Pipeline & Underground
High-precision positioning for kilometer-scale GNSS-denied pipeline runs, tunnel surveys, horizontal directional drilling, and subsurface infrastructure mapping.
Talk to an Expert →Why AlgoNav for Underground
Reliable positioning through underground stretches where GNSS is unavailable for hundreds of meters or several kilometers, combining surface control points, inertial navigation, and drift-constrained post-processing.
Tunnel Mapping
Continuous 3D trajectory estimation through tunnels with tightly-coupled inertial processing. AlgoNav georeferences tunnel point clouds from vehicle- or drone-mounted laser scanners and maintains alignment across long GNSS outages.
Pipeline Inspection
Precise georeferencing for in-line inspection (ILI) and PIG runs. AlgoNav fuses launch/receive GNSS fixes with onboard IMU and optional odometer data so each detected anomaly is tied to an absolute coordinate for excavation planning.
Reference Point Alignment
Underground runs start with rigorous alignment to the surface frame. AlgoNav performs coordinate transfer at launch, supports surveyed tunnel reference points and shaft fixes, and preserves a consistent frame over the full trajectory.
HDD Bore Navigation
Positioning for horizontal directional drilling in vibration-heavy conditions. AlgoNav processes drill-head inertial data with intermittent surface control to reconstruct the drilled bore path and validate as-built alignment against design.
Applications
Specialized positioning workflows for tunnel, pipeline, and HDD operations where GNSS is denied for extended distances.
Pipeline Inspection Gauge (PIG) Positioning
In-line inspection tools travel through pipelines collecting wall-thickness, geometry, and corrosion data over long GNSS-denied segments. AlgoNav georeferences these observations by combining launch and receive GNSS control with PIG IMU data and optional wheel/odometer increments. Forward-backward smoothing and error-state modeling bound inertial drift so every anomaly receives a defensible coordinate for field excavation.
Tunnel Survey and As-Built Documentation
During and after tunnel construction, precise knowledge of the actual tunnel trajectory is essential for quality control and regulatory compliance. AlgoNav computes a continuous 3D trajectory using IMU data from survey vehicles or drones and georeferences laser-scanner point clouds to the project datum. Entry/exit GNSS control plus occasional surveyed tunnel reference points constrain the solution and keep drift within engineering tolerances.
Horizontal Directional Drilling (HDD)
Trenchless pipe installation requires precise guidance and as-built documentation of the drilled bore path. AlgoNav processes drill-head gyroscope and accelerometer data, handles high vibration and curvature, and ties the result to surface control coordinates. This HDD borehole navigation workflow verifies alignment against design and supports regulatory submissions and utility registration.
Extended GNSS-Denied Infrastructure Runs
Mining shafts, sewer networks, and underground utility corridors share the same core problem: no satellite visibility over long distances. AlgoNav provides a common post-processing workflow that integrates IMU, gyrocompass, and odometer data with any available reference points to deliver consistent georeferenced trajectories for GIS and asset management.
Challenges We Solve
Underground environments combine complete GNSS denial, high dynamics, and strict georeferencing requirements.
GNSS-Denied Long Distances
Pipeline and tunnel operations routinely require navigation through hundreds of meters to multiple kilometers with zero satellite visibility. AlgoNav keeps the trajectory connected from entry to exit by tightly coupling inertial propagation with surface control constraints.
Inertial Drift Control
Advanced error-state filtering with forward-backward smoothing minimizes IMU drift during long outages. By solving from both ends and applying absolute constraints, AlgoNav distributes residual error across the full segment instead of letting drift accumulate unbounded from one side.
Reference Points and Alignment
Initial alignment and coordinate transfer are critical before entering the underground segment. AlgoNav anchors the run to a surveyed entry frame, ingests intermediate control points when available, and enforces consistent alignment to the surface coordinate system at exit.
Harsh Dynamics and 3D Geometry
PIG tools and drill heads experience vibration, shock, and tight 3D curvature. AlgoNav fuses IMU, odometer, gyrocompass, and GNSS inputs as available, preserving attitude and trajectory fidelity through sloped, twisting, and non-level paths.
How It Works Underground
From entry alignment and surface control to a drift-bounded, georeferenced trajectory through the full pipeline, tunnel, or HDD bore.
Underground positioning fails if alignment and drift control are treated as separate problems. AlgoNav solves both in one estimation chain: transfer a precise frame at entry, propagate motion continuously with inertial sensors through GNSS-denied stretches, and constrain the solution with exit control and internal reference points when available.
Entry Alignment and Surface Control
High-precision GNSS is measured at launch and receive points, then transferred into the project coordinate frame. These control observations establish initial attitude and position alignment for the underground run and define the absolute constraints for the final solution.
Continuous Inertial Propagation
As the PIG, tunnel platform, or drill head travels underground, IMU, gyro, and optional odometer signals record motion continuously. This provides uninterrupted relative navigation through long GNSS-denied stretches, including curved and sloped 3D segments.
Drift Bounding with Reference Constraints
AlgoNav processes inertial data forward and backward, constraining the solution with entry/exit control and any intermediate tunnel reference points or shaft fixes. The merged estimate bounds drift over kilometer-scale runs and improves internal consistency.
Inspection-Ready Georeferencing
The final output is a continuous, georeferenced 3D trajectory with calibrated uncertainty. PIG anomalies, tunnel point clouds, and HDD as-built measurements are mapped to absolute coordinates for GIS integration, compliance reporting, and targeted field intervention.
Go Underground
Whether you need pipeline inspection positioning, tunnel survey processing, or HDD as-built documentation -- AlgoNav delivers precision where satellites cannot reach.