RFID-based indoor positioning technologies - where are we?

Radio frequency identification (RFID) is an emerging technology that forms an essential part of ubiquitous positioning. For many years, it has been predominantly employed for tracking goods in supply chains. Recently, its usages have rapidly extended into manufacturing, defence, retail and many other application fields, for the purposes of people identification, suppliers monitoring and payment processing etc. RFID has been regarded as a core technology for indoor positioning due to its capability of wireless communication. However, the development and implementation of RFID technology has been so fast nowadays that the assessment of the techniques could hardly keep up with the pace of technical evolution. This paper presents an overview of various state-of-the-art RFID techniques and applications, with specific relevance to the field of indoor positioning. The latest performance parameters and advanced characteristics of the technology such as the ranging capability, system miniaturisation and robust multi-sensor integration are investigated, and selected novel applications and the future trends of RFID-based indoor positioning techniques are also discussed The results will be beneficial for researchers, industrial and other end users to better understand and innovatively use the technology.