The Mixed Floor Localization System Based On Barometer And WiFi

With the high-speed development of smart phones and mobile network, location services has become an indispensable part of People's daily life. As an important supporting technology, floor localization in multi-floor buildings plays significant roles in many indoor Location Based Service (LBS) applications such as the fire emergency response and the floor-based precise advertising.While the research of floor localization is in its infancy stage, the majority of fingerprint-based floor localization approaches suffer from the labor-intensive and time-consuming site-survey, not device-free and the low localization accuracy. Barometer-based floor localization is another promising direction due to the increasing availability of the barometer sensor-equipped smartphones.After reviewed the little research about floor localization field, this paper is the first floor localization work that exploits the combination of Wi-Fi RSS and barometric pressure for accurate floor localization. In this paper, the main work and contributions are as follows:(1) To the best of our knowledge, this is the first floor localization approach based on the combination of WiFi RSS and barometer values, which needs only few percentages of total smartphones that users carry equipped with barometer sensors.(2) Using crowdsourcing, BarFi eliminates the need of war-driving of site-survey and prior knowledge about both the Wi-Fi infrastructure and the floor plans of buildings.(3) The key novelty of BarFi is a two-phase clustering method proposed to train the RSS fingerprint floor map with the aid of barometer, which consists of a barometer-based hierarchical clustering phase and a Wi-Fi-based K-Means clustering phase.(4) The real-world evaluation shows BarFi achieves satisfying performance that its accuracy reaches 96.3% when the proportion of smartphones equipped with barometer sensors is 12% out of the total.