Besides mobile devices, the enhancement of everyday objects plays a major role when design future environments. These objects usually do not have any processing capabilities or network connectivity. To actively integrate them into the environment the identification of these objects is fundamental. Accurate tracking is in most cases secondary, since the interaction possibilities are restricted by their lacking computational capabilities. Although absolute location information is not required in most applications, the proximity to other, mostly IT-enhanced, artefacts is often a useful information.
To fulfill these requirements, a combination of passive and active RFID-systems seems to be feasible and affordable approach. While most passive systems can only identify tagged objects, some active RFID systems are able to measure the received signal strength. If signal strength measurement is possible at several antennas, the location of the transponder can be calculated using triangulation.