Introduction and testing of a cost-effective GNSS system for landslide monitoring

The use of Global Navigation Satellite System (GNSS) in combination with real-time kinematic technique, known as differential GNSS (dGNSS), has increased in recent years for monitoring landslide displacements and detecting early signs of potential failure, enabling an earlier response for risk mitigation than traditional monitoring techniques. GNSS offers several advantages, including high accuracy and high-frequency data collection. Although more cost-effective, their affordability may still present challenges for public organizations managing multiple landslides in their territory. The SparkFun is a suite of components for GNSS assembly designed for topographic surveying, that integrates u-blox ZED-F9P or ZED-F9R modules. The system offers the benefits of dGNSS technology while being more affordable than other market options. It also avoids relying on phone signals for data storage on a cloud server. This paper presents the SparkFun system, its components, and how it can be assembled to create a dGNSS system for landslide monitoring. The deployment and testing at the Chin Coulee landslide in Alberta are discussed. Over the 6-month testing period, the system achieved millimeter accuracy (up to 14 mm), aligning with the manufacturer's specifications. Estimated system errors were found to be comparable to a commercially available dGNSS system (Ophelia Geocube). Additionally, the system exhibits displacement trends similar to the 2018 Geocube monitoring campaign; however, for future deployments, the robustness of the power supply system and the insulation of the equipment need to be enhanced. Overall, the SparkFun system appears to be a promising and cost-effective alternative for monitoring landslide displacements.