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Heuristic search for multi‐distance measuring equipment station selection
No full textInternational audienceTo support alternative positioning, navigation and timing (A-PNT), multi-DME with better geometry than distance measuring equipment (DME)/DME can be used to improve the performance. Different from the existing station selection methods that have been proposed for DME/DME, a station selection method for multi-DME should be considered in order to prevent unnecessary emission of navigation signals because DME receivers have limited number of channels and constrained real-time processing power, and also to limit DME to GNSS L5/E5a interference. A heuristic algorithm is constructed to determine the quasi-optimal selection of DME stations based on geometrical and computational cost restrictions, which is different from a brute-force method checking all possible subsets and selecting the best one. A station selection method for multi-DME is proposed based on the heuristic search. Meanwhile, the degradation of GNSS L5/E5a signal processing that is caused by DME signals is discussed. An advanced station selection method where the DME to GNSS signal interference is taken into account is also proposed. The experimental results show that the methods based on heuristic search can effectively select the quasi-optimal subset of DME stations with less computational expense
Interactive trajectory modification and generation with FPCA
No full textInternational audienceMoving object analysis is a constantly growing field with numerous concrete applications in terms of traffic understanding, prediction and simulation. While many algorithms and analytic processes exist, there are still areas of investigation with novel trajectory analysis methods. As such, the geometric information analyses data with respect to its statistical distribution along extracted dimensions. This opens new ways of gaining a better understanding of large and complex trajectory data sets while providing flexible data manipulations. In this paper, we report our investigations with the development of an interactive methodology based on the geometric information analytic process where users can analyze trajectories sets, cluster and deform them maintaining the actual statistical properties of the investigated trajectories. As a contribution, this paper shows how Functional Data Analysis can provide novel support for trajectory analyses taking into account the statistical properties of the investigated clusters. We also provide recommendations for efficient usage of the process, considering trajectory registration, initial clustering, trajectory deformation and generation. These recommendations are illustrated with actual examples validated by a domain expert of air traffic flow analysis
A tailored Machine Learning Surrogate to improve Rotorcraft Trajectory Design
No full textInternational audienceA tailored Machine Learning Surrogate to improve Rotorcraft Trajectory Desig
Synchronisation des horaires trains-avions pour un trajet porte-à-porte plus harmonieux
No full textInternational audienceSynchronisation des horaires trains-avions pour un trajet porte-à-porte plus harmonieu
Parallel Accurate and Reproducible Summation
No full textInternational audienceFloating-point arithmetic is prone to accuracy problems due to the round-off errors. The combination of the round-off errors and of the out of order execution of arithmetic operations due to the scheduling of parallel tasks, introduces additional numerical accuracy issues. In this article, we address the problem of improving the numerical accuracy and reproducibility of summation operators. We propose two efficient parallel algorithms for summing n floating-point numbers. The first objective of our algorithms is to obtain an accurate result without increasing the linear complexity of the naive algorithm. The second objective is to improve the reproducibility of the summations compared to those computed by the naive algorithm and this regardless of the number of processors used for the computations
Ariadne: A common-sense thread for enabling provable safety in air mobility systems with unreliable components
No full textInternational audienc
Research on slot allocation for airport network in the presence of uncertainty
No full textInternational audienceIn this paper, a slot allocation model for airport network in the presence of uncertainty is proposed. The airport resource planning problem is modeled as a process from an aggregate level and an individual level for multiple days’ slot scheduling in order to consider capacity uncertainty at airports characterized by meteorological scenarios. The aggregate level uses a two-stage model to minimize the sum of displacement cost and delay cost in the worst-case scenario using Benders’ Decomposition-based algorithm. At the individual level, an integer linear programming model is developed based on the results from the aggregate level to provide specific departure slot and arrival slot for each flight. An airport network composed of 15 coordinated airports in China is studied andshows that by experimental analysis the overall optimization method is capable of providing robust and efficient solutions for slot allocation and benefits from high computational efficiency. The out performance of the two-stage optimization method from the aggregate level is also illustrated in comparison with the one-stage optimization method. Finally, recommendations for the slot allocation policy in practice are provide
Two-stage stochastic programming models for the extended aircraft arrival management problem with multiple pre-scheduling points
No full textInternational audienceExtended aircraft arrival management under uncertainty has been previously studied in the literature using two-stage stochastic optimization in the case of a single initial approach fix (IAF) and a single runway. In this paper, we propose an extension taking into account: (i) multiple IAFs feeding the landing runway, (ii) aircraft having different initial flight status (at-departure-gate or airborne) when making first-stage decisions, and (iii) a time-deviation cost function to minimize that is based on reference values depending on aircraft type and flight phase. Two problem variants are modeled according to the degree of freedom on IAF assignment to aircraft. In the first variant, IAFs are to be assigned to aircraft, as a first-stage decision. In the second variant, IAF assignment is fixed and considered as a problem input. Numerical results on realistic instances from Paris Charles-de-Gaulle airport confirm the benefit of taking into account uncertainty through two-stage stochastic programming, and through re-assignment of IAFs
Route network design in low-altitude airspace for future urban air mobility operations: A case study of urban airspace of Singapore
No full textInternational audienceThe rapid growth of the metropolis leads to the proposal of alternative solutions, including the concept of Urban Air Mobility (UAM). Automated and highly-integrated UAM networks have been proved to have great advantages to handle UAM traffic flow with intense density and complexity in the near future. This research addresses designing UAM route networks in low-altitude airspace to minimize noise impact and maximize the efficiency and safety of UAM operations. Singapore's urban airspace is selected for the case study. On the basis of the open-source data of Singapore, the UAM network is designed as a grid-based multi-layer route network that supports twoway traffic. The topology features of the route network are analyzed. To provide alternative travel options for UAM traffic flow, we search for feasible routes between Origin-Destination (OD) pairs by solving k-Shortest Path with Diversity (KSPD) problem that minimizes link costs in terms of noise impact, safety and efficiency. The resulting feasible routes can potentially reduce airspace complexity and can be used for air traffic assignment. In addition, the impact of different parameter settings for link costs on UAM services is explored
Towards the use of public networks for safety-related aeronautical communications
No full textInternational audienceAircrafts are increasingly equipped with in-flight connectivity systems, giving access to broadband communications for passengers. This paper studies whether it may be possible to use these public air-ground networks to also support aircraft safety-related aeronautical communications in the future. The benefits and other justifications are also examined, including the challenges and potential 'showstoppers'. It provides a risk and a SWOT analysis and introduces potentially suitable technical mechanisms