US Patent 6903682 DGPS animal containment system

An animal containment system includes a receiver unit carried by the animal. The receiver unit includes a GPS receiver for receiving satellite data; a memory for storing a plurality of waypoints defining a boundary, a stimulation circuit; and a processor coupled with the GPS receiver and the stimulation circuit. The processor activates the stimulation circuit at a distance from the boundary when the animal is within the boundary, dependent upon animal positional variables, and deactivates the stimulation circuit when the animal is outside the boundary.