ABSTRACT
Modern smartphones and location-based services and apps are poised to transform our daily life. However, smartphone-based localization solutions are limited mainly to the outdoors mostly missing practical, robust, and accurate indoor location solutions. This chapter provides an overview of location sensing systems and localization approaches. It proposes a practical and accurate solution that fills the long-lasting gap of smartphone-based indoor localization. Localization schemes can be classified into three categories of methods: angle-based, fingerprinting-based, and ranging-based. An angle-based approach relies on the directional antenna scan to achieve angle resolution. Fingerprinting-based approaches or other proximity approaches feature lowest complexity without any requirement for additional infrastructure. A ranging-based approach is more straightforward. Measuring the radio signal strength (RSS) and time-of-arrival (TOA) are the two typical ranging solutions. Compared with TOA, RSS information is widely available and lots of work has been dedicated to using the RSS of WiFi, Bluetooth, or cellular signals, for indoor localization.
