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Introduction
Current institution
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September 2012 - January 2021
University of Zagreb, Faculty of geodesy
Position
- Research Assistant
Publications
Publications (74)
Accuracy assessment of digital elevation models (DEMs) plays an important role in facing their use in geoscience applications. This study investigates the vertical accuracy of most recently published versions of global DEMs over Croatia: 1 arc-minute global relief model (ETOPO1), Global 30 Arc-Second Elevation (GTOPO30), SRTM30+, Global Multi-resol...
**full text in attachment****cijeloviti tekst u privitku**
elipsoid, koordinatni referentni sustavi, konverzija koordinata, transformacija koordinata, visine, koordinatni referentni sustavi i transformacije koordinata u Republici Hrvatskoj, redukcija mjerenih veličina na plohu elipsoida, glavni geodetski zadaci, duljine geodetskih linija, rješenja...
This paper studies the contribution of airborne gravity data to improvement of gravimetric geoid modelling across the mountainous area in Colorado, USA. First, airborne gravity data was processed, filtered, and downward-continued. Then, three gravity anomaly grids were prepared; the first grid only from the terrestrial gravity data, the second grid...
The primary objective of the 1-cm geoid experiment in Colorado (USA) is to compare the numerous geoid computation methods used by different groups around the world. This is intended to lay the foundations for tuning computation methods to achieve the sought after 1-cm accuracy, and also evaluate how this accuracy may be robustly assessed. In this e...
The AlpArray Gravity Research Group (AAGRG), as part of the European AlpArray program, focuses on the compilation of a homogeneous surface-based gravity data set across the Alpine area. In 2017 10 European countries in the Alpine realm agreed to contribute with gravity data for a new compilation of the Alpine gravity field in an area spanning from...
The miniaturisation and decrease of price are amongst the main current trends in the area of Global Navigation Satellite Systems (GNSS) receivers. Besides standalone receivers also receivers incorporated into Android devices can provide raw GNSS measurements thus enabling much wider options, formerly restricted to devices of much higher price. The...
A destructive Mw = 6.2 earthquake struck NW Croatia on 29 December 2020, ranking among the most hazardous events in the country in the last century. This study assesses the impact of the earthquake on the permanent geodetic stations of the Croatian national positioning system. Using a novel approach, we combined positioning station data with satell...
More information: https://github.com/thierweber/kreuzkirche-3DModel.
3D Model of the Kreuzkirche in Zürich, Switzerland created from LiDAR and photogrammetric data.
In the span of a semester at ETH Zurich, a high-detail, digital 3D model of the exterior of Kreuzkirche in Hottingen ZH was reconstructed. Scoping the full workflow of modern cultural...
The integration of the color information from RGB cameras with the point cloud geometry is used in numerous applications. However, little attention has been paid on errors that occur when aligning colors to points in terrestrial laser scanning (TLS) point clouds. Such errors may impact the performance of algorithms that utilize colored point clouds...
The variability of the geomagnetic field is a result of changes in the Earth's core field as well as the composition of the Earth's crust. In order to correctly describe the magnetic field it is important to perform measurements, create models and other geomagnetic products that describe the time variations and anomalies. The report presents the fi...
Deformations affect the structural integrity of wind turbine towers. The health of such structures is thus assessed by monitoring. The majority of sensors used for this purpose are costly and require in situ installations. We investigated whether Multiple-Input Multiple-Output Synthetic Aperture Radar (MIMO-SAR) sensors can be used to monitor wind...
The main goal of this contribution is to compare different approaches for modelling the omission error which could be one error source among many others in geoid determination. To do so we employ gravity disturbances over three test areas, namely, Czechia, Slovakia and southern Colorado. Firstly we subtract the high-frequency part of the gravitatio...
1. Why coordinate reference systems and geodetic networks are needed for FCC
2. Summary of CERN’s existing solutions
3. How coordinate reference systems and geodetic networks should be designed and implemented
Swisstopo Kolloquium, Vortragsreihe
Models of gravity corrections and anomalies are created and distributed over the territory of the Republic of Croatia, including the Adriatic and Dinarides regions. Published models cover the study area between 42.0○N < ϕ < 46.6○N and 13.0○E < λ < 19.5○E with a 1′ × 1′ resolution. Distributed models include gravity corrections and anomalies of norm...
At the very end of the year 2020, at 29th of December, hazard earthquake of M=6.2 hit near Petrinja, at NW of Croatia. Earthquake have been felt in a circumstance of a 400 kilometers, leaving in an epicenter vicinity inconceivable damage, devastated towns and obstructed lives. In order to obtain the first emergency crisis numbers over the impact of...
The precision of geodetic measurements is reliable as much as the reference on which the measurements relies on. From the aspect of todays' most used geodetic method, the GNSS measurements, its reference is defined through a national reference frame established with corresponding reference stations. Hazardous earthquake of M=6.2 occurred in NW Croa...
In this study we investigate practical feasibility and horizontal accuracy of 10-minute long static GNSS measurements acquired using an Android-based Xiaomi Mi8 smartphone. Measurements were collected during 40 days on three points with different tree canopy conditions. The accuracy was analyzed with regard to measurement conditions, usage of groun...
At the very end of the year 2020, on 29 December, a hazardous earthquake of Mw = 6.2 hit the area of Petrinja and its surroundings, in the NW of Croatia. The earthquake was felt across the area of 400 km, leaving an inconceivable damage in the vicinity of the epicenter, devastated towns and ruined lives. In order to map the spreading of earthquake...
**full text in attachment****cijeloviti tekst u privitku**
elipsoid, geoid, potencijal i ubrzanje sile teže, gravimetrija, topografske redukcije i anomalije, globalni geopotencijalni modeli
ellipsoid, geoid, gravity potential, gravity acceleration, gravimetry, topographic reductions and anomalies, global geopotential models, coordinate transforma...
The AlpArray Gravity Research Group (AAGRG), as part of the European AlpArray program, focuses on the compilation of a homogeneous surface-based gravity dataset across the Alpine area. From this data set, Bouguer- and Free Air anomalies are calculated and presented here. In 2016/17 ten European countries in the Alpine realm have agreed to contribut...
The hardware of new-generation smartphones enables navigation, positioning and surveying (NPS) using Global Navigation Satellite Systems (GNSS). Moreover, unprecedented progress has been made in the last few years related to the accuracy and reliability of smartphone NPS giving three significant changes: (1) accessing raw code and carrier GNSS meas...
Popravak kompasa je kut koji u točki na karti definira projekcija magnetskog meridijana točke s ordinatom kartografskog projekcijskog sustava, a jednak je razlici magnetske deklinacije i konvergencije meridijana. U praksi topografsko-geodetske pripreme i osiguranja primjenjuje se tzv. radni popravak kompasa, u kojemu se deklinacija sastoji od dnevn...
Large number of bridges in Europe is at the end of their life span, while the frequency of occurrence for extreme climatic events, driven by climate change, is increasing. Floods influence morphodynamic changes in the riverbed, such as scouring of the riverbed next to the bridge substructure, that can undermine the overall stability of the bridge....
Tides have largest impact on gravity measurements compared to all other environmental effects. They are a direct result of the gravitational forces of the planetary bodies, mainly the Moon and the Sun. The magnitude of tidal effects depends on the relative position of planetary bodies around the Earth and can be computed from the astronomical ephem...
In this presentation, made on the occasion of 100 years of the death of the world famous Earth scientist Loránd Eötvös, an overview of gravimetry and geoid modelling in Croatia was shown, with end view on Eötvös's influence on gravity and magnetic field research in Croatia.
OPEN ACCESS ARTICLE ON LINK:
http://geofizika-journal.gfz.hr/vol_36/No1/36-1_Varga_et_al.pdf
High-resolution digital elevation models (DEMs) have become available in the last decade. They are used in geodesy and geophysics as the main data for modeling of topographic mass effects included in gravimetric and gradiometric measurements. In modeling...
One of the main challenges in physical geodesy today is achieving the 1-centimeter gravimetric quasi-geoid model, since a model of such accuracy could be used in the definition and realization of the height reference frame. One of the main obstacles in this challenge is the lack of terrestrial gravity data or its uneven distribution. Therefore, the...
The 2nd Geomagnetic Information Renewal Cycle started in 2017, pursuant to a request from the State Geodetic Administration and Ministry of Defence to ensure actual declination and its annual variation across the territory of Republic of Croatia. A test survey was performed at POKUpsko as part of the project in 2017. The PRM1 Primary Repeat Station...
Trgovanje prostornim informacijama i pružanje usluga povezanih s prostornim informacijama jedan su od osnovnih segmenata gospodarstva neke države. Odnos tržišnih rezultata tog segmenta i ekonomskog stanja nekog područja duboko je isprepleten - pozitivni tržišni rezultati u trgovanju prostornim informacijama najčešće su posljedica ekonomskog boljitk...
The existing multi-mission altimeter observation system meets most of the requirements for monitoring of the absolute sea level and its change over time. However, with the increasing number of the studies on the impact of the sea level rise in coastal areas, a special attention should be paid on reevaluating and improving the absolute sea level mod...
In this study results will be presented on the numerical experiments and comparisons of two regional geoid modelling approaches: Remove-Compute-Restore (RCR) and Least Squares Modification of Stokes' Formula with Additive Corrections (LSMSA, also known as KTH). While RCR has been used for few decades, LSMSA approach has gained wide popularity in th...
Models of geomorphometric parameters and drainage networks are widely used in many scientific and civilian branches and activities. They are created using the Earth’s land surface data, which are today mostly represented by digital elevation models (DEMs). The main objective of this study is to create models of slope, aspect, and drainage networks...
In the last 200 years, various definitions of the geoid have been given. One of the given definitions is that it is the surface of constant potential W_0. The term geoid is used synonymously for few similar surfaces (such as quasi-geoid or hybrid quasi-geoid), and this depends on particular scientific or practical application. One of its main appli...
Topographic masses are known to have a significant effect in regional geoid modeling. In fact, many authors have emphasized that short wavelengths filtering of gravity signal is crucial in recovering geoid undulations from gravity data. Digital elevation (DEM) and bathymetric models (DBM) are data sources for computation of topographic effects whic...
The registers of the accurate and accessible digital maritime boundaries, with defined territorial claims and property rights, are of the vital importance for the protection of natural resources and development of the economy of each country. Such registers that allow defining, visualising, recording and managing the rights in marine space can be r...
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One of the ultimate goals in geodesy, a 1 cm geoid model, is still unreachable for most of the areas worldwide. Several theoretical, methodological, numerical and data problems will have to be resolved in order to achieve it. The main motivation of this research is in making method...
Fundamental task of geodetic reference systems is to provide horizontal and vertical position with highest accuracy. Conceptually and practically, one of the main issues of 30 cadastre is definition and realization of height reference system. Nowadays, accuracy requirements together with the profitability and homogeneity of the coordinates are grea...
Vertical coordinates are the basic component of 30 cadastre, but so far they are rarely discussed during conceptual designing and solution proposal of 30 cadastre. The main reason for that is routine determination of vertical coordinates during field work. However, during the realization 30 cadastre appear many theoretical and practical problems. S...
Satellite based global gravity field models represent Earth's long-wavelength static or time-variable gravity field. Their progress and development in the recent years has been induced by successful satellite missions, such as GOCE, GRACE and CHAMP and this will continue in the future missions. Resolution and agreement with quality terrestrial data...
Topographic and topoisostatic reductions of gravity field measurements are important in geodesy and geophysics. Reductions filter high frequencies from gravity which are then used in geoid modelling or investigations of the Earth's structure. Practical computations of reductions are performed using digital elevation/bathymetric models as input data...
This paper presents empirical research on coordinate transformation models that enable coordinate transformations between the historical astro-geodetic datums and datums related to the European Terrestrial Reference System (ETRS), through a case study of the Republic of Croatia. Thirteen models were investigated for the transformation from the hist...
It is well-known that the Mediterranean Sea is challenging both in terms of geoid and Mean Dynamic Ocean Topography (MDOT) determination due to its geodynamic and oceanic features. Poor gravity data coverage and their outdated nature, along with the fact that the gravity and geoid slopes in the Mediterranean reach significant values with high varia...
Data, models, publications, and software are fundamental part of research in physical geodesy and related scientific fields. They are continuously published and their finding, accessing and preparation for usage require investing significant efforts and time. This is due to: (1) different international and local, private and public data publishers,...
With nowadays high resolution Global Geopotential Models (GGMs), traditional geoid approximation with the Remove-Compute-Restore (RCR) procedure needs revisiting both in terms of the numerical and the methodological steps followed. This becomes evident if one considers the high degree of expansion of the latest combined GGMs, corresponding to frequ...
Modernization of height reference systems has started in the past decade in the field of basic surveying work in the world. It was triggered mostly by intensive development and daily use of satellite positioning methods, as well as by increased accuracy of global and regional gravity models. The accomplishment of one-centimetre accurate geoid model...
The Mediterranean Sea has always been a lab for geosciences, given its geodynamic peculiarities, the large short-scale variations of the gravity field and the complex circulation. Within the GEOMED 2 project, new improved representations of the Mediterranean marine geoid have been deemed as necessary, so that the Mean Dynamic sea surface Topography...
The unique features of the Mediterranean Sea, with its large gravity variations, complex circulation, and geodynamic peculiarities have always constituted this semi-enclosed sea area as a unique geodetic, geodynamics and ocean laboratory. The main scope of the GEOMED 2 project is the collection of all available gravity, topography/bathymetry and sa...
Conformal coordinate transformations very often are not accurate enough to be used for the coordinate transformations between local and global geodetic datums because of the inhomogeneity of the spatial data in different geodetic datums. Therefore, distortion modeling is used to improve the accuracy of the coordinate transformations. This paper pre...
Several coordinate transformation models enable performing of the coordinate transformations between the historical astro-geodetic datums, which were utilized before the GNSS (Global Navigation Satellite System) technologies were developed, and datums related to the International Terrestrial Reference System (ITRS), which today are most often used...
The Mediterranean Sea has always been of economic and ecological importance to its surrounding countries. A better understanding of its currents is necessary for the management of fishery resources, potential pollution, and maritime security. Currents can be derived from the Mean Dynamic sea surface Topography (MDT), which can be estimated by subtr...
Spatial data used in Croatia are often still referred to the historical local geodetic datum, Croatian State Coordinate System, HDKS (in Croatian: Hrvatski državni koordinatni sustav). Therefore, coordinate transformation from HDKS to the official Croatian terrestrial reference system 1996, HTRS96 (in Croatian: Hrvatski terestrički referentni susta...
Some of the most commonly used geographic data in geosciences are global digital elevation models (GDEM). Their most significant feature is the global availability in high resolutions. Currently, the two most used models are made from the data of satellite mission Shuttle Radar Topography Mission (SRTM) and the Advanced Spaceborne Thermal Emission...
Accuracy assessment of digital elevation models (DEMs) plays an important role in facing their use in geoscience applications. This study investigates the vertical accuracy of most recently published versions of global DEMs over Croatia: 1 arc-minute global relief model (ETOPO1), Global 30 Arc-Second Elevation (GTOPO30), SRTM30+, Global Multi-resol...
Geomagnetic components at Croatian repeat stations and ground survey sites, as well as European observatories and repeat stations, were used to obtain a regional geomagnetic model over Croatia at 2009.5 epoch. Different models were derived, depending on input data, and the modelling techniques were Adjusted Spherical Harmonic Analysis and Spherical...
Geomagnetic components at Croatian repeat stations and ground survey sites, as well as European observatories and repeat stations, were used to obtain a regional geomagnetic model over Croatia at 2009.5 epoch. Different models were derived, depending on input data, and the modelling techniques were Adjusted Spherical Harmonic Analysis and Spherical...
From 2004-2010 geomagnetic, normal and anomalous field on secular points for the declination, inclination and total intensity was presented. A comparison between the annual changes of reduced values of the geomagnetic field, normal field and IGRF-11 model was made. For the same period anomalies and annual changes of the anomalies of the geomagnetic...
Users of digital elevation models must be aware of their main characteristics in order to judge better their suitability for a specific application. In this study, a comparison and evaluation of the characteristics of seven publicly available global digital elevation models were made for territory of the Republic of Croatia. The models chosen were:...
U radu će biti prikazan utjecaj ubrzanja sile teže na geometrijski nivelman, uz poseban osvrt na usporedbu normalnih-ortometrijskih visina dobivenih CROPOS VPPS servisom i ortometrijskih visina dobivenih izjednačenjem nivelmanskih mjerenja u realnom polju ubrzanja sile teže. Testiranje je obavljeno na nivelmanskom vlaku koji je uspostavljen na podr...
Određivanje položaja korištenjem CROPOS sustava na području Republike Hrvatske ograničeno je teritorijalnom pokrivenošću signalom mobilnih operatera. Uvođenjem tehnologija za augmentaciju globalnih navigacijskih sustava poboljšava se točnost pozicioniranja te povećava dostupnost i primjenjivost uređaja za globalno pozicioniranje. Trimble xFill sust...
Natura 2000 is the European ecological network established to protect important habitat areas and to maintain the biodiversity of the European Union. The network consists of the Special Protection Areas (SPA) selected in accordance with the directive on the Protection of Birds, and the Special Areas of Conservation (SAC) selected in accordance with...
The analysis of the night-time magnetic declination D and magnetic total intensity F observations at the POKUpsko (POKU) repeat station as well as the comparison with simultaneous Tihany (THY) observatory (Hungary) data have been presented. Generally, the geomagnetic field is less disturbed during the night-time when smaller ranges and scatters are...
The chapter gives an overview of the results of the study of the normal annual changes appropriate for the reduction of the reduced surveys of the Basic Geomagnetic Network of the Republic of Croatia to the central epoch 2009.5, which can also be used for a simple linear forward extrapolation. The reduction of the data of the neighbouring countries...
While modeling gravitational field of the Earth topographic effects are partly reduced by using topo-isostatic models. In this paper mathematical and physical background is presented as well as concrete results of testing Airy-Heiskanen (A-H) topo-isostatic compensation model. Modern studies have proven that, especially in coastal areas, A-H model...
Moderna geodetska istraživanja uklju čuju široki spektar svemirskih i terestričkih tehnika koja pridonose znanju o krutoj Zemlji, atmosferi i oceanima. U protekla dva desetljeća u sklopu IAG-a razvijali su se servisi u svrhu globalne koordinacije geodetskih aktivnosti te za osiguranje visoko-točnih i pouzdanih geodetskih proizvoda. Razumijevanje pr...
Na geodetskoj točki Kalibracijske baze Geodetskog fakulteta izvršena su GPS mjerenja, GNSS RTK metodom. Mjerenja su vršena u razdoblju od 8-17h (uobičajeno radno vrijeme geodeta na terenu) sa svrhom dobivanja koordinata uz pomoć kojih se vršila analiza točnosti CROPOS sustava. Izvršenim izjednačenjem, numeričkom i grafičkom analizom dobiveni su sta...
