  Elephant-human conflict (EHC) is one of the major problems in most African
and Asian countries. As humans overutilize natural resources for their
development, elephants' living area continues to decrease; this leads elephants
to invade the human living area and raid crops more frequently, costing
millions of dollars annually. To mitigate EHC, in this paper, we propose an
original solution that comprises of three parts: a compact custom low-power GPS
tag that is installed on the elephants, a receiver stationed in the human
living area that detects the elephants' presence near a farm, and an autonomous
unmanned aerial vehicle (UAV) system that tracks and herds the elephants away
from the farms. By utilizing proportional-integral-derivative controller and
machine learning algorithms, we obtain accurate tracking trajectories at a
real-time processing speed of 32 FPS. Our proposed autonomous system can save
over 68 % cost compared with human-controlled UAVs in mitigating EHC.
