Automatic Vehicle Locator (AVL) is a means

of determining the geographic location of a

vehicle and transmitting this info to a point

where it can be stored & used with certain

software and database applications.

AVL systems provide real time vehicle

tracking by integrating GPS(Global

Positioning System) , wireless communication

and GIS(Geo. Info system) mapping software.

The actual real-time position of each vehicle

is determined and relayed to control centre.

The Global Positioning System (GPS) is a

space-based satellite navigation system that

provides location and time information in all

weather conditions , anywhere on or near

the earth where there is an unobstructed

line of sight to four or more GPS satellites.

The Geographic Information System (GIS) is a

system designed to capture , store ,

manipulate , analyze , manage ,and present

all types of geographical data.

The GPS project was developed in 1973 to

overcome the limitations of previous

navigation systems.

Previous navigation systems did not give

accurate results.

They were not trust worthy.

Gradually , with the advancement in

technology , GPS was developed.

GSM (Global System for Mobile

Communications), is a standard developed

to describe protocols for second generation

2G digital cellular networks used by mobile

phones .

Enhanced Voice-Data Optimized or

Enhanced Voice-Data Only (EV-DO, EV,

EVDO, etc.) is a telecommunications

standard for the wireless transmission of

data through radio signals, typically for

broadband Internet access.

Trilateration :Imagine you are standing

somewhere on Earth with three satellites in

the sky above you. If you know how far away

you are from satellite A, then you know you

must be located somewhere on the red

circle. If you do the same for satellites B and

C, you can work out your location by seeing

where the three circles intersect. This is just

what your GPS receiver does, although it

uses overlapping spheres rather than circles.

AVL TECHNOLOGY

1) • Radio Receiver

2) • GPS Receiver

3) • GPS Modem

4) • Antenna

5) • GPS Base Station

6) • Wireless Communication

7) • GPS Tracking Software

8) • Data Stream Processing Servers

Radio receiver : a radio receiver is an electronic device that receives radio waves and converts the information carried by them to a usable form. It is used with an antenna

GPS receiver : A GPS receiver's job is to locate four or more of these satellites, figure out the distance to each, and use this information to deduce its own location.

GPS modem : A GSM modem is used to send the position of the vehicle from a remote place.

Antenna: An antenna (or aerial) is an electrical

device which converts electric power into radio

waves, and vice versa.

Base station : In a comp. network it is a

transceiver acting as a router for computers in

the network, possibly connecting them to a local

area network and/or the internet.

Wireless communication : Wireless

communication is the transfer of

information between two or more points that are

not connected by an electrical conductor.

GPS tracking : A GPS tracking unit is a device

that uses the Global Positioning System to

determine the precise location of a vehicle,

person, or other asset to which it is attached

and to record the position of the asset at

regular intervals.

Processing : The goal of complex event

processing is to identify meaningful events

(such as threats)and respond to them as

quickly as possible.

The satellites are synchronized to emit encoded

navigational information (exact positioning and

exact time).

Any vehicle equipped with a GPS receiver will

intercept these transmissions.

Using a simple mathematical formula derived from

triangulation, the receiver is able to calculate its

own longitude, latitude, velocity and even altitude.

Then this information is transmitted to a central

dispatch center.

In navigation, dead reckoning (also ded (for deduced) reckoning or DR) is the process of calculating one's current position by using a previously determined position, or fix, and advancing that position based upon known or estimated speeds over elapsed time and course.

Dead reckoning can give the best available information on position, but is subject to significant errors due to many factors as both speed and direction must be accurately known at all instants for position to be determined accurately.

DEAD-RECKONING:

Maps allow understandable view of vehicles

location and will also allow operators to apply

local knowledge.

Ionosphere and troposphere delays - The

satellite signal slows as it passes through the

atmosphere.

Signal multipath - The GPS signal is reflected off

objects such as tall buildings before it reaches the

receiver, thus increasing the travel time of the

signal.

Receiver clock errors - A receiver's built-in clock

is not as accurate as the atomic clocks onboard the

GPS satellites.

Fleet management: when managing a fleet

of vehicles, knowing the real-time location

of all drivers allows management to meet

customer needs more efficiently. Vehicle

location 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 show the expected arrival and departure

times of Public Transport services.

• Asset tracking : companies needing to track

valuable assets for insurance or other monitoring

purposes can now plot the real-time asset location

on a map and closely monitor movement and

operating status.

•Field worker management: companies with a

field service or sales workforce can use information

from vehicle tracking systems to plan field workers'

time, schedule subsequent customer visits and be

able to operate these departments efficiently.

•Covert surveillance: vehicle location devices

attached covertly by law enforcement or espionage

organizations can be used to track journeys made by

individuals who are under surveillance

AVL Benefits:

The AVL system combines a positioning hardware, a communication platform that can be used to monitor and track a commuter transport in real time.

This enables the transport management centres to observe, collect, and analyze location information about a commuter vehicle in real time.

This data will give an agency the ability to make better and more informed decisions while also providing quicker response to emergencies.

The benefits to the passengers mean better on time performance and less waiting time at bus stops.

"Glossary," Arizona Phase II Final Report: State-wide Radio Interoperability Needs Assessment, Macro Corporation and The State of Arizona, 2004, pp. 165.

http://www.gpsworld.com/gpsworld/article/articleDetail

www.calccit.org.itsdecision/serv

Murphy, Curtiss. Believable Dead Reckoning for Networked Games. Published in Game Engine Gems 2, Lengyel, Eric. AK Peters, 2011, p 308-326

S. Vitebsky (17–21 March 2002). "Performance analysis of 3G-1X EV-DO high data rate system". IEEE Wireless Communications and Networking Conference. IEEE. pp. 389–395.