An implementation of positioning system in indoor environment based on active RFID

The Radio Frequency Identification (RFID) positioning based on the signal strength is the well know and feasible method. But the researches based on signal strength only usually make unsatisfied positioning error because of the instable of RFID signal. In this paper, we propose an indoor RFID positioning system which is based on the analysis of signal strength, the layout of sensing region, and the tracks of users. Different from the other RFID positioning systems, we use only one RFID reader with user, and the tags are layout in the positioning area systematically. The system integrates two phase work of positioning: analysis of signal strength in overlapping sensing area (Level 1), and analysis of users' movement directions with signal comparison (Level 2). The experiments show that the proposed mechanism improves the accuracy of positioning successfully.