At present, GNSS monitoring of landslides is an accepted and approved method to detect movements of slopes at risk in the sub-centimeter level. However, high-precision geodetic GNSS-receivers are expensive, therefore this monitoring method is not widely applied. During the project GeoWSN, a cost effective and yet precise monitoring system was developed at Graz University of Technology by a project consortium under the lead of the Institute of Navigation. The system is based on a Wireless Sensor Network (WSN), featuring low-cost GNSS-receivers and a communication link between the individual sensor nodes to transfer data in real-time to apply RTK. To ensure an evaluation and interpretation of the movement, the data is accessible to a local warning centre.