269,299 research outputs found

    Spaceways: Airspace in Outer Space

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    Forecasted future demand in space travel is driving the need for the development of space traffic management. Currently, orbital space traffic is mostly unregulated with internationally agreed upon best practices and self-interest driving space operators to avoid collisions with other spacecraft. This paper explores the future of space travel by presenting a concept of creating “airspace in space” or spaceways to manage the ever growing volumes of space traffic. Spaceways are analogous to airspace for aircraft with the goal of increasing levels of safety and reducing probabilities of collision. These goals can be achieved by creating traffic rules, defining valuable orbits and minimum capabilities for spacecraft to be flying in the defined valuable orbits. The paper will discuss the creation and evolution of airspace for aircraft, provide an explanation for the need of spaceways and discuss a specific concept for defined spaceways in outer space, including some of the disadvantages for creating spaceways. Additionally, airspace is more than managing the flow of air traffic but also a means of nation-states defining the boundaries of their sovereignty. The current legal framework regarding sovereignty in space, arguments for and against a delimitation line between airspace and outer space and the need for international cooperation to define the spaceways will also be discussed. Lastly, further inquiry into liability implications due to the definition of spaceways and potential organizations to create and control the spaceways will be discussed. Keywords: Space Traffic Management, STM, Spaceways, Airspace, Orbital, Debris, Space Law, Liabilit

    Organizational Psychology and Safety Culture in Air Traffic Control : Concerning Organizational Climate, Situational Leadership and Psychosocial Work Environment

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    The air traffic control industry in Europe is under mounting pressure due to increasing air traffic and inefficient routines caused by a fragmented air space. In order to handle the demands the European Commission has launched a program entitled the Single European Sky initiative which seeks to promote a more efficient way of handling the air traffic over Europe. A reorganization of air traffic management will be introduced during this process and air traffic control centers in Europe will be merged. New tech-nology will further be implemented and the air space will be rationalized. In this context the Swedish air traffic control provider is an interesting case since an adaptation to increasing air traffic and the Single European Sky initiative has already begun through the introduction of new organizational structures and new technology. As psycho-organizational aspects can be identified as affecting safety out-comes in high risk organizations with highly reliable operations, the overall aim of the research presented in this thesis was to study different psycho-organizational aspects in Swedish air traffic control during times of change. The studies on which this thesis is based focused on: innovative organizational climate, examining the innovative preparedness and capacity to cope with changes in a highly regulated organizational environment; situational leader-ship, examining leadership characteristics in a high risk organization with a well developed safety culture; psychosocial work environment, examining critical psychosocial environmental factors in a high risk organization with de-manding work operations; and safety culture, examining perceptions of safety culture as well as the relationships between safety culture aspects and or-ganizational climate dimensions. All in all, five studies were conducted of which four were empirical. The empirical studies were all conducted at two air traffic control centers and an administrative air traffic services (ANS) unit which was part of the LFV Group Swedish Airports and Air Navigation Services. The three study loca-tions employed 635 air traffic controllers and other staff members. The or-ganizational climate was measured with the Creative Climate Questionnaire (CCQ) (Ekvall, 1990), the situational leadership with the Leader Effectiveness and Adaptability Description (LEAD) (Hersey & Blanchard, 1988; Holmkvist, 2000), the psychosocial work environment with the Copenhagen Psychosocial Questionnaire (COPSOQ) (Kristensen, Hannerz, Høgh & Borg, 2005), and the safety culture with the safety culture assessment questionnaire devel-oped by Ek (2006). Study I concluded that the existing empirical research concerning relation-ships between organizational climate, leadership and safety culture or safety climate is limited. Previous research supports the assumption that safety culture is related to other psycho-organizational aspects, but the knowledge base is still too limited to be conclusive. The ambiguity in defining and op-erationalizing the concepts is an additional weakness in the field. It was further assumed that the innovative organizational climate would be under-developed in air traffic control due to the strict regulatory framework which is present in this environment. The results from Study II revealed, however, that the innovative organizational climate was quite positive in spite of the rule governed work. Differences in the assessment of the inno-vative organizational climate could be identified according to work charac-teristics and work tasks but not according to organizational position. Study III concluded that the situational leadership characteristics differed according to situation. The leadership behavior was more relationship-oriented in Success and Group situations compared with Hardship and Individual situations. The leadership adaptability ? the leader's ability to adjust leader-ship style according to the situation ? was superior in Success and Individual situations than in Hardship and Group situations. Operational conditions, lead-ership structures and working tasks were, on the other hand, not associated with leadership behavior. Three aspects of the psychosocial work environment were identified as dif-ficult in air traffic control in Study IV. In an otherwise positive assessment, Sensorial demands, Freedom and Feedback were challenging aspects. These as-pects seemed to be characteristic for operative air traffic control work since the operative personnel assessed them to be statistically significantly less positive than did the administrative personnel. Organizational position was also found to be influential in the assessment of psychosocial work envi-ronmental factors since the management group made more positive as-sessments on a number of dimensions. The effect of differences in opera-tional conditions was, however, limited. The safety culture was positively assessed in the Swedish air traffic control context according to Study V. The administrative ANS unit had generally somewhat lower scores than the two operative air traffic control centers. Overall, Communication, Justness and Flexibility received slightly lower scores than the rest of the safety culture aspects. The results further demonstrated that the two organizational climate dimensions, Support for ideas and Conflicts, were positively and most frequently related to the various safety culture as-pects at the two air traffic control centers. However, few relationships were found between the safety culture and organizational climate concepts at the administrative ANS unit. Because of the limited knowledge concerning the influence of organiza-tional aspects on safety and their possible relationships with safety culture and safety climate, more research in this area is desired, especially in the field of air traffic control. Due to differences in national conditions and culture as well as local variations, studies similar to those conducted in Sweden are also needed in other European countries in order to make the transition to the Single European Sky as smooth, safe and efficient as pos-sible

    Galileo and EGNOS as an asset for UTM safety and security

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    GAUSS (Galileo-EGNOS as an Asset for UTM Safety and Security) is a H2020 project1 that aims at designing and developing high performance positioning systems for drones within the U-Space framework focusing on UAS (Unmanned Aircraft System) VLL (Very Low Level) operations. The key element within GAUSS is the integration and exploitation of Galileo and EGNOS exceptional features in terms of accuracy, integrity and security, which will be key assets for the safety of current and future drone operations. More concretely, high accuracy, authentication, precise timing (among others) are key GNSS (Global Navigation Satellite System) enablers of future integrated drone operations under UTM (UAS Traffic Management) operations, which in Europe will be deployed under U-Space [1]. The U-Space concept helps control, manage and integrate all UAS in the VLL airspace to ensure the security and efficiency of UAS operations. GAUSS will enable not only safe, timely and efficient operations but also coordination among a higher number of RPAS (Remotely Piloted Aircraft System) in the air with the appropriate levels of security, as it will improve anti-jamming and anti-spoofing capabilities through a multi-frequency and multi-constellation approach and Galileo authentication operations. The GAUSS system will be validated with two field trials in two different UTM real scenarios (in-land and sea) with the operation of a minimum of four UTM coordinated UAS from different types (fixed and rotary wing), manoeuvrability and EASA (European Aviation Safety Agency) operational categories. The outcome of the project will consist of Galileo-EGNOS based technological solutions to enhance safety and security levels in both, current UAS and future UTM operations. Increased levels of efficiency, reliability, safety, and security in UAS operations are key enabling features to foster the EU UAS regulation, market development and full acceptance by the society.Peer ReviewedPostprint (author's final draft

    Priority Management for Urban Arterials. Transferability of Techniques: Methodology and Summary.

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    This paper describes the background and methodology employed in research funded by EPSRC to assess the effect of individual traffic control measures on urban arterials, both in isolation and in combination. The aim of the project was to test the transferability of the techniques developed in a DRIVE II project, PRIMAVERA, to a range of different types of urban corridor. Measures have been classed into three broad categories: Congestion Management, Public Transport Priority and Traffic Calming. The scope of these measures is wide, some operating at a junction level whilst others have an impact over a whole corridor. Measures from these categories are applied in a sophisticated microsimulation model of a series of hypothetical networks and four urban arterial corridors: three in Leeds and one in Leicester. The effects of the application of individual and integrated measures are assessed in terms of their efficiency, environmental and safety impacts using a form of Multi-Criteria Analysis. Travel time and other monetary costs are also taken into consideration. Whilst these results are of interest to local planners in the operation of each of the arterial corridors studied, a wider insight into the operation of urban arterials can be drawn from this study leading to more efficient control of the available road space

    Priority Management for Urban Arterials. Transferability of Techniques: Humberstone/Uppingham Road.

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    This paper describes the background and methodology employed in research funded by EPSRC to assess the effect of individual traffic control measures, both in isolation and in combination upon urban arterials. The aim of the project was to test the transferability of the techniques developed in a DRIVE II project, PRIMAVERA, to a range of different types of urban corridor. The techniques concerned can be classed into three broad categories: Congestion Management, Public Transport Priority and Traffic Calming. The scope of these measures is wide, some operating at a junction level whilst others concentrate on the efficient use of road space. Measures from these areas are applied to a sophisticated microsimulation model of four urban arterial corridors: three in Leeds and one in Leicester. The effects of the application of individual and integrated measures are assessed in terms of their efficiency, environmental and safety impacts using a form of Multi-Criteria Analysis. Travel time and other monetary costs are also taken into consideration. This paper reports the results for the A47 Humberstone and Uppingham Roads which form the main arterial route to the east of Leicester

    A decomposition-based optimal control approach for aircraft conflict avoidance performed by velocity regulation

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    International audienceOne of the decisive tasks within the air traffic management is the resolution of aircraft conflict avoidance problems. To avoid conflict, aircraft have to preserve a minimal safety distance between them. In this paper, we present optimal control models and approaches based on speed regulation to perform aircraft conflict avoidance. We consider some aircraft configurations with separable trajectories, i.e., such that trajectories of aircraft pairs exhibit conflict zones which are each other separated in terms of time and/or space. We propose a decomposition of the problem in such a way to solve independently subproblems of the original one

    A simple algorithm for the estimation of road traffic space mean speeds from data available to most management centres

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    [Abstract:] The control of the evolution of road traffic streams is highly related to productivity, safety, sustainability and, even, comfort. Although, nowadays, the findings from research efforts and the development of new technologies enable accurate traffic forecasts in almost any conditions, these calculations are usually limited by the data and the equipment available. Most traffic management centres depend on the data provided, at best, by double-loop detectors. These loops supply time means over different aggregation periods, which are indiscriminately used as the bases for subsequent estimations. Since space mean speeds are those needed in most applications (note the fundamental relationship between flow and density in traffic flow theory), most current practice begins with an error. This paper introduces a simple algorithm that the allows estimation of space mean speeds from the data provided by the loops without the need for any additional financial outlay, as long as the traffic in each time interval of aggregation is stationary and its speed distribution is log-normal. Specifically, it is focused on the calculation of the variance of the speeds with regard to the time mean, thus making possible to use the relationship between time mean speeds and space mean speeds defined by Rakha (2005). The results obtained with real data show that the algorithm behaves well if the calculation conditions help fulfil the initial hypotheses. The primary difficulties arise with transient traffic and, in this case, other specific methodologies should be used. Data fusion seems promising in this regard. Nevertheless, it cannot be denied that the improvement provided by the algorithm turns out to be highly beneficial both when used alone in the case of stationarity or as a part of a fusion
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