The fingerprint-based approach for positioning in WLAN has been drawing great attention these days. However, the approach usually requires tremendous time and efforts to collect location fingerprints for the target area. In this paper, we propose an interpolation method based on Voronoi tessellation to significantly reduce such calibration efforts and to improve accuracy. Unlike other interpolation methods, our method refines the propagation model for each cell of the target area tessellated by a higher-order Voronoi diagram. Consequently, our method can take into account the signal fading caused by walls and obstacles more accurately. The proposed method significantly outperformed other interpolation methods in accuracy. View full abstract»

Context-aware applications become more and more popular in today's life. Location-aware information has derived a lot of research issues. This paper presents a precise indoor RF-based WLAN (IEEE 802.11) locating system named precise indoor locating system (PILS). Most proposed location systems acquire well location estimation results but consume high level of manual effort to collect a huge amount of signal data. As a consequence, the system becomes impractical and manpower-wasted. In this paper, we aim to reduce the manual effort in constructing radio map and maintain high accuracy in our system. We propose models for data calibration, interpolating, and location estimation in PILS. In data calibration and location estimation models, we consider of autocorrelation of signal samples to enhance the accuracy. Wireless channel propagation model is also in our concern. Large scale and small scale fading are involved in the wireless channel propagation. View full abstract»

As mobile computing technology becomes more and more mature, people feel great interest on context-aware applications and services. Referring to context, location-aware system is one of the most important components. This paper presents a precise indoor RF-based (IEEE 802.11) locating system named precise indoor locating system (PILS). In order to acquire high level of location estimation result, a large number of training samples should be collected in offline phase. As a result, the system becomes impractical and huge number of man-power is needed. In this paper, we aim to reduce the manual effort in constructing radio map and maintain high accuracy in our system. We propose models for data calibration, interpolating, location estimation, and tracking in PILS. Wireless Channel Propagation model is also in our concern. Large scale and small scale fading are involved in the wireless channel propagation View full abstract»