Ray tracing-based delay model for compensating gravitational deformations of VLBI radio telescopes

Abstract: The precision and the reliability of very long baseline interferometry (VLBI) depend on several factors. Apart from fabrication discrepancies or meteorological effects, gravity-induced deformations of the receiving unit of VLBI radio telescopes are identified as a crucial error source biasing VLBI products and obtained results such as the scale of a realized global geodetic reference frame. Gravity-induced deformations are systematical errors and yield signal path variations (SPVs). In 1988, Clark and Thomsen derived a VLBI delay model, which was adopted by the International VLBI Service for Geodesy and Astrometry (IVS) to reduce these systematic errors. However, the model parametrizes the SPV by a linear substitute function and considers only deformations acting rotationally symmetrically. The aim of this investigation is to derive the signal path variations of a legacy radio telescope and a modern broadband VGOS-specified radio telescope and to study the effect of nonrotationally symmetric deformation patterns. For that purpose, SPVs are obtained from a nonlinear spatial ray tracing approach. For the first time, a tilt and a displacement of the subreflector perpendicular to the optical axis of the feed unit is taken into account. The results prove the commonly used VLBI delay model as a suitable first-order delay model to reduce gravity-induced deformations.

Object Details

• Location: Deutsche Nationalbibliothek Frankfurt am Main
• Extent: Online-Ressource
• Language: Englisch

References and Relationships

• Bibliographic citation: Ray tracing-based delay model for compensating gravitational deformations of VLBI radio telescopes ; volume:12 ; number:1 ; year:2022 ; pages:165-184 ; extent:20 ; Journal of Geodetic Science ; 12, Heft 1 (2022), 165-184 (gesamt 20)

Contributors, Places and Time

• Creator: Lösler, Michael ; Eschelbach, Cornelia ; Greiwe, Ansgar ; Brechtken, Rainer ; Plötz, Christian ; Kronschnabl, Gerhard ; Neidhardt, Alexander

Further information

• DOI: 10.1515/jogs-2022-0141
• URN: urn:nbn:de:101:1-2022112213022504760658
• Rights: Open Access; Der Zugriff auf das Objekt ist unbeschränkt möglich.
• Last update: 15.08.2025, 7:24 AM CEST