Location identification using a magnetic-field-based FFT signature

User indoor positioning has been under constant improvement especially with the availability of new sensors integrated to the modern mobile devices. These sensory devices allow us to exploit not only infrastructures made for every day use, such as Wifi, but also natural infrastructure, as is the case of natural magnetic fields. In this work, we propose a novel approach that takes advantage of the benefits of using the magnetic sensor incorporated in most modern mobile devices, and the negligible variations of the Earth's magnetic field to position an individual with high accuracy. Most importantly, the methodology proposed allows us to avoid the burden of having to collect magnetic information in different directions in order to construct an accurate magnetic map, showing an improvement on methods that require the individuals to construct bigger magnetic maps that contain redundant information such as magnitude in different directions

Node localization in underwater sensor networks (UWSN)

This dissertation focuses on node localization in underwater wireless sensor networks (UWSNs) where anchor nodes have knowledge of their own locations and communicate with sensor nodes in acoustic or magnetic induction (MI) means. The sensor nodes utilize the communication signals and the locations of anchor nodes to locate themselves and propagate their locations through the network. For UWSN using MI communications, this dissertation proposes two localization methods: rotation matrix (RM)-based method and the distance-based method. Both methods require only two anchor nodes with arbitrarily oriented tri-directional coils to locate one sensor node in the 3-D space, thus having advantages in a sparse network. Simulation studies show that the RM-based method achieves high localization accuracy, while the distance-based method exhibits less computational complexity. For UWSN using acoustic communications, this dissertation proposes a novel multi-hop node localization method in the 2-D and 3-D spaces, respectively. The proposed method estimates Euclidean distances to anchor nodes via multi-hop propagations with the help of angle of arrival (AoA) measurements. Simulation results show that the proposed method achieves better localization accuracy than existing multi-hop methods, with high localization coverage. This dissertation also investigates the hardware implementation of acoustic transmitter and receiver, and conducted field experiments with the hardware to estimate ToA using single pseudo-noise (PN) and dual PN(DPN) sequences. Both simulation and field test results show that the DPN sequences outperform the single PNs in severely dispersive channels and when the carrier frequency offset (CFO) is high --Abstract, page iv

Mindful navigation with guiding light : design considerations for projector based indoor navigation assistance system

Thesis (Ph. D.)--Massachusetts Institute of Technology, School of Architecture and Planning, Program in Media Arts and Sciences, 2012.Cataloged from PDF version of thesis.Includes bibliographical references (p. 113-117).People can easily become mindless in their decision-making and become disengaged from their surroundings when their actions depend on information and guidance from an assistive technology. Research has shown how automated navigation assistance systems lead users to be disengaged from the space through which they are traveling, resulting in poor recollection of the environment and poorer situational decision-making. This disengagement and mindlessness can potentially increase the risk of accidents and lower the quality of user experience. If we can help people become mindfully attentive to the environment and surroundings while carrying out navigation tasks using assistive technologies, I hypothesize that we will have better memory of the space, improved cognitive reconstruction of environment, and better understanding of the immediate situation, all of which will lead to better decision making and more efficient navigation. In this work, I present a new approach for analyzing the problem of navigation assistance for pedestrians, which considers both the physical and psychological constraints of users focused on navigation. I address the physical constraint that eyes should remain "on the street" by providing a new visual interface, named Guiding Light, that offers a mixed reality presentation of guidance information in the environment itself, instead of on a screen. We address the psychological constraint that minds should remain engaged with the environment by applying a framework based on mindfulness and mindlessness theory (Langer 1989) in the design of the system. The theory explains how mindsets affect engagement levels and decision-making in daily activities. In addition, this thesis describes an indoor positioning technology that provides relatively high accuracy localization and heading orientation of a user in indoor environments. The innovation not only involved developing a new sensor but also a software system to collect fingerprint maps and tracking location with the fingerprint maps. This new technology opens up a new area in the field to explore other possibilities of using a magnetic field based positioning system.by Jaewoo Chung.Ph.D

A fuzzy logic approach to localisation in wireless local area networks

This thesis examines the use and value of fuzzy sets, fuzzy logic and fuzzy inference in wireless positioning systems and solutions. Various fuzzy-related techniques and methodologies are reviewed and investigated, including a comprehensive review of fuzzy-based positioning and localisation systems. The thesis is aimed at the development of a novel positioning technique which enhances well-known multi-nearest-neighbour (kNN) and fingerprinting algorithms with received signal strength (RSS) measurements. A fuzzy inference system is put forward for the generation of weightings for selected nearest-neighbours and the elimination of outliers. In this study, Monte Carlo simulations of a proposed multivariable fuzzy localisation (MVFL) system showed a significant improvement in the root mean square error (RMSE) in position estimation, compared with well-known localisation algorithms. The simulation outcomes were confirmed empirically in laboratory tests under various scenarios. The proposed technique uses available indoor wireless local area network (WLAN) infrastructure and requires no additional hardware or modification to the network, nor any active user participation. The thesis aims to benefit practitioners and academic researchers of system positioning