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International audience; Today's technology still limits the accessing to 2D information (images, graphics, charts, maps, paintings, etc.) for visually impaired people (VIP). The main drawbacks are the complexity of spatial information representation and the high cost of the design for man-machine device democratization. Therefore, we present a novel and inclusive haptic architecture to access and interact with 2D data. This architecture relies on the force-feedback principle, and is named Force-Feedback Tablet (F2T). The F2T's architecture is based on a flat thumbstick mounted on a 2D actuated support, enabling force feedback effects on user's finger. The flat thumbstick allows measuring user's intended movements independently from mobile support's actual movements, making possible to develop highly interactive effects, static and dynamic effects, or guidances. Moreover, the mechanical structure does not need to be backdrivable, which simplifies the motion control, and reduces the costs of the device. Finally, the F2T architecture allows designing lightweight, compact and scalable devices. Such devices can assist VIP in their several daily-life tasks. To validate and demonstrate the relevance of the F2T architecture, we present two lightweight prototypes. We use the shape and spatial layout's recognition to test its effectiveness. The VIP and the blindfolded participants confirmed this effectiveness through a series of preliminary experimental haptic recognition tasks. Results obtained during the evaluation are encouraging with high recognition rates for directions, angles, and shapes. As a result, the F2T proved to convey graphical information through force-feedback.; La technologie actuelle est limitée encore dans l'accessibilité aux informations 2D (images, graphiques, cartes, plans, dessins, etc.) pour les personnes présentant une incapacité visuelle. Les contraintes les plus importantes sont la complexité de la représentation de l'information spatiale et le coût élevé du design des appareils pour la communication homme-machine. Nous présentons une nouvelle architecture haptique et inclusive pour l'accès et l'interaction avec des données 2D. Cette architecture se base sur le principe de retour de force et est appelée Tablette à retour de force (F2T). L'architecture de la F2T est basée sur un joystick plat monté sur un support 2D motorisé, exerçant des effets de retour de force sur le doigt de l'utilisateur. Le joystick plat permet la mesure des intentions de mouvement de l'utilisateur indépendamment des mouvements du support mobile, rendant possible le développement des effets interactifs, statiques et dynamiques ou guidages. En plus, la structure mécanique n'a pas besoin d'être mécaniquement réversible, ce qui simplifie le contrôle du mouvement et réduit le coût de l'appareil. Finalement, l'architecture F2T permet le design de dispositifs légers, compacts et évolutifs. Ces dispositifs peuvent aider les déficients visuels dans certaines tâches de tous les jours. Pour valider et démontrer la pertinence de l'architecture F2T, nous présentons deux prototypes légers. Nous utilisons la reconnaissance de forme et du plan spatial pour tester son efficacité. Les participants à nos tests, déficients visuels et les personnes avec les yeux bandés ont confirmé cette efficacité à travers une série de tests préliminaires sur des tâches de reconnaissance haptique. Les résultats obtenus sont encourageants avec un important pourcentage de reconnaissance de directions, angles et formes. Par conséquent, F2T a prouvé sa capacité de transmission d'information graphique à travers le principe de retour de force.

International audience; GNSS brings more signals and more satellites to improve positioning services. This paper introduces data fusion from multiple Global Navigation Satellite System (GNSS) constellations. In fact, some failures in satellite's signals negatively impact the quality of positioning. For this purpose, this paper presents the robust Extended Kalman Filter (robust-EKF) to eliminate the outliers and de-noising method based on the Long Short-Term Memory (LSTM). The algorithms are tested using GPS, Galileo and GLONASS data corresponding to base station ABMF in Guadeloupe. Robust combination of GPS, Galileo, and GLONASS data improve the position accuracy from 41.0% to 95.0% compared to the use of independent systems and by about 84.0% compared to the non-robust combination of GPS, Galileo, and GLONASS data. In particular, the position precision improves significantly using the method LSTM-EKF by about 74.0% compared to the robust-EKF.

This paper presents data fusion from multiple Global Navigation Satellite System (GNSS) constellations. GNSS brings more signals and more satellites to improve the accuracy of user’s position. However, multiple failures in satellite’s signals sometimes negatively impact the determination of the user’s position and should be considered. For this purpose, the present paper provides robust Extended Kalman Filter (robust-EKF) to eliminate the outliers. The algorithms are tested by using GPS, Galileo and GLONASS data corresponding on data from base station GRAC in Grasse, France. Applying the robust-EKF method as well as the robust combination of GPS, Galileo, and GLONASS data improves the position accuracy by about 30.0%, 20.7%, and 90% compared to the use of GPS data only, Galileo data only, and GLONASS data only, respectively, and by about 67% compared to the nonrobust combination of GPS, Galileo, and GLONASS data.

Conductive polymers are a new type of conductive materials that are attractive for application in flexible, and possibly reconfigurable antennas. Two planar elliptical ultra-wideband antennas based on conductive polymers are manufactured. The selected Polypyrrole (PPy) polymer exhibits moderate conductivity but can be produced as rather thick free-standing films up to a size of several hundred micrometers. The efficiency of the conductive materials is estimated based on the comparison of the radiation patterns with those of a reference antenna built from copper. The two PPy samples exhibit the same conductivity, but different thicknesses. Higher efficiency is achieved using the thicker PPy sample, demonstrating efficient operation below one skin depth.

Two 6 GHz microstrip patch antennas made from conducting polymers with relatively low DC conductivity such as PEDOT (10000 S/m) and PPy (2000 S/m) are presented. The performance of these patch antennas is compared with a similar copper patch antenna. The results indicate that it is possible to obtain reasonable performance albeit with modest radiation efficiencies. The PEDOT antenna achieved a maximum gain of 2.2 dB, while the PPy antenna reached a gain of 3.8 dB, as against 6.0 dB for a corresponding Cu patch antenna The results confirm the potential of polymer materials for microwave antennas and suggest that CPs may be of use in other passive microwave circuit applications.

The growth of multi-walled carbon nanotubes (MWNTs) with a large diameter of 200 nm on nickel (Ni) coated silicon wafer at different growth times up to 30 min was investigated. CNT cobwebs were found after a short growth time (7 min) and developed into ordered forests at higher growth times (> 10 min). One of the important formation features of the CNTs in this study was the coaxial structure of the nanotubes, ie. a MWNT within a MWNT. Its formation was due to secondary nanostructures of Ni particles. Unexpected growth of carbon micro-balloons occurred when high flow rates of carbon feedstock was used or when growth time exceeded 15 min.

A Microstrip Patch Antenna (MPA) has been fabricated using a Conducting Polymer (CP), Polypyrrole (PPy) as radiating patch on a transparent 3mm thick Plexiglas™ substrate. The bulk DC conductivity of the PPy patch is 2000 S/m and its thickness 120 µm. The MPA was designed for operating at 2 GHz. A similar antenna with Copper (Cu) patch on Plexiglas™ was also fabricated for validating the simulation of PPy antenna and comparing its performance. The results show that the PPy antenna reaches a gain of 5.01 dB at 2.18 GHz as against 6.26 dB at 2.2 GHz for a corresponding Cu patch antenna. The conduction efficiency of Cu-patch antenna is around 80% while that of PPy-patch antenna is around 60%. The results suggest that it might be possible to use CPs in other passive microwave circuit applications.