Global VLBI Solution IGG05R01 1 Institute of Geodesy and Geophysics (IGG), Vienna, Austria 2 German Geodetic Research Institute (DGFI), Munich, Germany Robert Heinkelmann 1, Johannes Boehm 1, Harald Schuh 1, and Volker Tesmer 2

2  general aim: contributions to future realizations of IVS and IERS combined products - TRF - CRF - EOP time series  special aim: investigations of dependencies between the long-term characteristics of - met data in VLBI Analysis - tropospheric parameters - station positions and velocities - scale factor and scale rate Motivation 4th IVS General Meeting

3  unconstrained simultaneous estimation of - source positions (VieCRF) - station positions and velocities (VieTRF) - Earth orientation parameters (VieEOP)  using OCCAM 6.1 (LSM) VLBI software and DOGS-CS for handling the normal equations 1  geodetic datum definitions: - VieCRF: NNR w.r.t. ICRF-Ext.1 using 199 stable sources - VieTRF: NNR+NNT w.r.t. ITRF2000 using 15 stations 1 the DOGS-CS software was developed at DGFI, Munich; thank you for provision IGG05R01 – General characteristics 4th IVS General Meeting

4  3,414,325 observations  1450 globally estimated parameters  2702 sessions in NGS-format  till IGG05R01 – General characteristics total number of sessions available in NGS-format IGG05R th IVS General Meeting

5 session criteria  minimal duration: 18h (no intensive sessions)  minimum of 3 stations  no sessions unreliable for the determination of EOP ( )  rms < 2 cm, fraction of outliers < 3.5 % station criteria  50 VLBI stations (of 136 out of ITRF2000)  no mobile stations (but TIGOCONC) source criteria  552 radio sources (of 667 out of ICRF-Ext. 1)  minimum of 3 observations per session  minimum of 3 sessions for global estimation of source position Criteria for the solution 4th IVS General Meeting

6 Estimated parameters with OCCAM  CRF: right ascension α, declination   TRF: positions X, Y, Z  EOP: nutation ,  , and ERP: Xp, Ẋp, Yp, Ẏp, dUT1, dUṪ1  tropospheric zenith delays: offset, PWLF with 1 hour interval, rates constrained with 10 mm/h  tropospheric gradients: offset constrained with 0.5 mm  clock parameters: offset, rate, and squared rate w.r.t. reference station + clock breaks (if necessary), PWLF with 1 hour interval, rates constrained with 30 mm/h 4th IVS General Meeting

7 Estimated parameters with DOGS-CS  CRF: right ascension α, declination   TRF: positions X, Y, Z, and velocities Ẋ, Ẏ, Ż discontinuities:GILCREEK| | earthquake TSUKUB32| | rail repair DSS65| | rail repair EFLSBERG| | rail repair MEDICINA| | rail repair DSS15| | earthquake MOJAVE12 | | earthquake NRAO85 3 | | unknown  EOP  tropospheric zenith delays  tropospheric gradients  clock parameters reduced 4th IVS General Meeting

8 Analysis settings and geophysical models  outlier elimination: data snooping with threshold of 3.5  mapping function: VMF  cutoff elevation angle : 5°  a-priori zenith delays from homogenized pressure records  axis offsets: taken from the Analysis Coordinator webpage (  model of relativity: ‘consensus model’  ephemerides: DE405/LE405  model of nutation: MHB 2000 (without FCN)  solid earth tides: IERS Conv  ocean loading: GOT00p2 (provided by H.G. Scherneck)  no a-priori tropospheric gradients  no atmospheric loading, snow loading, …  no antenna thermal deformation 4th IVS General Meeting

9 VieCRF* w.r.t. ICRF-Ext.1   [hour]   [deg]   [mas]  *cos(  ) [mas] 1.1 %>3 mas 0.8 %>3 mas 4th IVS General Meeting * sources with >3 sessions

10 VieEOP w.r.t. IERS-C04 MHB2000 model was used without free core nutation part!  : signal with period ~ 430 d (free core nutation) shift: mas rate: mas/y  : signal with period ~ 430 d (free core nutation) shift: mas rate: mas/y 4th IVS General Meeting

VieEOP w.r.t. IERS-C04 ITRF2000, ICRF-Ext.1 and EOP-C04 are from different solutions! dXp: shift: mas rate: mas/y dYp: shift: mas rate: mas/y dUT1: shift:  s rate:  s/y 11 4th IVS General Meeting

12IGG05R01 VTRF2005 VieTRF 4th IVS General Meeting

13 Vertical component w.r.t. ITRF2000 VieTRF VTRF2003 VTRF2005 DGFI-TRF The 15 datum stations 4th IVS General Meeting

14 Helmert parameters from VieTRF into ITRF2000  12 regularly used stations (IVS 2005) epoch   [  as] ± ± 240   [  as] ± ± 247   [  as] ± ± 236  X [mm] 1.5 ± ± 6.3  Y [mm] -2.6 ± ± 6.2  Z [mm] 1.0 ± ± 6.0 scale [ppb] 0.81 ± ± 0.94 scale [mm]* ALGOPARK FORTLEZA GILCREEK HARTRAO HOBART26 KOKEE MATERA NYALES20 SESHAN25 TSUKUB32 WESTFORD WETTZELL  scale rate is ppb/y, 0.02 mm*/y * at Earth radius 4th IVS General Meeting

16 Earthquake near Concepci ó n, superconducting gravity meter jump of +26  Gal (free-air gradient ≈ mgal/m) =>  up= ̶ 84 mm model 2: constant rate =>  up= ̶ 7.7 mm model 1: two rates =>  up= +0.5 mm 4th IVS General Meeting no comparable jump in up component! instrumental effect?!

17 Summary and outlook  IGG05R01, the Vienna global solution, is already of acceptable quality  it can be improved by  using met data from NWM  extending the number of stations  extending the number of sources (outside the ICRF-Ext.1)  adding sub-sets of 24h type of sessions, in particular the large VLBA sessions  applying atmospheric loading corrections  applying corrections for the thermal deformation of telescopes  applying a-priori atmospheric gradients  applying new mapping functions VM1 (instead of VMF)  optimizing soft + hard constraints 4th IVS General Meeting

contacts: R. Heinkelmann Thank you for your attention! end 4th IVS General Meeting The coauthors are greatly acknowledged for their scientific advice. Project is funded by