Feasibility of Indoor Localization using Angle of Arrival with Low Complexity Hardware

Owing to the enormous growth of the number of devices with wireless connectivity, for example smartphones and tablets but also healthcare monitors, object and device localization has become important. Besides the integration of Global Positioning System (GPS) sensors to localize objects and find locations outdoor, the number of applications collecting indoor location related information is uncountable. Currently developed applications are designed to incorporate indoor location depending functionality.nbsp;example one can use a mobile guide to accompany visitors in an exhibition, monitor elderly people at home or trace goods in a warehouse. The needed localization accuracy is strongly application dependent. This PhD intends to demonstrate the feasibility ofnbsp;Angle of Arrival localization algorithm to perform object localization within buildings. Therefore, a linear phased antenna array operating at 2.435 GHz is designed,nbsp;the intention to develop low complexity hardwarenbsp;on off-the-shelf components. The collected data samples are processed using different direction finding algorithms. Thenbsp;Multiple Signal Classification (MUSIC) and Estimation of Signal Parametersnbsp;Rotational Invariance Techniques (ESPRIT) algorithms are elaborated. Both the implemented algorithm as well asnbsp;antenna array architecture introduce inaccuraciesnbsp;determining the incident angle of a transmitting source. On one hand, the estimated direction will deviate from thenbsp;angle, it is callednbsp;angular measurement error. On the other hand, thenbsp;lobe of the total radiation patternnbsp;a certain beamwidth making the defined transmitternbsp;a markednbsp;instead of an exactnbsp;Both inaccuracies lead to undesired, but inevitable localization errors. Within the context ofnbsp;research two main tracksnbsp;followed. Firstly, this study investigates what interspacing is needed between multiple coherent sources to benbsp;to distinguish among them. Hence, the resolution of the measurement system is determined, based on the knowledge of the beamwidths. Through theoretical simulations and practical measurements, in the anechoic room, the feasible resolution is defined and shown to be related to thenbsp;dimensions andnbsp;source position. Secondly, it is intended to predict theoretically what localization errornbsp;be expected due to the angular measurement error whenever estimating the incident transmitter angle. Practical measurement results obtained in the anechoic roomnbsp;an empty room introducing reflections, must verify these predictions. Theynbsp;us to make statements concerning common angular measurement errors and thus localization errors feasible with Angle of Arrival localization deployed onto low complexity hardware.status: publishe