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Recovery of cadastral boundaries with GNSS equipment / A. Cina in Survey review, vol 48 n° 350 (September 2016)
[article]
Titre : Recovery of cadastral boundaries with GNSS equipment Type de document : Article/Communication Auteurs : A. Cina, Auteur ; A. M. Manzino, Auteur ; G. Manzino, Auteur Année de publication : 2016 Article en page(s) : pp 338 - 346 Note générale : bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Cadastre étranger
[Termes IGN] appariement de données localisées
[Termes IGN] cadastre ancien
[Termes IGN] cadastre numérique
[Termes IGN] ellipsoïde de Bessel
[Termes IGN] Italie
[Termes IGN] limite cadastrale
[Termes IGN] numérisation du cadastre
[Termes IGN] positionnement par GNSS
[Termes IGN] projection
[Termes IGN] système de référence localRésumé : (auteur) The purpose of this work is to propose a new redefinition of cadastral boundaries using GNSS equipment and cadastral maps. These maps are the ‘original’ maps of the Italian Land Cadastre, the first cartographic support built directly from measures carried out by technicians during implantation of the Italian land cadastre. They are called ‘originali di impianto’ – ‘originals of implantation’ or ‘implant maps’. As such, these maps are valuable and are kept with great care. Recently, the Italian cadastre has carried out an accurate digitisation of these maps in a raster format at a high resolution. In this work, the authors propose the use of these digital maps for the recovery of cadastral boundary. The original cadastral map, one of the primary sources relied upon in defining legal boundaries, generally uses the Bessel ellipsoid localised in Genova and the Cassini-Soldner projection; the GNSS equipment, on the other hand, uses the geocentric ellipsoid with global or continental realisations. After an RTK positioning, the receivers usually provide the cartographic coordinates in a Gauss projection. However, our study deals with the problem of using different projections and reference systems within the limits of a map. In this context, the transition between systems and projections can be made through a conformal transformation with deformations slighter than graphical errors in the map. The difficulty of finding identifiable points in both reference systems is partially solved through a new way of carrying out the redefinition of boundaries by exploiting geometric information. Numéro de notice : A2016-641 Affiliation des auteurs : non IGN Thématique : GEOMATIQUE/POSITIONNEMENT Nature : Article DOI : 10.1179/1752270615Y.0000000007 En ligne : https://doi.org/10.1179/1752270615Y.0000000007 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=81846
in Survey review > vol 48 n° 350 (September 2016) . - pp 338 - 346[article]A remark on the GNSS single difference model with common clock scheme for attitude determination / Wantong Chen in Journal of applied geodesy, vol 10 n° 3 (September 2016)
[article]
Titre : A remark on the GNSS single difference model with common clock scheme for attitude determination Type de document : Article/Communication Auteurs : Wantong Chen, Auteur Année de publication : 2016 Article en page(s) : pp 167 – 173 Note générale : bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Navigation et positionnement
[Termes IGN] antenne GNSS
[Termes IGN] erreur de phase
[Termes IGN] erreur systématique
[Termes IGN] horloge
[Termes IGN] orientation du capteur
[Termes IGN] phase GNSS
[Termes IGN] simple différenceRésumé : (auteur) GNSS-based attitude determination technique is an important field of study, in which two schemes can be used to construct the actual system: the common clock scheme and the non-common clock scheme. Compared with the non-common clock scheme, the common clock scheme can strongly improve both the reliability and the accuracy. However, in order to gain these advantages, specific care must be taken in the implementation. The cares are thus discussed, based on the generating technique of carrier phase measurement in GNSS receivers. A qualitative assessment of potential phase bias contributes is also carried out. Possible technical difficulties are pointed out for the development of single-board multi-antenna GNSS attitude systems with a common clock. Numéro de notice : A2016-970 Affiliation des auteurs : non IGN Thématique : POSITIONNEMENT Nature : Article DOI : 10.1515/jag-2016-0008 En ligne : https://doi.org/10.1515/jag-2016-0008 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=83677
in Journal of applied geodesy > vol 10 n° 3 (September 2016) . - pp 167 – 173[article]Taking correlations in GPS least squares adjustments into account with a diagonal covariance matrix / Gaël Kermarrec in Journal of geodesy, vol 90 n° 9 (September 2016)
[article]
Titre : Taking correlations in GPS least squares adjustments into account with a diagonal covariance matrix Type de document : Article/Communication Auteurs : Gaël Kermarrec, Auteur ; Steffen Schön, Auteur Année de publication : 2016 Article en page(s) : pp 793 – 805 Note générale : bibliographie Langues : Anglais (eng) Descripteur : [Termes IGN] compensation par moindres carrés
[Termes IGN] corrélation
[Termes IGN] données GPS
[Termes IGN] estimateur
[Termes IGN] matrice de covariance
[Termes IGN] matrice diagonale
[Termes IGN] pondération
[Termes IGN] positionnement différentiel
[Termes IGN] positionnement par GPS
[Termes IGN] régression
[Termes IGN] série temporelle
[Vedettes matières IGN] Traitement de données GNSSRésumé : (auteur) Based on the results of Luati and Proietti (Ann Inst Stat Math 63:673–686, 2011) on an equivalence for a certain class of polynomial regressions between the diagonally weighted least squares (DWLS) and the generalized least squares (GLS) estimator, an alternative way to take correlations into account thanks to a diagonal covariance matrix is presented. The equivalent covariance matrix is much easier to compute than a diagonalization of the covariance matrix via eigenvalue decomposition which also implies a change of the least squares equations. This condensed matrix, for use in the least squares adjustment, can be seen as a diagonal or reduced version of the original matrix, its elements being simply the sums of the rows elements of the weighting matrix. The least squares results obtained with the equivalent diagonal matrices and those given by the fully populated covariance matrix are mathematically strictly equivalent for the mean estimator in terms of estimate and its a priori cofactor matrix. It is shown that this equivalence can be empirically extended to further classes of design matrices such as those used in GPS positioning (single point positioning, precise point positioning or relative positioning with double differences). Applying this new model to simulated time series of correlated observations, a significant reduction of the coordinate differences compared with the solutions computed with the commonly used diagonal elevation-dependent model was reached for the GPS relative positioning with double differences, single point positioning as well as precise point positioning cases. The estimate differences between the equivalent and classical model with fully populated covariance matrix were below the mm for all simulated GPS cases and below the sub-mm for the relative positioning with double differences. These results were confirmed by analyzing real data. Consequently, the equivalent diagonal covariance matrices, compared with the often used elevation-dependent diagonal covariance matrix is appropriate to take correlations in GPS least squares adjustment into account, yielding more accurate cofactor matrices of the unknown. Numéro de notice : A2016-654 Affiliation des auteurs : non IGN Thématique : MATHEMATIQUE/POSITIONNEMENT Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.1007/s00190-016-0911-z En ligne : http://dx.doi.org/10.1007/s00190-016-0911-z Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=81856
in Journal of geodesy > vol 90 n° 9 (September 2016) . - pp 793 – 805[article]Variance components estimation of residual errors in GPS precise positioning / Darko Anđić in Geodetski vestnik, vol 60 n° 3 (September - November 2016)
[article]
Titre : Variance components estimation of residual errors in GPS precise positioning Type de document : Article/Communication Auteurs : Darko Anđić, Auteur Année de publication : 2016 Article en page(s) : pp 467 - 482 Note générale : Bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Navigation et positionnement
[Termes IGN] analyse en composantes indépendantes
[Termes IGN] effet atmosphérique
[Termes IGN] positionnement différentiel
[Termes IGN] positionnement par GPS
[Termes IGN] précision du positionnement
[Termes IGN] propagation troposphérique
[Termes IGN] résiduRésumé : (Auteur) Variance components analysis of residual errors remaining in the GPS double-difference phase observations is presented in this paper. These errors arise due to unmodeled ionospheric, tropospheric and multipath effects and limit the accuracy of n (northwards), e (eastwards) and u (upwards) coordinate estimates. In addition, there are unavoidable pure random errors. An integral approach to variance components estimation of the residual errors is presented herein. The mathematical basis of the approach lies in the two-way nested classification, where one uses a linear model with random effects. It turned out that, for a baseline of 40km in length at mid-latitude region and during a year of the lowest sunspot activity in the 11-year cycle, daily standard deviations estimates of combined tropospheric and ionospheric effects are with intervals of ~1–11mm, ~1–7mm and ~4–51mm for n, e and u coordinate, respectively. In the same order, for the multipath effects, the intervals are ~4–12mm, ~3–9mm and ~8–30mm, while with pure random error those are ~5–9mm, ~4–7mm and ~9–20mm. It is important to say that the highest values arise in summer and the lowest in winter period. Numéro de notice : A2016--065 Affiliation des auteurs : non IGN Thématique : POSITIONNEMENT Nature : Article DOI : 10.15292/geodetski-vestnik.2016.03.467-482 En ligne : https://dx.doi.org/10.15292/geodetski-vestnik.2016.03.467-482 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=82293
in Geodetski vestnik > vol 60 n° 3 (September - November 2016) . - pp 467 - 482[article]Réservation
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Code-barres Cote Support Localisation Section Disponibilité 139-2016031 RAB Revue Centre de documentation En réserve L003 Disponible A new method to improve the performance of multi-GNSS pseudorange positioning in signal-degraded environment / Hui Liu in Advances in space research, vol 58 n° 4 (August 2016)
[article]
Titre : A new method to improve the performance of multi-GNSS pseudorange positioning in signal-degraded environment Type de document : Article/Communication Auteurs : Hui Liu, Auteur ; Longwei Xu, Auteur ; Bao Shu, Auteur ; et al., Auteur Année de publication : 2016 Article en page(s) : pp 577 - 586 Note générale : bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Géodésie spatiale
[Termes IGN] interopérabilité
[Termes IGN] mesurage de pseudo-distance
[Termes IGN] système de positionnement par satellites
[Termes IGN] visibilitéRésumé : (auteur) There are two existing multi-GNSS positioning methods, (1) separate receiver clock parameter is set for each constellation, (2) estimating intersystem biases (ISBs) in advance to obtain position solutions with only four unknowns. The former is the regular method and its unknowns include three receiver-coordinate parameters and several receiver clock parameters (depend on the number of participant constellations), so that it may disable when few satellites belonging to different GNSS are in view. The latter is one workable way to obtain position solution with only four visible satellites. In addition to the disabled regular method, the positioning results by the ISB-corrected method are often unsatisfactory for navigation users in signal-degraded environment. Both the deviation of ISB-solutions and the remaining measurement errors of the need corrected observations are factors to degrade location precision. Apart from these, fewer visible satellites usually cause a low robustness of the positioning model, which cause the negative influence of various errors is amplified. Based on the variation of various measurement errors, we propose a new ISSB-corrected method with observations corrected by corresponding satellite-dependent parameters. The new parameter contains the difference of time scales, hardware delays and uncorrected measurement errors between the corresponding satellite and reference, in other words, it can synthetically consider measurement errors and the ISB. By the ISSB-corrected method, we not only achieve positioning solutions with four satellites, but also significantly reduce the accuracy loss. Many experiments are conducted to present the superiority of the ISSB-corrected method. In open-area, the accuracies of regular and ISB-corrected methods are nearly equal. Apart from a similar accuracy in horizontal, the accuracy is improved by approximate 10% in up direction with respect to the two existing methods. Given the high redundancy of model in open-area, the new method may not improve the accuracy remarkably. However, it can make great contributions in signal-degraded environments. In order to compare the performance of ISB- and ISSB-corrected methods in environment with limited visible satellites, we simulate several scenarios (different satellites participant or various receivers) with only four participant satellites in the positioning solution. By the ISSB-corrected method, the 3D RMS of positioning results with four satellites is about 15 m, while it is usually worse than 25 m for the ISB-corrected method. In an urban vehicular test, the horizontal positioning error of the ISSB-corrected method is less than 20 m; and the ISB-corrected method may reach up to 70 m. Numéro de notice : A2016-592 Affiliation des auteurs : non IGN Thématique : POSITIONNEMENT Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.1016/j.asr.2016.05.016 En ligne : http://dx.doi.org/10.1016/j.asr.2016.05.016 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=81748
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