Demonstration of a Realtime Active-Tag RFID, Java Based Indoor Localization System using Particle Filtering Kai Wendlandt, Kosawat Sukchaya, Patrick Robertson, Mohammed Khider, and Michael Angermann German Aerospace Center, Institute of Communications and Navigation, M¨ unchner Str. 20, 82234 Wessling, Germany kai.wendlandt;patrick.robertson;mohammed.khider;michael.angermann@dlr.de Abstract. To develop and demonstrate accurate indoor pedestrian nav- igation, we implemented a flexible location framework which is able to use various sensors as positioning sources. In the current setup, the main positioning data is derived from an active long range RFID system which collects RSS values from various RFID tags in the environment. The po- sition is calculated using particle filtering algorithms. The demonstration shows the real time tracking of a person on a remote visualization screen. Key words: Real time location demonstration, long range RFID sys- tem, particle filtering, received signal strength (RSS) 1 Introduction and Background Today’s mobile devices are capable of using multiple network access methods and they are able of executing custom applications. This pushes many new ap- plications in the area of mobile entertainment, games, communication and also personal navigation. There are numerous devices available, which use GPS for outdoor route finding with cars and even for cyclists and pedestrians. But this last group of users poses the most challenging problem to devices and software, because a pedestrian can walk in nearly every area - especially in the urban canyons of cities and in indoor scenarios. There, the satellite signal is either affected by strong multipath propagation or it is blocked completely. Possible applications for person localization range from security relevant indoor scenarios (watchmen, fire fighter) to office navigation and also leisure activities. For these difficult scenarios, additional sensors at the mobile device can help to increase the accuracy considerably. In our real time demo we show the use of active RFID technologies for in- door positioning. We use a client-server structure with a notebook as client and a separate server that processes and visualizes the measurements that arrive from the client. The measurements are collected via external hardware at the note- book and transferred to the server via any available wireless network (UMTS or