Analysis of the time series of station coordinates - a comparison of the network and PPP approach

Based on the example of fourteen selected permanent GNSS stations of the EPN (EUREF Permanent Network) the differences of time variations of coordinates – velocities – resulting from the network and PPP (Precise Point Positioning) solution are studied. In both approaches the coordinates are determinated using the Bernese software version 5.2. The time series analysis is made using the modified Vaníček´s method. The comparison shows that the results provided by the two methods cannot be accepted as statistically consistent.Web of Science12213312

A 200 km suspected impact crater Kotuykanskaya near Popigai, Siberia, in the light of new gravity aspects from EIGEN 6C4, and other data

We provide arguments in favour of impact origin of a 200 km suspected impact crater Kotuykanskaya near Popigai, Siberia, Russia. We use the gravity aspects (gravity disturbances, the Marussi tensor of the second derivatives of the disturbing geopotential, the gravity invariants and their specific ratio, the strike angles and the virtual deformations), all derived from the combined static gravity field model EIGEN 6C4, with the ground resolution of about 10 km and a precision of about 10 milliGals. We also use the magnetic anomalies from the model EMAG2 and emphasize the evidence of much deeper sources in the suspected area, constraining the impact origin of this structure.Web of Science101art. no. 609

Global and regional seasonal variations of the geoid detected by grace

Since 2002, the US-German GRACE (Gravity Recovery and Climate Experiment) mission has been providing a precise survey of the Earth's time-variable gravity field, with unprecedented temporal and spatial sampling. GRACE time-variable gravity fields provide a means of measuring the temporal and spatial variations of mass redistribution within the Earth system. The GRACE mission has started a new era in studying a series of geophysical problems ranging from deep Earth structure to tracking mass redistribution on and near the surface of the Earth. Time variability of the gravity field presented here is based on the transformation of “monthly gravity field models” to the geoid. We show the changes caused by the global water cycle and land hydrology.Web of Science10329128

Gso Projection, BRST Cohomology and Picture-Changing in N=2 String Theory

We investigate in detail the critical $N{=}2$ fermionic string with and without a global ${\bf Z}_2$ twist. An analysis of BRST cohomology shows that twisted sectors contain massless `spacetime' fermions which are {\it non-local\/} with respect to the standard massless boson. However, two distinct GSO projections exist, one (untwisted) retaining merely the usual boson and its spectral-flow partner, the other (twisted) yielding two fermions and one boson, on the massless level. The corresponding chiral BRST-invariant vertex operators are constructed in certain pictures, and their fusion and picture-changing are investigated, including the construction of inverse picture-changing operators. The $N{=}2$ `spacetime supersymmetry' generators are {\it null\/} operators, since the twisted massless states fail to interact. The untwisted three- and four-point functions are recalculated at tree-level.Comment: 42 pages, LaTeX, no figures, 115 kb, ITP-UH-05/94, DESY 94-104 (extensive revision and expansion of earlier version

Results of geodetic measurements during the January 2010 Efpalio earthquakes at the western tip of the Gulf of Corinth, Central Greece

The results of geodetic GNSS measurements on the EYPA station (bult by INSU CNRS from France) in Corinth Gulf in Greece are analyzed. Data is analyzed in the time interval before and after the earthquakes, which occured in January 2010. Results confirm vertical and horizontal co-seismic shifts of EYPA station of the order of 4 cm and 1 cm.Web of Science9330129

Geometrické charakteristiky hladinových ploch

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Implementace SEVESO II direktivy

Import 20/04/2006Prezenční výpůjčkaVŠB - Technická univerzita Ostrava. Fakulta bezpečnostního inženýrství. Katedra (040) bezpečnostního management

Testing of GNSS multipath in different observational conditions at one stationary station

The aim of this paper is the analysis of temporal changes in multipath propagation errors on the pseudorange GNSS signal used for positioning, and its behavior during the calendar year (the quality of signal depends on e.g. foliage of trees, changes reflectivity surfaces due to rain or snow, etc.). The analysis was performed on data measured on a stationary point at Geodetic Observatory Pecny at Ondrejov, where one day was chosen as a constant time unit. Given the relatively highly unfavorable configuration of the experiment, RMS value of multipath is up to 60 cm on C1 and 40 cm on C2. These values vary with different weather conditions between 10 and 20 cm.Web of Science14442942