Revistas
Revista:
REMOTE SENSING
ISSN:
2072-4292
Año:
2023
Vol.:
15
N°:
1
Págs.:
99 - *
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.
Autores:
Zabalegui, P. (Autor de correspondencia); de Miguel, Gorka; Pérez, A.; et al.
Revista:
IEEE ACCESS
ISSN:
2169-3536
Año:
2022
Vol.:
10
Págs.:
77522 - 77522
In the above article [1], the authors forgot to properly acknowledgment the Shift2Rail Joint Undertaking.
Revista:
ELECTRONICS
ISSN:
2079-9292
Año:
2022
Vol.:
11
N°:
6
Págs.:
943
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.
Autores:
Fernández-Berrueta, N. (Autor de correspondencia); Goya, Jon; Arrizabalaga, J.; et al.
Revista:
APPLIED SCIENCES
ISSN:
2076-3417
Año:
2022
Vol.:
12
N°:
1
Págs.:
345
Railway applications are in continuous evolution with the aim of offering a more efficient, sustainable, and safer transportation system for the users. Generally, these applications are constantly exchanging information between the systems onboard the train and the trackside through a wireless communication. Nowadays, Global System for Mobile communications-Railway (GSM-R) is the technology used by European Train Control System (ETCS), but it is becoming obsolete. Therefore, alternatives for this technology have to be found for the different railway applications. Its natural evolution is to move forward with the latest technology deployed: Long-Term Evolution (LTE), which the Public Land Mobile Networks (PLMN) have already deployed. Therefore, testing the performance of this communication technology in the railway environment could be useful to assess its suitability and reduce the cost of railway network dedicated deployment. In order to do that, a methodology to characterize the communication environment is proposed. The main goal is to measure geolocated impairments of any communication channel in a railway environment being able to determine its behavior of the different communication technologies and find out possible coverage issues. Moreover, it could help in the selection of suitable communication technology for railway. This paper presents a brief description of the communication for railways and its QoS parameters for performance measuring. Afterward, the testing methodology is described, and then, the communication channel measurement campaign on a real track in Spain where the railway environment is variable is presented (tunnels, rural/urban area horizontal ellipsis ). Finally, the measurements and results on this real track in Spain are shown. The results provide suitability of the 4G technologies based on the delay requirements for the implementation of ETCS over it.
Autores:
Franco, D.; Aguado, M.; Pinedo, C.; et al.
Revista:
IEEE VEHICULAR TECHNOLOGY MAGAZINE
ISSN:
1556-6072
Año:
2021
Vol.:
16
N°:
2
Págs.:
104 - 112
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.
Revista:
IEEE INTERNET OF THINGS JOURNAL
ISSN:
2327-4662
Año:
2021
Vol.:
8
N°:
17
Págs.:
13306 - 13315
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.
Revista:
IEEE ACCESS
ISSN:
2169-3536
Año:
2020
Vol.:
8
Págs.:
109266 - 109274
Communication technologies are in continuous evolution and as well, the different applications making use of them. In order to succeed with the roll-out of the communication-based applications, it is required that the communications technologies are intensively tested and validated before deployment. Current strategies for testing and validation cover field tests and laboratory tests. Railways is also taking advantage of the communication technologies evolution, and therefore, there is a need for having testing and validation strategies adapted to the railway environment, especially for safety-critical applications. Field tests and laboratory tests also apply in Railways. In the frame of laboratory tests, this paper includes an overview of different network emulators existing currently in the market. Furthermore, an analysis of the gaps of the network emulators with regards to the needs of the railways environment is also included. The goal of this paper is to show that network emulators are a flexible cost-effective solution for communication technologies testing purposes. Additionally, this paper also shows that there is a need to adapt current emulators to the railway environment in order to test and validate the future railway applications based on communication technologies.
Revista:
QUALITY AND RELIABILITY ENGINEERING INTERNATIONAL
ISSN:
0748-8017
Año:
2019
Vol.:
35
N°:
2
Págs.:
561 - 571
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.
Revista:
SENSORS
ISSN:
1424-8220
Año:
2019
Vol.:
19
N°:
23
Págs.:
5183
Inductor-capacitor (LC) passive wireless sensors are widely used for remote sensing. These devices are limited in applications where multiparameter sensing is required, because of the mutual coupling between neighboring sensors. This article presents two effective decoupling techniques for multiparameter sensing, based on partially overlapped sensors and decoupling coils, which, when combined, reduce the mutual coupling between sensors to near zero. A multiparameter LC sensor prototype with these two decoupling mechanisms has been designed, simulated, and measured. This prototype is capable of simultaneously measuring four parameters. The measurements demonstrate that the changes in capacitance in one individual sensor do not affect the measurements of the other sensors. This principle has been applied to simultaneous wear sensing using four identical wear sensors.
Revista:
IEEE TRANSACTIONS ON VEHICULAR TECHNOLOGY
ISSN:
0018-9545
Año:
2019
Vol.:
68
N°:
12
Págs.:
11611 - 11620
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.
Revista:
MULTIMEDIA TOOLS AND APPLICATIONS
ISSN:
1380-7501
Año:
2018
Vol.:
77
N°:
7
Págs.:
7977 - 8000
The popular Internet service, YouTube, has adopted by default the HyperText Markup Language version 5 (HTML5). With this adoption, YouTube has moved to Dynamic Adaptive Streaming over HTTP (DASH) as Adaptive BitRate (ABR) video streaming technology. Furthermore, rate adaptation in DASH is solely receiver-driven. This issue motivates this work to make a deep analysis of YouTube's particular DASH implementation. Firstly, this article provides a state of the art about DASH and adaptive streaming technology, and also YouTube traffic characterization related work. Secondly, this paper describes a new methodology and test-bed for YouTube's DASH implementation traffic characterization and performance measurement. This methodology and test-bed do not make use of proxies and, moreover, they are able to cope with YouTube traffic redirections. Finally, a set of experimental results are provided, involving a dataset of 310 YouTube's videos. The depicted results show a YouTube's traffic pattern characterization and a discussion about allowed download bandwidth, YouTube's consumed bitrate and quality of the video. Moreover, the obtained results are cross-validated with the analysis of HTTP requests performed by YouTube's video player. The outcomes of this article are applicable in the field of Quality of Service (QoS) and Quality of Experience (QoE) management. This is valuable information for Internet Service Providers (ISPs), because QoS management based on assured download bandwidth can be used in order to provide a target end-user's QoE when YouTube service is being consumed.
Revista:
IEEE VEHICULAR TECHNOLOGY MAGAZINE
ISSN:
1556-6072
Año:
2018
Vol.:
13
N°:
1
Págs.:
48 - 55
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.
Revista:
IEEE TRANSACTIONS ON INTELLIGENT TRANSPORTATION SYSTEMS
ISSN:
1524-9050
Año:
2018
Vol.:
19
N°:
12
Págs.:
4035 - 4042
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.
Revista:
PROMET-TRAFFIC AND TRANSPORTATION
ISSN:
0353-5320
Año:
2017
Vol.:
29
N°:
2
Págs.:
213 - 223
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.
Autores:
Rodriguez, L.; Pinedo, C.; Lopez, I.; et al.
Revista:
NETWORK PROTOCOLS AND ALGORITHMS
ISSN:
1943-3581
Año:
2016
Vol.:
8
N°:
1
Págs.:
58 - 72
The evolution of the railway sector depends, to a great extent, on the deployment of advanced railway signalling systems. These signalling systems are based on communication architectures that must cope with complex electromagnetical environments. This paper is outlined in the context of developing the necessary tools to allow the quick deployment of these signalling systems by contributing to an easier analysis of their behaviour under the effect of electromagnetical interferences. Specifically, this paper presents the modelling of the Eurobalise-train communication flow in a general purpose simulation tool. It is critical to guarantee this communication link since any lack of communication may lead to a stop of the train and availability problems. In order to model precisely this communication link we used real measurements done in a laboratory equipped with elements defined in the suitable subsets. Through the simulation study carried out, we obtained performance indicators of the physical layer such as the received power, SNR and BER. The modelling presented in this paper is a required step to be able to provide quality of service indicators related to perturbed scenarios
Revista:
MEASUREMENT
ISSN:
0263-2241
Año:
2016
Vol.:
77
Págs.:
124 - 131
The interoperability between on track balises and the on board Balise Transmission Module systems depends on both sides' susceptibility and allowed emissions. For that assessment, the document that governs the testing methodology, tools and procedures (Subset 116) needs to be completed prior to its publication. The present paper proposes an advance beyond the state of the art for the rolling stock emission assessment in terms of the test setup and of the post-processing procedure. The documentation commonly used in ERTMS-related issues has been analyzed and the common tools and procedures have been taken into consideration for the proposal presented by the authors. (C) 2015 Elsevier Ltd. All rights reserved.
Revista:
LECTURE NOTES IN COMPUTER SCIENCE
ISSN:
0302-9743
A SDK (Software Development Kit) to test, develop or improve safety-critical systems is presented. The SDK has three main modules: voter, saboteur and sniffer. The voter can be configured as ¿m out of n¿ where m and n can be any number but always n > m, each redundant channel uses a microcontroller as a main system. The saboteur examines the information that goes through the information interchange path, altering it and generating faulty data, modification of the evaluation hardware is minimized by using saboteurs in the communication between elements. The sniffer can display the data that passes over a network, it can be configured to handle three different protocols UART, CAN or TCP/IP.
Revista:
EUROPEAN TRANSPORT RESEARCH REVIEW
ISSN:
1867-0717
Año:
2015
Vol.:
7
N°:
3
Págs.:
24
Purpose This article focuses on a novel Advanced Train LocAtion Simulator (ATLAS) for on-board railway location using wireless communication technologies, such as satellite navigation and location based systems. ATLAS allows the creation of multiple simulation environments providing a versatile tool for testing and assessing new train location services. This enhancement reduces the number of tests performed in real scenarios and trains, reducing the cost and development time of new location systems as well as assessing the performance level for given tracks. Methods The simulation platform is based on modular blocks, where each block can be replaced or improved. The platform uses Monte Carlo Simulation to generate results with statistical significance. This implementation allows the modification of the development platform to cover multiple requirements, such as, ranging errors in the input parameters or including other positioning technologies. In this paper, the generated input parameter errors have been taken from the results of the field tests realized by the 3GPP ensuring the validity of the used parameter errors. However, these could be easily adapted by the user to particular characterized environments. Results Case studies for the validation of ATLAS will be also introduced, including preliminary results related to the use of Global System for Mobile communications in Railway (GSM-R) and Universal Mobile Telecommunications System (UMTS) technologies for positioning. The validation stage provides a way to test the platform functionalities and verify its flexibility. Conclusions The versatility of the platform to perform simulations using same configuration parameters for different case studies can be highlighted. Furthermore, first conclusions are drawn from the obtained results. The characterization of the infrastructure for the simulation and the performance improvement of the location systems in the tunnels (e.g., by including Inertial Measurement Unit (IMU)) are necessary to achieve accuracy levels that can be valid for ETCS level 3.
Revista:
IEEE GEOSCIENCE AND REMOTE SENSING LETTERS
ISSN:
1545-598X
Año:
2012
Vol.:
9
N°:
1
Págs.:
47 - 51
Forward-scattering radars (FSRs) acquire great interest when low radar cross section (RCS) targets are willing to be detected. This type of radar provides a countermeasure to stealth technology because, here, the targets' RCS depends only on the size and the shape of their silhouette. Passive radars use transmitters of opportunity as signal source, and they are therefore attractive too, due to their inherit low cost. The advantage of considering Global Navigation Satellite System (GNSS) satellites as transmitters of opportunity is the high availability that these satellites offer. Anywhere on earth, around eight Global Positioning System (GPS) satellites are continuously in view. Due to the large number of new GNSS satellites becoming operational in the near future (American GPS, Russian GLONASS, European Galileo system, and Chinese COMPASS), more than 30 satellites are expected to be constantly in view. This provides an optimum scenario for implementation of a GNSS-FSR system. In this paper, experimental results of a GPS-FSR at different target-receiver scenarios near Nuremberg Airport are analyzed. Disturbances on the signals due to diffraction effects, which take place as the targets cross the receiver-satellite baselines, are discussed and evaluated. For these experiments, a hemispherical antenna has been used, which provides promising results for a future GNSS-FSR implementation.
Revista:
MICROWAVE AND OPTICAL TECHNOLOGY LETTERS
ISSN:
0895-2477
Año:
2011
Vol.:
53
N°:
12
Págs.:
2742 - 2746
Transmitting antenna in a Railway Spot Signalling System needs to be optimized in order to ensure data transfer reliability and minimize the required power. This paper analyses the improvement of the HF transmitting antenna taking into account the size of the receiving antenna, the presence of metallic objects and the misalignment between transmitting and receiving antennas. A novel HF transmitting antenna structure is proposed and verified to improve the read range.
