Railway positioning

• What is railway positioning?
• Market characteristics
• Use cases
• Challenges in railway positioning
• Key technologies
• The u-blox offering
• Why partner with u-blox
• The future of rail positioning

Enabling continuous positioning for a connected rail future

Rail networks demand precise and resilient navigation services to support a wide range of digital services, from scheduling to automation. For railway operators, system integrators, and OEMs, continuous train positioning technology enables greater operational efficiency, improved safety, and an enhanced passenger experience.

This page explores how railway positioning works, the challenges it addresses, and the technologies that make it possible - from GNSS and dead reckoning to correction services and integrated hardware solutions from u-blox.

 

What is railway positioning and why does it matter?

As railway networks modernize, the demand for accurate real-time position data grows. Continuous position availability of each train in the network is essential for a wide range of systems, including fleet management, live train tracking, train control, predictive maintenance, and passenger information. When the data delivered is trustworthy, train positioning supports safer operations, optimized traffic flow, and more reliable service delivery.

As automation, connectivity, and sustainability reshape rail operations, continuous positioning is becoming a cornerstone technology.

Market characteristics

The rail market is considered a sub-segment of public transport, covering long-distance and commuter trains as well as trams/streetcars.

It is an incredibly fragmented market, with nearly every country having its own operators. These operators typically look for long-term product availability, when evaluating rail positioning solutions, and for backwards compatibility with older products, to minimize the design requirements when a product gets discontinued.

Unsurprisingly, it’s very common that operators ask for solutions they can retrofit into existing rolling stock, to maximize the value of their investment in trains.

According to Mapsted, the railway telematics market is projected to grow to $6.38 billion in 2028, thanks to the push for smart railways, and the rise in IoT-based systems. Rail positioning specifically is part of a larger ecosystem of station navigation, passenger-facing apps, and AI route optimization for dispatchers and control rooms – these are all products and systems that train positioning solutions may need to integrate and communicate with. 

Systems requiring railway positioning technology

Challenges in railway positioning

Railway environments present a unique set of challenges for positioning technologies. Tunnels, covered stations, and urban canyons frequently block GNSS signals, while complex rail infrastructure can reflect or distort them. 

Normally, a localization solution would use dead reckoning to mitigate issues with GNSS signals. But train movement dynamics, such as slow acceleration coupled with high speeds, limited turning, and directional reversals require specialized algorithms that differ from automotive or aerial models.

Integrating rail positioning systems across existing fleets also demands careful consideration. Many trains still rely on legacy technologies and hardware, such as antennas that only support a few GNSS bands. Implementing GNSS-based solutions requires ensuring compatibility, reliability, and ease of maintenance. The challenge extends beyond accuracy to include continuity, integrity, and resilience against interference or jamming.

Technologies enabling railway positioning

GNSS technology

Global Navigation Satellite Systems (GNSS) form the foundation of most positioning systems, providing position, velocity, and timing data for moving vehicles. Multi-constellation and multi-band GNSS receivers enhance accuracy and reliability, while advanced filtering and interference mitigation help maintain signal quality in challenging environments.

In railway environments, GNSS still forms the foundation for continuous positioning. But due to the prevalence of environments where GNSS signals are weak or blocked on the railways, additional localization technologies are required. Additionally, many legacy GNSS systems only support the GNSS L1 band, or even just GPS. There is a clear need to modernize these systems to improve reliability and robustness.

Dead reckoning and the railway dynamic model

Dead reckoning complements GNSS by maintaining accurate position estimates when satellite visibility is poor. Dead reckoning uses an inertial measurement unit (IMU) to calculate changes in angular momentum and acceleration, which in turn are used to calculate a range of estimates about a vehicle's heading, orientation, and movement.

In rail localization, the main challenge with dead reckoning is developing a railway-specific model that accounts for train motion characteristics, to maximize the accuracy of the data the IMU provides.

Sensor fusion and map-matching

Advanced algorithms fuse data from inertial sensors, odometers, and digital track maps to improve the reliability of a positioning solution. Map-matching ensures position estimates align with the known rail network, enhancing accuracy.

 

The u-blox offering

u-blox offers a portfolio of GNSS modules tailored for railway applications, from standard to high precision. These solutions are designed for non-safety-critical systems or to act as redundancy for certified railway control and safety mechanisms.

Our technologies for rail positioning fall into three categories:

Standard Precision GNSS (SPG)

SPG solutions are designed for robust, energy-efficient positioning at meter-level accuracy. They typically use single- or dual-frequency GNSS signals and are optimized for reliable tracking under good satellite visibility. SPG is ideal for scalable applications such as fleet monitoring and asset management.

High Precision GNSS (HPG)

HPG technologies enhance GNSS accuracy to the centimeter level through correction data methods such as Real-Time Kinematics (RTK) and Precise Point Positioning (PPP). Multi-band, multi-constellation support provides fast convergence and reliable operation, even in environments with signal interference. HPG is essential for applications requiring deterministic accuracy, including precision track monitoring, and detecting changes in wheel diameter by comparing the defined wheel diameter with the distance travelled.

Dead Reckoning (DR)

Dead reckoning maintains positioning continuity when GNSS signals are degraded or unavailable, using motion data from accelerometers, gyroscopes, and odometers. This enables uninterrupted positioning through tunnels, dense stations, or urban canyons. DR ensures reliable and consistent data streams for control and monitoring systems, supporting predictive maintenance and depot management.

All modules share a common design philosophy: robust performance, easy integration, and long-term availability. Backed by powerful tools and global technical support, they provide a future-proof foundation for railway positioning solutions.

Below is an overview of the available models recommended for design-in at the time of writing and their capabilities across Standard Precision GNSS (SPG), High Precision GNSS (HPG), and Dead Reckoning (DR) functionalities:
 

Model	SPG	HPG	DR	Bands
ZED-F9R	✓	✓*	✓	L1/L2
ZED-F9P	✓	✓		L1/L2
NEO-F9P	✓	✓		L1/L5
NEO-F10N	✓			L1/L5
MIA-M10Q	✓			L1
MAX-M10N	✓			L1
NEO-M9N	✓			L1

*Supported without specified performance for use on railways 

Why partner with u-blox?

u-blox understands the value of design stability. That’s why our products remain in production for years, if not decades – our M8 platform, for instance, has been in production since 2013, much longer than typical commercial semiconductor chips and modules. We also design new products with the same form factors as the older versions for easy integration.

In addition to our hardware, u-blox offers services that extend the value of your railway positioning hardware. By using correction, assistance, and configuration tools from the same single trusted partner as your hardware, you can enjoy seamless integration, reduced development effort, and consistent high performance across the rail ecosystem.

AssistNow

AssistNow is a cloud-based service that reduces the time it takes GNSS receivers to acquire a position fix. By providing satellite data over the internet rather than relying solely on broadcast signals, it improves performance in environments where visibility is limited – such as stations, tunnels, or dense urban areas. For rail operators, this means faster start-up times and more reliable positioning, even in challenging locations.

PointPerfect

PointPerfect delivers high-precision GNSS correction data with centimeter-level accuracy using secure cloud delivery. This service enhances HPG applications by maintaining consistent accuracy across large networks, supporting advanced train control and automation systems. For operators, it ensures that trains can be precisely located in places such as shunting yards, where multiple tracks are located next to each other.

u-center

u-center is a configuration and evaluation tool that simplifies the setup, testing, and optimization of GNSS receivers. It provides engineers with real-time visualization and diagnostic capabilities, making it easier to integrate hardware and fine-tune performance for railway use cases. In combination with AssistNow and PointPerfect, it supports faster development and deployment cycles.

The future of rail positioning

As rail networks evolve toward automation, continuous train positioning technologies will continue to be refined. Future advancements will focus on scalable correction services, resilient algorithms, and deeper integration with rail control systems such as ETCS and ATO. Meanwhile, backwards compatibility and the ability to rely on components for years or even decades will be important for ensuring that operators can modernize their fleets cost-effectively.

By combining GNSS, dead reckoning, and cloud-based correction services, u-blox is helping rail operators navigate toward a safer, smarter, and more connected future. Dead reckoning for rail simplifies things for operators by ensuring they get consistent and reliable location data, anywhere in the network, from a single system. And with product lifecycles measured in the decades, and consistent form factors for easy upgrading, u-blox products are the ideal foundation of a long-term rail positioning solution.