Advanced boundary virtual reference algorithm for an indoor system using an active RFID interrogator and transponder

摘要

Localization of persons and objects has become a necessity in many industrial services. In indoor circumstances, radio frequency identification (RFID) has superior performance. However, radio signals within indoor environments are generally weak, and the tags have very restricted abilities. In addition, the multipath propagation, total cost, and signal interference increase with increasing number of reference tags over a certain limit. Therefore, to improve the performance of indoor positioning for real-time localization, a new active acquisition method for an active RFID system that works at 2.4 GHz has been proposed; it is called the boundary virtual reference (BVIRE) algorithm. It depends on boundary virtual reference tags rather than increasing the number of real reference tags, which in turn reduces the total cost while maintaining the location accuracy. We have implemented a linear regression method to further enhance the positioning accuracy while eliminating the unnecessary tags from the estimation method using event filtering, in which only a few neighbouring reference tags are helpful in deciding the location of the object tag. The experimental results show that our BVIRE algorithm considerably reduces the error estimation compared with previous algorithms. The system has enhanced the positioning accuracy and lowered the total costs. In addition, the localization precision of the proposed approach has been significantly increased to approximately 90.25 % compared with PinPoint algorithm with no additional reference tags or radio frequency interference; this represents a significant improvement over other algorithms.