Analyse des signaux transitoires émis par les arcs électriques générés dans les panneaux photovoltaïques

National audienceDes arcs électriques aux conséquences graves peuvent parfois survenir au sein de panneaux photovoltaïques. Cet article décrit un système de détection d'arcs en utilisant deux méthodes différentes, lesquelles sont comparées au niveau des performances de détection. Une méthode de localisation est également décrite et évaluée sur la base de configurations réelles. Enfin, une description du démonstrateur opérationnel développé pour réaliser cette détection et localisation est présentée

Wireless Emitter Location Estimation Based on Linear and Nonlinear Algorithms using TDOA Technique

Low-power devices such as cell phones, and wireless routers are commonly used to control Improvised Explosive Devices (IEDs) and as the communication nodes for the sake of command and control. Quickly locating the source of these signals is ambitious, specifically in a metropolitan environment where buildings and towers may cause intervention. This presents a geolocation system that compounds the attributes of several proven geolocation and error mitigation methods to locate an emitter of interest in an urban environment. The proposed geolocation system uses a Time Difference of Arrival (TDOA) approach to estimate the position of the emitter of interest. Using multiple sensors at known locations, TDOA estimates are achieved by the cross-correlation of the signal received at all the sensors. A Weighted Least Squares (WLS) solution, Linear least Square (LLS) method and maximum likelihood (ML) estimation is used to estimate the emitter's location. If the variance of this location estimate is too high, a sensor is detected and identified as possessing a Non-Line of Sight (NLOS) path from the emitter. This poorly located sensor is then removed from the geolocation system and a new position estimate is computed with the remaining sensor TDOA information. The performance of the TDOA system is determined through modeling and simulations. Test results confirm the feasibility of identifying a NLOS sensor, thereby improving the geolocation system's accurateness in a metropolitan environment

Scalable positioning of commodity mobile devices using audio signals

This thesis explores the problem of computing a position map for co-located mobile devices. The positioning should happen in a scalable manner without requiring specialized hardware and without requiring specialized infrastructure (except basic Wi-Fi or cellular access). At events like meetings, talks, or conferences, a position map can aid spontaneous communication among users based on their relative position in two ways. First, it enables users to choose message recipients based on their relative position, which also enables the position-based distribution of documents. Second, it enables senders to attach their position to messages, which can facilitate interaction between speaker and audience in a lecture hall and enables the collection of feedback based on users’ location. In this thesis, we present Sonoloc, a mobile app and system that, by relying on acoustic signals, allows a set of commodity smart devices to determine their relative positions. Sonoloc can position any number of devices within acoustic range with a constant number of acoustic signals emitted by a subset of devices. Our experimental evaluation with up to 115 devices in real rooms shows that – despite substantial background noise – the system can locate devices with an accuracy of tens of centimeters using no more than 15 acoustic signals.Diese Dissertation befasst sich mit dem Problem, eine Positionskarte von sich am gleichen Ort befindenden mobilen Geräten zu berechnen. Dies soll skalierbar, ohne Verwendung von spezialisierter Hardware oder Infrastruktur (ausgenommen einfache WLAN- oder Mobilfunkzugang) erfolgen. Bei Veranstaltungen wie Meetings, Diskussionen oder Konferenzen kann eine Positionskarte die Benutzer bei spontaner Kommunikation mithilfe der relativen Positionen in zweierlei Hinsicht unterstützen. Erstens ermöglicht sie den Benutzern, die Empfänger von Nachrichten aufgrund deren Position zu wählen, was auch eine positionsabhängige Verteilung von Unterlagen erlaubt. Zweitens ermöglicht sie den Sendern, ihre Position in die Nachrichten zu integrieren, was eine Interaktion zwischen Referent und Zuhörer in einem Hörsaal und die Sammlung von positionsabhängigen Rückmeldungen erlaubt. In dieser Dissertation stellen wir die Mobile-App und das System Sonoloc vor, das mithilfe von Tonsignalen erlaubt, die relative Position handelsüblicher, intelligenter Geräte zu bestimmen. Sonoloc kann eine beliebige Zahl von Geräten innerhalb des Hörbereichs durch eine gleichbleibende Zahl von Tonsignalen, die von einer Teilmenge der Geräte gesendet werden, lokalisieren. Unsere experimentelle Analyse mit bis zu 115 Geräten in echten Räumen zeigt, dass das System trotz signifikanter Hintergrundgeräusche unter Verwendung von bis zu 15 Tonsignalen mit einer Genauigkeit von wenigen Dezimetern Geräte lokalisieren kann.This work was supported in part by the European Research Council (ERC Synergy imPACT 610150), the German Science Foundation (DFG CRC 1223), the Japan Society for the Promotion of Science (Grant-in-Aid for Scientific Research (A), KAKENHI Grant Number 16H01735), and the National Science Foundation (NSF Awards CNS 1526635 and CNS 1314857)

Routing, Localization And Positioning Protocols For Wireless Sensor And Actor Networks

Wireless sensor and actor networks (WSANs) are distributed systems of sensor nodes and actors that are interconnected over the wireless medium. Sensor nodes collect information about the physical world and transmit the data to actors by using one-hop or multi-hop communications. Actors collect information from the sensor nodes, process the information, take decisions and react to the events. This dissertation presents contributions to the methods of routing, localization and positioning in WSANs for practical applications. We first propose a routing protocol with service differentiation for WSANs with stationary nodes. In this setting, we also adapt a sports ranking algorithm to dynamically prioritize the events in the environment depending on the collected data. We extend this routing protocol for an application, in which sensor nodes float in a river to gather observations and actors are deployed at accessible points on the coastline. We develop a method with locally acting adaptive overlay network formation to organize the network with actor areas and to collect data by using locality-preserving communication. We also present a multi-hop localization approach for enriching the information collected from the river with the estimated locations of mobile sensor nodes without using positioning adapters. As an extension to this application, we model the movements of sensor nodes by a subsurface meandering current mobility model with random surface motion. Then we adapt the introduced routing and network organization methods to model a complete primate monitoring system. A novel spatial cut-off preferential attachment model and iii center of mass concept are developed according to the characteristics of the primate groups. We also present a role determination algorithm for primates, which uses the collection of spatial-temporal relationships. We apply a similar approach to human social networks to tackle the problem of automatic generation and organization of social networks by analyzing and assessing interaction data. The introduced routing and localization protocols in this dissertation are also extended with a novel three dimensional actor positioning strategy inspired by the molecular geometry. Extensive simulations are conducted in OPNET simulation tool for the performance evaluation of the proposed protocol