Localization of Passive RFID Tags by Small Cartesian Robot

In this paper simple localization method is proposed which uses radio-frequency identification (RFID) system working with low frequencies. The position of RFID tag is obtained by the recognition system installed on a small cartesian robot. In the robot head a RFID reader is installed. It was assumed that the used components for localization should be inexpensive. In the localization the inversion of the typical method based on proximity is applied. The difference is that the position of moving reader is not examined by tags, but position of tags is recognized by moving reader. The method was able to obtain precision in a range of a few millimeters. Two variants of collecting detection points and two variants of calculating position were examined. It was examined how the distance between the reader and the tag influences on position error, and what is the influence of head velocity on the detection accuracy.