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 O Efeito das Covariâncias entre os Componentes de Linha Base sobre a Confiabilidade de Redes GNSS: Resultados para uma Rede com Alta Redundância

2021 ◽  
Vol 73 (2) ◽  
pp. 666-684
Author(s):  
Maria Luísa Silva Bonimani ◽  
Vinicius Francisco Rofatto ◽  
Marcelo Tomio Matsuoka ◽  
Ivandro Klein ◽  
Mauricio Roberto Veronez ◽  
...  
Keyword(s):  
Global Navigation Satellite System ◽  
Satellite System ◽  
Navigation Satellite ◽  
System A ◽  
Global Navigation ◽  
Global Navigation Satellite

A mais recente versão da teoria da confiabilidade tem sido utilizada para descrever a capacidade de um sistema de medição em detectar, identificar e remover outliers a um certo nível de probabilidade. Entretanto, as aplicações desta teoria têm sido direcionadas para redes simuladas de nivelamento. Aqui, por outro lado, aplicamos a teoria no contexto de redes baseadas nos sistemas de posicionamento por satélites GNSS (Global Navigation Satellite System), a partir de dados reais coletados em campo. Testamos se as covariâncias entre as componentes da linha base têm efeito sobre a confiabilidade. Verificamos que as covariâncias entre as componentes da linha base aumentam a taxa de sucesso na identificação de outlier e, portanto, aumentam a confiabilidade da rede. O menor outlier identificável – ao nível de 80% de correta identificação – teve uma redução média de ~30% para as componentes ΔX e ΔY, e ~14% para ΔZ em comparação ao cenário com covariâncias nulas. O aumento do nível de significância melhora a confiabilidade em ambos os cenários (covariâncias nulas e não-nulas) na mesma proporção. Porém, para altos níveis de significância (α > 0,1) e sistemas com boa redundância (ri > 0,5), a confiabilidade para um modelo estocástico com covariâncias nulas se aproxima do caso em que as covariâncias não são nulas. Na ausência de um modelo estocástico mais realista (covariâncias não-nulas) e para sistemas com boa redundância local (ri > 0,5), deve-optar por regiões críticas maiores ( k < 2,8).

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 Spoofing and Anti-Spoofing Technologies of Global Navigation Satellite System: A Survey

IEEE Access ◽  
2020 ◽  
Vol 8 ◽  
pp. 165444-165496
Author(s):  
Zhijun Wu ◽  
Yun Zhang ◽  
Yiming Yang ◽  
Cheng Liang ◽  
Rusen Liu
Keyword(s):  
Global Navigation Satellite System ◽  
Satellite System ◽  
Navigation Satellite ◽  
System A ◽  
Global Navigation ◽  
Global Navigation Satellite

scholarly journals Assimilation of GNSS PWV with NCAR-RTFDDA to Improve Prediction of a Landfall Typhoon

2022 ◽  
Vol 14 (1) ◽  
pp. 178
Author(s):  
Haishen Wang ◽  
Yubao Liu ◽  
Yuewei Liu ◽  
Yunchang Cao ◽  
Hong Liang ◽  
...  
Keyword(s):  
Water Vapor ◽  
Data Assimilation ◽  
Precipitable Water ◽  
Satellite System ◽  
Navigation Satellite ◽  
System A ◽  
Spiral Rainbands ◽  
Global Navigation Satellite ◽  
Four Dimensional Data Assimilation ◽  
The Impact

Precipitable water vapor (PWV) retrieved from ground-based global navigation satellite system (GNSS) stations acquisition signal of a navigation satellite system provides high spatial and temporal resolution atmospheric water vapor. In this paper, an observation-nudging-based real-time four-dimensional data assimilation (RTFDDA) approach was used to assimilate the PWV estimated from GNSS observation into the WRF (Weather Research and Forecasting) modeling system. A landfall typhoon, “Mangkhut”, is chosen to evaluate the impact of GNSS PWV data assimilation on its track, intensity, and precipitation prediction. The results show that RTFDDA can assimilate GNSS PWV data into WRF to improve the water vapor distribution associated with the typhoon. Assimilating the GNSS PWV improved the typhoon track and intensity prediction when and after the typhoon made landfall, correcting a 5–10 hPa overestimation (too deep) of the central pressure of the typhoon at landfall. It also improved the occurrence and the intensity of the major typhoon spiral rainbands.

Integrity monitoring for Kalman filter-based localization

2020 ◽  
Vol 39 (13) ◽  
pp. 1503-1524
Author(s):  
Guillermo Duenas Arana ◽  
Osama Abdul Hafez ◽  
Mathieu Joerger ◽  
Matthew Spenko
Keyword(s):  
Kalman Filter ◽  
Time Window ◽  
Satellite System ◽  
Navigation Satellite ◽  
Robot Localization ◽  
Sensor Faults ◽  
Prior Work ◽  
Integrity Monitoring ◽  
Integrity Risk ◽  
Global Navigation Satellite

The problem of quantifying robot localization safety in the presence of undetected sensor faults is critical when preparing for future applications where robots may interact with humans in life-critical situations; however, the topic is only sparsely addressed in the robotics literature. In response, this work leverages prior work in aviation integrity monitoring to tackle the more challenging case of evaluating localization safety in Global Navigation Satellite System (GNSS)-denied environments. Localization integrity risk is the probability that a robot’s pose estimate lies outside pre-defined acceptable limits while no alarm is triggered. In this article, the integrity risk (i.e., localization safety) is rigorously upper bounded by accounting for both nominal sensor noise and other non-nominal sensor faults. An extended Kalman filter is employed to estimate the robot state, and a sequence of innovations is used for fault detection. The novelty of the work includes (1) the use of a time window to limit the number of monitored fault hypotheses while still guaranteeing safety with respect to previously occurring faults and (2) a new method to account for faults in the data association process.

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 Influência do multicaminhamento de sinais dos satélites GNSS e do tempo de rastreio na precisão do PPP para vértices de limites da NTGIR

2018 ◽  
Vol 10 (1) ◽  
Author(s):  
George Nascimento Carvalho ◽  
Luiz Guimarães Barbosa ◽  
Rosane Maciel de Araújo Vargas ◽  
Tiago Lima Rodrigues
Keyword(s):  
Global Navigation Satellite System ◽  
Satellite System ◽  
Navigation Satellite ◽  
System A ◽  
Global Navigation ◽  
Global Navigation Satellite

Com o avanço das tecnologias na área de posicionamento terrestre, aumentam as expectativas em contribuir para a regularização fundiária no país. Esta atividade é importante para o desenvolvimento da nação. Manter atualizada a documentação e determinar precisamente a quem pertence o imóvel é um desafio. Nos últimos anos, as técnicas de levantamento têm evoluído significativamente com relação aos métodos de Posicionamento GNSS (Global Navigation Satellite System). A partir da segunda edição da Norma Técnica para Georreferenciamento de Imóveis Rurais do INCRA (NTGIR), o Posicionamento por Ponto Preciso (PPP) passou a ser aceito como método de processamento de dados GNSS. Neste trabalho foram avaliados os efeitos do multicaminhamento e do tempo de rastreio para a determinação de pontos de limites da NTGIR utilizando o método PPP. Os resultados foram avaliados com base nos indicadores MP1 e MP2 e nos gráficos de PDOP e foram, em sua maioria, adequados à precisão dessa norma. Foi observado que a maior influência do efeito do multicaminhamento ocorre na portadora L2. Ressalta-se que, apesar deste fato, é importante utilizar receptores de dupla frequência para a coleta dos dados para o PPP para que os efeitos de primeira ordem da ionosfera sejam modelados. Recomendam-se para trabalhos futuros mais avaliações do efeito do multicaminhamento em ambientes onde os sinais dos satélites não alcançam diretamente o receptor e que apresentam superfícies refletoras ou bloqueadoras dos sinais e a construção de mapas de obstruções e testes estatísticos para que seja analisada também a acurácia dos pontos.

Sign in / Sign up

Export Citation Format

Share Document