TY  - CONF
AU  - Petković, Dušan
AU  - Grekulović, Sanja
AU  - Todorović Drakul, Miljana
AU  - Odalović, Oleg
PY  - 2023
UR  - https://geoscira.wixsite.com/2023
UR  - https://grafar.grf.bg.ac.rs/handle/123456789/3240
AB  - Since the last few decades of the 20th and the beginning of civilian application of NAVigation Satellite Timing And Ranging Global Positioning System (NAVSTAR GPS) established by the United States Department of Defense, satellite positioning is the most widespread technology for position determination on any place in the Earth's surface (Hofmann-Wellenhof et al., 2008). Besides positioning, a Global Navigation Satellite Systems (GNSS; a common name for all operational navigation systems worldwide) technology is used for other research applications such as atmospheric parameter estimation, i.e., ionospheric determination (Seeber et al., 2003). This paper presents the possibility of the GNSS technology as a tool for determining ionospheric models by the Bernese GNSS Software (Dach et al., 2015). Bernese supports three types of models to represent the ionosphere: local models based on Taylor series expansions, and station-specific and global (or regional) models based on spherical harmonic expansions (Schaer, 1999). Mentioned Ionospheric models (also called Ionospheric maps) can be produced in Bernese ION format or as a common data-exchange IONosphere EXchange (IONEX) format (Schaer et al., 1998). Based on these formats, it is possible to determine the quantity that characterizes the current state of the ionosphere, the so-called Total Electron Content (TEC).
PB  - Faculty of Civil Engineering, University of Belgrade
PB  - Institute of Physics Belgrade, University of Belgrade
C3  - International Conference on Recent Trends in Geoscience Research and Applications, Belgrade, October 23–27, 2023
T1  - Determination of ionospheric models using global navigational satellite systems and Bernese GNSS software
SP  - 90
UR  - https://hdl.handle.net/21.15107/rcub_grafar_3240
ER  - 

@conference{
author = "Petković, Dušan and Grekulović, Sanja and Todorović Drakul, Miljana and Odalović, Oleg",
year = "2023",
abstract = "Since the last few decades of the 20th and the beginning of civilian application of NAVigation Satellite Timing And Ranging Global Positioning System (NAVSTAR GPS) established by the United States Department of Defense, satellite positioning is the most widespread technology for position determination on any place in the Earth's surface (Hofmann-Wellenhof et al., 2008). Besides positioning, a Global Navigation Satellite Systems (GNSS; a common name for all operational navigation systems worldwide) technology is used for other research applications such as atmospheric parameter estimation, i.e., ionospheric determination (Seeber et al., 2003). This paper presents the possibility of the GNSS technology as a tool for determining ionospheric models by the Bernese GNSS Software (Dach et al., 2015). Bernese supports three types of models to represent the ionosphere: local models based on Taylor series expansions, and station-specific and global (or regional) models based on spherical harmonic expansions (Schaer, 1999). Mentioned Ionospheric models (also called Ionospheric maps) can be produced in Bernese ION format or as a common data-exchange IONosphere EXchange (IONEX) format (Schaer et al., 1998). Based on these formats, it is possible to determine the quantity that characterizes the current state of the ionosphere, the so-called Total Electron Content (TEC).",
publisher = "Faculty of Civil Engineering, University of Belgrade, Institute of Physics Belgrade, University of Belgrade",
journal = "International Conference on Recent Trends in Geoscience Research and Applications, Belgrade, October 23–27, 2023",
title = "Determination of ionospheric models using global navigational satellite systems and Bernese GNSS software",
pages = "90",
url = "https://hdl.handle.net/21.15107/rcub_grafar_3240"
}

Petković, D., Grekulović, S., Todorović Drakul, M.,& Odalović, O.. (2023). Determination of ionospheric models using global navigational satellite systems and Bernese GNSS software. in International Conference on Recent Trends in Geoscience Research and Applications, Belgrade, October 23–27, 2023
Faculty of Civil Engineering, University of Belgrade., 90.
https://hdl.handle.net/21.15107/rcub_grafar_3240

Petković D, Grekulović S, Todorović Drakul M, Odalović O. Determination of ionospheric models using global navigational satellite systems and Bernese GNSS software. in International Conference on Recent Trends in Geoscience Research and Applications, Belgrade, October 23–27, 2023. 2023;:90.
https://hdl.handle.net/21.15107/rcub_grafar_3240 .

Petković, Dušan, Grekulović, Sanja, Todorović Drakul, Miljana, Odalović, Oleg, "Determination of ionospheric models using global navigational satellite systems and Bernese GNSS software" in International Conference on Recent Trends in Geoscience Research and Applications, Belgrade, October 23–27, 2023 (2023):90,
https://hdl.handle.net/21.15107/rcub_grafar_3240 .

TY  - CONF
AU  - Odalović, Oleg
AU  - Petković, Dušan
AU  - Grekulović, Sanja
AU  - Todorović-Drakul, Miljana
PY  - 2022
UR  - http://www.drustvometrologa.org/radovi2022.php
UR  - https://grafar.grf.bg.ac.rs/handle/123456789/3044
AB  - Постоје четири у потпуности успостављена Глобална навигациона сателитска система (ГНСС): амерички GPS NAVSTAR, руски GLONASS, кинески BEIDOU (COMPASS) и европски GALILEO. Њиховом применом успешно се успостављају терестрички референтни системи широм планете. У овом раду приказан је поступак успостављања теренске базе за еталонирање мерила дужине применом технологије ГНСС-а. На релативно кратком растојању дефинисане су крајње тачке теренске базе чије су координате одређене на основу ГНСС опажања. Одређена је мерна несигурност дефинисане базе и извршено је поређење добијених резултата са вредностима добијеним класичним геодетским методама.
AB  - There are four fully operational Global Navigation Satellite Systems (GNSS): United States GPS NAVSTAR, Russian GLONASS, Chine’s BEIDOU (COMPASS), and European GALILEO. With their application, reference systems around the planet were established. This paper presents a procedure for establishing a field base for calibrating length measurement equipment using GNSS. A field base is defined as a short distance determined by its endpoints using GNSS technology. The measurement uncertainty was calculated for the defined base, and the results were compared with the values obtained using traditional geodetic methods.
PB  - Друштво метролога
C3  - Конгрес метролога 2022
T1  - Одређивање мерне несигурности резултата мерења просторног растојања применом глобалних навигационих сателитских система
T1  - Determination of spatial distance measurement uncertainty using global navigation satellite systems
UR  - https://hdl.handle.net/21.15107/rcub_grafar_3044
ER  - 

@conference{
author = "Odalović, Oleg and Petković, Dušan and Grekulović, Sanja and Todorović-Drakul, Miljana",
year = "2022",
abstract = "Постоје четири у потпуности успостављена Глобална навигациона сателитска система (ГНСС): амерички GPS NAVSTAR, руски GLONASS, кинески BEIDOU (COMPASS) и европски GALILEO. Њиховом применом успешно се успостављају терестрички референтни системи широм планете. У овом раду приказан је поступак успостављања теренске базе за еталонирање мерила дужине применом технологије ГНСС-а. На релативно кратком растојању дефинисане су крајње тачке теренске базе чије су координате одређене на основу ГНСС опажања. Одређена је мерна несигурност дефинисане базе и извршено је поређење добијених резултата са вредностима добијеним класичним геодетским методама., There are four fully operational Global Navigation Satellite Systems (GNSS): United States GPS NAVSTAR, Russian GLONASS, Chine’s BEIDOU (COMPASS), and European GALILEO. With their application, reference systems around the planet were established. This paper presents a procedure for establishing a field base for calibrating length measurement equipment using GNSS. A field base is defined as a short distance determined by its endpoints using GNSS technology. The measurement uncertainty was calculated for the defined base, and the results were compared with the values obtained using traditional geodetic methods.",
publisher = "Друштво метролога",
journal = "Конгрес метролога 2022",
title = "Одређивање мерне несигурности резултата мерења просторног растојања применом глобалних навигационих сателитских система, Determination of spatial distance measurement uncertainty using global navigation satellite systems",
url = "https://hdl.handle.net/21.15107/rcub_grafar_3044"
}

Odalović, O., Petković, D., Grekulović, S.,& Todorović-Drakul, M.. (2022). Одређивање мерне несигурности резултата мерења просторног растојања применом глобалних навигационих сателитских система. in Конгрес метролога 2022
Друштво метролога..
https://hdl.handle.net/21.15107/rcub_grafar_3044

Odalović O, Petković D, Grekulović S, Todorović-Drakul M. Одређивање мерне несигурности резултата мерења просторног растојања применом глобалних навигационих сателитских система. in Конгрес метролога 2022. 2022;.
https://hdl.handle.net/21.15107/rcub_grafar_3044 .

Odalović, Oleg, Petković, Dušan, Grekulović, Sanja, Todorović-Drakul, Miljana, "Одређивање мерне несигурности резултата мерења просторног растојања применом глобалних навигационих сателитских система" in Конгрес метролога 2022 (2022),
https://hdl.handle.net/21.15107/rcub_grafar_3044 .

TY  - CONF
AU  - Odalović, Oleg
AU  - Grekulović, Sanja
AU  - Todorović Drakul, Miljana
AU  - Petković, Dušan
PY  - 2022
UR  - https://epslibrary.at/sgem_jresearch_publication_view.php?page=view&editid1=8490&
UR  - https://grafar.grf.bg.ac.rs/handle/123456789/3036
AB  - The new network of permanent GNSS (Global Navigation Satellite System) stations should be established by the end of this year. At the moment, 18 permanent stations are already established. All stations coordinates must be determined following the conditions dictated by the Republic Geodetic Authority of Serbia, i.e., the Rule Book for establishing the GNSS permanent stations network. The coordinates of stations, the final solution, must be calculated from three consecutive uninterrupted daily sessions as a combined solution of all three days. The essential condition that must be fulfilled is the daily repeatability of the coordinates of the points for the three daily solutions on the level of 10 mm in the horizontal direction and 15 mm in the vertical direction. In other words, GNSS coordinates of the permanent station can be treated as calculated and adopted as final if the differences between coordinates of the daily solution and final solution do not exceed 10 mm in the horizontal direction and 15 mm in the vertical direction. In this research, preliminary calculations of coordinates repeatability are checked using Bernese GNSS Software Version 5.2 and two online RINEX processing tools, Australian AUSPOS - Online GPS Processing Service and Canadian CSRS-PPP (Canadian Spatial Reference System Precise Point Positioning).
PB  - SGEM, 51 Alexander Malinov blvd, Sofia, 1712, Bulgaria
C3  - 22nd International Multidisciplinary Scientific GeoConference SGEM 2022, Vol22, Issue 2.1
T1  - Determinations of the preliminary coordinates for the new GNSS permanent station network in Serbia
EP  - 194
IS  - 2.1
SP  - 187
VL  - 22
DO  - 10.5593/sgem2022/2.1/s09.23
ER  - 

@conference{
author = "Odalović, Oleg and Grekulović, Sanja and Todorović Drakul, Miljana and Petković, Dušan",
year = "2022",
abstract = "The new network of permanent GNSS (Global Navigation Satellite System) stations should be established by the end of this year. At the moment, 18 permanent stations are already established. All stations coordinates must be determined following the conditions dictated by the Republic Geodetic Authority of Serbia, i.e., the Rule Book for establishing the GNSS permanent stations network. The coordinates of stations, the final solution, must be calculated from three consecutive uninterrupted daily sessions as a combined solution of all three days. The essential condition that must be fulfilled is the daily repeatability of the coordinates of the points for the three daily solutions on the level of 10 mm in the horizontal direction and 15 mm in the vertical direction. In other words, GNSS coordinates of the permanent station can be treated as calculated and adopted as final if the differences between coordinates of the daily solution and final solution do not exceed 10 mm in the horizontal direction and 15 mm in the vertical direction. In this research, preliminary calculations of coordinates repeatability are checked using Bernese GNSS Software Version 5.2 and two online RINEX processing tools, Australian AUSPOS - Online GPS Processing Service and Canadian CSRS-PPP (Canadian Spatial Reference System Precise Point Positioning).",
publisher = "SGEM, 51 Alexander Malinov blvd, Sofia, 1712, Bulgaria",
journal = "22nd International Multidisciplinary Scientific GeoConference SGEM 2022, Vol22, Issue 2.1",
title = "Determinations of the preliminary coordinates for the new GNSS permanent station network in Serbia",
pages = "194-187",
number = "2.1",
volume = "22",
doi = "10.5593/sgem2022/2.1/s09.23"
}

Odalović, O., Grekulović, S., Todorović Drakul, M.,& Petković, D.. (2022). Determinations of the preliminary coordinates for the new GNSS permanent station network in Serbia. in 22nd International Multidisciplinary Scientific GeoConference SGEM 2022, Vol22, Issue 2.1
SGEM, 51 Alexander Malinov blvd, Sofia, 1712, Bulgaria., 22(2.1), 187-194.
https://doi.org/10.5593/sgem2022/2.1/s09.23

Odalović O, Grekulović S, Todorović Drakul M, Petković D. Determinations of the preliminary coordinates for the new GNSS permanent station network in Serbia. in 22nd International Multidisciplinary Scientific GeoConference SGEM 2022, Vol22, Issue 2.1. 2022;22(2.1):187-194.
doi:10.5593/sgem2022/2.1/s09.23 .

Odalović, Oleg, Grekulović, Sanja, Todorović Drakul, Miljana, Petković, Dušan, "Determinations of the preliminary coordinates for the new GNSS permanent station network in Serbia" in 22nd International Multidisciplinary Scientific GeoConference SGEM 2022, Vol22, Issue 2.1, 22, no. 2.1 (2022):187-194,
https://doi.org/10.5593/sgem2022/2.1/s09.23 . .

TY  - CONF
AU  - Todorović-Drakul, Miljana
AU  - Grekulović, Sanja
AU  - Odalovic, Oleg
AU  - Petković, Dušan
PY  - 2022
UR  - https://grafar.grf.bg.ac.rs/handle/123456789/2689
AB  - In this paper, a comparative study of the total vertical electron content (VTEC) calculated using the IRI-2016 and NeQuick2 models were performed. The research was done for the days of maximum solar activity in 2019, with data from seven IGS GNNS stations in the region of the Balkan Peninsula. The results show that both models agree quite well with the observed VTEC values obtained from GNSS measurements at all stations, although with some offset observed during several days at different times. The IRI-2016 model performed better than the NeQuick2 model most of the days and stations for which the NeQuick model overestimates the GNSS VTEC. The results show that the Neckick model gives better quality values in some cases, but for isolated instances.
AB  - У овом раду вршена је упоредна студија вредности укупног вертикалног садржаја електрона (VTEC) срачунатог коришћењем IRI-2016 и NeQuick2 модела. Истраживање је рађено за дане максималне соларне активности током 2019. године са подацима са седам ИГС ГННС станица у региону Балканског полуострва. Резултати показују да се оба модела прилично добро слажу са вредностима VTEC добијеним из ГНСС мерења на свим станицама, иако са извесним неслагањима уоченим током неколико дана у различитим временским интервалима. Модел IRI-2016 је показао боље перфрормансе од NeQuick2 модела за већину тестираних периода и већину станица за које NeQuick2 прецењује ГНСС VTEC vrednosti. Резултати показују да NeQuick2 модел даје вредности бољег квалитета, али само у ограниченом броју случајева.
PB  - University of Banja Luka, Faculty of Architecture, Civil Engineering and Geodesy
C3  - INTERNATIONAL CONFERENCE ON CONTEMPORARY THEORY AND PRACTICE IN CONSTRUCTION XV
T1  - Comparison of IRI-2016 and NEQUICK models of the ionosphere over the
Balkan Peninsula during the year 2019
T1  - Поређење IRI-2016 и NEQUICK модела јонофере изнад Балканског полуострва током 2019. године
EP  - 293
SP  - 283
DO  - 10.7251/STP2215283T
ER  - 

@conference{
author = "Todorović-Drakul, Miljana and Grekulović, Sanja and Odalovic, Oleg and Petković, Dušan",
year = "2022",
abstract = "In this paper, a comparative study of the total vertical electron content (VTEC) calculated using the IRI-2016 and NeQuick2 models were performed. The research was done for the days of maximum solar activity in 2019, with data from seven IGS GNNS stations in the region of the Balkan Peninsula. The results show that both models agree quite well with the observed VTEC values obtained from GNSS measurements at all stations, although with some offset observed during several days at different times. The IRI-2016 model performed better than the NeQuick2 model most of the days and stations for which the NeQuick model overestimates the GNSS VTEC. The results show that the Neckick model gives better quality values in some cases, but for isolated instances., У овом раду вршена је упоредна студија вредности укупног вертикалног садржаја електрона (VTEC) срачунатог коришћењем IRI-2016 и NeQuick2 модела. Истраживање је рађено за дане максималне соларне активности током 2019. године са подацима са седам ИГС ГННС станица у региону Балканског полуострва. Резултати показују да се оба модела прилично добро слажу са вредностима VTEC добијеним из ГНСС мерења на свим станицама, иако са извесним неслагањима уоченим током неколико дана у различитим временским интервалима. Модел IRI-2016 је показао боље перфрормансе од NeQuick2 модела за већину тестираних периода и већину станица за које NeQuick2 прецењује ГНСС VTEC vrednosti. Резултати показују да NeQuick2 модел даје вредности бољег квалитета, али само у ограниченом броју случајева.",
publisher = "University of Banja Luka, Faculty of Architecture, Civil Engineering and Geodesy",
journal = "INTERNATIONAL CONFERENCE ON CONTEMPORARY THEORY AND PRACTICE IN CONSTRUCTION XV",
title = "Comparison of IRI-2016 and NEQUICK models of the ionosphere over the
Balkan Peninsula during the year 2019, Поређење IRI-2016 и NEQUICK модела јонофере изнад Балканског полуострва током 2019. године",
pages = "293-283",
doi = "10.7251/STP2215283T"
}

Todorović-Drakul, M., Grekulović, S., Odalovic, O.,& Petković, D.. (2022). Comparison of IRI-2016 and NEQUICK models of the ionosphere over the
Balkan Peninsula during the year 2019. in INTERNATIONAL CONFERENCE ON CONTEMPORARY THEORY AND PRACTICE IN CONSTRUCTION XV
University of Banja Luka, Faculty of Architecture, Civil Engineering and Geodesy., 283-293.
https://doi.org/10.7251/STP2215283T

Todorović-Drakul M, Grekulović S, Odalovic O, Petković D. Comparison of IRI-2016 and NEQUICK models of the ionosphere over the
Balkan Peninsula during the year 2019. in INTERNATIONAL CONFERENCE ON CONTEMPORARY THEORY AND PRACTICE IN CONSTRUCTION XV. 2022;:283-293.
doi:10.7251/STP2215283T .

Todorović-Drakul, Miljana, Grekulović, Sanja, Odalovic, Oleg, Petković, Dušan, "Comparison of IRI-2016 and NEQUICK models of the ionosphere over the
Balkan Peninsula during the year 2019" in INTERNATIONAL CONFERENCE ON CONTEMPORARY THEORY AND PRACTICE IN CONSTRUCTION XV (2022):283-293,
https://doi.org/10.7251/STP2215283T . .

TY  - CONF
AU  - Grekulović, Sanja
AU  - Odalović, Oleg
AU  - Todorović Drakul, Miljana
AU  - Petković, Dušan
PY  - 2022
UR  - https://epslibrary.at/sgem_jresearch_publication_view.php?page=view&editid1=8492&
UR  - https://grafar.grf.bg.ac.rs/handle/123456789/3037
AB  - In 2004, a digital terrain model (DTM) was created in Serbia. It was obtained by vectorizing isohypses on topographic maps with a scale of 1: 25000. The resolution of the digital model of Serbia is 30 m, and the vertical accuracy, as the authors claim, is 10
m. From December 2021, the global model FABDEM (Forest And Buildings removed Copernicus DEM) is available to the public. It was created based on the data of the Copernicus GLO30 model so that data on forests and buildings were removed from it. Important features of the global model are its horizontal resolution of 30 m and vertical accuracy of less than 5 m. This paper aims to assess the vertical accuracy of the global FABDEM model and analyze the differences between the global FABDEM and DTM  in the territory of the Republic of Serbia. Vertical accuracy and analysis of the two models were assessed by comparing the heights derived from FABDEM and DTM with the heights of the independent set of points of the gravimetric survey of Serbia (GSS). The heights of the GSS points were determined using classical geodetic methods, and they are relatively uniformly distributed on the territory of the Republic of Serbia. A short description of mentioned comparison is presented in this paper. Statistical analysis results that compare terrestrial heights with heights derived from DTMs show minor differences between the two data sets.
PB  - SGEM, 51 Alexander Malinov blvd, Sofia, 1712, Bulgaria
C3  - 22nd International Multidisciplinary Scientific GeoConference SGEM 2022, Vol22, Issue 2.1
T1  - Estimation of vertical accuracy of digital terrain model FABDEM on the territory of the republic of Serbia
EP  - 210
IS  - 2.1
SP  - 203
VL  - 22
DO  - 10.5593/sgem2022/2.1/s09.25
ER  - 

@conference{
author = "Grekulović, Sanja and Odalović, Oleg and Todorović Drakul, Miljana and Petković, Dušan",
year = "2022",
abstract = "In 2004, a digital terrain model (DTM) was created in Serbia. It was obtained by vectorizing isohypses on topographic maps with a scale of 1: 25000. The resolution of the digital model of Serbia is 30 m, and the vertical accuracy, as the authors claim, is 10
m. From December 2021, the global model FABDEM (Forest And Buildings removed Copernicus DEM) is available to the public. It was created based on the data of the Copernicus GLO30 model so that data on forests and buildings were removed from it. Important features of the global model are its horizontal resolution of 30 m and vertical accuracy of less than 5 m. This paper aims to assess the vertical accuracy of the global FABDEM model and analyze the differences between the global FABDEM and DTM  in the territory of the Republic of Serbia. Vertical accuracy and analysis of the two models were assessed by comparing the heights derived from FABDEM and DTM with the heights of the independent set of points of the gravimetric survey of Serbia (GSS). The heights of the GSS points were determined using classical geodetic methods, and they are relatively uniformly distributed on the territory of the Republic of Serbia. A short description of mentioned comparison is presented in this paper. Statistical analysis results that compare terrestrial heights with heights derived from DTMs show minor differences between the two data sets.",
publisher = "SGEM, 51 Alexander Malinov blvd, Sofia, 1712, Bulgaria",
journal = "22nd International Multidisciplinary Scientific GeoConference SGEM 2022, Vol22, Issue 2.1",
title = "Estimation of vertical accuracy of digital terrain model FABDEM on the territory of the republic of Serbia",
pages = "210-203",
number = "2.1",
volume = "22",
doi = "10.5593/sgem2022/2.1/s09.25"
}

Grekulović, S., Odalović, O., Todorović Drakul, M.,& Petković, D.. (2022). Estimation of vertical accuracy of digital terrain model FABDEM on the territory of the republic of Serbia. in 22nd International Multidisciplinary Scientific GeoConference SGEM 2022, Vol22, Issue 2.1
SGEM, 51 Alexander Malinov blvd, Sofia, 1712, Bulgaria., 22(2.1), 203-210.
https://doi.org/10.5593/sgem2022/2.1/s09.25

Grekulović S, Odalović O, Todorović Drakul M, Petković D. Estimation of vertical accuracy of digital terrain model FABDEM on the territory of the republic of Serbia. in 22nd International Multidisciplinary Scientific GeoConference SGEM 2022, Vol22, Issue 2.1. 2022;22(2.1):203-210.
doi:10.5593/sgem2022/2.1/s09.25 .

Grekulović, Sanja, Odalović, Oleg, Todorović Drakul, Miljana, Petković, Dušan, "Estimation of vertical accuracy of digital terrain model FABDEM on the territory of the republic of Serbia" in 22nd International Multidisciplinary Scientific GeoConference SGEM 2022, Vol22, Issue 2.1, 22, no. 2.1 (2022):203-210,
https://doi.org/10.5593/sgem2022/2.1/s09.25 . .

TY  - CONF
AU  - Grekulović, Sanja
AU  - Paunković, Nikola
AU  - Petković, Dušan
AU  - Todorović-Drakul, Miljana
AU  - Ilijević, Slavica
PY  - 2022
UR  - https://grafar.grf.bg.ac.rs/handle/123456789/2664
AB  - Antenna phase center of GNSS receiver is the point where the signals transmitted from satellites are collected. However, this point is not necessarily the physical center of antenna (geometric center of antenna). In general, for most applications of GNSS, users consider the phase center to be a fixed point. But this point has its variation based on the direction of the radio signal source. Direction of incoming signal from satellite is definite with azimuth and elevation angle. Moreover, antenna phase centre is not only angle dependant, it also depends on the signal frequency. Variation of antenna phase center with the azimuth and elevation angle of incoming signal from satellite and with the frequency of incoming signal is used to called phase center variation. In geodesy (also as well in other areas), there are applications with high accuracy demands in terms of point precision (millimeter accuracy) or some other quantities. For those applications, users must consider the influence of phase center variation. With the appropriate settings, it is possible to estimate the variation of the phase center. The mean phase center and its variation can then be used in the software for GNSS data processing. In this paper, field procedure for estimation of antenna phase center is presented. On stable ground with a clear sky without any obstacles or sources of radiation nearby, a test field has been established. The test field contains two nearby points. Those points have been occupied in four sessions. Based on collected data, mean phase center has been determined, as well as the phase center differences from all four sessions and for each Global Navigation Satellite System independent (NAVSTAR GPS, GLONASS, GALILEO and BAIDOU). In addition, the expanded uncertainty of coordinates has been calculated.
PB  - University of Montenegro, Faculty of Civil Engineering
T1  - Field procedure for estimation of antenna phase center variation with expanded measurement uncertainty calculation
UR  - https://hdl.handle.net/21.15107/rcub_grafar_2664
ER  - 

@conference{
author = "Grekulović, Sanja and Paunković, Nikola and Petković, Dušan and Todorović-Drakul, Miljana and Ilijević, Slavica",
year = "2022",
abstract = "Antenna phase center of GNSS receiver is the point where the signals transmitted from satellites are collected. However, this point is not necessarily the physical center of antenna (geometric center of antenna). In general, for most applications of GNSS, users consider the phase center to be a fixed point. But this point has its variation based on the direction of the radio signal source. Direction of incoming signal from satellite is definite with azimuth and elevation angle. Moreover, antenna phase centre is not only angle dependant, it also depends on the signal frequency. Variation of antenna phase center with the azimuth and elevation angle of incoming signal from satellite and with the frequency of incoming signal is used to called phase center variation. In geodesy (also as well in other areas), there are applications with high accuracy demands in terms of point precision (millimeter accuracy) or some other quantities. For those applications, users must consider the influence of phase center variation. With the appropriate settings, it is possible to estimate the variation of the phase center. The mean phase center and its variation can then be used in the software for GNSS data processing. In this paper, field procedure for estimation of antenna phase center is presented. On stable ground with a clear sky without any obstacles or sources of radiation nearby, a test field has been established. The test field contains two nearby points. Those points have been occupied in four sessions. Based on collected data, mean phase center has been determined, as well as the phase center differences from all four sessions and for each Global Navigation Satellite System independent (NAVSTAR GPS, GLONASS, GALILEO and BAIDOU). In addition, the expanded uncertainty of coordinates has been calculated.",
publisher = "University of Montenegro, Faculty of Civil Engineering",
title = "Field procedure for estimation of antenna phase center variation with expanded measurement uncertainty calculation",
url = "https://hdl.handle.net/21.15107/rcub_grafar_2664"
}

Grekulović, S., Paunković, N., Petković, D., Todorović-Drakul, M.,& Ilijević, S.. (2022). Field procedure for estimation of antenna phase center variation with expanded measurement uncertainty calculation. 
University of Montenegro, Faculty of Civil Engineering..
https://hdl.handle.net/21.15107/rcub_grafar_2664

Grekulović S, Paunković N, Petković D, Todorović-Drakul M, Ilijević S. Field procedure for estimation of antenna phase center variation with expanded measurement uncertainty calculation. 2022;.
https://hdl.handle.net/21.15107/rcub_grafar_2664 .

Grekulović, Sanja, Paunković, Nikola, Petković, Dušan, Todorović-Drakul, Miljana, Ilijević, Slavica, "Field procedure for estimation of antenna phase center variation with expanded measurement uncertainty calculation" (2022),
https://hdl.handle.net/21.15107/rcub_grafar_2664 .

TY  - JOUR
AU  - Nina, Aleksandra
AU  - Nico, Giovanni
AU  - Odalović, Oleg
AU  - Čadež, Vladimir M.
AU  - Todorović-Drakul, Miljana
AU  - Radovanović, Milan
AU  - Popović, Luka Č.
PY  - 2019
UR  - https://grafar.grf.bg.ac.rs/handle/123456789/1760
AB  - We investigate the influence of the perturbed (by a solar X-ray flare) ionospheric D-region on the GNSS and SAR signals. We calculate a signal delay in the D-region based on the low ionospheric monitoring by very low frequency (VLF) radio waves. Results show that the ionospheric delay in the perturbed D-region can be important and, therefore, should be taken into account in modeling the ionospheric influence on the GNSS and SAR signal propagation and in calculations relevant for space geodesy. This conclusion is significant because numerous existing models ignore the
impact of this ionospheric part on the GNSS and SAR signals due to its small electron density which is true only in quiet conditions and can result in significant errors in space geodesy during intensive ionospheric disturbances.
PB  - IEEE (Institute of Electrical and Electronics Engineers)
T2  - IEEE Geoscience and Remote Sensing Letters
T1  - GNSS and SAR Signal Delay in Perturbed Ionospheric D-Region During Solar X-Ray Flares
DO  - 10.1109/LGRS.2019.2941643
ER  - 

@article{
author = "Nina, Aleksandra and Nico, Giovanni and Odalović, Oleg and Čadež, Vladimir M. and Todorović-Drakul, Miljana and Radovanović, Milan and Popović, Luka Č.",
year = "2019",
abstract = "We investigate the influence of the perturbed (by a solar X-ray flare) ionospheric D-region on the GNSS and SAR signals. We calculate a signal delay in the D-region based on the low ionospheric monitoring by very low frequency (VLF) radio waves. Results show that the ionospheric delay in the perturbed D-region can be important and, therefore, should be taken into account in modeling the ionospheric influence on the GNSS and SAR signal propagation and in calculations relevant for space geodesy. This conclusion is significant because numerous existing models ignore the
impact of this ionospheric part on the GNSS and SAR signals due to its small electron density which is true only in quiet conditions and can result in significant errors in space geodesy during intensive ionospheric disturbances.",
publisher = "IEEE (Institute of Electrical and Electronics Engineers)",
journal = "IEEE Geoscience and Remote Sensing Letters",
title = "GNSS and SAR Signal Delay in Perturbed Ionospheric D-Region During Solar X-Ray Flares",
doi = "10.1109/LGRS.2019.2941643"
}

Nina, A., Nico, G., Odalović, O., Čadež, V. M., Todorović-Drakul, M., Radovanović, M.,& Popović, L. Č.. (2019). GNSS and SAR Signal Delay in Perturbed Ionospheric D-Region During Solar X-Ray Flares. in IEEE Geoscience and Remote Sensing Letters
IEEE (Institute of Electrical and Electronics Engineers)..
https://doi.org/10.1109/LGRS.2019.2941643

Nina A, Nico G, Odalović O, Čadež VM, Todorović-Drakul M, Radovanović M, Popović LČ. GNSS and SAR Signal Delay in Perturbed Ionospheric D-Region During Solar X-Ray Flares. in IEEE Geoscience and Remote Sensing Letters. 2019;.
doi:10.1109/LGRS.2019.2941643 .

Nina, Aleksandra, Nico, Giovanni, Odalović, Oleg, Čadež, Vladimir M., Todorović-Drakul, Miljana, Radovanović, Milan, Popović, Luka Č., "GNSS and SAR Signal Delay in Perturbed Ionospheric D-Region During Solar X-Ray Flares" in IEEE Geoscience and Remote Sensing Letters (2019),
https://doi.org/10.1109/LGRS.2019.2941643 . .

TY  - JOUR
AU  - Todorović-Drakul, Miljana
AU  - Samardžić-Petrović, Mileva
AU  - Grekulović, Sanja
AU  - Odalović, Oleg
AU  - Blagojević, Dragan
PY  - 2018
UR  - https://grafar.grf.bg.ac.rs/handle/123456789/955
AB  - This paper is dedicated to modeling extreme TEC (Total Electron Content) values at the territory of Serbia. For the extreme TEC values, we consider the maximum values from the peak of the 11-year cycle of solar activity in the years 2013, 2014 and 2015 for the days of the winter and summer solstice and autumnal and vernal equinox. The average TEC values between 10 and 12 UT (Universal Time) were treated. As the basic data for all processing, we used GNSS (Global Navigation Satellite System) observation obtained by three permanent stations located in the territory of Serbia. Those data, we accept as actual, i. e. as a "true TEC values". The main objectives of this research were to examine the possibility to use two machine learning techniques: neural networks and support vector machine. In order to emphasize the quality of applied techniques, all results are adequately compared to the TEC values obtained by using International Reference Ionosphere global model. In addition, we separately analyzed the quality of techniques throughout temporal and spatial-temporal approach.
PB  - Geofizicki Zavod
T2  - Geofizika
T1  - Modelling extreme values of the total electron content: Case study of Serbia
EP  - 314
IS  - 2
SP  - 297
VL  - 34
DO  - 10.15233/gfz.2017.34.12
ER  - 

@article{
author = "Todorović-Drakul, Miljana and Samardžić-Petrović, Mileva and Grekulović, Sanja and Odalović, Oleg and Blagojević, Dragan",
year = "2018",
abstract = "This paper is dedicated to modeling extreme TEC (Total Electron Content) values at the territory of Serbia. For the extreme TEC values, we consider the maximum values from the peak of the 11-year cycle of solar activity in the years 2013, 2014 and 2015 for the days of the winter and summer solstice and autumnal and vernal equinox. The average TEC values between 10 and 12 UT (Universal Time) were treated. As the basic data for all processing, we used GNSS (Global Navigation Satellite System) observation obtained by three permanent stations located in the territory of Serbia. Those data, we accept as actual, i. e. as a "true TEC values". The main objectives of this research were to examine the possibility to use two machine learning techniques: neural networks and support vector machine. In order to emphasize the quality of applied techniques, all results are adequately compared to the TEC values obtained by using International Reference Ionosphere global model. In addition, we separately analyzed the quality of techniques throughout temporal and spatial-temporal approach.",
publisher = "Geofizicki Zavod",
journal = "Geofizika",
title = "Modelling extreme values of the total electron content: Case study of Serbia",
pages = "314-297",
number = "2",
volume = "34",
doi = "10.15233/gfz.2017.34.12"
}

Todorović-Drakul, M., Samardžić-Petrović, M., Grekulović, S., Odalović, O.,& Blagojević, D.. (2018). Modelling extreme values of the total electron content: Case study of Serbia. in Geofizika
Geofizicki Zavod., 34(2), 297-314.
https://doi.org/10.15233/gfz.2017.34.12

Todorović-Drakul M, Samardžić-Petrović M, Grekulović S, Odalović O, Blagojević D. Modelling extreme values of the total electron content: Case study of Serbia. in Geofizika. 2018;34(2):297-314.
doi:10.15233/gfz.2017.34.12 .

Todorović-Drakul, Miljana, Samardžić-Petrović, Mileva, Grekulović, Sanja, Odalović, Oleg, Blagojević, Dragan, "Modelling extreme values of the total electron content: Case study of Serbia" in Geofizika, 34, no. 2 (2018):297-314,
https://doi.org/10.15233/gfz.2017.34.12 . .

TY  - JOUR
AU  - Odalović, Oleg
AU  - Todorović-Drakul, Miljana
AU  - Grekulović, Sanja
AU  - Popović, Jovan
AU  - Joksimović, Danilo
PY  - 2018
UR  - https://grafar.grf.bg.ac.rs/handle/123456789/930
AB  - In this paper, the development of geodetic reference networks in Serbia is shown. This historical summary covers the time from the first organised work in 1855 until today. Special attention has been paid to the establishment of the modern network using Global Navigation Satellite Systems (GNSS). Within the networks established by GNSS, two last realised networks are especially distinguished. The first one is a classic spatial reference network SREF (Serbian Reference Frame) established in 2003, and the second one is a permanent stations network - AGROS (Active Geodetic Reference Network of Serbia) realised in 2006.
PB  - Taylor and Francis Ltd.
T2  - Survey Review
T1  - Chronology of the development of geodetic reference networks in Serbia
EP  - 173
IS  - 359
SP  - 163
VL  - 50
DO  - 10.1080/00396265.2016.1249998
ER  - 

@article{
author = "Odalović, Oleg and Todorović-Drakul, Miljana and Grekulović, Sanja and Popović, Jovan and Joksimović, Danilo",
year = "2018",
abstract = "In this paper, the development of geodetic reference networks in Serbia is shown. This historical summary covers the time from the first organised work in 1855 until today. Special attention has been paid to the establishment of the modern network using Global Navigation Satellite Systems (GNSS). Within the networks established by GNSS, two last realised networks are especially distinguished. The first one is a classic spatial reference network SREF (Serbian Reference Frame) established in 2003, and the second one is a permanent stations network - AGROS (Active Geodetic Reference Network of Serbia) realised in 2006.",
publisher = "Taylor and Francis Ltd.",
journal = "Survey Review",
title = "Chronology of the development of geodetic reference networks in Serbia",
pages = "173-163",
number = "359",
volume = "50",
doi = "10.1080/00396265.2016.1249998"
}

Odalović, O., Todorović-Drakul, M., Grekulović, S., Popović, J.,& Joksimović, D.. (2018). Chronology of the development of geodetic reference networks in Serbia. in Survey Review
Taylor and Francis Ltd.., 50(359), 163-173.
https://doi.org/10.1080/00396265.2016.1249998

Odalović O, Todorović-Drakul M, Grekulović S, Popović J, Joksimović D. Chronology of the development of geodetic reference networks in Serbia. in Survey Review. 2018;50(359):163-173.
doi:10.1080/00396265.2016.1249998 .

Odalović, Oleg, Todorović-Drakul, Miljana, Grekulović, Sanja, Popović, Jovan, Joksimović, Danilo, "Chronology of the development of geodetic reference networks in Serbia" in Survey Review, 50, no. 359 (2018):163-173,
https://doi.org/10.1080/00396265.2016.1249998 . .

TY  - JOUR
AU  - Odalović, Oleg
AU  - Grekulović, Sanja
AU  - Starcević, Miroslav
AU  - Nikolić, Dobrica
AU  - Todorović-Drakul, Miljana
AU  - Joksimović, Danilo
PY  - 2018
UR  - https://grafar.grf.bg.ac.rs/handle/123456789/961
AB  - This paper presents the determination of terrain correction by the means of the Digital Density Model (DDM) of topographic masses (Earth's crust mass above the geoid) for the territory of Serbia. The DDM is determined using the Digital Terrain Model (DTM) with the resolution of 30 m, basic geological map of Serbia, and a set of hypotheses on the density of the Earth's crust masses. The assumption that the general lithosphere density over the territory of Serbia ranges between 2200 kg/m(3) and 2800 kg/m(3) was adopted. Terrain correction is determined at 5765 points, with relatively uniform distribution over the territory of Serbia. The calculations had also included comparing the values obtained therein to the terrain corrections obtained when accepting the hypothesis of constant lithosphere density of 2670 kg/m(3) . Results of comparison highlight that the differences of terrain correction values ranging from -1.31 mGal to 0.73 mGal, along with 98 % of differences falling within the range of +/- 0.2 mGal.
PB  - Zvava Geodetov Slovenije
T2  - Geodetski vestnik
T1  - Terrain correction computations using digital density model of topographic masses
EP  - 97
IS  - 1
SP  - 79
VL  - 62
DO  - 10.15292/geodetski-vestnik.2018.01.79-97
ER  - 

@article{
author = "Odalović, Oleg and Grekulović, Sanja and Starcević, Miroslav and Nikolić, Dobrica and Todorović-Drakul, Miljana and Joksimović, Danilo",
year = "2018",
abstract = "This paper presents the determination of terrain correction by the means of the Digital Density Model (DDM) of topographic masses (Earth's crust mass above the geoid) for the territory of Serbia. The DDM is determined using the Digital Terrain Model (DTM) with the resolution of 30 m, basic geological map of Serbia, and a set of hypotheses on the density of the Earth's crust masses. The assumption that the general lithosphere density over the territory of Serbia ranges between 2200 kg/m(3) and 2800 kg/m(3) was adopted. Terrain correction is determined at 5765 points, with relatively uniform distribution over the territory of Serbia. The calculations had also included comparing the values obtained therein to the terrain corrections obtained when accepting the hypothesis of constant lithosphere density of 2670 kg/m(3) . Results of comparison highlight that the differences of terrain correction values ranging from -1.31 mGal to 0.73 mGal, along with 98 % of differences falling within the range of +/- 0.2 mGal.",
publisher = "Zvava Geodetov Slovenije",
journal = "Geodetski vestnik",
title = "Terrain correction computations using digital density model of topographic masses",
pages = "97-79",
number = "1",
volume = "62",
doi = "10.15292/geodetski-vestnik.2018.01.79-97"
}

Odalović, O., Grekulović, S., Starcević, M., Nikolić, D., Todorović-Drakul, M.,& Joksimović, D.. (2018). Terrain correction computations using digital density model of topographic masses. in Geodetski vestnik
Zvava Geodetov Slovenije., 62(1), 79-97.
https://doi.org/10.15292/geodetski-vestnik.2018.01.79-97

Odalović O, Grekulović S, Starcević M, Nikolić D, Todorović-Drakul M, Joksimović D. Terrain correction computations using digital density model of topographic masses. in Geodetski vestnik. 2018;62(1):79-97.
doi:10.15292/geodetski-vestnik.2018.01.79-97 .

Odalović, Oleg, Grekulović, Sanja, Starcević, Miroslav, Nikolić, Dobrica, Todorović-Drakul, Miljana, Joksimović, Danilo, "Terrain correction computations using digital density model of topographic masses" in Geodetski vestnik, 62, no. 1 (2018):79-97,
https://doi.org/10.15292/geodetski-vestnik.2018.01.79-97 . .

TY  - JOUR
AU  - Odalović, Oleg
AU  - Stanković, Marko D.
AU  - Grekulović, Sanja
AU  - Joksimović, Danilo
AU  - Todorović-Drakul, Miljana
PY  - 2018
UR  - https://grafar.grf.bg.ac.rs/handle/123456789/924
AB  - This paper presents the determination of the vertical deflection components using the Global Geopotential Model EGM2008. The components are defined in two groups of points: 4083 points are relatively correctly distributed across the territory of Serbia and 46 Laplas and geoid points defined in Serbia in the past century, from the set of institutions. All presented determinations in this paper are related to the Geodetic Reference System 1980 (GRS80), with the coordinates of all the points used to refer to the International Terrestrial Frame 1996 (ITRF96). Analysis of the results of the determination showed that the EGM2008 can be used to approximate the astrogeodetic determination with the agreement of several arc seconds.
AB  - U okviru rada prikazano je određivanje komponenti odstupanja vertikala primenom Globalnog geopotencijalnog modela EGM2008 (Earth Gravitational Model 2008). Komponente su određene u dve grupe tačaka: 4083 tačke relativno pravilno raspoređene po teritoriji Srbije i 46 Laplasovih i geoidnih tačaka koje su određene u Srbiji u prošlom veku, od stane niza institucija. Sva prikazana određivanja u okviru rada odnose se na Geodetski referentni sistem 1980 (Geodetic Reference System 1980 - GRS80), pri čemu se koordinate svih korišćenih tačaka odnose na Međunarodni referentni okvir za epohu 1996 (International Terestrial Frame 1996 - ITRF96). Analizom rezultata određivanja pokazano je da se EGM2008 može koristiti za aproksimaciju astrogeodetskih određivanja sa saglasnošću od nekoliko lučnih sekundi.
PB  - Savez inženjera i tehničara Srbije, Beograd
T2  - Tehnika
T1  - Determination of deflection of the vertical components by using global geopotential model EGM2008
T1  - Određivanje komponenti odstupanja vertikale primenom globalnog geopotencijalnog modela EGM2008
EP  - 338
IS  - 3
SP  - 333
VL  - 73
DO  - 10.5937/tehnika1803333O
ER  - 

@article{
author = "Odalović, Oleg and Stanković, Marko D. and Grekulović, Sanja and Joksimović, Danilo and Todorović-Drakul, Miljana",
year = "2018",
abstract = "This paper presents the determination of the vertical deflection components using the Global Geopotential Model EGM2008. The components are defined in two groups of points: 4083 points are relatively correctly distributed across the territory of Serbia and 46 Laplas and geoid points defined in Serbia in the past century, from the set of institutions. All presented determinations in this paper are related to the Geodetic Reference System 1980 (GRS80), with the coordinates of all the points used to refer to the International Terrestrial Frame 1996 (ITRF96). Analysis of the results of the determination showed that the EGM2008 can be used to approximate the astrogeodetic determination with the agreement of several arc seconds., U okviru rada prikazano je određivanje komponenti odstupanja vertikala primenom Globalnog geopotencijalnog modela EGM2008 (Earth Gravitational Model 2008). Komponente su određene u dve grupe tačaka: 4083 tačke relativno pravilno raspoređene po teritoriji Srbije i 46 Laplasovih i geoidnih tačaka koje su određene u Srbiji u prošlom veku, od stane niza institucija. Sva prikazana određivanja u okviru rada odnose se na Geodetski referentni sistem 1980 (Geodetic Reference System 1980 - GRS80), pri čemu se koordinate svih korišćenih tačaka odnose na Međunarodni referentni okvir za epohu 1996 (International Terestrial Frame 1996 - ITRF96). Analizom rezultata određivanja pokazano je da se EGM2008 može koristiti za aproksimaciju astrogeodetskih određivanja sa saglasnošću od nekoliko lučnih sekundi.",
publisher = "Savez inženjera i tehničara Srbije, Beograd",
journal = "Tehnika",
title = "Determination of deflection of the vertical components by using global geopotential model EGM2008, Određivanje komponenti odstupanja vertikale primenom globalnog geopotencijalnog modela EGM2008",
pages = "338-333",
number = "3",
volume = "73",
doi = "10.5937/tehnika1803333O"
}

Odalović, O., Stanković, M. D., Grekulović, S., Joksimović, D.,& Todorović-Drakul, M.. (2018). Determination of deflection of the vertical components by using global geopotential model EGM2008. in Tehnika
Savez inženjera i tehničara Srbije, Beograd., 73(3), 333-338.
https://doi.org/10.5937/tehnika1803333O

Odalović O, Stanković MD, Grekulović S, Joksimović D, Todorović-Drakul M. Determination of deflection of the vertical components by using global geopotential model EGM2008. in Tehnika. 2018;73(3):333-338.
doi:10.5937/tehnika1803333O .

Odalović, Oleg, Stanković, Marko D., Grekulović, Sanja, Joksimović, Danilo, Todorović-Drakul, Miljana, "Determination of deflection of the vertical components by using global geopotential model EGM2008" in Tehnika, 73, no. 3 (2018):333-338,
https://doi.org/10.5937/tehnika1803333O . .

TY  - JOUR
AU  - Popović, Jovan
AU  - Aleksić, Ivan R.
AU  - Božić, Branko
AU  - Milovanović, Branko
AU  - Todorović-Drakul, Miljana
PY  - 2017
UR  - https://grafar.grf.bg.ac.rs/handle/123456789/841
AB  - The paper presents the adaptation (fitting) of a set of points, with an estimated two-dimensional positions, to the straight line model of the by the application of the Weighted Total Least Squares, WTLS. The traditional method to solve this problem by using an iterative algorithm of the conditional adjustment with the parameters (Gauss-Helmert's model) is also shown. In the example of testing the straightness of the rail of the crane, a comparison of the efficiency of the two algorithms is performed by means of result of parameter estimation and to the number of required iterations to final solution.
AB  - U radu je prikazano adaptiranje (fitovanje) skupa tačaka, sa ocenjenim dvodimenzionalnim pozicijama, na model prave linije primenom težinskog potpunog metoda najmanjih kvadrata (Weighted Total Least Squares, WTLS). Prikazan je takođe i tradicionalni postupak rešavanja ovog problema primenom iterativnog algoritma uslovnog izravnanja sa parametrima, odnosno Gauss-Helmertovog modela. Na primeru testiranja pravosti kranske šine, izvršeno je upoređivanje efikasnosti ova dva algoritma u pogledu rezultata ocenjivanja parametara izravnavajuće prave i brzine konvergencije ka finalnom rešenju.
PB  - Savez inženjera i tehničara Srbije, Beograd
T2  - Tehnika
T1  - Testing straightness of line objects using total least squares
T1  - Testiranje pravosti linijskih objekata primenom potpunog metoda najmanjih kvadrata
EP  - 191
IS  - 2
SP  - 187
VL  - 72
DO  - 10.5937/tehnika1702187P
ER  - 

@article{
author = "Popović, Jovan and Aleksić, Ivan R. and Božić, Branko and Milovanović, Branko and Todorović-Drakul, Miljana",
year = "2017",
abstract = "The paper presents the adaptation (fitting) of a set of points, with an estimated two-dimensional positions, to the straight line model of the by the application of the Weighted Total Least Squares, WTLS. The traditional method to solve this problem by using an iterative algorithm of the conditional adjustment with the parameters (Gauss-Helmert's model) is also shown. In the example of testing the straightness of the rail of the crane, a comparison of the efficiency of the two algorithms is performed by means of result of parameter estimation and to the number of required iterations to final solution., U radu je prikazano adaptiranje (fitovanje) skupa tačaka, sa ocenjenim dvodimenzionalnim pozicijama, na model prave linije primenom težinskog potpunog metoda najmanjih kvadrata (Weighted Total Least Squares, WTLS). Prikazan je takođe i tradicionalni postupak rešavanja ovog problema primenom iterativnog algoritma uslovnog izravnanja sa parametrima, odnosno Gauss-Helmertovog modela. Na primeru testiranja pravosti kranske šine, izvršeno je upoređivanje efikasnosti ova dva algoritma u pogledu rezultata ocenjivanja parametara izravnavajuće prave i brzine konvergencije ka finalnom rešenju.",
publisher = "Savez inženjera i tehničara Srbije, Beograd",
journal = "Tehnika",
title = "Testing straightness of line objects using total least squares, Testiranje pravosti linijskih objekata primenom potpunog metoda najmanjih kvadrata",
pages = "191-187",
number = "2",
volume = "72",
doi = "10.5937/tehnika1702187P"
}

Popović, J., Aleksić, I. R., Božić, B., Milovanović, B.,& Todorović-Drakul, M.. (2017). Testing straightness of line objects using total least squares. in Tehnika
Savez inženjera i tehničara Srbije, Beograd., 72(2), 187-191.
https://doi.org/10.5937/tehnika1702187P

Popović J, Aleksić IR, Božić B, Milovanović B, Todorović-Drakul M. Testing straightness of line objects using total least squares. in Tehnika. 2017;72(2):187-191.
doi:10.5937/tehnika1702187P .

Popović, Jovan, Aleksić, Ivan R., Božić, Branko, Milovanović, Branko, Todorović-Drakul, Miljana, "Testing straightness of line objects using total least squares" in Tehnika, 72, no. 2 (2017):187-191,
https://doi.org/10.5937/tehnika1702187P . .

TY  - CONF
AU  - Todorović-Drakul, Miljana
AU  - Odalović, Oleg
AU  - Grekulović, Sanja
PY  - 2017
UR  - https://grafar.grf.bg.ac.rs/handle/123456789/834
AB  - In this paper, a method of calibration of the levelling rod Carl Zeiss Jena No. 55822 was proposed. Within a method procedures we follow the requirement of the International Standard ISO/IEC 17025: 2005 and all necessary observations were performed in the Metrological Laboratory of Institute of Geodesy and Geoinformatics, Faculty of Civil Engineering, University of Belgrade. In the process of the calibration, we used a laser interferometer Hewlett Packard HP 5528 and specially adapted auxiliary equipment for placing the levelling rod in appropriate horizontal position. In addition to the testing of the quality of the graduation of the levelling rod several other properties were examined in order to adequately check the error budget of its application in future Besides of all mentioned, paper also provides an adequate mathematical model of measurement, including the standard estimations of input observation values as well as a measurement uncertainty. The described calibration procedure can be applied to any linear measurement devices.
PB  - International Multidisciplinary Scientific Geoconference
C3  - International Multidisciplinary Scientific GeoConference Surveying Geology and Mining Ecology Manage
T1  - Calibration of the levelling rods using laser interferometer
EP  - 154
IS  - 22
SP  - 147
VL  - 17
DO  - 10.5593/sgem2017/22/S09.019
ER  - 

@conference{
author = "Todorović-Drakul, Miljana and Odalović, Oleg and Grekulović, Sanja",
year = "2017",
abstract = "In this paper, a method of calibration of the levelling rod Carl Zeiss Jena No. 55822 was proposed. Within a method procedures we follow the requirement of the International Standard ISO/IEC 17025: 2005 and all necessary observations were performed in the Metrological Laboratory of Institute of Geodesy and Geoinformatics, Faculty of Civil Engineering, University of Belgrade. In the process of the calibration, we used a laser interferometer Hewlett Packard HP 5528 and specially adapted auxiliary equipment for placing the levelling rod in appropriate horizontal position. In addition to the testing of the quality of the graduation of the levelling rod several other properties were examined in order to adequately check the error budget of its application in future Besides of all mentioned, paper also provides an adequate mathematical model of measurement, including the standard estimations of input observation values as well as a measurement uncertainty. The described calibration procedure can be applied to any linear measurement devices.",
publisher = "International Multidisciplinary Scientific Geoconference",
journal = "International Multidisciplinary Scientific GeoConference Surveying Geology and Mining Ecology Manage",
title = "Calibration of the levelling rods using laser interferometer",
pages = "154-147",
number = "22",
volume = "17",
doi = "10.5593/sgem2017/22/S09.019"
}

Todorović-Drakul, M., Odalović, O.,& Grekulović, S.. (2017). Calibration of the levelling rods using laser interferometer. in International Multidisciplinary Scientific GeoConference Surveying Geology and Mining Ecology Manage
International Multidisciplinary Scientific Geoconference., 17(22), 147-154.
https://doi.org/10.5593/sgem2017/22/S09.019

Todorović-Drakul M, Odalović O, Grekulović S. Calibration of the levelling rods using laser interferometer. in International Multidisciplinary Scientific GeoConference Surveying Geology and Mining Ecology Manage. 2017;17(22):147-154.
doi:10.5593/sgem2017/22/S09.019 .

Todorović-Drakul, Miljana, Odalović, Oleg, Grekulović, Sanja, "Calibration of the levelling rods using laser interferometer" in International Multidisciplinary Scientific GeoConference Surveying Geology and Mining Ecology Manage, 17, no. 22 (2017):147-154,
https://doi.org/10.5593/sgem2017/22/S09.019 . .

TY  - CONF
AU  - Grekulović, Sanja
AU  - Odalović, Oleg
AU  - Todorović-Drakul, Miljana
PY  - 2017
UR  - https://grafar.grf.bg.ac.rs/handle/123456789/833
AB  - In the process of geoid determination one of the most important problems is to determine the effect of topographic masses. Traditionally, solving that particular problem started with the reduction of gravity on the geoid and subsequent calculations the effects of the reduction on the value of the geoid undulations i.e. calculating the indirect effect of reduction. In this paper a model of the indirect effect of Helmert method of condensation over the territory of Serbia was shown. The model was created on the in 5766 points evenly distributed on the territory of Serbia and with the assumption that the density of topographic masses are constant. In the northern parts of the territory of Serbia, which is covered with flat topographic masses, with a maximum altitude of 90 meters, the intensity of the effect reaches a value of -1 cm. Following the direction from north to the south elevation topographic mass gradually are growing so that the value of the indirect the effect gradually increases. All determinations indicate that indirect effect on Serbian territory does not exceed the value of -0.38 m.
PB  - International Multidisciplinary Scientific Geoconference
C3  - International Multidisciplinary Scientific GeoConference Surveying Geology and Mining Ecology Manage
T1  - Indirect effect of the helmert condensation reduction over the territory of Serbia
EP  - 360
IS  - 22
SP  - 355
VL  - 17
DO  - 10.5593/sgem2017/22/S09.044
ER  - 

@conference{
author = "Grekulović, Sanja and Odalović, Oleg and Todorović-Drakul, Miljana",
year = "2017",
abstract = "In the process of geoid determination one of the most important problems is to determine the effect of topographic masses. Traditionally, solving that particular problem started with the reduction of gravity on the geoid and subsequent calculations the effects of the reduction on the value of the geoid undulations i.e. calculating the indirect effect of reduction. In this paper a model of the indirect effect of Helmert method of condensation over the territory of Serbia was shown. The model was created on the in 5766 points evenly distributed on the territory of Serbia and with the assumption that the density of topographic masses are constant. In the northern parts of the territory of Serbia, which is covered with flat topographic masses, with a maximum altitude of 90 meters, the intensity of the effect reaches a value of -1 cm. Following the direction from north to the south elevation topographic mass gradually are growing so that the value of the indirect the effect gradually increases. All determinations indicate that indirect effect on Serbian territory does not exceed the value of -0.38 m.",
publisher = "International Multidisciplinary Scientific Geoconference",
journal = "International Multidisciplinary Scientific GeoConference Surveying Geology and Mining Ecology Manage",
title = "Indirect effect of the helmert condensation reduction over the territory of Serbia",
pages = "360-355",
number = "22",
volume = "17",
doi = "10.5593/sgem2017/22/S09.044"
}

Grekulović, S., Odalović, O.,& Todorović-Drakul, M.. (2017). Indirect effect of the helmert condensation reduction over the territory of Serbia. in International Multidisciplinary Scientific GeoConference Surveying Geology and Mining Ecology Manage
International Multidisciplinary Scientific Geoconference., 17(22), 355-360.
https://doi.org/10.5593/sgem2017/22/S09.044

Grekulović S, Odalović O, Todorović-Drakul M. Indirect effect of the helmert condensation reduction over the territory of Serbia. in International Multidisciplinary Scientific GeoConference Surveying Geology and Mining Ecology Manage. 2017;17(22):355-360.
doi:10.5593/sgem2017/22/S09.044 .

Grekulović, Sanja, Odalović, Oleg, Todorović-Drakul, Miljana, "Indirect effect of the helmert condensation reduction over the territory of Serbia" in International Multidisciplinary Scientific GeoConference Surveying Geology and Mining Ecology Manage, 17, no. 22 (2017):355-360,
https://doi.org/10.5593/sgem2017/22/S09.044 . .

TY  - CONF
AU  - Todorović-Drakul, Miljana
AU  - Samardžić-Petrović, Mileva
AU  - Grekulović, Sanja
AU  - Odalović, Oleg
AU  - Blagojević, Dragan
PY  - 2016
UR  - https://grafar.grf.bg.ac.rs/handle/123456789/1430
PB  - Faculty of Civil Engineering, Belgrade
C3  - Proceedings of GeoMLA, Geostatistics and Machine Learning, Application in Climate and Environmental Sciences, Belgrade, Serbia 21-24 June 2016
T1  - Total electron content prediction using machine learning techniques
EP  - 44
SP  - 40
UR  - https://hdl.handle.net/21.15107/rcub_grafar_1430
ER  - 

@conference{
author = "Todorović-Drakul, Miljana and Samardžić-Petrović, Mileva and Grekulović, Sanja and Odalović, Oleg and Blagojević, Dragan",
year = "2016",
publisher = "Faculty of Civil Engineering, Belgrade",
journal = "Proceedings of GeoMLA, Geostatistics and Machine Learning, Application in Climate and Environmental Sciences, Belgrade, Serbia 21-24 June 2016",
title = "Total electron content prediction using machine learning techniques",
pages = "44-40",
url = "https://hdl.handle.net/21.15107/rcub_grafar_1430"
}

Todorović-Drakul, M., Samardžić-Petrović, M., Grekulović, S., Odalović, O.,& Blagojević, D.. (2016). Total electron content prediction using machine learning techniques. in Proceedings of GeoMLA, Geostatistics and Machine Learning, Application in Climate and Environmental Sciences, Belgrade, Serbia 21-24 June 2016
Faculty of Civil Engineering, Belgrade., 40-44.
https://hdl.handle.net/21.15107/rcub_grafar_1430

Todorović-Drakul M, Samardžić-Petrović M, Grekulović S, Odalović O, Blagojević D. Total electron content prediction using machine learning techniques. in Proceedings of GeoMLA, Geostatistics and Machine Learning, Application in Climate and Environmental Sciences, Belgrade, Serbia 21-24 June 2016. 2016;:40-44.
https://hdl.handle.net/21.15107/rcub_grafar_1430 .

Todorović-Drakul, Miljana, Samardžić-Petrović, Mileva, Grekulović, Sanja, Odalović, Oleg, Blagojević, Dragan, "Total electron content prediction using machine learning techniques" in Proceedings of GeoMLA, Geostatistics and Machine Learning, Application in Climate and Environmental Sciences, Belgrade, Serbia 21-24 June 2016 (2016):40-44,
https://hdl.handle.net/21.15107/rcub_grafar_1430 .

TY  - JOUR
AU  - Blagojević, Dragan
AU  - Todorović-Drakul, Miljana
AU  - Odalović, Oleg
AU  - Grekulović, Sanja
AU  - Popović, Jovan
AU  - Joksimović, Danilo
PY  - 2016
UR  - https://grafar.grf.bg.ac.rs/handle/123456789/804
AB  - To understand general ionosphere properties over Serbia, an analysis of temporal and spatial ionosphere Total Electron Content (TEC) over the region was performed. The present research focuses on daily, seasonal and spatial ionosphere variations, based on TEC series calculated from the GNSS ie. GPS measurements. This analysis provides for characterization of ionosphere nature and fine structure over Serbia, both locally and regionally. For the days with high solar activity changes of TEC values ranges from minimum 4 Total Electron Content Units (TECU), in night hours, up to 55 TECU around the noon. It is shown that that changes are equivalent to the to the delay of GPS signals approximately 8.8 m in in vertical direction during the (maximum) daily conditions and the delay of 0.6 m during the (minimum) night conditions. Also, it is shows that a seasonal TEC differences follows directly Son activity during the seasons, and maximal differences of TEC values between the seasons reaching values of 45 TECU, again in the years of high Son's activities. For spatial changes all gained results indicate that there exist changes in all directions which cannot be recognized as constant bias or a trend.
PB  - Zvava Geodetov Slovenije
T2  - Geodetski vestnik
T1  - Variations of total electron content over Serbia during the increased solar activity period in 2013 and 2014
EP  - 744
IS  - 4
SP  - 734
VL  - 60
DO  - 10.15292/geodetski-vestnik.2016.04.734-744
ER  - 

@article{
author = "Blagojević, Dragan and Todorović-Drakul, Miljana and Odalović, Oleg and Grekulović, Sanja and Popović, Jovan and Joksimović, Danilo",
year = "2016",
abstract = "To understand general ionosphere properties over Serbia, an analysis of temporal and spatial ionosphere Total Electron Content (TEC) over the region was performed. The present research focuses on daily, seasonal and spatial ionosphere variations, based on TEC series calculated from the GNSS ie. GPS measurements. This analysis provides for characterization of ionosphere nature and fine structure over Serbia, both locally and regionally. For the days with high solar activity changes of TEC values ranges from minimum 4 Total Electron Content Units (TECU), in night hours, up to 55 TECU around the noon. It is shown that that changes are equivalent to the to the delay of GPS signals approximately 8.8 m in in vertical direction during the (maximum) daily conditions and the delay of 0.6 m during the (minimum) night conditions. Also, it is shows that a seasonal TEC differences follows directly Son activity during the seasons, and maximal differences of TEC values between the seasons reaching values of 45 TECU, again in the years of high Son's activities. For spatial changes all gained results indicate that there exist changes in all directions which cannot be recognized as constant bias or a trend.",
publisher = "Zvava Geodetov Slovenije",
journal = "Geodetski vestnik",
title = "Variations of total electron content over Serbia during the increased solar activity period in 2013 and 2014",
pages = "744-734",
number = "4",
volume = "60",
doi = "10.15292/geodetski-vestnik.2016.04.734-744"
}

Blagojević, D., Todorović-Drakul, M., Odalović, O., Grekulović, S., Popović, J.,& Joksimović, D.. (2016). Variations of total electron content over Serbia during the increased solar activity period in 2013 and 2014. in Geodetski vestnik
Zvava Geodetov Slovenije., 60(4), 734-744.
https://doi.org/10.15292/geodetski-vestnik.2016.04.734-744

Blagojević D, Todorović-Drakul M, Odalović O, Grekulović S, Popović J, Joksimović D. Variations of total electron content over Serbia during the increased solar activity period in 2013 and 2014. in Geodetski vestnik. 2016;60(4):734-744.
doi:10.15292/geodetski-vestnik.2016.04.734-744 .

Blagojević, Dragan, Todorović-Drakul, Miljana, Odalović, Oleg, Grekulović, Sanja, Popović, Jovan, Joksimović, Danilo, "Variations of total electron content over Serbia during the increased solar activity period in 2013 and 2014" in Geodetski vestnik, 60, no. 4 (2016):734-744,
https://doi.org/10.15292/geodetski-vestnik.2016.04.734-744 . .

TY  - THES
AU  - Todorović-Drakul, Miljana
PY  - 2016
UR  - http://eteze.bg.ac.rs/application/showtheses?thesesId=4776
UR  - https://fedorabg.bg.ac.rs/fedora/get/o:15060/bdef:Content/download
UR  - http://vbs.rs/scripts/cobiss?command=DISPLAY&base=70036&RID=513748114
UR  - http://nardus.mpn.gov.rs/123456789/7880
UR  - https://grafar.grf.bg.ac.rs/handle/123456789/1703
AB  - Докторска дисертација посвећена је развоју одговарајућег модела за потребепредикције јоносферских корекција задовољавајуће тачности за мрежне RTK (енг.Real Time Kinematic) апликације.Као први корак ка остварењу овог циља вршено је испитивање краткорочнихвременских карактеристика јоносфере на регионалном просторном нивоу, како бисе квантификовало њено понашање током различитих сезонских и дневнихпериода. Коришћени су подаци са мреже перманентних станица на територијиРепублике Србије. Анализа је вршена за четири различита сезонска периодатоком претходног соларног максимума током 2013. и 2014. године.Након тога вршено је анализирање промена садржаја електрона у D регионуизазваним соларним Х-флеровима на основу чега су истраживане временскепромене ТЕСD (енг. Total Electron Content in D region) и њихов удео у укупномТЕС (енг. Total Electron Content) односно укупном кашњењу GPS (GlobalPositioning System) сигнала.На крају приступљено је дефинисању одговарајућег модела за потребе предикцијејоносферских корекција за мрежне RTK примене на територији Србије. Тестиранесу две предиктивне шеме базиране на методу линеарне регресије и применинеуронских мрежа.Показало се да примена неуронских мрежа даје боље резултате и да је у стању дапредиктује јоносферско кашњење на нивоу тачности од ± 5cm у просеку од око 9минута у односу на реалну стопу јоносферских промена. Ови резултати сугеришуда техника моделовања применом неуронских мрежа, може да се примени кодмрежа RTK система за предиктовање грешке јоносферског кашњења који ћеомогућити позиционирање на центиметарском нивоу тачности...
AB  - Doctoral dissertation is dedicated to the development an of appropriate model for thepurposes of prediction of ionospheric corrections with satisfactory accuracy for networkRTK (Real Time Kinematic) applications.As a first step towards achieving this goal, short-term temporal ionosphericcharacteristics on regional spatial level were investigated in order to quantify itsbehaviour during different seasonal and daily periods. Data from permanent networkstations on the territory of the Republic of Serbia were used. The analysis wasconducted for four different season periods during the previous solar maximum duringthe years 2013 and 2014.After that the analysis of the change in the content of electrons in the D region causedby solar X-flares was performed, based upon which the temporal changes ТЕСD (TotalElectron Content in D region) and their share in total TEC (Total Electron Content), i.e.the total delay of GPS (Global Positioning System) signals were investigated.Finally, an appropriate model for the purpose of the prediction of ionosphericcorrections for network RTK applications on the territory of the Republic of Serbia isproduced. Two predictive schemes based on the linear regression method and on the useof neuron networks were tested.It has been shown that the use of the neuron networks gives better results and is able topredict ionospheric delay on ±5 cm accuracy level in 9 minutes average in regards to thereal rate of ionospheric changes. These results suggest that the modelling techniqueusing neuron networks can be applied for predicting the ionospheric delay error innetwork RTK systems that will enable centimeter level positioning...
PB  - Универзитет у Београду, Архитектонски факултет
T2  - Универзитет у Београду
T1  - Моделовање јоносфере за потребе одређивања утицаја на ГПС сигнале у мрежном РТК окружењу
UR  - https://hdl.handle.net/21.15107/rcub_nardus_7880
ER  - 

@phdthesis{
author = "Todorović-Drakul, Miljana",
year = "2016",
abstract = "Докторска дисертација посвећена је развоју одговарајућег модела за потребепредикције јоносферских корекција задовољавајуће тачности за мрежне RTK (енг.Real Time Kinematic) апликације.Као први корак ка остварењу овог циља вршено је испитивање краткорочнихвременских карактеристика јоносфере на регионалном просторном нивоу, како бисе квантификовало њено понашање током различитих сезонских и дневнихпериода. Коришћени су подаци са мреже перманентних станица на територијиРепублике Србије. Анализа је вршена за четири различита сезонска периодатоком претходног соларног максимума током 2013. и 2014. године.Након тога вршено је анализирање промена садржаја електрона у D регионуизазваним соларним Х-флеровима на основу чега су истраживане временскепромене ТЕСD (енг. Total Electron Content in D region) и њихов удео у укупномТЕС (енг. Total Electron Content) односно укупном кашњењу GPS (GlobalPositioning System) сигнала.На крају приступљено је дефинисању одговарајућег модела за потребе предикцијејоносферских корекција за мрежне RTK примене на територији Србије. Тестиранесу две предиктивне шеме базиране на методу линеарне регресије и применинеуронских мрежа.Показало се да примена неуронских мрежа даје боље резултате и да је у стању дапредиктује јоносферско кашњење на нивоу тачности од ± 5cm у просеку од око 9минута у односу на реалну стопу јоносферских промена. Ови резултати сугеришуда техника моделовања применом неуронских мрежа, може да се примени кодмрежа RTK система за предиктовање грешке јоносферског кашњења који ћеомогућити позиционирање на центиметарском нивоу тачности..., Doctoral dissertation is dedicated to the development an of appropriate model for thepurposes of prediction of ionospheric corrections with satisfactory accuracy for networkRTK (Real Time Kinematic) applications.As a first step towards achieving this goal, short-term temporal ionosphericcharacteristics on regional spatial level were investigated in order to quantify itsbehaviour during different seasonal and daily periods. Data from permanent networkstations on the territory of the Republic of Serbia were used. The analysis wasconducted for four different season periods during the previous solar maximum duringthe years 2013 and 2014.After that the analysis of the change in the content of electrons in the D region causedby solar X-flares was performed, based upon which the temporal changes ТЕСD (TotalElectron Content in D region) and their share in total TEC (Total Electron Content), i.e.the total delay of GPS (Global Positioning System) signals were investigated.Finally, an appropriate model for the purpose of the prediction of ionosphericcorrections for network RTK applications on the territory of the Republic of Serbia isproduced. Two predictive schemes based on the linear regression method and on the useof neuron networks were tested.It has been shown that the use of the neuron networks gives better results and is able topredict ionospheric delay on ±5 cm accuracy level in 9 minutes average in regards to thereal rate of ionospheric changes. These results suggest that the modelling techniqueusing neuron networks can be applied for predicting the ionospheric delay error innetwork RTK systems that will enable centimeter level positioning...",
publisher = "Универзитет у Београду, Архитектонски факултет",
journal = "Универзитет у Београду",
title = "Моделовање јоносфере за потребе одређивања утицаја на ГПС сигнале у мрежном РТК окружењу",
url = "https://hdl.handle.net/21.15107/rcub_nardus_7880"
}

Todorović-Drakul, M.. (2016). Моделовање јоносфере за потребе одређивања утицаја на ГПС сигнале у мрежном РТК окружењу. in Универзитет у Београду
Универзитет у Београду, Архитектонски факултет..
https://hdl.handle.net/21.15107/rcub_nardus_7880

Todorović-Drakul M. Моделовање јоносфере за потребе одређивања утицаја на ГПС сигнале у мрежном РТК окружењу. in Универзитет у Београду. 2016;.
https://hdl.handle.net/21.15107/rcub_nardus_7880 .

Todorović-Drakul, Miljana, "Моделовање јоносфере за потребе одређивања утицаја на ГПС сигнале у мрежном РТК окружењу" in Универзитет у Београду (2016),
https://hdl.handle.net/21.15107/rcub_nardus_7880 .

TY  - JOUR
AU  - Todorović-Drakul, Miljana
AU  - Cadez, V.M.
AU  - Bajcetić, J.
AU  - Popović, L. C.
AU  - Blagojević, Dragan
AU  - Nina, A.
PY  - 2016
UR  - https://grafar.grf.bg.ac.rs/handle/123456789/736
AB  - One of the most important parameters in ionospheric plasma research, also having a wide practical application in wireless satellite telecommunications, is the total electron content (TEC) representing the columnal electron number density. The F-region with high electron density provides the biggest contribution to TEC while the relatively weakly ionized plasma of the D-region (60 km 90 km above Earth's surface) is often considered as a negligible cause of satellite signal disturbances. However, sudden intensive ionization processes, like those induced by solar X-ray flares, can cause relative increases of electron density that are significantly larger in the D-region than in regions at higher altitudes. Therefore, one cannot exclude a priori the D-region from investigations of ionospheric influences on propagation of electromagnetic signals emitted by satellites. We discuss here this problem which has not been sufficiently treated in literature so far. The obtained results are based on data collected from the D-region monitoring by very low frequency radio waves and on vertical TEC calculations from the Global Navigation Satellite System (GNSS) signal analyses, and they show noticeable variations in the D-region's electron content (TECD) during activity of a solar X-ray flare (it rises by a factor of 136 in the considered case) when TECD contribution to TEC can reach several percent and which cannot be neglected in practical applications like global positioning procedures by satellites.
PB  - Astronomska opservatorija, Beograd i Univerzitet u Beogradu - Matematički fakultet - Odeljenje za astronomiju, Beograd
T2  - Serbian Astronomical Journal
T1  - Behaviour of electron content in the ionospheric d-region during solar x-ray flares
EP  - 18
SP  - 11
VL  - 193
DO  - 10.2298/SAJ160404006T
ER  - 

@article{
author = "Todorović-Drakul, Miljana and Cadez, V.M. and Bajcetić, J. and Popović, L. C. and Blagojević, Dragan and Nina, A.",
year = "2016",
abstract = "One of the most important parameters in ionospheric plasma research, also having a wide practical application in wireless satellite telecommunications, is the total electron content (TEC) representing the columnal electron number density. The F-region with high electron density provides the biggest contribution to TEC while the relatively weakly ionized plasma of the D-region (60 km 90 km above Earth's surface) is often considered as a negligible cause of satellite signal disturbances. However, sudden intensive ionization processes, like those induced by solar X-ray flares, can cause relative increases of electron density that are significantly larger in the D-region than in regions at higher altitudes. Therefore, one cannot exclude a priori the D-region from investigations of ionospheric influences on propagation of electromagnetic signals emitted by satellites. We discuss here this problem which has not been sufficiently treated in literature so far. The obtained results are based on data collected from the D-region monitoring by very low frequency radio waves and on vertical TEC calculations from the Global Navigation Satellite System (GNSS) signal analyses, and they show noticeable variations in the D-region's electron content (TECD) during activity of a solar X-ray flare (it rises by a factor of 136 in the considered case) when TECD contribution to TEC can reach several percent and which cannot be neglected in practical applications like global positioning procedures by satellites.",
publisher = "Astronomska opservatorija, Beograd i Univerzitet u Beogradu - Matematički fakultet - Odeljenje za astronomiju, Beograd",
journal = "Serbian Astronomical Journal",
title = "Behaviour of electron content in the ionospheric d-region during solar x-ray flares",
pages = "18-11",
volume = "193",
doi = "10.2298/SAJ160404006T"
}

Todorović-Drakul, M., Cadez, V.M., Bajcetić, J., Popović, L. C., Blagojević, D.,& Nina, A.. (2016). Behaviour of electron content in the ionospheric d-region during solar x-ray flares. in Serbian Astronomical Journal
Astronomska opservatorija, Beograd i Univerzitet u Beogradu - Matematički fakultet - Odeljenje za astronomiju, Beograd., 193, 11-18.
https://doi.org/10.2298/SAJ160404006T

Todorović-Drakul M, Cadez V, Bajcetić J, Popović LC, Blagojević D, Nina A. Behaviour of electron content in the ionospheric d-region during solar x-ray flares. in Serbian Astronomical Journal. 2016;193:11-18.
doi:10.2298/SAJ160404006T .

Todorović-Drakul, Miljana, Cadez, V.M., Bajcetić, J., Popović, L. C., Blagojević, Dragan, Nina, A., "Behaviour of electron content in the ionospheric d-region during solar x-ray flares" in Serbian Astronomical Journal, 193 (2016):11-18,
https://doi.org/10.2298/SAJ160404006T . .

TY  - CONF
AU  - Odalović, Oleg
AU  - Grekulović, Sanja
AU  - Joksimović, Danilo
AU  - Todorović-Drakul, Miljana
AU  - Popović, Jovan
PY  - 2016
UR  - https://grafar.grf.bg.ac.rs/handle/123456789/780
AB  - This paper presents determination of height anomalies by the means of Global Geopotential Model 2008 (EGM08). Height anomalies were determined at 1073 points over the territory of Serbia, with known discrete values of height anomalies, which were also determined by satellite leveling. For each of the points, cumulative results of determination had been archived during the calculation for each degree, from 0 to 2190, thus 2191 results of determination were at the disposal for a point. The results obtained were compared with the discrete height anomaly values, and it was concluded that the highest quality of approximation for the discrete undulation values is being achieved using only coefficients up to 1181st degree, thus the present paper shall designate it: the optimal degree.
C3  - Informatics, Geoinformatics and Remote Sensing Conference Proceedings, Sgem 2016, Vol II
T1  - Selection of the global geopotential model 2008 optimal degree for height anomalies determination
EP  - 546
SP  - 539
UR  - https://hdl.handle.net/21.15107/rcub_grafar_780
ER  - 

@conference{
author = "Odalović, Oleg and Grekulović, Sanja and Joksimović, Danilo and Todorović-Drakul, Miljana and Popović, Jovan",
year = "2016",
abstract = "This paper presents determination of height anomalies by the means of Global Geopotential Model 2008 (EGM08). Height anomalies were determined at 1073 points over the territory of Serbia, with known discrete values of height anomalies, which were also determined by satellite leveling. For each of the points, cumulative results of determination had been archived during the calculation for each degree, from 0 to 2190, thus 2191 results of determination were at the disposal for a point. The results obtained were compared with the discrete height anomaly values, and it was concluded that the highest quality of approximation for the discrete undulation values is being achieved using only coefficients up to 1181st degree, thus the present paper shall designate it: the optimal degree.",
journal = "Informatics, Geoinformatics and Remote Sensing Conference Proceedings, Sgem 2016, Vol II",
title = "Selection of the global geopotential model 2008 optimal degree for height anomalies determination",
pages = "546-539",
url = "https://hdl.handle.net/21.15107/rcub_grafar_780"
}

Odalović, O., Grekulović, S., Joksimović, D., Todorović-Drakul, M.,& Popović, J.. (2016). Selection of the global geopotential model 2008 optimal degree for height anomalies determination. in Informatics, Geoinformatics and Remote Sensing Conference Proceedings, Sgem 2016, Vol II, 539-546.
https://hdl.handle.net/21.15107/rcub_grafar_780

Odalović O, Grekulović S, Joksimović D, Todorović-Drakul M, Popović J. Selection of the global geopotential model 2008 optimal degree for height anomalies determination. in Informatics, Geoinformatics and Remote Sensing Conference Proceedings, Sgem 2016, Vol II. 2016;:539-546.
https://hdl.handle.net/21.15107/rcub_grafar_780 .

Odalović, Oleg, Grekulović, Sanja, Joksimović, Danilo, Todorović-Drakul, Miljana, Popović, Jovan, "Selection of the global geopotential model 2008 optimal degree for height anomalies determination" in Informatics, Geoinformatics and Remote Sensing Conference Proceedings, Sgem 2016, Vol II (2016):539-546,
https://hdl.handle.net/21.15107/rcub_grafar_780 .

TY  - CONF
AU  - Odalović, Oleg
AU  - Grekulović, Sanja
AU  - Joksimović, Danilo
AU  - Todorović-Drakul, Miljana
AU  - Popović, Jovan
PY  - 2016
UR  - https://grafar.grf.bg.ac.rs/handle/123456789/737
AB  - This paper presents the evaluation and comparison test of a series of global geopotential models (GGM) using available terrestrial data over the territory of Montenegro. Using the model of Gravity Observation Combination 02S and 03S (G00002S and GOCO03S) with three different approaches (space-wise approach, time-wise approach, and direct approach) as well as the model of the Earth Gravitational Model 2008 (EGM08) and Earth Gravitational Model 1996 (EGM96) the anomalies of free air at 1293 points of gravimetric survey of Montenegro were determined; as well as the height anomalies at 46 points for which the discreet values of height anomalies are known. The discreet values of height anomalies were calculated as differences between orthometric heights, determined by high precision levelling and the ellipsoidal heights determined by the global positioning system (GPS/dh); and at the points of gravimetric survey of Montenegro, the free air anomalies related to the Geodetic Reference System 1980 (GRS80) and to the International Gravity Standardization Net 1971 (IGSN71) were determined. The data used in this paper are the data of gravimetric survey of former Socialistic Federative Republic of Yugoslavia, and the data of the height anomalies discreet values are data collected in March 2015 for further scientific research, particularly for geoid/quasigeoid determination for Montenegro.
C3  - Informatics, Geoinformatics and Remote Sensing Conference Proceedings, Sgem 2016, Vol II
T1  - Determination of discrete values of anomaly heights at territory of Montenegro
EP  - 184
SP  - 177
UR  - https://hdl.handle.net/21.15107/rcub_grafar_737
ER  - 

@conference{
author = "Odalović, Oleg and Grekulović, Sanja and Joksimović, Danilo and Todorović-Drakul, Miljana and Popović, Jovan",
year = "2016",
abstract = "This paper presents the evaluation and comparison test of a series of global geopotential models (GGM) using available terrestrial data over the territory of Montenegro. Using the model of Gravity Observation Combination 02S and 03S (G00002S and GOCO03S) with three different approaches (space-wise approach, time-wise approach, and direct approach) as well as the model of the Earth Gravitational Model 2008 (EGM08) and Earth Gravitational Model 1996 (EGM96) the anomalies of free air at 1293 points of gravimetric survey of Montenegro were determined; as well as the height anomalies at 46 points for which the discreet values of height anomalies are known. The discreet values of height anomalies were calculated as differences between orthometric heights, determined by high precision levelling and the ellipsoidal heights determined by the global positioning system (GPS/dh); and at the points of gravimetric survey of Montenegro, the free air anomalies related to the Geodetic Reference System 1980 (GRS80) and to the International Gravity Standardization Net 1971 (IGSN71) were determined. The data used in this paper are the data of gravimetric survey of former Socialistic Federative Republic of Yugoslavia, and the data of the height anomalies discreet values are data collected in March 2015 for further scientific research, particularly for geoid/quasigeoid determination for Montenegro.",
journal = "Informatics, Geoinformatics and Remote Sensing Conference Proceedings, Sgem 2016, Vol II",
title = "Determination of discrete values of anomaly heights at territory of Montenegro",
pages = "184-177",
url = "https://hdl.handle.net/21.15107/rcub_grafar_737"
}

Odalović, O., Grekulović, S., Joksimović, D., Todorović-Drakul, M.,& Popović, J.. (2016). Determination of discrete values of anomaly heights at territory of Montenegro. in Informatics, Geoinformatics and Remote Sensing Conference Proceedings, Sgem 2016, Vol II, 177-184.
https://hdl.handle.net/21.15107/rcub_grafar_737

Odalović O, Grekulović S, Joksimović D, Todorović-Drakul M, Popović J. Determination of discrete values of anomaly heights at territory of Montenegro. in Informatics, Geoinformatics and Remote Sensing Conference Proceedings, Sgem 2016, Vol II. 2016;:177-184.
https://hdl.handle.net/21.15107/rcub_grafar_737 .

Odalović, Oleg, Grekulović, Sanja, Joksimović, Danilo, Todorović-Drakul, Miljana, Popović, Jovan, "Determination of discrete values of anomaly heights at territory of Montenegro" in Informatics, Geoinformatics and Remote Sensing Conference Proceedings, Sgem 2016, Vol II (2016):177-184,
https://hdl.handle.net/21.15107/rcub_grafar_737 .

TY  - JOUR
AU  - Odalović, Oleg
AU  - Joksimović, Danilo
AU  - Grekulović, Sanja
AU  - Todorović-Drakul, Miljana
AU  - Popović, Jovan
PY  - 2015
UR  - https://grafar.grf.bg.ac.rs/handle/123456789/2235
AB  - This paper presents geometrically and physically defined height systems, along with their evaluation by the means of Global Navigation Satellite Systems (GNSS) and Global Geopotential Models (GGM). The paper defines ellipsoid heights as an instance of geometrically defined heights; with physically defined heights being represented by definitions of orthometric and normal heights. Methods of normal heights calculation by the means of ellipsoid heights are presented in detail, as determined using the GNSS and height anomalies calculated from the
GGM application. Apart from the above, numerical part of the paper evaluates normal height values and compares them to their conditionally accurate values at 1073 points with relatively uniform distribution over the entire territory of Serbia. Conditionally accurate values had been determined by the means of classical geodetic terrestrial methods. Under the procedure of evaluating normal height values, GGM – GGM05C was used, as created in 2016 by the Center for Space Research, University of Texas at Austin. In order to evaluate the quality of applying the
model above, data on normal heights evaluation were also presented, using the GGM EGM96, created in 1996 by the National Imagery and Mapping Agency (NIMA), Goddard Space Flight Center (GSFC – NASA) and Ohio State University, presently being the most commonly used model. The comparison above indicates that application of the GGM05C model provides 50 % greater quality of normal heights evaluations against the ones obtained using the EGM96 model.
AB  - У оквиру рада приказани су геометријски и физички дефинисани системи висина, као и
њихова оцена применом глобалних навигационих сателитских система (GNSS) и глобалних
геопотенцијалних модела (GGM). У раду је дата дефиниција елипсоидних висина као представника геометријски дефинисаних висина, а у погледу физички дефинисаних висина приказане су дефиниције ортометријских и нормалних висина. Детаљно су представљени начини рачунања нормалних висина применом елипсоидних висина, које су одређене применом GNSS и аномалија висина које следе из примене GGM. Поред наведеног у нумеричком делу рада оцењене су вредности нормалних висина и упоређене са њиховим условно тачним вредностима и то у 1073 тачке које су релативно правилно распоређене по читавој територији Србије. Условно тачне вредности одређене су применом класичних
геодетских терестричких метода. У поступку оцене вредности нормалних висина коришћен је GGM GGM05C који је креиран 2016. године од стране Центра за космичка истраживања у Тексасу (Center for Space Research, Univesity of Texas at Austin). У циљу оцене квалитета примене наведеног модела приказани су и подаци оцене нормалних висина при примени GGM EGM96 који је креиран 1996. године од стране Националне агенције за дигиталну обраду слика и картирање (National Imagery and Mapping Agency - NIMA), Центра за космичке летове Националне космичке агенције (Goddard Space Flight Center – GSFC - NASA) и америчког Универзитета Охајо (Ohio State University), који до данас представља најчешће коришћени модел. Из наведеног упоређења следи да се применом модела
GGM05C добијају 50% квалитетније оцене нормалних висина од оних које следе из примене модела EGM96.
T2  - Glasnik Srpskog geografskog drustva
T1  - Evaluation of normal heights by the means of global navigation satellite systems and global geopotential model
SP  - 103-124
DO  - https://doi.org/10.2298/GSGD1504103O
ER  - 

@article{
author = "Odalović, Oleg and Joksimović, Danilo and Grekulović, Sanja and Todorović-Drakul, Miljana and Popović, Jovan",
year = "2015",
abstract = "This paper presents geometrically and physically defined height systems, along with their evaluation by the means of Global Navigation Satellite Systems (GNSS) and Global Geopotential Models (GGM). The paper defines ellipsoid heights as an instance of geometrically defined heights; with physically defined heights being represented by definitions of orthometric and normal heights. Methods of normal heights calculation by the means of ellipsoid heights are presented in detail, as determined using the GNSS and height anomalies calculated from the
GGM application. Apart from the above, numerical part of the paper evaluates normal height values and compares them to their conditionally accurate values at 1073 points with relatively uniform distribution over the entire territory of Serbia. Conditionally accurate values had been determined by the means of classical geodetic terrestrial methods. Under the procedure of evaluating normal height values, GGM – GGM05C was used, as created in 2016 by the Center for Space Research, University of Texas at Austin. In order to evaluate the quality of applying the
model above, data on normal heights evaluation were also presented, using the GGM EGM96, created in 1996 by the National Imagery and Mapping Agency (NIMA), Goddard Space Flight Center (GSFC – NASA) and Ohio State University, presently being the most commonly used model. The comparison above indicates that application of the GGM05C model provides 50 % greater quality of normal heights evaluations against the ones obtained using the EGM96 model., У оквиру рада приказани су геометријски и физички дефинисани системи висина, као и
њихова оцена применом глобалних навигационих сателитских система (GNSS) и глобалних
геопотенцијалних модела (GGM). У раду је дата дефиниција елипсоидних висина као представника геометријски дефинисаних висина, а у погледу физички дефинисаних висина приказане су дефиниције ортометријских и нормалних висина. Детаљно су представљени начини рачунања нормалних висина применом елипсоидних висина, које су одређене применом GNSS и аномалија висина које следе из примене GGM. Поред наведеног у нумеричком делу рада оцењене су вредности нормалних висина и упоређене са њиховим условно тачним вредностима и то у 1073 тачке које су релативно правилно распоређене по читавој територији Србије. Условно тачне вредности одређене су применом класичних
геодетских терестричких метода. У поступку оцене вредности нормалних висина коришћен је GGM GGM05C који је креиран 2016. године од стране Центра за космичка истраживања у Тексасу (Center for Space Research, Univesity of Texas at Austin). У циљу оцене квалитета примене наведеног модела приказани су и подаци оцене нормалних висина при примени GGM EGM96 који је креиран 1996. године од стране Националне агенције за дигиталну обраду слика и картирање (National Imagery and Mapping Agency - NIMA), Центра за космичке летове Националне космичке агенције (Goddard Space Flight Center – GSFC - NASA) и америчког Универзитета Охајо (Ohio State University), који до данас представља најчешће коришћени модел. Из наведеног упоређења следи да се применом модела
GGM05C добијају 50% квалитетније оцене нормалних висина од оних које следе из примене модела EGM96.",
journal = "Glasnik Srpskog geografskog drustva",
title = "Evaluation of normal heights by the means of global navigation satellite systems and global geopotential model",
pages = "103-124",
doi = "https://doi.org/10.2298/GSGD1504103O"
}

Odalović, O., Joksimović, D., Grekulović, S., Todorović-Drakul, M.,& Popović, J.. (2015). Evaluation of normal heights by the means of global navigation satellite systems and global geopotential model. in Glasnik Srpskog geografskog drustva, 103-124.
https://doi.org/https://doi.org/10.2298/GSGD1504103O

Odalović O, Joksimović D, Grekulović S, Todorović-Drakul M, Popović J. Evaluation of normal heights by the means of global navigation satellite systems and global geopotential model. in Glasnik Srpskog geografskog drustva. 2015;:103-124.
doi:https://doi.org/10.2298/GSGD1504103O .

Odalović, Oleg, Joksimović, Danilo, Grekulović, Sanja, Todorović-Drakul, Miljana, Popović, Jovan, "Evaluation of normal heights by the means of global navigation satellite systems and global geopotential model" in Glasnik Srpskog geografskog drustva (2015):103-124,
https://doi.org/https://doi.org/10.2298/GSGD1504103O . .

TY  - CONF
AU  - Odalović, Oleg
AU  - Grekulović, Sanja
AU  - Vasiljević, Ivana
AU  - Todorović-Drakul, Miljana
AU  - Popović, Jovan
PY  - 2015
UR  - https://grafar.grf.bg.ac.rs/handle/123456789/660
AB  - In the last few years several solutions for gravimetric geoid/quasigeoid for the territory of Serbia were determined. All the solutions meant usage of remove-restore method applying a) detailed gravimetric survey b) appropriate global geopotential model and c) digital terrain model. After determining gravimetric solutions it is necessary to perform their transformation into the system of orthometric i.e. normal heights of high precision leveling network to enable their practical usage in topographic survey. In this paperwork the way of transforming a preliminary gravimetric geoid into the system of orthometric leveling heights of Serbia network is presented.
C3  - Informatics, Geoinformatics and Remote Sensing, Vol II (Sgem 2015)
T1  - Transformation of gravimetric geoid/quasigeoid in the system of orthometric/normal heights of Serbia leveling network
EP  - 601
SP  - 593
UR  - https://hdl.handle.net/21.15107/rcub_grafar_660
ER  - 

@conference{
author = "Odalović, Oleg and Grekulović, Sanja and Vasiljević, Ivana and Todorović-Drakul, Miljana and Popović, Jovan",
year = "2015",
abstract = "In the last few years several solutions for gravimetric geoid/quasigeoid for the territory of Serbia were determined. All the solutions meant usage of remove-restore method applying a) detailed gravimetric survey b) appropriate global geopotential model and c) digital terrain model. After determining gravimetric solutions it is necessary to perform their transformation into the system of orthometric i.e. normal heights of high precision leveling network to enable their practical usage in topographic survey. In this paperwork the way of transforming a preliminary gravimetric geoid into the system of orthometric leveling heights of Serbia network is presented.",
journal = "Informatics, Geoinformatics and Remote Sensing, Vol II (Sgem 2015)",
title = "Transformation of gravimetric geoid/quasigeoid in the system of orthometric/normal heights of Serbia leveling network",
pages = "601-593",
url = "https://hdl.handle.net/21.15107/rcub_grafar_660"
}

Odalović, O., Grekulović, S., Vasiljević, I., Todorović-Drakul, M.,& Popović, J.. (2015). Transformation of gravimetric geoid/quasigeoid in the system of orthometric/normal heights of Serbia leveling network. in Informatics, Geoinformatics and Remote Sensing, Vol II (Sgem 2015), 593-601.
https://hdl.handle.net/21.15107/rcub_grafar_660

Odalović O, Grekulović S, Vasiljević I, Todorović-Drakul M, Popović J. Transformation of gravimetric geoid/quasigeoid in the system of orthometric/normal heights of Serbia leveling network. in Informatics, Geoinformatics and Remote Sensing, Vol II (Sgem 2015). 2015;:593-601.
https://hdl.handle.net/21.15107/rcub_grafar_660 .

Odalović, Oleg, Grekulović, Sanja, Vasiljević, Ivana, Todorović-Drakul, Miljana, Popović, Jovan, "Transformation of gravimetric geoid/quasigeoid in the system of orthometric/normal heights of Serbia leveling network" in Informatics, Geoinformatics and Remote Sensing, Vol II (Sgem 2015) (2015):593-601,
https://hdl.handle.net/21.15107/rcub_grafar_660 .

TY  - JOUR
AU  - Odalović, Oleg
AU  - Joksimović, Danilo
AU  - Grekulović, Sanja
AU  - Todorović-Drakul, Miljana
AU  - Popović, Jovan
PY  - 2015
UR  - https://grafar.grf.bg.ac.rs/handle/123456789/685
AB  - This paper presents geometrically and physically defined height systems, along with their evaluation by the means of Global Navigation Satellite Systems (GNSS) and Global Geopotential Models (GGM). The paper defines ellipsoid heights as an instance of geometrically defined heights; with physically defined heights being represented by definitions of orthometric and normal heights. Methods of normal heights calculation by the means of ellipsoid heights are presented in detail, as determined using the GNSS and height anomalies calculated from the GGM application. Apart from the above, numerical part of the paper evaluates normal height values and compares them to their conditionally accurate values at 1073 points with relatively uniform distribution over the entire territory of Serbia. Conditionally accurate values had been determined by the means of classical geodetic terrestrial methods. Under the procedure of evaluating normal height values, GGM – GGM05C was used, as created in 2016 by the Center for Space Research, University of Texas at Austin. In order to evaluate the quality of applying the model above, data on normal heights evaluation were also presented, using the GGM EGM96, created in 1996 by the National Imagery and Mapping Agency (NIMA), Goddard Space Flight Center (GSFC – NASA) and Ohio State University, presently being the most commonly used model. The comparison above indicates that application of the GGM05C model provides 50 % greater quality of normal heights evaluations against the ones obtained using the EGM96 model.
AB  - U okviru rada prikazani su geometrijski i fizički definisani sistemi visina, kao i njihova ocena primenom globalnih navigacionih satelitskih sistema (GNSS) i globalnih geopotencijalnih modela (GGM). U radu je data definicija elipsoidnih visina kao predstavnika geometrijski definisanih visina, a u pogledu fizički definisanih visina prikazane su definicije ortometrijskih i normalnih visina. Detaljno su predstavljeni načini računanja normalnih visina primenom elipsoidnih visina, koje su određene primenom GNSS i anomalija visina koje slede iz primene GGM. Pored navedenog u numeričkom delu rada ocenjene su vrednosti normalnih visina i upoređene sa njihovim uslovno tačnim vrednostima i to u 1073 tačke koje su relativno pravilno raspoređene po čitavoj teritoriji Srbije. Uslovno tačne vrednosti određene su primenom klasičnih geodetskih terestričkih metoda. U postupku ocene vrednosti normalnih visina korišćen je GGM GGM05C koji je kreiran 2016. godine od strane Centra za kosmička istraživanja u Teksasu (Center for Space Research, University of Texas at Austin). U cilju ocene kvaliteta primene navedenog modela prikazani su i podaci ocene normalnih visina pri primeni GGM EGM96 koji je kreiran 1996. godine od strane Nacionalne agencije za digitalnu obradu slika i kartiranje (National Imagery and Mapping Agency - NIMA), Centra za kosmičke letove Nacionalne kosmičke agencije (Goddard Space Flight Center – GSFC - NASA) i američkog Univerziteta Ohajo (Ohio State University), koji do danas predstavlja najčešće korišćeni model. Iz navedenog upoređenja sledi da se primenom modela GGM05C dobijaju 50% kvalitetnije ocene normalnih visina od onih koje slede iz primene modela EGM96.
PB  - Srpsko geografsko društvo, Beograd
T2  - Glasnik Srpskog geografskog društva
T1  - Evaluation of normal heights by the means of global navigation satellite systems and global Geopotential Model
T1  - Ocena normalnih visina primenom globalnih navigacionih satelitskih sistema i globalnih geopotencijalnih modela
EP  - 124
IS  - 4
SP  - 103
VL  - 95
DO  - 10.2298/GSGD1504103O
ER  - 

@article{
author = "Odalović, Oleg and Joksimović, Danilo and Grekulović, Sanja and Todorović-Drakul, Miljana and Popović, Jovan",
year = "2015",
abstract = "This paper presents geometrically and physically defined height systems, along with their evaluation by the means of Global Navigation Satellite Systems (GNSS) and Global Geopotential Models (GGM). The paper defines ellipsoid heights as an instance of geometrically defined heights; with physically defined heights being represented by definitions of orthometric and normal heights. Methods of normal heights calculation by the means of ellipsoid heights are presented in detail, as determined using the GNSS and height anomalies calculated from the GGM application. Apart from the above, numerical part of the paper evaluates normal height values and compares them to their conditionally accurate values at 1073 points with relatively uniform distribution over the entire territory of Serbia. Conditionally accurate values had been determined by the means of classical geodetic terrestrial methods. Under the procedure of evaluating normal height values, GGM – GGM05C was used, as created in 2016 by the Center for Space Research, University of Texas at Austin. In order to evaluate the quality of applying the model above, data on normal heights evaluation were also presented, using the GGM EGM96, created in 1996 by the National Imagery and Mapping Agency (NIMA), Goddard Space Flight Center (GSFC – NASA) and Ohio State University, presently being the most commonly used model. The comparison above indicates that application of the GGM05C model provides 50 % greater quality of normal heights evaluations against the ones obtained using the EGM96 model., U okviru rada prikazani su geometrijski i fizički definisani sistemi visina, kao i njihova ocena primenom globalnih navigacionih satelitskih sistema (GNSS) i globalnih geopotencijalnih modela (GGM). U radu je data definicija elipsoidnih visina kao predstavnika geometrijski definisanih visina, a u pogledu fizički definisanih visina prikazane su definicije ortometrijskih i normalnih visina. Detaljno su predstavljeni načini računanja normalnih visina primenom elipsoidnih visina, koje su određene primenom GNSS i anomalija visina koje slede iz primene GGM. Pored navedenog u numeričkom delu rada ocenjene su vrednosti normalnih visina i upoređene sa njihovim uslovno tačnim vrednostima i to u 1073 tačke koje su relativno pravilno raspoređene po čitavoj teritoriji Srbije. Uslovno tačne vrednosti određene su primenom klasičnih geodetskih terestričkih metoda. U postupku ocene vrednosti normalnih visina korišćen je GGM GGM05C koji je kreiran 2016. godine od strane Centra za kosmička istraživanja u Teksasu (Center for Space Research, University of Texas at Austin). U cilju ocene kvaliteta primene navedenog modela prikazani su i podaci ocene normalnih visina pri primeni GGM EGM96 koji je kreiran 1996. godine od strane Nacionalne agencije za digitalnu obradu slika i kartiranje (National Imagery and Mapping Agency - NIMA), Centra za kosmičke letove Nacionalne kosmičke agencije (Goddard Space Flight Center – GSFC - NASA) i američkog Univerziteta Ohajo (Ohio State University), koji do danas predstavlja najčešće korišćeni model. Iz navedenog upoređenja sledi da se primenom modela GGM05C dobijaju 50% kvalitetnije ocene normalnih visina od onih koje slede iz primene modela EGM96.",
publisher = "Srpsko geografsko društvo, Beograd",
journal = "Glasnik Srpskog geografskog društva",
title = "Evaluation of normal heights by the means of global navigation satellite systems and global Geopotential Model, Ocena normalnih visina primenom globalnih navigacionih satelitskih sistema i globalnih geopotencijalnih modela",
pages = "124-103",
number = "4",
volume = "95",
doi = "10.2298/GSGD1504103O"
}

Odalović, O., Joksimović, D., Grekulović, S., Todorović-Drakul, M.,& Popović, J.. (2015). Evaluation of normal heights by the means of global navigation satellite systems and global Geopotential Model. in Glasnik Srpskog geografskog društva
Srpsko geografsko društvo, Beograd., 95(4), 103-124.
https://doi.org/10.2298/GSGD1504103O

Odalović O, Joksimović D, Grekulović S, Todorović-Drakul M, Popović J. Evaluation of normal heights by the means of global navigation satellite systems and global Geopotential Model. in Glasnik Srpskog geografskog društva. 2015;95(4):103-124.
doi:10.2298/GSGD1504103O .

Odalović, Oleg, Joksimović, Danilo, Grekulović, Sanja, Todorović-Drakul, Miljana, Popović, Jovan, "Evaluation of normal heights by the means of global navigation satellite systems and global Geopotential Model" in Glasnik Srpskog geografskog društva, 95, no. 4 (2015):103-124,
https://doi.org/10.2298/GSGD1504103O . .

TY  - CONF
AU  - Odalović, Oleg
AU  - Grekulović, Sanja
AU  - Todorović-Drakul, Miljana
PY  - 2015
UR  - https://grafar.grf.bg.ac.rs/handle/123456789/1313
PB  - Građevinski fakultet, Univerzitet u Beogradu, Beograd
C3  - Zbornik apstrakata i program / Kongres metrologa, Zlatibor, 12-15. oktobra 2015. godine
T1  - Analiza tačnosti podataka satelitske misije GOCE na teritoriji Republike Srbije
UR  - https://hdl.handle.net/21.15107/rcub_grafar_1313
ER  - 

@conference{
author = "Odalović, Oleg and Grekulović, Sanja and Todorović-Drakul, Miljana",
year = "2015",
publisher = "Građevinski fakultet, Univerzitet u Beogradu, Beograd",
journal = "Zbornik apstrakata i program / Kongres metrologa, Zlatibor, 12-15. oktobra 2015. godine",
title = "Analiza tačnosti podataka satelitske misije GOCE na teritoriji Republike Srbije",
url = "https://hdl.handle.net/21.15107/rcub_grafar_1313"
}

Odalović, O., Grekulović, S.,& Todorović-Drakul, M.. (2015). Analiza tačnosti podataka satelitske misije GOCE na teritoriji Republike Srbije. in Zbornik apstrakata i program / Kongres metrologa, Zlatibor, 12-15. oktobra 2015. godine
Građevinski fakultet, Univerzitet u Beogradu, Beograd..
https://hdl.handle.net/21.15107/rcub_grafar_1313

Odalović O, Grekulović S, Todorović-Drakul M. Analiza tačnosti podataka satelitske misije GOCE na teritoriji Republike Srbije. in Zbornik apstrakata i program / Kongres metrologa, Zlatibor, 12-15. oktobra 2015. godine. 2015;.
https://hdl.handle.net/21.15107/rcub_grafar_1313 .

Odalović, Oleg, Grekulović, Sanja, Todorović-Drakul, Miljana, "Analiza tačnosti podataka satelitske misije GOCE na teritoriji Republike Srbije" in Zbornik apstrakata i program / Kongres metrologa, Zlatibor, 12-15. oktobra 2015. godine (2015),
https://hdl.handle.net/21.15107/rcub_grafar_1313 .

TY  - JOUR
AU  - Janković, Ljiljana
AU  - Drakulić, Momčilo
AU  - Stanić, Miloš
AU  - Prodanović, Dušan
AU  - Vasilić, Željko
PY  - 2013
UR  - https://grafar.grf.bg.ac.rs/handle/123456789/493
AB  - This paper presents a general solutions for disposal of waste and atmospheric waters in the villages Blace and Brus, which were pre­pared under the IPA III component PPF4 - Project Preparation Facility 4, IPA 2010. Legislation relating to the discharge of water - EU Directives, including the Directive on Urban Waste Water, directs towards the selection of separation systems for the collection and disposal of waste and storm waters and treatment of waste waters in treatment plants before discharge to receiving waters. This is particularly important in terms of protecting downstream water flows and prevention of environmental degradation. Simulation models are built, separately for the used and atmospheric water, for the analysis of the existing sewer system and sizing of new. Models were made in the software package 3DNET, hydro information tool which incorporates terrain elevation data, the land use and the geometric data for the network pipes and channels.
AB  - U ovom radu su prikazana generalna rešenja odvođenja upotrebljene i atmosferske vode naselja Brus i Blace koji su pripremani u okviru IPA III komponente PPF4 - Project Preparation Facility 4, IPA 2010. Zakonska regulativa koja se odnosi na odvođenje upotrebljenih voda - Direktive EU, uključujući i Direktivu o gradskim otpadnim vodama, usmerava ka odabiranju separacionih sistema za prikupljanje i odvođenje upotrebljenih i atmosferskih voda i prečišćavanje upotrebljenih voda u postrojenjima za prečišćavanje pre ispuštanja u prijemnike. Ovo je posebno značajno sa aspekta zaštite nizvodnih vodotoka i sprečavanje degradiranja životne sredine. Za potrebe analize postojećih kanalizacionih mreža i dimenzionisanje novih, napravljeni su simulacioni modeli, odvojeno za upotrebljenu i atmosfersku vodu. Modeli su pravljeni u softverskom paketu 3DNet, hidroinformacionom alatu koji u sebi sjedinjuje visinske podatke o terenu, o nameni površina kao i geometrijske podatke o mreži cevi i kanala.
PB  - Udruženje za tehnologiju vode i sanitarno inžinjerstvo, Beograd
T2  - Voda i sanitarna tehnika
T1  - Display of general solutions for disposal of waste and storm waters in the villages Blace and Brus
T1  - Prikaz generalnih rešenja odvođenja upotrebljenih i kišnih voda naselja Brus i Blace
EP  - 38
IS  - 3
SP  - 31
VL  - 43
UR  - https://hdl.handle.net/21.15107/rcub_grafar_493
ER  - 

@article{
author = "Janković, Ljiljana and Drakulić, Momčilo and Stanić, Miloš and Prodanović, Dušan and Vasilić, Željko",
year = "2013",
abstract = "This paper presents a general solutions for disposal of waste and atmospheric waters in the villages Blace and Brus, which were pre­pared under the IPA III component PPF4 - Project Preparation Facility 4, IPA 2010. Legislation relating to the discharge of water - EU Directives, including the Directive on Urban Waste Water, directs towards the selection of separation systems for the collection and disposal of waste and storm waters and treatment of waste waters in treatment plants before discharge to receiving waters. This is particularly important in terms of protecting downstream water flows and prevention of environmental degradation. Simulation models are built, separately for the used and atmospheric water, for the analysis of the existing sewer system and sizing of new. Models were made in the software package 3DNET, hydro information tool which incorporates terrain elevation data, the land use and the geometric data for the network pipes and channels., U ovom radu su prikazana generalna rešenja odvođenja upotrebljene i atmosferske vode naselja Brus i Blace koji su pripremani u okviru IPA III komponente PPF4 - Project Preparation Facility 4, IPA 2010. Zakonska regulativa koja se odnosi na odvođenje upotrebljenih voda - Direktive EU, uključujući i Direktivu o gradskim otpadnim vodama, usmerava ka odabiranju separacionih sistema za prikupljanje i odvođenje upotrebljenih i atmosferskih voda i prečišćavanje upotrebljenih voda u postrojenjima za prečišćavanje pre ispuštanja u prijemnike. Ovo je posebno značajno sa aspekta zaštite nizvodnih vodotoka i sprečavanje degradiranja životne sredine. Za potrebe analize postojećih kanalizacionih mreža i dimenzionisanje novih, napravljeni su simulacioni modeli, odvojeno za upotrebljenu i atmosfersku vodu. Modeli su pravljeni u softverskom paketu 3DNet, hidroinformacionom alatu koji u sebi sjedinjuje visinske podatke o terenu, o nameni površina kao i geometrijske podatke o mreži cevi i kanala.",
publisher = "Udruženje za tehnologiju vode i sanitarno inžinjerstvo, Beograd",
journal = "Voda i sanitarna tehnika",
title = "Display of general solutions for disposal of waste and storm waters in the villages Blace and Brus, Prikaz generalnih rešenja odvođenja upotrebljenih i kišnih voda naselja Brus i Blace",
pages = "38-31",
number = "3",
volume = "43",
url = "https://hdl.handle.net/21.15107/rcub_grafar_493"
}

Janković, L., Drakulić, M., Stanić, M., Prodanović, D.,& Vasilić, Ž.. (2013). Display of general solutions for disposal of waste and storm waters in the villages Blace and Brus. in Voda i sanitarna tehnika
Udruženje za tehnologiju vode i sanitarno inžinjerstvo, Beograd., 43(3), 31-38.
https://hdl.handle.net/21.15107/rcub_grafar_493

Janković L, Drakulić M, Stanić M, Prodanović D, Vasilić Ž. Display of general solutions for disposal of waste and storm waters in the villages Blace and Brus. in Voda i sanitarna tehnika. 2013;43(3):31-38.
https://hdl.handle.net/21.15107/rcub_grafar_493 .

Janković, Ljiljana, Drakulić, Momčilo, Stanić, Miloš, Prodanović, Dušan, Vasilić, Željko, "Display of general solutions for disposal of waste and storm waters in the villages Blace and Brus" in Voda i sanitarna tehnika, 43, no. 3 (2013):31-38,
https://hdl.handle.net/21.15107/rcub_grafar_493 .