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Toutes les publications de l'ENAC en direct.
All ENAC publications.

[tel-01528481] Modeling and monitoring of new GNSS signal distortions in the context of civil aviation

Publications ENAC - Lundi, 29 mai 2017 - 16:39:07
Global Navigation Satellite Systems (GNSS) is used nowadays in various fields for navigation and positioning including safety-of-life applications. Among these applications is civil aviation that requires a very high quality of service for the most demanding phases of flight. The quality of the GNSS service is typically based on four criteria (integrity, accuracy, availability and continuity), that have to meet International Civil Aviation Organization (ICAO) requirements. To meet these requirements any source of potential service degradations has to be accounted for. One such example is GNSS signal distortions due to the satellite payload which can manifest in two ways...

[hal-01525779] Signal Quality Monitoring Design for Galileo E5a and Galileo E1C signals

Publications ENAC - Lundi, 29 mai 2017 - 16:18:32
Galileo E1C, the pilot component of the E1 Open Service signal (CBOC(6,1,1/11) modulation), Galileo E5a and GPS L5 (BPSK(10) modulation) are signals that will be used by civil aviation receivers for pseudorange computation. To meet stringent requirements defined for civil aviation GNSS receivers, the characterization of distortions which could affect a GNSS signal in a hazardous way is required. In particular, expected signal distortions generated at payload level are described by Threat Models (TMs). Distortions incorporated in the TM are also called Evil WaveForm (EWF). These TMs, and their associated parameter ranges, referred to as Threat Space (TS), are powerful and...

[hal-01526879] Convergence of an estimator of the Wasserstein distance between two continuous probability distributions

Publications ENAC - Jeudi, 25 mai 2017 - 03:09:44
This article is dedicated to the estimation of Wasserstein distances and Wasserstein costs between two distinct continuous distributions $F$ and $G$ on $\mathbb R$. The estimator is based on the order statistics of (possibly dependent) samples of $F$ resp. $G$. We prove the consistency and the asymptotic normality of our estimators.

[hal-01449963] On a three dimensional vision based collision avoidance model

Publications ENAC - Mercredi, 24 mai 2017 - 03:09:14
This paper presents a three dimensional collision avoidance approach for aerial vehicles inspired by coordinated behaviors in biological groups. The proposed strategy aims to enable a group of vehicles to converge to a common destination point avoiding collisions with each other and with moving obstacles in their environment. The interaction rules lead the agents to adapt their velocity vectors through a modification of the relative bearing angle and the relative elevation. Moreover the model satisfies the limited field of view constraints resulting from individual perception sensitivity. From the proposed individual based model, a mean-field kinetic model is derived....

[hal-01521890] Knowledge Discovery in Graphs Through Vertex Separation

Publications ENAC - Vendredi, 19 mai 2017 - 17:38:04
This paper presents our ongoing work on the Vertex Separator Problem (VSP), and its application to knowledge discovery in graphs representing real data. The classic VSP is modeled as an integer linear program. We propose several variants to adapt this model to graphs with various properties. To evaluate the relevance of our approach on real data, we created two graphs of different size from the IMDb database. The model was applied to the separation of these graphs. The results demonstrate how the model is able to semantically separate graphs into clusters.

[hal-01512448] Signal Quality Monitoring for New GNSS Signals

Publications ENAC - Vendredi, 19 mai 2017 - 03:00:53
In the context of GNSS signals and associated augmentation systems modernization, new modulations are envisaged. More precisely Galileo E1C, the pilot component of the E1 Open Service signal (CBOC(6,1,1/11) modulation), Galileo E5a and GPS L5 (BPSK(10) modulation) are signals that will be used by civil aviation airborne receivers for pseudorange computation. To meet stringent requirements defined for civil aviation GNSS receivers, the characterization of distortions which could affect a GNSS signal in a hazardous way is required. In particular, expected signal distortions generated at payload level are described by Threat Models (TM). Distortions incorporate in the TM...

[hal-01522246] System simulation of a fleet of drones to probe cumulus clouds

Publications ENAC - Mercredi, 17 mai 2017 - 03:07:50
Simulation plays an essential role in the development of complex systems. This paper reports on the development of a simulation infrastructure for a fleet of UAVs conceived to probe clouds, using an adaptive sampling scheme that calls for cloud mapping and trajectory planning. The mission is presented, the global approach to solve it and the ensemble of required processes are sketched. An overall simulation architecture is then depicted, and the details of its development using the Robot Operating System (ROS) are presented.

[hal-01522250] Adaptive sampling of cumulus clouds with UAVs

Publications ENAC - Mercredi, 17 mai 2017 - 03:07:50
This paper presents an approach to guide a fleet of Unmanned Aerial Vehicles to actively gather data in low-altitude cumulus clouds with the aim of mapping atmospheric variables. Building on-line maps based on very sparse local measurements is the first challenge to overcome, for which an approach based on Gaussian Processes is proposed. A particular attention is given to the on-line hyperparameters optimization , since atmospheric phenomena are strongly dynamical processes. The obtained local map is then exploited by a trajectory planner based on a stochastic optimization algorithm. The goal is to generate feasible trajectories which exploit air flows to perform energy-...

[hal-01522067] Cognitive Maps Exploration trough Kernel Density Estimation

Publications ENAC - Mardi, 16 mai 2017 - 17:54:40
Currently approximately 860,000 people are affected by Alzheimer’s disease in France. This is why the study of Alzheimer’s disease has been identified as a major societal challenge. In the PAQUID cohort study, subjects performed a lexical evocation task by saying the maximum number of city names within 3 minutes. This task is directly related to the concept of cognitive map. The analysis of the list created by this task provides a unique opportunity to study the spatial mental representation of geographical space for elderly people before and after developing the dementia. We visualized graphs of this list by connecting cited city with a line. Since these graphs become...

[hal-01521988] Advanced decision aids for Air Traffic Controllers : Understanding different working methods from a cognitive point of view

Publications ENAC - Mardi, 16 mai 2017 - 16:30:20
This paper presents some experimental results about a major air traffic controllers' cognitive process while working with a new decision support system called Erato. This project is developed by the French Research Center for Civil Aviation (CENA). We are aiming at getting a good level of understanding of how controllers use the main functions of the system, so as to ensure relevant improvements in the future. Results are organized in two sections. Firstly, we present some results about unexpected use of the system and of various working methods with Erato. Secondly, our objective is to show that this use of the system can be explained in part by cognitive processes that...
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