What is GPS Tracking?
A GPS Tracking unit is a device, normally carried by a moving vehicle or person, that uses the Global Positioning System to determine and track its precise location.
What is Tracking Device Technology?
Given the speed of light and where and when the signal was sent, the GPS receiver calculates where on earth your car, PND, hiker's GPS, or smartphone is. It takes three GPS signals to determine (triangulate) the receiver's position and a fourth to also calculate altitude.