Accurate Mapping of Wi-Fi Access Point Location For Indoor Positioning

R.M. Sabri, T. Arslan

Abstract:	Over the years, several Wi-Fi based indoor positioning systems have been proposed. One example utilizes the triangulation principle, where user’s position is computed based on its distances to at least 3 nearby Wi-Fi access points (APs) whose locations are known. However, for majority of Wi-Fi network deployments, the AP’s physical locations are not always readily available. Therefore, a mechanism that can map AP locations efficiently and accurately for an indoor positioning system is highly desirable. This paper proposes a novel algorithm that could locate Wi-Fi AP with improved accuracy by post-processing the spatial received signal strength (RSS) information derived from network stumbling. The algorithm first constructs spatial boundary and search grids given the Wi-Fi stumbling data. Then it determines which search grid the AP of interest might be located by interpolating the stumbling data to arrive at signal strength value typically seen at the source of RF transmission. This is achieved by fitting well known radio propagation model to the stumbling data at each search grid. Finally, the algorithm searches for a region where the AP is most probably located. This region is determined by choosing search grid(s) where the sums of squared errors between the actual and calculated RSS values are minimized. The final AP location is determined by computing the centre of mass of the chosen area. Result of our proposed algorithm is compared to other AP positioning methods in the literature.
Published in:	Proceedings of the 23rd International Technical Meeting of the Satellite Division of The Institute of Navigation (ION GNSS 2010) September 21 - 24, 2010 Oregon Convention Center, Portland, Oregon Portland, OR
Pages:	3376 - 3379
Cite this article:	Sabri, R.M., Arslan, T., "Accurate Mapping of Wi-Fi Access Point Location For Indoor Positioning," Proceedings of the 23rd International Technical Meeting of the Satellite Division of The Institute of Navigation (ION GNSS 2010), Portland, OR, September 2010, pp. 3376-3379.
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