Automatic Vehicle Location
Automatic vehicle location is a means for determining the location of a vehicle and transmitting this information to a point where it can be used.
Most commonly, the location is determined using GPS, and the transmission mechanism is a radio or cellular connection from the vehicle to a receiver or nearby cell tower. Some other possibilities for determining location, for example in environments where GPS is not usable, are dead reckoning, inertial navigation, or RFID readers; sometimes a combination of these methods can be used. The tracking data is then transmitted using any one of a variety of telemetry systems; GSM is one of the commonest technologies used for telemetry, because of the low data rate needed for AVL, and the low cost and near-ubiquitous nature of GSM networks.
Automatic vehicle location is a powerful tool for managing fleets of vehicles, from service vehicles, emergency vehicles, and construction equipment, to public transport vehicles (buses and trains).