Novel Positioning System for Mobile Robot Using RFID Power Control

This research proposes a method which can be applied into location recognition of mobile robots using patterns and the numbers of recognized tags. As passive RFID tags can only measure existence of tags that are located in a recognizable range of a RFID reader, the physical position of each tag cannot be measured; thus, in order to receive information about positions of tags, a proper method to measure the positions should be selected. Also, in a real environment, results differ from ideal results based on characteristics of antennas and surrounding environments, characteristics of tags. Thus, this paper discusses a method to estimate locations according to values of power control with passive RFID tags in a real environment. In an experiment, a UHF-900MHz RFID reader was utilized with placement of passive RFID tags on a floor; the power of the reader was controlled with 30 different levels. In this paper, the differences according to the levels will be discussed with details. This research can be applied to location recognition with RFID power control in a real environment.