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A new algebraic solution for transforming Cartesian to geodetic coordinates / Jia-Chun Guo in Survey review, vol 55 n° 389 (March 2023)  

Public [article]  inSurvey review > vol 55 n° 389 (March 2023) . - pp 169 - 177 Titre : A new algebraic solution for transforming Cartesian to geodetic coordinates Type de document : Article/Communication Auteurs : Jia-Chun Guo, Auteur ; Wenbin Shen, Auteur Année de publication : 2023 Article en page(s) : pp 169 - 177 Note générale : bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Systèmes de référence et réseaux [Termes IGN] calcul algébrique [Termes IGN] coordonnées cartésiennes [Termes IGN] coordonnées géodésiques [Termes IGN] système de coordonnées [Termes IGN] transformation de coordonnées Résumé : (auteur) An exact and stable algebraic solution based on solving a quartic equation with respect to the cosine function of the reduced latitude is proposed to transform Cartesian into geodetic coordinates. The unique proper root of the equation appropriate to the transformation is chosen from all possible roots by rigorous analyses and the singular region of the transformation that in which there at least one component of the geodetic coordinates is indeterminate or non-single-valued characteristics are determined strictly. The new algorithm does not need any approximation and the instability problems incurred in other algebraic solutions are overcome. For practical applications, the algorithm performs comparably to that of [Vermeille, H., 2011. An analytical method to transform geocentric into geodetic coordinates. Journal of geodesy, 85 (2), 105–117.] and shows a certain superiority in the singular disc over Vermeille's algorithm. Numéro de notice : A2023-135 Affiliation des auteurs : non IGN Thématique : POSITIONNEMENT Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.1080/00396265.2022.2071055 Date de publication en ligne : 24/05/2022 En ligne : https://doi.org/10.1080/00396265.2022.2071055 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=102686 [article]

Using converted WW1 Army Grid Referencing Systems to identify locations where Australian soldiers fell Europe / Rodney Deakin in International journal of cartography, vol 8 n° 3 (November 2022)  

Public [article]  inInternational journal of cartography > vol 8 n° 3 (November 2022) . - pp 308 - 325 Titre : Using converted WW1 Army Grid Referencing Systems to identify locations where Australian soldiers fell Europe Type de document : Article/Communication Auteurs : Rodney Deakin, Auteur Année de publication : 2022 Article en page(s) : pp 308 - 325 Note générale : bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Projections [Termes IGN] Australie [Termes IGN] carte ancienne [Termes IGN] carte militaire [Termes IGN] carte topographique [Termes IGN] coordonnées géographiques [Termes IGN] Europe (géographie politique) [Termes IGN] Google Maps [Termes IGN] grille [Termes IGN] guerre [Termes IGN] projection conforme [Termes IGN] projection Universal Transverse Mercator [Termes IGN] transformation de coordonnées [Termes IGN] vingtième siècle Résumé : (auteur) Topographic maps (1:40,000) used by the British Army on the Western Front in World War 1 had a five-part Grid Reference System consisting of: (1) Map Number; (2) Letter-Square – 24 letter squaresA to X on each map; (3) Number-Square – 36 (and sometimes 30) 1000-yard squares in each letter square; (4) Minor-Square – four 500-yard squares denoted a, b, c, d in each number square; (5) Small-Square – 10 × 10 = 100 small-squares in a minor-square. Letter and number grid Woesten references (e.g. X: 28.A.6.b.73) cannot be used by modern GPS navigation devices that require geographical coordinates (latitude and longitude) or current map grid coordinates. This paper provides the background behind this project and demonstrates a method of transforming WW1 grid references to Universal Transverse Mercator (UTM) grid coordinates using Google Maps to obtain geographical coordinates, Geographic to UTM grid conversion and a 2D Conformal transformation. As well, it provides a ‘snapshot’ of practical methods that were used to develop a software package that would allow amateur military historians to convert the WW1 Grid Reference System to contemporary coordinates. Numéro de notice : A2022-748 Affiliation des auteurs : non IGN Thématique : GEOMATIQUE Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.1080/23729333.2021.1877890 Date de publication en ligne : 13/05/2021 En ligne : https://doi.org/10.1080/23729333.2021.1877890 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=101734 [article]

Comparing Landsat-8 and Sentinel-2 top of atmosphere and surface reflectance in high latitude regions: case study in Alaska / Jiang Chen in Geocarto international, vol 37 n° 20 ([20/09/2022])  

Public [article]  inGeocarto international > vol 37 n° 20 [20/09/2022] . - pp 6052 - 6071 Titre : Comparing Landsat-8 and Sentinel-2 top of atmosphere and surface reflectance in high latitude regions: case study in Alaska Type de document : Article/Communication Auteurs : Jiang Chen, Auteur ; Weining Zhu, Auteur Année de publication : 2022 Article en page(s) : pp 6052 - 6071 Note générale : bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Traitement d'image optique [Termes IGN] Alaska (Etats-Unis) [Termes IGN] analyse comparative [Termes IGN] Google Earth Engine [Termes IGN] image Landsat-8 [Termes IGN] image proche infrarouge [Termes IGN] image Sentinel-MSI [Termes IGN] latitude [Termes IGN] Normalized Difference Vegetation Index [Termes IGN] observation de la Terre [Termes IGN] réflectance de surface Résumé : (auteur) Combining Landsat-8 and Sentinel-2 images is an effective approach to obtain high spatiotemporal resolution data for Earth observation and remote sensing modeling. The differences between Landsat-8 and Sentinel-2 products, such as the reflectance at the top of atmosphere (TOA) and land surface, should be compared and evaluated to make sure they are spectrally consistent. Their consistency has been evaluated and the differences have been empirically corrected at mid-low latitudes, but in high latitude areas with a higher solar zenith angle (SZA), the similar work has not been explored. In this study, Landsat-8 and Sentinel-2 TOA and surface reflectance in Alaska as well as some surface parameters, such as the normalized difference vegetation index (NDVI) and normalized difference snow index (NDSI), were compared using the massive data distributed on Google earth engine (GEE) online platform, and their consistency was evaluated and the uncertainty was analyzed. Some empirical models were suggested to convert Sentinel-2 products to be consistent with Landsat-8 products at all bands. The results show that TOA reflectance is more consistent than surface reflectance in Alaska. This study suggests that the consistency between Landsat-8 and Sentinel-2 at high latitudes should be paid more attention because their consistency is lower than that at mid-low latitudes. Numéro de notice : A2022-717 Affiliation des auteurs : non IGN Thématique : IMAGERIE Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : https://doi.org/10.1080/10106049.2021.1924295 Date de publication en ligne : 17/05/2021 En ligne : https://doi.org/10.1080/10106049.2021.1924295 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=101642 [article]

Estimation of swell height using spaceborne GNSS-R data from eight CYGNSS satellites / Yanli Zheng in Remote sensing, vol 14 n° 18 (September-2 2022)  

Public [article]  inRemote sensing > vol 14 n° 18 (September-2 2022) . - n° 4640 Titre : Estimation of swell height using spaceborne GNSS-R data from eight CYGNSS satellites Type de document : Article/Communication Auteurs : Yanli Zheng, Auteur ; Fu Zheng, Auteur ; Cheng Yang, Auteur ; et al., Auteur Année de publication : 2022 Article en page(s) : n° 4640 Note générale : bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Géodésie spatiale [Termes IGN] données GLONASS [Termes IGN] données GPS [Termes IGN] double différence [Termes IGN] latitude [Termes IGN] positionnement ponctuel précis [Termes IGN] positionnement statique [Termes IGN] retard troposphérique zénithal [Termes IGN] temps de convergence Résumé : (auteur) The orbital inclination angle of the GLONASS constellation is about 10° larger than that of GPS, Galileo, and BDS. Theoretically, the higher orbital inclination angle could provide better observation geometry in high latitude regions. A wealth of research has investigated the positioning accuracy of GLONASS and its impact on multi-GNSS, but rarely considered the contribution of the GLONASS constellation’s large orbit inclination angle. The performance of GLONASS in different latitude regions is evaluated in both stand-alone mode and integration with GPS in this paper. The performance of GPS is also presented for comparison. Three international GNSS service (IGS) networks located in high, middle, and low latitudes are selected for the current study. Multi-GNSS data between January 2021 and June 2021 are used for the assessment. The data quality check shows that the GLONASS data integrity is significantly lower than that of GPS. The constellation visibility analysis indicates that GLONASS has a much better elevation distribution than GPS in high latitude regions. Both daily double-difference network solutions and daily static Precise Point Positioning (PPP) solutions are evaluated. The statistical analysis of coordinate estimates indicates that, in high latitude regions, GLONASS has a comparable or even better accuracy than that of GPS, and GPS+GLONASS presents the best estimate accuracy; in middle latitude regions, GPS stand-alone constellation provides the best positioning accuracy; in low latitude regions, GLONASS offers the worst accuracy, but the positioning accuracy of GPS+GLONASS is better than that of GPS. The tropospheric estimates of GLONASS do not present a resemblance regional advantage as coordinate estimates, which is worse than that of GPS in all three networks. The PPP processing with combined GPS and GLONASS observations reduces the convergence time and improves the accuracy of tropospheric estimates in all three networks. Numéro de notice : A2022-770 Affiliation des auteurs : non IGN Thématique : POSITIONNEMENT Nature : Article DOI : 10.3390/rs14184640 Date de publication en ligne : 16/09/2022 En ligne : https://doi.org/10.3390/rs14184640 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=101796 [article]

Accuracy of GNSS RTK/NRTK height difference measurement / Robert Krzyzek in Applied geomatics, vol 14 n° 3 (September 2022)  

Public [article]  inApplied geomatics > vol 14 n° 3 (September 2022) . - pp 491 - 499 Titre : Accuracy of GNSS RTK/NRTK height difference measurement Type de document : Article/Communication Auteurs : Robert Krzyzek, Auteur ; Jacek Kudrys, Auteur Année de publication : 2022 Article en page(s) : pp 491 - 499 Note générale : bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Géodésie spatiale [Termes IGN] hauteur ellipsoïdale [Termes IGN] positionnement cinématique en temps réel [Termes IGN] positionnement par GNSS [Termes IGN] précision du positionnement Résumé : (auteur) The absolute error of ellipsoidal heights that may be achieved from Real-Time Kinematic/Network Real-Time Kinematic Global Navigation Satellite Systems (RTK/NRTK GNSS) measurements varies between 3 and 5 cm. Although the vertical root mean square (RMS) error reported by receivers generally has smaller values, it can only be treated as a measure of the precision of the obtained results. Nowadays, real-time GNSS measurements are commonly used to implement surveys with increased accuracy. In some cases, it may be of concern to determine the height difference with real-time techniques than the height itself. The use of height difference may be applicable when a point with a known height is available. This offers the possibility of transferring the known height to a distant point using GNSS technology instead of geometric leveling, which is more labor-intensive. The aim of the study was to verify if achieving accuracy better than 2 cm in ellipsoidal height difference using RTK/NRTK GNSS is possible, providing special conditions of measurement. In this paper, the results of research consisting of RTK/NRTK measurement of specific points with fixed heights in various terrain conditions are presented. A single GNSS reference station was used as a base station to determine ellipsoidal height in RTK mode and Ground-Based Augmentation System (GBAS) for measurements in NRTK mode. Comparison of the ellipsoidal height difference to the results of precise leveling allows us to determine ellipsoidal height measurement errors. The measurements were carried out in open terrain, with the covered horizon (under trees) and in urbanized areas (high buildings). The method proposed by the authors in this paper does not require knowledge of the quasi-geoid model, neither normal correction to obtain measurement results. Numéro de notice : A2022-618 Affiliation des auteurs : non IGN Thématique : POSITIONNEMENT Nature : Article DOI : 10.1007/s12518-022-00450-2 En ligne : https://doi.org/10.1007/s12518-022-00450-2 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=101378 [article]

The RTM harmonic correction revisited / R. Klees in Journal of geodesy, vol 96 n° 6 (June 2022)  

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Challenges related to the determination of altitudes of mountain peaks presented on cartographic sources / Katarzyna Chwedczuk in Geodetski vestnik, vol 66 n° 1 (March 2022)  

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A parameterization of the cloud scattering polarization signal derived from GPM observations for microwave fast radative transfer models / Victoria Sol Galligani in IEEE Transactions on geoscience and remote sensing, vol 59 n° 11 (November 2021)  

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La nouvelle grille de conversion altimétrique RAF18b / François L'écu in XYZ, n° 167 (juin 2021)

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Validating geoid models with marine GNSS measurements, sea surface models, and additional gravity observations in the Gulf of Finland / Timo Saari in Marine geodesy, vol 44 n° 3 (May 2021)  

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A geographic information-driven method and a new large scale dataset for remote sensing cloud/snow detection / Xi Wu in ISPRS Journal of photogrammetry and remote sensing, vol 174 (April 2021)  

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Strategy for the realisation of the International Height Reference System (IHRS) / Laura Sánchez in Journal of geodesy, vol 95 n° 4 (April 2021)  

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Mitigating high latitude ionospheric scintillation effects on GNSS Precise Point Positioning exploiting 1-s scintillation indices / Kai Guo in Journal of geodesy, vol 95 n° 3 (March 2021)  

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Descriptif technique du quasi-géoïde gravimétrique QGF16 et de la surface de conversion altimétrique RAF18b / François L'écu (2021)

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A local projection for integrating geodetic and terrestrial coordinate systems / Mike Bremmer in Survey review, vol 52 n° 374 (August 2020)  

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