Measuring Focal Length Variations of VGOS Telescopes Using Unmanned Aerial Systems
Paper i proceeding, 2019

VLBI radio telescopes are large technical facilities whose structures are aected by several deformation patterns. In particular, temperature- and gravity-dependent deformations bias the estimated global telescope position and, therefore, if uncorrected, deteriorate the geodetic results that can be derived from the geodetic VLBI analysis. The rigidity of a telescope structure under varying acting forces is restricted by its structural properties. Large conventional radio telescopes are more affected by deformation effects than the new compact-designed VGOS antennas. The design document for the next generation VLBI system (today called VGOS) states <300 µm as requirement for the path length stability. A traceable metrological system that can be used to check this stability level must be at least three times better than the requirements. Close range photogrammetric methods fulfil these accuracy requirements but usually need a crane during the survey of a telescope. To avoid the latter, an unmanned aerial system was used for the first time to evaluate the possible deformation of the main reflector surface of the north-eastern of the Onsala twin telescopes (ONSA13NE). The focal length of the ring-focus paraboloid was derived in several elevation angles to study the gravitational deformation effects on the main reflector of this VGOS antenna.

Antenna deformation

VGOS

Focal length

Unmanned aircraft system

Ring-focus paraboloid

Författare

Michael Lösler

Högskolan i Frankfurt

Cornelia Eschelbach

Högskolan i Frankfurt

Rüdiger Haas

Chalmers, Rymd-, geo- och miljövetenskap, Onsala rymdobservatorium, Rymdgeodesi och geodynamik

Ansgar Greiwe

Högskolan i Bochum

Proceedings of the 24th European VLBI Group for Geodesy and Astrometry Working Meeting

17-21

24th European VLBI Group for Geodesy and Astrometry Working Meeting
Las Palmas, Spain,

Drivkrafter

Hållbar utveckling

Fundament

Grundläggande vetenskaper

Infrastruktur

Onsala rymdobservatorium

Ämneskategorier

Geovetenskap och miljövetenskap

DOI

10.7419/162.08.2019

Mer information

Senast uppdaterat

2019-12-22