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Global VLBI Solution IGG05R01

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

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Global VLBI Solution IGG05R01

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  1. Robert Heinkelmann1, Johannes Boehm1, Harald Schuh1, and Volker Tesmer2 Global VLBI Solution IGG05R01 1 Institute of Geodesy and Geophysics (IGG), Vienna, Austria 2 German Geodetic Research Institute (DGFI), Munich, Germany

  2. Motivation • generalaim: contributions to future realizations of IVS and IERS combined products- TRF- CRF- EOP time series • specialaim: 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 4th IVS General Meeting 2

  3. IGG05R01 – General characteristics • 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 equations1 • 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 4th IVS General Meeting 3

  4. IGG05R01 – General characteristics total number ofsessions availablein NGS-format 4490 2702 IGG05R01 • 3,414,325 observations • 1450 globally estimated parameters • 2702 sessions in NGS-format • 1984-01-04 till 2005-11-28 4th IVS General Meeting 4

  5. Criteria for the solution • session criteria • minimal duration: 18h (no intensive sessions) • minimum of 3 stations • no sessions unreliable for the determination of EOP (http://vlbi.geod.uni-bonn.de/IVS-AC/data/exclude.html) • 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 4th IVS General Meeting 5

  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 6

  7. Estimated parameters with DOGS-CS • CRF: right ascension α, declination  • TRF: positions X, Y, Z, and velocities Ẋ, Ẏ, Żdiscontinuities: GILCREEK | 02-11-03 | earthquake TSUKUB32 | 99-04-01 | rail repair DSS65 | 97-04-15 | rail repair EFLSBERG | 96-10-01 | rail repair MEDICINA | 96-06-01 | rail repair DSS15 | 92-06-27 | earthquake MOJAVE12 | 92-06-27 | earthquake NRAO85 3 | 90-12-01 | unknown • EOP • tropospheric zenith delays • tropospheric gradients • clock parameters reduced 4th IVS General Meeting 7

  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 homogenizedpressure records • axis offsets: taken from the Analysis Coordinator webpage (http://giub.geod.uni-bonn.de/vlbi/IVS-AC/data/axis-offsets.html) • model of relativity: ‘consensus model’ • ephemerides: DE405/LE405 • model of nutation: MHB 2000 (without FCN) • solid earth tides: IERS Conv. 2003 • 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 8

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

  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: - 0.012 mas rate: +0.019 mas/y : signal with period ~ 430 d (free core nutation) shift: -0.036 mas rate: -0.010 mas/y 4th IVS General Meeting 10

  11. VieEOP w.r.t. IERS-C04 ITRF2000, ICRF-Ext.1 and EOP-C04 are from different solutions! dXp: shift: -0.212 mas rate: -0.005 mas/y dYp: shift: 0.108 mas rate: 0.037 mas/y dUT1: shift: 0.776 s rate: 0.158 s/y 4th IVS General Meeting 11

  12. VTRF2005 VieTRF IGG05R01 4th IVS General Meeting 12

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

  14. Helmert parameters from VieTRF into ITRF2000 • 12 regularly used stations (IVS 2005) ALGOPARK FORTLEZA GILCREEK HARTRAO HOBART26 KOKEE MATERA NYALES20 SESHAN25 TSUKUB32 WESTFORD WETTZELL • scale rate is 0.0029 ppb/y, 0.02 mm*/y * at Earth radius 4th IVS General Meeting 14

  15. Earthquake near Concepción, 2004-05-03 superconducting gravity meter jump of +26Gal (free-air gradient ≈ -0.3086 mgal/m) => up= ̶ 84 mm model 1: two rates=> up= +0.5 mm model 2: constant rate =>up= ̶ 7.7 mm instrumental effect?! no comparable jump in up component! 4th IVS General Meeting 16

  16. 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 17

  17. Thank you for your attention! The coauthors are greatly acknowledgedfor their scientific advice.Project 16992 is funded by contacts: R. Heinkelmann rob@mars.hg.tuwien.ac.at end 4th IVS General Meeting

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