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.

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

2021 ◽  
pp. 632-652
Author(s):  
Guermah Bassma ◽  
Sadiki Tayeb ◽  
El Ghazi Hassan
Keyword(s):  
Em Algorithm ◽  
Statistical Tests ◽  
Hybrid Approach ◽  
Gaussian Mixture ◽  
High Accuracy ◽  
Global Navigation Satellite Systems ◽  
Positioning System ◽  
Satellite Systems ◽  
Global Positioning ◽  
Global Navigation Satellite

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.

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.

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.

scholarly journals TRANSLATING AERIAL IMAGES INTO STREET-MAP-LIKE REPRESENTATIONS FOR VISUAL SELF-LOCALIZATION OF UAVS

2019 ◽  
Vol XLII-2/W13 ◽  
pp. 575-580 ◽  
Author(s):  
M. Schleiss
Keyword(s):  
Global Positioning System ◽  
Global Navigation Satellite Systems ◽  
Aerial Imagery ◽  
Aerial Images ◽  
Visual Localization ◽  
Localization Accuracy ◽  
Satellite Systems ◽  
Global Positioning ◽  
Reference Map ◽  
Global Navigation Satellite

<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>

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.

scholarly journals Using signals from GLONASS/GPS navigation systems to correct the readings of a digital magnetic compass

2019 ◽  
Vol 30 ◽  
pp. 03006
Author(s):  
Hau Vu Xuan ◽  
V.E. Ivanov ◽  
Thach Nguyen Dinh
Keyword(s):  
Global Positioning System ◽  
Magnetic Compass ◽  
Global Navigation Satellite Systems ◽  
Positioning System ◽  
Navigation Systems ◽  
Satellite Systems ◽  
Gps Navigation ◽  
Global Positioning ◽  
Global Navigation Satellite ◽  
Compass System

The article describes the results obtained from research, manufacture and quality improvement of an inexpensive digital magnetic compass system. Given that the receivers of the global navigation satellite systems (GNSS) signals are not expensive, in order to increase the accuracy and reliability of the compass, in this paper, the authors propose a method to use the signal of the GNSS global positioning system to compare and adjust the azimuth value of the Digital magnetic compass (DMC).

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.

Interference and Spoofing

2014 ◽  
pp. 54-83
Author(s):  
Fabio Dovis ◽  
Luciano Musumeci ◽  
Nicola Linty ◽  
Marco Pini
Keyword(s):  
Global Navigation Satellite Systems ◽  
Added Value ◽  
Positioning System ◽  
Navigation Satellite ◽  
Satellite Systems ◽  
Wide Range ◽  
Global Positioning ◽  
Military Applications ◽  
Processing Algorithms ◽  
Global Navigation Satellite

This chapter deals with one of the major concerns for reliable use of Global Navigation Satellite Systems (GNSS), providing a description of intentional and unintentional threats, such as interference, jamming, and spoofing. Despite the fact that these phenomena have been studied since the early stages of Global Positioning System (GPS), they were mainly addressed for military applications of GNSS. However, a wide range of recent civil applications related to user safety or featuring financial implications would be deeply affected by interfering or spoofing signals intentionally created. For such a reason, added value processing algorithms are being studied and designed in order to embed in the receiver an interference reporting capability so that they can monitor and possibly mitigate interference events.

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