Train positioning without blind spots

Tunnels, cuttings and stations block GNSS exactly where precise position matters. We help design and test positioning that keeps working between fixes.

WHO
Suppliers and operators
TYPICAL WORK
Fusion design, testing
START WITH
A fusion review
Talk about your projectDownload a sample report
A train in a tunnel passing radio beacons, above a chart in which position error grows between beacons and resets at each one, compared with dead reckoning alone drifting upward.

WHERE GNSS BITES

Common problems in rail

TUNNELS

No sky for minutes

Underground and in deep cuttings GNSS is gone, and position has to be carried by other sensors.

ODOMETRY

Wheel slip and slide

Odometry drifts under braking and in poor adhesion, so distance travelled can’t be taken on trust.

INTEGRITY

Knowing when to trust it

Safety functions need a position with honest error bounds, not just a best guess.

HOW WE HELP

What a project with us covers

  • A review of your positioning architecture and sensor choices
  • Fusion of GNSS, odometry, inertial sensors and trackside references
  • Error bounds that hold up through tunnels and stations
  • Replay testing on recorded runs from your own routes
  • Reports written to support your safety case
Map-style diagram of a route through a city, under a river in a tunnel and out again, with satellite fixes before and after, growing uncertainty ellipses while inside the tunnel, and a small chart of position error rising then resetting when the fix returns.
FIG. — Through a tunnel, position is carried forward by inertial and odometry data until the next fix. Illustrative.

SAMPLE REPORT

See exactly what you’ll receive

A sample report for each service, written for a fictional system: structure, findings format and recommendations. Illustrative data.

Download sample PDF

FAQ

Common questions

Do you work trackside?

Most work uses data you already record. Trackside trials can be added, run under your own access and safety arrangements.

SERVICES

Where to start

02

Sensor fusion & filter design

Kalman and particle filters, IMU calibration and multi-sensor integration for drones, robots and vehicles.

From £{x} · scoped per project

03

Navigation testing & evaluation

Independent simulation and test campaigns that show how your positioning really holds up.

From £{x} · per campaign

Working on rail positioning?

Send a few lines about the system and the route. You’ll get a reply within two working days.

dan@bearingandfix.co.uk