Abstract
The CONT02 campaign is of great interest for studies combining very long baseline interferometry (VLBI) with other space-geodetic techniques, because of the continuously available VLBI observations over 2 weeks in October 2002 from a homogeneous network. Especially, the combination with the Global Positioning System (GPS) offers a broad spectrum of common parameters. We combined station coordinates, Earth orientation parameters (EOPs) and troposphere parameters consistently in one solution using technique- specific datum-free normal equation systems. In this paper, we focus on the analyses concerning the EOPs, whereas the comparison and combination of the troposphere parameters and station coordinates are covered in a companion paper in Journal of Geodesy. In order to demonstrate the potential of the VLBI and GPS space-geodetic techniques, we chose a sub-daily resolution for polar motion (PM) and universal time (UT). A consequence of this solution set-up is the presence of a one-to-one correlation between the nutation angles and a retrograde diurnal signal in PM. The Bernese GPS Software used for the combination provides a constraining approach to handle this singularity. Simulation studies involving both nutation offsets and rates helped to get a deeper understanding of this singularity. With a rigorous combination of UT1–UTC and length of day (LOD) from VLBI and GPS, we showed that such a combination works very well and does not suffer from the systematic effects present in the GPS-derived LOD values. By means of wavelet analyses and the formal errors of the estimates, we explain this important result. The same holds for the combination of nutation offsets and rates. The local geodetic ties between GPS and VLBI antennas play an essential role within the inter-technique combination. Several studies already revealed non-negligible discrepancies between the terrestrial measurements and the space-geodetic solutions. We demonstrate to what extent these discrepancies propagate into the combined EOP solution.
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References
Altamimi Z, Sillard P, Boucher C (2002) ITRF2000: A new release of the International Terrestrial Reference Frame for Earth science applications. J Geophys Res 107(B10):2214, doi:10.1029/2001JB000561
Altamimi Z, Boucher C, Willis P (2005) Terrestrial reference frame requirements within GGOS perspective. J Geodyn 40(4,5):363–374, doi:10.1016/j.jog.2005.06.002
Andersen PH (2000) Multi-level arc combination with stochastic parameters. J Geod 74(7,8):531–551, doi:10.1007/ s001900000115
Angermann D, Drewes H, Krügel M, Meisel B, Gerstl M, Kelm R, Müller H, Seemüller W, Tesmer V (2004) ITRS Combination Center at DGFI: a terrestrial reference frame realization 2003. Deutsche Geodätische Kommission, Reihe B, Heft Nr. 313, Munich
Brockmann E (1997) Combination of solutions for geodetic and geophysical applications of the global positioning system (GPS). PhD Thesis. Geodätisch-Geophysikalische Arbeiten in der Schweiz, Band 55. Available at: ftp://ftp.unibe.ch/aiub/papers/ebdiss.pdf
Dill R, Rothacher M (2003) IERS analysis campaign to align EOP to ITRF2000 / ICRF. In: Observation of the system earth from space, status seminar at the Bavarian State Mapping Agency (BLVA), Munich, 12–13 June 2003, Programme and Abstracts, GEOTECHNOLOGIEN Science Report No. 3, Koordinierungsbüro GEOTECHNOLOGIEN, Potsdam, ISSN 1619–7399
Gambis D (1986) On the possibility of detecting some terms of the diurnal polar motion by the study of satellite orbits. Adv Space Res 6(9):33–36, doi:10.1016/0273-1177(86)90347-9
Gambis D (2004) Monitoring Earth orientation using space- geodetic techniques: state-of-the-art and prospective. J Geod 78(4,5):295–303, doi:10.1007/s00190-004-0394-1
Goupillaud P, Grossmann A, Morlet J (1984) Cycle-octave and related transforms in seismic signal analysis. Geoexploration 23(1):85–102, doi:10.1016/0016-7142(84)90025-5
Gross RS (2000) Combinations of Earth-orientation measurements SPACE97, COMB97, and POLE97. J Geod 73(12): 627–637, doi:10.1007/s001900050001
Gross RS, Eubanks TM, Steppe JA, Freedman AP, Dickey JO, Runge TF (1998) Kalman-filter-based approach to combining independent Earth-orientation series. J Geod 72(4):215–235, doi:10.1007/s001900050162
Heflin MB (2003) IGS reference site candidates. IGSMAIL-4281. http://www.igscb.jpl.nasa.gov/mail/igsmail/2003/ msg00059.html
Hefty J, Rothacher M, Springer T, Weber R, Beutler G (2000) Analysis of the first year of Earth rotation parameters with a sub-daily resolution gained at the CODE processing center of the IGS. J Geod 74(6):479–487, doi:10.1007/s001900000108
Herring TA, Dong D (1994) Measurement of diurnal and semidiurnal rotational variations and tidal parameters of Earth. J Geophys Res 99(B9):18051–18071, doi:10.1029/94JB00341
Hugentobler U, Dach R, Fridez P, Meindl M (eds) (2005) Bernese GPS Software Version 5.0. Astronomical Institute of the University of Berne, Switzerland. Draft version available at: http://www.bernese.unibe.ch/docs/DOCU50draft.pdf
Krügel M, Thaller D, Tesmer V, Schmid R, Rothacher M, Angermann D (2006) Tropospheric parameters: Combination studies based on homogeneous input data. J Geod (submitted)
McCarthy DD, Petit G (2004) IERS conventions 2003. IERS technical note No. 32. Verlag des Bundesamts für Kartographie und Geodäsie, Frankfurt am Main
Moritz H, Mueller II (1987) Earth rotation: theory and observation. Ungar Publishing Company, New York, ISBN 0-8044-4671-7
Ray J, Altamimi Z (2005) Evaluation of co-location ties relating the VLBI and GPS reference frames. J Geod 79(4,5):189–195, doi:10.1007/s00190-005-0456-z
Ray J, Kouba J, Altamimi Z (2005) Is there utility in rigorous combinations of VLBI and GPS Earth orientation parameters? J Geod 79(9):505–511, doi:10.1007/s00190-005-0007-7
Rothacher M, Beutler G, Herring TA, Weber R (1999) Estimation of nutation using the Global Positioning System. J Geophys Res 104(B3):4835–4859, doi:10.1029/1998JB900078
Thaller D, Rothacher M (2003) Comparison and combination of GPS, VLBI and SLR solution series. In: Observation of the system Earth from space, status seminar at the Bavarian State Mapping Agency (BLVA), Munich, 12–13 June 2003, Programme and Abstracts, GEOTECHNOLOGIEN Science Report No. 3, Koordinierungsbüro GEOTECHNOLOGIEN, Potsdam, ISSN 1619–7399
Thaller D, Krügel M, Angermann D, Rothacher M, Schmid R, Tesmer V (2005) Combination Studies Using the CONT02 Campaign. In: Behrend D, Baver K (eds) International VLBI service for geodesy and astrometry 2004 annual report, NASA/TP-2005-212772. NASA Goddard Space Flight Center, Greenbelt, MD
Thaller D, Krügel M, Tesmer V, Rothacher M, Schmid R, Angermann D (2006) Combination of Earth Orientation Parameters. In: Proceedings of the IERS Workshop on Combination, held at GFZ Potsdam, 10–11 October 2005, Bundesamt für Kartographie und Geodäsie, Frankfurt am Main (in press)
Thomas C, MacMillan DS (2003) CORE operation center report. In: Vandenberg NR, Baver KD (eds) International VLBI service for geodesy and astrometry 2002 annual report, NASA/TP-2003-211619. NASA Goddard Space Flight Center, Greenbelt, MD
Thomas C, MacMillan DS (2006) CORE operation center report. In: Behrend D, Baver KD (eds) International VLBI service for geodesy and astrometry 2005 annual report, NASA/TP-2006-214136. NASA Goddard Space Flight Center, Greenbelt, MD
Titov O, Tesmer V, Böhm J (2004) OCCAM V 6.0 software for VLBI data analysis. In: Vandenberg N, Baver K (eds) IVS 2004 General meeting proceedings, NASA/CP-2004-212255. NASA Goddard Space Flight Center, Greenbelt, MD
Watkins MM, Eanes RJ (1994) Diurnal and semidiurnal variations in Earth orientation determined from LAGEOS laser ranging. J Geophys Res 99(B9):18073–18079, doi:10.1029/94JB00805
Yaya P (2002) Apport des combinaisons de techniques astrométriques et géodésiques à l’estimation des paramètres d’orientation de la terre. PhD thesis, Observatoire de Paris
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Thaller, D., Krügel, M., Rothacher, M. et al. Combined Earth orientation parameters based on homogeneous and continuous VLBI and GPS data. J Geod 81, 529–541 (2007). https://doi.org/10.1007/s00190-006-0115-z
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DOI: https://doi.org/10.1007/s00190-006-0115-z