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Institute of Geodesy and Geophysics, Vienna University of Technology Vienna, February 2004

Subgroup "Data Analysis" of Working Group 3 VLBI2010. Harald Schuh. Institute of Geodesy and Geophysics, Vienna University of Technology Vienna, February 2004. 1. Geodetic/astrometric data analysis. 1.1 Data analysis: Improved models. loading corrections (ocean, atmosphere, hydrosphere, ...).

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Institute of Geodesy and Geophysics, Vienna University of Technology Vienna, February 2004

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  1. Subgroup "Data Analysis" of Working Group 3 VLBI2010 Harald Schuh Institute of Geodesy and Geophysics, Vienna University of Technology Vienna, February 2004

  2. 1. Geodetic/astrometric data analysis 1.1 Data analysis: Improved models • loading corrections (ocean, atmosphere, hydrosphere, ...)

  3. Atmospheric loading Maximum range and variance invertical crustal displacement during 1994-1998 (mm) due to changesin atmospheric surface pressure. (van Dam et al., 2002)

  4. Hydrological loading Maximum range and variance in vertical crustal displacement during 1994-1998 (mm) due to changesin total continental water storage. (van Dam et al., 2002)

  5. Snow loading Vertical displacementsdue to snow cover atAlgonquin Park. (Estermann and Schuh, 2003)

  6. 1. Geodetic/astrometric data analysis 1.1 Data analysis: Improved models • loading corrections (ocean, atmosphere, hydrosphere, ...) • antenna deformation and local displacements

  7. 1. Geodetic/astrometric data analysis Antenna deformation Direct measurement • Invar wire or rod systems monitor height differences between antenna foundations and elevation axes • Currently installed at Onsala and Wettzell

  8. 1. Geodetic/astrometric data analysis Antenna deformation Direct measurement (Zernecke, 1999)

  9. 1. Geodetic/astrometric data analysis Antenna deformation Direct measurement • Invar wire or rod systems monitor height differences between antenna foundations and elevation axes • Currently installed at Onsala and Wettzell Thermal model • Model using antenna dimensions, expansion coefficients, measured temperatures • Reasonable agreement with invar measurements at Onsala and Wettzell (using mean daily temperatures)

  10. 1. Geodetic/astrometric data analysis Antenna deformation Thermal model with hf, hp, hv, hs ... dimensions of the telescops f, a ............. expansion coefficients T0 ................. reference temperature tf, ta ......... time delay (Nothnagel, 1995; IERS Conventions 2003)

  11. 1. Geodetic/astrometric data analysis 1.1 Data analysis: Improved models • loading corrections (ocean, atmosphere, hydrosphere, ...) • antenna deformation and local displacements • implementation of IAU Resolutions 2000 and of IERS Conventions (2003)

  12. IAU Resolutions 2000 Earth orientation parameters (precession, nutation, GST) in the FK5 (Capitaine, 2002)

  13. IAU Resolutions 2000 Earth orientation parameters(E, d, ) referred to the ICRS (Capitaine, 2002)

  14. 1. Geodetic/astrometric data analysis 1.1 Data analysis: Improved models • loading corrections (ocean, atmosphere, hydrosphere, ...) • antenna deformation and local displacements • implementation of IAU Resolutions 2000 and of IERS Conventions (2003) • source structure effects (needs in fact a kind of Service)

  15. VLBI images of 2200 + 420 at X band (top) and S band (bottom) for 10 successive epochs, spanning the period 1997.1-1998.6. The maps are aligned horizontally according to the northern structural component and are spaced linearly according to their observing epochs. The scale is in milliarcseconds. (Charlot, 2002)

  16. 1. Geodetic/astrometric data analysis 1.1 Data analysis: Improved models • loading corrections (ocean, atmosphere, hydrosphere, ...) • antenna deformation and local displacements • implementation of IAU Resolutions 2000 and of IERS Conventions (2003) • source structure effects (needs in fact a kind of Service) • phase delay solutions for all baseline lengths

  17. 1. Geodetic/astrometric data analysis Phase delay solutions Progress has been made on resolving phase delay ambiguities on all baselines(e.g. L. Petrov) • ~70% of observations can be successfully resolved • Baseline length repeatabilities from phase delay solutions are not improved except for short baselines (< 5 km) More analysis of phase delays is required • to determine possible systematic instrumental effects • to understand significance of instrascan variations

  18. 1. Geodetic/astrometric data analysis 1.1 Data analysis: Improved models • loading corrections (ocean, atmosphere, hydrosphere, ...) • antenna deformation and local displacements • implementation of IAU Resolutions 2000 and of IERS Conventions (2003) • source structure effects (needs in fact a kind of Service) • phase delay solutions for all baseline lengths • improve stochastic model (a priori sigmas, correlations between observables, ...)

  19. variances  (Tesmer, 2004)

  20. 1. Geodetic/astrometric data analysis (2) 1.2 Data analysis: new strategies • Robust and Reliable VLBI Solutions • Consistency of TRF, EOP and CRF • Intra-VLBI Combinations of Complete Solutions • Investigations of Differences in Analysis Software Packages • Robust and Reliable VLBI Solutions • Consistency of TRF, EOP and CRF • Intra-VLBI Combinations of Complete Solutions • Robust and Reliable VLBI Solutions • Consistency of TRF, EOP and CRF • Robust and Reliable VLBI Solutions

  21. 1. Geodetic/astrometric data analysis 1.3 Automation of the VLBI Data Analysis Procedure Goal: development of an automatic VLBI analysis tool to achieve VLBI results in near real-time. Step 1: Structured Model of the VLBI Data Analysis Procedure • processing strategy of the VLBI data analysis • for each step of the data analysis identify - tasks to be performed - parameterization to be selected - models to be used - approach to perform the tasks - evaluation criteria to evaluate the results - error sources causing unsatisfactory results - methods to correct for faults

  22. 1. Geodetic/astrometric data analysis 1.3 Automation of the VLBI Data Analysis Procedure Step 1:Structured Model of the VLBI Data Analysis Procedure establish a Standardization Group on VLBI Data Analysis (proposed by W. Schwegmann)

  23. 1. Geodetic/astrometric data analysis 1.3 Automation of the VLBI Data Analysis Procedure Step 2: implement the structured model within the existing software establish a VLBI Data Analysis Software Automation Group (proposed by W. Schwegmann)

  24. 2. Atmosphere, ancillary data & models 2.1 Use of numerical weather models for • IMF … Isobaric Mapping Functions (Niell, 2001) • VMF … Vienna Mapping Funktions (Boehm and Schuh, 2003, 2004)

  25. Vienna Mapping Functions (VMF) from ECMWF data Wettzell (Boehm and Schuh, 2003, 2004)

  26. 2. Atmosphere, ancillary data & models 2.1 Use of numerical weather models for • IMF … Isobaric Mapping Functions (Niell, 2001) • VMF … Vienna Mapping Funktions (Boehm and Schuh, 2003, 2004) • gradients 2.2 Use of other instruments • WVR • radiosondes • ... • WVR

  27. 3. New goals to be aimed at by VLBI • contribution to climatology

  28. (Boehm et al., 2003)

  29. 3. New goals to be aimed at by VLBI • contribution to climatology • galactic rotation • relativistic effects • subdiurnal variations and episodic effects in the EOP • contribution to climatology • galactic rotation • relativistic effects • contribution to climatology • galactic rotation

  30. High resolution polar motion during CONT02

  31. High resolution polar motion during CONT02 (Nastula et al., 2004)

  32. 3. New goals to be aimed at by VLBI • contribution to climatology • galactic rotation • relativistic effects • subdiurnal variations and episodic effects in the EOP • contribution to Earthquake research • ... • contribution to climatology • galactic rotation • relativistic effects • subdiurnal variations and episodic effects in the EOP • contribution to Earthquake research • ...

  33. 4. New VLBI configurations and observing systems • Space VLBI (VSOP-2 and Radioastron) • Space VLBI (VSOP-2 and Radioastron) • observation of satellites transmitting S/X-band • ...

  34. Members of WG 3 Subgroup “Data Analysis” Johannes Boehm Sergei Bolotin Roger Capallo Gunnar Elgered Gerald Engelhardt Ruediger Haas Thomas Hobiger Ryuichi Ichikawa Dan MacMillan Shigeru Matsuzaka Arthur Niell Axel Nothnagel Harald Schuh (Chair) Wolfgang Schwegmann Ojars Sovers Volker Tesmer Oleg Titov

  35. THANK YOU FOR YOUR ATTENTION!

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