Hybrid-Precision GNSS Positioning Strategies for Landslide Monitoring

Global Navigation Satellite System (GNSS) is now widely applied for early warning of natural hazards such as landslides. Given the required accuracy at the millimeter or centimeter level, networks of 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. In contrast, GNSS RTK enables to provide near real-time solution but has limitation in accuracy. To overcome these limitations, a hybrid GNSS positioning strategy have been proposed. In this approach, multi-function GNSS receivers are used and setup to implement both the GNSS RTK function and output raw data for accurate post processing. While GNSS RTK can provide displacement parameters at the centimeter level at frequency of 1Hz for early warning of natural hazards in the case of seriously landslide, post-processing, with network adjustment, provides accurate positioning solution in frequency of some hour for long term monitoring and reliable assessment of risk. Advanced data streaming, management and processing are also introduced in this study. The result from experiment and on-site project demonstrated the advantages of the hybrid strategy, which allowing for both real-time warning in the case of emergency landslide and accurate long-term risk deformation monitoring.