Global VLBI Solution IGG05R01 1 Institute of Geodesy and Geophysics (IGG), Vienna, Austria 2 German Geodetic Research Institute (DGFI), Munich, Germany

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

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 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


4

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


5

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


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


7

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


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 (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


9

VieCRF* w.r.t. ICRF-Ext.1

[hour]

[hour]

[deg]

[deg]

[

mas]

*c

os(

) [

mas]

1.1 %>3 mas

0.8 %>3 mas


* sources with >3 sessions

10

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


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


12IGG05R01

VTRF2005VieTRF


13

Vertical component w.r.t. ITRF2000

VieTRFVTRF2003VTRF2005DGFI-TRF

The 15datumstations


14

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


16

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


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 constraints4th IVS General

Meeting

contacts: R. Heinkelmann

[email protected]

Thank you for your attention!

end4th IVS General Meeting

The coauthors are greatly acknowledgedfor their scientific advice.Project 16992 is funded by

Documents

Global VLBI Solution IGG05R01 1 Institute of Geodesy and Geophysics (IGG), Vienna, Austria 2 German Geodetic Research Institute (DGFI), Munich, Germany