Archives Ouvertes HAL

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

[hal-02267447] Experimental Study of Aerosol-Cloud Interactions using a 5-hole Probe with Remotly Piloted Aircraft

Publications ENAC - Thursday, 22 August 2019 - 19:22:50
Enhancements in Remotely Piloted Aircraft Systems (RPAS) have increased their possible uses in many fields for the past two decades. For atmospheric research, ultra-light RPAS (<2.5kg) are now able to fly at altitudes greater than 3 km and even in cloud, which opens new opportunities to understand aerosol-cloud interactions. The European project BACCHUS (Impact of Biogenic versus Anthropogenic Emissions on Clouds and Climate: towards a Holistic Understanding) focuses on these specific interactions.

[hal-02269342] Drone Fleet Deployment Strategy for Large Scale Agriculture and Forestry Surveying

Publications ENAC - Thursday, 22 August 2019 - 19:17:04
Agriculture drones offer clear advantages over other monitoring methods including satellite imaging, manned scouting, and manned aircraft. However, for large scale areas, such as large forestry and agriculture mapping problems, the single drone is hard to accomplish its mission of mapping in a relatively short time period of 30 to 45 minutes. In addition, in large forestry mapping, camera, communication, and payload settings may further reduce the maximum endurance of drones in the air. With a single drone, the total required mission time to cover all the area is prolonged, not only producing a high cost for a drone service provider but also having more uncertainty....

[hal-02267430] Shipborne vertical profiles of dust aerosols obtained with Unmanned Aerial Vehicles in the Mediterranean and the Middle East: First results of the AQABA campaign

Publications ENAC - Wednesday, 21 August 2019 - 16:30:47
Atmospheric aerosols have a large role in the earth climate through direct or indirect effects on the radiative energy budget. As the aerosol characteristics are highly variable spatially and in time, observations of these characteristics are needed in regions, where the climate change effects are the most severe. One of these types of hotspots is the East Mediterranean and Middle East (EMME region) (Lelieveld et al., 2012), however, high quality in-situ observations in the Middle East and Arabian Peninsula region are still missing. To gain such a high quality observations in this region, the "Air Quality and climate change in the Arabian Basin" (AQABA)...

[tel-02267558] Fault Detection and Diagnosis for Drones using Machine Learning

Publications ENAC - Tuesday, 20 August 2019 - 12:28:20
This new era of small UAVs currently populating the airspace introduces many safety concerns, due to the absence of a pilot onboard and the less accurate nature of the sensors. This necessitates intelligent approaches to address the emergency situations that will inevitably arise for all classes of UAV operations as defined by EASA (European Aviation Safety Agency). Hardware limitations for these small vehicles point to the utilization of analytical redundancy, rather than to the usual practice of hardware redundancy in manned aviation. In the course of this study, machine learning practices are implemented in order to diagnose faults on a small fixed-wing UAV to avoid...

[hal-02267170] On the Use of Generative Adversarial Networks for Aircraft Trajectory Generation and Atypical Approach Detection

Publications ENAC - Tuesday, 20 August 2019 - 11:29:28
Aircraft approach flight path safety management provides procedures that guide the aircraft to intercept the final approach axis and runway slope before landing. In order to detect atypical behavior, this paper explores the use of data generative models to learn real approach flight path probability distributions and identify flights that do not follow these distributions. Through the use of Generative Adversarial Networks (GAN), a GAN is first trained to learn real flight paths, generating new flights from learned distributions. Experiments show that the new generated flights follow realistic patterns. Unlike trajectories generated by physical models, the proposed...

[hal-02267452] Policy Optimization in Automated Point Merge Trajectory Planning: An Artificial Intelligence-based Approach

Publications ENAC - Tuesday, 20 August 2019 - 11:29:49
Air traffic management is a complex decision making process. Air traffic controllers decision on aircraft trajectory control actions directly lead to the efficiency of traffic flow management. This paper aims to realize an automated routine trajectory management in terminal manoeuvring area with an intelligent decision making agent. An artificial intelligence based approach is applied to adaptively and smartly integrate four types of deconflict actions for resolving conflicts. Especially, the reinforcement learning policy optimization process is discussed in detail. Firstly, application of reinforcement learning in adaptive trajectory planning is presented. The entire...

[hal-02073283] Preconditioned P-ULA for Joint Deconvolution-Segmentation of Ultrasound Images - Extended Version

Publications ENAC - Saturday, 3 August 2019 - 03:43:12
Joint deconvolution and segmentation of ultrasound images is a challenging problem in medical imaging. By adopting a hierarchical Bayesian model, we propose an accelerated Markov chain Monte Carlo scheme where the tissue reflectivity function is sampled thanks to a recently introduced proximal unadjusted Langevin algorithm. This new approach is combined with a forward-backward step and a preconditioning strategy to accelerate the convergence, and with a method based on the majorization-minimization principle to solve the inner non-convex minimization problems. As demonstrated in numerical experiments conducted on both simulated and in vivo ultrasound images, the proposed...

[hal-02194727] Les fonctions d'onde externe et interne : une double solution à la Louis de Broglie ?

Publications ENAC - Saturday, 27 July 2019 - 03:18:11
Nous proposons une grille de lecture de la mécanique quantique correspondant aux spécifications de la théorie de la double solution de Louis de Broglie. Le principe est de décomposer l'évolution d'un système quantique sous la forme de deux fonctions d'onde : une fonction d'onde externe correspondant à l'évolution de son centre de masse et une fonction d'onde interne correspondant à l'évolution de ses variables internes dans le référentiel du centre de masse. La décomposition mathématique n'est possible que dans certains cas car de nombreuses interactions relient ces deux parties. En outre, ces deux fonctions d'onde vont avoir des sens et des interprétations différentes....

[hal-02191101] A New Cycle-Slip Detection Algorithm for Network RTK Using Optimal Dual-Frequency Carrier-Phase Combinations

Publications ENAC - Wednesday, 24 July 2019 - 16:28:23
Many strategies for treating dual-frequency cycle slip have been studied over the years; however, the conventional method using the Melbourne-Wübbena (MW) combination is vulnerable to pseudorange multipath effects. In this paper, we propose a new detection algorithm of dual-frequency cycle slip using only carrier-phase stationary observations for the network real-time kinematic (RTK) system which generates high-precision corrections for user. Two independent and complementary carrierphase combinations, called the ionospheric negative (IN) and ionospheric positive (IP) combinations in this paper, are employed for avoiding insensitive pairs. They can successfully detect...

[hal-02192467] Performance Improvement of Time-Differenced Carrier Phase Measurement-Based Integrated GPS/INS Considering Noise Correlation

Publications ENAC - Wednesday, 24 July 2019 - 11:30:17
In this study, we combined a time-differenced carrier phase (TDCP)-based global positioning system (GPS) with an inertial navigation system (INS) to form an integrated system that appropriately considers noise correlation. The TDCP-based navigation system can determine positions precisely based on high-quality carrier phase measurements without difficulty resolving integer ambiguity. Because the TDCP system contains current and previous information that violate the format of the conventional Kalman filter, a delayed state filter that considers the correlation between process and measurement noise is utilized to improve the accuracy and reliability of the TDCP-based GPS/...
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