Experiences with performance tradeoffs in practical, continuous indoor localization

This paper describes our experiences and observations with a localization system that continuously tracks the indoor location of a large number of consumer mobile devices. Unlike past work that focuses principally on the accuracy of the location tracking algorithm, we study the performance of the localization system in terms of key additional metrics: scalability and energy-efficiency, which can sometimes conflict with the desire for high accuracy. To ensure that our solution can handle both Android and iOS-based mobile devices (& other closed mobile platforms), we adapt the conventional client-side fingerprinting-based localization approaches to develop a novel and practical infrastructure-based location tracking strategy. We study the relative accuracy to the two approaches in two different types of indoor buildings. Our studies establish how the building and its occupancy characteristics affect the accuracy achievable by different algorithms, and provide insights into why scalable, energy efficient and accurate indoor location tracking remains a challenge in practice.