UHF-RFID System for Real-Time Sheep Location in Sheepfold Environments

In this paper, a UHF-RFID reader system is developed for 2D localization of sheep in sheepfold environments. It is built on an innovative compact Electronically Steerable Parasitic Array Radiator (ESPAR) type antenna leveraging superdirectivity and signal processing algorithms that utilize the amplitude and phase of retro-modulated signals from tags for localization. Experimental validation of the RFID system achieved lamb localization with read ranges of five to six meters and positional accuracy of less than 1 meter in most cases.