Monitoring of Cow Location in a Barn by an Open-Source, Low-Cost, Low-Energy Bluetooth Tag System

Indoor localization of dairy cows is important for cow behavior recognition and effective farm management. In this paper, we propose a low-cost system for low-accuracy cow localization based on the reception of signals sent by an acceleration measurement system using the Bluetooth Low Energy protocol. The system consists of low-cost tags and receiving stations. The tag specifications and the localization accuracy of the system were studied experimentally. The received signal strength propagation model and dependence on the tag orientation was studied in an open-space and a barn environment. Two experiments for the evaluation of localization accuracy were conducted with 35 and 19 cows for two days. The localization reference was achieved from feeding stations, a milking robot and videos of cows decoded manually. The localization accuracy (mean +/- standard deviation) was 3.27 +/- 2.11 m for the entire barn (10 x 40 m(2)) and 1.9 +/- 0.67 m for a smaller area (4 x 5 m(2)). The system can be used for recognizing long-distance walking, crowded areas in the barn, e.g., queues to milking robots, and cow's preferable locations. The estimated system cost was 500 + 20 x (cow number) euro for one barn. The system has open-access software and detailed instructions for its installation and usage.