Worker safety underground,
where GPS doesn't reach.

Across the Grand Paris Express programme, teams work in tunnels, underground stations and restricted technical areas - environments where traditional positioning is simply unavailable. Pole Star delivers continuous worker location without GNSS, directly on the mobile devices field teams already carry.

ClientGrand Paris Express
PartnersKontron - Equans
Use caseWorker safety & location
TechnologyMulti-technology LTE + BLE
Map of the Grand Paris Express metro network under construction Four new metro lines under construction
At a glance

Consistent coverage across every critical area

The project covers underground transport infrastructures where high reliability and resilience are non-negotiable.

4
new metro linesunder construction
No GNSS
undergroundpositioning without satellites
LTE + BLE
multi-technologypositioning combined
Mobile-based
on field devicesteams already carry

Project scope

Field teams equipped with professional mobile devices, operating in underground and restricted environments.

Underground stations Tunnels Restricted technical areas Evolving construction phases
Context & challenges

Safety-critical environments where positioning normally fails

As part of the Grand Paris Express programme, teams operate across four new metro lines under construction. These large-scale transport infrastructures include complex and safety-critical environments - underground stations, tunnels and restricted technical areas - where traditional positioning technologies are unavailable.

The main challenges

Ensure reliable worker location, reinforce worker safety, and support effective alert management.

Limited visibility, confined spaces and the presence of isolated workers require a solution capable of delivering continuous, accurate location data and rapid response capabilities.

No GNSS - satellite positioning simply doesn't reach
Confined spaces - tunnels and restricted technical areas
Isolated workers - lone operators far from their teams
Alert management - response speed depends on knowing where
Underground metro construction environment on the Grand Paris Express programme
Solution deployed

Location built into the devices field teams already use

Pole Star delivers a multi-technology worker location service integrated directly into the professional mobile devices used by field teams - providing continuous location across underground environments, without reliance on GNSS.

1

No new hardware for workers

The service runs on the professional mobile devices field teams already carry - nothing extra to issue or maintain.

2

Positioning without satellites

Multi-technology positioning combining LTE and BLE signals keeps location continuous where GNSS cannot reach.

3

Visibility everywhere it matters

Coverage throughout stations, tunnels and technical zones - the areas where isolated workers are most exposed.

4

Adapts as the site evolves

A mobile-based deployment model that adapts easily to evolving construction phases and operational constraints.

Field worker using a professional mobile device in an underground metro environment

Reliability is the requirement, not a bonus

The solution maintains reliable performance in harsh underground conditions - the environments where a location gap has the highest consequence.

Architecture & solutions

A robust and flexible location architecture

The architecture ensures reliable and scalable location services across complex metro infrastructures.

Architecture · multi-technology positioning underground

NAO® Mobile SDK

For smartphone-based worker location, embedded in the professional devices field teams use.

NAO® BlueSpot V4 Rugged

Designed specifically for underground and industrial environments.

Multi-technology positioning

Combining LTE and BLE signals to keep location continuous where satellites can't reach.

Underground metro infrastructure equipped for worker location services
Operational benefits

Clear safety and operational benefits

Improved protection of field teams

For workers operating in underground and confined environments.

Real-time visibility

Across stations, tunnels and critical technical zones.

Reduced reaction time

In case of incident, through geolocated alerts.

Enhanced coordination

With emergency services when intervention is required.

Built for evolving projects

Adapted to large-scale and evolving transport infrastructure programmes.

The takeaway

Where positioning normally stops, continuous location keeps working - giving real-time visibility on every worker and geolocated alerts when seconds matter.

Partners Grand Paris Express Société des Grands Projets Kontron Equans
Your turn

If your teams work where GPS stops, location shouldn't

Tunnels, basements, plant rooms, confined technical areas - we can walk you through how continuous worker location works in the environments that defeat satellites.

  • Multi-technology positioning, no GNSS required
  • Runs on the professional devices teams already carry
  • Geolocated alerts for faster incident response
Talk to our team
Book a demo

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