GPS Tracking is the generic term used for telematics as applied to tracking vehicle movement using a GPS Tracker.
A GPS Tracker is an electronic device which has a GPS module capable of receiving signals from the GPS satellite constellation. The location of the tracker is calculated using triangulation. The location information along with some more calculated parameters like speed, direction, altitude etc are sent to a server application through the internet. The server application displays the location of the tracker on a map. This map is viewable through a client application by the user.
This is the mechanism of GPS based vehicle tracking.