAVs. Our results show that the proposed method can serve as a backup to GNSS systems where suitable landmarks are available.</p>


2003 ◽  
Vol 56 (2) ◽  
pp. 185-193 ◽  
Author(s):  
James V. Carroll

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.


2015 ◽  
Vol 2015 ◽  
pp. 1-6
Author(s):  
Amirhossein Fereidountabar ◽  
Gian Carlo Cardarilli ◽  
Marco Re

Mathematical analysis and optimization of a carrier tracking loop are presented. Due to fast changing of the carrier frequency in some satellite systems, such as Low Earth Orbit (LEO) or Global Positioning System (GPS), or some planes like Unmanned Aerial Vehicles (UAVs), high dynamic tracking loops play a very important role. In this paper an optimized tracking loop consisting of a third-order Phase Locked Loop (PLL) assisted by a second-order Frequency Locked Loop (FLL) for UAVs is proposed and discussed. Based on this structure an optimal loop has been designed. The main advantages of this approach are the reduction of the computation complexity and smaller phase error. The paper shows the simulation results, comparing them with a previous work.


Author(s):  
N. Vijayalakshmi ◽  
K. Kiruthika

This main aim of this project to provide voice-based navigation system for blind people using voice recognition module and it is intended to provide overall measures object detection and real time assistance via Global Positioning System (GPS) and ultrasonic sensors. This project aims at the development of an Electronic Travelling Aid (ETA) kit to help the blind people to find obstacle free path. This ETA is fixed to the stick of the blind people. When the object is detected near to the blinds stick it alerts them with the help of vibratory circuit. The blind person will give the destination’s name as the input to voice recognition module. GPS module continuously receives the latitude and longitude of the current location. GPS compares it with the destination’s latitude and longitude. The blind person receives the pronounced directions which he needs to follow to reach his destination.


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