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Assessment of along-normal uncertainties for application to terrestrial laser scanning surveys of engineering structures / Tarvo Mill in Survey review, vol 51 n° 364 (January 2019)  

Public [article]  inSurvey review > vol 51 n° 364 (January 2019) . - pp 1 - 16 Titre : Assessment of along-normal uncertainties for application to terrestrial laser scanning surveys of engineering structures Type de document : Article/Communication Auteurs : Tarvo Mill, Auteur ; Artu Ellmann, Auteur Année de publication : 2019 Article en page(s) : pp 1 - 16 Note générale : Bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Lasergrammétrie [Termes descripteurs IGN] bruit (théorie du signal) [Termes descripteurs IGN] génie civil [Termes descripteurs IGN] incertitude des données [Termes descripteurs IGN] optimisation (mathématiques) [Termes descripteurs IGN] télémétrie laser terrestre Résumé : (Auteur) A method for estimating the range and spatial distribution of terrestrial laser scanning uncertainties occurring during the survey of engineering structures is presented and numerically verified. The emphasis is on the assessment of along-normal uncertainties of the surface to be surveyed. To investigate the behaviour of such uncertainties, various surveying scenarios are simulated and studied. Theoretical derivations are numerically verified, and these results are compared with those of previous empirical studies. The influence of along-normal noise on geometric modelling of surveyed surfaces is studied. In addition, suggestions are provided for how to optimising scanning locations, yielding the reduced ANU. Numéro de notice : A2019-169 Thématique : IMAGERIE Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.1080/00396265.2017.1361565 date de publication en ligne : 10/08/2017 En ligne : https://doi.org/10.1080/00396265.2017.1361565 Format de la ressource électronique : URL Article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=92616 [article]

Regional geoid computation by least squares modified Hotine’s formula with additive corrections / Silja Märdla in Journal of geodesy, vol 92 n° 3 (March 2018)  

Public [article]  inJournal of geodesy > vol 92 n° 3 (March 2018) . - pp 253 - 270 Titre : Regional geoid computation by least squares modified Hotine’s formula with additive corrections Type de document : Article/Communication Auteurs : Silja Märdla, Auteur ; Artu Ellmann, Auteur ; Jonas Ågren, Auteur ; Lard Erik Sjöberg, Auteur Année de publication : 2018 Article en page(s) : pp 253 - 270 Note générale : Bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Géodésie physique [Termes descripteurs IGN] anomalie de pesanteur [Termes descripteurs IGN] formule de Stokes [Termes descripteurs IGN] géoïde local [Termes descripteurs IGN] méthode des moindres carrés [Termes descripteurs IGN] quasi-géoïde Résumé : (Auteur) Geoid and quasigeoid modelling from gravity anomalies by the method of least squares modification of Stokes’s formula with additive corrections is adapted for the usage with gravity disturbances and Hotine’s formula. The biased, unbiased and optimum versions of least squares modification are considered. Equations are presented for the four additive corrections that account for the combined (direct plus indirect) effect of downward continuation (DWC), topographic, atmospheric and ellipsoidal corrections in geoid or quasigeoid modelling. The geoid or quasigeoid modelling scheme by the least squares modified Hotine formula is numerically verified, analysed and compared to the Stokes counterpart in a heterogeneous study area. The resulting geoid models and the additive corrections computed both for use with Stokes’s or Hotine’s formula differ most in high topography areas. Over the study area (reaching almost 2 km in altitude), the approximate geoid models (before the additive corrections) differ by 7 mm on average with a 3 mm standard deviation (SD) and a maximum of 1.3 cm. The additive corrections, out of which only the DWC correction has a numerically significant difference, improve the agreement between respective geoid or quasigeoid models to an average difference of 5 mm with a 1 mm SD and a maximum of 8 mm. Numéro de notice : A2018-060 Thématique : POSITIONNEMENT Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.1007/s00190-017-1061-7 En ligne : https://doi.org/10.1007/s00190-017-1061-7 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=89393 [article]