Indoor Cooperative Localization for Ultra Wideband Wireless Sensor Networks

In recent years there has been growing interest in ad-hoc and wireless sensor networks (WSNs) for a variety of indoor applications. Localization information in these networks is an enabling technology and in some applications it is the main sought after parameter. The cooperative localization performance of WSNs is ultimately constrained by the behavior of the utilized ranging technology in dense cluttered indoor environments. Recently, ultra-wideband (UWB) Time-of-Arrival (TOA) based ranging has exhibited potential due to its large bandwidth and high time resolution. However, the performance of its ranging and cooperative localization capabilities in dense indoor multipath environments needs to be further investigated. Of main concern is the high probability of non-line of sight (NLOS) and Direct Path (DP) blockage between sensor nodes, which biases the TOA estimation and degrades the localization performance. In this dissertation, we first present the results of measurement and modeling of UWB TOA-based ranging in different indoor multipath environments. We provide detailed characterization of the spatial behavior of ranging, where we focus on the statistics of the ranging error in the presence and absence of the DP and evaluate the pathloss behavior in the former case which is important for indoor geolocation coverage characterization. Parameters of the ranging error probability distributions and pathloss models are provided for different environments: traditional office, modern office, residential and manufacturing floor; and different ranging scenarios: indoor-to-indoor (ITI), outdoor-to-indoor (OTI) and roof-to-indoor (RTI). Based on the developed empirical models of UWB TOA-based OTI and ITI ranging, we derive and analyze cooperative localization bounds for WSNs in the different indoor multipath environments. First, we highlight the need for cooperative localization in indoor applications. Then we provide comprehensive analysis of the factors affecting localization accuracy such as network and ranging model parameters. Finally we introduce a novel distributed cooperative localization algorithm for indoor WSNs. The Cooperative LOcalization with Quality of estimation (CLOQ) algorithm integrates and disseminates the quality of the TOA ranging and position information in order to improve the localization performance for the entire WSN. The algorithm has the ability to reduce the effects of the cluttered indoor environments by identifying and mitigating the associated ranging errors. In addition the information regarding the integrity of the position estimate is further incorporated in the iterative distributed localization process which further reduces error escalation in the network. The simulation results of CLOQ algorithm are then compared against the derived G-CRLB, which shows substantial improvements in the localization performance

A multi-objective approach to indoor wireless heterogeneous networks planning

We present a multi-objective optimization approach for indoor wireless network planning subject to constraints for exposure minimization, coverage maximization and power consumption minimization. We consider heterogeneous networks consisting of WiFi Access Points (APs) and Long Term Evolution (LTE) femtocells. We propose a design framework based on Multi-objective Biogeography-based Optimization (MOBBO). The results of the proposed method indicate the advantages and applicability of the multi-objective approach

The Total In-Flight Simulator (TIFS) aerodynamics and systems: Description and analysis

The aerodynamics, control system, instrumentation complement and recording system of the USAF Total In/Flight Simulator (TIFS) airplane are described. A control system that would allow the ailerons to be operated collectively, as well as, differentially to entrance the ability of the vehicle to perform the dual function of maneuver load control and gust alleviation is emphasized. Mathematical prediction of the rigid body and the flexible equations of longitudinal motion using the level 2.01 FLEXSTAB program are included along with a definition of the vehicle geometry, the mass and stiffness distribution, the calculated mode frequencies and mode shapes, and the resulting aerodynamic equations of motion of the flexible vehicle. A complete description of the control and instrumentation system of the aircraft is presented, including analysis, ground test and flight data comparisons of the performance and bandwidth of the aerodynamic surface servos. Proposed modification for improved performance of the servos are also presented

Mine Shaft Conveyance Monitoring

Technology to enhance safety during mine hoisting has been developed by researchers at the Spokane Research Laboratory of the National Institute for Occupational Safety and Health. Assessment of current hoisting technology suggests that monitoring conveyance position and load directly from the skip or cage top offers several significant safety advantages. Wireless data transmission schemes and a package consisting of sensors, batteries, and a charger mounted on the wire rope and skip have been developed. A state-of-the-art automated hoisting test facility was constructed to test the concept in a controlled laboratory setting. Field tests in a fill-size shaft are underway.1999830

Langattoman anturijärjestelmän suunnittelu hissin kunnonvalvontaan

The aim of this thesis is to design, implement and validate a prototype sensor system for wirelessly monitoring the condition of an elevator. One purpose of such system is long-term monitoring of the elevator, which could help detecting emerging issues in advance. The system could also be used by maintenance personnel as a real-time troubleshooting tool, assisting in device commissioning and maintenance situations, for example. Due to requirements set by the use case and the elevator environment, a wireless, battery operated device is required. A significant part of this thesis focuses on aspects of selecting a suitable wireless technology, as the choice has a large impact on the performance of the system. Different wireless solutions are researched and compared, and a technology using the sub-GHz frequency bands is selected for the prototypes. The prototype sensor is designed based on the choice of the wireless technology. The hardware and software of the sensor nodes, as well as a PC tool for collecting data, are presented. The performance of the sensor nodes and the functionality of the whole sensor system is tested using a batch of manufactured prototype devices. The prototypes and the selection of the wireless technology are considered successful. Minor improvements to the design of the prototypes are presented at the end of the thesis.Tässä työssä suunnitellaan, toteutetaan ja arvioidaan hissin kunnonvalvontaan tarkoitetun langattoman anturijärjestelmän prototyyppi. Järjestelmän käyttötarkoituksena on sekä hissin pitkäaikainen kunnonvalvonta, jonka avulla voidaan havaita orastavia vikoja etukäteen, että mahdollisuus käyttää laitetta reaaliaikaisena vianetsintätyökaluna, jota huoltohenkilöstö voisi käyttää apunaan esimerkiksi hissin käyttöönoton ja huoltotilanteiden yhteydessä. Käyttökohteen asettamien vaatimusten takia on tarpeen suunnitella langaton, paristokäyttöinen anturi. Merkittävä osa tästä työstä käsittelee langattoman teknologian valintaan vaikuttavia tekijöitä, sillä valinnalla on suuri vaikutus järjestelmän suorituskykyyn. Työssä kartoitetaan ja vertaillaan erilaisia langattomia ratkaisuita, joista prototyyppilaitteeseen valitaan sub-GHz-taajuuksia käyttävä langaton teknologia. Anturilaitteen prototyyppi suunnitellaan valitun langattoman teknologian pohjalta. Anturilaitteen elektroniikka, ohjelmisto, ja PC-tietokoneelle toteutettu datankeräystyökalu esitellään. Anturien suorituskyky sekä koko järjestelmän toiminta testataan valmistetuilla prototyyppikappaleilla. Prototyyppi arvioidaan toimivaksi ja langattoman teknologian valinta onnistuneeksi. Työn lopussa esitetään pieniä parannusehdotuksia prototyypin suunnitteluun

SDDV: scalable data dissemination in vehicular ad hoc networks

An important challenge in the domain of vehicular ad hoc networks (VANET) is the scalability of data dissemination. Under dense traffic conditions, the large number of communicating vehicles can easily result in a congested wireless channel. In that situation, delays and packet losses increase to a level where the VANET cannot be applied for road safety applications anymore. This paper introduces scalable data dissemination in vehicular ad hoc networks (SDDV), a holistic solution to this problem. It is composed of several techniques spread across the different layers of the protocol stack. Simulation results are presented that illustrate the severity of the scalability problem when applying common state-of-the-art techniques and parameters. Starting from such a baseline solution, optimization techniques are gradually added to SDDV until the scalability problem is entirely solved. Besides the performance evaluation based on simulations, the paper ends with an evaluation of the final SDDV configuration on real hardware. Experiments including 110 nodes are performed on the iMinds w-iLab.t wireless lab. The results of these experiments confirm the results obtained in the corresponding simulations

Exposure minimization algorithm in homogeneous indoor networks

Due to the increased use of indoor wireless networks and the concern about human exposure to the RF sources, there is a need for network planners for exposure-aware network planning. A heuristic exposure minimization algorithm for indoor WiFi networks is presented and applied to an actual office building. The exposure characteristics of an exposure-optimized network are compared with those of a traditional network deployment

Overview of IEEE802.15.4g OFDM and its Applicability to Smart Building Applications

International audienceThis paper compares the performance of two IEEE802.15.4 physical layers in the Smart Building context: 2.4 GHz O-QPSK and sub-GHz OFDM. The former has been in the IEEE802.15.4 standard since 2003, the latter was rolled into its 2015 revision. OFDM promises exceptional performance, in particular in environments with high external interference and multi-path fading. This paper starts with a comprehensive overview of IEEE802.15.4 and IEEE802.15.4g, with a particular focus on OFDM, its design drivers and modes of operation. The second half of this paper presents results from an exhaustive benchmarking campaign of both technologies in a building environment, and discusses lessons learnt. We show how OFDM has a higher range, even at 400 kbps and 800 kbps data rates. We then quantify the importance of frequency repetition in OFDM, and of using a wide communication channel, and we show how the use of OFDM can result in a 2–4 χ decrease in power consumption compared to 2.4 GHz O-QPSK. We conclude by recommending the use of OFDM option 1, with MCS2 for short (<128 B) frames, and MCS3 otherwise