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A. M. Finkelstein A. V. Ipatov S. G. Smolentsev V. G. Grachev I. A. Rakhimov Z. M. Malkin 《Astronomy Letters》2003,29(10):667-673
We present the results of our processing of the first observations of extragalactic radio sources obtained with the eight-element International VLBI Network, which includes the Svetloe Russian Radio Astronomy Observatory equipped with a Mark 3A recording terminal. Our observations and their processing yielded highly accurate coordinates (in meters) of the Svetloe Observatory in the ITRF 2000 system: X = 2730173.854 ± 0.002, Y = 1562442.668 ± 0.004, Z = 5529969.069 ± 0.007. We also show that including the Svetloe Observatory in the International Network led to an appreciable improvement in the accuracy of determining the Earth’s rotation parameters (microarcseconds for the coordinates of the pole and nutation angles, microseconds for Universal Time): Xp = ?154683 ± 77, Yp = 361809 ± 59, UT1-UTC = ?325162.9 ± 2.5, Δψ = ?53147 ± 114, Δε = ?2286 ± 47. 相似文献
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Zinovy Malkin 《Journal of Geodesy》2017,91(7):839-848
Three combined celestial pole offset (CPO) series computed at the Paris Observatory (C04), the United States Naval Observatory (USNO), and the International VLBI Service for Geodesy and Astrometry (IVS), as well as six free core nutation (FCN) models, were compared from different perspectives, such as stochastic and systematic differences, and FCN amplitude and phase variations. The differences between the C04 and IVS CPO series were mostly stochastic, whereas a low-frequency bias at the level of several tens of \(\upmu \)as was found between the C04 and USNO CPO series. The stochastic differences between the C04 and USNO series became considerably smaller when computed at the IVS epochs, which can indicate possible problems with the interpolation of the IVS data at the midnight epochs during the computation of the C04 and USNO series. The comparison of the FCN series showed that the series computed with similar window widths of 1.1–1.2 years were close to one another at a level of 10–20 \(\upmu \)as, whereas the differences between these series and the series computed with a larger window width of 4 and 7 years reached 100 \(\upmu \)as. The dependence of the FCN model on the underlying CPO series was investigated. The RMS differences between the FCN models derived from the C04, USNO, and IVS CPO series were at a level of approximately 15 \(\upmu \)as, which was considerably smaller than the differences among the CPO series. The analysis of the differences between the IVS, C04, and USNO CPO series suggested that the IVS series would be preferable for both precession-nutation and FCN-related studies. 相似文献
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The spectroscopic red shifts of seven optical objects whose coordinates coincide with those of radio sources in the IVS (International
VLBI Service for Geodesy and Astrometry) program list are determined from observations with the 6-m BTA telescope at the Special
Astrophysical Observatory (SAO) of the Russian Academy of Sciences. A comparison of these spectra and red shifts with data
in the radio frequency range shows that four of the objects discussed here are correctly identified, while the other three
require further study. The distances to the radio sources derived from our measurements yield more accurate estimates of the
cosmological model parameters than those based on the proper motions of these objects derived from geodesic VLBI observations. 相似文献
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Zinovy Malkin 《Journal of Geodesy》2011,85(9):617-622
Very Long Baseline Interferometry (VLBI) Intensive sessions are scheduled to provide operational Universal Time (UT1) determinations
with low latency. UT1 estimates obtained from these observations heavily depend on the model of the celestial pole motion
used during data processing. However, even the most accurate precession- nutation model, IAU 2000/2006, is not accurate enough
to realize the full potential of VLBI observations. To achieve the highest possible accuracy in UT1 estimates, a celestial
pole offset (CPO), which is the difference between the actual and modelled precession-nutation angles, should be applied.
Three CPO models are currently available for users. In this paper, these models have been tested and the differences between
UT1 estimates obtained with those models are investigated. It has been shown that neglecting CPO modelling during VLBI UT1
Intensive processing causes systematic errors in UT1 series of up to 20 μas. It has been also found that using different CPO models causes the differences in UT1 estimates reaching 10 μas. Obtained results are applicable to the satellite data processing as well. 相似文献
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Z. M. Malkin 《Astronomy Reports》2014,58(6):415-425
Corrections to the IAU 2000/2006 parameters of the theory of precession and nutation are calculated using five different series—two individual series and three combined series that have been used in the literature for this purpose. A comparison of the sets of corrections obtained using the different datasets indicates significance systematic differences between them, which often substantially exceed the corresponding random errors. At the same time, existing studies have usually used data obtained from one or two series chosen by the authors without special justification. When refining the theory of precession and nutation, it is necessary to consider and compare various available series of VLBI data if one wishes to reduce the systematic errors in an improved model. 相似文献
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Astronomy Reports - Two possible sources of random and systematic errors of a new method for determining the parameters of the relative orientation of the catalogs of positions of extragalactic... 相似文献
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Astronomy Reports - An Erratum to this paper has been published: https://doi.org/10.1134/S1063772922020032 相似文献