scholarly journals Estimating ocean tide loading displacements with GPS and GLONASS

Solid Earth ◽  
2020 ◽  
Vol 11 (5) ◽  
pp. 1849-1863
Author(s):  
Bogdan Matviichuk ◽  
Matt King ◽  
Christopher Watson
Keyword(s):  
Global Positioning System ◽  
Western Europe ◽  
Satellite System ◽  
Ocean Tide ◽  
Ground Displacement ◽  
Ocean Tide Loading ◽  
Global Positioning ◽  
Tidal Constituents ◽  
The Uk ◽  
Global Navigation Satellite

Abstract. Ground displacements due to ocean tide loading have previously been successfully observed using Global Positioning System (GPS) data, and such estimates for the principal lunar M2 constituent have been used to infer the rheology and structure of the asthenosphere. The GPS orbital repeat period is close to that of several other major tidal constituents (K1, K2, S2); thus, GPS estimates of ground displacement at these frequencies are subject to GPS systematic errors. We assess the addition of GLONASS (GLObal NAvigation Satellite System) to increase the accuracy and reliability of eight major ocean tide loading constituents: four semi-diurnal (M2, S2, N2, K2) and four diurnal constituents (K1, O1, P1, Q1). We revisit a previous GPS study, focusing on 21 sites in the UK and western Europe, expanding it with an assessment of GLONASS and GPS+GLONASS estimates. In the region, both GPS and GLONASS data have been abundant since 2010.0. We therefore focus on the period 2010.0–2014.0, a span considered long enough to reliably estimate the major constituents. Data were processed with a kinematic precise point positioning (PPP) strategy to produce site coordinate time series for each of three different modes: GPS, GLONASS and GPS+GLONASS. The GPS solution with ambiguities resolved was used as a baseline for performance assessment of the additional modes. GPS+GLONASS shows very close agreement with ambiguity resolved GPS for lunar constituents (M2, N2, O1, Q1) but with substantial differences for solar-related constituents (S2, K2, K1, P1), with solutions including GLONASS being generally closer to model estimates. While no single constellation mode performs best for all constituents and components, we propose to use a combination of constellation modes to recover tidal parameters: GPS+GLONASS for most constituents, except for K2 and K1 where GLONASS (north and up) and GPS with ambiguities resolved (east) perform best.

scholarly journals Estimating ocean tide loading displacements with GPS and GLONASS

2020 ◽  
Author(s):  
Bogdan Matviichuk ◽  
Matt King ◽  
Christopher Watson
Keyword(s):  
Western Europe ◽  
Close Agreement ◽  
Systematic Errors ◽  
Ocean Tide ◽  
Gps Data ◽  
Ground Displacement ◽  
Ocean Tide Loading ◽  
Tidal Constituents ◽  
Kinematic Ppp ◽  
The Uk

Abstract. Ground displacements due to ocean tide loading have previously been successfully observed using GPS data, and such estimates for the principal lunar M2 constituent have been used to infer the rheology and structure of the asthenosphere. The GPS orbital repeat period is close to several other major tidal constituents (K1, K2, S2) thus GPS-estimates of ground displacement at these frequencies is subject to GPS systematic errors. We assess the addition of GLONASS to increase the accuracy and reliability over eight major ocean tide loading constituents: four semi-diurnal (M2, S2, N2, K2) and four diurnal constituents (K1, O1, P1, Q1). We revisit a previous GPS study, focusing on 21 sites in the UK and Western Europe, expanding it with an assessment of GLONASS and GPS+GLONASS estimates. In the region, both GPS and GLONASS data are abundant since 2010.0. We therefore focus on the period 2010.0–2014.0 which is considered long enough to reliably estimate the major constituents. Data were processed with a kinematic PPP strategy to produce site coordinate time series for each of 3 different modes: GPS, GLONASS and GPS+GLONASS. The GPS solution with ambiguities resolved was used as a baseline for performance assessment of the additional modes. GPS+GLONASS shows very close agreement with ambiguity resolved GPS for lunar constituents (M2, N2, O1, Q1) but substantial differences for solar-related constituents (S2, K2, K1, P1). While no single constellation mode performs best for all constituents and components, we propose to use a combination of constellation modes to recover tidal parameters: GPS+GLONASS for most constituents except for K2 and K1 where GLONASS (north and up) and GPS with ambiguities resolved (east), perform best.

scholarly journals Performance Assessment of PPP Surveys with Open Source Software Using the GNSS GPS–GLONASS–Galileo Constellations

2020 ◽  
Vol 10 (16) ◽  
pp. 5420 ◽  
Author(s):  
Antonio Angrisano ◽  
Gino Dardanelli ◽  
Anna Innac ◽  
Alessandro Pisciotta ◽  
Claudia Pipitone ◽  
...  
Keyword(s):  
Open Source ◽  
Global Positioning System ◽  
Open Source Software ◽  
Satellite System ◽  
Satellite Orbits ◽  
International Gnss Service ◽  
Static Mode ◽  
Global Positioning ◽  
Significant Performance ◽  
Global Navigation Satellite

In this work, the performance of the multi-GNSS (Global Navigation Satellite System) Precise Point Positioning (PPP) technique, in static mode, is analyzed. Specifically, GPS (Global Positioning System), GLONASS, and Galileo systems are considered, and quantifying the Galileo contribution is one of the main objectives. The open source software RTKLib is adopted to process the data, with precise satellite orbits and clocks from CNES (Centre National d’Etudes Spatiales) and CLS (Collecte Localisation Satellites) analysis centers for International GNSS Service (IGS). The Iono-free model is used to correct ionospheric errors, the GOT-4.7 model is used to correct tidal effects, and Differential Code Biases (DCB) are taken from the Deutsche Forschungsanstalt für Luftund Raumfahrt (DLR) center. Two different tropospheric models are tested: Saastamoinen and Estimate ZTD (Zenith Troposhperic Delay). For the proposed study, a dataset of 31 days from a permanent GNSS station, placed in Palermo (Italy), and a dataset of 10 days from a static geodetic receiver, placed nearby the station, have been collected and processed by the most used open source software in the geomatic community. The considered GNSS configurations are seven: GPS only, GLONASS only, Galileo only, GPS+GLONASS, GPS+Galileo, GLONASS+Galileo, and GPS+GLONASS+Galileo. The results show significant performance improvement of the GNSS combinations with respect to single GNSS cases.

scholarly journals Covariance Analysis of Real-Time Precise GPS Orbit Estimated from Double-Differenced Carrier Phase Observations

2019 ◽  
Vol 11 (19) ◽  
pp. 2271 ◽  
Author(s):  
Sunkyoung Yu ◽  
Donguk Kim ◽  
Junesol Song ◽  
Changdon Kee
Keyword(s):  
Fault Detection ◽  
Real Time ◽  
Global Positioning System ◽  
Carrier Phase ◽  
Satellite System ◽  
Additional Parameter ◽  
Global Positioning ◽  
Correlation Information ◽  
Global Navigation Satellite ◽  
Orbit Errors

The covariance of real-time global positioning system (GPS) orbits has been drawing attention in various fields such as user integrity, navigation performance improvement, and fault detection. The international global navigation satellite system (GNSS) service (IGS) provides real-time orbit standard deviations without correlations between the axes. However, without correlation information, the provided covariance cannot assure the performance of the orbit product, which would, in turn, causes significant problems in fault detection and user integrity. Therefore, we studied real-time GPS orbit covariance characteristics along various coordinates to effectively provide conservative covariance. To this end, the covariance and precise orbits are estimated by means of an extended Kalman filter using double-differenced carrier phase observations of 61 IGS reference stations. Furthermore, we propose a new method for providing covariance to minimize loss of correlation. The method adopted by the IGS, which neglects correlation, requires 4.5 times the size of the covariance to bind orbit errors. By comparison, our proposed method reduces this size from 4.5 to 1.3 using only one additional parameter. In conclusion, the proposed method effectively provides covariance to users.

Urban Fleet Monitoring with GPS and GLONASS

1998 ◽  
Vol 51 (3) ◽  
pp. 382-393 ◽  
Author(s):  
M. Tsakiri ◽  
M. Stewart ◽  
T. Forward ◽  
D. Sandison ◽  
J. Walker
Keyword(s):  
Global Positioning System ◽  
Public Transport ◽  
Urban Areas ◽  
Dead Reckoning ◽  
Satellite System ◽  
Basic Function ◽  
Positioning System ◽  
Positioning Systems ◽  
Global Positioning ◽  
Global Navigation Satellite

The increasing volume of traffic in urban areas has resulted in steady growth of the mean driving time on fixed routes. Longer driving times lead to significantly higher transportation costs, particularly for vehicle fleets, where efficiency in the distribution of their transport tasks is important in staying competitive in the market. For bus fleets, the optimal control and command of the vehicles is, as well as the economic requirements, a basic function of their general mission. The Global Positioning System (GPS) allows reliable and accurate positioning of public transport vehicles except within the physical limitations imposed by built-up city ‘urban canyons’. With a view to the next generation of satellite positioning systems for public transport fleet management, this paper highlights the limitations imposed on current GPS systems operating in the urban canyon. The capabilities of a future positioning system operating in this type of environment are discussed. It is suggested that such a system could comprise receivers capable of integrating the Global Positioning System (GPS) and the Russian equivalent, the Global Navigation Satellite System (GLONASS), and relatively cheap dead-reckoning sensors.

Accounting for Inter-System Bias in DGNSS Positioning with GPS/GLONASS/BDS/Galileo

2017 ◽  
Vol 70 (4) ◽  
pp. 686-698 ◽  
Author(s):  
Hui Liu ◽  
Bao Shu ◽  
Longwei Xu ◽  
Chuang Qian ◽  
Rufei Zhang ◽  
...  
Keyword(s):  
Global Positioning System ◽  
Simple Algorithm ◽  
Satellite System ◽  
Harsh Environments ◽  
Positioning System ◽  
Gnss Positioning ◽  
Global Positioning ◽  
System Bias ◽  
Global Navigation Satellite ◽  
Reliability And Availability

Code Differential Global Positioning System (DGPS) is widely used in satellite navigation and positioning because of its simple algorithm and preferable precision. Multi-Global Navigation Satellite System (GNSS) is expected to enhance the accuracy, reliability and availability of Differential GNSS (DGNSS) positioning. Traditional DGNSS models should set separate clock parameters due to the clock differences between the different systems. Awareness of the Inter-System Bias (ISB) could help to maximise the redundancy of the positioning model, thus improving the performance of multi-GNSS positioning. This paper aims to examine the inter-system bias of GPS/GLONASS/BeiDou (BDS)/Galileo and their benefits in DGNSS positioning. Results show that Differential ISB (DISB) characteristics vary with different receiver types and systems. The size of DISB could reach metre-level and the precision of estimated DISBs can reach approximately several centimetres within tens of epochs. Therefore, a new real-time DGNSS model that accounts for ISB is proposed. After differential ISBs are initialised, positioning with four satellites from arbitrarily the same or different systems can be realised. Moreover, compared with the traditional DGNSS model, the precision of the positioning results with the new model are obviously improved, especially in harsh environments.

scholarly journals Comparison of L1 and L5 Bands GNSS Signals Acquisition

Sensors ◽  
2018 ◽  
Vol 18 (9) ◽  
pp. 2779 ◽  
Author(s):  
Jérôme Leclère ◽  
René Landry Jr. ◽  
Cyril Botteron
Keyword(s):  
Global Positioning System ◽  
Satellite System ◽  
Positioning System ◽  
Global Positioning ◽  
Accurate Comparison ◽  
The Common ◽  
Parallel Code ◽  
L5 Signal ◽  
Global Navigation Satellite ◽  
Pilot Channel

Nowadays, civil Global Navigation Satellite System (GNSS) signals are available in both L1 and L5 bands. A receiver does not need to acquire independently the signals in both bands coming from a same satellite, since their carrier Doppler and code delay are closely related. Therefore, the question of which one to acquire first rises naturally. Although the common thought would tell the L1 band signals which are narrowband, an accurate comparison has never been done, and the decision is not as easy as it seems. Indeed, L5 band signals have several advantages such as stronger power, lower carrier Doppler, or a pilot channel, unlike the Global Positioning System (GPS) L1 C/A signal. The goal of this paper is therefore to compare the acquisition of L1 and L5 bands signals (GPS L1 C/A and L5, Galileo E1 and E5a/b) to determine which one is more complex and by which factor, in terms of processing time and memory, considering hardware receivers and the parallel code search. The results show that overall the L5 band signals are more complex to acquire, but it depends strongly on the conditions. The E5 signal is always more complex to acquire than E1, while the L5 signal can have a complexity close to the L1 C/A in some cases. Moreover, precise assistance providing accurate Doppler could significantly reduce the L5 complexity below the L1 complexity.

scholarly journals SBAS/EGNOS for Maritime

2020 ◽  
Vol 8 (10) ◽  
pp. 764
Author(s):  
Manuel Lopez-Martinez ◽  
José-Manuel Álvarez ◽  
José-Maria Lorenzo ◽  
Carlos Garcia Daroca
Keyword(s):  
Global Positioning System ◽  
Service Provision ◽  
Satellite System ◽  
User Communities ◽  
Global Positioning ◽  
Primary Means ◽  
Augmentation Techniques ◽  
Maritime Navigation ◽  
Gnss Receivers ◽  
Global Navigation Satellite

The Global Navigation Satellite System (GNSS) has become the primary means of obtaining Position, Navigation, and Timing (PNT) information at sea. The current capabilities of the Global Positioning System (GPS) constellation, although adequate for ocean navigation, have some shortfalls for coastal navigation: some user communities have a need for enhanced performance and they can benefit from the available “augmentation” techniques, resulting in improved GPS performance. Nowadays, the users can take advantage of Satellite-Based Augmentation Systems (SBASs). The maritime domain has been used SBAS for several years and it is supported by GNSS receivers used in the recreational and professional sectors. The SBAS/European Geostationary Navigation Overlay Service (EGNOS) can be used to complement the differential GNSS (DGNSS) for the provision of enhanced accuracy and integrity information with additional benefits. There are different possible solutions for the transmission of SBAS/EGNOS information to maritime users, considering that the corrections can be available from different transmission means. The different options for the use of SBAS for maritime navigation, the benefits brought to mariners, as well as the associated regulations, standardization and service provision aspects, are presented in this article.

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.

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