International cooperation and technology transfer

Fras, Mojca Kosmatin

Bibliographic data

Monograph

Persistent identifier:: 856490555

Author:: Fras, Mojca Kosmatin

Title:: International cooperation and technology transfer

Sub title:: Ljubljana, Slovenia, February 2 - 5, 2000 : proceedings of the workshop

Scope:: VI, 163 Seiten

Year of publication:: 2000

Place of publication:: London

Publisher of the original:: RICS Books

Identifier (digital):: 856490555

Illustration:: Illustrationen, Diagramme

Language:: English

Usage licence:: Attribution 4.0 International (CC BY 4.0)

Publisher of the digital copy:: Technische Informationsbibliothek Hannover

Place of publication of the digital copy:: Hannover

Year of publication of the original:: 2016

Document type:: Monograph

Collection:: Earth sciences

Chapter

Title:: NATIONAL AND MODERN GEODETIC COORDINATE SYSTEMS IN SLOVENIA. Bojan Stopar, Miran Kuhar

Document type:: Monograph

Structure type:: Chapter

148 NATIONAL AND MODERN GEODETIC COORDINATE SYSTEMS IN SLOVENIA Bojan Stopar, Miran Kuhar University of Ljubljana, Faculty of Civil and Geodetic Engineering - Geodetic Department, Jamova 2, Ljubljana, Slovenia 1SPRS WG VI/3 and WG IV/3 KEYWORDS: reference frame, reference system, astrogeodetic network, geoid, transformation, collocation ABSTRACT The paper presents the condition of the official coordinate system in Slovenia. The inherent errors and distorsions in the astrogeodetic network of Slovenia make it unsuitable for today's requirements which not only include national mapping and cadastral purposes, but also scientific and safety purposes such as earthquake prediction, crustal dynamics and land subsidence. The results of different transformation procedures between the astrogeodetic network and global coordinate system (ETRS89) shows all the drawbacks of existing coordinate frame. Now with the advent of new technologies such as GPS, it is becoming of increasing importance that such accurate surveying measurements could be incorporated into an existing coordinate frame without degrading the measurements itself. It is obvious that such control network must be realized in terms of a stable and consistent coordinate frame which is of a global nature. In order to implement such a modern threedimensional coordinate system country should have all reference system (height and horizontal position) well defined and up-to-date. One of the prerequisites for that is also an accurate geoid - the reference surface for height determination. COORDINATE SYSTEMS AND COORDINATE FRAMES The purpose of a reference frame is to provide the means to materialize a reference system so that it can be used for the quantitative description of positions and motions on the Earth (terrestrial frames), or of celestial bodies, including the Earth, in space (celestial frames). In geodesy and astronomy only two basic coordinate systems are needed: a Conventional Inertial System (CIS), which in some 'prescribed' way is attached to extragalactic celestial radio sources, to serve as a reference for the motion of a Conventional Terrestrial System (CTS). It moves and rotates with the Earth and is also attached in some 'prescribed' way to a number of dedicated observatories operating on the Earth's surface. Both of above mentioned basic coordinates systems are defined and maintained by International Earth Rotation Service (IERS) and are known as: • International Celestial Reference System (ICRS), • International Terrestrial Reference System (ITRS). At its 23rd General Assembly in August 1997, the IAU decided that, as from 1 January 1998, the IAU celestial reference system shall be the International Celestial Reference System (ICRS), in replacement of the FK5 (Fundamental Katalog 5). The origin of the ICRS is at the barycentre of the solar system. The directions of its axes are fixed with respect to the distant quasars to better than 0.02 mas (milliarc of second). The ICRS is realized by estimates of the coordinates of a set of quasars, the International Celestial Reference Frame (ICRF). The ICRF consists of a catalogue of equatorial coordinates of 608 extragalactic radio sources derived from about 1.6 million observations accumulated by a worldwide network over 1979- 1995. The accuracy of the definition of the ICRF axes is estimated to be 0.02 mas. The origin of the International Terrestrial Reference System (ITRS) is at the centre of mass of the whole Earth, including the oceans and the atmosphere. Its length unit is the metre (SI). The orientation of its axes is consistent with that of the BIH System at 1984.0 within ±3 milliarcseconds. Its time evolution in orientation is such that it has no residual rotation relative to the Earth's crust. The ITRS is realized by estimates of the coordinates and velocities of a set of observing stations. Realizations of the ITRS are produced by the Terrestrial Frame Section of the IERS Central Bureau under the name International Terrestrial Reference Frame (ITRF), which consist of lists of coordinates (and velocities) for a selection of IERS sites (tracking stations or related ground markers). Currently, ITRF-yy is published annually in IERS Technical Notes. The numbers (yy) following the designation ITRF specify the last year whose data were used in the formation of the frame. Hence ITRF97 designates the frame of coordinates and velocities constructed in 1997 using all of the IERS data available through 1996. EUROPEAN TERRESTRIAL REFERENCE SYSTEM 1989 ETRS 89 The I AG has established during its Vancouver General Assembly (1987) a subcommission called 'EUREF' for the European Reference Frame of the Commission X on Continental Networks. EUREF took over the works done by the RETRIG subcommision which as a final result produced combined adjustment of terrestrial data of national's primary triangulation and space derived data covering western Europe under the name ED87 (European Datum 1987). The primary goal of EUREF was to take full advantage of available space geodetic techniques to realize a truly threedimensional and mostly accurate control network which would be the basic realization of a new terrestrial system for Europe. The implementation of this goal were possible by availability of the ITRS, established by the IERS, which is accepted worldwide. The existence of the rather dense network of primary sites over the Europe belonging to the IERS network assured the possibility for the connection of the new sistem to the existing terrestrial system. In such a system station positions in Europe have a common motion of the order of one centimeter per year. The system adopted by EUREF is the European Terrestrial Reference System 89 (ETRS 89) and is coincident

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