global vlbi solution igg05r01 1 institute of geodesy and geophysics (igg), vienna, austria 2 german...
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Global VLBI Solution IGG05R01
1 Institute of Geodesy and Geophysics (IGG), Vienna, Austria
2 German Geodetic Research Institute (DGFI), Munich, Germany
Robert Heinkelmann1, Johannes Boehm1, Harald Schuh1, and Volker Tesmer2
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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
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unconstrained simultaneous estimation of - source positions (VieCRF)- station positions and velocities (VieTRF) - Earth orientation parameters (VieEOP)
using OCCAM 6.1 (LSM) VLBI softwareand 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
IGG05R01 – General characteristics
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3,414,325 observations 1450 globally estimated parameters 2702 sessions in NGS-format 1984-01-04 till 2005-11-28
IGG05R01 – General characteristics
total number ofsessions availablein NGS-format
IGG05R01
4490
2702
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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
Criteria for the solution
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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
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Estimated parameters with DOGS-CS
CRF: right ascension α, declination TRF: positions X, Y, Z, and velocities Ẋ, Ẏ, Ż
discontinuities: GILCREEK | 02-11-03 | earthquake TSUKUB32 | 99-04-01
| rail repairDSS65 | 97-04-15 | rail
repairEFLSBERG | 96-10-01 | rail repairMEDICINA | 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
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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 (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
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VieCRF* w.r.t. ICRF-Ext.1
[hour]
[hour]
[deg]
[deg]
[
mas]
*c
os(
) [
mas]
1.1 %>3 mas
0.8 %>3 mas
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* sources with >3 sessions
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VieEOP w.r.t. IERS-C04MHB2000 model was used without free core nutation part!
:signal with period ~ 430 d(free core nutation)shift: - 0.012 masrate: +0.019 mas/y
:signal with period ~ 430 d(free core nutation)shift: -0.036 masrate: -0.010 mas/y
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VieEOP w.r.t. IERS-C04ITRF2000, ICRF-Ext.1 and EOP-C04 are from different solutions!
dXp:shift: -0.212 masrate: -0.005 mas/y
dYp:shift: 0.108 masrate: 0.037 mas/y
dUT1:shift: 0.776 srate: 0.158 s/y
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12IGG05R01
VTRF2005VieTRF
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Vertical component w.r.t. ITRF2000
VieTRFVTRF2003VTRF2005DGFI-TRF
The 15datumstations
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Helmert parameters from VieTRF into ITRF2000
12 regularly used stations (IVS 2005)
epoch 2000 2010
[as]
-37.4 ± 151 112 ± 240
[as]
-66.6 ± 155 -238 ± 247
[as]
-51.4 ± 148 -82.4 ± 236
X [mm] 1.5 ± 4.0 -2.1 ± 6.3
Y [mm] -2.6 ± 3.9 -1.5 ± 6.2
Z [mm] 1.0 ± 3.8 -0.9 ± 6.0
scale [ppb] 0.81 ± 0.59 0.84 ± 0.94
scale [mm]*
5.2 5.4
ALGOPARKFORTLEZAGILCREEKHARTRAOHOBART26KOKEEMATERANYALES20SESHAN25TSUKUB32WESTFORDWETTZELL
scale rate is 0.0029 ppb/y, 0.02 mm*/y * at Earth radius
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Earthquake near Concepción, 2004-05-03
superconducting gravity meter jump of +26Gal (free-air gradient ≈ -0.3086 mgal/m)=> up= ̶ 84 mm
model 2: constant rate => up= ̶ 7.7 mm
model 1: two rates=> up= +0.5 mm
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no comparable jump in up component!
instrumental effect?!
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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 constraints4th IVS General
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contacts: R. Heinkelmann
Thank you for your attention!
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The coauthors are greatly acknowledgedfor their scientific advice.Project 16992 is funded by