Monitoring user position in the GiraffPlus AAL environment

In Ambient Assisted Living scenarios, elderly people are supported by pervasive and smart environments in their daily mobility and activities, with which they interact by means of a variety of devices and services deployed in the house. These devices, in addition to their particular function, can provide useful context information about the user behavior. In this paper we propose an indoor localization technique that exploits the presence of commercially available devices in the GiraffPlus AAL environment. GiraffPlus is a EU funded project, running in several test sites across Europe, that combines social interaction and long-term monitoring to help people live independently. In this context, the proposed localization algorithm is able to provide the position information in terms of last room visited by the user improving considerably the reaction of a user's caregiver in emergency situations. This paper also aims at providing a performance characterization of the commercially available devices used in the GiraffPlus AAL environments. We prove that, in order to guarantee an high level of reliability, this kind of device show a considerable transmission delay that makes the localization process non-trivial.