Real-time Locating Systems for indoor applications : the methodological customization approach

Sammanfattning: Emerging wireless technologies increase the potential and effectiveness of wireless Real-time Locating Systems (RTLSs), which precisely localize the position, and identify things and people in real time. Among many applications, RTLSs are widely used in the industrial sector for indoor logistics and safety applications. However, signal interferences, which affect the system’s performance, are a serious issue of all indoor RTLS applications. Among others, the interferences are caused by the changeable working environment, the geometry and structure of the space, furnishing, and other obstacles. A customization of the RTLS’s architecture and localization algorithm may provide a way to overcome the interference problem and then enhance the systems’ performance.The objective of this thesis is to develop and implement customization methods, which enhance system performance in the changeable working environment without compromising the functional and non-functional requirements defined by future users and stakeholders. The customized solution is to be based on the comprehensive methodological analysis of the system’s technical and environmental constraints, along with the requirements specified by the application field. The customization process covers the selection, adjustment and adaptation of the wireless technologies and methods in order to enhance the location system’s performance, in terms of accuracy and precision without compromising its simplicity and price.In this research, wireless technologies of Radio Frequency Identification (RFID) and Ultra-wideband (UWB) are applied. The related indoor localization methods, such as, ranging techniques based on Received Signal Strength (RSS) and Angle of Arrival (AoA), are a thesis focus. Moreover, estimation methods like Fingerprinting and Angulation are used.One of the proposed customization methods of RFID-based 3D RTLS, refers to the heuristic analysis-based optimization of a number and configuration of readers. For the same type of system, an alternative way of performance improvement is a customization of localization algorithm, explicitly the Neural Network-based estimation algorithm and its structural features and training methods.Also in this thesis, performance improvement methods of the AoA-based RTLS operating in an UWB technology are proposed. The proposed customization of this system type is based on the uncertainty pattern defined by a statistical uncertainty model, which maps the localization uncertainty in terms of precision in the 2D workspace. The model depicts how the localization uncertainty depends on an arrangement of Location Sensors and workspace geometry. Another proposed customization method is realized by defining and implementing correction vectors for different working environments, which enhance the system’s performance in terms of its accuracy.This thesis consists of two parts. Part I, Prolegomena, presents the overview of applied theories and research methods. This part aims to illustrate the links between the articles constituting the second part of the dissertation. Part II, Papers consists of five reformatted papers already published in peer reviewed journals and conferences.