Astronomical-topographic levelling using high-precision astrogeodetic vertical deflections and digital terrain model data

Astrogeodetic Validation of Gravimetric Quasigeoid Models in the German Alps - First Results

In regions with a rough topography, e.g. the European Alps, the accuracy of geoid or quasigeoid models is often reduced. For the validation and accuracy assessment of gravimetric models, astronomical levelling is a well-suited independent method. In a test area, located in the German Alps, a new astrogeodetic data set was acquired using the Hannover Digital Zenith Camera System. Vertical deflec...

Prediction of vertical deflections from high-degree spherical harmonic synthesis and residual terrain model data

This study demonstrates that in mountainous areas the use of residual terrain model (RTM) data significantly improves the accuracy of vertical deflections obtained from high-degree spherical harmonic synthesis. The new Earth gravitational model EGM2008 is used to compute vertical deflections up to a spherical harmonic degree of 2160. RTM data can be constructed as difference between high-resolu...

The Digital Zenith Camera - A New High-Precision and Economic Astrogeodetic Observation System for Real-Time Measurement of Deflections of the Vertical

During the last few years, new developments in the field of geodetic astronomy have been sparsely published. This might be due to the fact that the determination of deflections of the vertical still required relatively large efforts, both in time and in manpower, thus keeping the costs per point at a high level. Recently, the development of new high performance image sensors (CCD) at a reasonab...

Digital Terrain Model Data Structures

This paper describes pertinent digital terrain model data structures, namely, grid/raster, quadtree, and triangular irregular network. A basic concept of DIM data structure is also explained. The aspects of TIN storage, TIN data structure conversion, advantages and disadvantages of each structure are discussed. A complete data structure conversion program is also presented. n. 1.0 INTRODUCTION ...

Assessment of EGM2008 in Europe using accurate astrogeodetic vertical deflections and omission error estimates from SRTM/DTM2006