by Rohit Patel a report on AVL.

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AUTOMATIC VEHICLE LOCATOR
A Seminar Report
Submitted by
ROHIT KUMAR PATEL
(Roll No. : 12EI39)
In partial fulfillment for the award of the degree
of
Bachelor of Technology
in
Electronics & Instrumentation Engineering
Department of Electronics & Instrumentation Engineering
MJP ROHILKHAND UNIVERSITY, BAREILLY
December, 2015

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ACKNOWLEDGEMENT
I owe a great many thanks to great many people who helped and supported me during the making
of this seminar presentation and its report.
My deepest thanks to Dr. Sanjeev Tyagi, (co-ordinator of our seminar) for providing proper
guidance. He has taken pain to go through the seminar and make necessary suggestions when
needed.
I also express our thanks to Mr. Yograj Singh Daksh, Head of the Electronics and Instrumentation
Engineering Department, IET MJP Rohilkhand University Bareilly, for extending his support.
ROHIT KUMAR PATEL
12EI39

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INTRODUCTION CHAPTER-1
A GPS receiver placed in a car can receive signals from these satellites and will calculate the exact
location of the car in terms of latitude and longitude. This data can be sent to owner’s computer
that can monitor the location. A GSM modem can be integrated into this project for providing
security and remote control. The current location of the car can be found out by sending an SMS.
The car can also be disabled by sending an SMS.
1.1 MOTIVATION
With the advent of satellite navigation systems like GPS (Global Position System), GLONASS
and Galileo etc., it has become possible to track the position of any object having such systems.
Concept of localizing or determining position of an object has been popular since ancient times.
Earlier voyagers used magnetic compass for navigation purposes. It gave information about the
directions with certain accuracy but localizing the position of object was still a distant reality.
Figure 1.1 Basic diagram for vehicle tracking system
Now the navigations systems are used at many places for example in cars, military, engineering
survey and the list goes on. The advent use of navigation can be combined with modern day

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wireless communication services to yield a very useful application. It can be used to send the
position of an object to a distant location. So it becomes possible to monitor the position of a
remote object.
This opens a wide door of possibilities for new and exciting applications. Surveillance, Vehicle
Location Information, Location Based Services can be provided with considerable ease. The
remote monitoring systems become all the more useful if we use brute computing capabilities of
monitoring stations to calculate various other parameters related to remote object. For example it
is possible to record the path taken by a remote object (call it path tracing), or for calculating speed
of the object over long period of time, or for sounding alarm when the object approaches restricted
regions. Hence it depends on monitoring stations what kind of services they want to implement.
So there can be innumerous applications for a tracking system, that the reason for implement the
AVL. Throughout the thesis the AVL system has been explained.
1.2 OVERVIEW OF PROJECT
The Automatic Vehicle Locating System can be broadly divided into two parts
 The remote object
 The monitoring station
The remote object is the object whose location is to be monitored. In this thesis considered it to be
a vehicle. The remote object should consist of some kind of navigation system, which would help
to localize the position of the object. Further it should also contain some form of communication
equipment, preferably wireless. And at last there must be some kind of controller which co -
ordinates the operation of the navigation systems and communication equipment.
Figure 1.2 The remote object
Similarly the monitoring station should be equipped with a communication equipment to receive
the location data from the remote object. Further the station must contain a computing device
which can calculate and interpret the location data and provide it to the user in a comprehensive
NAVIGATION
SYSTEM
CONTROLLER
COMMUNICATION
DEVICES

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manner. For example if the user wants the output on map then co-ordinates obtained or calculated
must be represented on map. Also note that monitoring station need not be 'fixed'. There is no
reason to place such a restriction, after all as long as communicating equipment of the remote
object and the monitoring stations are connected it doesn't matter where a monitoring station is lo
Figure 1.3 The monitoring station
1.3 IMPLEMENTATION SCHEME
Until now showing the blocks of AVL conceptually. But real physical implementation requires far
more complexity. To localize the position of the object we have decided to use GPS (Global
Positioning System). Further GPS provides many advantages over other navigation systems. Since
wireless communication between the remote object and monitoring station is desirable we need to
ensure a robust and secure connection mechanism..
Figure 1.4 Automatic Vehicle Locator setups
At the monitoring station, a GSM modem. The computing device for interpreting the received data
can be either a computer or MCU. It depends on whether we want portable or fixed monitoring
stations. Finally we have used LCD display to display the final result in a comprehensive format.
Although there is possibility to use either SMS or GPRS to transfer the remote object data, we
have decided to implement the system initially using the SMS. This is mainly because of bulk
SMS service is available at a low cost.
COMMUNICATI
ON EQUIPMENT
COMPUTING
DEVICE
OUTPUT

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GSM RECEIVER CHAPTER-2
Communication over wireless channel is particularly challenging. Wireless channel provides a
dynamic environment because of factors like large scale path loss, small scale fading effects, and
multipath propagation. This all leads to high (and variable) bit error rates. So many important
signal processing techniques like modulation, equalization, diversity and channel coding are used
to improve bit error rate. Also to make wireless communication secure, we need to employ some
form of encryption at some communication layer.
2.1 INTRODUCTION
GSM (Global System for Mobile Communication) are the standards given by ETSI (European
Telecommunication Standard Institute) for digital cellular networks. GSM provides a robust set of
protocols for communications. It has some very desirable features:
 Encryption algorithms for communication over air.
 Mobility management for providing high roaming capabilities.
 FEC (Forward Error Control) at lower layers of radio interface for combating and
correcting error.
 Transparent set of user-plane protocols provide freedom to user. So he can implement
vivid variety of applications using GSM Network without worrying of wireless
communication woes.
2.2 GSM KIT
GSM modems act as an access point for GSM networks. Many complexities of accessing a GSM
network are hidden by GSM modem. GSM modem provides a set of commands called AT
commands (AT stands for Attention) for accessing GSM service. The supported AT commands
and their format depends on the manufacturer of the modem. Another important point to note is
that GSM Modems provide a number of interfaces to access. However at the monitoring station
which may have a PC, we may go for modem with Bluetooth or USB interface, because RS-232
is no longer available on modern PC.
GSM receiver is used to receive the data from any user via the BTS. Today Mainly SIM900 module
is used for GSM system. This chapter describes the hardware interface of the SIM SIM900A

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module that connects to the specific application and the air interface. As SIM900A can be
integrated with a wide range of applications, all functional components of SIM900 are described
in detail as.
Fig: 2.1 GSM Module SIM900A
2.2.1 Product detail
SIM900A is a Tri-band GSM/GPRS engine that works on frequencies EGSM (Enhanced GSM
)900 MHz, DCS 1800 MHz and PCS1900 MHz, SIM900A provides GPRS multi-slot class 10
capability and support the GPRS coding schemes. The physical interface to the mobile application
is made through a 60 pins board-to-board connector.
 Two serial ports can help you easily develop your applications.
 Two audio channels include two microphones inputs and two speaker outputs.

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2.2.2 Application Interface
All hardware interfaces except RF interface that connects SIM900A to the customers’ cellular
application platform is through a 60-pin 0.5mm pitch board-to-board connector.
Sub-interfaces included in this board-to-board connector are described in detail in following
chapters-
 Power supply
 Dual serial interface
 Two analog audio interfaces
 SIM interface
 Indicators (Buzzer, LED)

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GPS SYSTEM CHAPTER 3
GPS (The full description is- Navigation System with Timing and Ranging Global Positioning
System, NAVSTAR-GPS) was developed by the U.S. department of defense (DoD) and can be
used both by civilians and military personal. There are currently 28 operational satellites orbiting
the earth at a height of 20,180km on 6 different orbital planes. Their orbits are inclined at 55 degree
to equator, ensuring that a least 4 satellites are in radio communication with any point on the planet.
Fig. 3.1 Smart GPS receiver
3.1 WHY GPS?
Basically, A GPS (Global positioning system) receiver determine just four variables, i.e, longitude,
latitude, height and time. Additional information (e.g. speed, direction etc,) can be derived from
these four components.
Using GPS the following value can be determine anywhere on the earth-
 One’s exact location, accurate to within a range of 20m to 1 mm.
 The precise time (UTC) accurate to within a range of 60ns to 5ns.

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Fig 3.2 GPS satellites orbit the Earth on 6 orbital planes
During the development of the GPS system, particular emphasis was placed on the following three
aspects:-
1. It had to provide users with the capability of determining position, speed and time, whether in
motion or at rest.
2. It had to have a continuous, global, 3 dimensional positioning capability with a high degree of
accuracy, Irrespective of the weather.
3. It had to offer potential for civilian use.
In order to calculate one’s exact position, all that needs to be measured is the signal transit time
between the point of observation and four different satellites whose positions are known.
3.2 DETERMINING A POSITION IN 3-D SPACE
In order to determine these four unknown variables, four independent equations are needed. The
four transit times required are supplied by the four different satellites (sat. 1 to sat. 4). The 28 GPS
satellites are distributed around the globe in such a way that at least 4 of them are always “visible”
from any point on Earth.

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FIG: 3.4 Four satellites are required to determine a position in 3-D space
3.3 THE GPS NAVIGATION MESSAGE
The navigation message is a continuous stream of data transmitted at 50 bits per second. Each
satellite relays the following information to Earth-
 System time and clock correction values.
 Its own highly accurate orbital data (ephemeris).
 Approximate orbital data for all other satellites (almanac).
3.4 DESCRIPTION OF THE ENTIRE SYSTEM
The Global Positioning System (GPS) comprises three segments:-
 The space segment (all functional satellites)
 The control segment (all ground stations involved in the monitoring of the system master
control station, monitor stations, and ground control stations).
 The user segment (all civil and military GPS users).

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FIG: 3.5 The three GPS segments
3.5 ACCURACY OF POSITION
Although originally intended for purely military purposes, the GPS system is used today primarily
for civil applications, such as surveying, navigation (air, sea and land), positioning, measuring
velocity, determining time, monitoring stationary and moving objects, etc. The system operator
guarantees the standard civilian user of the service that the following accuracy (Table 3.1) will be
attained for 95% of the time (2drms value).

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Table 3.1 Accuracy of the standard civilian service
HORIZONTAL
ACCURACY
VERTICAL ACCURACY HIGHT ACCURACY
≤13 m ≤22 m ~40ns
3.6 CALCULATING A POSITION
The principle of measuring signal transit time (evaluation of pseudo-range). In order for a GPS
receiver to determine its position, it has to receive time signals from four different satellites (Sat 1
... Sat 4), to enable it to calculate signal transit time Δt1 ... Δt4 (Figure 4.4).
Calculations are effected in a Cartesian, three-dimensional co-ordinate system with a geocentric
origin. As the locations X-Sat, Y-Sat and Z-Sat of the four satellites are known, the user co-
ordinates can be calculated.
Fig. 3.4 Four satellite signals must be received
Calculations are effected in a Cartesian, three-dimensional co-ordinate system with a geocentric
origin (Figure4.1). The range of the user from the four satellites R1, R2, R3 and R4 can be
determined with the help of signal transit times Δt1, Δt2, Δt3 and Δt4 between the four satellites
and the user. As the locations X-Sat, Y-Sat and Z-Sat of the four satellites are known, the user co-
ordinates can be calculated.

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ALGORITHM AND RESULTS CHAPTER-4
4.1 ALGORITHM
First of all GSM Modem must be registered to Network. If registration step is not successful then
the command should be again sent. If the registration is successful then signal quality is checked.
The obtained values are displayed on console itself. A counter is initialized with value 10 (this is
because GPS data is sent to control station at interval of 10 seconds). But note that data obtained
is shown on local console at normal rate of 1 sample per second. Once counter is set, data packets
from GPS receiver is received via USB driver interface. Fig 4.1 shows the flow diagram related to
this algorithm.
4.2 RESULTS
Figure 4.2 and Figure 4.3 shows the output data. Validity of this data was checked using Google
Maps. Also while testing the project it was observed that GPS data is accurate when used in
outdoors. This fact could be explained because in crowded places and indoors there could be
multiple path components causing problem. The longitude and latitude are shown in degree and
minutes multiplied by 100. Another point to note here is that number of satellites in view generally
depends on time of the day, and the location at which the remote object is. But user should not
worry about the number of satellites because 4 satellites are enough to calculate the exact
coordinates. Speed is shown in Nautical Miles per hour because this is defect in GPS receivers.
Height shown in the data are the measured from geodetic datum which could be approximated as
mean sea level for simple applications

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Fig 4.1 Algorithm

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Fig 4.2 screen shot of GPS value on monitor
Fig 4.3 value received GSM terminal

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4.3 APPLICATION
Using the Global Positioning System (GPS), a process used to establish apposition at any point on
the globe) the following two values can be determined anywhere on Earth.
 One’s exact location (longitude, latitude and height co-ordinates) accurate to within a
range of 20 m to approx.1mm.
 The precise time (world time, Universal Time Coordinated, UTC) accurate to within a
range of 60ns to approx.1ns. Various additional variables can be derived from the three-
dimensional position and the exact time, such as
 Speed
 Acceleration
 Course
 Local time
 Range instrument
By AVL (Automatic vehicle locator) we can track the exact position of any vehicle or moving
objects.
Fig 4.4 whole process of working.

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4.4 OTHER APPLICATION
1. Transport companies, logistics in general (aircraft, water-borne craft and road vehicle)
2. Railways
3. Geographical tachographs
4. Fleet management
5. Navigation systems
6. Military
7. Science and Research
GPS has readily found itself a place in archaeology ever since this branch of science began to use
aerial and satellite imaging. In land surveying, GPS has virtually become an exclusive method for
pinpointing sites in basic networks. Everywhere around the world, continental and national GPS
networks are emerging that, in conjunction with the global ITRF, provide homogenous and highly
accurate networks of points for density and point to point measurements. At a regional level, the
number of tenders to set up GPS networks as a basis for geo-information systems and cadastral
land surveys is growing
Fig 4.5 Application in Science and Research

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CONCLUSION CHAPTER-5
AVL systems generally include a network of vehicles that are equipped with a mobile radio
receiver, a GPS receiver, a GPS modem, and a GPS antenna. This network connects with a base
radio consisting of a PC computer station as well as a GPS receiver and interface. GPS uses
interactive maps rather than static map images on the Web. This means users can perform
conventional GPS functions such as zoom, pan, identify and queries.
AVL systems can be used to increase the accountability of field personnel and boost the efficiency
of a company's dispatching procedure. Dispatchers can get a real-time snapshot of driver adherence
to a route, provide customers with an estimated time of arrival, and communicate directly with
drivers. Public safety agencies, such as police department or fire departments, can use AVL
technology to improve response times by being able to dispatch the closest vehicles for
emergencies.
Performance of GPS and GSM receivers is limited by signal reception. So antenna plays an
important role. Also Embedded Linux provides a lot of flexibility in terms of available libraries
and device drivers. The data is extracted by controller from NMEA packets sent by GPS receiver.
From these packets controller calculates useful data like longitude, latitude, height, speed, time
stamp. These data are saved in a specific format and sent over GSM modem every 10s. The time
is hardcoded but can be easily changed. This time will depend on the application for example a
speed measuring or height profiling applications would require frequent data but normal tracking
applications could work with lesser frequent data.

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List of References
 http://www.nxp.com/documents/user_manual/UM10120.pdf
 http://www.coster.info/costerit/teleges/doc/gsm822w.pdf
 http://downloads.ziddu.com/downloadfile/10920775/automaticvehiclelocator.pdf.html
 http://www.123seminarsonly.com/Seminar-Reports/050/97176908-Automatic-Vehicle-
Locator.pdf
 http://www.calccit.org.itsdecision/serv_and_tech/Automatic_vehicle_location/automatic_
vehicle_location_summary.html
 http://www.seminarsonly.com
 http://www.gpsworld.com/gpsworld/article/articleDetail.jsp?id=102387
 http://123seminars.com