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Introduction to VieVS 2.3
Andreas Hellerschmied David Mayer
AVN Training School, 22 February – 08 March 2016, Hartebeesthoek Radio Observatory, South Africa
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What is VieVS?
• VieVS = Vienna VLBI Software • State-of-the-art VLBI data analysis software for geodetic applications
– Main geodetic products: EOPs, station coordinates (TRF), source coordinates (CRF), etc.
– Many further estimates: geodynamic and atmospheric parameters (ZWD), etc. • Written in MATLAB • Developed at the Department of Geodesy and Geoinformation (Research
Group Advanced Geodesy) since 2008, Technische Universität Wien (TU Wien)
Current reference: Böhm J., S. Böhm, T. Nilsson, A. Pany, L. Plank, H. Spicakova, K. Teke, H. Schuh (2012). The New Vienna VLBI Software VieVS. Proceedings of the 2009 IAG Symposium, Series: International Association of Geodesy Symposia. Vol. 136. Geodesy for Planet Earth. Steve Kenyon, Maria Christina Pacino and Urs Marti (Eds.). ISBN 978-3-642-20337-4. pp. 1007-1011. DOI: 10.1007/978-3-642-20338-1_126 .
Why did we develop VieVS?
• Important that there exist several different types of VLBI analysis software – CALC/SOLVE (NASA, GSFC), DOGS_CS (DGFI), OCCAM, etc.
• Different software packages can validate each other. Helps identifying bugs etc.
• We want to have a VLBI software which is easy to use: – BSc, MSc, and PhD students can easily learn it and use it – Should be easy to add new models etc. for special investigations – Graphical User Interface (GUI) – Should have a clear structure
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Who did develop VieVS?
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Former & current members of the VLBI group at the Vienna University of Technology:
+ contributions from external partners from international Universities worldwide
VieVS development
• Development started in 2008 • Current Version 2.3 was released in December 2015 • Currently registered users from 49 institutions worldwide
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• Advantages: – Easy to use – Very convenient IDE (code editor, debugging tools, etc.) – Easy to change source code – Lots of predefined functions/toolboxes (plotting tools, etc.) – MATLAB is available on all major operating systems (Windows,
Linux/UNIX, Mac OS)
• Disadvantages: – MATLAB is an expensive commercial software
• VieVS is in principle working on GNU Octave, but without GUI and it is much slower
– Interpreted language Slower than compiled languages (C++, etc..) • Not a major problem
Why MATLAB?
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Availability and user policy
• VieVS is freely available to registered users: – Easier to get feedback – Easy to spread information about bugs, new updates, etc.
• For more information, see VieVS homepage http://vievs.geo.tuwien.ac.at
( Get VieVS)
• We are open for cooperation: – Modules etc. can be written at other institutions
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Modules of VieVS
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Vie_SETUP
Vie_INIT
Vie_MOD
Vie_LSM Vie_LSM_scan
Vie_SCHED
Vie_SIM Vie_GLOB
Modules of VieVS
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Vie_SETUP
Vie_INIT
Vie_MOD
Vie_LSM Vie_LSM_scan
Vie_SCHED
Vie_SIM Vie_GLOB
Module structure of VieVS: − Possibility to run different processing steps separately − Clear separation of individual tasks
+ E.g. good to try different parameterizations for one task, without repeating previous processing steps
+ Easy to add extensions (as modules) without influencing the core functions + Intermediate results are saved and preserved
− All modules controlled via a common GUI
Modules of VieVS
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Vie_SETUP
Vie_INIT
Vie_MOD
Vie_LSM Vie_LSM_scan
Vie_SCHED
Vie_SIM Vie_GLOB
- Graphical User Interface for all modules - Allows to define all options and parameters - Plotting tools for data inspection (residuals,
estimates, correlation matrices, etc.)
Modules of VieVS
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Vie_SETUP
Vie_INIT
Vie_MOD
Vie_LSM Vie_LSM_scan
Vie_SCHED
Vie_SIM Vie_GLOB
- Graphical User Interface for all modules - Allows to define all options and parameters - Plotting tools for data inspection (residuals,
estimates, correlation matrices, etc.)
Modules of VieVS
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Vie_SETUP
Vie_INIT
Vie_MOD
Vie_LSM Vie_LSM_scan
Vie_SCHED
The core modules for analyzing a session Vie_INIT - reads in data and parameter files Vie_MOD - calculates the theoretical time delay and builds up the partial derivatives Vie_LSM - estimates the unknown parameters with Least Squares Adjustment Vie_LSM_scan - similar to Vie_LSM but uses a scan-wise update of the design matrix (useful for large sessions)
Vie_SIM Vie_GLOB
Modules of VieVS
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Vie_SETUP
Vie_INIT
Vie_MOD
Vie_LSM Vie_LSM_scan
Vie_SCHED
Scheduling module • Automatic scheduling for VLBI
observations
Simulation tool creating artificial observations • Study network geometries, etc.
Global solution • Stacking of single session • Estimate common parameters
Vie_SIM Vie_GLOB
Further information
• VieVS Wiki (http://vievs.geo.tuwien.ac.at) – Complete user manual and documentation – Exercises for beginners – Fundamentals of geodetic VLBI – Etc.
• VieVS user workshops – Held annually since 2010 at Technische Universität Wien, Vienna, Austria – Lectures and practical exercises to learn data analysis with VieVS – Workshop material available on our VieVS Wiki Great information resource!
• Research projects related to VLBI/VieVS at the GEO department, TU Wien – http://vlbi.geo.tuwien.ac.at/
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Thank you for your attention!
Contact: [email protected] [email protected]
