New Basis Points of Geodetic Stations for Landslide Monitoring

The results of mathematical processing of modern geodetic observations of landslide processes in Dnipropetrovsk on points of observation stations in case of lost basis points are presented. Previous observations were conducted in 1993 using classic geodetic instruments. To provide the required accuracy of observations the local geodetic coordinate system was developed. There were two basis points; using laser range equipment the distance between them was measured with accuracy higher than 0.001 m. New observations were conducted in 2015 using GNSS-technologies and satellite observations in static mode because the traditional methods were impossible to use as the mutual visibility between basis points was lost. The biggest problem in current monitoring was the loss of basis points of monitoring stations. Some suggestions as for choosing the most stable points of network were made. Such points were defined according to previous observations; and the new method of determining the “temporary” basis points by comparing the lengths of lines between points of observation is offered. There were chosen three most stable points with minimal length disparity. Using such method we have transformed satellite observations from WGS-84 to local coordinate system established at the territory of landslide. Such method could be used in case of lost basis points and with considerable number of rather stable observation points. At the same time, we suggest setting the basis points as far from the landslide observation stations as possible. For further observations, we suggest using GNSS-technologies in static mode and setting the new basis points. To improve the accuracy, the observations on basis points will be combined with GNSS and other ground observations.