Multimodal sensor system for high-precision monitoring of structural geological movements

Abstract

Abstract This paper presents a multimodal sensor system for high-precision monitoring of structural geological movements based on the integration of Real-Time Kinematic Global Navigation Satellite System (RTK-GNSS) and a MEMS-based inclinometer. This combination enables not only the monitoring of overall surface displacements but also the detection of displacement gradients and movements occurring in subsurface layers, providing a comprehensive characterization of structural geological movements. The system employs a base station and rover architecture, where GNSS correction data are transmitted via a 868MHz radio link to achieve centimeter-level positioning accuracy. In addition, the inclinometer is designed to detect tilt variations below 0.3∘, which correspond to displacement changes in the centimeter range depending on the effective lever arm of the installation. Measurement data are processed by a microcontroller (μC), transmitted to a central gateway using LoRa communication and eventually stored on a data server. To improve longterm stability, temperature-induced angle offsets were determined from temperature chamber measurements and corrected using fourth-degree polynomial compensation models. Field deployment on a structurally active hillside enables the verification of the developed system under real-world environmental conditions. The RTK-GNSS measurements and inclinometer data provide stable results during observation. They demonstrate that the proposed system is capable of detecting small-scale structural movements and represents a cost-effective and promising solution for continuous structural health monitoring applications.