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1
Content available On accuracy of current geopotential models estimated through comparison of quasi-geoid models and GPS/levelling data
Novak P., Kostelecky J., Klokocnik J.
Reports on Geodesy
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2006
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z. 1/76
245-251
EN
Gravity-dedicated satellite missions CHAMP and GRACE provide accurate data that can be inverted into geopotential coefficients forming global geopotential models (GGM). Through an estimation process, mean square errors of these coefficients can be elvaluated. In most cases, even the entire variance-covariance matrices are computed. However, these errors are only formaI and do not represent weIl the actual accuracy of estimated coefficients, thus also of various gravity field parameters synthesized from these coefficients. For this reason validation procedures for the new GGMs are being sought since the classical validation methocts reached their limits. This article discusses the validation procedure of the GGM through its comparison with idependent data estimated at selected GPS/leveIling stations over the area of Central Europe. Due to a different spectral content of height anomalies synthesized from the GGM and of those derived from combination of ellipsoidal and normal heights at selected points of the European Vertical Reference Network, the GGM-based low-frequency height anomaly is completed for a missing higth-frequency component based on high resolution and high accuracy ground gravity and elevation data. The methodology is also applied on a set of GPS/leveIling stations in the Czech Republic. In accordance with previous validation tests of GGMs based on data of crossover altimetry, obtained results indicate that the current GGMs estimated from single/dual-sateIlite data seem to have significant problems namely with low-order and degree coefficients.
2
Content available GPS antenna calibration at the Geodetic Observatory Pecny, Czech Republic
Filler V., Kostelecky J.
Reports on Geodesy
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2006
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z. 1/76
233-244
3
Content available remote Quasigeoids for the territory of the Czech Republic and their testing
Kostelecky J., Kostelecky I., Pesek I., Simek J., Svabensky O., Weigel J., Zeman A.
Reports on Geodesy
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2002
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z. 1/61
47-52
EN
Development of the quasigeoids on the territory of the Czech Republic with succesive icorporating of new gravimetric observations on the territory of the CR and data gained from the territories of neighbouring countries. Estimations of accuracy of individual models. Testing the models by employment of GPS/levelling results on the profile with maximum change of quasigeoid elevation and by comparing with the GPS/levelling results at test areas.
4
Content available remote On determination of GPS antenna phase centres at the geodetic observatory Pecny
Kostelecky J.
Reports on Geodesy
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2002
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z. 1/61
145-152
EN
Higher accuracy requirements for results of GPS measurements (mainly for geodynamic purposes) introduce a problem of determination of phase centres of used GPS antennas. The method of field calibration with rotation of the antenna is a suitable compromise between financial requirements and accuracy of results. This method was applied to antennas used in the GPS permanent service at the GOPE station, Czech Republic. Results were used to explain some phenomena in time series of the station coordinates. Jumps in horizontal components of the time series were explained by differences in phase centres` positions. An introduces milimetre differences in phase centres` positions and the snow induces centimetre changes in the vertical component of phase centres` positions.
5
Content available remote Center of Earth`s Dynamics Research (CEDR) - a joint venture towards research in geosciences in CEI
Kostelecky J., Vondrak J., Zeman A., Kalvoda J., Schenk V.
Reports on Geodesy
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2002
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z. 1/61
93-99
6
Content available remote On some operational aspects of permanent GPS stations
Kostelecky J.
Reports on Geodesy
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2001
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z. 4/59
51-56
7
Content available remote Detailed geoidal profile on the territory of Czech Republic and its interpretation
Kostelecky J., Pesek I., Svabensky O., Weigel J., Zeman A.
Reports on Geodesy
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2001
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z. 2/57
51-55
8
Content available remote Relative changes of station positions on the territory of Europe from the results of space geodesy techniques and an attempt at their geodynamic interpretation
Kostelecky J., Zeman A.
Reports on Geodesy
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2000
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z. 6/52
111-117
9
Content available remote Geometrical interpretation of the quasigeoid on the territory of the Czech Republic
Kostelecky J., Zeman A.
Reports on Geodesy
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1998
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z. 9/39
163-173
EN
The surface of the local quasigeoid, constructed at the Research Institute of Geodesy, Topography and Cartography on the basis of heterogeneous data (astronomy, gravimetry) is considered as geometrical surface. For that surface the metric tensor, Christoffel symbols, Gaussian and mean curvatures were computed. The results are correlated with geotectonic structure and other geophysical phenomena of the territory of the Czech Republic.
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