Automatic Vehicle Location

Automatic vehicle location (AVL or ~locating; telelocating in EU) is a means for automatically determining and transmitting the geographic location of a vehicle. This vehicle location data, from one or more vehicles, may then be collected by a vehicle tracking system to manage an overview of vehicle travel. As of 2017, GPS technology has reached the point of having the transmitting device be smaller than the size of a human thumb (thus easier to conceal), able to run 6 months or more between battery charges, easy to communicate with smartphones (merely requiring a duplicate SIM card from one's mobile phone carrier in most cases) — all for less than $20 USD. Most commonly, the location is determined using GPS and the transmission mechanism is SMS, GPRS, or a satellite or terrestrial radio from the vehicle to a radio receiver. A single antenna unit covering all the needed frequency bands can be employed. GSM and EVDO are the most common services applied, because of the low data rate needed for AVL, and the low cost and near-ubiquitous nature of these public networks. The low bandwidth requirements also allow for satellite technology to receive telemetry data at a moderately higher cost, but across a global coverage area and into very remote locations not covered well by terrestrial radio or public carriers. Other options for determining actual location, for example in environments where GPS illumination is poor, are dead reckoning, i.e. inertial navigation, or active RFID systems or cooperative RTLS systems. These systems may be applied in combination in some cases. In addition, terrestrial radio positioning systems using a low frequency switched packet radio network have also been used as an alternative to GPS based systems. Automatic vehicle locating is a powerful tool for managing fleets of vehicles such as service vehicles, emergency vehicles, and public transport vehicles such as buses and trains. It is also used to track mobile assets, such as non wheeled construction equipment, non motorized trailers, and mobile power generators.