Architecture de traitement du signal pour les couches physiques très haut débit pour les réseaux de capteur : Application à la métrologie dans un contexte aéronautique et spatial

Signal processing architecture for high-speed physical layers for wireless sensor networks : application for metrology in an aerospace context

• Auteur / Autrice : Julien Henaut
• Direction : Daniela Dragomirescu, Robert Plana
• Type : Thèse de doctorat
• Discipline(s) : Micro et Nanosystèmes
• Date : Soutenance le 26/04/2013
• Etablissement(s) : Toulouse, INSA
• Ecole(s) doctorale(s) : École doctorale Génie électrique, électronique, télécommunications et santé : du système au nanosystème (Toulouse)
• Partenaire(s) de recherche : Laboratoire : Laboratoire d'Analyse et d'Architecture des Systèmes (Toulouse ; 1968-....)
• Jury : Président / Présidente : Etienne Sicard
• Jury : Examinateurs / Examinatrices : Daniela Dragomirescu, Philippe Chevalley
• Jury : Rapporteurs / Rapporteuses : Patrick Garda, Olivier Sentieys

Mots clés

Mots clés contrôlés

Systèmes de télécommunications à large bande

Multiplexage par répartition orthogonale de la fréquence

Réseaux de capteurs (technologie)

Jauges de contrainte

Capteurs de pression

Mots clés libres

MB-OFDM

UWB

Haut débit

Réseaux de capteurs sans fil

Métrologie

MB-OFDM

UWB

High Data Rate

Wireless sensors network

Metrology

Résumé

Lors du développement d’un nouvel avion, la phase précédant l’obtention du certificat de navigabilité est basée sur de nombreux essais au sol ou en vol. Dans le domaine spatial, le lancement est l’une des phases les plus critiques pour les systèmes et des essais au sol particulièrement rigoureux sont donc réalisés afin de vérifier que la charge utile ne sera pas endommagéeDes milliers de capteurs de pression ou de jauges de contrainte sont ainsi utilisés par les industriels du secteur pour ce type d’essais. Mais tous ces éléments sont aujourd’hui connectés par des fils, ce qui engendre des contraintes de temps, de coût et de limitation du nombre de capteurs. Leur remplacement par des réseaux de capteurs sans fil est une solution évidente qui permet également d’augmenter le nombre de points de mesure. Cependant, il n’existe aujourd’hui aucun protocole permettant de répondre aux attentes et besoins des professionnels de l’aéronautique et du spatial. Les travaux présentés dans cette thèse ont ainsi vocation à répondre aux besoins d’un canal de communication très haut débit, basse consommation, à faible puissance d’émission, fiable et autorisant un grand nombre de nœuds. Un prototype de couche physique basée sur un système OFDM ultra large bande a été réalisé, testé et validé, et permet d’atteindre un débit de plus de 200 Mbits/s.

To evaluate a system's compliance with its specified requirements, Hardware System Testing is conducted on the complete and integrated system. This phase is essential in all industry branches, especially in the very regulated and critical aerospace world. In the final phase of the development of an airplane, flight test equipment gathers and analyzes data during flight to evaluate the flight characteristics of the aircraft and validate its design, including safety aspects. One of the most critical tests is the measure of the pressure around the wings during flight. All new aircrafts are computer designed with the use of virtual wind tunnels. So very accurate measures have to be done on the aircraft to validate the model before the aircraft can be industrially produced. In the case of satellites, vibration and mechanical stress are two critical phenomena a satellite endures during launch. This is leading to the necessity for accurate ground tests using strain gauges or thermal sensors before allowing a launch. All such systems used by aircraft and satellite manufacturers today are wired systems. Sensors put around the wings or inside the satellite compartments are wired to a concentrator inside the cabin or the operator’s room. Although good performances are observed in terms of measurement accuracy, these systems have strong drawbacks. The two most important ones are the weight and the cost of both the systems and their installation. An additional drawback concerning its use on aircrafts is due to the installation of a system that increases the weight of the aircraft and immobilizes it during many weeks due to the routing of every cable inside the wings. The cost and the complexity of such systems don’t allow a great number of measurement points. The replacement of conventional measurement networks by wireless sensor networks is not an obvious solution. Despite the great interest in wireless sensor networks in the recent years, the technological barriers are still very numerous and there is currently no protocol to meet the expectations and needs of aviation professionals. The work presented in this thesis aims to meet the needs of a high-speed, low power consumption, low emission and reliable communication layer. Measurements have been performed in real conditions using commercial devices based on the protocol MB-OFDM/Wimedia, the most common standard that approach the need expressed, and have served to define the basis of the study and have helped to select best development tracks. Measurements have demonstrated also the specificity of the propagation channel. In order to reduce the time between the choice of algorithms and their testing in real conditions, it became necessary to use a design flow called Specification - Exploration – Improvement based on automatic synthesis tools. This development cycle has identified specific material needs for the design of the demonstrator.The physical layer is based on an OFDM system and UWB to achieve a data rate of over 150 Mb/s. A fully functional demonstrator, implemented on FPGA and composed of four communicating nodes was presented and has been used to validate the physical layer. Finally first steps to develop a digital ASIC are presented to achieve the goal of low power consumption