RSSI Assisted Data-Compensation Positioning Algorithm In Rfid System

This thesis presented a positioning algorithm named Received Signal Strength Indicator(RSSI) Assisted Data Compensation Positioning Algorithm(RADCP) through analyzing the wireless positioning demand in security area, then implemented and applied the algorithm in a security positioning and monitoring management based RFID system developed independently.The process of the RADCP algorithm is divided into three stages:(1) data preprocessing,the parameter of the Radio Propagation Model is compensated by Partial Least Squares(PLS)which is one of the data-compensation methods in this thesis;(2) RSSI assisted ranging, the distance between the readers and the RFID location tags is obtained by combining the model which was computed in the data preprocessing stage in this thesis;(3) obtain position coordinate of the RFID location tags, the position coordinate of the RFID location tags is obtained by using Circle Positioning Model(CPM).The RADCP algorithm is applied in the security positioning and monitoring management system. This system is deployed on the PC. The data source of the system is provided by the lower machines(the RFID readers and location tags). The data uploaded by the lower machines is processed by PC. The communication between PC and the lower machines is implemented by using TCP protocol through WIFI. This system is divided by its function into positioning data management subsystem and positioning and monitoring management subsystem. The RFID based positioning data management subsystem is mainly used to receive and store data that uploaded from the lower machines. The positioning and monitoring management subsystem based on RFID used the data that store from data management subsystem as a data source. The positioning and monitoring management subsystem provided functions such as real-time location monitoring, history position information querying, history exception information querying, database backup and recovering, extraordinary alarm etc.Test results show that: the average positioning accuracy of RADCP algorithm improved37.4% and 32.7% compared to triangular method and centroid algorithm, and its' execution time recuded 57.6% and 61.3% compared to triangular method and centroid algorithm; the system can catch exceptions and alarm intime, has a better real-time and intuitive, meets the design target.