HR: 1400h
AN: G43B-03    [Abstracts]
TI: ERP-Variations on Time Scales Between Hours and Months Derived From GNSS Observations
AU: Weber, R
EM: rweber@mars.hg.tuwien.ac.at
AF: Institute of Geodesy and Geophysics, University of Technology, Vienna, Gusshausstrasse 27-29, Vienna, A-1040, Austria
AU: Englich, S
EM: senglich@mars.hg.tuwien.ac.at
AF: Institute of Geodesy and Geophysics, University of Technology, Vienna, Gusshausstrasse 27-29, Vienna, A-1040, Austria
AU: * Mendes Cerveira, P
EM: mendes@mars.hg.tuwien.ac.at
AF: Institute of Geodesy and Geophysics, University of Technology, Vienna, Gusshausstrasse 27-29, Vienna, A-1040, Austria
AB: Current observations gained by the space geodetic techniques, especially VLBI, GPS and SLR, allow for the determination of Earth Rotation Parameters (ERPs - polar motion, UT1/LOD) with unprecedented accuracy and temporal resolution. This presentation focuses on contributions to the ERP recovery provided by satellite navigation systems (primarily GPS). The IGS (International GNSS Service), for example, currently provides daily polar motion with an accuracy of less than 0.1mas and LOD estimates with an accuracy of a few microseconds. To study more rapid variations in polar motion and LOD we established in a first step a high resolution (hourly resolution) ERP-time series from GPS observation data of the IGS network covering the year 2005. The calculations were carried out by means of the Bernese GPS Software V5.0 considering observations from a subset of 113 fairly stable stations out of the IGS05 reference frame sites. From these ERP time series the amplitudes of the major diurnal and semidiurnal variations caused by ocean tides are estimated. After correcting the series for ocean tides the remaining geodetic observed excitation is compared with variations of atmospheric excitation (AAM). To study the sensitivity of the estimates with respect to the applied mapping function we applied both the widely used NMF (Niell Mapping Function) and the VMF1 (Vienna Mapping Function 1). In addition, based on computations covering two months in 2005, the potential improvement due to the use of additional GLONASS data will be discussed.
DE: 1220 Atmosphere monitoring with geodetic techniques (6952)
DE: 1239 Earth rotation variations
DE: 1240 Satellite geodesy: results (6929, 7215, 7230, 7240)
SC: Geodesy [G]
MN: 2007 Joint Assembly