| Abstrakt: |
Abstract: Accurate heights are needed in engineering and geodynamics. The classical technique of height determination is spirit leveling. In recent years GNSS - leveling offers an efficient alternative. The paper deals with the combination of existing leveling networks. In many cases, in a specified area more than one leveling network exist, realized at different epochs and based on different techniques and instrumentation. Hence, the surveyor should have the capability to exploit all the existing height information in order to establish an optimal network, i.e. the most accurate one. We describe a methodology for the optimal combination of vertical networks when these share some common benchmarks. Its advantage is the fact that all the existing height information can eventually be transferred to a new vertical network that is more accurate than the individual networks. The approach is tested on three co - located leveling networks (one trigonometric network, two spirit leveling ones) in a regional area located in Greece. The results reveal a significant improvement of 5 mm of the standard deviations of the height estimates compared to the prior situation. |
