SMART: Simultaneous indoor localization and map construction using smartphones

In recent years, we have witnessed a gold rush of location based services enabled by location awareness and persistent Internet connections of modern smartphones. However, the poor performance of indoor localization remains an obstacle to providing these services effectively inside buildings. Obtaining a comprehensive database of points of interest and high quality indoor maps is another obstacle because extensive human involvement is usually required for such tasks. In this paper, we propose a novel system SMART (Simultaneous Map Acquisition and Repeated Tracking) to address both problems. By tracking a subject based on sensor inputs and radio signals and detecting environmental fingerprints, SMART achieves simultaneous indoor localization and environment map construction using smartphones based on radio signals from surrounding WiFi access points and their own measured motion dynamics. Simulation results show that SMART outperforms a dead reckoning method by approximately 9 times in localization accuracy and constructs environment maps of 89% accuracy on average. SMART is robust against sensing errors and can automatically adapt to environment changes.