Imperial College London

DrArnabMajumdar

Faculty of EngineeringDepartment of Civil and Environmental Engineering

Reader in Transport Risk Management
 
 
 
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Contact

 

+44 (0)20 7594 6037a.majumdar

 
 
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Assistant

 

Mrs Maya Mistry +44 (0)20 7594 6100

 
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Location

 

604Skempton BuildingSouth Kensington Campus

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Summary

 

Publications

Publication Type
Year
to

120 results found

Yang L, Majumdar A, van Dam KH, Zhang Let al., 2021, Theories and practices for reconciling transport infrastructure, public space, and people – A review, Proceedings of the Institution of Civil Engineers - Municipal Engineer, Pages: 1-43, ISSN: 0965-0903

Journal article

Bateman G, Majumdar A, 2020, Characteristics of emergency evacuations in airport terminal buildings: A new event database, Safety Science, Vol: 130, Pages: 104897-104897, ISSN: 0925-7535

Emergency evacuations are typically employed in airport terminal buildings to protect occupants against harmful events such as fires and security incidents. Despite the importance of ensuring the effectiveness of planned for evacuation procedures, little research has been conducted to obtain a better understanding of these events, largely due to a lack of data. This paper describes how a new database containing details of airport terminal building evacuation events (ATBEE) was created, and utilised to explore the characteristics of these events. Online news articles were used as the main source material to populate the database with events. The completed database was subjected to a data quality assessment procedure, and a new quantitative index was developed to assess the reliability of the news articles utilised as source material. The database currently contains situational and etiological details of 235 evacuation events that occurred during the period January 2016 to December 2017. Analysis of the database contents determined the majority of evacuation events recorded occurred in North America and Europe, and the main cause of these events were security and terrorism related incidents, such as the identification of suspicious items. Statistical testing indicated an association exists between the geographical location of the recorded evacuations and the cause of an evacuation, and also the evacuation’s cause and the total evacuation time. A significant correlation was furthermore found between the number of evacuation events occurring at an airport, and the size of the airport.

Journal article

Psyllou E, Majumdar A, 2020, The Analysis of Airspace Infringements Over Complex Airspace in Europe and the United States of America, Journal of Navigation, Vol: 73, Pages: 1036-1051, ISSN: 0373-4633

<jats:p>The increase in the number of commercial flights highlights the need for air traffic to follow air procedures. Unfortunately, general aviation aircraft used for recreational purposes keep entering controlled and restricted airspace without obtaining permission from air traffic services. Given the safety and operational problems this could potentially cause, this paper examines the underlying reasons for these incidents occurring. In particular, it analyses airspace infringements between 2008 and 2017 involving general aviation flights that were recorded in airspace in which a large number of commercial flights also fly in Europe and America. The reports were analysed based on an initial assessment of their quality. Information was latent in the narrative and subsequently both qualitative (content analysis) and quantitative methods (descriptive statistics) of analysis were used. The analysis revealed that airspace infringements were related to the pilot's flight planning, that is, flight-route choice, navigation skills and communication, in addition to requirement to adhere to airspace procedure. The findings could be used by national authorities and flying clubs to promote safe flying in these regions.</jats:p>

Journal article

Yan F, Zhang S, Majumdar A, Tang T, Ma Jet al., 2020, A Failure Mapping and Genealogical Research on Metro Operational Incidents, IEEE Transactions on Intelligent Transportation Systems, Vol: 21, Pages: 3551-3560, ISSN: 1524-9050

Journal article

Ochieng W, Nascimento F, Majumdar A, 2020, Predictive Safety Through Survey Interviewing - Developing a Task-Based Hazard Identification Survey Process in Offshore Helicopter Operations, Advances in Human Aspects of Transportation Proceedings of the AHFE 2020 Virtual Conference on Human Aspects of Transportation, July 16-20, 2020, USA, Editors: Stenton, Publisher: Springer Nature, ISBN: 9783030509439

Offshore helicopters play a vital role in energy production worldwide and must be operated safely. Safety is underpinned by hazard identification, which aspires to be predictive and remain operationally relevant. A process to elicit pilots’ operational hazard knowledge in a predictive manner is currently absent. This paper redresses this by developing a Task-Based Hazard Identification Survey Process which, through Talk-Through interviewing, collects data from a statistically representative sample of pilots based in specified regions. A factual and exhaustive hazards’ template is formed, to which various statistical methods are applied. Subjected to multiple validation and reliability checks, the process delivers on the aspiration to be predictive on safety.

Book chapter

Ochieng W, Nascimento F, Majumdar A, 2020, redictive Safety Through Survey Interviewing - Developing a Task-Based Hazard Identification Survey Process in Offshore Helicopter Operations, Advances in Human Aspects of Transportation Proceedings of the AHFE 2020 Virtual Conference on Human Aspects of Transportation, July 16-20, 2020, USA, Editors: Stanton, Publisher: Springer Nature, ISBN: 9783030509439

This book discusses the latest advances in the research and development, design, operation, and analysis of transportation systems and their corresponding infrastructures.

Book chapter

Long F, Bateman G, Majumdar A, 2020, The impact of fire and rescue service first responders on participant behaviour during chemical, biological, radiological and nuclear (CBRN)/Hazmat incidents, International Journal of Emergency Services, Vol: 9, Pages: 283-298, ISSN: 2047-0894

<jats:sec><jats:title content-type="abstract-subheading">Purpose</jats:title><jats:p>Decontamination following chemical, biological, radiological and nuclear (CBRN)/Hazmat incidents is a critical activity carried out in order to mitigate and contain the risk posed by any hazardous materials involved. Human behaviour plays a crucial role in such incidents, as casualties will have little understanding of the situation they find themselves in, leading to uncertainty in what actions to take. This will result in very difficult circumstances within which first responders must operate. However, the importance of human behaviour appears to be a fundamental element being missed in the preparation, training and planning assumptions being made by emergency services and planners in preparation for these events.</jats:p></jats:sec><jats:sec><jats:title content-type="abstract-subheading">Design/methodology/approach</jats:title><jats:p>This paper looks to understand the scope of this omission by reviewing relevant literature on the subject and engaging with Fire and Rescue Service personnel and managers in the UK. This study utilised semi-structured interviews with 10 Fire and Rescue Service Mass Decontamination Operatives, four Fire and Rescue Service Hazardous Material Advisers and three Fire and Rescue Service Strategic Officers participating. These interviews were then analysed using a thematic framework to identified key themes from the research which were then validated using two independent researchers to provide an inter-rater reliability measure. Finally, a follow-up validation questionnaire was also developed to test the validity of the themes identified and this was completed by another with 36 Fire and Rescue Service Mass Decontamination Operatives.</jats:p></jats:sec><jats:sec><jats:title content-type="abstract-subheading">Findings</jats:title><ja

Journal article

Teoh R, Schumann U, Majumdar A, Stettler MEJet al., 2020, Mitigating the climate forcing of aircraft contrails by small-scale diversions and technology adoption, Environmental Science and Technology (Washington), Vol: 54, Pages: 2941-2950, ISSN: 0013-936X

The climate forcing of contrails and induced-cirrus cloudiness is thought to be comparable to the cumulative impacts of aviation CO2 emissions. This paper estimates the impact of aviation contrails on climate forcing for flight track data in Japanese airspace and propagates uncertainties arising from meteorology and aircraft black carbon (BC) particle number emissions. Uncertainties in the contrail age, coverage, optical properties, radiative forcing, and energy forcing (EF) from individual flights can be 2 orders of magnitude larger than the fleet-average values. Only 2.2% [2.0, 2.5%] of flights contribute to 80% of the contrail EF in this region. A small-scale strategy of selectively diverting 1.7% of the fleet could reduce the contrail EF by up to 59.3% [52.4, 65.6%], with only a 0.014% [0.010, 0.017%] increase in total fuel consumption and CO2 emissions. A low-risk strategy of diverting flights only if there is no fuel penalty, thereby avoiding additional long-lived CO2 emissions, would reduce contrail EF by 20.0% [17.4, 23.0%]. In the longer term, widespread use of new engine combustor technology, which reduces BC particle emissions, could achieve a 68.8% [45.2, 82.1%] reduction in the contrail EF. A combination of both interventions could reduce the contrail EF by 91.8% [88.6, 95.8%].

Journal article

Yang L, van Dam KH, Majumdar A, Anvari B, Ochieng WY, Zhang Let al., 2019, Integrated design of transport infrastructure and public spaces considering human behavior: A review of state-of-the-art methods and tools, FRONTIERS OF ARCHITECTURAL RESEARCH, Vol: 8, Pages: 429-453, ISSN: 2095-2635

Journal article

Majumdar A, Bateman G, 2019, “A Systems Engineering Approach to Analysing Emergency Evacuation Management in Large, Complex, Public Occupancy Buildings,”, Interflam 2019

Conference paper

Teoh R, Stettler MEJ, Majumdar A, Schumann U, Graves B, Boies AMet al., 2019, A methodology to relate black carbon particle number and mass emissions, Journal of Aerosol Science, Vol: 132, Pages: 44-59, ISSN: 0021-8502

Black carbon (BC) particle number (PN) emissions from various sources contribute to the deterioration of air quality, adverse health effects, and anthropogenic climate change. This paper critically reviews different fractal aggregate theories to develop a new methodology that relates BC PN and mass concentrations (or emissions factors). The new methodology, named as the fractal aggregate (FA) model is validated with measurements from three different BC emission sources: an internal combustion engine, a soot generator, and two aircraft gas turbine engines at ground and cruise conditions. Validation results of the FA model show that R 2 values range from 0.44 to 0.95, while the Normalised Mean Bias is between −27.7% and +26.6%. The model estimates for aircraft gas turbines represent a significant improvement compared to previous methodologies used to estimate aviation BC PN emissions, which relied on simplified assumptions. Uncertainty and sensitivity analyses show that the FA model estimates have an asymmetrical uncertainty bound (−54%,+103%) at a 95% confidence interval for aircraft gas turbine engines and are most sensitive to uncertainties in the geometric standard deviation of the BC particle size distribution. Given the improved performance in estimating BC PN emissions from various sources, we recommend the implementation of the FA model in future health and climate assessments, where the impacts of PN are significant.

Journal article

Kyriakidis M, Simanjuntak S, Singh S, Majumdar Aet al., 2019, The indirect costs assessment of railway incidents and their relationship to human error - The case of Signals Passed at Danger, JOURNAL OF RAIL TRANSPORT PLANNING & MANAGEMENT, Vol: 9, Pages: 34-45, ISSN: 2210-9706

Journal article

Psyllou E, Majumdar A, 2019, How Do General Aviation Pilots Choose Their Route When Flying in Complex Airspace?, The International Journal of Aerospace Psychology, Vol: 29, Pages: 17-27, ISSN: 2472-1840

Journal article

Koudis GS, Hu SJ, Majumdar A, Ochieng WY, Stettler MEJet al., 2018, The impact of single engine taxiing on aircraft fuel consumption and pollutant emissions, Aeronautical Journal, Vol: 122, Pages: 1967-1984, ISSN: 0001-9240

Optimisation of aircraft ground operations to reduce airport emissions can reduce resultant local air quality impacts. Single engine taxiing (SET), where only half of the installed number of engines are used for the majority of the taxi duration, offers the opportunity to reduce fuel consumption, and emissions of NOX, CO and HC. Using 3510 flight data records, this paper develops a model for SET operations and presents a case study of London Heathrow, where we show that SET is regularly implemented during taxi-in. The model predicts fuel consumption and pollutant emissions with greater accuracy than previous studies that used simplistic assumptions. Without SET during taxi-in, fuel consumption and pollutant emissions would increase by up to 50%. Reducing the time before SET is initiated to the 25th percentile of recorded values would reduce fuel consumption and pollutant emissions by 7–14%, respectively, relative to current operations. Future research should investigate the practicalities of reducing the time before SET initialisation so that additional benefits of reduced fuel loadings, which would decrease fuel consumption across the whole flight, can be achieved.

Journal article

Psyllou E, Majumdar A, Ochieng W, 2018, A Review of Navigation Involving General Aviation Pilots Flying under Visual Flight Rules, JOURNAL OF NAVIGATION, Vol: 71, Pages: 1130-1142, ISSN: 0373-4633

Journal article

Sidiropoulos S, Majumdar A, Han K, 2018, A framework for the optimization of terminal airspace operations in Multi-Airport Systems, Transportation Research Part B: Methodological: an international journal, Vol: 110, Pages: 160-187, ISSN: 0191-2615

Major cities like London, New York, and Tokyo are served by several airports, effectively creating a Multi-Airport System (MAS), or Metroplex. The operations of individual Metroplex airports are highly interdependent, rendering their efficient management rather difficult. This paper proposes a framework for the design of dynamic arrival and departure routes in MAS Terminal Maneuvering Areas, which fundamentally changes the operation in MAS airspaces for much improved efficiency when compared to the current situation. The framework consists of three components. The first presents a new procedure for characterizing dynamic arrival and departure routes based on the spatio-temporal distributions of flights. The second component is a novel Analytic Hierarchy Process (AHP) model for the prioritization of the dynamic routes, which takes into account a set of quantitative and qualitative attributes important for MAS operations. The third component is a priority-based method for the positioning of terminal waypoints as well as the design of three-dimensional, conflict-free terminal routes. Such a method accounts for the AHP-derived priorities while satisfying the minimal separation and aircraft maneuverability constraints. The developed framework is applied to a case study of the New York Metroplex, using aircraft trajectories during a heavy traffic period on typical day of operation in the New York Terminal Control Area in November 2011. The proposed framework is quantitatively assessed using the AirTOp fast-time simulation model. The results suggest significant improvements of the new design over the existing one, as measured by several key performance indicators such as travel distance, travel time, fuel burn, and controller workload. The operational feasibility of the framework is further validated qualitatively by subject matter experts from the Port Authority of New York and New Jersey, the operator of the New York Metroplex.

Journal article

Majumdar A, Singh S, Kyriakidis M, 2018, Incorporating Human Reliability Analysis to enhance Maintenance Audits: The Case of Rail Bogie Maintenance, International Journal of Prognostics and Health Management, Vol: 8, ISSN: 2153-2648

Human error occurring during maintenance activities can reduce the safety and availability of equipments significantly. Identification of potential human errors, the cause of such errors and prediction the associate probability are important stages in order to manage the human errors. This paper investigates the probability of human error during maintenance of railway bogie. The case study examines technicians performing maintenance on the disc brake assembly unit, wheel set and bogie frame under various error producing conditions in a railway maintenance workshop in Luleå, Sweden. It implements Human Error Assessment and Reduction Technique (HEART) to determine the probability of human error occurring during each maintenance task, and applies fault tree analysis. The probability of the technician committing an error during maintenance of the disc brake assembly, wheel set and bogie frame is found to be 0.20, 0.039 and 0.021 respectively, with the human error probability for the entire bogie 0.24. Time pressures, ability to detect and perceive problems, over-riding information, the need to make decisions and mismatch between the operator and designer’s model turn out to be major contributors to human error. These findings can help maintenance management understand conditions and serve as an input to modify policies and guidelines for railway maintenance tasks.

Journal article

Kyriakidis M, Majumdar A, Ochieng WY, 2017, The human performance railway operational index—a novel approach to assess human performance for railway operations, Reliability Engineering and System Safety, Vol: 170, Pages: 226-243, ISSN: 0951-8320

Human error and degraded human performance are associated with more than 80% of all railway accidents worldwide. Research on human performance and human reliability has highlighted the importance of the contextual factors associated with human errors, known as performance shaping factors (PSFs). A major shortcomings of current Human Reliability Analysis techniques, which employ qualitative and quantitative methods for assessing the human contribution to risk, lies with their little capability to model the dependencies among PSFs and to quantify their impact on human performance. This paper presents a novel approach to assess human performance accounting for the dependencies among the relevant PSFs, referred to as Human Performance Railway Operational Index (HuPeROI). The HuPeROI is developed on the integration of the Analytic Network Process and Success Likelihood Index Methodology, using the insights of 52 front-line, managerial and human factors railway personnel, and was demonstrated in three different types of railway operations: regional, high-speed and underground. Findings show that the HuPeROI can be efficiently used to assess operators’ performance as function of the quality of the relevant R-PSFs. Regulatory bodies and other stakeholders can implement the framework within their safety management systems to improve safety of railway operations.

Journal article

Costa Teixeira Santos PL, Antunes Monteiro PA, Studic M, Majumdar Aet al., 2017, A methodology used for the development of an Air Traffic Management functional system architecture, Reliability Engineering and System Safety, Vol: 165, Pages: 445-457, ISSN: 0951-8320

The Air Traffic Management (ATM) system provides a safe, economical, efficient, dynamic and integrated management of air traffic and airspace through the collaborative integration of humans, infrastructure (technology and facilities) and organisations. At present, it is widely accepted that the ATM system is one of the leading complex socio-technical systems in terms safety performance. To maintain this reputation, safety management of the ATM system needs to be able to cope with not only rising travel demand, but also the increased automation, the tighter coupling between its component elements and greater complexity of the ATM system itself. As a way of ensuring this, in Europe the European Union Regulation 1035/2011 requires the Air Navigation Service Providers (ANSPs) responsible for the provision of ATM, to describe and model their systems by accounting for the functional interactions between the equipment, procedures and human resources of the ATM system. However, despite the number of available models of the ATM system, none of them meets this requirement. Typically the existing models focus on the technical functions and describe the system usage via operational scenarios. Therefore this paper proposes a novel methodology used for the development of a functional system architecture − Model of ATM Reality In Action (MARIA) − with the aim to provide a sound base for system analysis, including safety, namely by describing the whole system and the interdependencies between its functions. By overcoming the limitations of the existing models MARIA has the potential to improve understanding of the ATM services safety, system resilience and meet the requirements of the Regulation 1035/2011. Lastly, the methodology applied in the ATM domain presented in this paper is equally transferable to systemic modelling of other complex socio-technical systems.

Journal article

Koudis GS, Hu SJ, North RJ, Majumdar A, Stettler MEJet al., 2017, The impact of aircraft takeoff thrust setting on NO<inf>X</inf> emissions, Journal of Air Transport Management, Vol: 65, Pages: 191-197, ISSN: 0969-6997

Reduced thrust takeoff has the potential to reduce aircraft-related NO X emissions at airports, however this remains to be investigated using flight data. This paper analyses the effect of takeoff roll thrust setting variability on the magnitude and spatial distribution of NO X emissions using high-resolution data records for 497 Airbus A319 activities at London Heathrow. Thrust setting varies between 67 and 97% of maximum, and aircraft operating in the bottom 10th percentile emit on average 514 g less NO X per takeoff roll (32% reduction) than the top 10th percentile, however this is dependent on takeoff roll duration. Spatial analysis suggests that peak NO X emissions, corresponding to the start of the takeoff roll, can be reduced by up to 25% by adopting reduced thrust takeoff activities. Furthermore, the length of the emission source also decreases. Consequently, the use of reduced thrust takeoff may enable improved local air quality at airports.

Journal article

Ali BS, Ochieng WY, Majumdar A, 2017, ADS-B: Probabilistic Safety Assessment, JOURNAL OF NAVIGATION, Vol: 70, Pages: 887-906, ISSN: 0373-4633

Journal article

Koudis GS, Hu J, Majumdar A, Jones R, Stettler MEJet al., 2017, Airport emissions reductions from reduced thrust takeoff operations, Transportation Research Part D: Transport and Environment, Vol: 52, Pages: 15-28, ISSN: 1361-9209

Given forecast aviation growth, many airports are predicted to reach capacity and require expansion. However, pressure to meet air quality regulations emphasises the importance of efficient ground-level aircraft activities to facilitate growth. Operational strategies such as reducing engine thrust setting at takeoff can reduce fuel consumption and pollutant emissions; however, quantification of the benefits and consistency of its use have been limited by data restrictions. Using 3,336 high-resolution flight data records, this paper analyses the impact of reduced thrust takeoff at London Heathrow. Results indicate that using reduced thrust takeoff reduces fuel consumption, nitrogen oxides (NOX) and black carbon (BC) emissions by 1.0-23.2%, 10.7-47.7%, and 49.0-71.7% respectively, depending on aircraft-engine combinations relative to 100% thrust takeoff. Variability in thrust settings for the same aircraft-engine combination and dependence on takeoff weight (TOW) is quantified. Consequently, aircraft-engine specific optimum takeoff thrust settings that minimise fuel consumption and pollutant emissions for different aircraft TOWs are presented. Further reductions of 1.9%, 5.8% and 6.5% for fuel consumption, NOX and BC emissions could be achieved, equating to reductions of approximately 0.4%, 3.5% and 3.3% in total ground level fuel consumption, NOX and BC emissions. These results quantify the contribution that reduced thrust operations offer towards achieving industry environmental targets and air quality compliance, and imply that the current implementation of reduced thrust takeoff at Heathrow is near optimal, considering operational and safety constraints.

Journal article

Sidiropoulos S, Han K, Majumdar A, Ochieng Wet al., 2017, Robust identification of air traffic flow patterns in Metroplex terminal areas under demand uncertainty, Transportation Research Part C: Emerging Technologies, Vol: 75, Pages: 212-227, ISSN: 0968-090X

Multi-Airport Systems (MAS), or Metroplexes, serve air traffic demand in cities with two or more airports. Due to the spatial proximity and operational interdependency of the airports, Metroplex airspaces are characterized by high complexity, and current system structures fail to provide satisfactory utilization of the available airspace resources. In order to support system-level design and management towards increased operational efficiency in such systems, an accurate depiction of major demand patterns is a prerequisite. This paper proposes a framework for the robust identification of significant air traffic flow patterns in Metroplex systems, which is aligned with the dynamic route service policy for the effective management of Metroplex operations. We first characterize deterministic demand through a spatio-temporal clustering algorithm that takes into account changes in the traffic flows over the planning horizon. Then, in order to handle uncertainties in the demand, a Distributionally Robust Optimization (DRO) approach is proposed, which takes into account demand variations and prediction errors in a robust way to ensure the reliability of the demand identification. The DRO-based approach is applied on pre-tactical (i.e. one-day planning) as well as operational levels (i.e. 2-h rolling horizon). The framework is applied to Time Based Flow Management (TBFM) data from the New York Metroplex. The framework and results are validated by Subject Matter Experts (SMEs).

Journal article

Studic M, Majumdar A, Schuster W, Ochieng WYet al., 2017, A systemic modelling of ground handling services using the functional resonance analysis method, Transportation Research Part C: Emerging Technologies, Vol: 74, Pages: 245-260, ISSN: 0968-090X

In contrast to air transport safety, safety in ground handling is not concerned only with aircraft accidents but also the Occupational Health and Safety of the employees who work at airport aprons. Ground handling safety costs the aviation industry tens of billions USD every year which raises the questions about the effectiveness of linear safety risk management of Ground Handling Services (GHS). This paper uses the state-of-the-art safety theory to justify and highlight the need for a systemic approach to safety risk management of GHS on the apron. A hybrid Total Apron Safety Management (TASM) framework, based on the combination of Functional Resonance Analysis Method (FRAM), Grounded Theory, Template Analysis and Goals-Means Task Analysis (GMTA) was developed to support systemic safety modelling of GHS. The data that underpins the TASM framework includes extensive literature review, 15 observations, 43 interviews and expert judgement across five international airports. While the TASM framework can be applied in retrospective, prospective and system design analysis to improve both the safety management and the efficiency of apron operations, this paper showcases only one of its application on a case study of a historical safety occurrence. The results of the investigation carried out in this paper clearly demonstrate the benefits of the systemic as opposed to the existing linear approaches to retrospective safety analyses and the suitability of the TASM framework for occurrence analysis and prevention.

Journal article

Pien KC, Han K, Majumdar A, 2016, A linear programming approach for system-optimal dynamic traffic assignment in the European Air Traffic Network, Transportation Research Board 96th Annual Meeting

Conference paper

Anvari B, Majumdar A, Ochieng W, 2016, Mixed traffic modelling involving pedestrian dynamics for integrated street designs: A review, PED2016: 8th International Conference on Pedestrian and Evacuation Dynamics

Conference paper

Sidiropoulos S, Han K, Majumdar A, Ochieng Wet al., 2016, Identifying significant traffic flow patterns in Multi-Airport Systems Terminal Manoeuvring Areas under uncertainty, 16th AIAA Aviation Technology, Integration, and Operations Conference

Conference paper

Nascimento FAC, Majumdar A, Ochieng WY, Schuster W, Studic Met al., 2016, Fundamentals of safety management: The Offshore Helicopter Transportation System Model, Safety Science, Vol: 85, Pages: 194-204, ISSN: 0925-7535

Journal article

Damy S, Majumdar A, Ochieng WY, 2016, GNSS-based High Accuracy Positioning for Railway Applications, 47th Annual Precise Time and Time Interval Systems and Applications Meeting (PTTI) / International Technical Meeting of the-Institute-of-Navigation, Publisher: Institute of Navigation, Pages: 1003-1014

The railway industry is facing a global increase in travel and freight demand, which requires extra capacity. Providing such capacity is limited by the current positioning systems used for railway traffic management. The past decade has seen a growing interest in GNSSbased positioning solutions for railway applications due to their global coverage, low cost and interoperability with existing systems. However, the railway operational environment presents a number of challenges to GNSS due to track side buildings, stations and tunnels which attenuate or block signals and generate multipath. This paper reviews the wide range of railway applications that can benefit from a GNSS-based enhanced positioning function, along with the existing requirements. It reviews the different positioning techniques that can be used and the different error sources the system has to deal with, including multipath. Finally it compares the effect of different multipath mitigation weighting techniques including elevation weighting, C/N0 weighting, residualbased weighting and multipath-based weighting. A novel adaptive weighting method based on the railway track geometry is introduced also and is compared to the current methods.

Conference paper

Nascimento FAC, Majumdar A, Ochieng WY, Schuster Wet al., 2015, Nighttime offshore helicopter operations: a survey of risk levels per phase of flight, flying recency requirement and visual approach technique, AERONAUTICAL JOURNAL, Vol: 119, Pages: 1475-1498, ISSN: 0001-9240

Journal article

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