Analysis and status quo of smartphone-based indoor localization systems

Over the past decade, indoor localization has been a topic of interest for both the academic and industrial communities. The need for location estimation, fueled mainly by inaccuracies of GPS indoors, has been addressed by specifically designed systems achieving a high localization accuracy but with a high deployment cost. Lately, dedicated systems are being replaced by smartphones through intelligent use of the built-in sensors. For instance, an accelerometer that can detect user activity can be combined with a wireless radio that captures wireless signal strength information to locate a user. With the advent of such technology, a myriad of systems have been proposed in the literature presenting an indefinite picture to a reader as to which systems actually work and which do not given practical considerations. This article takes up the goal of surveying state-of-the-art smartphone based indoor localization systems with critical analysis on their properties such as accuracies across various sensor designs, energy consumption and computational cost, user satisfaction and so on, thereby providing a status quo of such systems.