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Visualization, statistical analysis, and mining of historical vessel data / Sabarish Senthilnathan Muthu (2015)
Titre : Visualization, statistical analysis, and mining of historical vessel data Type de document : Mémoire Auteurs : Sabarish Senthilnathan Muthu, Auteur Editeur : Fredericton [Canada] : University of New Brunswick Année de publication : 2015 Collection : Technical report num. 296 Importance : 150 p. Format : 21 x 30 cm Note générale : bibliographie
M.Sc.E. thesis, Department of Geodesy and Geomatics EngineeringLangues : Anglais (eng) Descripteur : [Termes IGN] données spatiotemporelles
[Termes IGN] Egée, mer
[Termes IGN] interface web
[Termes IGN] navire
[Termes IGN] site Natura 2000
[Termes IGN] trajectoire (véhicule non spatial)
[Vedettes matières IGN] GéovisualisationRésumé : (auteur) An important area of research in marine information systems is the management and analysis of the large and increasing amount maritime spatio-temporal datasets. There are a lack of systems that may provide visualization and clustering techniques for large spatiotemporal datasets (Oliveira, 2012). This thesis describes the design and implementation of a prototype web-based system for visualizing, computing statistics, and detecting outliers of moving vessels over a massive set of historic AIS data from the Aegean Sea in the Mediterranean. This historic AIS data was acquired from the Marine Traffic project (Marine Traffic, 2014) which collects the raw location points of the vessels. The web-based system provides the following functionalities: (i) user interface to upload the location points of vessels into a database, (ii) detailed and simplified trajectory construction of the uploaded location points of vessels, (iii) distance, speed, direction, and turn angle computation of the constructed trajectories, (iv) identify vessels that intersect the European Union’s Natura 2000 protected areas, (v) identify spatio-temporal outliers in the location points of vessels using DBSCAN algorithm, and (vi) heat map visualization to show the traffic load and highlight sea zones of high risk. The architecture of the web-based system employed is based on open standards, and allows for interoperable data access. The system was implemented using PHP as the server-side scripting language, and Google Maps API as the client-side scripting language. Furthermore, improved system responsiveness, and server performance was achieved by asynchronous interaction between client and server by utilizing AJAX to send and receive requests. In addition, data transfer between client and server was achieved using the platform-independent and light weight JSON format. Numéro de notice : 14918 Affiliation des auteurs : non IGN Thématique : GEOMATIQUE Nature : Mémoire masters divers En ligne : http://www2.unb.ca/gge/Pubs/TR296.pdf Format de la ressource électronique : URL Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=76912
Titre : Improved convergence for GNSS precise point positioning Type de document : Thèse/HDR Auteurs : Simon Banville, Auteur Editeur : Fredericton [Canada] : University of New Brunswick Année de publication : 2014 Collection : Technical report num. 294 Importance : 293 p. Format : 21 x 30 cm Note générale : bibliographie
dissertation submitted in partial fulfillment of the requirements for the degree of Doctor of Philosophy in the Department of Geodesy and Geomatics EngineeringLangues : Anglais (eng) Descripteur : [Termes IGN] ambiguïté entière
[Termes IGN] correction ionosphérique
[Termes IGN] erreur systématique
[Termes IGN] mesurage de phase
[Termes IGN] phase GNSS
[Termes IGN] positionnement ponctuel précis
[Termes IGN] précision centimétrique
[Termes IGN] signal GLONASS
[Termes IGN] teneur totale en électrons
[Vedettes matières IGN] Traitement de données GNSSRésumé : (auteur) The precise point positioning (PPP) methodology allows for cm-level positioning accuracies using a single GNSS receiver, through careful modelling of all error sources affecting the signals. Adoption of PPP in several applications is however muted due to the time required for solutions to converge or re-converge to their expected accuracy, which regularly exceeds 30 minutes for a moving receiver. In an attempt at solving the convergence issues associated with PPP, three aspects were investigated.
First, signal tracking interruptions are typically associated with integer discontinuities in carrier-phase measurements, often referred to as a cycle slips. A refined method for detecting and correcting cycle slips was thus developed, in which all error sources affecting the observations are either modelled or estimated. Application of this technique allows for instantaneous cycle-slip correction, meaning that continuous PPP solutions can be obtained even in the presence of short losses of lock on satellites.
Second, external information on the ionosphere allows for reduced convergence times, but consistency must be observed in the functional model. A new technique, termed integer levelling, was thus developed to generate ionospheric delay corrections compatible with PPP based on the decoupled-clock model. Depending on the inter-station distances in the network providing ionospheric corrections, instantaneous cm-level accuracies can be obtained in PPP.
Third, processing of GLONASS signals is more problematic than GPS due to frequency division multiple access, leading to inter-frequency carrier-phase and code biases. A novel approach for the estimation of such biases was then proposed and facilitates processing of mixed receiver types. It also allows for undifferenced GLONASS ambiguity resolution based on a heterogeneous network of stations, the first demonstration of such an approach, and therefore has the potential to further reduce PPP convergence times.
This research also emphasized potential benefits of integer-levelled observations for improved ionosphere monitoring. The main justifications for adopting this approach are: a reduction in the determination of slant total electron content errors, a simplification in the GLONASS processing strategy, its applicability in real time, and the generation of satellite biases required for the use of ionospheric constraints in PPP with ambiguity resolution.Note de contenu : CH. 1 INTRODUCTION
1.1 Background
1.2 Objectives, Methodology, and Contributions
1.3 Dissertation Outline
CH. 2 IMPROVING REAL-TIME KINEMATIC PPP WITH INSTANTANEOUS CYCLE-SLIP CORRECTION
2.1 Introduction
2.2 Time-Differenced Functional Model
2.3 Time-Differenced Adjustment Process
2.4 Cycle-Slip Correction Procedure
2.5 PPP Solution Update
2.6 Processing Results
2.7 Further Discussions
2.8 Summary, Conclusions, and Future Work
CH. 3 MITIGATING THE IMPACTS OF IONOSPHERIC CYCLE SLIPS ON GNSS OBSERVATIONS
3.1 Introduction
3.2 Cycle-Slip Detection and Estimation
3.3 Integer Least-Squares Theory
3.4 Stochastic Analysis
3.5 Experimental Results
3.6 Conclusion
CH. 4 MONITORING THE IONOSPHERE USING INTEGER-LEVELLED GPS MEASUREMENTS
4.1 Introduction
4.2 Standard Levelling Procedure
4.3 Integer-Levelling Procedure
4.4 Slant TEC Evaluation
4.5 VTEC Evaluation
4.6 Conclusion
CH. 5 GLOBAL AND REGIONAL IONOSPHERIC CORRECTIONS FOR FASTER PPP CONVERGENCE
5.1 Introduction
5.2 The Decoupled-Clock Model (DCM)
5.3 The Extended Decoupled-Clock Model (EDCM)
5.4 Integer Levelling
5.5 Analyzing the Accuracy of Slant Ionospheric Corrections
5.6 PPP with Global Ionospheric Corrections
5.7 Regional Ionospheric Corrections for PPP with Ambiguity Resolution
5.8 Conclusion
CH. 6 GLONASS AMBIGUITY RESOLUTION OF MIXED RECEIVER TYPES WITHOUT EXTERNAL CALIBRATION
6.1 Introduction
6.2 Defining Minimum Constraints
6.3 Datum Transformation
6.4 Estimation of GLONASS Inter-frequency Code Biases
6.5 Proof of Concept
6.6 Conclusion
CH. 7 CONCEPTS FOR UNDIFFERENCED GLONASS AMBIGUITY RESOLUTION
7.1 Introduction
7.2 Estimating Inter-Frequency Biases
7.3 Ambiguity Resolution in the Presence of Biases
7.4 Application of Concepts
7.5 Characteristics of IFCBs
7.6 Melbourne-Wübbena Satellite Biases
7.7 Conclusion
CH. 8 CONCLUSION
8.1 Summary
8.2 Recommendations
8.3 Putting it All TogetherNuméro de notice : 14916 Affiliation des auteurs : non IGN Thématique : POSITIONNEMENT Nature : Thèse étrangère Note de thèse : PhD : Geodesy and Geomatics Engineering : University of New Brunswick : 2014 En ligne : http://www2.unb.ca/gge/Pubs/TR294.pdf Format de la ressource électronique : URL Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=76904 Precise point positioning with GPS: A new approach for positioning, atmospheric studies, and signal analysis / Rodrigo Figueiredo Leandro (2009)
Titre : Precise point positioning with GPS: A new approach for positioning, atmospheric studies, and signal analysis Type de document : Thèse/HDR Auteurs : Rodrigo Figueiredo Leandro, Auteur Editeur : Fredericton [Canada] : University of New Brunswick Année de publication : 2009 Collection : Technical report num. 267 Importance : 232 p. Format : 21 x 30 cm Note générale : bibliographie
Ph.D. dissertation, Department of Geodesy and Geomatics Engineering, University of New Brunswick, Fredericton, New Brunswick, CanadaLangues : Anglais (eng) Descripteur : [Termes IGN] bruit (théorie du signal)
[Termes IGN] erreur systématique
[Termes IGN] estimation statistique
[Termes IGN] horloge atomique
[Termes IGN] modèle atmosphérique
[Termes IGN] positionnement ponctuel précis
[Termes IGN] récepteur monofréquence
[Termes IGN] retard ionosphèrique
[Termes IGN] trajet multipleRésumé : (auteur) Precise Point Positioning (PPP) is one of the existing techniques to determine point coordinates using a GPS (Global Positioning System) receiver. In this technique observations collected by a single receiver are used in order to determine the three components of the coordinates, as well as other parameters, such as the receiver clock error and total neutral atmosphere delay. The PPP technique is the subject of this thesis. The idea is that PPP could be used not only for positioning, but for a number of different tasks, as GPS data analysis. The observation model used in this technique has to take into consideration a number of effects present on GPS signals, and observations are un-differenced (there are no differences between receivers or between satellites). This makes PPP a powerful data analysis tool which is sensible to a variety of parameters. When the observation model is designed for positioning, most of these parameters (e.g., satellite clocks) are used as known quantities, but in this research the observation model was modified and enhanced to develop a PPP package that can be used as a tool for determining other parameters rather than position, receiver clock error and neutral atmosphere delay. These estimated parameters include ionospheric delay, code biases, satellite clock errors, and code multipath plus noise. Existing neutral atmosphere delay models have also been studied in this thesis, and an enhanced model has been developed and has had its performance assessed. The development of the model is based on measured meteorological parameters, and the rationale of the model is established in order to make its use as practical as possible for users of positioning techniques, such as PPP. Note de contenu : 1. Introduction
1.1. Motivation
1.2. Objectives and contributions
1.3. Outline of the thesis
2. Precise Point Positioning and GPS Analysis and Positioning Software (GAPS)
2.1. A bit of history, and GAPS’s role in PPP research and development
2.2. The positioning observation model
2.3. Observations adjustment
2.4. Corrections
3. Ionospheric delay estimation filter
3.1. Introduction
3.2. Ionospheric delay estimation filter
3.3. Results analysis
3.4. Chapter remarks
4. Estimation of code biases by means of PPP
4.1. Introduction
4.2. PPP-based P1-C1 code bias estimation
4.3. PPP-based P2-C2 code bias estimation
4.5. Chapter remarks
5. Code multipath and noise estimation with PPP
5.1. Iono-free code multipath plus noise estimates
5.2. L1 and L2 code multipath plus noise estimates
5.3. Comparison with TEQC
5.4. Analysis of L2C code quality
5.5. Chapter remarks
6. Single-receiver satellite pseudo-clock estimation
6.1. Derivation of the satellite pseudo-clocks
6.2. An example of generation and use of satellite pseudo-clocks
6.3. Chapter remarks
7. Neutral Atmosphere prediction models for GNSS positioning
7.1. Introduction
7.2. UNB wide area models
7.3. UNB wide area model for North America – UNBw.na
7.4. UNBw.na validation with ray-traced delays
7.5. Chapter remarks
8. Conclusions and recommendationsNuméro de notice : 14901 Affiliation des auteurs : non IGN Thématique : POSITIONNEMENT Nature : Thèse étrangère Note de thèse : PhD : Geodesy and Geomatics Engineering : University of New Brunswick : Canada : 2009 DOI : sans Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=76787 Modeling the neutral-atmospheric propagation delay in radiometric space techniques / Virgilio de Brito Mendes (1999)
Titre : Modeling the neutral-atmospheric propagation delay in radiometric space techniques Type de document : Thèse/HDR Auteurs : Virgilio de Brito Mendes, Auteur ; Richard B. Langley, Directeur de thèse Editeur : Fredericton [Canada] : University of New Brunswick Année de publication : 1999 Collection : Technical report num. 199 Importance : 353 p. Format : 21 x 30 cm Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Géodésie spatiale
[Termes IGN] atmosphère terrestre
[Termes IGN] lancer de rayons
[Termes IGN] modèle numérique
[Termes IGN] réfraction atmosphérique
[Termes IGN] retard troposphériqueRésumé : (auteur) The propagation delay induced by the electrically-neutral atmosphere has been recognized as the most problematic modeling error for radiometric space geodetic techniques. A mismodeling of this propagation delay affects significantly the height component of position and constitutes therefore a matter of concern in space-geodesy applications, such as sea-level monitoring, postglacial rebound measurement, earthquake-hazard mitigation, and tectonic-plate-margin deformation studies.
The neutral-atmosphere propagation delay is commonly considered as composed of two components: a "hydrostatic" component, due essentially to the dry gases of the atmosphere, and a "non-hydrostatic" component, due to water vapor. Each one can be described as the product of the delay at the zenith and a mapping function, which models the elevation angle dependence of the propagation delay.
This dissertation discusses primarily the accuracy of zenith delay prediction models and mapping functions found in the scientific literature. This performance evaluation is based on a comparison against 32,467 benchmark values, obtained by ray tracing one-year's worth of radiosonde profiles from 50 stations distributed worldwide, and comprised different phases: ray-tracing accuracy assessment, model development, and model accuracy assessment.
We have studied the sensitivity of the ray-tracing technique to the choice of physical models, processing strategies, and radiosonde instrumentation accuracy. We have concluded that errors in ray tracing can amount to a few centimetres, under special circumstances, but they largely average out for each station's time series of profiles.
In order to optimize the performance of the models, we have established databases of the temperature-profile parameters using 50 additional sites, for a total of 100 radiosonde stations. Based on these large databases, we have developed models for lapse rate and tropopause height determination, which have improved significantly the performance of models using the information.
From our model assessment we have concluded that the hydrostatic component of the zenith delay can be predicted with sub-millimeter accuracy, using the Saastamoinen model, provided accurate measurements of surface total pressure are available. The zenith non-hydrostatic component is much more difficult to predict from surface meteorological data or site dependent parameters, and the best models show values of root-mean-square (rms) scatter about the mean of a few centimetres in the zenith direction.
Notwithstanding the large number of mapping functions we have analyzed, only a small group meet the high standards of modern space geodetic data analysis: Ifadis, Lanyi, MTT, and NMF. For the total number of radiosonde stations analyzed, none of the mapping functions revealed themselves to be superior for all elevation angles. For elevation angles above 15 degrees, Lanyi, MTT, and NMF yield identical mean biases and the best total error performances. At lower elevation angles, Ifadis and NMF are clearly superior. As regards the rms scatter about the mean, Ifadis performs the best for all elevation angles, followed closely by Lanyi.Note de contenu : 1- Introduction
2- The Earth's atmosphere
3- Neutral-atmosphere refraction
4- Data description and analysis
5- Ray tracing
6- Model assessment
7- Conclusions and recommendationsNuméro de notice : 14876 Affiliation des auteurs : non IGN Thématique : POSITIONNEMENT Nature : Thèse étrangère Note de thèse : PhD : Geodesy and geomatics : University of New-Brunswick : 1998 DOI : sans En ligne : https://gge.ext.unb.ca/Pubs/TR199.pdf Format de la ressource électronique : URL Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=75930 Documents numériques
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14876 these 1998 MendesAdobe Acrobat PDF GPS satellite sky distribution / Rock Santerre (1989)
Titre : GPS satellite sky distribution : impact on the propagation of some important errors in precise relative positioning Type de document : Rapport Auteurs : Rock Santerre, Auteur Editeur : Fredericton [Canada] : University of New Brunswick Année de publication : 1989 Collection : Technical report num. 145 Importance : 203 p. Format : 21 x 28 cm Note générale : Bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Géodésie spatiale
[Termes IGN] compensation par moindres carrés
[Termes IGN] distribution spatiale
[Termes IGN] erreur systématique
[Termes IGN] GPS en mode différentiel
[Termes IGN] matrice de covariance
[Termes IGN] positionnement différentiel
[Termes IGN] positionnement par GPS
[Termes IGN] positionnement statique
[Termes IGN] propagation d'erreur
[Termes IGN] satellite GPS
[Termes IGN] traitement de données GNSSIndex. décimale : 30.61 Systèmes de Positionnement par Satellites du GNSS Numéro de notice : 56304 Affiliation des auteurs : non IGN Thématique : POSITIONNEMENT Nature : Rapport Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=43775 Réservation
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