Landslide monitoring using permanent low-cost GNSS sensors and InSAR techniques

The Dunaszekcso landslide is one of the major landslides in Hungary located at the right bank of the Danube in the southern part of the country. The landslide shows a retreat of 5-15m per 100 year in the past 2000 years according to geological studies. In this area, the high riverbanks recently experienced major slides, which damaged houses and linear structures. The area has been being monitored for several years using InSAR technique and static GNSS observations, but due to the low temporal resolution of the static GNSS observation campaigns and the lack of frequent absolute displacement control, the InSAR data processing sometimes face significant challenges.

To overcome this problem, we teemed up with European universities, geological services and companies in the GeoNetSee (GeoNetSee – ‘An AI/IoT-based system of GEOsensor NETworks for real-time monitoring of unStablE tErrain and artificial structures’) project (Interreg Danube Region programme, no: DRP0200783), which focuses on developing and testing innovative geodetic approaches for monitoring slope instabilities and infrastructure-related geohazards. Within the GeoNetSee framework, low-cost GNSS receivers are installed at selected slopes, and time series from variometric processing are analysed to identify subtle dynamic and quasi-static displacements caused by environmental loading, rainfall-induced pore pressure changes, and other disturbances. GNSS-derived signals are validated against complementary monitoring methods, including InSAR, traditional geodetic surveys and environmental sensors.

The primary objective of this study is to assess the potential of various GNSS-based observation processing strategies (RTK, fast static, variometric) to detect early deformation signals that may precede landslide events. Low-cost permanent and monitoring GNSS stations were placed on the steep slopes and on the stable ground to monitor the geometrical changes of the slopes and the GNSS observations are analysed with different measurement models and compared to the results of InSAR analysis.

Preliminary results demonstrate that low-cost GNSS techniques are valuable means to detect small-amplitude, short-term slope deformations, indicating changes in stability conditions. These findings highlight the method’s potential as part of integrated slope monitoring and early-warning systems, offering continuous, autonomous, and real-time data that can enhance landslide risk assessment and mitigation strategies in climate-sensitive regions of Central Europe and beyond.