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GPS code phase variations (CPV) for GNSS receiver antennas and their effect on geodetic parameters and ambiguity resolution / Tobias Kersten in Journal of geodesy, vol 91 n° 6 (June 2017)  

Public [article]  inJournal of geodesy > vol 91 n° 6 (June 2017) . - pp 579 - 596 Titre : GPS code phase variations (CPV) for GNSS receiver antennas and their effect on geodetic parameters and ambiguity resolution Type de document : Article/Communication Auteurs : Tobias Kersten, Auteur ; Steffen Schön, Auteur Année de publication : 2017 Article en page(s) : pp 579 - 596 Note générale : Bibliographie Langues : Anglais (eng) Descripteur : [Termes IGN] antenne GNSS [Termes IGN] centre de phase [Termes IGN] erreur de mesure [Termes IGN] phase GNSS [Termes IGN] résolution d'ambiguïté [Vedettes matières IGN] Traitement de données GNSS Résumé : (Auteur) Precise navigation and geodetic coordinate determination rely on accurate GNSS signal reception. Thus, the receiver antenna properties play a crucial role in the GNSS error budget. For carrier phase observations, a spherical radiation pattern represents an ideal receiver antenna behaviour. Deviations are known as phase centre corrections. Due to synergy of carrier and code phase, similar effects on the code exist named code phase variations (CPV). They are mainly attributed to electromagnetic interactions of several active and passive elements of the receiver antenna. Consequently, a calibration and estimation strategy is necessary to determine the shape and magnitudes of the CPV. Such a concept was proposed, implemented and tested at the Institut für Erdmessung. The applied methodology and the obtained results are reported and discussed in this paper. We show that the azimuthal and elevation-dependent CPV can reach maximum magnitudes of 0.2–0.3 m for geodetic antennas and up to maximum values of 1.8 m for small navigation antennas. The obtained values are validated by dedicated tests in the observation and coordinate domain. As a result, CPV are identified to be antenna- related properties that are independent from location and time of calibration. Even for geodetic antennas when forming linear combinations the CPV effect can be amplified to values of 0.4–0.6 m. Thus, a significant fractional of the Melbourne–Wübbena linear combination. A case study highlights that incorrect ambiguity resolution can occur due to neglecting CPV corrections. The impact on the coordinates which may reach up to the dm level is illustrated. Numéro de notice : A2017-285 Affiliation des auteurs : non IGN Thématique : POSITIONNEMENT Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.1007/s00190-016-0984-8 En ligne : http://dx.doi.org/10.1007/s00190-016-0984-8 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=85318 [article]

Geodetic monitoring of subrosion-induced subsidence processes in urban areas / Tobias Kersten in Journal of applied geodesy, vol 11 n° 1 (March 2017)  

Public [article]  inJournal of applied geodesy > vol 11 n° 1 (March 2017) . - pp 21 - 30 Titre : Geodetic monitoring of subrosion-induced subsidence processes in urban areas Type de document : Article/Communication Auteurs : Tobias Kersten, Auteur ; Martin Kobe, Auteur ; Gerald Gabriel, Auteur ; Ludger Timmen, Auteur ; Steffen Schön, Auteur ; Detlef Vogel, Auteur Année de publication : 2017 Article en page(s) : pp 21 - 30 Note générale : Bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Applications de géodésie spatiale [Termes IGN] église [Termes IGN] gravimétrie [Termes IGN] Hambourg [Termes IGN] nivellement [Termes IGN] positionnement par GNSS [Termes IGN] réseau de surveillance géophysique [Termes IGN] subsidence [Termes IGN] surveillance géologique [Termes IGN] Thuringe [Termes IGN] tour (bâtiment) [Termes IGN] zone urbaine Résumé : (Résumé) The research project SIMULTAN applies an advanced combination of geophysical, geodetic, and modelling techniques to gain a better understanding of the evolution and characteristics of sinkholes. Sinkholes are inherently related to surface deformation and, thus, of increasing societal relevance, especially in dense populated urban areas. One work package of SIMULTAN investigates an integrated approach to monitor sinkhole-related mass translations and surface deformations induced by salt dissolution. Datasets from identical and adjacent points are used for a consistent combination of geodetic and geophysical techniques. Monitoring networks are established in Hamburg and Bad Frankenhausen (Thuringia). Levelling surveys indicate subsidence rates of about 4–5 mm per year in the main subsidence areas of Bad Frankenhausen with a local maximum of 10 mm per year around the leaning church tower. Here, the concept of combining geodetic and gravimetric techniques to monitor and characterise geological processes on and below the Earth's surface is exemplary discussed for the focus area Bad Frankenhausen. For the different methods (levelling, GNSS, relative/absolute gravimetry) stable network results at identical points are obtained by the first campaigns, i.e., the results are generally in agreement. Numéro de notice : A2017-281 Affiliation des auteurs : non IGN Thématique : POSITIONNEMENT Nature : Article DOI : 10.1515/jag-2016-0029 En ligne : https://doi.org/10.1515/jag-2016-0029 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=85314 [article]

Potential of GPS common clock single-differences for deformation monitoring / Steffen Schön in Journal of applied geodesy, vol 10 n° 1 (March 2016)  

Public [article]  inJournal of applied geodesy > vol 10 n° 1 (March 2016) . - pp 45 - 52 Titre : Potential of GPS common clock single-differences for deformation monitoring Type de document : Article/Communication Auteurs : Steffen Schön, Auteur ; Hue Kiem Pham, Auteur ; Tobias Kersten, Auteur ; Julia Leute, Auteur ; Andreas Bauch, Auteur Année de publication : 2016 Article en page(s) : pp 45 - 52 Note générale : bibliographie Langues : Anglais (eng) Descripteur : [Termes IGN] déformation géométrique [Termes IGN] hauteur ellipsoïdale [Termes IGN] horloge [Termes IGN] positionnement cinématique [Termes IGN] récepteur GNSS [Termes IGN] simple différence [Vedettes matières IGN] Traitement de données GNSS Résumé : (auteur) Global satellite navigation systems (GNSS) are a standard measurement device for deformation monitoring. In many applications, double-differences are used to reduce distance dependent systematic effects, as well as to eliminate the receiver and satellites clock errors. However, due to the navigation principle of one way ranging used in GPS, the geometry of the subsequent adjustment is weakened. As a result, the height component is generally determined three times less precisely than the horizontal coordinates. In addition, large correlations between the height and elevation dependent effects exist such as tropospheric refraction, mismodelled phase center variations, or multipath which restricts the attainable accuracy. However, for a kinematic analysis, i. e. for estimating high rate coordinate time series, the situation can be significantly improved if a common clock is connected to different GNSS receivers in a network or on a baseline. Consequently, between-station single-differences are sufficient to solve for the baseline coordinates. The positioning geometry is significantly improved which is reflected by a reduction of the standard deviation of kinematic heights by about a factor 3 underlining the benefits of this new approach. Real data from baselines at the Physikalisch-Technische Bundesanstalt campus at Braunschweig where receivers are connected over 290 m via an optical fiber link to a common clock was analysed. Numéro de notice : A2016-553 Affiliation des auteurs : non IGN Thématique : POSITIONNEMENT Nature : Article DOI : 10.1515/jag-2015-0029 En ligne : http://dx.doi.org/10.1515/jag-2015-0029 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=81700 [article]