The Research Of RFID Indoor Positioning Algorithm

The current location-sensing is becoming one of the most important characteristics and the pursuit of goal in many new areas (such as ubiquitous computing, mobile computing, etc.).People have great requirement of location-based services in many application scenarios. Radio Frequency Identification technology has many advantages, such as high precision, non-line of sight, strong anti-interference, high security, and it can identify high-speed movement of the tag and multiple tags in the same time. RFID is becoming the preferred technology for indoor positioning. This paper will research the indoor positioning algorithm based on RFID. Based on LANDMARC and its improved algorithms, proposes an adaptive self-correction positioning method that uses a correction value to correct the positioning result; for the calculated RSSI values of virtual reference tags problem, proposes a non-interpolated method; in the field of three-dimensional positioning of RFID, proposes a three-dimensional indoor positioning algorithm based on the reference tags.The research contents and results of this paper include the following aspects:(1) The research and optimization of the calculation methods of the correction value. For the unreasonable of calculating correction value in error self-correction method, proposes an adaptive self-correction positioning algorithm. It uses the minimum error generated by adaptive Kneighboring method for N times to recalculate the correction value. It improves the positioning accuracy.(2) The research and optimization of calculation methods of RSSI values of virtual reference tags. Because of the relationship between RSSI value of tag and the distance to the reader is not simple linear, which lead to the calculated RSSI value of virtual reference tag is inaccurate. Here changes the layout of the actual reference tags, and uses the signal propagation model to calculate RSSI values of virtual reference tags. It improves the positioning accuracy.(3) This paper proposes a three-dimensional indoor positioning algorithm based on the reference tags. The actual reference tags are placed on the ceiling and the floor in an arrangement rule. The algorithm chooses some reference tags that are near to the positioning tag, they will create two kinds of virtual reference tags to calculate the distance from the reader to the positioning tag. In the end, uses the multilateral localization method to calculate the coordinate of the positioning tag.In this paper, by the experimental comparison, verify that the proposed algorithms have higher accuracy.