Landslides and slope instabilities triggered by intense rainfall events are a growing concern worldwide. Climate change is expected to increase the frequency of extreme precipitation, raising the risk to communities and critical infrastructure. In high-risk areas, automated monitoring systems are essential to detect early signs of movement and allow timely intervention.
Monitoring three-dimensional ground movements remains a complex technical challenge. While a range of technologies exists —from robotic total stations, terrestrial or satellite radars, cameras, GNSS receivers, or indirect systems based on inclinometers— each comes with technical or cost limitations, especially when installed permanently for automated data collection. As a result, many projects still rely on periodic topographic measurement campaigns at control points. These methods can be effective, but because they depend on the timing of field visits, the resulting data is often temporally sparse, making it harder to detect rapid changes or subtle movement trends in real time.
Worldsensing’s GNSS Meter, which combines RTK positioning with LoRa communication for differential corrections, offers a competitive alternative—delivering sub-centimeter accuracy, high data availability, and reduced operational costs.
The comparative study
Worldsensing, in collaboration with the Institut Cartogràfic i Geològic de Catalunya (ICGC) and researchers from the Universitat Politècnica de Catalunya and the Universitat Oberta de Catalunya, conducted a head-to-head performance comparison between three GNSS Meters and a permanently installed RTS, both tracking the same observation pillars in an active subsidence zone.
The installation parameters are summarised in the following table:
| Category | RTS (Robotic Total Station) | GNSS Meter |
| Equipment | Trimble S9 0.5″ Robotic Total Station | Worldsensing GNSS Meter |
| Measurement Frequency | Every 6 hours (27 min per cycle) | Every hour |
| Data Transmission | Cellular connection | LoRa – single, 6h, and 24h aggregates |
| Power & Connectivity Needs | Requires mains power and internet | Battery-powered, no permanent internet needed |
| Distance to Monitoring Points | PMN-1: 113 mPSN-1: 78.5 mPSN-2: 91 m | PMN-1: 225 mPSN-1: 151 mPSN-2: 172 m |
| Observation Period | 100–132 days (matching GNSS) | 100–132 days (matching RTS) |
Results: matched accuracy from GNSS Meter with RTS
After the observation period, the study showed that GNSS Meters with 24-hour aggregation matched the RTS in accuracy for horizontal and vertical measured displacements.
The study also compares the velocities estimated using a linear approximation, also incorporating metrics that allow the reliability and consistency of the two measurement systems being compared to be evaluated.
Key findings:
- RTS data contained more outliers, especially during rainy periods. This is expected, as it applies no aggregation to reduce short-term noise.
- GNSS data showed no anomalies when using 24-hour aggregation, as temporal averaging reduced the impact of occasional measurement errors.
- Vertical GNSS readings had slightly greater dispersion than horizontal readings—an expected GNSS characteristic—but still within sub-centimeter range.
Better performance in adverse weather for the GNSS Meter
Heavy rainfall reduced RTS data quality, increasing dispersion and even preventing complete daily readings. On the other hand, GNSS Meters maintained consistent precision and reporting rates regardless of weather, demonstrating greater environmental resilience.
Data availability
Data availability is critical for reliable monitoring, and GNSS Meters outperformed RTS in the study:
- Higher acquisition success rate than RTS over the observation period.
- RTS missed full days of measurements and partial days with only 25% coverage
- GNSS maintained steady reporting, with a further boost in performance after a configuration change increased device warm-up time
Why GNSS Meters are competitive
While RTS remains a trusted tool for precise, discrete measurements, GNSS Meters offer significant advantages for continuous, autonomous monitoring:
- Continuous data with hourly sampling and flexible aggregation windows
- Sub-centimeter precision when using 24-hour aggregates
- Higher reliability in all weather conditions
- Lower total cost of ownership, making high-quality monitoring accessible to more projects
Conclusion
The case study confirms that Worldsensing’s GNSS Meter is a robust, precise, and cost-effective solution for long-term ground movement monitoring. With RTK positioning, LoRa connectivity, and battery autonomy of up to two years, it overcomes the limitations of traditional RTS systems.