Automatic vehicle rental ( AVL or ~ locating ; telelocating in EU) is a means for automatically determining and transmitting the geographic location of a vehicle . This 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, and is able to run 6 months or more between battery chargings, easy to communicate with smartphones Requiring a duplicate SIM card from a mobile phone carrier in most cases) and 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 necessary 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 the entire coverage area by terrestrial radio or public carriers. Other options for determining actual location, For example in environments where GPS is illuminating is poor, are dead reckoning , ie 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 locator is a powerful tool for managing fleets of 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.
Another purpose of tracking is to provide a large driver and crewing staff. For example, suppose an ambulance fleet has an. Using an AVL system to evaluate the location of the vehicle in the service of the vehicle. 
Types of systems
Simple direction finding
Amateur Radio and Some cellular or PCS wireless systems use the direction finding or triangulation of transmitter signals radiated by the mobile. This is sometimes referred to as radio direction finding or RDF . The simplest forms of these systems calculate the bearing from two fixed sites to the mobile. This creates a triangle with endpoints at the two fixed points and the mobile. Trigonometry tells you roughly where the mobile transmitter is located. In wireless telephone systems, the phones transmit continually when off-hook, making continuous tracking and the collection of many possible samples.
Former LORAN-based locating
Motorola offered a 1970s-era system based on the United States Coast Guard LORAN maritime navigation system. The LORAN system was intended for ships but signal levels on the US east- and west-coast areas were adequate for use with receivers in automobiles. The system may have been marketed under the Motorola model name Metricom . It consisted of an LF LAN receiver and data interface box / modem connected to a separate two-way radio. The receiver and interface calculated at latitude and longitude in degrees, decimal degrees based on the LORAN signals. This MDC-1200 or MDC-4800 is a high-quality, high-quality, high-performance, high- The system works reliably but sometimes problems with electrical noise in urban areas. Sparking electric trolley poles or industrial plants, which radiate electrical noise from somewhere overwhelmed the LORAN signals, affecting the system’s ability to determine the mobile’s geolocation. Because of the limited resolution, this type of system was impractical for small communities or operational areas.
To track and locate vehicles along fixed routes, a technology called Expired Signpost transmitters is employed. This is used on transit routes and rail lines where the vehicles are tracked continuously on the same linear route. A transponder or RFID chip along the road . As each transponder was passed, the moving vehicle would receive and receive an ack , or handshake, from the signpost transmitter. A transmitter on the mobile would carry passing the signal to a system controller. This call supervision, a call center , Or a dispatch center to monitor the progress of the vehicle and whether or not the vehicle was on schedule . These systems are an alternative in tunnels or other conveyances where GPS signals are blocked by terrain. 
Today’s GPS-based locating
The low price and ubiquity of Global Positioning System or GPS equipment has made it more accurate and reliable telelocation systems. GPS signals are impervious to most electrical noise sources and require the user to install an entire system. Usually only one receiver to collect signals from the satellite segment is installed in each vehicle.
Large private telelocation or AVL systems, a radio-backbone. These systems are used for businesses like parcel delivery and ambulances. Smaller systems which do not justify building a separate radio system use cellular or PCS data services to communicate their data from their dispatching centers. Location data is periodically polled from each vehicle in a fleet by a central controller or computer. In the simplest systems, data from the GPS receiver is displayed on a map allowing humans to determine the location of each vehicle. More complex systems feed the data into a computer assisted dispatch system which automates the process. For example, The computer assisted dispatch system may check the location of a call for service and then pick up a list of the closest ambulances. This narrows the dispatcher’s choice of the four vehicles.
Some wireless carriers such as Nextel have decided GPS was the best way to provide the 9-1-1 Enhanced security. Newer Nextel radios have embedded GPS receivers which are polled if 9-1-1 is dialed. The 9-1-1 satellite receiver is latitude and longitude. In the case of a computer system, the system can be configured as a computer system.
The main purpose of using AVL is not only to locate the vehicles, but also to obtain information about engine data, fuel consumption, driver data and sensor data from the doors, freezer room on trucks or air pressure. Such data can be obtained via the CAN-bus , via direct connections to AVL systems or via open bus systems such as UFDEX which both sends and receives data via SMS or GPRS in pure ASCII text format. Because MOST AVL Consists of two parts, GPS and GSM modem with additional embedded AVL software contained in a microcontroller , Most AVL systems are fixed for ict Purposes UNLESS They connect to an open bus system for expansion possibilities.
With an open bus system the users can send invoices based on real-time data, where RFID or barcode readers can make a fairly good automated system to avoid human errors.
Gasoline and fuel oil. 
Another scenario for sensor functions is to connect the AVL to driver information, to collect data about driving time, stops, or even driver absence from the vehicle. If the driver / worker conditions is such as the hourly rates for driving and working outside the same, this can be monitored by sensors, using iButton or other personal identification devices. Later by analyzing log-file it is possible to get reports on any kind of events, like stops, visited streets, speed limits violations, etc. 
Differentiating between Automatic Vehicle Rental and Events Activated Tracking Systems
It might be a good idea to draw a distinction between vehicle rental systems which track automatically and eventually triggered by an event. There is increasingly crossover between the different systems and those with experience of this sector will be able to draw on a number of examples which break the rule.
AVL (Automatic Vehicle Location) This type of vehicle tracking is normally used in the fleet or driver management sector. The unit is configured to automatically transmit its location at a set time interval, eg every 5 minutes. The unit is activated when the ignition is switched on / off.
EATS (Events Activated Tracking System) This type of system is used in conjunction with security solutions. If, for example, a thief breaks into a steal it, the tracking system can be triggered by the immobilizer unit or motion sensor being activated. A monitoring office, will then be automatically notified that the unit has been activated and begin tracking the vehicle.
Some AVL and EATS technologies. However, there is a tendency towards a separation of these functions. It is worth taking note that vehicle tracking products tends to fall into one, not both of the technologies.
AVL technology is predominately used when it comes to driver tracking solutions. The use of Automatic Vehicle Rental is given in the following scenario; A car breaks down by the side of the road and the occupant calls a vehicle recovery company. The vehicle recovery company has several vehicles operating in the area. This is a very good job. It is a very good job. If you were to incorporate the other aspects of vehicle telematics into this scenario; The dispatcher, or rather the phoning the recovery vehicle operative, could transmit the job directly to the operative’s mobile data device, who would then use the satellite to navigate his day to the job.
EATS technology is predominately used when applying vehicle tracking to vehicle security solutions. An example of this distinction is given in the following scenario; A building company that owns some parts of plant machinery that are regularly left unattended, at weekends, on building sites. Thieves is one of the most popular and most popular in the world. Typically the ignition would not have to be turned on and so the AVL products would not typically be activated. GeoFence alarm event, would be activated.
Both AVL and EATS systems track, but often for different purposes.
Special applications of automatic vehicle locating
Vehicle rental technologies can be used in the following scenarios:
- Fleet management : when managing a fleet of vehicles, knowing the real-time location of all the drivers to meet customer needs more efficiently. Vehicle rental information can also be used to verify that legal requirements are being met: for example, that drivers are taking rest breaks and obeying speed limits.
- Passenger Information: Real-time passenger information systems use predictions based on AVL input to the expected arrival and departure times of public transport services.
- Asset tracking : Asset tracking : Asset tracking : Asset tracking . For example, haulage and logistics companies often operate trucks with detachable load carrying units. In this case, trailers can be tracked independently of the cabs used to drive them. Combining vehicle rental with inventory management which can be used to reconcile which item is currently on which vehicle can be used to determine physical location down to the level of individual packages.
- Field worker management: companies with a field service or sales workforce can use information from vehicle tracking systems to plan field workers.
- Covert surveillance: vehicle rental devices
- Automatic number plate
- Fleet telematics
- GPS tracking
- Intelligent transportation system
- Mobile phone tracking
- NextBus , an implementation used for public transportation systems
- OnStar , vehicle manufacturer implemented tracking systems.
- Tracking system
- Vehicle Infrastructure Integration
- Vehicle tracking system
- Jump up^ One definition of AVL exists in, “Glossary,”Arizona Phase II Final Report: Statewide Radio Interoperability Needs Assessment,Macro Corporation and The State of Arizona, 2004, pp. 165.
- Jump up^ For an example of one US signpost system, see ict service manual:T1919A Metrocom II 150.8-174 MHz Receiver Vehicle Location(Schaumburg, Illinois: Motorola Communications and Electronics, 1979).
- Jump up^ http://www.rfidsb.com/tm/2008/04/24/fuel-theft-in-the-usa-reaches-8-billion-in-2008/
- Jump up^ http://gurtam.com/en/docs/user-guide/new:tables