Ara es mostren els items 1-20 de 125

  • A linear scale height Chapman model supported by GNSS occultation measurements 

    Olivares Pulido, German; Hernández Pajares, Manuel; Aragón Ángel, Maria Angeles; García Rigo, Alberto (2016-05)
    Comunicació de congrés
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    Global Navigation Satellite Systems (GNSS) radio occultations allow the vertical sounding of the Earth's atmosphere, in particular, the ionosphere. The physical observables estimated with this technique permit to test ...
  • A review of higher order ionospheric refraction effects on dual frequency GPS 

    Petrie, Elisabeth J.; Hernández Pajares, Manuel; Spalla, Paolo; Moore, Philip; King, Matt A. (2010-11-26)
    Article
    Accés restringit per política de l'editorial
    Abstract Higher order ionospheric effects are increasingly relevant as precision requirements on GPS data and products increase. The refractive index of the ionosphere is affected by its electron content and the magnetic ...
  • Assessment of the F2-layer electron density peak inferred from Formosat-3/COSMIC radio occultations over half a Solar Cycle 

    Aragon-Angel, Angela; Limberger, Marco; Hernández Pajares, Manuel; Altadill, David; Dettmering, Denise (2016)
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    GNSS radio occultation (RO) measurements have become crucial to provide valuable information on the vertical electron density structure of the Ionosphere. Ionospheric key parameters such as the maximum electron density ...
  • Characterization and modelling of the ionosphere for EGNOS development and qualification 

    Schlüter, S.; Prieto Cerdeira, Roberto; Orús Pérez, Raul; Lam, J.P.; Juan Zornoza, José Miguel; Sanz Subirana, Jaume; Hernández Pajares, Manuel (2013)
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    The availability of representative data samples, models and statistical information derived from the analysis of parameters that adequately describe the state of the ionosphere are key elements for the design, verification ...
  • Classifing stars: a comparison between clasical, genetic and neural network algorithms 

    Hernández Pajares, Manuel; Comellas Padró, Francesc de Paula; Monte Moreno, Enrique (F. MURTAGH AND A. HECK, 1992)
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  • Comparative testing of four ionospheric models driven with GPS measurements 

    Zandbergen, R.; Feltens, Joachim; Angling, M; Jackson Booth, N; Jakowski, Norbert; Hoque, Mainul; Hernández Pajares, Manuel; Aragón Ángel, María Ángeles; Orús Pérez, Raül (2011-07-28)
    Article
    Accés obert
    In the context of the European Space Agency/European Space Operations Centre funded Study “GNSS Contribution to Next Generation Global Ionospheric Monitoring,” four ionospheric models based on GNSS data (the Electron ...
  • Comparing performances of seven different global VTEC ionospheric models in the IGS context 

    Hernández Pajares, Manuel; Roma Dollase, David; Krankowski, Andrzej; García Rigo, Alberto; Orús Pérez, Raul (International GNSS Service (IGS), 2016)
    Text en actes de congrés
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    A summary of the main concepts on Global Ionospheric Map(s) (hereinafter GIM(s)) of Vertical Electron Content (VTEC), with special emphasis on their assessment, is presented in this paper. It is based on the experience ...
  • Comprehensive ionospheric delay modelling for single-frequency GNSS precise positioning: first steps 

    Colombo, Oscar L.; Hernández Pajares, Manuel; Janssen, Volker; García Rigo, Alberto (International GNSS Service (IGS), 2016)
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  • Consistency of seven different GNSS global ionospheric mapping techniques during one solar cycle 

    Roma Dollase, David; Hernández Pajares, Manuel; Krankowski, Andrzej; Kotulak, Kacper; Ghoddousi Fard, Reza; Yuan, Yunbin; Li, Zishen; Zhang, Hongping; Shi, Chuang; Wang, Cheng; Feltens, Joachim; Vergados, Panagiotis; Komjathy, Attila; Schaer, Stefan C.; García Rigo, Alberto; Gómez Cama, José Mª (2017-11-28)
    Article
    Accés obert
    In the context of the International GNSS Service (IGS), several IGS Ionosphere Associated Analysis Centers have developed different techniques to provide global ionospheric maps (GIMs) of vertical total electron content ...
  • Correlation studies for B-spline modeled F2 Chapman parameters obtained from FORMOSAT-3/COSMIC data 

    Limberger, Marco; Liang, W; Schmidt, Michael; Dettmering, D; Hernández Pajares, Manuel; Hugentobler, U (2014)
    Article
    Accés obert
    The determination of ionospheric key quantities such as the maximum electron density of the F2 layer NmF2, the corresponding F2 peak height hmF2 and the F2 scale height HF2 are of high relevance in 4-D ionosphere modeling ...
  • Definition of an SBAS ionospheric activity indicator and its assessment over Europe and Africa During the last solar cycle 

    Sanz Subirana, Jaume; Juan Zornoza, José Miguel; Hernández Pajares, Manuel; Prieto Cerdeira, Roberto; Schlueter, Stefan (2013)
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    In this work, an ionospheric activity indicator is defined based in the “weighted” Along Arc TEC rate (AATR). It is shown that this indicator, which can be easily computed from the GPS carrier phases, is well correlated ...
  • Direct determination of electron density profiles from GNSS occulttion data 

    Aragón Ángel, María Ángeles; Hernández Pajares, Manuel; Miguel Juan, Miguel; Sanz Subirana, Jaume; Ramos Bosch, Pedro (2008-08-07)
    Comunicació de congrés
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  • Direct MSTID mitigation in precise GPS processing 

    Hernández Pajares, Manuel; Wielgosz, Pawel; Paziewski, Jacek; Krypiak-Gregorczyk, Anna; Krukowska, Marta; Stepniak, Katarzyna; Kaplon, Jan; Hadas, Tomasz; Sosnica, Krzysztof; Bosy, Jaroslaw; Orús Pérez, Raul; Monte Moreno, Enrique; Yang, Heng; García Rigo, Alberto; Olivares Pulido, German (2017-03)
    Article
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    In this paper, the authors summarize a simple and efficient approach developed to mitigate the problem in precise GNSS positioning originated by the most frequent ionospheric wave signatures: the Medium Scale Travelling ...
  • Distribution and mitigation of higher-order ionospheric effects on precise GNSS processing 

    Hernández Pajares, Manuel; Aragón Ángel, María Ángeles; Defraigne, Pascale; Bergeot, Nicolas; Prieto Cerdeira, Roberto; García Rigo, Alberto (2014-04)
    Article
    Accés obert
    Higher-order ionospheric effects (I2+) are one of the main limiting factors in very precise Global Navigation Satellite Systems (GNSS) processing, for applications where millimeter accuracy is demanded. This paper summarizes ...
  • Enhanced precise point positioning for GNSS users 

    Juan Zornoza, José Miguel; Hernández Pajares, Manuel; Sanz Subirana, Jaume; Ramos Bosch, Pedro; Aragón Ángel, María Ángeles; Orus, R.; Ochieng, W.; Feng, S; Jofre, Martí; Coutinho, P; Samson, Jaron; Tossaint, Michel Mathias Maria (Institute of Electrical and Electronics Engineers (IEEE), 2012-09-21)
    Article
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    This paper summarizes the main results obtained during the development of an Enhanced Precise Point Positioning (EPPP) Global Navigation Satellite Systems multifrequency user algorithm. The main innovations include the ...
  • EVA: GPS-based extended velocity and acceleration determination 

    Salazar Hernández, Dagoberto José; Hernández Pajares, Manuel; Juan Zornoza, José Miguel; Sanz Subirana, Jaume; Aragón Ángel, María Ángeles (2010-12-01)
    Article
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    In this work, a new GPS carrier phase-based velocity and acceleration determination method is presented that extends the effective range of previous techniques. The method is named ‘EVA’, and may find applications in ...
  • Evaluation of the ionospheric F2 characteristics inferred from radio occultations exploiting the availability of FORMOSAT-3/COSMIC data over half a solar cycle 

    Aragón Ángel, Maria Angeles; Limberger, Marco; Hernández Pajares, Manuel; Altadill, David; Erdogan, Eren; Schmidt, Michael (ION Publications (The Institute of navigation), 2016)
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    This contribution presents the assessment, on both the maximum electron density (NmF2) and the corresponding peak height of the F2 layer (hmF2), of the overall performance of such ionospheric key parameters inferred from ...
  • Extended version. Occurrence of solar flares viewed with GPS: statistics and fractal nature 

    Monte Moreno, Enrique; Hernández Pajares, Manuel (2014-09-05)
    Report de recerca
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    In this paper we describe the statistical properties of the EUV solar flux sudden variation. The solar flux variation is modeled as a time series characterized by the subsolar VTEC (Vertical Total Electron Content) ...
  • Fast LAMBDA-based ambiguity resolution combined with WARTK technique for Galileo data simulated using ESA's Galileo Signal Validation Facility 

    Odijk, Dennis; De Bakker, Peter; Verhagen, Sandra; Teunissen, Peter J. G.; Hernández Pajares, Manuel; Samson, Jaron (2009-12)
    Text en actes de congrés
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    This contribution addresses the effect of having a triple frequency Global Navigation Satellite System (GNSS) on ambiguity resolution of long baselines, i.e. baselines for which the differential ionospheric delays cannot ...
  • Fast Precise Point Positioning based on real-time ionospheric modelling 

    Juan Zornoza, José Miguel; Hernández Pajares, Manuel; Sanz Subirana, Jaume; Samson, Jaron; Tossaint, Michel Mathias Maria (2012)
    Comunicació de congrés
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    Summary of main results of new technique Fast Precise Point Positioning developed in the framework of the “Enhanced Precise Point Positioning (EPPP) GNSS multifrequency user algorithm” ESA funded project. -The precise ...