Towards Persistent Spatial Awareness: A Review of Pedestrian Dead Reckoning-Centric Indoor Positioning with Smartphones

Navigating to a destination using smartphones has recently become a primary way in people's daily lives. Positioning is the prerequisite condition before efficient path planning can be achieved. In urban environments, people can self-localize with the aid of the global navigation satellite system (GNSS). However, last-mile navigation is still a challenge for pedestrians as current indoor positioning techniques cannot provide an accurate position. For the past few years, many researchers in academia and industry have thrown themselves into smartphone-based indoor positioning. Various solutions have been proposed to enable accurate and reliable position solutions. Pedestrian dead reckoning (PDR) is a popular positioning method as it is self-contained and outperforms inertial navigation. Also, other information from sensor data features and infrastructures, such as radio frequency (RF), can ensure the positioning service. At present, there are various indoor positioning reviews available to summarize current techniques. However, they focus primarily on separate positioning methods rather than integration. This paper aims to comprehensively review PDR-centric indoor positioning using smartphones. It covers the basic concept of PDR and its integration with other information, examining both infrastructure-free and infrastructure-dependent approaches. Furthermore, this paper outlines key considerations for conducting a comprehensive comparative analysis of algorithm. Finally, the challenges and future research trends are given. This paper can help readers understand the features of different PDR-centric integrations. It also contributes to the design of more robust solutions to satisfy the ever-increasing demand for indoor positioning.