Binnenhuis plaatsbepaling door middel van multipath assisted angle of arrival metingen

摘要

Indoor positioning systems enable a broad range of location aware applications, ranging from guidance and tracking to position based entertainment. A multitude of localization systems exists, but Radio Frequency (RF) technologies are mostly preferred, due to the omnipresence of wireless communication infrastructure and handsets. However, the localization accuracy is often impaired by Non-Line-Of-Sight (NLOS) connections and indoor multipath effects, driving further research in this domain. An interesting evolution in widely deployed communication systems is the transition to multi-antenna devices with beamforming capabilities. These properties form an opportunity for localization methods based on Angle of Arrival (AoA) estimation.This work investigates how multipath propagation can be exploited to enhance the accuracy of AoA localization systems. The presented multipath assisted method resembles a fingerprinting approach, matching an AoA measurement vector to a set of reference vectors. In contrast to common fingerprinting systems, reference data is not generated by labor intensive site surveying. Instead, a ray tracer is developed, simulating Line-Of-Sight (LOS) and specularly reflected multipath components based on a-priori known floor plan information. For the calculation of AoA measurement vectors, the established MVDR, MUSIC and ESPRIT algorithms are employed. The resulting algorithm requires only one fixed receiving antenna array to determine the position of a mobile transmitter in a room.The proposed method is implemented in a Matlab framework for indoor positioning, allowing an extensive optimization and evaluation of the developed localization algorithms. All tests are performed in LOS and NLOS conditions, providing insights in the robustness of the system. For the acquisition of real-world measurement data, a flexible hardware setup is designed, consisting of a linear synthetic antenna array for the 2.4 GHz and 5 GHz bands. The measurements are performed in various environments, allowing an assessment of localization accuracy as a function of building materials and room sizes. Also, the performance of the implemented multipath simulator is examined. At the infrastructure side, multiple hardware parameters are investigated, for example the size of the antenna array, the number of arrays and their geometrical organization, the operating frequency, the number of array snapshots, etc. Finally, the combination of AoA with received signal strength and time of flight techniques is demonstrated within the same localization framework.In order to assess the added value of simulating multipath components, all measurements are processed by the multipath assisted AoA method, as well as a standard AoA approach. These tests indicate the superior accuracy of the multipath assisted method, especially in NLOS conditions. Furthermore, the performance of the presented system is compared to results in literature. This leads to the conclusion that the proposed system yields a considerable accuracy improvement over similar RF positioning systems.