Gauss-Helmert Model for Total Station Positioning Directly in Geocentric Reference Frame Including GNSS Reference Points and Vertical Direction from Earth Gravity Model

摘要

The Gauss-Helmert observational model is derived in this paper for total station positioning directly in geocentric reference frame including Global Navigation Satellite Systems (GNSS) measurements and the vertical direction from the global Earth gravity model. In the simplest case, this positioning method requires GNSS measurements of only two points: the position of the total station and one horizontal angle for the orientation of the total station. The plumb line deflection is taken from the global Earth gravity model to properly account for the difference between the normal direction to the global reference ellipsoid and the direction of the local gravity vector. This method of positioning can be used for generating precise three-dimensional models of objects directly in the geocentric reference frame as well as for the determination of the control points' positions on the objects for laser scanning or terrestrial, drone, and aerial photogrammetry, where the highest accuracy and proper positioning in the geocentric reference frame are required. It can also be used for determination of the geocentric position of the total station, laser scanner, or photogrammetric camera located inside buildings.