A Novel All-Weather Method to Determine Deflection of the Vertical by Combining 3D Laser Tracking Free-Fall and Multi-GNSS Baselines

The bright stars in the clear night sky with weak background lights should be observed traditional deflection of vertical (DOV) measurement so that DOV cannot under all-weather conditions, which limits its wide applications. An method combining three-dimensional (3D) laser tracking free-fall and multi-GNSS baselines is proposed this paper. In a vacuum environment, 3D technique used to continuously track observe motion high frequency precision for obtaining coordinate series. plumb line vector equation established solve gravity direction system tracker at measuring point using least squares fitting Multi-GNSS observations are solved precise geodetic cartesian coordinates GNSS baseline information. A transformation based on information paper convert gravitational into system. calculate ellipsoid normal vector, angle between estimated obtain astrogeodetic DOV. projected meridian prime planes components DOV, respectively. astronomical latitude longitude calculated from these two components. simulation experiments were carried out method, it was found theoretical measured by could reach 0.2″, realise observation.