Investigating the gravitational stability of a radio telescope’s reference point using a terrestrial laser scanner: Case study at the Onsala Space Observatory 20-m radio telescope
Artikel i vetenskaplig tidskrift, 2019

In geodetic very long baseline interferometry, pairs of radio telescopes simultaneously observe signals from quasi stellar objects to estimate the baseline between their reference points. Gravity-dependent variations of the radio telescopes’ reference points deteriorate the estimated baseline's accuracy since they lead to signal path variations in the radio telescopes. This study investigates a new concept for determining the stability of a radio telescope's reference point. Differing to previously used strategies, this concept is able to reveal instabilities due to an elevation-dependent tumbling of the telescope independent from the part of the axis offset that is constant for all elevation angles. The new concept is exclusively based on terrestrial laser scanning that at the same time is used for analyzing the main reflector's shape deformation. We applied this concept to the Onsala Space Observatory (OSO) 20-m radio telescope: The results show that we cannot disprove the reference point's stability. In general, our new strategy can be transferred to also investigate the stability of other radio telescopes’ reference points. A prerequisite for this strategy is that the laser scanner – that moves between the elevation angles – observes identical objects from different stations. These objects need to be stable during all measurements. In the case of the OSO 20-m radio telescope, the radome is used for this purpose.


Bundle adjustment

Parameter estimation

Deformation analysis

Laser scan registration


Christoph Holst

Universität Bonn

Axel Nothnagel

Universität Bonn

Rüdiger Haas

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

Heiner Kuhlmann

Universität Bonn

ISPRS Journal of Photogrammetry and Remote Sensing

0924-2716 (ISSN)

Vol. 149 67-76

Onsala rymdobservatorium infrastruktur

Vetenskapsrådet (VR) (2017-00648), 2018-01-01 -- 2021-12-31.


Hållbar utveckling


Annan teknik

Geovetenskap och miljövetenskap


Grundläggande vetenskaper


Onsala rymdobservatorium



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