Vertical gravity gradient, as a change of gravity with the change in height, is a significant physical quantity used in many geodetic and geophysical modeling applications. In this research, we used ...a normal gravity field and digital terrain models to model the vertical gravity gradient without using other sources of information such as global geopotential models, results of gravity measurements, or digital density models of topographic masses. We measured vertical gravity gradients by relative gravimeters at 120 points, which we used as validation values for a typical forward modeling problem. In all calculations, we assumed a constant density of topographic masses above the ellipsoid and accounted for the effects of the Earth's curvature. In the territory of Slovenia, where a digital terrain model with a resolution of 1 × 1 m is available, the differences between the measured and modeled values of the vertical gravity gradients are on average − 9.3 μGal/m with a standard deviation of 12.3 μGal/m. For the territory of Serbia, using a digital terrain model with a resolution of 25 × 25 m, the same differences were obtained with an average of − 7.8 μGal/m and a standard deviation of 21.4 μGal/m. It can be said that the quality of the modeled values of vertical gravity gradients is directly related to the resolution of the digital terrain model.
The existing Bouguer anomaly map, which covers the territory of the Republic of Slovenia is a few decades old. Since then, quite a few new gravimetric measurements (data) for the territory of ...Slovenia as well as high quality digital terrain models that are needed for creating such a map have been made available. The methodology and standards for creating gravity anomaly maps are also changing. Thus, the national Bouguer anomaly map was updated. There were some gross errors detected in the set of old gravimetric data. Additionally, the influence of new updated gravimetric data was analyzed. The comparison of the various maps and the analysis of the influence of input gravimetric data indicates that the new gravimetric data of Slovenia has a significant influence on the creation of the gravimetric anomaly maps for Slovenia (even over 30 mGals at some points).
Tokrat sta bila dodana dva nova referenčna koordinatna sistema in dve novi transformaciji, in sicer kot podpora uvajanju trirazsežnostnih (3R) prostorskih podatkovnih zbirk. 2 NOVE EPSG-KODE Oba na ...novo določena referenčna koordinatna sistema temeljita na že obstoječih in sta torej sestavljena referenčna koordinatna sistema (angl. compound coordinate reference system), ki vključujeta tako horizontalno kot tudi vertikalno sestavino prostorskega referenčnega koordinatnega sistema. GFZ Data Services. Open Access to Regional Geoid Models: The International Service for the Geoid.
The current Slovenian terrestrial reference frame (D96-17) is a static frame based on GNSS technology. An additional transformation connecting it with the new realisation of ETRS89 accepted by EUREF ...(D17) gives the D96-17 a specific character. In order to ensure a high-quality national terrestrial reference frame, connection to the current realisation of ITRS is needed. This change is particularly important in the light of the intended transition to the semi-kinematic terrestrial reference frame, supported by a national geo-kinematic model. Transformations between the current national and international terrestrial reference frames are discussed in detail in the present paper. Processes, equations, and parameters of datum transformations are given in both directions (forward and inverse), step-by-step and direct ones, rigorous and simplified (approximate). Furthermore, an analysis of coordinate differences between current Slovenian and international terrestrial reference frames and an analysis of coordinate errors for various simplifications of transformation between both reference frames are given. This allows users to choose an optimal transformation solution to meet their requirements. The role and importance of transformations under consideration in the positioning procedures and the precise navigation are also addressed.
Transformations between the current national and international terrestrial reference frames are discussed in detail in the present paper. Furthermore, an analysis of coordinate differences between ...current Slovenian and international terrestrial reference frames and an analysis of coordinate errors for various simplifications of transformation between both reference frames are given. Mednarodna zveza za geodezijo - IAG (International Association of Geodesy) pa daje prednost terminoma terestrični referenčni sistem - TRS (angl. terrestrial reference system) in terestrični referenčni sestav - TRF (angl. terrestrial reference frame), ki je konkretna realizacija prvega. Za »TRF, epoha t« je v nadaljevanju uporabljen krajši zapis TRF@t. Mednarodni terestrični referenčni sistem - ITRS (International Terrestrial Reference System) je sistem s središčem v težišču Zemlje (geocentričen); začetno orientacijo v epohi 1984,0 je podal Mednarodni urad za čas - BIH (Bureau International de l'Heure) in se za vsakokratno novo realizacijo ohranja ob pogoju, da se sistem ne vrti (angl. no-net-rotation condition), pri čemer se upoštevajo tektonska dogajanja na celotni Zemlji (Petit in Luzum, 2010, str. 34).
The current Slovenian terrestrial reference frame (D96-17) is a static frame based on GNSS technology. An additional transformation connecting it with the new realisation of ETRS89 accepted by EUREF ...(D17) gives the D96-17 a specific character. In order to ensure a high-quality national terrestrial reference frame, connection to the current realisation of ITRS is needed. This change is particularly important in the light of the intended transition to the semi-kinematic terrestrial reference frame, supported by a national geo-kinematic model. Transformations between the current national and international terrestrial reference frames are discussed in detail in the present paper. Processes, equations, and parameters of datum transformations are given in both directions (forward and inverse), step-by-step and direct ones, rigorous and simplified (approximate). Furthermore, an analysis of coordinate differences between current Slovenian and international terrestrial reference frames and an analysis of coordinate errors for various simplifications of transformation between both reference frames are given. This allows users to choose an optimal transformation solution to meet their requirements. The role and importance of transformations under consideration in the positioning procedures and the precise navigation are also addressed.
Dopolnjena in posodobljena so bila navodila za zgostitve EUREF (tj. za nove realizacije ETRS89) in razvito spletno orodje za klasifikacijo in izbor referenčnih GNSS-postaj za izbrano časovno obdobje, ...ki bo zelo koristno pri obdelavi EUREF-ovih izmer (dve predstavitvi Juliette Legrand). Pri tem bo ključen multidisciplinaren pristop, kar se udejanja v okviru projekta EPOS (European Plate Observing System), pri katerem sodeluje tudi Slovenija. Sestanek na temo projekta CEGRN (Central European GNSS Research Network), pri katerem sodeluje tudi Slovenija, sta vodila Alessandro Caporali in Joaquín Zurutuza.
Regional gravimetric survey of central Slovenia Medved, Klemen; Kuhar, Miran; Koler, Božo
Measurement : journal of the International Measurement Confederation,
March 2019, 2019-03-00, 20190301, Letnik:
136
Journal Article
Recenzirano
Display omitted
•Detailed presentation of regional gravimetric survey.•Processing of gravity survey data.•Impact of the new gravimetric data on modelling the height reference surface.
This paper ...presents the regional gravimetric survey of the central part of the Republic of Slovenia. The need for a new gravimetric survey, the survey plan and the actual field measurements are presented. Data processing, control calculations, data adjustment in the form of a gravimetric network and accuracy estimations of the results obtained during the regional gravimetric survey are described. Furthermore, the impact the new gravimetric data had on the quasigeoid model determined in 2016 and consequentially on determining normal height by GNSS levelling was analysed. The analysis were based on the comparison of the normal heights determined by GNSS levelling and the control points obtained from the 2010 and 2016 quasigeoid models. The results show that the new gravimetric data improved the newly calculated quasigeoid model or height reference surface of Slovenia and consequently made the determination of the normal heights by GNSS levelling more precise. The comparison of old and new height reference surfaces shows there are differences in investigated area from −6.9 cm to +9.0 cm and mean difference is 1.5 cm.
PROTI NOVI REALIZACIJI ETRS89 Medved, Klemen; Berk, Sandi
Geodetski vestnik,
06/2017, Letnik:
61, Številka:
2
Journal Article
Recenzirano
Odprti dostop
Na letošnjem simpoziju so bile sprejete štiri resolucije, ki prinašajo smernice za nadaljnje delo na tem področju. 1NEKAJ AKTUALNIH ZADEV S SIMPOZIJA Letos je bil sprejet nov (posodobljen) statut ...EUREF (EUREF Terms of References), ki je nadomestil do sedaj veljavnega iz leta 2008. Med spremembami velja omeniti preimenovanje tehnične delovne skupine (Technical Working Group - TWG) v upravni odbor (Governing Board - GB). V zadnjih letih je tudi veliko poudarka na vzpostavitvi evropskega sistema za spremljanje tektonike (European Plate Observing System - EPOS), katerega namen je združiti različne geoznanosti pod eno okrilje. Key Results of ITRF2014 and Implication to ETRS89 Realization. 26th Symposium of the IAG Subcommission for Europe (EUREF), Donastia/San Sebastián, Španija, 25.-27. maj 2016. http://www.euref.eu/symposia/2016SanSebastian/01-02-Altamimi.pdf EPOS (2017). European Plate Observing System. https://www.epos-ip.org/ EUREF (2017).
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