caa a22 4500 60616216X CHVBK 20210128100638.0 cr unu---uuuuu 210128e20150101xx s 000 0 eng 10.1007/s10291-013-0361-5 doi (NATIONALLICENCE)springer-10.1007/s10291-013-0361-5 Galileo orbit determination using combined GNSS and SLR observations [Elektronische Daten] [S. Hackel, P. Steigenberger, U. Hugentobler, M. Uhlemann, O. Montenbruck] The first two Galileo In-Orbit Validation satellites were launched in October 2011 and started continuous signal transmission on all frequencies in early 2012. Both satellites are equipped with two different types of clocks, namely rubidium clocks and hydrogen masers. Based on two test periods, the quality of the Galileo orbit determination based on Global Navigation Satellite System (GNSS) and Satellite Laser Ranging (SLR) observations is assessed. The estimated satellite clock parameters are used as quality indicator for the orbits: A bump at orbital periods in the Allan deviation indicates systematic errors in the GNSS-only orbit determination. These errors almost vanish if SLR observations are considered in addition. As the internal consistency is degraded by the combination, the offset of the SLR reflector is shifted by +5cm, resulting in an improved orbit consistency as well as accuracy. Another approach to reduce the systematic errors of the GNSS-only orbit determination employs constraints for the clock estimates with respect to a linear model. In general, one decimeter orbit accuracy could be achieved. Springer-Verlag Berlin Heidelberg, 2014 Satellite orbits nationallicence Global Navigation Satellite System (GNSS) nationallicence Satellite Laser Ranging (SLR) nationallicence Galileo In-Orbit Validation (IOV) nationallicence Hackel S. Institut für Astronomische und Physikalische Geodäsie (IAPG), Technische Universität München (TUM), Munich, Germany aut Steigenberger P. Institut für Astronomische und Physikalische Geodäsie (IAPG), Technische Universität München (TUM), Munich, Germany aut Hugentobler U. Institut für Astronomische und Physikalische Geodäsie (IAPG), Technische Universität München (TUM), Munich, Germany aut Uhlemann M. Helmholtz-Zentrum Potsdam, Deutsches GeoForschungsZentrum (GFZ), Potsdam, Germany aut Montenbruck O. German Space Operations Center (GSOC), German Aerospace Center (DLR), Oberpfaffenhofen, Germany aut GPS Solutions Springer Berlin Heidelberg 19/1(2015-01-01), 15-25 1080-5370 19:1<15 2015 19 10291 https://doi.org/10.1007/s10291-013-0361-5 text/html Onlinezugriff via DOI BK010053 XK010053 XK010000 Metadata rights reserved Springer special CC-BY-NC licence nationallicence 1 research-article jats NATIONALLICENCE NATIONALLICENCE NL-springer NATIONALLICENCE 856 40 https://doi.org/10.1007/s10291-013-0361-5 text/html Onlinezugriff via DOI NATIONALLICENCE 700 1- Hackel S. Institut für Astronomische und Physikalische Geodäsie (IAPG), Technische Universität München (TUM), Munich, Germany aut NATIONALLICENCE 700 1- Steigenberger P. Institut für Astronomische und Physikalische Geodäsie (IAPG), Technische Universität München (TUM), Munich, Germany aut NATIONALLICENCE 700 1- Hugentobler U. Institut für Astronomische und Physikalische Geodäsie (IAPG), Technische Universität München (TUM), Munich, Germany aut NATIONALLICENCE 700 1- Uhlemann M. Helmholtz-Zentrum Potsdam, Deutsches GeoForschungsZentrum (GFZ), Potsdam, Germany aut NATIONALLICENCE 700 1- Montenbruck O. German Space Operations Center (GSOC), German Aerospace Center (DLR), Oberpfaffenhofen, Germany aut NATIONALLICENCE 773 0- GPS Solutions Springer Berlin Heidelberg 19/1(2015-01-01), 15-25 1080-5370 19:1<15 2015 19 10291