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).
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.
To perform geodetic measurements of displacements of the ground and manmade constructions, stabilised reference points are needed from which control points on the object or its surroundings could be ...measured. Reference points are most commonly stabilised with reinforced concrete pillars; however, they are not always constructed in an appropriate manner. The influence of temperature variation within a pillar on the position of the fixed screw for forced centring is not negligible and should be considered when performing precise measurements. In this research paper, the displacement of a pillar was calculated as a result of the temperature changes in the pillar, and then an experiment was performed in which the pillar was heated from one side, and the horizontal displacement of the fixed screw for forced centring was measured. Both, calculations and measurements, show that at a temperature difference of 16.2 °C, the fixed screw on a 1.5 m high pillar moves by approximately 1 mm, which is a displacement that should be taken into account in precise measurements.
This paper describes the quality determination of heights above mean sea level using RTK GNSS-levelling and new height reference surface SLO_VRP2016/Koper on the city area of Ljubljana. At 57 chosen ...benchmarks, quasigeoid heights were determined using ellipsoidal heights, determined with RTK GNNS-levelling technique and heights above mean sea level in the new height system SVS2010. The measured quasigeoid heights were compared with values interpolated from the new height reference surface SLO_VRP2016/Koper.
This paper deals with the effects that displacements of the measuring pillar have on precise geodetic measurements. The changes in the position of the control points on the object or its surroundings ...can only be determined with well stabilized and stable reference points. These points are usually stabilized with measuring pillars which are not always constructed in an optimal manner. If they are placed in a dark tube with a high absorption factor, solar heating on one side of the pillar can cause the pillar to deflect considerably due to the temperature difference on the two sides of the pillar. This paper presents the influence of such a displacement, if the pillar is a survey point, orientation point, or control point. We show that even small displacement of the survey point can have important influence on all measurements and that the error in some cases significantly increases, e.g., if the standard deviations of the coordinates of the survey point are 1 mm and their covariance is assumed to be zero, the standard deviation of the distance between measured and exact position of the control point exceeds the value of 2.2 mm.
In this article, an overview of the height geodetic data of Slovenia that were determined on a basis of observations from various tide gauges along the Adriatic coast is presented. This is followed ...by the definition of the Koper height geodetic datum as a part of a new height system of Slovenia. The height datum was determined on the basis of observations at Koper tide gauge, the rate of sea level change in Koper, and taking into account the local stability of the tide gauge.
The height datum was determined on the basis of observations at Koper tide gauge, the rate of sea level change in Koper, and taking into account the local stability of the tide gauge. Geodetic ...observations and global reference frame contributions to understanding sea-level rise and variability. Tide gauge and GPS measurements of crustal motion and sea level rise along the eastern margin of Adria. The Difficulties in Using Tide Gauges to Monitor Long-Term Sea Level Change. https://www.fig.net/resources/monthly_articles/2010/july_2010/ july_2010_hannah.pdf, pridobljeno 10.
Based on the height differences of the benchmarks between the old and the new height systems stabilised in the area of eastern Slovenia, we determined the height transformation surface for two areas ...of different sizes. For both areas we analyzed the influence of different interpolation methods and the influence of using height differences of benchmarks of different orders of the levelling net. KEY WORDS height transformation surface, height system, vertical datum, interpolation, average height, SiVis software 1 UVOD V Sloveniji je do konca leta 2018 veljal star visinski sistem z oznako SVS2000, ki je temeljil na višinskem datumu Trst. Na podlagi njihove analize smo za izdelavo VTP uporabili metodo kriging (Pilz in Spöck, 2007; Arun, 2016), metodo inverzne razdalje (angl. inverse distance) (Hessl et al., 2007; Ayeni in Samuel, 2014) in metodo nepravilnih trikotnikov (angl. triangulation) (Ayeni in Samuel, 2014).
In this work, we analyzed the quality of height transformation between the old height system SVS2000 (vertical datum Trieste) and the new height system SVS2010 (vertical datum Koper). Based on the ...height differences of the benchmarks between the old and the new height systems stabilised in the area of eastern Slovenia, we determined the height transformation surface for two areas of different sizes. For both areas we analyzed the influence of different interpolation methods and the influence of using height differences of benchmarks of different orders of the levelling net. We found that the quality of height transformation is satisfactory for most surveying services. We have also analyzed the quality of the height transformation based on the average height difference of the benchmarks by using the SiVis software, which is intended for the transformation of ellipsoidal heights obtained by GNSS measurements, between the old and the new height systems.
PDF
