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Regulation of the Minister of Environment Tallinn 05 February 2004 No 4 Enforcement of geodetic system
(2) The geodetic system consists of:
§2 Geodetic reference system (1) The geodetic reference system is the European Terrestrial Reference System ETRS89, which is defined as following: 1) ETRS89 is, according to the Resolution 1 of the 1990 Symposium of the Subcommision for the European Reference Frame (EUREF) of the Internanational Association of Geodesy (IAG), coincident with the International Terrestrial Reference System (ITRS) of the International Earth Rotation and Reference Systems Service (IERS) at the epoch 1989.0 and fixed to the stable part of the Eurasian Plate. For the calculation of geodetic coordinates the ellipsoid GRS80 is used. 2) The ITRS reference system constitutes a set of prescriptions and conventions together with the modelling required to define origin, scale, orientation and time evolution of a conventional terrestrial reference system according to the 1996 conventions of IERS. 3) The ITRS reference system, updated and improved by IERS, is realized with the International Terrestrial Reference Frame (ITRF), which is a set of points with their geocentric rectangular coordinates. (2) The reference system ETRS89 is realized on the territory of Estonia as a set of coordinates of the geodetic network, the abbreviation of rectangular and geodetic coordinates of which is EUREF-EST97. (3) The Estonian geodetic network is divided according to the accuracy of measurements, monumentation of points and hierarchical structure of the network into I and II order networks and densification network. The points and the coordinates of the points of these networks serve as basis for other realisations of geodetic systems in Estonia. (4) The coordinates of geodetic network points at the epoch 1997.56 are based on the ITRS realisation ITRF96 and the measurements of I order geodetic network points, in calculations the methods defined by EUREF are used. (5) The coordinates of the I and II order geodetic networks and of the densification network are entered into the geodetic database of the Estonian Land Board. (6) In Estonia the coordinates EUREF-EST97 and the coordinates of the World Geodetic System’s (WGS84) realisation WGS84(G8873) are considered to be identical. WGS84 is defined as following: 1) WGS84 constitutes a set of prescriptions and conventions together with the modelling required to define origin, scale, orientation and time evolution of a conventional terrestrial reference system according to the 1996 conventions of IERS. 2) WGS84 is realized with a set of points with their geocentric rectangular coordinates WGS84(G8873). § 3 Plane rectangular coordinate system (1) The plane rectangular coordinate system L-EST97 is derived from the Lambert conical conformal map projection with two standard parallels LAMBERT-ESTONIA (abridged as LAMBERT-EST), the calculations of which have been done on the ellipsoid GRS80 using the following data: 1) Central meridian LC = 24°00’ E 2) First standard parallel BS = 58°00’ N 3) Second standard parallel BN = 59°20’ 4) Origin of geodetic coordinates B0 = 57°31’03’’.19415 N L0 = 24°00’ E 5) Origin of rectangular coordinates x0 = 6375 000 m yY0 = 500 000 m (2) The projection LAMBERT-EST is used for the calculation of plane rectangular coordinates L-EST97 from the geodetic coordinates EUREF-EST97. (1) The Estonian height system is the Baltic 1977 Height System (abridged in Estonia as BK77), which is defined with the following parameters: 1) The zero-point of height system coincides with the average of Kronstadt sea level measurements in 1825-1840. 2) The epoch of the height system is not defined. 3) The average system of Earth’s permanent tides is used. 4) The heights are calculated as normal heights. For the calculation of the normal gravity field Helmert’s gravity formula of 1901 is used. (2) On the territory of Estonia the Baltic 1977 Height System is realized with the heights of benchmarks of the levelling network. (3) The levelling network is divided according to the accuracy of measurements, monumentation of points and hierarchical structure of the network into I, II, III and IV order networks. The points of the above networks and their heights serve as basis for other realizations of the height network in Estonia. (4) The heights of benchmarks of the levelling network are based on the adjustment of the levelling network of the former Soviet Union, the epoch is undefined. (5) The heights of levelling network points are entered into the geodetic database of the Estonian Land Board. (6) The geoid model of Estonia is EST-GEOID2003. (7) The model EST-GEOID2003 is used for calculating the EUREF-EST97 ellipsoidal heights into BK77 heights in the conformity with the accuracy requirements. (8) The data of geoid model are entered into the geodetic database of the Estonian Land Board. §5 Gravimetric system (1) The Estonian gravimetric system is a system based on the 1988 standards of the International Absolute Gravity Base Station Network (IAGBN) developed by the II Working Group of the International Gravity Commission (IGC) of the International Association of Geodesy (IAG). (2) The realization of the gravimetric system on the territory of Estonia is a set of gravity values of the gravimetric network points GV-EST95. (3) The gravimetric network is divided according to the accuracy of measurements, monumentation of points and hierarchical structure of the network into I, II and III order networks. The points of the above networks and their gravity values serve as basis for other realizations of the gravimetric system in Estonia. (4) The gravity values of gravimetric network points at the epoch 1995.8 are based on the absolute gravity measurements of the I order gravity network points, which have been performed according to IAGBN standards. (5) The gravity values of gravimetric network points are entered into the geodetic database of the Estonian Land Board. §6 Implementation of geodetic system (1) The Estonian geodetic system is used for the performance of geodetic, gravimetric, and cartographic works in case these data will be entered into state and local governments’ databases. Plane rectangular coordinates L-EST97 are used for the maintenance of state and local governments’ databases. BK77 heights and GV-EST95 gravity values are entered into state and local governments’ databases, as occasion requires. (2) The implementation of the geodetic system does not extend to:
(3) The coordinates in the databases that are maintained in the conformity with international agreements shall be made available for the use in Estonia as transformations into L-EST97 plane rectangular coordinates by 1 June 2005 at the latest. (4) Institutions maintaining the state and local governments’ databases shall determine, in cooperation with the Estonian Land Board, the parameters between the coordinates of coordinate systems used so far and the coordinates of L-EST97. The geodetic system enacted with this Regulation shall be implemented in state and local governments’ databases by 1 June 2005 at the latest. Minister Secretary General Villu Reiljan Sulev Vare Yüklə 15,67 Kb. Dostları ilə paylaş:
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