Exploració per autor "Martín Neira, Manuel"

Ara es mostren els items 21-40 de 72

    • Faraday rotation retrieval using SMOS radiometric data 

      Corbella Sanahuja, Ignasi; Wu, Lin; Torres Canals, Francesc; Duffo Ubeda, Núria; Martín Neira, Manuel (2015-03-01)
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      Accés obert
      Faraday rotation is dynamically computed from L-band radiometric data acquired by the Soil Moisture and Ocean Salinity satellite. Improved full polarimetric image reconstruction and smart spatiotemporal filtering are used ...

    • GNSS-R altimeter based on Doppler multi-looking 

      D'Addio, Salvatore; Martín Neira, Manuel; di Bisceglie, Maurizio; Galdi, Carmela; Martín Alemany, Francisco (2014-05-01)
      Article
      Accés restringit per política de l'editorial
      Measuring ocean mesoscale variability is one of the main objectives of next generation satellite altimeters. Current radar altimeters make observations only at the nadir sub-satellite ground track, which is not sufficient ...

    • GNSS-R altimeter performance: analysis of Cramer-Rao lower bounds 

      D'Addio, Salvatore; Martín Neira, Manuel; Martín Alemany, Francisco; Hyuk, Park; Camps Carmona, Adriano José (2012)
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      Earth-reflected Global Navigation Satellite Systemsignals have become an attractive tool for remote sensing, being proposed as a means to perform ocean altimetry, among many other applications. The technique exploiting ...

    • Impact of amplitude calibration errors on SMOS global images 

      Durán Martínez, Israel; Corbella Sanahuja, Ignasi; Torres Torres, Francisco; Duffo Ubeda, Núria; Oliva, Roger; Martín Neira, Manuel (Institute of Electrical and Electronics Engineers (IEEE), 2016)
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      Some of the artifacts observed in SMOS brightness temperature images are originated in an inconsistency between correlation and antenna temperature calibration errors, which produces a multiplicative bias that scales with ...

    • Impact of correlator efficiency errors on SMOS land-sea contamination 

      Corbella Sanahuja, Ignasi; Durán Martínez, Israel; Wu, Lin; Torres Canals, Francesc; Duffo Ubeda, Núria; Khazaal, Ali; Martín Neira, Manuel (2015-09-01)
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      Accés obert
      Land-sea contamination observed in Soil Moisture and Ocean Salinity (SMOS) brightness temperature images is found to have two main contributions: the floor error inherent of image reconstruction and a multiplicative error ...

    • In-orbit validations of SMOS full polarimetric equations 

      Torres Torres, Francisco; Corbella Sanahuja, Ignasi; Wu, Lin; Duffo Ubeda, Núria; Delwart, Steven; Martín Neira, Manuel (Institute of Electrical and Electronics Engineers (IEEE), 2013)
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      This paper analyzes the consistency of SMOS fully polarimetric measurement mode by comparing measured data over the ocean with the expected results. These last are based on an accurate ocean model provided by LOCEAN and ...

    • Increasing stratification as observed by satellite sea surface salinity measurements 

      Olmedo Casal, Estrella; Turiel Martínez, Antonio; González Gambau, Verónica; González Haro, Cristina; García Espriu, Aina; Gabarró Prats, Carolina; Portabella, Marcos; Corbella Sanahuja, Ignasi; Martín Neira, Manuel; Arias Ballesteros, Manuel; Catany, Rafael; Sabia, Roberto; Olivia, Roger; Scipal, Klaus (Nature, 2022-12-01)
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      Changes in the Earth’s water cycle can be estimated by analyzing sea surface salinity. This variable refects the balance between precipitation and evaporation over the ocean, since the upper layers of the ocean are the ...

    • Integration of MIRAS breadboard and future activities 

      Martín Neira, Manuel; Goutoule, J.M.; Knight, A.; Claude, J.; Bará Temes, Francisco Javier; Camps Carmona, Adriano José; Torres Torres, Francisco; Corbella Sanahuja, Ignasi; Lannes, A.; Anterrieu, E.; Laursen, B.; Skou, N. (1996)
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      The European Space Agency (ESA) is conducting a feasibility study on MIRAS, a Microwave Imaging Radiometer using two dimensional aperture synthesis, for the mapping of soil moisture and ocean salinity from space. An aircraft ...

    • Millimeter-wave aperture synthesis for remote sensing of the Earth 

      Harvey, Andrew R.; Greenaway, Alain H.; Camps Carmona, Adriano José; Bará Temes, Francisco Javier; Torres Torres, Francisco; Corbella Sanahuja, Ignasi; Martín Neira, Manuel (1998)
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      Millimetre-wave radiometry of the earth's surface from Low Earth Orbit (LEO) with a resolution of a few km requires antenna apertures several metres across and sub-second scanning times. Fulfilling these requirements with ...

    • Millimeter-wave aperture synthesis radiometry for snow and ice mapping 

      Harvey, A.R.; Greenaway, A.H.; Camps Carmona, Adriano José; Corbella Sanahuja, Ignasi; Torres Torres, Francisco; Bará Temes, Francisco Javier; Martín Neira, Manuel (1999)
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      An outline design for a dual-band mm-wave polarimetric SAIR has been presented and is considered to be tractable. The envisaged application is for snow and ice mapping and ocean wind vector measurement. The vastly increased ...

    • MIRAS calibration and performance: results from the SMOS in-orbit commissioning phase 

      Corbella Sanahuja, Ignasi; Torres Torres, Francisco; Duffo Ubeda, Núria; González Gambau, Veronica; Pablos Hernández, Miriam; Durán Martínez, Israel; Martín Neira, Manuel (IEEE Press. Institute of Electrical and Electronics Engineers, 2011-09)
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      Accés restringit per política de l'editorial
      After the successful launching of the Soil Moisture and Ocean Salinity satellite in November 2009, continuous streams of data started to be regularly downloaded and made available to be processed. The first six months of ...

    • MIRAS end-to-end calibration: application to SMOS L1 processor 

      Vall-Llossera Ferran, Mercedes Magdalena; Corbella Sanahuja, Ignasi; Torres Torres, Francisco; Camps Carmona, Adriano José; Colliander, A; Martín Neira, Manuel; Ribó Vedrilla, Serni; Rautiainen, K; Duffo Ubeda, Núria (IEEE Press. Institute of Electrical and Electronics Engineers, 2005-05)
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      End-to-end calibration of the Microwave Imaging Radiometer by Aperture Synthesis (MIRAS) radiometer refers to processing the measured raw data up to dual-polarization brightness temperature maps over the earth's surface, ...

    • MIRAS End-to-End Calibration: Application to SMOS L1 Processor 

      Corbella Sanahuja, Ignasi; Torres Torres, Francisco; Camps Carmona, Adriano José; Colliander, Andreas; Martín Neira, Manuel; Ribó Vedrilla, Serni; Rautiainen, Kimmo; Duffo Ubeda, Núria; Vall-Llossera Ferran, Mercedes Magdalena (IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC, 2005-05-31)
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      Accés obert
      End-to-end calibration of the Microwave Imaging Radiometer by Aperture Synthesis (MIRAS) radiometer refers to processing the measured raw data up to dual-polarization brightness temperature maps over the earth's surface, ...

    • Mitigation of cross-polar antenna pattern errors in SMOS: simplified approach 

      Durán Martínez, Israel; Torres Torres, Francisco; Corbella Sanahuja, Ignasi; Duffo Ubeda, Núria; Lin, Wu; Martín Neira, Manuel (Institute of Electrical and Electronics Engineers (IEEE), 2016)
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      This paper analyzes a simplified image reconstruction method that exclusively takes into account the dominant antenna pattern terms to model image inversion artifacts and mitigate SMOS polarimetric spatial bias over the ...

    • Modeling and analysis of GNSS-R waveforms sample-to-sample correlation 

      Martín Alemany, Francisco; D'Addio, Salvatore; Camps Carmona, Adriano José; Martín Neira, Manuel (2014-05-01)
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      Accés restringit per política de l'editorial
      The exploitation of global navigation satellite systems Earth-reflected signals to perform ocean mesoscale altimetry from space has been originally proposed at the beginning of the 1990s. This technique is generally defined as

    • New methodology for the Faraday rotation angle retrieval in the SMOS field of view 

      Rubino, Roselena; Duffo Ubeda, Núria; González Gambau, Verónica; Torres Torres, Francisco; Corbella Sanahuja, Ignasi; Martín Neira, Manuel (Institute of Electrical and Electronics Engineers (IEEE), 2018)
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      In this work, a new methodology to estimate the Faraday Rotation Angle (FRA) from SMOS full-pol brightness temperature is presented. This approach is focused on retrieving the Vertical Total Electron Content (VTEC) and ...

    • Ocean salinity observations with SMOS mission 

      Martín Neira, Manuel; Font Capafons, Josep; Srokerz, M; Corbella Sanahuja, Ignasi; Camps Carmona, Adriano José (IEEE Piscataway, 2000)
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      The purpose of this paper is to present the capabilities of SMOS (Soil Moisture and Ocean Salinity mission) for the global mapping of ocean salinity from space. SMOS has been selected by the European Space Agency as the ...

    • On-ground characterization of the SMOS payload 

      Corbella Sanahuja, Ignasi; Torres Torres, Francisco; Duffo Ubeda, Núria; Martín Neira, Manuel; González Gambau, Veronica; Camps Carmona, Adriano José; Vall-Llossera Ferran, Mercedes Magdalena (IEEE Press. Institute of Electrical and Electronics Engineers, 2009-09)
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      The on-ground characterization of the synthetic aperture radiometer onboard the Soil Moisture and Ocean Salinity mission is described. Characterization includes basic functionality, internal calibration, thermal cycling, ...

    • One-point microwave radiometer calibration 

      Corbella Sanahuja, Ignasi; Torres Torres, Francisco; Closa Soteras, Josep; Duffo Ubeda, Núria; Durán Martínez, Israel; González Gambau, Verónica; Martín Neira, Manuel (2020-03-01)
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      A method for internally calibrating microwave total power radiometers by using only one level of noise injection is presented. It is based on having a previous accurate characterization of the receiver noise temperature, ...

    • Optimization and performance analysis of interferometric GNSS-R altimeters: application to the PARIS IoD mission 

      Camps Carmona, Adriano José; Hyuk, Park; Valencia Domènech, Enric; Pascual Biosca, Daniel; Martín Alemany, Francisco; Rius Jordán, Antonio; Ribó Vedrilla, Serni; Benito, Javier; Andres-Beivide, Ana; Saameno, Paula; Staton, Gavin; Martín Neira, Manuel; D'Addio, Salvatore; Willemsen, Philip (2014-05-01)
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      Accés restringit per política de l'editorial
      Reflectometry using Global Navigation Satellite System's signals (GNSS-R) of opportunity was originally conceived in the early 1990 s for mesoscale altimetry, and since then, many studies have shown its applicability to ...