Analysis of the Impact of Rotating GNSS Antennae in Kinematic Terrestrial Applications

Jens-André PAFFENHOLZ，Tobias KERSTEN，Steffen SCHÖN，Hansjörg KUTTERER
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Overview – For direct geo-referencing of static terrestrial laser scans a method developed at the Geodetic Institute of the Leibniz Universitaet Hannover utilises an eccentrically mounted GNSS antenna on top of the laser scanner. The at least 360 degree rotation about its vertical axis is suitable for deriving the position as well as the azimuthal orientation of the sensor. In this approach the alternating antenna orientation with respect to an Earth-Centred, Earth-Fixed reference system will contribute to the error budget due to the right-hand circular polarisation of the satellite signals and the phase centre corrections (offsets and associated variations). For local precise applications the error magnitude has to be considered.
　　This paper focus on the assessment of systematic effects of an eccentrically rotating GNSS antenna. A simultaneous acquired tacheometer trajectory and a computed theoretic trajectory are used for verification. For the determination of the tacheometer trajectory a (360 degree) prism is directly attached below the GNSS antenna. The theoretic trajectory is computed based on the known geometry of the GNSS antenna mount on top of the laser scanner. A first data analysis with respect to systematic effects is carried out in the observation domain. A second data analysis is performed in the coordinate domain, which is of major interest because of the position and orientation estimation from coordinates. Hence, the analysis focuses on the impact of systematic errors in the coordinate domain. The results are evaluated with respect to their significance for the previously introduced application: the direct georeferencing of static laser scans.