Centre dedocumentation
scientifique

GNSS best integer equivariant estimation combining with integer least squares estimation: an integrated ambiguity resolution method with optimal integer aperture test / Liye Ma in GPS solutions, vol 26 n° 4 (October 2022)  

Public [article]  inGPS solutions > vol 26 n° 4 (October 2022) . - n° 100 Titre : GNSS best integer equivariant estimation combining with integer least squares estimation: an integrated ambiguity resolution method with optimal integer aperture test Type de document : Article/Communication Auteurs : Liye Ma, Auteur ; Yidong Lou, Auteur ; Liguo Lu, Auteur ; et al., Auteur Année de publication : 2022 Article en page(s) : n° 100 Note générale : bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Géodésie spatiale [Termes IGN] méthode des moindres carrés [Termes IGN] phase GNSS [Termes IGN] positionnement par GNSS [Termes IGN] précision du positionnement [Termes IGN] résolution d'ambiguïté Résumé : (auteur) Accurate and reliable carrier phase ambiguity resolution (AR) is the key to global navigation satellite system (GNSS) high-precision navigation and positioning applications. The integer least squares (ILS) estimation and the best integer equivariant (BIE) estimation are two widely used AR method, with the former considered to have the highest success rate and the latter to be optimal in the minimum mean squared error (MSE) sense. We analyzed three key issues of applying the BIE method in detail, including the use boundary of BIE, the number of candidates to be involved, and the weight determination among ambiguity candidates. It has been demonstrated that the BIE estimator is superior to ILS estimator from an overall perspective, but not always the best in each specific epoch. Therefore, we recommend constructing an integrated ambiguity resolution scheme that combines BIE with ILS, and we propose to adopt the optimal integer aperture (OIA) test as a criterion to distinguish the two. Moreover, a new criterion referred to the OIA test is proposed to determine the number of candidates involved in the BIE estimator. We also attempt to add the quadratic forms of baseline residuals into the weight function of BIE, aiming to reach a more accurate estimator. Finally, an integrated AR method that combines ILS with BIE and distinguished by the OIA test is proposed, named OIA-BIE. A set of real-measured vehicle data are tested to evaluate its performance, compared to least squares (LS), ILS, and the original BIE. The results show that the positioning accuracy of OIA-BIE is a little better than BIE, better than ILS, and significantly better than LS. Moreover, the average time consumption of ILS, BIE, and OIA-BIE are also evaluated, with 1.15, 14.62, and 3.71 ms, respectively, and OIA-BIE is four times more efficient than BIE. Numéro de notice : A2022-542 Affiliation des auteurs : non IGN Thématique : POSITIONNEMENT Nature : Article DOI : 10.1007/s10291-022-01285-5 Date de publication en ligne : 03/07/2022 En ligne : https://doi.org/10.1007/s10291-022-01285-5 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=101107 [article]

Ajustement en bloc des données de stations totales et de récepteurs GNSS dans les études de déformation / Joël Van Cranenbroeck in XYZ, n° 171 (juin 2022)

Public [article]  inXYZ > n° 171 (juin 2022) . - pp 25 - 32 Titre : Ajustement en bloc des données de stations totales et de récepteurs GNSS dans les études de déformation Type de document : Article/Communication Auteurs : Joël Van Cranenbroeck, Auteur ; Nicolas Van Cranenbroeck, Auteur Année de publication : 2022 Article en page(s) : pp 25 - 32 Note générale : Bibliographie Langues : Français (fre) Descripteur : [Vedettes matières IGN] Topographie [Termes IGN] auscultation d'ouvrage [Termes IGN] données GNSS [Termes IGN] méthode des moindres carrés [Termes IGN] modèle fonctionnel [Termes IGN] modèle stochastique [Termes IGN] surveillance d'ouvrage [Termes IGN] tachéomètre électronique Résumé : (Auteur) En 1988, le département de la géodésie de l’Institut géographique national de Belgique décida de contribuer aux relevés topographiques des zones urbaines en proposant deux innovations originales. Les nouvelles bases de données SIG urbaines bénéficiaient à cette époque d’un grand engouement de la part des pouvoirs publics. En général, les méthodes photogrammétriques étaient plébiscitées pour leur efficacité en termes de réalisation, mais au niveau de la qualité de la restitution ainsi que de l’interprétation des objets spatiaux, on était loin des espérances. Il était donc toujours indispensable de recourir à la topographie, non seulement pour améliorer la précision de certaines zones, mais également pour la mise à jour de ces bases de données année après année. La topographie avait vu également son évolution technique s’améliorer avec les nouvelles stations totales et les systèmes de traitement des données sur base de codage des informations attributaires des points, lignes et surfaces. Numéro de notice : A2022-522 Affiliation des auteurs : non IGN Thématique : POSITIONNEMENT Nature : Article nature-HAL : ArtSansCL DOI : sans Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=101067 [article]

Réservation

Réserver ce document

Exemplaires (2)

Code-barres	Cote	Support	Localisation	Section	Disponibilité
112-2022022	SL	Revue	Centre de documentation	Revues en salle	En circulation Exclu du prêt
112-2022021	SL	Revue	Centre de documentation	Revues en salle	Disponible

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

Public [article]  inJournal of geodesy > vol 96 n° 6 (June 2022) . - n° 39 Titre : The RTM harmonic correction revisited Type de document : Article/Communication Auteurs : R. Klees, Auteur ; Kurt Seitz, Auteur ; D.C. Slobbe, Auteur Année de publication : 2022 Article en page(s) : n° 39 Note générale : bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Géodésie physique [Termes IGN] analyse harmonique [Termes IGN] anomalie de pesanteur [Termes IGN] Auvergne [Termes IGN] correction des altitudes [Termes IGN] géoïde local [Termes IGN] harmonique sphérique [Termes IGN] hauteur ellipsoïdale [Termes IGN] méthode des moindres carrés [Termes IGN] modèle de géopotentiel local [Termes IGN] modèle numérique de terrain [Termes IGN] Norvège [Termes IGN] quasi-géoïde [Termes IGN] résidu Résumé : (auteur) In this paper, we derive improved expressions for the harmonic correction to gravity and, for the first time, expressions for the harmonic correction to potential and height anomaly. They need to be applied at stations buried inside the masses to transform internal values into harmonically downward continued values, which are then input to local quasi-geoid modelling using least-squares collocation or least-squares techniques in combination with the remove-compute-restore approach. Harmonic corrections to potential and height anomaly were assumed to be negligible so far resulting in yet unknown quasi-geoid model errors. The improved expressions for the harmonic correction to gravity, and the new expressions for the harmonic correction to potential and height anomaly are used to quantify the approximation errors of the commonly used harmonic correction to gravity and to quantify the magnitude of the harmonic correction to potential and height anomaly. This is done for two test areas with different topographic regimes. One comprises parts of Norway and the North Atlantic where the presence of deep, long, and narrow fjords suggest extreme values for the harmonic correction to potential and height anomaly and corresponding large errors of the commonly used approximation of the harmonic correction to gravity. The other one is located in the Auvergne test area with a moderate topography comprising both flat and hilly areas and therefore may be representative for many areas around the world. For both test areas, two RTM surfaces with different smoothness are computed simulating the use of a medium-resolution and an ultra-high-resolution reference gravity field, respectively. We show that the errors of the commonly used harmonic correction to gravity may be as large as the harmonic correction itself and attain peak values in areas of strong topographic variations of about 100 mGal. Moreover, we show that this correction may introduce long-wavelength biases in the computed quasi-geoid model. Furthermore, we show that the harmonic correction to height anomaly can attain values on the order of a decimetre at some points. Overall, however, the harmonic correction to height anomaly needs to be applied only in areas of strong topographic variations. In flat or hilly areas, it is mostly smaller than one centimetre. Finally, we show that the harmonic corrections increase with increasing smoothness of the RTM surface, which suggests to use a RTM surface with a spatial resolution comparable to the finest scales which can be resolved by the data rather than depending on the resolution of the global geopotential model used to reduce the data. Numéro de notice : A2022-414 Affiliation des auteurs : non IGN Thématique : POSITIONNEMENT Nature : Article DOI : 10.1007/s00190-022-01625-w Date de publication en ligne : 30/05/2022 En ligne : https://doi.org/10.1007/s00190-022-01625-w Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=100769 [article]

Accuracy issues for spatial update of digital cadastral maps / David Pullar in ISPRS International journal of geo-information, vol 11 n° 4 (April 2022)  

Public [article]  inISPRS International journal of geo-information > vol 11 n° 4 (April 2022) . - n° 221 Titre : Accuracy issues for spatial update of digital cadastral maps Type de document : Article/Communication Auteurs : David Pullar, Auteur ; Stephen Donaldson, Auteur Année de publication : 2022 Article en page(s) : n° 221 Note générale : bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Cadastre étranger [Termes IGN] Australie [Termes IGN] base de données foncières [Termes IGN] compensation [Termes IGN] données cadastrales [Termes IGN] lever cadastral [Termes IGN] méthode des moindres carrés [Termes IGN] mise à jour [Termes IGN] parcelle cadastrale [Termes IGN] plan parcellaire [Termes IGN] précision des données Résumé : (auteur) All geospatial data are updated periodically. Cadastral parcel mapping, however, has special update requirements that set it apart from other geospatial data. Mapped boundaries change continuously to fit with new survey plans. Additionally, new parcels have to be fitted and aligned with adjoining parcels to merge them into existing cadastral mapping. This is preferably performed by a spatial adjustment approach to systematically improve its accuracy over time. This paper adapts methods for analysis and adjustment of survey networks to improve the accuracy of cadastral mapping with better coordinate positioning and survey plan dimensions. Case studies for both hypothetical and real cadastral mapping are used to illustrate the issues and spatially resolve errors. Adjustment results achieve an accuracy consistent with other GIS layers and boundary features visible in high-resolution orthoimagery. Graphical charts based on stress–strain relationships provide a simplified means to interpret post-adjustment results to identify and fix potential errors. Numéro de notice : A2022-447 Affiliation des auteurs : non IGN Thématique : GEOMATIQUE Nature : Article DOI : 10.3390/ijgi11040221 Date de publication en ligne : 24/03/2022 En ligne : https://doi.org/10.3390/ijgi11040221 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=100305 [article]

Regularized integer least-squares estimation: Tikhonov’s regularization in a weak GNSS model / Zemin Wu in Journal of geodesy, vol 96 n° 4 (April 2022)  

Public [article]  inJournal of geodesy > vol 96 n° 4 (April 2022) . - n° 22 Titre : Regularized integer least-squares estimation: Tikhonov’s regularization in a weak GNSS model Type de document : Article/Communication Auteurs : Zemin Wu, Auteur ; Shaofeng Bian, Auteur Année de publication : 2022 Article en page(s) : n° 22 Note générale : bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Géodésie spatiale [Termes IGN] affaiblissement géométrique de la précision [Termes IGN] méthode des moindres carrés [Termes IGN] phase GNSS [Termes IGN] positionnement par GNSS [Termes IGN] régularisation de Tychonoff [Termes IGN] résolution d'ambiguïté Résumé : (auteur) The strength of the GNSS precise positioning model degrades in cases of a lack of visible satellites, poor satellite geometry or uneliminated atmospheric delays. The least-squares solution to a weak GNSS model may be unreliable due to a large mean squared error (MSE). Recent studies have reported that Tikhonov’s regularization can decrease the solution’s MSE and improve the success rate of integer ambiguity resolution (IAR), as long as the regularization matrix (or parameter) is properly selected. However, there are two aspects that remain unclear: (i) the optimal regularization matrix to minimize the MSE and (ii) the IAR performance of the regularization method. This contribution focuses on these two issues. First, the “optimal” Tikhonov’s regularization matrix is derived conditioned on an assumption of prior information of the ambiguity. Second, the regularized integer least-squares (regularized ILS) method is compared with the integer least-squares (ILS) method in view of lattice theory. Theoretical analysis shows that regularized ILS can increase the upper and lower bounds of the success rate and reduce the upper bound of the LLL reduction complexity and the upper bound of the search complexity. Experimental assessment based on real observed GPS data further demonstrates that regularized ILS (i) alleviates the LLL reduction complexity, (ii) reduces the computational complexity of determinate-region ambiguity search, and (iii) improves the ambiguity fixing success rate. Numéro de notice : A2022-262 Affiliation des auteurs : non IGN Thématique : POSITIONNEMENT Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.1007/s00190-021-01585-7 Date de publication en ligne : 28/03/2022 En ligne : https://doi.org/10.1007/s00190-021-01585-7 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=100251 [article]

Influence of determinant factors towards soil erosion using ordinary least squared regression in GIS domain / Imran Ahmad in Applied geomatics, vol 14 n° 1 (March 2022)  

Permalink

Deriving a tree growth model from any existing stand growth model / Quang V. Cao in Canadian Journal of Forest Research, Vol 52 n° 2 (February 2022)  

Permalink

Efficient variance component estimation for large-scale least-squares problems in satellite geodesy / Yufeng Nie in Journal of geodesy, vol 96 n° 2 (February 2022)  

Permalink

Geoid determination through the combined least-squares adjustment of GNSS/levelling/gravity networks – a case study in Linyi, China / Dongmei Guo in Survey review, Vol 53 n° 381 (November 2021)  

Permalink

A constrained extended Kalman filter based on LS-VCE formulated by condition equations with prediction of cross-covariances / Vahid Mahboub in Survey review, Vol 53 n° 380 (September 2021)  

Permalink

JUST: MATLAB and python software for change detection and time series analysis / Ebrahim Ghaderpour in GPS solutions, vol 25 n° 3 (July 2021)  

Permalink

High-resolution geoid modeling using least squares modification of Stokes and Hotine formulas in Colorado / Mustafa Serkan Işık in Journal of geodesy, vol 95 n° 5 (May 2021)  

Permalink

Increasing efficiency of the robust deformation analysis methods using genetic algorithm and generalised particle swarm optimisation / Mehmed Batilović in Survey review, Vol 53 n° 378 (May 2021)  

Permalink

New algorithms for spherical harmonic analysis of area mean values over blocks delineated by equiangular and Gaussian grids / Rong Sun in Journal of geodesy, vol 95 n° 5 (May 2021)  

Permalink

Le nivellement par GNSS chez SNCF Réseau / Antoine Beuvain Pacheco in XYZ, n° 166 (mars 2021)

Permalink