Automatic Vehicle Location Systems (AVL) are a specialized category of tracking system.AVL is used in the tracking of mobile assets such as security vehicles, taxis, courier vans, and emergency service vehicles. The most common reasons for deployment of AVL are improved security, greater control over fleet operations and efficiency improvements in dispatching. Typical AVL fleet sizes range from 5 to 2000 vehicles.

Its a AVL/AVTS solution which can use both wireless and GSM/CDMA communication backbone. It is highly customisable according to user's requirement.

In Vehicle Hardware

Each vehicle is fitted with a tracking device that determines the position of the vehicle with an accuracy of between 1 and 100 meters (depending on the technology used). The basic position fix is normally obtained via the Global Positioning System (GPS) satellites.
Optionally the in-vehicle unit may provide messaging functionality. This is typically used in dispatch or e-mail applications.
Standard in-vehicle hardware operates outdoors where a reasonably clear view of the sky is available. It cannot operate in tunnels, covered carparks or in areas where the sky is obscured by tall buildings (referred to as the "urban canyon" problem). For applications where GPS coverage alone is inadequate the in-vehicle solution must be augmented by the use of Dead Reckoning (DR) hardware. This monitors the speed and direction of the vehicle so a location can be approximated if the GPS satellites are not visible.

Wireless Communications Networks

The choice of wireless communications network is application dependent. In some cases UHF/VHF radio is appropriate, in others trunked mobile radio, or cellular technologies (GSM) are better suited. For coverage where terrestrial networks are not available, satellite based technologies are the remaining options. Common satellite networks for use in tracking systems include Inmarsat, Qualcomm, AMSC, Orbcomm, Mobisat and Argos.

Tracking Base Station

A tracking base station consists of standard computing hardware and specialized tracking software. This software manages the fleet of mobile units and provides a graphic display of tracks on a map background. Analysis, Messaging and Dispatch tools are also provided by the Base Station.

Maps

Central to any tracking solution is the requirement for maps to act as a backdrop. The expense of licensing and/or producing maps are factors that are very much dependent on the application.
For example maps required for trucking fleets are often simple, requiring only arterial roads, whereas the maps for tracking emergency vehicles can be very detailed, including vast quantities of related data such as street numbers, hazardous depots, locations of fire equipment and inventories.

Database

The choice of database platform is dependent on the size of the tracking system. For small systems, a PC based database is appropriate. Larger customers require a database server either on Windows NT or Unix, and possibly replicated servers at remote sites.
Usually the database platform and operating systems are selected to allow integration with other Information Technology systems already in use within the company.

Other Features

AVL solutions may incorporate additional features related to automated dispatch, messaging or security.

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