Wireless indoor positioning system for the visually impaired

The paper presents a prototype radio network aiding the visually impaired to navigate in indoor areas. The main purpose of the system is to provide accurate and reliable location information as well as to enable access to location related context information. The nodes of the network operate in two modes providing basis for both rough and precise user position estimation. The data transmitted by the nodes are used to get access to additional services, e.g. to retrieve position related context information.