Real-Time Deformation Monitoring with Clustered GNSS RTK Networks: An Advanced CORS Approach for Structural Stability Analysis

Deformation monitoring is crucial for structural health monitoring and early warning of natural hazards such as landslides and tsunamis. Given the requisite accuracy at the millimiter or centimeter level, networks of Global Navigation Satellite System (GNSS) receivers with static surveying have been widely adopted for deformation monitoring. However, the primary limitation of static networks is that they typically require post-processing and involve complex adjustment procedures. This study introduces a solution employing a clustered GNSS RTK network that utilizes continuous operating reference stations (CORSs) to offer an alternative strategy for real-time deformation monitoring. In this approach, virtual reference stations are generated and combined with physical monitoring stations to form triangulations, thereby enabling redundancy for cluster adjustment even when fewer than three physical GNSS receivers are used. Data processing is conducted using the Extended Kalman Filter (EKF) and cluster adjustment techniques. Two experiments were conducted to evaluate the performance under different testing conditions and data processing strategies. The results indicate that the cluster adjustment enables the output solution at a 1 Hz frequency, with significantly improved performance compared to traditional GNSS RTK and EKF methods.