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Active RFID (Radio Frequency Identification) can be used also for position determination, although the system was not only developed for positioning and tracking but mainly for identification of objects. Using RFID in positioning, different approaches can be distinguished, i.e., cell-based positioning if the RFID tags are installed at active landmarks (i.e., known locations) in the surroundings, trilateration if ranges to the RFID tags are deducted from received signal strength (RSS in RFID terms) values and location fingerprinting where the measured signal power levels are used directly to obtain a position fix.
RFID cards readers