Συστήματα προσδιορισμού θέσης σε εσωτερικούς χώρους
Indoor positioning systems
Πασιάς, Απόστολος Α.
KeywordsΑσύρματα δίκτυα ; Ραδιοσήματα ; Εντοπισμός θέσης με δορυφόρους ; Global Positioning System ; Indoor Positioning System ; Satellite based positioning ; Global Navigation Satellite Systems
Since its presence on Earth, the man wanted to know his position and orientation. For this purpose he used methods that could understand in every stage of its evolution. From the observation of visible celestial bodies, nowadays he uses satellites and dissemination of electromagnetic waves. Positioning (or localization) in general is the process of determining the position of an object or person in the field. This thesis studies the various techniques and methods applied to our days for indoor positioning The first chapter is to familiarize the reader with the problem of positioning in general. The second chapter is an initial identification of the problem and its parameters and a description of the components of an IPS (Indoor Positioning System). The third chapter includes the most commonly used classifications of IPS systems, based on various criteria such as the area of application, measurement of the distance, architecture and technology, etc. The fourth chapter is an extensive report on the methods and techniques used by the positioning system outdoors and indoors. For the outdoors there is a brief reference to the GNSS systems (Global Navigation Satellite Systems), focusing on GPS (Global Positioning System). Especially for the GPS there is an overall description of calculations and methods that are used. Then follows a comprehensive description of the methods and techniques used in the calculation of distances (TOA, TDOA, AOA, RSS, RTT) and position calculation algorithm (triangulation, trilateration, Fingerprinting). Fifth chapter presents the wireless communication technologies used in IPS systems. Reference is made to WLAN technologies, WiFi, Bluetooth, Infrared, Ultrasound and RFID tags. The sixth chapter describes the deterministic and stochastic radio propagation models and presents their propagation mechanisms (free space propagation, reflection, diffraction, scattering) and the phenomenon of Multipath. Also contains a first reference to the effect of any propagation mechanism to IPS systems. In chapters seven and eight, there are some examples of the ways the position information produced by IPS systems can be used by location based and location aware applications. Chapter nine presents some IPS systems (Active Bat, Cricket, Sonitor, etc.) provided as ready solutions with a comparative report on their advantages and disadvantages. Chapter ten is the conclusion of this thesis, about the methods and techniques that are used in positioning indoors and their evolution margins.