Impact of Different ITRS Realizations on VLBI Combined EOP and Scale
In this paper we investigate the impact of using the three ITRS realizations DTRF2014, ITRF2014, and JTRF2014 as a priori TRF for the VLBI combination on EOP and scale. The scale factor between the IVS routine combined solution and DTRF2014, ITRF2014, and JTRF2014 shows a significant offset of −0.59 ppb with respect to ITRF2014 and of 0.19 ppb with respect to JTRF2014. No significant offset was found for the DTRF2014-based solution. The investigation of the EOP of all four TRF-based solutions (DTRF2014-, ITRF2014-, JTRF2014- and VTRF2015q2-based) shows specific effects when comparing to the reference time series IERS 14C04, IGS, and ILRS. Relative to the VTRF2015q2-based solution, x-pole differences with respect to the DTRF2014-based solution (positive trend) and JTRF2014-based solution (scatter and negative trend), as well as an offset concerning the y-pole for all three TRF-based solutions with an additional scatter for the JTRF2014-based solution are recognized. No significant differences were found for pole rates, nutation, and LOD, but using ITRF2014 or JTRF2014 leads to marginal larger scatter with respect to the VTRF-based EOP series for LOD. In addition, a significant impact was found when comparing dUT1. All three TRF-based solutions show a significant offset comparing to IERS 14C04, whereas no offset is detected for the VTRF2015q2-based solution.
KeywordsEarth orientation parameters ITRS realizations Scale factor VLBI
We thank Vincenza Luceri for providing the ILRS combined EOP time series for our comparisons.
- Bachmann S, Thaller D (2017) ITRS realizations in the framework of ITRF2014: impact of different TRF parameterizations on VLBI combined products. In: Haas R, Elgered G (eds) Proceedings of the 23rd European VLBI Group for Geodesy and Astrometry Working Meeting, pp 157–161. ISBN: 978-91-88041-10-4Google Scholar
- Bizouard C, Lambert S, Becker O, Richard JY (2017) Combined solution C04 for earth rotation parameters consistent with international terrestrial reference frame 2014. Observatoire de Paris, SYRTE, 61 av. de l’Observatoire, Paris. http://hpiers.obspm.fr/eoppc/eop/eopc04/C04.guide.pdf
- Seitz M, Bloßfeld M, Angermann D, Schmid R, Gerstl M, Seitz F (2016) The new DGFI-TUM realization of the ITRS: DTRF2014 (data). Deutsches Geodätisches Forschungsinstitut, Munich (2016). https://doi.org/10.1594/PANGAEA.864046