Robust Indoor Positioning With Lifelong Learning

Inertial tracking and navigation systems have been playing an increasingly important role in indoor tracking and navigation. They have the competitive advantage of leveraging not requiring expensive infrastructure-only existing smart mobile devices with embedded inertial measurement units. When aided with other sources of information, such as radio data from existing WiFi/BLE infrastructure, and environment constraints from floor plans or radio maps, they often report great performance of 0.5-2 m. Given the promising results, what is it that prevents the widespread adoption of this tracking solution? We argue that pedestrian dead reckoning (PDR) techniques are often evaluated in a specific context and are not mature enough to handle variations in user motion, device type, device placement, or environment. They typically use a number of parameters that require careful context-specific tuning, which is labor intensive and requires expert knowledge. In this paper, we propose two novel approaches to address these problems. Our first contribution is a robust PDR algorithm, which is based on general physics principles that underpin human motion and is by design robust to context changes. The second contribution is a novel way of interaction between the PDR and map matching layers based on the principle of lifelong learning. Unlike traditional approaches where information flows unidirectionally from the PDR to the map matching layer, we introduce a feedback loop that can be used to automatically tune the parameters of the PDR algorithm. This is not dissimilar to the way that people improve their navigation skills when they repeatedly visit the same environment. Extensive experiments in multiple sites, with a variety of users, devices, and device placements, show that the combination of a robust PDR with a lifelong learning tracker can achieve submeter accuracy with no user effort for parameter tuning.