The 2008 local-tie determination at the Onsala Space Observatory

M. Lösler1, and R. Haas2

1Geodetic Institute, University Karlsruhe (TH), Germany
2Department of Radio and Space Science, Chalmers University of Technology, Sweden

Oral presentation

We present the results of the local-tie determination performed at the Onsala Space Observatory in the fall of 2008. For this project a laser tracker Leica LTD840 and corresponding targets in form of corner-cube reflectors and cat-eye reflectors were used. The instrument was applied in an unusual and innovative way to adopt to the local environment. Measurements inside the telescope radome were done to determine the intersection of the telescope azimuth and elevation axis. Additionally, a traverse was measured using the laser tracker in order to determine the local-tie between the reference points of the radio telescope and the GNSS-monument at Onsala. The data were analyzed in a one-step approach and the complete covariance matrix of the results was determined. The coordinates of the reference points and the local-tie were derived in the local cartesian system with accuracies in the sub-mm range. A comparison to the results of a previous local-tie determination performed in 2002 shows good agreement and stability at the sub-mm level. We also determined and confirmed the  telescope axis offset.