Multi-sensor fusion for seamless navigation in railway domain.

The European Union (EU) aims at making railway a more attractive transportation method by improving its efficiency and reducing its costs. These achievements could be covered with the migration from ETCS level 2 to ETCS level 3. Many projects related to new positioning systems have been funded by The European Union. Most of these positioning systems are based on GNSS, due to the key role that GNSS will play in the migration to ETCS level 3. One of the problems on using only GNSS systems is the lack of availability of them. During railway operation, there are areas with potential GNSS outages, such as urban canyons, woods or other possible signal blockers and disturbances. Moreover, it is a fact that GNSS signals are not reachable, nor reliable in tunnels or indoor environments. For GNSS to be able to have a key role in the next years in railway security, the afore mentioned lack of availability has to be solved. To cope with this issue, a multi-sensor approach with software enhancements is proposed in this dissertation. The objective of this research work deals with fusing different sensors and creating new software strategies to achieve a higher availability with the best possible accuracy. The seamless position will benefit in all the operation modes, from the train station to a harsh environment for satellites, during the train operation. The scope of the dissertation is to create a multi-sensor positioning system including GNSS, Inertial Measurement Unit (IMU), and Ultra Wide Band (UWB) with other software techniques to obtain a position estimation with a 100% availability for railway systems. This work shows the different steps from the study of the state of the art, going through the implementation, and ending with the performance analysis of the algorithm developed. This research work has been conducted under different European projects such as ERSAT-EAV, FR8RAIL or X2Rail-2, in which CEIT has participated

Residual based fault detection and exclusion methods applied to Ultra-Wideband navigation.

Global Navigation Satellite System (GNSS) has become the main technology in terms of navigation technologies, as it ensures a worldwide absolute outdoor positioning. The transportation sector employs this technology to obtain a position, velocity and time solution for the corresponding outdoor application. When talking about indoor positioning, nevertheless, GNSS becomes an unreliable navigation technology, as the below-noise signals get obstructed. In these cases, the Ultra-Wideband (UWB) technology can be used as a navigation solution, as its anchor trilateration based radiofrequency positioning resembles GNSS's principle and, depending on the anchor location, it can be used for indoor positioning. However, just like other radiofrequency based technologies, UWB is vulnerable to interferences and the multipath effect. With the aim of overcoming these drawbacks, this article discusses how to apply Fault Detection and Exclusion (FDE) techniques to avoid using faulty anchors when employing UWB in indoor/urban environments such as tunnels or train stations

Alarm collector in smart train based on ethereum blockchain events-log.

The European Union is moving toward the "smart" era having as one of the key topics the smart mobility. What is more, the European union (EU) is moving toward Mobility as a Service (MaaS). The key concept behind MaaS is the capability to offer both the traveler's mobility and goods' transport solutions based on travel needs. For example, unique payment methods, intermodal tickets, passenger services, freight transport services, etc. The introduction of new services implies the integration of many Internet-of-Things (IoT) sensors. At this point, security gains a key role in the railway sector. Considering an environment where sensor data are monitored from sensor events, and alarms are detected and emitted when events contain an anomaly, this document proposes the development of an alarms collection system, which ensures both traceability and privacy of these alarms. This system is based on Ethereum blockchain events-log, as an efficient storage mechanism, which guarantees that any railway entity can participate in the network, ensuring both entity security and information privacy

Methodology and key performance indicators (KPIs) for railway on-board positioning systems

The European Union (EU) is bolstering the railway sector with the aim of making it a direct competitor of the aviation sector. For that to occur, railway efficiency has to be improved by means of increasing capacity and reducing operational expenditure. Tracks are currently used below their maximum capacity. Given this fact and the EU's goals for the railway sector, research on solutions for on-board positioning system based on global navigation satellite systems (GNSS) have arisen in recent years. By taking advantage of GNSS, safety critical positioning systems will be able to use the infrastructure more efficiently. However, GNSS based positioning systems still cannot fulfill current normative validation processes, mainly, due to the fact that GNSS based positioning performance evaluation is not compatible with the key performance indicators (KPIs) used to assess railway systems performance: reliability, availability, maintainability, and safety. This paper proposes a methodology and unified key performance indicators (KPIs). Additionally, it shows real examples to address this issue. It aims to fill the gap between the current railway standardization process and any on-board positioning system