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Accuracy and precision are key parameters in the definition of indoor positioning systems. We want to provide a mobile robot with the capacity to autonomously determining its location inside buildings, to allow it to autonomously navigate. The solution developed is based on spreading emitter beacons of Bluetooth Low Energy in the building and use location finding techniques to determine the robot's location. The main challenge is the capacity to obtain accurate readings of signal strength and the low repeatability of readings even under unchanged conditions. To improve the signal strength measurements it is necessary to deal with this imprecision. Our approach is based on the use of Fuzzy Logic to deal with the accuracy problem. Once better signal strength readings are achieved, using this method, approximate distances are calculated based on signal strength and the trilateration method is implemented to provide the location of the mobile robot.

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A word of appreciation for the staff of Holos for all the help they have given me in the development of this dissertation and in solving some problems in its implementation. In particular, a special thanks to Sérgio Onofre for his precious help and enormous patience.To all my college mates who have contributed in some way to my academic journey, I owe a special thanks, since without them none of this had been possible. I would like to highlight two colleagues who have followed me in this course more closely, André Cardoso and Filipe Perestrelo, whom I thank for the friendship and companionship in these five years of course.A big thank you to my mother, my siblings, and my grandmother for all the support they gave me in the good and bad times of my academic journey. A word still to Eng. Rosário Orvalho, who encouraged me to follow this course and to whom I owe a very special thanks.ix AbstractWhether for work or leisure, we see a large number of people traveling by train every day. In order to ensure the comfort and safety of passengers, it must be checked whether the composition is working normally. For this purpose, a constant monitoring of a train must be done, followed by a diagnosis of the composition, prediction of failures and production of alarms in the event of any anomaly.To perform monitoring on a train, it is necessary to collect data from sensors distributed along its carriages and send them to a software system that performs the diagnosis of the composition in a fast and efficient way.The description of the activities necessary for monitoring of a train immediately refers to topics such as distributed systems, since the intended system will have to integrate several sensors distributed along the train, or Smart Systems, since each sensor must have the capacity to not only acquire data, but also transmit it, preferably, wirelessly.However, there are some obstacles to the implementation of such a system.Firstly, the existence of sources of distortions and noise in the medium interferes both in the acquisition and transmission of data and secondly the fact that the sensors distributed along the train are not prepared to be connected directly to a software system.This dissertation seeks to find a solution for the problems described by implementing a data acquisition system that is distributed and takes advantage of x the current technologies of low-cost sensor nodes as well as web technologies for sensor networks.Keywords: distortion, noise, distributed systems, Smart Systems, SmartSensors, data acquisition, digital processing xi ResumoQuer seja por trabalho ou por lazer, vemos todos os dias um grande número de pessoas a viajarem de comboio. De modo a garantir o conforto e segurança dos passageiros, deve de se verificar se a composição está a funcionar normalmente e se não existe o risco de suceder algum acidente.Para isso, deve de se fazer uma monitoração constante do comboio seguida de um diagnóstico da composição, predição de avarias e produção de alarmes no caso de se verificar alguma anomalia.Para ...