Digital route model aided integrated satellite navigation
and low-cost inertial sensors for high-performance
positioning on the railways.
Doctoral thesis, UCL (University College London).
The basis of all railway signalling activities is the knowledge of the position and velocity of all trains in the system. The railways traditionally rely on train detection systems for this knowledge. However, the dependence of these systems on railway infrastructures limits their ability to cope with the advent of new high-speed lines and the development of freight networks across the Europe. Hence, there is a need for the introduction of modern positioning technologies into the railways. Unfortunately railways provide an unfriendly environment for satellite-based radio positioning systems (GNSS). For this reason it is common to integrate GNSS with low-cost inertial sensors (INS) but such systems cannot meet all railway positioning requirements. This thesis examines the potential of enhancing such an integrated GNSS/INS system with a digital route model (DRM). The study is carried out through a series of simulations of typical railway positioning scenes. A simulated database of GNSS, inertial and DRM data is built from real GPS data collected on a rail line between Norwich and Lowestoft. Several tests are first performed to test the validity of the database. Simulations are then done with a number of traditional INS/GPS integration architectures to test the possible performance of each system in the railway environment using lowcost INS sensors. The DRM-aiding is then realised through an integration with the GNNS/INS system via an extended Kalman Filter. Results from the study confirm the need for additional positioning information for an integrated system with low-cost inertial sensors to deal with difficult satellite signal situations such as tunnels, deep cuttings and covered stations. It is shown that a DRM leads to significant improvements in the overall system positioning performance. Also the optimal configuration, in terms of point spacing and accuracy, for a digital route model is selected from amongst simulated candidates.
|Title:||Digital route model aided integrated satellite navigation and low-cost inertial sensors for high-performance positioning on the railways|
|Open access status:||An open access version is available from UCL Discovery|
|UCL classification:||UCL > School of BEAMS > Faculty of Engineering Science > Civil, Environmental and Geomatic Engineering|
Archive Staff Only