Due to their ability to provide a worldwide absolute outdoor positioning, Global Navigation Satellite Systems (GNSS) have become a reference technology in terms of navigation technologies. Transportation-related sectors make use of this technology in order to obtain a position, velocity, and time solution for different outdoor tasks and applications. However, the performance of GNSS-based navigation is degraded when employed in urban areas in which satellite visibility is not good enough or nonexistent, as the ranging signals become obstructed or reflected by any of the numerous surrounding objects. For these situations, Ultra-Wideband (UWB) technology is a perfect candidate to complement GNSS as a navigation solution, as its anchor trilateration-based radiofrequency positioning resembles GNSS's principle. Nevertheless, this fusion is vulnerable to interferences affecting both systems, since multiple signal-degrading error sources can be found in urban environments. Moreover, an inadequate location of the augmenting UWB transmitters can introduce additional errors to the system due to its vulnerability to the multipath effect. Therefore, the misbehavior of an augmentation system could lead to unexpected and critical faults instead of improving the performance of the standalone GNSS. Accordingly, this research work presents the performance improvement caused by the application of Fault Detection and Exclusion methods when applied to a UWB-augmented low-cost GNSS system in urban environments.

In the above article [1], the authors forgot to properly acknowledgment the Shift2Rail Joint Undertaking.

The digitalisation of freight rail is an essential improvement to create modern functions that offer a cost-effective, attractive service and improved operational opportunities to operators. These modern functions need intelligence, detection, actuation and communications. For this, generally, it is possible to process raw data in the Edge and send meaningful data over a communication link. However, the power supply is not granted in a freight wagon and so low power strategies need to be adopted. This paper presents the implementation and testing of a wireless connected heterogeneous multiprocessing architecture. From the power consumption point of view, this system has been stressed by means of a generic FFT function to evaluate the different on-board computing devices that have been decided. From the communication point of view, the LPWAN LoRa technology has been tested and validated on robustness and coverage. Thanks to the heterogeneous nature of this architecture and its configurability, it allows us to propose the most suitable computing ressources, data analysis and communication strategy in terms of efficiency and performance for the functions that this wagon on board unit needs to host and support. With this approach, operation data are reported to the centralised freight driver assistant system.

Electromagnetic (EM) disturbances and compatibility issues are the most common problems affecting communication and signaling systems. The duration of field testing to solve these railway EM interference (EMI) problems may vary between three and 12 months, with the cost of the complete process between & euro;25,000 and & euro;1.5 million [1]. Currently, the railway industry demands the building of strategies and tools to promote paths toward zero on-site testing [2] and reduce the duration of field tests; however, there is a lack of laboratory testing resources for these approaches.

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.

A malicious attack on a safety-critical system can derive in an undesired behavior of the system that may result in a failure. In this case, the reliability of the device is decreased, and it might affect directly to safety. Therefore, the security is also an essential issue to consider in the design of safety-critical systems. The main problem when safety and security are considered is to make them work together without interfering each other. A safety-critical device needs to be certified following standards like IEC-61508, and any security mechanisms must not affect this certification. This paper describes a system that integrates safety and security mechanisms to improve reliability without affecting safety certification. With the aim of reaching the required safety level, a redundant system is considered. This system is an n out of m distributed and synchronized voter. The synchronization method is based on the precision time protocol (IEEE-1588) allowing that all devices on a local network have the same time.

Independently on the business case addressed, one of the main drawbacks of the railway use cases that need continuous Global Navigation Satellite Systems data is the lack of availability for the 100% of the time of the journey. Additionally, the integrity assessment of the position estimation given is also mandatory for safety critical applications. Thus, tunnels and multipath effects are one of the most challenging situations for the continuous positioning systems. In this context, an autonomous on-board Complementary Positioning System has been proposed to overcome the limitation of Global Navigation Satellite System based positioning systems. This paper proposes a positioning enhancement solution by means of fusing data from the satellite navigation system and inertial measurement units. That hybrid solution provides higher availability and accuracy to the positioning specially on known blocked scenarios, such as tunnels, or urban canyons, by means of a novel environment aware map aided software technique named Known Blocked Scenarios algorithm... This paper describes the Complementary Positioning System and the field test carried out in a challenging environment to validate the enhancement proposed by the authors, which demonstrate the benefits that this system has in known harsh environments for railways.

Most critical applications today depend on computers, so a computer failure can cause financial disaster, serious injury, or even death. In this context, railways are considered a critical application, so they must meet the highest standards of availability and safety. Availability ensures continuous operation of the system, while a safe system must behave correctly in all operating and environmental conditions.

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.

It is necessary to verify the faults tolerance of the European Train Control System (ETCS) on-board unit even if these faults are uncommon. Traditional test methods defined and used in ETCS do not allow to check this, so it is necessary to develop a new mechanism of tests. This paper presents the design and implementation of a saboteur applied to the railway sector. The main purpose of the saboteur is the fault injection in the communication interfaces. By means of a virtual laboratory it is possible to simulate actual train journeys to test the ETCS on-board unit. Making use of the saboteurs andthe virtual laboratory it is possible to analyse the behaviour of the train in the presence of unexpected faults, and to verify that the decisions taken are correct to ensure the required safety level. Therefore, this work shows a testing strategy based on different kinds of train journeys when faults are injected, and the analysis of the results.

This chapter provides guidelines on modelling the smart low¿cost near¿field wireless objects and on how to integrate their behavior in traditional network discrete event simulation (DES) tools. The ultimate aim is to provide an insight into the available tools in order to study their behavior and their impact on the access and core communication infrastructures of intelligent transportation system (ITS). The chapter details the two most common near¿field wireless technologies, including radio frequency identification (RFID) and near¿field communication (NFC). Currently two different approaches can be distinguished regarding the characterization of near¿field communications, namely theoretical calculations based on electrical models and electromagnetic simulators. As a result of the characterization, a transfer function of the near¿field communication is obtained. This transfer function can be employed in the DES framework as the model of the link level near¿field zone between the communication devices.

The electromagnetic interferences (EMI) are threats that affect the reliability of the railway signalling systems. Consequently, the identification of the reliability requirements dependent on environment conditions is a major issue for signalling systems designers, and therefore for evaluators, and testing and certification bodies. Signalling systems work in the complex and heterogeneous railway environment, where low power electronics have to work together with high voltages and currents from trains and railway infrastructure. This chapter presents the relationship between the railway electromagnetic interoperability and the reliability assessment by analyzing the signalling systems and the associated inter-dependencies with other components of the rolling stock. It is composed of two main sections; the first gathers an exhaustive state of the art approach to the issue of electromagnetic interoperability and railway industry. This subsection steers towards the combination of electromagnetic interferences and the signalling systems present in the rolling stock noise environment. That is the basis of the second section that finally sets how to establish the reliability requirement for a communication path in this environment. This requirement is established because of the electromagnetic noise environment, as well as the radiated and conducted fields, which are a combination of all the surrounding threats a focused railway system has to face.