TY - JOUR
T1 - Investigating the gravitational stability of a radio telescope's reference point using a terrestrial laser scanner
T2 - Case study at the Onsala Space Observatory 20-m radio telescope
AU - Holst, Christoph
AU - Nothnagel, Axel
AU - Haas, Rüdiger
AU - Kuhlmann, Heiner
N1 - Publisher Copyright:
© 2019
PY - 2019/3
Y1 - 2019/3
N2 - 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.
AB - 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.
KW - Bundle adjustment
KW - Deformation analysis
KW - Laser scan registration
KW - Parameter estimation
KW - VLBI
UR - http://www.scopus.com/inward/record.url?scp=85060332386&partnerID=8YFLogxK
U2 - 10.1016/j.isprsjprs.2019.01.010
DO - 10.1016/j.isprsjprs.2019.01.010
M3 - Article
AN - SCOPUS:85060332386
SN - 0924-2716
VL - 149
SP - 67
EP - 76
JO - ISPRS Journal of Photogrammetry and Remote Sensing
JF - ISPRS Journal of Photogrammetry and Remote Sensing
ER -