DGFI has taken the responsibility for an ITRS Combination Centre within the International Earth Rotation and Reference Systems Service (IERS) since 2001.
The ITRS Combination Centre is responsible for the computation of terrestrial reference frame realizations (ITRF) through the combination of space geodetic data sets (GPS, SLR, VLBI, DORIS) provided by the corresponding techniques' services (IGS, ILRS, IVS, IDS). DGFI has computed the following realizations of the terrestrial reference system:
- ITRS Realization 2003
- ITRF2005 Solution of DGFI
- ITRS Realization 2008: DTRF2008
The computation of the International Terrestrial Reference Frame 2008 (DTRF2008) was completed in May 2010. DGFI2008 is an independent solution, based on the same input data as ITRF2008, which is computed by the IERS Combination Centre at IGN, Paris, and provided by the IERS Product Centre at IGN in May 2010. The difference between both solutions is the combination strategy: while a combination of solutions is performed at IGN, DGFI computation is based on the combination of normal equations.
The DTRF2008 is a global terrestrial reference frame containing the station coordinates of 559 GPS, 106 VLBI, 122 SLR and 132 DORIS stations. The reference epoch for station positions is 2005-01-01, 0:00 UTC. Earth orientation parameters (EOP), i.e., coordinates of the terrestrial and the celestial pole, UT1-UTC and length of day (LOD), are simultaneously solved with the station coordinates. The time series of EOP covers the period from 1983 until the end of 2008. The solution is available in different file formats at ftp.dgfi.badw.de/pub/DTRF2008.
Acknowledgement: The establishment of the ITRS Combination Centre at DGFI has been supported by the German Bundesministerium für Bildung und Forschung within the programme GEOTECHNOLOGIEN, Grant (IERS)03F0336C.
Seitz, M., D. Angermann, M. Bloßfeld, H. Drewes, M. Gerstl: The 2008 DGFI Realization of the ITRS: DTRF2008, accepted by J Geod, 2012-04-16
Seitz, M., D. Angermann, M. Bloßfeld, M. Gerstl, R. Heinkelmann, R. Kelm, H. Müller, Die Berechnung des Internationalen Terrestrischen Referenzrahmens ITRF 2008 am DGFI, zfv Zeitschrift für Geodäsie, Geoinformation und Landmanagement, 135, no. 2, 73-79, 2010.
Angermann, D., H. Drewes, M. Gerstl, M. Kruegel, B. Meisel: DGFI combination methodology for ITRF2005. Springer, IAG Symposia, Vol. 134, 11-16, doi:10.1007/978-3-642-00860-3_2, 2009.
Seitz M.: Kombination geodätischer Raumbeobachtungsverfahren zur Realisierung eines terrestrischen Referenzsystems, Reihe C 630, Deutsche Geodätische Kommission, München, 2009, ISBN 978-3-7696-5042-6