Functional, thermal and EMC analysis for a safety critical analogue design applied to a transportation systems

Safety-critical equipment depends on the study of functional, thermal, EMC (Electromagnetic Compatibility) and RAMS (Reliability, Availability, Maintainability and Safety) fields. The variation of one area characteristic could result in a failure to fulfil safety requirements. Traditionally, thermal, EMC or RAMS issues were only considered once the design was done. This paper proposes a novel analogue equipment design methodology by studying these areas dependently from the beginning of the design process. Each area requirements and design parameters and the relation among them are defined qualitatively and quantitatively. Based on these dependences among all the areas, the cross-influence of each parameter variation in other areas requirements is demonstrated. The obtained results are intended to aid the fulfilment of requirements of the design of any safety critical analogue circuit, and to help designers to know beforehand the consequences of any change in the design, saving time and money. The application of this methodology in a SIL 2 RF transmitter is shown and the improvement and worsening of requirements depending on the parameters variation is exposed

An enhanced integrity multisensor Fusion for a reliable seamless navigation.

Since its first applications in the late 20th century, GNSS technology has been deployed by the world’s technologically advanced countries in multiple fields, from fleet monitoring to sport-related topics. This massive deployment has led to new use cases that may not have been expected during the definition of said technology. Different error sources, such as interferences, jamming, signal attenuation due to indoor or urban canyon navigation, and signal-blocking objects may degrade the performance of GNSS-based navigation. Thus, standalone GNSS systems may not fulfil all the requirements a certain scenario might ask for. This has resulted in the research of alternative or supplementary methods to solve the aforementioned issues, such as multisensor navigation. This has become one of the main alternatives to GNSS standalone navigation, as it has been shown in the literature that it can result in an improvement in navigation in terms of availability or continuity, for example. Human-life involvement and high-cost freight transportation, among other factors, have attracted the attention of the users to the definition of a measure of trust that is placed in the correctness of the information supplied by the navigation systems; also called integrity. This concept is employed, among others, to enable the system to detect if it is trustable for navigation, provide warnings, and even act consequently. In this dissertation, we analyze, first, the design of an online multisensory navigation algorithm as a solution to the issues GNSS suffers especially in urban and indoor environments. Moreover, a two-stage integrity-ensuring method is analyzed, being this second algorithm a tailored complementary feature of the proposed navigation one.Desde sus primeras aplicaciones a fines del siglo XX, la tecnología GNSS ha sido implementada por los países tecnológicamente avanzados del mundo en múltiples campos, desde la monitorización de flotas hasta temas relacionados con el deporte. Este despliegue masivo ha dado lugar a nuevos casos de uso no contemplados durante la definición de dicha tecnología. Diferentes fuentes de error, como interferencias, atenuación de la señal debido a la navegación en interiores o en cañones urbanos y objetos que bloquean la señal pueden degradar el rendimiento de la navegación basada en GNSS. Por lo tanto, es posible que los sistemas basados únicamente en GNSS no cumplan con todos los requisitos que podría solicitar un determinado escenario. Esto ha dado lugar a la investigación de métodos alternativos o complementarios para solucionar los problemas antes mencionados, como la navegación multisensor. Ésta se ha convertido en una de las principales alternativas a la navegación autónoma GNSS, ya que se ha demostrado en la literatura que puede resultar en una mejora en la navegación en términos de disponibilidad o continuidad, por ejemplo. La afectación de la vida humana y el transporte de carga de alto costo, entre otros factores, han llamado la atención de los usuarios sobre la definición de una medida de confianza que se deposita en la exactitud de la información suministrada por los sistemas de navegación; también llamada integridad. Este concepto se emplea, entre otros, para que el sistema detecte si es fiable para la navegación, emita avisos e incluso actúe en consecuencia. En esta tesis analizamos, en primer lugar, el diseño de un algoritmo de navegación multisensorial online como solución a los problemas que sufre el GNSS especialmente en entornos urbanos e interiores. Además, se analiza un método de aseguramiento de la integridad en dos etapas, siendo este segundo algoritmo una característica complementaria a la medida del de navegación propuesto

An enhanced integrity multisensor Fusion for a reliable seamless navigation.

Since its first applications in the late 20th century, GNSS technology has been deployed by the world’s technologically advanced countries in multiple fields, from fleet monitoring to sport-related topics. This massive deployment has led to new use cases that may not have been expected during the definition of said technology. Different error sources, such as interferences, jamming, signal attenuation due to indoor or urban canyon navigation, and signal-blocking objects may degrade the performance of GNSS-based navigation. Thus, standalone GNSS systems may not fulfil all the requirements a certain scenario might ask for. This has resulted in the research of alternative or supplementary methods to solve the aforementioned issues, such as multisensor navigation. This has become one of the main alternatives to GNSS standalone navigation, as it has been shown in the literature that it can result in an improvement in navigation in terms of availability or continuity, for example. Human-life involvement and high-cost freight transportation, among other factors, have attracted the attention of the users to the definition of a measure of trust that is placed in the correctness of the information supplied by the navigation systems; also called integrity. This concept is employed, among others, to enable the system to detect if it is trustable for navigation, provide warnings, and even act consequently. In this dissertation, we analyze, first, the design of an online multisensory navigation algorithm as a solution to the issues GNSS suffers especially in urban and indoor environments. Moreover, a two-stage integrity-ensuring method is analyzed, being this second algorithm a tailored complementary feature of the proposed navigation one.Desde sus primeras aplicaciones a fines del siglo XX, la tecnología GNSS ha sido implementada por los países tecnológicamente avanzados del mundo en múltiples campos, desde la monitorización de flotas hasta temas relacionados con el deporte. Este despliegue masivo ha dado lugar a nuevos casos de uso no contemplados durante la definición de dicha tecnología. Diferentes fuentes de error, como interferencias, atenuación de la señal debido a la navegación en interiores o en cañones urbanos y objetos que bloquean la señal pueden degradar el rendimiento de la navegación basada en GNSS. Por lo tanto, es posible que los sistemas basados únicamente en GNSS no cumplan con todos los requisitos que podría solicitar un determinado escenario. Esto ha dado lugar a la investigación de métodos alternativos o complementarios para solucionar los problemas antes mencionados, como la navegación multisensor. Ésta se ha convertido en una de las principales alternativas a la navegación autónoma GNSS, ya que se ha demostrado en la literatura que puede resultar en una mejora en la navegación en términos de disponibilidad o continuidad, por ejemplo. La afectación de la vida humana y el transporte de carga de alto costo, entre otros factores, han llamado la atención de los usuarios sobre la definición de una medida de confianza que se deposita en la exactitud de la información suministrada por los sistemas de navegación; también llamada integridad. Este concepto se emplea, entre otros, para que el sistema detecte si es fiable para la navegación, emita avisos e incluso actúe en consecuencia. En esta tesis analizamos, en primer lugar, el diseño de un algoritmo de navegación multisensorial online como solución a los problemas que sufre el GNSS especialmente en entornos urbanos e interiores. Además, se analiza un método de aseguramiento de la integridad en dos etapas, siendo este segundo algoritmo una característica complementaria a la medida del de navegación propuesto

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

Innovation-based fault detection and exclusion applied to ultra-wideband augmented urban GNSS navigation

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

Freight train in the age of self-driving vehicles. A taxonomy review

Recently, the first successful deployment of a fully automated commercial freight train operation was announced. This is the world's first automated heavy-duty and long-haul rail network. It's an impressive achievement, but why has it taken so long to achieve this when driverless urban metros have been in operation for more than 50 years? Although urban metros and freight trains are vehicles moved on rails, their operation and environment differ significantly. Metros operate in closed rail networks, while freight trains operate in open rail networks. However, the same taxonomy is often used to classify automation interchangeably in both environments. This paper provides context and an overview of driving automation in freight rail and reviews the existing taxonomies. This paper starts by providing context with an overview of the general process of driving a vehicle by delimiting its different stages. Next, we describe the overall process of driving a freight train to show the distinctive features of its setup and operation. In this analysis, we will point out the essential differences between open and closed rail networks, and the tasks that can potentially be automated. Additionally, we examine the evolution of level-based automation taxonomies and review those that have been proposed exclusively for driving automation in open and closed railway networks. Our objective is to provide a thorough summarization of the most relevant taxonomies to advance the definition of a suitable taxonomy and framework to classify automation capabilities in rail freight transport and identify some complex challenges ahead

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

Map-aided software enhancement for autonomous GNSS complementary positioning system for railway

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

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