Authors: Cornelia Eschelbach, Benedikt Soja, Rüdiger Haas, Michael Lösler Inspecting geodetic measuring instruments to ensure their performance, accuracy, and traceability is an inherent part of surveying. In addition to mobile terrestrial instruments such as levelling instruments, total stations, and GNSS receivers, inspections of the geodetic infrastructure used to define, establish, and maintain global geodetic reference frames become more important due to increasing accuracy requirements. Radio telescopes used for very long baseline interferometry (VLBI) exhibit orientation-dependent deformation behaviour due to their dimension and weight, which causes systematic deviations in VLBI observations. The currently applied correction model is incomplete and accounts for only parts of the deformations that actually occur, as recent studies show. Depending on the telescope, these non-representative corrections can even lead to a systematic bias in VLBI observations. This contribution presents the comprehensive analysis developed by the IAG/IERS Working Group on Metrology of Space Geodetic Infrastructure in close cooperation with the International VLBI Service for Geodesy and Astrometry, which allows for the consideration of all occurring and modellable deformations.