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Precise point positioning with GPS: A new approach for positioning, atmospheric studies, and signal analysis / Rodrigo Figueiredo Leandro (2009)

Public 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, Canada Langues : 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 multiple Résumé : (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 recommendations Numéro 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

The GPS L2C signal: a preliminary analysis of data quality / Rodrigo Figueiredo Leandro in GPS world, vol 19 n° 10 (October 2008)

Public [article]  inGPS world > vol 19 n° 10 (October 2008) . - pp 42 - 47 Titre : The GPS L2C signal: a preliminary analysis of data quality Type de document : Article/Communication Auteurs : Rodrigo Figueiredo Leandro, Auteur ; R.B. Langley, Auteur ; et al., Auteur Année de publication : 2008 Article en page(s) : pp 42 - 47 Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Géodésie spatiale [Termes IGN] longueur d'onde [Termes IGN] qualité des données [Termes IGN] signal GPS [Termes IGN] utilisateur civil Résumé : (Auteur) 56 and counting. That's the number of GPS satellites that have been launched over the past thirty years beginning with the first prototype {Block I) satellite, space vehicle number 1, in February 1978. Ten Block I satellites were successfully launched between 1978 and 1985 to demonstrate the feasibility of GPS. The first satellite of the Block II operational constellation was launched in February 1989. The four year hiatus in launches was due, in part, to the Space Shuttle Challenger disaster as it had been planned to launch the operational satellites using the Shuttle. Following the accident, it was decided to continue with expendable rockets for GPS launches but to switch to the newly designed Delta II rocket. The pace of Block II launches was rapid with five launches of the original Block II design in 1989 and four in 1990 a modified, version of the Block II satellite - the IIA - was develloped, and between 1990 and 1997,19 Block IIAs were launched. The Block II and IIA satellites established the operational GPS constellation. Full operational capability was declared on April 27,1995. A new satellite was developed for replenishing the constellation as the earlier satellites were retired. Following an initial launch failure, twelve of the Block lIR satellites were launched between 1997 and 2004. All of the satellites in the Block I, Block II, Block IIA, and Block llR, constellations transmitted what are now called the legacy signals : tne C/A-code on the L1 frequency of 1575.42 MHz and the P-code on L1 and the L2 frequency of 1227.60 MHz.The P-code has been encrypted to yield the Y-code since January 1994, denying its direct access by most civil users. Since the C/A-code was only transmitted on the L1 frequency, civil users have had to rely on suboptimal semicodeless techniques for the dual-frequency operation necessary for direct cancellation of ionospheric biases. In 1998, Vice-President Al Gore announced that a new civil signal on L2 would be transmitted by future GPS satellites. This new signal-L2C-joined the legacy signals beginning with the launch of modernized Block llR satellite. Six of these blockllR-M satellites have been launched to date. In this month's column, we'll overview the characteristics of the new L2C signal and take a look at some of the analyses of received signals carried out by a team of researchers from the University of New Brunswick. Copyright Questex Media Group Inc Numéro de notice : A2008-397 Affiliation des auteurs : non IGN Thématique : POSITIONNEMENT Nature : Article DOI : sans Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=29390 [article]

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Brainy positioning: processing GPS data with neural networks / Rodrigo Figueiredo Leandro in GPS world, vol 18 n° 9 (September 2007)

Public [article]  inGPS world > vol 18 n° 9 (September 2007) . - pp 60 - 65 Titre : Brainy positioning: processing GPS data with neural networks Type de document : Article/Communication Auteurs : Rodrigo Figueiredo Leandro, Auteur ; C. Da Silva, Auteur ; P. Segantine, Auteur ; M.C. Santos, Auteur Année de publication : 2007 Article en page(s) : pp 60 - 65 Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Géodésie spatiale [Termes IGN] phase GPS [Termes IGN] positionnement par GPS [Termes IGN] réseau neuronal artificiel [Termes IGN] simulation [Termes IGN] temps réel [Termes IGN] traitement de données GNSS Résumé : (Editeur) The brain is a fascinating organ. [...] In an effort to better understand how the brain works, neuroscientists teamed up with computer scientists to develop mathematical models to describe how networks of interconnected neurons process information. By the late 1950s, they had arrived at a basic model which has been improved on over the years. Each neuron in the network performs a simple computation; it receives signals from its input links, which it weights and then uses to compute its activation level (or output). The success of neural network models to mimic the basic operation of brain cells led computer scientists to the idea that artificial neural networks could be used to solve mathematical problems. They were able to show that, through a training or learning process, such networks are capable of solving virtually any problem that involves mapping input data to output data. Artificial neural networks have served as the basis for a variety of a tasks ranging from intelligent simulation, to real-time adaptation, to data analysis. While not a direct replacement for our traditional least-squares and Kalman filtering techniques, artificial neural networks have been used effectively for a number of applications in geodesy and navigation, including the processing of GPS data. But the handling of GPS data for use in a neural network processor is not without problems. In this month's column, we take a look at how artificial neural networks can be used as a tool in GPS applications, including the preprocessing necessary to successfully ingest the data. Copyright Questex Media Group Inc Numéro de notice : A2007-444 Affiliation des auteurs : non IGN Thématique : POSITIONNEMENT Nature : Article DOI : sans Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=28807 [article]

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Stochastic models for GPS positioning: an empirical approach / Rodrigo Figueiredo Leandro in GPS world, vol 18 n° 2 (February 2007)

Public [article]  inGPS world > vol 18 n° 2 (February 2007) . - pp 50 - 56 Titre : Stochastic models for GPS positioning: an empirical approach Type de document : Article/Communication Auteurs : Rodrigo Figueiredo Leandro, Auteur ; M.C. Santos, Auteur Année de publication : 2007 Article en page(s) : pp 50 - 56 Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Géodésie spatiale [Termes IGN] antenne GPS [Termes IGN] matrice de covariance [Termes IGN] mesurage de pseudo-distance [Termes IGN] modèle stochastique [Termes IGN] perturbation [Termes IGN] positionnement par GPS [Termes IGN] qualité des données [Termes IGN] résidu Résumé : (Editeur) When processing GPS data, we should not only try to model the deterministic part of the measurements ; we should also try to account for their stochastic behavior, which is possible through use of the covariance matrix. Here, the authors present an empirical approach for building the covariance matrix of observations, with the ultimate goal to improve the quality of GPS data processing. Copyright Questex Media Group Inc Numéro de notice : A2007-070 Affiliation des auteurs : non IGN Thématique : POSITIONNEMENT Nature : Article DOI : sans Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=28435 [article]

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067-07021	RAB	Revue	Centre de documentation	En réserve L003	Disponible