Possibilities of using GNSS in an underground mine – satellite positioning pilot at a depth of 400 m

Global navigation satellite systems (GNSS)-based safety, efficiency and management systems are widely used in extractive operations worldwide. While on the surface, in open-pit mining operations, no additional technology is required for the location-based services (LBS). However, in underground conditions, it becomes more challenging to provide navigation services. Various technologies and methods have been proposed and tested to provide LBS in indoor and underground spaces. The main motivation behind expanding GNSS into underground conditions is the robust, already existing, system infrastructure and simple, functional integration with globally available off-the-shelf receivers. The piloted GNSS simulation system is tested in a mine tunnel section 400 m underground in the Pyhäsalmi Mine located in Pyhäjärvi, Finland. A 200 m long tunnel is equipped with 17 GPS signal emulators. The resulting satellite signal coverage is tested with multiple common handheld GNSS receivers. Using the gathered positioning data, the emulated signal accuracy is spatially and statistically analysed. The results of this study will give an indication of how reliably GNSS emulation techniques can be adopted in deep underground use cases and what the main development areas for the technology are.