Automatic Vehicle Location

Applications				to scale, RFID or barcode readers, can make a
Application with vehicles				fairly good automated system to avoid human
Automatic vehicle locating is a powerful concept				errors.
for managing fleets of vehicles, as service				Logbook functions
vehicles, emergency vehicles, and especially				Another scenario for sensor functions is to
precious construction equipment, also public				connect the AVL to driver information, to collect
transport vehicles (buses and trains). It is also				data about driving time, stops, or even driver
used to track mobile assets, such as non wheeled				absence from the vehicle. If the driver/worker
construction equipment, non motorized trailers,				conditions is such as the hourly rates for driving
and mobile power generators.				and working outside is not the same, this can be
Application with vehicle drivers and crews				monitored by sensors.[needs clarification]
The other purpose of tracking is to provide				Differentiating between Automatic Vehicle
graded service or to manage a large driver and				Location and Events Activated Tracking Systems
crewing staff effectively. For example, suppose				It might be helpful to draw a distinction between
an ambulance fleet has an objective of arriving at				vehicle location systems which track automatically
the location of a call for service within six minutes				and vehicle location systems which track when
of receiving the request. Using an AVL system				triggered by an event. There is increasingly
allows to evaluate the locations of all vehicles in				crossover between the different systems and
service with driver and other crew in order to				those with experience of this sector will be able
pick the vehicle that will most likely arrive at the				to draw on a number of examples which break
destination fastest, (meeting the service				the rule.
objective).				A.V.L (Automatic Vehicle Location) This type of
Types of systems				vehicle tracking is normally used in the fleet or
Configurations				driver management sector. The unit is configured
A typical AVL system would use terrestrial				to automatically transmit it location at a set time
wireless communications already installed and then				interval, e.g. every 5 minutes. The unit is activated
communicates simultaneously the locations of a				when the ignition is switched on/off.
vehicle to the manager of a fleet of vehicles.				E.A.T.S (Events Activated Tracking system) This
Simple direction finding				type of system is primarily used in connection
Amateur radio and some cellular or PCS wireless				with vehicle or driver security solutions. If, for
systems use direction finding or triangulation of				example a thief breaks into your car and
transmitter signals radiated by the mobile. This is				attempts to steal it, the tracking system can be
sometimes called radio direction finding or RDF.				triggered by the immobiliser unit or motion sensor
The simplest forms of these systems calculate				being activated. A monitoring bureau, will then be
the bearing from two fixed sites to the mobile.				automatically notified that the unit has been
This creates a triangle with endpoints at the two				activated and begin tracking the vehicle.
fixed points and the mobile. Trigonometry tells				Some products on the market are a hybrid of
you roughly where the mobile transmitter is				both AVL and EATS technology. However
located. In wireless telephone systems, the				industry practice has tended to lean towards a
phones transmit continually when off-hook,				separation of these functions. It is worth taking
making continual tracking and the collection of				note that vehicle tracking products tend to fall in
many location samples possible. This is one type				to one, not both of the technologies.
of location system required by Federal				AVL technology is predominately used when
Communications Commission Rules for wireless				applying vehicle tracking to fleet or driver
Enhanced 911.				management solutions. The use of Automatic
Former LORAN-based locating				Vehicle Location is given in the following scenario;
Motorola offered a 1970s-era system based on				A car breaks down by the side of the road and
the United States Coast Guard LORAN maritime				the occupant calls a vehicle recovery company.
navigation system. The LORAN system was				The vehicle recovery company has several
intended for ships but signal levels on the US east-				vehicles operating in the area. Without needing to
and west-coast areas were adequate for use				call each driver to check his location the
with receivers in automobiles. The system may				dispatcher can pinpoint the nearest recovery
have been marketed under the Motorola model				vehicle and assign it to the new job. If you were
name Metricom. It consisted of an LF LORAN				to incorporate the other aspects of vehicle
receiver and data interface box/modem				telematics into this scenario; the dispatcher, rather
connected to a separate two-way radio. The				than phoning the recovery vehicle operative, could
receiver and interface calculated a latitude and				transmit the job details directly to the operative
longitude in degrees, decimal degrees format				mobile data device, who would then use the
based on the LORAN signals. This was sent over				in-vehicle satellite navigation to aid his journey to
the radio as MDC-1200 or MDC-4800 data to a				the job.
system controller, which plotted the mobile's				EATS technology is predominately used when
approximate location on a map. The system				applying vehicle tracking to vehicle security
worked reliably but sometimes had problems with				solutions. An example of this distinction is given in
electrical noise in urban areas. Sparking electric				the following scenario; A construction company
trolleys or industrial plants which radiated electrical				owns some pieces of plant machinery that are
noise sometime overwhelmed the LORAN signals,				regularly left unattended, at weekends, on building
affecting the system's ability to determine the				sites. Thieves break onto one site and a piece
mobile's geolocation. Because of the limited				equipment, such as a digger, is loaded on the back
resolution, this type of system was impractical for				of a flat bed truck and then driven away.
small communities or operational areas such as a				Typically the ignition wouldn need to be turned on
pit mine or port.				and as such most of the AVL products available
Signpost systems				wouldn typically be activated. Only products that
To track and locate vehicles along fixed routes, a				included a unit that was activated by a motion
technology called Signpost transmitters is				sensor or GeoFence alarm event, would be
employed. This is used on transit routes and rail				activated.
lines where the vehicles to be tracked continually				Both AVL and EATS systems track, but often
operated on the same linear route. A transponder				for different purposes.
or RFID chip along the vehicle route would be				Special applications of automatic vehicle locating
polled as the train or bus traverses its route. As				Vehicle location technologies can be used in the
each transponder was passed, the moving vehicle				following scenarios:
would query and receive an ack, or handshake,				Fleet management: when managing a fleet of
from the signpost transmitter. A transmitter on				vehicles, knowing the real-time location of all
the mobile would report passing the signpost to a				drivers allows management to meet customer
system controller. This allows supervision, a call				needs more efficiently. Vehicle location information
center, or a dispatch center to monitor the				can also be used to verify that legal requirements
progress of the vehicle and assess whether or				are being met: for example, that drivers are
not the vehicle was on schedule. These systems				taking rest breaks and obeying speed limits.
are an alternative inside tunnels or other				Passenger Information: Real-time Passenger
conveyances where GPS signals are blocked by				information systems use predictions based on
terrain.				AVL input to show the expected arrival and
Today's GPS-based locating				departure times of Public Transport services.
The low price and ubiquity of Global Positioning				Asset tracking: companies needing to track
System or GPS equipment has lent itself to more				valuable assets for insurance or other monitoring
accurate and reliable telelocation systems. GPS				purposes can now plot the real-time asset location
signals are impervious to most electrical noise				on a map and closely monitor movement and
sources and don't require the user to install an				operating status. For example, haulage and
entire system. Only a receiver to collect signals				logistics companies often operate trucks with
from the satellite segment is installed in each				detachable load carrying units. In this case, trailers
vehicle and a radio to communicate the collected				can be tracked independently of the cabs used to
location data with a dispatch point.				drive them. Combining vehicle location with
Large private telelocation or AVL systems send				inventory management that can be used to
data from GPS receivers in vehicles to a dispatch				reconcile which item is currently on which vehicle
center over their private, user-owned radio				can be used to identify physical location down to
backbone. These systems are used for				the level of individual packages.
businesses like parcel delivery and ambulances.				Field worker management: companies with a field
Smaller systems which don't justify building a				service or sales workforce can use information
separate radio system use cellular or PCS data				from vehicle tracking systems to plan field
services to communicate location data from				workers' time, schedule subsequent customer
vehicles to their dispatching center. Location data				visits and be able to operate these departments
is periodically polled from each vehicle in a fleet by				efficiently.
a central controller or computer. In the simplest				Covert surveillance: vehicle location devices
systems, data from the GPS receiver is displayed				attached covertly by law enforcement or
on a map allowing humans to determine the				espionage organizations can be used to track
location of each vehicle. More complex systems				journeys made by individuals who are under
feed the data into a computer assisted dispatch				surveillance
system which automates the process. For				See also
example, the computer assisted dispatch system				Automatic number plate recognition
may check the location of a call for service and				Fleet telematics
then pick a list of the four closest ambulances.				GPS tracking
This narrows the dispatcher's choice from the				Intelligent transportation system
entire fleet to an easier choice of four vehicles.				LoJack
Some wireless carriers such as Nextel have				Millennium Plus
decided GPS was the best way to provide the				Mobile phone tracking
mandated location data for wireless Enhanced				NextBus, an implementation used for public
9-1-1. Newer Nextel radios have embedded GPS				transportation systems
receivers which are polled if 9-1-1 is dialed. The				OnStar, vehicle manufacturer implemented
9-1-1 center is provided with latitude and longitude				tracking systems.
from the radio's GPS receiver. In centers with				StarChase
computer assisted dispatch, the system may				Telematics
assign an address to the call based on these				Tracking system
coordinates or may project an icon depicting the				Vehicle Infrastructure Integration
caller's location onto a map of the area.				Vehicle Tracking
Sensor-augmented AVL				References
The main purpose of using AVL is not only to				^ Thirty second reference only is from
locate the vehicles, but also to obtain information				Assessment of the Denver Regional
about engine data, fuel consumption, driver data				Transportation District's Automatic Vehicle
and sensor data from i.e. doors, freezer room on				Location System, US Department of
trucks or air pressure. Such data can be obtained				Transportation.
via the CAN-bus, via direct connections to AVL				^ One definition of AVL exists in, "Glossary,"
systems or via open bus systems such as UFDEX				Arizona Phase II Final Report: Statewide Radio
that both sends and receives data via SMS or				Interoperability Needs Assessment, Macro
GPRS in pure ASCII text format. Because most				Corporation and The State of Arizona, 2004, pp.
AVL consists of two parts, GPS and GSM				165.
modem with additional embedded AVL software				^ For an example of one US signpost system,
contained in a microcontroller, most AVL systems				see its service manual: T1919A Metrocom II
are fixed for its purposes unless they connect to				150.8-174 MHz Vehicle Location Receiver,
an open bus system for expansion possibilities.				(Schaumburg, Illinois: Motorola Communications and
With an open bus system the users can send				Electronics, 1979).
invoices based on goods delivered with exact				^ Wright, Matthew. "What is Vehicle Tracking ?".
location, time and date data where if connected				Retrieved 2009-03-13.

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Automatic Vehicle Location

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