5G Geopositioning in Real-World Testing – New Insights from a Tunnel Environment

Last year, together with our partners, we demonstrated in an early field test how 5G geopositioning performs outside the laboratory under real-world conditions. At that time, the main focus was on how reliably positions can be determined in complex, practical environments and what role modern IT infrastructure and antenna technologies play in this context.

With the current test, we have consistently continued this approach and taken a closer look at a particularly demanding scenario: an underground infrastructure in the form of a newly constructed railway tunnel in southern Germany.

Together with our partners FBI GmbH, IALTAG GmbH, Hochschule Aalen and ConnectingCase GmbH, we investigated how 5G, DECT and WiFi signals behave in an environment defined by highly specific technical and physical constraints.

The key question: waveguide or attenuation trap?

At the core of the test was a fundamental question regarding radio wave propagation in tunnel environments:

Does a tunnel structure behave like a waveguide that efficiently transports signals over longer distances? Or does the signal energy decay as quickly as in free space once there is no direct line of sight?

This question is highly relevant for future applications in communication, positioning, safety, logistics and infrastructure monitoring in underground environments.

Test setup

The test was carried out in a realistic section of the newly constructed tunnel, including both complex curved areas without direct line of sight and long straight segments. In addition, the environment included level as well as ascending and descending sections.

The setup included, among other components, innovative antennas from IALTAG, specifically designed for demanding radio environments.

The goal was to compare the performance of different technologies (DECT, 5G and WiFi) under real conditions and, in particular, to analyse how signal range develops along the tunnel structure.

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Surprising real-world results

The measurement results significantly exceeded initial expectations and clearly demonstrate how radio wave propagation behaves in tunnel structures:

• In complex tunnel sections with inclines and curves – without direct line of sight – a 3 to 4 times greater range compared to free space was achieved.
• Even behind the antennas, an additional range of up to 150 metres could still be measured.
• On straight tunnel sections, a particularly striking effect was observed: the range was 8 to 10 times greater than in free space. 

These results suggest that tunnel structures can, in certain scenarios, exhibit waveguide-like properties and propagate signals significantly more efficiently than in open environments.

What does this mean for 5G geopositioning?

The findings are highly relevant for the further development of 5G geopositioning and communication solutions in enclosed infrastructure environments.

They show that:

• tunnel environments can actively support radio wave propagation,
• signal ranges may be more predictable than previously assumed,
• and new opportunities for geopositioning emerge when infrastructure design and antenna technology are optimally aligned. 

This brings the vision of reliable, continuous positioning in critical infrastructure environments a significant step closer.

Conclusion and outlook

The latest test clearly confirms that real tunnel environments exhibit fundamentally different radio behaviour compared to traditional free-space scenarios. At the same time, the results open up new perspectives for the use of 5G geopositioning in infrastructure projects – from construction and maintenance processes to safety-critical applications.

Together with our partners, we aim to further develop this approach and translate the findings into future pilot projects and real-world applications.

Our partners at a glance

FBI GmbH
FBI GmbH is an experienced partner for specialised communication and technology solutions in the field of critical infrastructure. With strong technical expertise, the company supports projects from planning through to implementation in real-world environments.

IALTAG GmbH
IALTAG is a specialist in innovative antenna technologies. Its antenna solutions are designed specifically for complex environments such as tunnels, industrial facilities and hard-to-access areas.

Hochschule Aalen
Hochschule Aalen contributes its expertise in telecommunications, sensor technology and applied research to the project. It supports the analysis of complex radio propagation conditions and helps to scientifically evaluate and further develop real-world measurement results. This provides an important contribution to assessing 5G geopositioning technologies in real infrastructure scenarios.

ConnectingCase GmbH
ConnectingCase develops modular and flexible system solutions for demanding operational scenarios. The focus lies on robust mobile infrastructure concepts for industrial and public applications.