Physics

GNSS applications

Inertial measurement unit

GLONASS

Operating system

Inertial navigation system

Geodesy

Engineering

Inertial frame of reference

Artificial intelligence

Geography

Precise Point Positioning

Computer science

Global Positioning System

Quantum mechanics

Real-time computing

Odometer

Simulation

Remote sensing

Telecommunications

Track (disk drive)

GPS Solutions

Precise track irregularity measuring is a pivotal technique to protect dynamic safety for railway transportation applications, especially those on high-speed railways. Current methods, such as the total station-based automatic inspection systems, commonly have a high cost and are inefficient. To reduce the costs and improve the measuring efficiency, a multi-sensors fusion system consisting of multi-constellation global navigation satellite systems (GNSS)-based precise point positioning, inertial navigation system, odometer, and track gauge is proposed and is further enhanced by using the Rauch–Tung–Striebel smoother. By using this system, one not only obtains high measuring accuracy, but also obtains increased efficiency of track irregularity measuring tens of times than achieved by conventional methods. After the principle investigations, a set of high-speed railway track measuring data containing quad-GNSS (GPS, BDS, GLONASS, and Galileo) observations, laser inertial measurement unit data, odometer measurements, and track gauge data are processed and analyzed to evaluate the capability of the proposed system. The results illustrate that the proposed system, which provided approximately 0.25, 0.59, 0.65, and 0.48 mm measuring accuracy in the super elevation, horizontal, vertical, and gauge components, respectively, can be used for high-accuracy track irregularity measuring.

Railway irregularity measuring using Rauch–Tung–Striebel smoothed multi-sensors fusion system: quad-GNSS PPP, IMU, odometer, and track gauge