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SVN49 and others GPS anomalies: elevation-dependent pseudorange errors in block 2-RS and 2R-MS / Tim A. Springer in Inside GNSS, vol 4 n° 4 (July - August 2009)
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Titre : SVN49 and others GPS anomalies: elevation-dependent pseudorange errors in block 2-RS and 2R-MS Type de document : Article/Communication Auteurs : Tim A. Springer, Auteur ; F. Dilssner, Auteur Année de publication : 2009 Article en page(s) : 5 p. ; pp 32 - 36 Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Géodésie spatiale
[Termes IGN] erreur de mesure
[Termes IGN] mesurage de pseudo-distance
[Termes IGN] positionnement par GPSRésumé : (Auteur) This is an updated version of the web article, Saving SVN49, that includes discussion of the elevation-dependent pseudoranging anomaly on the most recently launched GPS satellite and similar anomalies observed on other GPS satellites. An investigation into the elevation-dependent pseudoranging anomaly on the most recently launched GPS satellite reveals that the U.S. Air Force has implemented an intentional alteration in the broadcast ephemerides and clock data in order to correct the anomaly. The investigators conclude that the solution will probably work for normal navigation users but may pose a difficulty for some high-precision users. Copyright Gibbons Media & Research LLC Numéro de notice : A2009-664 Affiliation des auteurs : non IGN Thématique : POSITIONNEMENT Nature : Article DOI : sans Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=33565
in Inside GNSS > vol 4 n° 4 (July - August 2009) . - 5 p. ; pp 32 - 36[article]Exemplaires(1)
Code-barres Cote Support Localisation Section Disponibilité 159-09041 SL Revue Centre de documentation Revues en salle Disponible Documents numériques
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Titre : High-resolution GPS tomography in view of hydrological hazard assessment Type de document : Thèse/HDR Auteurs : Simon Lutz, Auteur Editeur : Zurich : Schweizerischen Geodatischen Kommission / Commission Géodésique Suisse Année de publication : 2009 Collection : Geodätisch-Geophysikalische Arbeiten in der Schweiz, ISSN 0257-1722 num. 76 Importance : 200 p. Format : 21 x 30 cm ISBN/ISSN/EAN : 978-3-908440-20-8 Note générale : Bibliographie
Doctoral thesisLangues : Anglais (eng) Descripteur : [Vedettes matières IGN] Applications de géodésie spatiale
[Termes IGN] aérosol
[Termes IGN] atmosphère terrestre
[Termes IGN] Bernese
[Termes IGN] campagne d'expérimentation
[Termes IGN] collocation
[Termes IGN] distribution spatiale
[Termes IGN] double différence
[Termes IGN] interpolation spatiale
[Termes IGN] météorologie
[Termes IGN] méthode des moindres carrés
[Termes IGN] modèle atmosphérique
[Termes IGN] prévision météorologique
[Termes IGN] propagation troposphérique
[Termes IGN] réfraction atmosphérique
[Termes IGN] risque naturel
[Termes IGN] temps réel
[Termes IGN] teneur en vapeur d'eau
[Termes IGN] tomographie
[Termes IGN] traitement de données GNSS
[Termes IGN] Valais (Suisse)
[Termes IGN] vapeur d'eau
[Termes IGN] voxelIndex. décimale : 30.83 Applications océanographiques de géodésie spatiale Résumé : (Auteur) In the last few years, the use of propagation delays of GNSS radio signals due to the atmospheric effect has gained considerable importance as a valuable contribution to numerical weather forecasting. GPS-based tomography is a dedicated method to resolve the temporal variation and spatial distribution of the most important constituent of the atmosphere, the tropospheric water vapor. The four-dimensional tomographic approach, however, has not yet been completely established. Investigations on the small-scale high-resolution configuration will now help to determine and model water vapor distribution and variation over local, mountainous catchment areas. Especially, the development towards near real-time analysis with a high update rate of less than one hour will reveal the potential in the field of short and medium range forecasts.
Three main objectives were defined for this research project: The first objective was the study of the feasibility of GPS tomography in a small-scale and Alpine area. Furthermore, the processing of campaign-type measurements had to be considered specifically. The second aim was the determination of the four-dimensional distribution of atmospheric water vapor over a local region using GPS tomography in view of hydrological hazard assessment. Thirdly, aspects of real-time determination had to be investigated. In this context, it had to be accounted for that, instead of precise GNSS satellite orbits, predicted ones like broadcast ephemerides or ultra-rapid orbits had to be used. Also, it had to be addressed that the processing time is a critical issue in real-time computation. As a consequence, the parameters of the complete GPS processing were refined and adapted to near real-time applications. Furthermore, new algorithms in the tomographic software were to be designed and evaluated.
The tomographic software package AWATOS (Atmospheric Water Vapor Tomography Software), developed at the Geodesy and Geodynamics Laboratory, ETH Zurich, was used for the assimilation of double-differenced GPS observations and interpolated meteorological data sets. The spatial distribution of water vapor can be determined by least-squares inversion with a high temporal resolution.
The work was carried out in five steps: Simulations helped to design an optimal GPS network for the tomographic purpose. Based on these findings, two dedicated field campaigns were performed to study the feasibility of the method for a non-permanent densification network in an Alpine region in Switzerland. Secondly, GPS derived zenith total delays (ZTD) as well as double-differenced residuals were estimated using a high performance and high accuracy post-processing software package (Bernese GPS Software Version 5.0). The results were validated by comparison with independent methods. With the software package COMEDIE, meteorological data was collocated and interpolated for the separation of the total delays into a wet and a dry part. In the third step, this set of data was processed with the GPS tomography software package AWATOS to obtain spatially and temporally highly-resolved wet refractivity fields. An automatic generation of tomographic voxel models was developed in the forth step. This tool allows high flexibility in tomographic processing and forms a fundamental part of an adaptive method of choosing voxel models at a particular spatial resolution. In the fifth step, the aspects of near real-time processing were investigated.
Measurements from a solar spectrometer and data from the current numerical weather model COSMO-7 of MeteoSwiss were available for comparison purposes. During the campaigns, radiosondes were launched to measure vertical profiles of the tropospheric meteorological components in situ and to validate the tomographic results.
The success of the tomographic method was revealed by the statistical analyses. The wet refractivity profiles from the GPS tomography software package AWATOS in the high-resolution mode match the profiles derived from corresponding radiosonde measurements within 10 ppm (refractivity units). The AWATOS profiles represent the characteristics of the different tropospheric layers in most cases with high significance.
The accuracy of GPS tomography in near real-time was assessed based on dedicated case studies with real-time orbits. The error budget of the near real-time calculations was compared to the best postprocessing solutions available. Due to large variations in the time series of the Up component of the GPS coordinate estimation, the broadcast ephemerides are not recommended for GPS meteorological applications. But ultra-rapid orbits, which are also available in real-time, yield satisfying results regarding tropospheric parameter estimation (ZTD) and the high-resolution GPS tomographic analysis.Note de contenu : 1 Introduction
1.1 Trends in GPS meteorology
1.2 Research review of atmospheric water vapor profiling
1.3 Significance of high-resolution GPS tomography
1.3.1 For the research community
1.3.2 For practical applications
1.4 Objectives
1.5 Structure
2 Theoretical background of GPS meteorology
2.1 Atmospheric water vapor
2.2 Radio wave refractivity
2.3 Refraction and path delay modeling
2.3.1 Definition
2.3.2 The Saastamoinen formula
2.3.3 Integrating tropospheric refractivity
2.3.4 Path delay interpolation with COITROPA
2.4 The Global Positioning System (GPS)
2.4.1 Introduction to GPS
2.4.2 The GPS observation equations
2.4.3 Mapping functions and standard models
2.4.4 Troposphere modeling in the Bernese GPS Software
2.5 The software package COMEDIE
2.5.1 4-D refractivity field from meteorological data
2.5.2 Estimation of tropospheric path delays
3 Ground-based GPS tomography of the neutral atmosphere
3.1 Models, methods and algorithms
3.1.1 The tomographic voxel model
3.1.2 The apriori model .
3.1.3 Inter-voxel constraints
3.1.4 Separation of the total path delay
3.2 The software package AWATOS
3.2.1 Double-difference GPS tomography
3.2.2 The tomographic equation system
3.2.3 Ray tracing and the design matrix
3.2.4 (Pscudo-) Observations and the weight matrix
3.2.5 Error budget
3.3 Network analysis tool
4 Outline of the two field campaigns
4.1 Introduction
4.2 The project area in the canton of Valais (Switzerland)
4.3 The July 2005 field campaign
4.3.1 GPS network
4.3.2 Meteorological ground measurement network
4.3.3 Radiosondes
4.4 The October 2005 field campaign
4.4.1 GPS Network
4.4.2 Meteorological ground measurement network
4.4.3 Radiosondes
4.4.4 Solar Spectrometry for comparison purpose
5 Data preprocessing
5.1 Introduction
5.2 GPS data processing
5.2.1 Overview
5.2.2 Criteria for fix station selection
5.2.3 Parameter settings in the Bernese GPS Software
5.2.4 Network solutions
5.2.5 Section summary
5.3 Meteorological data processing
5.4 Path delay comparison
6 The numerical weather model COSMO-7
6.1 Model description
6.2 Distribution of the available data
6.3 Data processing workflow
6.4 Data analysis
6.4.1 Comparison with balloon sounding profiles
6.4.2 Time series of integrated path delays
6.4.3 Comparison with time series of hourly GPS-ZTD
6.4.4 ZTD comparison with rainfall data
7 Enhancements of AWATOS
7.1 Introduction
7.2 New models and algorithms
7.2.1 Designing the voxel model
7.2.2 Obtaining a priori information
7.2.3 Allocation of meteorological data
7.2.4 Selection of beneficial stations
7.3 Further analysis tools
7.4 Notes on near real-tirnc analysis and predictive algorithms
7.5 Accuracy and reliability assessment
8 Results and discussion
8.1 Towards high spatial resolution
8.1.1 Impact of vertical spacing
8.1.2 Vertical resolution and cutoff elevation angle
8.1.3 Impact of horizontal spacing
8.1.4 Summary on the July 2005 campaign data
8.1.5 Summary on the October 2005 campaign data
8.1.6 Impact of a reduced network in October 2005
8.1.7 Discussion on spatial resolution
8.2 Correlation analysis with meteorological surface data
8.2.1 Comparison with air temperature
8.2.2 Wet refractivity variation and sunshine duration
8.2.3 Dew point temperature and atmospheric water vapor
8.3 Aspects of changing temporal resolution
8.4 Investigations in near real-time analysis
8.4.1 Processing real-time GPS orbits
8.4.2 Examination of time correlation strategies
9 ConclusionsNuméro de notice : 15512 Affiliation des auteurs : non IGN Autre URL associée : URL ETH Zurich Thématique : POSITIONNEMENT Nature : Thèse étrangère DOI : 10.3929/ethz-a-005648120 En ligne : https://www.sgc.ethz.ch/sgc-volumes/sgk-76.pdf Format de la ressource électronique : URL Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=62745 Exemplaires(1)
Code-barres Cote Support Localisation Section Disponibilité 15512-01 30.83 Livre Centre de documentation Géodésie Disponible
Titre : Ionospheric modeling for precise GNSS applications Type de document : Thèse/HDR Auteurs : Yahya Memarzadeh, Auteur Editeur : Delft : Netherlands Geodetic Commission NGC Année de publication : 2009 Collection : Netherlands Geodetic Commission Publications on Geodesy, ISSN 0165-1706 num. 71 Importance : 208 p. Format : 17 x 24 cm ISBN/ISSN/EAN : 978-90-6132-314-3 Note générale : Bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Géodésie spatiale
[Termes IGN] antenne GNSS
[Termes IGN] correction ionosphérique
[Termes IGN] double différence
[Termes IGN] modèle ionosphérique
[Termes IGN] positionnement différentiel
[Termes IGN] positionnement par GNSS
[Termes IGN] précision centimétrique
[Termes IGN] propagation du signal
[Termes IGN] propagation ionosphérique
[Termes IGN] simple différence
[Termes IGN] temps réel
[Termes IGN] teneur totale en électrons
[Termes IGN] traitement de données GNSSIndex. décimale : 30.61 Systèmes de Positionnement par Satellites du GNSS Résumé : (Auteur) The main objective of this thesis is to develop a procedure for modeling and predicting ionospheric Total Electron Content (TEC) for high precision differential GNSS applications. As the ionosphere is a highly dynamic medium, we believe that to have a reliable procedure it is necessary to transfer the high temporal resolution GNSS network data into the spatial domain. This objective led to the development of a recursive physics-based model for the regular TEC variations and an algorithm for real-time modeling of the medium-scale Traveling Ionospheric Disturbances (MS-TID). The research described in this thesis can roughly be divided into three parts.
The main application of these developments can be found in Network RTK. Network-RTK is a technique based on a network of reference receivers to provide cm-level positioning accuracy in real time for users in the field. To get centimeter accuracy after a short (minutes) initialization period the ionospheric delay for the user's receiver needs to be predicted very precisely between the ionospheric pierce points of the reference receivers at the double difference level. Having the cm-level accuracy in the ionospheric interpolation is crucial for the carrier phase ambiguity resolution by the user. To achieve high precision in the ionospheric interpolation, regular and irregular variability of TEC in time and space should be taken into account. The regular TEC variation, which can reach several hundreds TEC units, is mainly a function of solar zenith angle. The irregular (or non-repeatable) variations are mainly wavelike effects associated with Traveling Ionospheric Disturbances (TID).
Although TID effects on the TEC are of the order of 0.1 TEC unit, MS-TIDs, with a typical wavelength less than a few hundred kilometers, is one of the main obstacles for accurate spatial interpolation of ionospheric induced delays in a medium-scale reference GPS network. Since most of interpolation methods either use spatial linear (or quadratic) interpolation or fit a lower-order surface, the methods are not capable to model the phase-offset, caused by MS-TIDs, at distinct ionospheric pierce points. There are two major complications. Firstly, interpolation must be done at the double-difference level, which involves taking single differences between ionospheric delays for the same satellite between two different receivers, followed by differencing single differences for different satellites. This means that two different patches of the ionosphere are involved, each related to a different satellite, and each possibly associated with different TIDs. Secondly, for operational network RTK, a real-time strategy for TID detection and modeling is needed.
In the first part the performance of several empirical ionosphere models for the regular TEC variation, such as Klobuchar, NeQuick, and the IGS Global Ionosphere Maps (GIM) are studied in the mid-latitude region using GPS data. Our results show that the GIM was able to correct the absolute slant ionospheric delay to better than 80% under different geomagnetic conditions of the ionosphere. The NeQuick model, which performed better than the Klobuchar model, could correct about 60% of the slant ionospheric delay. NeQuick is a real-time ionospheric correction model for the future European Galileo navigation system. A key input parameter for NeQuick is the effective ionization parameter (Az), which will be provided as a second order polynomial in the Galileo broadcast message to single-frequency users. The coefficients of the polynomial will be estimated daily from at least 20 permanent Galileo monitoring stations. As Galileo is under development, we propose an alternative approach for estimating Az using Global Ionospheric Maps (GIM). The main advantages of the alternative approach over the standard approach are: (1) the alternative approach is more reliable, because, each IGS GIM is based on data of up to 300 GNSS stations world-wide and each IGS GIM is the combination of results of up to four analysis centers, (2) the coefficients are more representative for all regions on the world because they are computed from a world-wide grid instead of about 20 distinct locations, (3) with the alternative procedure it is possible to provide Az in a different representation, for instance using a higher order polynomial, grid, or other function types, and (4) the computational effort is much smaller assuming the IGS GIMs have already been computed.
In the second part a normal ionosphere is defined using Chapman's ion production theory to approximate the regular variability of the Earth's ionosphere. The normal ionosphere consists of lower and upper region. The lower region is formed in a photochemical equilibrium resulting in a Chapman layer. The upper region is formed in a diffusive equilibrium, whilst ignoring the geomagnetic field, resulting in a new Chapman like ionospheric layer. Integration of the continuity equation of the normal ionosphere over height leads to a Boundary Value Problem (BVP) for the temporal evolution of VTEC. Solution of the BVP results in a novel recursive model for the regular TEC variation as a function of solar zenith angle. The main motivation for developing this model is that the empirical models of the first part were either ill-suited or too complicated to model and predict the regular variation of TEC for high precision differential GNSS applications. The performance of the new model is tested at local and global scales using GIM. In general, despite the geomagnetic field was ignored, the cases analyzed show that the model gives a good overall representation of the regular variation of VTEC in the mid-latitude region under a geomagnetically quiet ionosphere. This is an important result that shows the potential of the model for a number of applications. Since the model has a recursive form it is ideally suited to use as time update equation in a dynamic data processing or Kalman filter. Another application is to use it for removing the geometry-dependent trend from time series of GPS-provided ionospheric delays to provide a pure TID observation, which is carried out in the third part of this thesis.
In the third part, a new algorithm for the real-time detection and modeling of MS-TID effects is developed. In order to eliminate effects from large-scale TIDs, the algorithm uses between-receiver single-difference (SD) ionospheric delays in a medium scale GPS network. Although single-differencing also eliminates to some extend the geometry-dependent trend, the remaining part cannot be neglected. In this thesis, we fit the SD data to the recursive model which was developed in the second part of the thesis. Any wavelike fluctuations in the data with respect to the model are assumed to be from MS-TID effects. The detrended SD data are the main input of the algorithm. The algorithm consists of six steps: initialization, detection, scraping, cross-correlation, parameter estimation, and ending. A MS-TID is assumed to be a planar longitudinal traveling wave with spatially independent amplitude that propagates in an ionospheric patch. All characteristic parameters of the MS-TID wave (e.g. period, phase velocity, propagation direction, and amplitude) are considered to be time dependent, while the Doppler-shift caused by the satellite motion is taken into account in the estimation step. The performance of the algorithm is tested with GPS data from a network. Although real TIDs are not perfect waves, the algorithm was able to model (in time and in space) the MS-TID to a large extend. The performance was found to be comparable with the Kriging interpolation method. This is an important first result, in part because these two methods are based on different principles, but also because there is still room for improvement in our algorithm. With our physics based model it is possible to avoid the planar wave approximation and take the phase-offset of the wave into account, something which is not possible with Kriging.Note de contenu : Curriculum Vitae Acknowledgments Notation and Symbols Acronyms
1 Introduction
1.1 Background
1.2 Research objectives
1.3 Outline of the thesis
1.4 Contributions of this research
2 The Earth's Atmosphere, Sun, and Geomagnetism
2.1 The Earth's Atmosphere .
2.1.1 Pressure, temperature and density variations
2.1.2 Diffusive equilibrium
2.1.3 Upper atmosphere .
2.2 The Sun
2.2.1 The Solar radiation
2.2.2 Variation of the radiation intensity
2.2.3 Solar radiations index (F10.7) .
2.3 Geomagnetism .
2.3.1 The earth's magnetic dipole field
2.3.2 The real geomagnetic field
2.3.3 Geomagnetic storm
2.3.4 Geomagnetic indices
3 Physics of the Earth's Ionosphere
3.1 Interaction of solar radiation with the Earth's upper atmosphere
3.2 Ionosphere formation theory
3.2.1 Plasma continuity equation
3.2.2 Ion production
3.2.3 Ion and electron disappearance .
3.2.4 Chapman layer
3.3 Transport process in the ionosphere .
3.3.1 Charged particle motion in a magnetic field .
3.3.2 Plasma diffusion .
3.3.3 Thermospheric wind .
3.3.4 Electromagnetic drift
3.4 Ionospheric stratification .
3.4.1 The D-Region
3.4.2 The E-Region
3.4.3 The F-Region
3.4.4 The topside region and the protonosphere .
3.4.5 Vertical electron density profile of the ionosphere
3.4.6 Characteristic parameters of the ionospheric regions
3.5 Spatial and temporal variability of the ionosphere
3.5.1 Regular variations
3.5.2 Geomagnetic regions .
3.6 Solar disturbances
3.6.1 Ionospheric disturbances .
3.6.2 Atmospheric gravity waves
3.6.3 Traveling ionospheric disturbances
4 Ionospheric delay measured from GNSS
4.1 Global Navigation Satellite Systems (GNSS) .
4.2 GNSS observation equations
4.2.1 Code or pseudo-range observation equation
4.2.2 Carrier beat phase observation equation
4.2.3 Simplifications of the observation equations
4.2.4 Tropospheric effects
4.3 Ionospheric propagation of GNSS signals .
4.3.1 Inhomogeneity of the ionosphere .
4.3.2 Dispersivity of the ionosphere .
4.3.3 Anisotropy of the ionosphere .
4.3.4 Ionospheric refractive index
4.3.5 Ionospheric first-, higher-order and bending effects . .
4.4 Ionospheric Total Electron Content (TEC)
4.4.1 A single-layer ionosphere approximation
4.4.2 Approximation of the higher-order and bending effects
4.5 Ionospheric models
4.5.1 Klobuchar model
4.5.2 Global Ionosphere Maps
4.6 Slant ionospheric delay measurements from GNSS
4.6.1 Network processing
4.6.2 Geometry-free linear combination 4.7 Summary
5 NeQuick 3D Ionospheric Electron Density Profiler
5.1 Ionospheric electron density model NeQuick
5.1.1 NeQuick model formulation for the bottom side (h < hmaXtF2)
5.1.2 NeQuick model formulation for the top side (hmax,F2 < /')
5.2 Characteristic parameters of the anchor points
5.2.1 Peak height of the F'2 region
5.2.2 Thickness parameters of the semi-Epstein layers
5.3 Providing the ionosonde parameters for NeQuick .
5.3.1 CCIR maps of /0F2 and M(3000)F2
5.3.2 Diagrammatic presentation of NeQuick
5.4 NeQuick for the Galileo navigation system
5.4.1 Effective Ionization Level (Az parameter) .
5.4.2 Estimation of the effective ionization level (nominal approach)
5.4.3 Improved version of NeQuick .
5.5 Estimation of the effective ionization level using GIM .
5.5.1 Estimation of the effective ionization level (alternative approach
5.5.2 Daily grid-based map of the effective ionization level
5.5.3 Az parameter for single point positioning .
5.6 Validation of the alternative approach .
5.6.1 Consistency of the approaches .
5.6.2 Modeling the spatial dependency of the Az parameter
5.6.3 Correlation between Az and F10.7
5.7 Performance of the NeQuick ionospheric model
5.7.1 Data specifications and processing
5.7.2 Comparison between the model errors .
5.8 Concluding remarks ..
6 Physics-Based Modeling of TEC
6.1 Normal ionosphere
6.1.1 Vertical electron density profile in the normal ionosphere . . . .
6.1.2 VTEC in the normal E-region .
6.1.3 VTEC in the normal F-region .
6.1.4 Combined VTEC of the normal ionosphere
6.1.5 Slant TEC in the normal ionosphere
6.2 Recursive model of VTEC in the normal ionosphere
6.2.1 Parametrization of the VTEC model .
6.2.2 Providing the model parameters
6.2.3 Functional model for estimating the parameters
6.2.4 Linearization of the functional model .
6.2.5 Least-squares solution of the model parameters
6.3 Performance of the VTEC model .
6.3.1 Local test of the VTEC model .
6.3.2 Global test of the VTEC model .
6.3.3 Applications of the VTEC model 6.4 Summary
7 Real-Time Modeling for Medium-Scale TID
7.1 Introduction
7.2 Medium-Scale Traveling Ionospheric Disturbances
7.3 Mechanical longitudinal wave equation
7.3.1 Traveling plane wave
7.3.2 Standing plane wave
7.4 GPS-provided TID observation .
7.4.1 Geometry-dependent trend of slant ionospheric delay
7.4.2 TID observation
7.4.3 Single-difference TID observation .
7.4.4 Double-difference TID observation .
7.5 TID observation equation .
7.5.1 Doppler-shift on TID observation .
7.6 Estimation of TID wave parameters
7.6.1 Period determination
7.6.2 TID wave vector determination
7.6.3 TID wave amplitude determination
7.7 Real-Time Medium-scale TID modeling
7.7.1 Initialization step
7.7.2 TID detection and scraping steps .
7.7.3 Cross correlation step .
7.7.4 TID parameter estimation .
7.7.5 TID ending .
7.7.6 Flowchart of the Real-Time TID modeling algorithm
7.7.7 Dependency on reference baseline .
7.7.8 Sensitivity to temporal resolution .
7.8 Implementation of the Real-Time TID modeling .
7.8.1 Case study: PRN 02
7.8.2 Case study: PRN 08
7.9 Conclusions and remarks
8 Conclusions and recommendations
8.1 Estimation of effective ionization for NeQuick .
8.2 Spatial and temporal variation of effective ionization level .
8.3 Performance of global TEC models
8.4 Model of temporal evolution of VTEC .
8.5 Modeling Medium-Scale Traveling Ionospheric Disturbances
Bibliography
IndexNuméro de notice : 15510 Affiliation des auteurs : non IGN Thématique : POSITIONNEMENT Nature : Thèse étrangère DOI : sans En ligne : https://www.ncgeo.nl/downloads/71Memarzadeh.pdf Format de la ressource électronique : URL Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=62743 Exemplaires(1)
Code-barres Cote Support Localisation Section Disponibilité 15510-01 30.61 Livre Centre de documentation Géodésie Disponible Double differencing / Huibert-Jan Lekkerkerk in Geoinformatics, vol 11 n° 6 (01/09/2008)
[article]
Titre : Double differencing Type de document : Article/Communication Auteurs : Huibert-Jan Lekkerkerk, Auteur Année de publication : 2008 Article en page(s) : pp 30 - 31 Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Navigation et positionnement
[Termes IGN] BeiDou
[Termes IGN] double différence
[Termes IGN] Galileo
[Termes IGN] Global Navigation Satellite System
[Termes IGN] Global Orbitography Navigation Satellite System
[Termes IGN] positionnement cinématique en temps réel
[Termes IGN] positionnement par GalileoRésumé : (Auteur) While researchers from Delft University have annouced the first double-difference measurements from Galileo satellites, the United States is proposing to discontinue the L1 and the L2 P (Y) codes that are currently being used by almost all commercial RTK receivers. Copyright GEOinformatics Numéro de notice : A2008-343 Affiliation des auteurs : non IGN Thématique : POSITIONNEMENT Nature : Article DOI : sans Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=29336
in Geoinformatics > vol 11 n° 6 (01/09/2008) . - pp 30 - 31[article]Exemplaires(1)
Code-barres Cote Support Localisation Section Disponibilité 262-08061 SL Revue Centre de documentation Revues en salle Disponible Galileo down to the millimeter: analyzing a GIOVE-A-B double difference / Christian Tiberius in Inside GNSS, vol 3 n° 6 (September 2008)
[article]
Titre : Galileo down to the millimeter: analyzing a GIOVE-A-B double difference Type de document : Article/Communication Auteurs : Christian Tiberius, Auteur ; Hans van der Marel, Auteur ; Jean-Marie Sleewaegen, Auteur ; et al., Auteur Année de publication : 2008 Article en page(s) : 5 p. ; pp 40 - 44 Note générale : Bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Géodésie spatiale
[Termes IGN] constellation Galileo
[Termes IGN] données Galileo
[Termes IGN] double différence
[Termes IGN] phase GNSS
[Termes IGN] résolution d'ambiguïté
[Termes IGN] traitement de données GNSSRésumé : (Editeur) With only two spacecraft in orbit for the Galileo constellation that will eventually have 30 satellites, having enough observation time to track and analyze the new signals can pose a challenge. Using a short baseline set-up and a late-night session, however, these authors were able to collect simultaneous measurements from both satellites, perform a double-difference resolution of the carrier phase cycle ambiguity, and assess the measurement noise. Copyright Gibbons Media & Research LLC Numéro de notice : A2008-680 Affiliation des auteurs : non IGN Thématique : POSITIONNEMENT Nature : Article DOI : sans Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=33532
in Inside GNSS > vol 3 n° 6 (September 2008) . - 5 p. ; pp 40 - 44[article]Documents numériques
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