One of the fast-growing GPS applications is vehicle tracking. GPS-equipped fleet vehicles, public transportation systems, delivery trucks, and courier services use receivers to monitor their locations at all times. Public safety services, police, fire, and emergency medical services, are using GPS receivers to determine the nearest service vehicle to an emergency, enabling the quickest response in critical situations.
Automatic Vehicle Location (AVL) is a technologically advanced method of remote vehicle tracking and monitoring using GPS. Each vehicle is equipped with a module that receives signals from a series of satellites, and calculates its current geographical location, speed, and heading. This information can be stored for later retrieval or, frequently, transmitted to a central dispatch/control location where it is displayed on a high-resolution geographical map.
Most users think of GPS as a means of determining position, but the constellation of 24 satellites is also an excellent timekeeper.