Advanced Navigation, a global leader in navigation and autonomous systems, successfully demonstrated a breakthrough in underground navigation at Europe's deepest mine in Pyhäjärvi, Finland. They delivered high-precision positioning without relying on fixed infrastructure or GNSS.
The company’s hybrid navigation system, which combines a laser velocity sensor (LVS) with the Boreas D90 fiber-optic gyroscope (FOG) inertial navigation system (INS), maintained a consistent navigation error below 0.1% across multiple runs. It achieved this performance without depending on any fixed positioning infrastructure, pre-existing maps, or external aiding.
Joe Vandecar, senior product manager at Advanced Navigation, said: “Unreliable navigation underground isn’t a minor technical constraint - it’s a major operational bottleneck. Maintaining precision over a 22.9km subterranean course in Europe’s deepest underground mine demonstrates a level of performance that few systems in the world can rival without any prior intelligence of the environment. These results prove we’re one step closer to unlocking scalable underground autonomy.”
Positioning challenges in underground navigation
Navigating the vast subterranean network of the Pyhäsalmi Mine presents significant challenges. Located 1.4 km underground at a 63-degree latitude—just two degrees below the Arctic Circle—traditional systems fail here, and the mine is completely impervious to GNSS signals. Its repetitive, multi-level tunnel network increases the risk of visual disorientation, while metallic ores distort magnetic fields and scatter radio waves.
To address these conditions, mines typically depend on infrastructure-heavy solutions such as ultra-wideband beacons, Wi-Fi, 5G repeaters, or perception-based techniques like SLAM (Simultaneous Localization and Mapping), which require cameras. These methods are costly to deploy and maintain, slow to install, and often unavailable in hazardous or unmapped zones where reliable navigation is most crucial. Moving to a truly resilient navigation system with less dependency on infrastructure offers a scalable alternative, enabling reliable navigation even in the most inaccessible or hazardous environments.
Precision with less infrastructure: An inertial-centered architecture
Championing this architecture, the hybrid navigation system is centered on Boreas – a world-class FOG INS. Unlike conventional systems, Boreas doesn’t rely on GNSS or magnetic compasses. Instead, it uses ultra-sensitive FOG technology to detect the Earth’s rotation and determine true North, a process known as gyrocompassing to find the vehicle's direction (heading).
To maintain and enhance this accuracy, the INS is fused with Advanced Navigation’s LVS. Using infrared lasers, LVS continuously measures the vehicle's true 3D velocity relative to the ground. This real-time data is critical for correcting the gradual ‘drift’ that occurs in standalone inertial systems, enabling the hybrid system to maintain precision over extended distances.
This integration is made possible with Advanced Navigation’s AdNav OS Fusion software. Using adaptive algorithms, it dynamically weighs the reliability of each sensor in real time. Together, these technologies form a resilient hybrid system delivering precise, uninterrupted navigational data in extreme environments, without GNSS or fixed infrastructure.
Magnus Zetterberg, senior consultant at Combitech, who observed the demonstration, shared: “We were thoroughly impressed by the results the sensor fusion provided. I have used and been exposed to these sorts of sensors in other projects, and nothing has come close to this level of performance. It’s clear the Laser Velocity Sensor is a major key in providing these outstanding results.”
Proven in the 3D depths of Europe’s deepest mine
Selected from over 90 global applicants, a demonstration of the hybrid navigation system was livestreamed from the Pyhäsalmi Mine in Pyhäjärvi, Finland, as part of the Deep Mining Open Call under BHP’s think and act differently (TAD) program.
Validated across five separate runs in complete isolation from external aids or maps, the hybrid navigation system repeatedly achieved an accuracy of better than 0.1% of distance traveled. This performance demolishes a barrier once considered fundamental to underground navigation.
Runs 1, 2 and 3: Accuracy surpassing surface-level GNSS
Over a 6 km rough and rugged terrain that extended 400 m below the surface, the system achieved a best-case 3D position error of just 0.55 m (0.009%), with an average error of 2.83 m (0.047%). For context, standard single-band GNSS on the surface typically delivers 2–10 m accuracy in open-sky conditions. This system delivered significantly greater precision even within a subterranean labyrinth.
Olli Mylläri, vice president of technology at Normet, stated: “We’ve worked in underground environments for decades. Seeing this level of precision achieved on the first run signals huge potential for safer and more efficient underground vehicle operations.”
Run 4: Maintaining precision over a half-marathon underground
The system navigated a 22.9 km route to a depth of 1,400 m - the equivalent of a half-marathon in total darkness. The final position error was 15.9 m (0.07%), showcasing its immunity to the drift that plagues other inertial systems.
Run 5: True "anywhere, anytime" navigation
The graph below illustrates the ultimate test of self-reliance - a true north-seeking initialization conducted 1.4 km underground. Without relying on magnetometers or external aids, the system determined direction (heading) using its built-in gyrocompassing procedure, measuring the Earth’s rotation to establish true north. It then navigated a 1 km course with just meter of error, demonstrating its capability for rapid deployment in the most challenging and unfamiliar terrain.
A full report has been published here for an in-depth look into the results achieved.
Unlocking scalable autonomy in mining
While mines will continue to use fixed infrastructure, this technology significantly reduces dependency, enabling resilient, high-precision navigation in previously inaccessible or unmapped areas. This performance marks a step change in underground navigation, unlocking new potential for fleet management, predictive collision avoidance, material tracking and scalable autonomy across mining operations.
Olli Mylläri, vice president of technology at Normet, said: “At Normet, we specialize in advanced solutions for underground mining and tunnelling, so we know firsthand how difficult accurate and reliable navigation can be in these environments. Seeing Advanced Navigation’s Hybrid Navigation System deliver consistent positioning with minimal infrastructure deep within the Pyhäsalmi Mine was remarkable. It’s a powerful step forward for automation and safety in the underground space.”
In today’s dynamic operational environments, relying on a single navigation technology is no longer viable. Robust navigation demands a layered, inertial-first and multi-sensor architecture – held together by intelligent software – that can adapt and scale to meet the unique demands of each operation.
Joe Vandecar, senior product manager at Advanced Navigation, added:“Ultimately, this vehicle-based, inertial-centered architecture provides the resilient foundation required for the mining sector to achieve its long-term goal: efficient autonomous ore extraction at depths hostile to human activity.”
The hybrid navigation system is set for commercial release in late 2025.
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