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Validation of a corner reflector installation at Côte d’Azur multi-technique geodetic observatory / Xavier Collilieux in Advances in space research, vol 70 n° 2 (15 July 2022)  

Public [article]  inAdvances in space research > vol 70 n° 2 (15 July 2022) . - pp 360 - 370 Titre : Validation of a corner reflector installation at Côte d’Azur multi-technique geodetic observatory Type de document : Article/Communication Auteurs : Xavier Collilieux , Auteur ; Clément Courde, Auteur ; Bénédicte Fruneau , Auteur ; Mourad Aimar, Auteur ; Guillaume Schmidt, Auteur ; Isabelle Delprat, Auteur ; Marie-Amélie Defresne, Auteur ; Damien Pesce, Auteur ; Fabien Bergerault, Auteur ; Guy Wöppelmann , Auteur Année de publication : 2022 Projets : Université de Paris / Clerici, Christine Article en page(s) : pp 360 - 370 Note générale : bibliographie This study contributes to the IdEx Université de Paris ANR-18-IDEX-0001. It was supported by the Programme National GRAM INSAROME of CNRS/INSU with INP and IN2P3 co-funded by CNES but also by BQR-OCA. Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Acquisition d'image(s) et de donnée(s) [Termes IGN] coin réflecteur [Termes IGN] constellation Sentinel [Termes IGN] Global Geodetic Observing System [Termes IGN] image radar moirée [Termes IGN] interféromètrie par radar à antenne synthétique [Termes IGN] observatoire astronomique Résumé : (auteur) We present the procedure we followed to design an artificial corner reflector (CR) at the Calern site of Côte d’Azur Observatory (France). Although still few in number, such reflectors are an integral part of the Global Geodetic Observing System (GGOS) infrastructure. They can be used as a stable radar target in SAR images to connect local InSAR deformation maps to the global Terrestrial Reference Frame and for SAR absolute determination. During a test phase, the orientation of the CR was changed in order to be aligned toward all possible orbits of Sentinel-1A/1B satellites. On the different SAR images, the CR exhibits a high backscattering signal, and provides a Signal-to-Clutter Ratio larger than 26 dB. Since December 2018, the CR is specifically oriented toward the relative orbit 88. It is clearly detected as a PS in our InSAR analyses and as expected, the standard deviation of displacement measured on the CR is lower than on surrounding PS. A first local survey was performed to locate precisely this CR with respect to the existing geodetic instruments and annual campaigns have been carried out since then to insure its stability over time. Numéro de notice : A2022-337 Affiliation des auteurs : ENSG+Ext (2020- ) Thématique : POSITIONNEMENT Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.1016/j.asr.2022.04.050 Date de publication en ligne : 29/04/2022 En ligne : https://doi.org/10.1016/j.asr.2022.04.050 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=100694 [article]

Inclusion of GPS clock estimates for satellites Sentinel-3A/3B in DORIS geodetic solutions / Petr Štěpánek in Journal of geodesy, vol 94 n° 12 (December 2020)  

Public [article]  inJournal of geodesy > vol 94 n° 12 (December 2020) . - n° 116 Titre : Inclusion of GPS clock estimates for satellites Sentinel-3A/3B in DORIS geodetic solutions Type de document : Article/Communication Auteurs : Petr Štěpánek, Auteur ; Duan Bingbing, Auteur ; Filler Vratislav, Auteur ; et al., Auteur Année de publication : 2020 Article en page(s) : n° 116 Note générale : bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Géodésie spatiale [Termes IGN] Atlantique Sud [Termes IGN] Cryosat [Termes IGN] décalage d'horloge [Termes IGN] données DORIS [Termes IGN] horloge du récepteur [Termes IGN] Jason [Termes IGN] oscillateur [Termes IGN] récepteur DORIS [Termes IGN] récepteur GPS [Termes IGN] rotation de la Terre [Termes IGN] SARAL [Termes IGN] Sentinel-3 Résumé : (auteur) A unique architecture of Sentinel-3A and Sentinel-3B satellites includes the shared ultra-stable oscillator (USO) by the DORIS and GPS receivers. This concept enables to apply onboard GPS clock estimates in the DORIS processing substituting the DORIS polynomial clock model by the GPS epoch-wise model, together with a DORIS-specific clock offset. Such an approach is particularly profitable for the mitigation of the South Atlantic Anomaly (SAA) effect affecting the short-term frequency stability of the USO oscillator in the South America and South Atlantic region. The GPS clock behavior precisely maps the SAA effect and enables us to demonstrate a difference of the USO sensitivity to the SAA for Sentinel-3A and Sentinel-3B. We present world grid maps of clock time derivatives for both Sentinels, displaying a different sign of the direct effect and other differences in the USO memory/recovery effect. Moreover, we present the impact of SAA on 3D positioning where the largest SAA-related bias reaches several centimeters. We also determine an effect of the precise clock modeling on the Earth rotation parameter estimates. In addition to these improvements, the elimination of the SAA effect gives us an opportunity to get an almost SAA-free DORIS solution from Sentinel-3A and Sentinel-3B satellites. Using the combined solution of both Sentinels as a reference, we estimate the SAA effect on the DORIS beacon positions also for satellites Jason-2, Jason-3, Saral, Cryosat-2 and Hy-2A and find significant positioning biases for all the recent satellites except Saral. Numéro de notice : A2020-737 Affiliation des auteurs : non IGN Thématique : POSITIONNEMENT Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.1007/s00190-020-01428-x Date de publication en ligne : 18/11/2020 En ligne : https://doi.org/10.1007/s00190-020-01428-x Format de la ressource électronique : url article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=96353 [article]

Troposphere delay modeling with horizontal gradients for satellite laser ranging / Mateusz Drożdżewski in Journal of geodesy, vol 93 n°10 (October 2019)  

Public [article]  inJournal of geodesy > vol 93 n°10 (October 2019) Titre : Troposphere delay modeling with horizontal gradients for satellite laser ranging Type de document : Article/Communication Auteurs : Mateusz Drożdżewski, Auteur ; Krzysztof Sosnica, Auteur ; Florian Zus, Auteur ; Kyriakos Balidakis, Auteur Année de publication : 2019 Note générale : bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Géodésie spatiale [Termes IGN] angle vertical [Termes IGN] coordonnées polaires [Termes IGN] dissymétrie [Termes IGN] erreur systématique [Termes IGN] géocentre [Termes IGN] gradient de troposphère [Termes IGN] interférométrie à très grande base [Termes IGN] Lageos [Termes IGN] retard troposphérique [Termes IGN] Sentinel-3 [Termes IGN] station TLS (télémétrie) [Termes IGN] télémètre laser sur satellite Résumé : (auteur) Satellite laser ranging (SLR) constitutes a fundamental space geodetic technique providing global geodetic parameters, such as geocenter coordinates, Earth rotation parameters, and low-degree gravity field coefficients. The tropospheric delay correction is one of the crucial corrections that have to be taken into account when processing SLR data. Current conventional models of the troposphere delays assume a full symmetry of the atmosphere above SLR stations. Neglecting horizontal gradients in SLR solutions introduces a systematic error in SLR products, especially for the observations at low elevation angles, and leads to a deterioration of the consistency between SLR and other space geodetic techniques, such as global navigational satellite systems and very-long-baseline interferometry. We derive new mapping function coefficients, as well as first- and second-order horizontal gradients, all of which are based on numerical weather models, in order to properly consider the azimuthal asymmetry in SLR solutions. We test the enhanced mapping function and horizontal gradients on the solutions based on 11 years of SLR observations to LAGEOS-1/2 satellites and 1 year of SLR observations to Sentinel-3A. The consideration of azimuthal asymmetry of the atmosphere above the SLR stations has a systematic effect on SLR-derived products, such as station and geocenter coordinates and pole coordinates. Horizontal gradients in SLR solutions improve the consistency between SLR-derived pole coordinates and the combined IERS-C04 series by means of reducing the offset for the X and Y pole coordinates by 20 μas. The second-order horizontal gradients are negligible in SLR solutions; thus, including first-order gradients is sufficient for SLR solutions. Numéro de notice : A2019-607 Affiliation des auteurs : non IGN Thématique : POSITIONNEMENT Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.1007/s00190-019-01287-1 Date de publication en ligne : 22/08/2019 En ligne : https://doi.org/10.1007/s00190-019-01287-1 Format de la ressource électronique : url article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=94790 [article]

Precise orbit determination of the Sentinel-3A altimetry satellite using ambiguity-fixed GPS carrier phase observations / Oliver Montenbruck in Journal of geodesy, vol 92 n° 7 (July 2018)  

Public [article]  inJournal of geodesy > vol 92 n° 7 (July 2018) . - pp 711 - 726 Titre : Precise orbit determination of the Sentinel-3A altimetry satellite using ambiguity-fixed GPS carrier phase observations Type de document : Article/Communication Auteurs : Oliver Montenbruck, Auteur ; Stefan Hackel, Auteur ; Adrian Jäggi, Auteur Année de publication : 2018 Article en page(s) : pp 711 - 726 Note générale : Bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Techniques orbitales [Termes IGN] données altimétriques [Termes IGN] double différence [Termes IGN] orbitographie [Termes IGN] phase [Termes IGN] Sentinel-3 Résumé : (Auteur) The Sentinel-3 mission takes routine measurements of sea surface heights and depends crucially on accurate and precise knowledge of the spacecraft. Orbit determination with a targeted uncertainty of less than 2 cm in radial direction is supported through an onboard Global Positioning System (GPS) receiver, a Doppler Orbitography and Radiopositioning Integrated by Satellite instrument, and a complementary laser retroreflector for satellite laser ranging. Within this study, the potential of ambiguity fixing for GPS-only precise orbit determination (POD) of the Sentinel-3 spacecraft is assessed. A refined strategy for carrier phase generation out of low-level measurements is employed to cope with half-cycle ambiguities in the tracking of the Sentinel-3 GPS receiver that have so far inhibited ambiguity-fixed POD solutions. Rather than explicitly fixing double-difference phase ambiguities with respect to a network of terrestrial reference stations, a single-receiver ambiguity resolution concept is employed that builds on dedicated GPS orbit, clock, and wide-lane bias products provided by the CNES/CLS (Centre National d’Études Spatiales/Collecte Localisation Satellites) analysis center of the International GNSS Service. Compared to float ambiguity solutions, a notably improved precision can be inferred from laser ranging residuals. These decrease from roughly 9 mm down to 5 mm standard deviation for high-grade stations on average over low and high elevations. Furthermore, the ambiguity-fixed orbits offer a substantially improved cross-track accuracy and help to identify lateral offsets in the GPS antenna or center-of-mass (CoM) location. With respect to altimetry, the improved orbit precision also benefits the global consistency of sea surface measurements. However, modeling of the absolute height continues to rely on proper dynamical models for the spacecraft motion as well as ground calibrations for the relative position of the altimeter reference point and the CoM. Numéro de notice : A2018-453 Affiliation des auteurs : non IGN Thématique : POSITIONNEMENT Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.1007/s00190-017-1090-2 Date de publication en ligne : 27/11/2017 En ligne : https://doi.org/10.1007/s00190-017-1090-2 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=91044 [article]

InSAR data for geohazard assessment in UNESCO World Heritage sites: state-of-the-art and perspectives in the Copernicus era / Deodato Tapete in International journal of applied Earth observation and geoinformation, vol 63 (December 2017)  

Public [article]  inInternational journal of applied Earth observation and geoinformation > vol 63 (December 2017) . - pp 24 - 32 Titre : InSAR data for geohazard assessment in UNESCO World Heritage sites: state-of-the-art and perspectives in the Copernicus era Type de document : Article/Communication Auteurs : Deodato Tapete, Auteur ; Francesca Cigna, Auteur Année de publication : 2017 Article en page(s) : pp 24 - 32 Note générale : bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Applications de télédétection [Termes IGN] coin réflecteur [Termes IGN] constellation Sentinel [Termes IGN] Copernicus (programme européen) [Termes IGN] Europe (géographie politique) [Termes IGN] image radar moirée [Termes IGN] interferométrie différentielle [Termes IGN] interféromètrie par radar à antenne synthétique [Termes IGN] patrimoine culturel [Termes IGN] patrimoine immobilier [Termes IGN] risque naturel [Termes IGN] Russie [Termes IGN] surveillance géologique Résumé : (auteur) Protection of natural and cultural heritage is encompassed by the United Nations’ 2030 Agenda for Sustainable Development and is among the innovative applications and services of the European Union’s Earth Observation programme Copernicus. We are currently witnessing an increasing exploitation of Interferometric Synthetic Aperture Radar (InSAR) methods to assess geohazards affecting cultural heritage. This paper offers the first data mining exercise to identify InSAR geoinformation that is digitally available and/or published and that spatially includes one or more cultural, natural and mixed UNESCO World Heritage Site (WHS). The exercise focused on the 45 countries of geographical Europe, Turkey, Israel and the Russian Federation, and their 445 WHS of Outstanding Universal Value. We built a database of academic and grey literature collated via a Boolean search of the ISI Web of Science catalogue and systematic skim-reading to a total number of 280 publications as of the end of 2016. Over 460 InSAR open access digital datasets were also analysed. We found clusters of WHS covered by InSAR data in Italy, the Netherlands, western Germany, eastern Spain, Greece and the UK that match with the geographic distribution of InSAR expertise and geohazard hotspots. The existing stock of InSAR geoinformation already provides an overall WHS coverage of 36%, with similar proportion of available data for ‘urban’ (40%) and ‘rural’ (34%) WHS. The sites with the highest number of publications are historic city centres (e.g. Amsterdam, Athens, Barcelona, Lisbon, Paris, Rome), as well as Permanent Geohazard Supersites (e.g. Mt. Etna, Naples, Istanbul), where the impact of natural and/or anthropogenic processes is well known. First generation SAR data (mainly ERS-1/2) predominate in the literature with over 15 new publications/year since 2002, whilst second and third generation data show less pronounced rates since 2007 and 2014, respectively. The current engagement level of end-users appears still limited (less than 1% of publications involve heritage stakeholders), and a shared guidance on the use of InSAR for heritage practitioners does not exist yet. Towards the development of Copernicus’ services and applications in support of cultural heritage preservation and management, our analysis contributes to: outline the existing capabilities; focus on requirements for bespoke InSAR-derived products and services; and consider possible implementation scenarios both in emergency and ordinary circumstances. Numéro de notice : A2017-412 Affiliation des auteurs : non IGN Thématique : IMAGERIE Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.1016/j.jag.2017.07.007 En ligne : https://doi.org/10.1016/j.jag.2017.07.007 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=86299 [article]

Examination of Sentinel-2A multi-spectral instrument (MSI) reflectance anisotropy and the suitability of a general method to normalize MSI reflectance to nadir BRDF adjusted reflectance / David P. Roy in Remote sensing of environment, vol 199 (15 September 2017)  

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Copernicus Sentinel-2A calibration and products validation status / Ferran Gascon in Remote sensing, vol 9 n° 6 (June 2017)  

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Baltic sea ice concentration estimation using SENTINEL-1 SAR and AMSR2 microwave radiometer data / Juha Karvonen in IEEE Transactions on geoscience and remote sensing, vol 55 n° 5 (May 2017)  

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Journée Copernicus / Anonyme in Géomatique expert, n° 116 (mai - juin 2017)

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Sentinel-1 interferometric SAR mapping of precipitable water vapor over a country-spanning area / Pedro Mateus in IEEE Transactions on geoscience and remote sensing, vol 55 n° 5 (May 2017)  

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2nd workshop Preparation for the Sentinel-2 in Europe, Oslo, 11-12 October 2016 / Arnt Kristian Gjertsen (2016)  

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Examining the potential of Sentinel-2 MSI spectral resolution in quantifying above ground biomass across different fertilizer treatments / Mbulisi Sibanda in ISPRS Journal of photogrammetry and remote sensing, vol 110 (December 2015)  

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Les instruments optiques d'observation de la Terre / Georges Otrio (2015)

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Sentinel-1, the radar mission for GMES operational land and sea services / E. Attema in ESA bulletin, n° 131 (August 2007)  

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Sentinel-2, the optical high-resolution mission for GMES operational services / P. Martimort in ESA bulletin, n° 131 (August 2007)  

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