Quality Control of Height Benchmarks in Attica, Greece, Combining GOCE/GRACE Satellite Data, Global Geopotential Models and Detailed Terrain Information

摘要

The incorporation of the newly available satellite data of GOCE and GRACE missions into global geopotential model solutions provides valuable information on the low to medium frequency band of the gravity field spectrum, an important connection to height datum control and unification. The use of this enriched contribution to existing national height systems quality control will reveal the well known inconsistencies in previous vertical network establishment methods, as well as strengthen the connection solution between adjacent national networks. The quality control of the vertical network in Attica region (Central Greece) is evaluated in the present study. Collocated GPS/levelling and gravity observation points are utilized with emphasis to trigonometric benchmarks and height reference sites. A spectral enhanced combination scheme is used for the network quality investigation based on the frequency content of pure satellite solutions (GOCE and GRACE) and combined satellite and ground global geopotential model solutions of high degree of expansion. Detailed DTM (Digital Terrain Model) information is incorporated in order to estimate Residual Terrain Model (RTM) effects, leading to an expansion degree of 648,000 (1 arcsec). Finally, detailed information about the quality of the height network in Attica is presented in conjunction to proposals towards the establishment of a new height network.