Abstract
In this paper, we proposed a system which combines two extant positioning systems, which are extant Wi-Fi and PDR (Pedestrian Dead Reckoning) with the smartphone. In the proposed method, we mainly use PDR, and combine a proximity-based correction using several Wi-Fi access points. The PDR uses three sensors, the magnetometer, the accelerometer, and the pressure sensor. The pressure sensor enables the estimate of 3D positions. Also, the proposed system solves the error accumulation in PDR by using the correction by Wi-Fi, and by limiting the use of Wi-Fi to the case where the RSS (Received Signal Strength) is large, we reduced the errors that occur from attenuation. We conducted three walking experiments to evaluate our proposed method. First, we estimated the reciprocating motion on a straight line by PDR. We confirmed that the azimuth angle and distance were estimated well. Next, we walked in an N-shaped route. In the estimation, the error accumulated and the estimated position gradually departed from the actual path by PDR. The error in the last position was reduced to 0.52 m, using our proposed method. Although the error was also accumulated by PDR when performing 3D moving, the error was corrected using the proposed method, and the average error reached 1.85 m, and the maximum error was reduced to 4.23 m. From these results, we conclude that our proposed method is efficient for navigation without any specialized preparation.
