A Systematic Survey and Comparative Analysis of Angular-Based Indoor Localization and Positioning Technologies

Angle-of-Arrival (AoA), as well as Angle-of-Departure (AoD) localization are general principles for performing localization based on angular measurements. In recent years, these principles have been gaining interest over more traditional techniques in the field of indoor localization and positioning. In contrast to Time-of-Arrival (ToA) and Time Difference of Arrival (TDoA)-based localization, AoA may do so without requiring a high number of anchor nodes or effective synchronization between them, with the trade-off of higher hardware and algorithmic complexity. Research on angular-based localization encompasses a wide range of technologies, each with its own advantages and disadvantages for dealing with the generally more complex propagation channels of indoor environments, as opposed to those in outdoor settings. In this contribution, we perform a systematic survey and meta analysis of the field of angularbased indoor localization systems, covering the technologies: Acoustic Positioning, Wi-Fi, Bluetooth, Ultra-Wideband (UWB), Light-based Positioning, Positioning in Cellular Networks (like 5G), mmWave, Terahertz-band Localization, Radio Frequency Identification (RFID), and RADAR. The research and literature on algorithms are examined as well. Furthermore, a new set of design considerations for angular-based localization systems is proposed, as well as several trade-offs between technologies, are discussed, and future research directions presented. Since angular-based localization is expected to play a key role in the future of indoor localization, this contribution provides a structure for researchers, as well as practitioners, to find a unified perspective on the topic.