Estimation of position and orientation of mobile systems in a wireless LAN

In this paper, a method to estimate position and orientation of a mobile system in an indoor scenario is described. The proposed method for localizing the mobile system is based on the use of signal strength values of WLAN access points in range. A radio map based method and Euclidean distance in combination with Delaunay triangulation and interpolation is proposed. The radio map method is divided in two phases. In the initial calibration phase, the radio map is built by moving around and storing signal strength values of an omnidirectional antenna and a beam antenna at various predefined points of the indoor environment. In the localization phase the mobile system moves in the same environment and the localization engine estimates position and orientation of the system. The main disadvantage of radio map based methods is the high manual effort to build the map in the calibration phase. The use of Delaunay triangulation and interpolation allows a radio map with a low density of calibration points and reduces the time for manual generation of the map. The paper presents the experimental results of measurements in an office building.