Unified Analysis Workshop, 10-12 July 2017, Paris The ILRS Products with ITRF2014/SLRF2014 V. Luceri, M.Pirri e-GEOS S.p.A., ASI/CGS - Matera E. Pavlis, M. Kuzmicz-Cieslak GEST/UMBC – Baltimore, MD G. Bianco Agenzia Spaziale Italiana, CGS - Matera Unified Analysis Workshop, 10-12 July 2017, Paris

ITRF2014 implementation status The ILRS ACs/CCs implemented the Post Seismic Deformation model in the SW for SLR data analysis, for combination and solution comparison/checking.  After the release of the official ITRF2014, the 1983-2014 ILRSA v61 was used to test the frame and compare with SLRF2008: Analysis of SSC residuals Analysis of Helmert parameters (Translations&Scale) The official ILRS solution with ITRF2014 started in June 2017

Site Coordinate Residuals wrms of SSC residuals – core sites 11.5 mm 5.3mm 11.4 mm 4.6mm

The updated ILRS daily product The update include ITRF2014, mean pole and variable gravity field

SLR sensitivity to the TRF datum 0.5 mm 1 mm 1.5 mm 5 mm

ILRSA Translations: Tx ITRF2014 Rate: (-0.00 ± 0.02) mm/yr Residual wrms= 3.63 mm ITRF2008 Rate: (0.01 ± 0.02) mm/yr Residual wrms= 3.70 mm

ILRSA Translations: Ty ITRF2014 Rate: (-0.06 ± 0.02) mm/yr Residual wrms= 3.24 mm ITRF2008 Rate: (-0.14 ± 0.02) mm/yr Residual wrms= 3.41 mm

ILRSA Translations: Tz ITRF2014 Rate: (0.12 ± 0.03) mm/yr Residual wrms= 6.27 mm ITRF2008 Rate: (0.34 ± 0.03) mm/yr Residual wrms= 6.53 mm

ILRSA Translations ITRF2014 DTRF2014 JTRF2014

ILRSA Scale ITRF2014 Rate: (-0.09 ± 0.01) mm/yr Residual wrms= 2.39 mm

ILRSA Scale JTRF2014 Rate: (-0.01 ± 0.01) mm/yr Residual wrms= 1.25 mm DTRF2014 Rate: (0.04 ± 0.01) mm/yr Residual wrms= 2.34 mm ITRF2014 Rate: (-0.09 ± 0.01) mm/yr Residual wrms= 2.39 mm

Station Systematic Error Modeling The ASC strategy was to limit application and estimation of biases to real events occurred and documented at the station Engineering bias report from CDDIS database and from the stations through SLRMail ILRS Data handling file adopted by the Anaysis Standing Committee listing: bias to be applied sites requiring bias estimation (to be kept at minimum) unrecoverable data to be edited Rapid, daily bias analysis report from the ILRS ACs Bias time series estimated from a multi-year solution

ILRS Pilot Project on systematic errors Weekly estimation of coordinates, EOP and range biases Time frame: 2005-2008 Data: L1 and L2 A priori frame: ITRF2008 2 time series: unique and separate range biases Available time series from 5 ACs ILRSA combined series

Combined range biases Herstmonceux LAGEOS LAGEOS-2 Data handling file: 7840 --- mm A 02:032:00000 07:042:00000 R -9.00

Impact on the site coordinates 3D coordinate residual WRMS

Impact on the scale Scale w.r.t. ITRF2008 Standard L1-2 bias Common bias Standard wmean = -4.64 mm Bias est. wmean = +2.31 mm Same results if using ITRF2014

Path forward Points to note: ILRS ASC approach Estimating the biases for all the sites together with the coordinates weakens the official products The 7-day estimation is a medium/long term monitoring, not a quick QC The medium/long term monitoring is essential to trace the range biases at centimeter level ILRS ASC approach make a table of biases using the time series of combined range biases from 1983 up to now apply the bias values in the table for the official ILRS products keep the table updated

Summary ITRF2014 tested and implemented in the ILRS processing chain Scale issue investigated in the ILRS Analysis Standing Committee with a Pilot Project. The ILRS data handling file with the range bias table to be updated Datum comparison made with DTRF2014 and JTRF2014: no apparent issue with the SLR scale