Vienna VLBI and Satellite Software (VieVS) for Geodesy and Astrometry

Johannes Böhm,Janina Boisits,Lucia Mccallum,Sigrid Böhm,Kamil Teke,Matthias Schartner,David Mayer,Jamie Mccallum,Daniel Landskron,Anastasiia Girdiuk,Hana Krásná,Jakob Gruber,Andreas Hellerschmied,Matthias Madzak

doi:10.1088/1538-3873/aaa22b

Abstract

The Vienna VLBI and Satellite Software (VieVS) is state-of-the-art Very Long Baseline Interferometry (VLBI) analysis software for geodesy and astrometry. VieVS has been developed at Technische Universität Wien (TU Wien) since 2008, where it is used for research purposes and for teaching space geodetic techniques. In the past decade, it has been successfully applied on Very Long Baseline Interferometry (VLBI) observations for the determination of celestial and terrestrial reference frames as well as for the estimation of celestial pole offsets, universal Time (UT1-UTC), and polar motion based on least-squares adjustment. Furthermore, VieVS is equipped with tools for scheduling and simulating VLBI observations to extragalactic radio sources as well as to satellites and spacecraft, features which proved to be very useful for a variety of applications. VieVS is now available as version 3.0 and we do provide the software to all interested persons and institutions. A wiki with more information about VieVS is available at http://vievswiki.geo.tuwien.ac.at/.

Highlights

In geodetic and astrometric Very Long Baseline Interferometry (VLBI), several software packages are available
The International VLBI Service for Geodesy and Astrometry (IVS) has organized two comparison campaigns (Plank et al 2010; Klopotek et al 2016) that found that the theoretical delays computed with the software packages and used in the parameter estimation process agree at the one millimeter level or better for most of the software packages including Vienna VLBI and Satellite Software (VieVS)
With the current 3.0 version of VieVS, we start the analysis of VLBI observations with group delays at X-band as provided with the so-called NGS cards or the equivalent vgosDB files, which means that group delay ambiguities and ionosphere delays have been removed before (Schuh & Böhm 2013; Sovers et al 1998)

Summary

Introduction

In geodetic and astrometric Very Long Baseline Interferometry (VLBI), several software packages are available. Before developing VieVS, we used Occam for the analysis of VLBI observations. As Occam is written in Fortran and without a graphical user interface, it was rather difficult to get students involved in the development of VLBI software.

VLBI for Geodesy and Astrometry

Scheduling and Simulation

Parameter Estimation

VLBI Observations to Satellites

Plans for VieVS and Outlook

Summary