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Journal of Applied Geodesy

Editor-in-Chief: Kahmen, Heribert / Rizos, Chris

CiteScore 2018: 1.61

SCImago Journal Rank (SJR) 2018: 0.532
Source Normalized Impact per Paper (SNIP) 2018: 1.064

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Volume 13, Issue 1


Trilateration approaches for seamless out-/indoor GNSS and Wi-Fi smartphone positioning

Guenther Retscher
  • Corresponding author
  • Department of Geodesy and Geoinformation, Research Group Engineering Geodesy, TU Wien, Gusshausstrasse 27-29 E120/5, 1040 Vienna, Austria
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/ Jonathan Kleine / Lisa Whitemore
Published Online: 2018-10-19 | DOI: https://doi.org/10.1515/jag-2018-0022


More and more sensors and receivers are found nowadays in smartphones which can enable and improve positioning for Location-based Services and other navigation applications. Apart from inertial sensors, such as accelerometers, gyroscope and magnetometer, receivers for Wireless Fidelity (Wi-Fi) and GNSS signals can be employed for positioning of a mobile user. In this study, three trilateration methods for Wi-Fi positioning are investigated whereby the influence of the derivation of the relationship between the received signal strength (RSS) and the range to an Access Points (AP) are analyzed. The first approach is a straightforward resection for point determination and the second is based on the calculation of the center of gravity in a triangle of APs while weighting the received RSS. In the third method a differential approach is employed where as in Differential GNSS (DGNSS) corrections are derived and applied to the raw RSS measurements. In this Differential Wi-Fi (DWi-Fi) method, reference stations realized by low-cost Raspberry Pi units are used to model temporal RSS variations. In the experiments in this study two different indoor environments are used, one in a laboratory and the second in the entrance of an office building. The results of the second and third approach show position deviations from the ground truth of around 2 m in dependence of the geometrical point location. Furthermore, the transition between GNSS positioning outdoors and Wi-Fi localization indoors in the entrance area of the building is studied.

Keywords: Smartphone localization; Trilateration; Differential Wi-Fi (DWi-Fi); Indoor positioning; Seamless transition from outdoor to indoor; Performance analysis


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About the article

Received: 2018-06-29

Accepted: 2018-09-20

Published Online: 2018-10-19

Published in Print: 2019-01-28

Citation Information: Journal of Applied Geodesy, Volume 13, Issue 1, Pages 47–61, ISSN (Online) 1862-9024, ISSN (Print) 1862-9016, DOI: https://doi.org/10.1515/jag-2018-0022.

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