scholarly journals The Galileo Ground Segment Integrity Algorithms: Design and Performance

2008 ◽  
Vol 2008 ◽  
pp. 1-16 ◽  
Author(s):  
Carlos Hernández Medel ◽  
Carlos Catalán Catalán ◽  
Miguel Angel Fernández Vidou ◽  
Esther Sardón Pérez
Keyword(s):  
Algorithm Design ◽  
Satellite System ◽  
Navigation Satellite ◽  
Safety Requirements ◽  
Ground Segment ◽  
Global Positioning ◽  
Processing Facility ◽  
And Performance ◽  
Global Navigation Satellite ◽  
Software Prototype

Galileo, the European Global Navigation Satellite System, will provide to its users highly accurate global positioning services and their associated integrity information. The element in charge of the computation of integrity messages within the Galileo Ground Mission Segment is the integrity processing facility (IPF), which is developed by GMV Aerospace and Defence. The main objective of this paper is twofold: to present the integrity algorithms implemented in the IPF and to show the achieved performance with the IPF software prototype, including aspects such as: implementation of the Galileo overbounding concept, impact of safety requirements on the algorithm design including the threat models for the so-called feared events, and finally the achieved performance with real GPS and simulated Galileo scenarios.

scholarly journals A New Multipath Mitigation Method for GNSS Receivers Based on an Antenna Array

2012 ◽  
Vol 2012 ◽  
pp. 1-11 ◽  
Author(s):  
Sébastien Rougerie ◽  
Guillaume Carrié ◽  
François Vincent ◽  
Lionel Ries ◽  
Michel Monnerat
Keyword(s):  
Satellite System ◽  
Navigation Satellite ◽  
Tracking Loop ◽  
Multipath Mitigation ◽  
Expectation Maximisation ◽  
Gnss Receivers ◽  
Reduced Complexity ◽  
And Performance ◽  
Global Navigation Satellite ◽  
Cramer Rao Bound

The well-known Space-Alternating Generalized Expectation Maximisation (SAGE) algorithm has been recently considered for multipath mitigation in Global Navigation Satellite System (GNSS) receivers. However, the implementation of SAGE in a GNSS receiver is a challenging issue due to the numerous number or parameters to be estimated and the important size of the data to be processed. A new implementation of the SAGE algorithm is proposed in this paper in order to reach the same efficiency with a reduced complexity. This paper focuses on the trade-off between complexity and performance thanks to the Cramer Rao bound derivation. Moreover, this paper shows how the proposed algorithm can be integrated with a classical GNSS tracking loop. This solution is thus a very promising approach for multipath mitigation.

scholarly journals Design and Performance Analysis of BDS-3 Integrity Concept

2021 ◽  
Vol 13 (15) ◽  
pp. 2860
Author(s):  
Cheng Liu ◽  
Yueling Cao ◽  
Gong Zhang ◽  
Weiguang Gao ◽  
Ying Chen ◽  
...  
Keyword(s):  
Satellite System ◽  
Navigation Satellite ◽  
Concept Design ◽  
Tree Model ◽  
System A ◽  
Design Values ◽  
Actual Operation ◽  
Integrity Risk ◽  
And Performance ◽  
Global Navigation Satellite

Compared to the BeiDou regional navigation satellite system (BDS-2), the BeiDou global navigation satellite system (BDS-3) carried out a brand new integrity concept design and construction work, which defines and achieves the integrity functions for major civil open services (OS) signals such as B1C, B2a, and B1I. The integrity definition and calculation method of BDS-3 are introduced. The fault tree model for satellite signal-in-space (SIS) is used, to decompose and obtain the integrity risk bottom events. In response to the weakness in the space and ground segments of the system, a variety of integrity monitoring measures have been taken. On this basis, the design values for the new B1C/B2a signal and the original B1I signal are proposed, which are 0.9 × 10−5 and 0.8 × 10−5, respectively. The hybrid alarming mechanism of BDS-3, which has both the ground alarming approach and the satellite alarming approach, is explained. At last, an integrity risk analysis and verification work were carried out using the operating data of the system in 2019. The results show that the actual operation of the system is consistent with the conceptual design, which satisfies the integrity performance promised by BDS-3 in the ICAO SAPRs.

scholarly journals Mapeamento participativo aplicado à Estratégia de Saúde da Família: a experiência em Santo Amaro - BA

2021 ◽  
Vol 73 (2) ◽  
pp. 646-665
Author(s):  
Isabel Cristina Moraes ◽  
Shanti Nitya Marengo ◽  
Gustavo Luís Schacht ◽  
Débora Santos Passos
Keyword(s):  
Global Positioning System ◽  
Global Navigation Satellite System ◽  
Satellite System ◽  
Google Earth ◽  
Positioning System ◽  
Navigation Satellite ◽  
Global Positioning ◽  
Global Navigation ◽  
Global Navigation Satellite

O acesso a geolocalização em smartphones e tablets tem apontado seu uso potencial no levantamento de dados georreferenciados e como ferramenta de mapeamento replicável por usuários não-especialistas. O objetivo deste artigo é apresentar a experiência do mapeamento participativo dos territórios de ação das equipes de Estratégia de Saúde da Família (ESF) do município de Santo Amaro (BA) com recursos de GPS/GNSS (Global Positioning System/Global Navigation Satellite System) e imagem de satélite do Google Earth, no aplicativo Map Marker. Neste trabalho, são apresentados os aspectos da percepção e transcrição dos elementos espaciais no processo de digitalização e atualização cartográfica destes territórios.  Foram realizadas oficinas nas 17 unidades básicas de saúde (UBS) a fim de cartografar os territórios de atuação – microáreas - dos 104 Agentes Comunitários de Saúde (ACS). Das 17 UBS, 10 apresentavam algum produto cartográfico. Esses produtos pré-existentes contribuíram para a correspondência espacial entre o território e as imagens de satélite. A identificação das microáreas foi satisfatória, porém, o maior desafio foi a vetorização das poligonais. Apesar disso, em cada equipe houve ao menos um profissional que se destacou e foi capaz de reproduzir a metodologia sem um mediador. O uso das tecnologias geoespaciais aplicadas ao mapeamento em saúde mostrou-se viável para a área de estudo, e reforça a importância do treinamento para a autonomia dos atores sociais e a democratização desses recursos nas estratégias em saúde pública. A obtenção destas bases cartográficas deve subsidiar à espacialização de doenças registradas na atenção básica bem como à gestão de saúde do município.

scholarly journals A bagging tree-based pseudorange correction algorithm for global navigation satellite system positioning in foliage canyons

2021 ◽  
Vol 17 (5) ◽  
pp. 155014772110167
Author(s):  
Fan Qin ◽  
Linxia Fu ◽  
Yuanqing Wang ◽  
Yi Mao
Keyword(s):  
Global Positioning System ◽  
Global Navigation Satellite System ◽  
Satellite System ◽  
Navigation Satellite ◽  
Positioning Accuracy ◽  
Improvement Rate ◽  
System Solution ◽  
Global Positioning ◽  
Global Navigation ◽  
Global Navigation Satellite

Global navigation satellite system is indispensable to provide positioning, navigation, and timing information for pedestrians and vehicles in location-based services. However, tree canopies, although considered as valuable city infrastructures in urban areas, adversely degrade the accuracy of global navigation satellite system positioning as they attenuate the satellite signals. This article proposes a bagging tree-based global navigation satellite system pseudorange error prediction algorithm, by considering two variables, including carrier to noise C/ N0 and elevation angle θe to improve the global navigation satellite system positioning accuracy in the foliage area. The positioning accuracy improvement is then obtained by applying the predicted pseudorange error corrections. The experimental results shows that as the stationary character of the geostationary orbit satellites, the improvement of the prediction accuracy of the BeiDou navigation satellite system solution (85.42% in light foliage and 83.99% in heavy foliage) is much higher than that of the global positioning system solution (70.77% in light foliage and 73.61% in heavy foliage). The positioning error values in east, north, and up coordinates are improved by the proposed algorithm, especially a significant decrease in up direction. Moreover, the improvement rate of the three-dimensional root mean square error of positioning accuracy in light foliage area test is 86% for BeiDou navigation satellite system/global positioning system combination solutions, while the corresponding improvement rate is 82% for the heavy foliage area test.

Monitoring the Integrity of GNSS

1994 ◽  
Vol 47 (2) ◽  
pp. 181-190
Author(s):  
N. Ward
Keyword(s):  
Global Positioning System ◽  
The United States ◽  
Satellite System ◽  
Positioning System ◽  
Navigation Satellite ◽  
Fishing Vessels ◽  
Global Positioning ◽  
Replacement System ◽  
Global Navigation Satellite ◽  
Technical Considerations

The purpose of the study on which this paper is based was to establish whether there was a maritime requirement for a Global Navigation Satellite System (GNSS) integrity monitoring and warning service in UK and Irish waters, and, if so, how best it could be established and operated.The scope of the study extended to all maritime users: merchant ships; fishing vessels; pleasure craft; and all aspects of the voyage: harbour/harbour approach; coastal and ocean passage.It has been assumed that the United States Global Positioning System (GPS) would be the system adopted, since it is the closest to an operational state. However, most of the technical considerations would apply equally to the Russian GLONASS or any future replacement system under international control.The views expressed are those of the author, and should not be taken to represent the policies of the Department of Transport or any of the other bodies mentioned.

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