Archives Ouvertes HAL
Toutes les publications de l'ENAC en direct.
All ENAC publications.
[tel-05100592] Impact of DME/TACAN multipath on future civil aviation GNSS receivers
In the upcoming years, civil aviation will adopt a new generation of Global Navigation Satellite System (GNSS) receivers, referred to as the Dual Frequency Multi-Constellation (DFMC) receivers. Unlike the legacy GNSS receivers, DFMC GNSS receivers will be capable of processing both the GNSS L1/E1 and the GNSS L5/E5a signals. Thanks to the combination of these signals in both frequency bands, the civil aviation DFMC GNSS receivers are expected to have better performances than the legacy GNSS receivers. One challenge associated with the processing of the GNSS L5/E5a signals for a civil aviation GNSS receiver is the sharing of the same Aeronautical Radionavigation Service...
[hal-05086025] Aerostructural optimization of high-aspect-ratio wings: navigating complex trade-offs
A promising innovation path in aircraft design aimed at improving fuel effi- ciency and reducing emissions is the adoption of concepts featuring increased wing aspect ratios. This study investigates the aerostructural optimization of high aspect ratio (HAR) wings using the uCRM-13.5 benchmark and the OpenAeroStruct framework. The impact of model fidelity, objective metrics, analysis methods, and material selection on optimal wing design is examined. Results showed that neglecting viscous and compressibility effects leads to unrealistic designs, with fuel burn underestimated by up to 45%. Mid-fidelity mod- els, which combine a vortex lattice method-based aerodynamic model...
[hal-05091694] HgTe Nanocrystals Carrier Density and Its Tuning
HgTe nanocrystals (NCs) are now an established material for colloidal optoelectronics. In the mid-and far-infrared range, there is to date no viable colloidal alternative material that can emit or detect light with such a high efficiency. Advancements have been rapid, primarily concentrating on the direct application of the narrow bandgap material spectrum in devices. However, certain material properties, such as carrier density, have been suboptimally addressed, despite their critical importance to device design. Therefore, this review aggregates most of the recent developments related to the determination and control of the carrier density with HgTe NCs. The manuscript...
[hal-05088148] BiCoq : Bigraphs Formalisation with Coq
Bigraphs are a formal model for representing (ubiquitous) systems with strong notations of both space, e.g. a person in a room, and non-spatial relations, e.g. mobile phone communication regardless of location. They have been used in a wide range of scenarios including sensor systems, IoT configuration languages, and communications protocol design. While implementations of the bigraph theory exist, e.g. BigraphER, until now, there has been no attempt to formalise the theory in a theorem prover. We show an implementation of the bigraph theory in the Coq theorem prover, including the main bigraph type specification and common manipulation operators, e.g. composition and...
[hal-05068461] POMDP-based adaptive interaction through physiological computing
In this study, a formal framework aiming to drive the interaction between a human operator and a team of unmanned aerial vehicles (UAVs) is experimentally tested. The goal is to enhance human performance by controlling the interaction between agents based on an online monitoring of the operator’s mental workload (MW) and performance. The proposed solution uses MW estimation via a classifier applied to cardiac features. The classifier output is introduced as a human MW state observation in a Partially Observable Markov Decision Process (POMDP) which models the human-system interaction dynamics, and aims to control the interaction to optimize the human agent’s performance...
[hal-05078907] The Gauge Equation in Statistical Manifolds: An Approach through Spectral Sequences
The gauge equation is a generalization of the conjugacy relation for the Koszul connection to bundle morphisms that are not isomorphisms. The existence of nontrivial solution to this equation, especially when duality is imposed upon related connections, provides important information about the geometry of the manifolds under consideration. In this article, we use the gauge equation to introduce spectral sequences that are further specialized to Hessian structures.
[hal-05080319] PYXIS: A higly predictable toolchain for FPGA circuit production of advanced GNC algorithm
<div><p>The configuration of Field-Programmable Gate Arrays (FPGAs) within the context of command law implementation for aerospace systems is a complex process. In a previous work, we proposed the use of dataflow programming languages as the input for the synthesis process and as an alternative to traditional hardware programming languages. The proposed translation flow has been demonstrated to be faster than current state-of-theart tools while simultaneously offering greater predictability in the inferred hardware component of the design. This paper extends this previous work, addressing identified challenges. A first one is related to the use of a generated circuit to...
[hal-05074724] The Curse of Time Horizon in Detect & Avoid Algorithms
This paper introduces a centralized collision avoidance algorithm based on a Differential Evolution, for the purpose of studying the time horizon effect, a pathological behavior previously identified in Detect & Avoid (D&A) decentralized algorithms based on geometric methods. This pathological behavior, called time horizon effect, is most likely to occur during constant-speed encounters, when the lateral maneuvers issued by the D&A system postpone the crossing of trajectories beyond the horizon of conflict detection by maneuvering the flights toward parallel tracks. In such cases, the flights might end up locked on parallel tracks, missing their destination.</p><p>The...
[hal-05074617] ORCA-A* : A Hybrid Reciprocal Collision Avoidance and Route Planning Algorithm for UAS in Dense Urban Areas
The rapid development of drones (or Unmanned Aerial Systems) and their potential deployment in urban areas poses a number of safety issues. Some degree of automation is most probably necessary to ensure that the UAS missions are safely and efficiently performed in urban environments. In a context where a large number of non-cooperative, noncommunicative UAS would fly in dense urban areas, decentralized and autonomous approaches naturally come to mind. In such approaches, each agent would navigate among the buildings while avoiding the other traffic. ORCA (Optimal Reciprocal Collision Avoidance) is a state-of-the art geometric method for robot collision avoidance that...
[hal-05072620] Optimization of unmanned air vehicles trajectories in urban air mobility
<div><p>We propose a mixed-integer linear programming model to design optimal trajectories of unmanned aerial vehicles in urban airspaces. The model integrates multiple decision levers, and takes account of the drone dynamics as well as of operational constraints characterizing the addressed problem. Two variants of the model are also presented, to the aim of assessing the impact of the optimization levers and their effect on the overall efficiency. Computational experiments demonstrate the scalability and effectiveness of the proposed approach even for high-density urban air traffic.</p></div>