GPS MEASUREMENTS OF THE GEOTECTONIC RECENT
MOVEMENTS IN EAST SLOVAKIA
Prof. Vladimir SEDLAK, Slovak Republic
Key words: GPS, 3D transformations, topocentric
coordinate system, free adjustment, adjustment with constraints,
deformation teststatistics.
Abstract
The paper deals with transformation procedures observed GPS (Global
Positioning System) data from the World Geodetic System WGS-84 into
the national geodetic grid datum S-UTCN (System of United
Trigonometric Cadaster Network) and Baa. (The Baltic Sea after
adjustment). GPS measurements are situated into the geodetic network
in the Košice-Valley for a purpose of deformation surveying
geotectonic recent movements in the East-Slovak regions. Adjustment
with constraints and free adjustment are applied at determining
coordinates of the geodetic network points.
Transformation from WGS-84 into S-UTCN is the most frequently by
means of using the 7-element Helmert transformation with using three
identical points. Geodetic network was adjusted by two ways. In a case
when datum parameters are absolutely accuracy then an adjustment with
constraints is considered; in a case when datum parameters are
determined with a concrete accuracy, what has also an influence on an
accuracy of adjusted parameters except on measured accuracy, then a
free adjustment is considered.
The GPS measurements are realised on points of the geodetic network
(GN) localised in the Kosice-Valley (Slovakia). The aim of these
measurements is determining recent geotectonic movements in the urban
agglomeration of Kosice-city. 3D coordinates of the network points
determined from satellite navigation present a realisation result of
the solved scientific project at the Department of Geodesy and
Geophysics of the Technical University of Kosice since 1997.
GPS measurements are periodically realised twice a year (spring and
autumn). Altogether, 17 points of GN are measured by means of using
the GPS static method. A priority of the chosen static method for our
measurements is above all a high accuracy in determining point
positions which is conditioned by longer period of measurement on a
determined point (cca 45 minutes). The determined GN points are solved
by double GPS vector technology always regarding two reference points,
i.e. three GPS receivers are used for measurements. These points are
placed so that the territories in which some geotectonic movements are
presupposed according to geologists. The main tectonic fault in the
Kosice-Valley, according to which two expressive geological faults of
the Earth ground blocks should move, is assumed in the north-south
direction along the river Hornad. The secondary tectonic faults of
smaller extent are in the direction perpendicular to the Hornad fault,
i.e. in the east-west direction. These secondary tectonic faults are
mutually parallel.
Three double-frequency GPS receivers Sokkia GRS 2100 were used to
measurement. Adjustment of observed data was realised by the firm
software Prism ver 2.1 Sokkia. Coordinates of all points in GN were
transformed from WGS-84 into a plane coordinate system S-UTCN, which
is obligatory coordinate system for realisation of geodetic works in
Slovakia. The non-linear rotary matrix method was applied to the
adjustment. After transformation, the coordinates were consecutively
adjusted by an adjustment with constraints.
For a purpose of deformation consideration in the monitoring
network the coordinate differences are subjected to the teststatistic
hypotheses. A size of deformations is presented by the deformation
vectors on the individual network points. Modelling deformations in
the Kosice-Valley is based on GIS data by means of using the MicroSoft
and Kokes software.
BIOGRAPHICAL NOTE
Vladimir Sedlak is associate professor on geodesy and
engineering surveying at the Technical University of Kosice,
Department of Geodesy and Geophysics, Slovakia. He graduated on mine
surveying and geodesy at TU Kosice in 1980. In 1987 he obtained PhD.
on mine surveying. He is member of FIG (Commission 4), Presidium ISM
and General Assembly CLGE.
CONTACT
Assoc. Prof. Vladimir Sedlak, MSc., PhD.
Technical University
Department of Geodesy and Geophysics
Park Komenskeho 19
SK-043 84 Kosice
SLOVAKIA
Tel. + 421 95 6022 916
Fax + 421 95 6336 618
E-mail: sedlak@tuke.sk
23 March 2001
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