1. INTRODUCTION
Traditional methods of surveying and navigation resort to tedious field and
astronomical observation for deriving positional and directional information.
Diverse field conditions, seasonal variation and many unavoidable
circumstances always bias the traditional field approach. However, due to rapid
advancement in electronic systems, every aspect of human life is affected to a
great deal. Field of surveying and navigation is tremendously benefited through
electronic devices. Many of the critical situations in surveying/navigation are
now easily and precisely solved in short time.
The NAVSTAR Global Positioning System (GPS) is a satellite-based radio-
positioning and time transfer system designed, financed, deployed, and operated
by the U.S. Department of Defence. GPS has also demonstrated a significant
benefit to the civilian community who are applying GPS to a rapidly expanding
number of applications. What attracts us to GPS is:
 The relatively high positioning accuracies, from tens of metres down to
the millimetre level.
 The capability of determining velocity and time, to an accuracy
commensurate with position.
 The signals are available to users anywhere on the globe: in the air, on the
ground, or at sea.
 It is a positioning system with no user charges that simply requires the
use of relatively low cost hardware.
 It is an all-weather system, available 24 hours a day.
 The position information is in three dimensions, that is, vertical as well as
horizontal information is provided.
The number of civilian users is already significantly greater than that of the
military users. However, for the time being the U.S. military still operates
several "levers" with which they control the performance of GPS . Nevertheless,
despite the handicap of GPS being a military system there continues to be
tremendous product innovation within the civilian sector, and it is ironic that
this innovative drive is partly directed to developing technology and procedures
to overcome some of the constraints to GPS performance which have been
applied by the system's military operators.

2. HISTORY OF GPS
Since the beginning of time, mankind has been trying to figure out a dependable
way to know where they were, and to guide them to where they wanted to go
and get back again. Seamen followed the coastline to keep them from getting
lost. They discovered, when they sailed out into the open sea, that they could
use the position of the stars to chart their courses.
Major developments in early navigation were the compass and the sextant. The
needle of the compass always points north. So even if they didn't knew where
they were, at least they knew in what direction they were travelling. The sextant
measures the exact angles of stars, the moon and the sun above the horizon by
the use of adjustable mirrors. Early sextants could only measure the latitude and
sailors were still not able to work out their longitude.
As this was determined to be a serious enough problem, in the seventeenth
century, Great Britain formed a group of well-known scientists called the Board
of Longitude. They offered a substantial cash reward to any person who could
find a way of working out the longitude of a ship within thirty nautical miles. In
1761, a man named John Harrison developed a timepiece called a chronometer.
This invention lost or gained only about one second a day. Sextants and
chronometers were used together to provide travellers with their latitude and
longitude.
Radio-based navigation systems were developed in the early twentieth century,
and were used in World War II. As this technology advanced, both ships and
airplanes used ground-based radio-navigation systems. The disadvantage of
using a system that uses ground generated radio waves is that a choice has to
made between a high-frequency system that is accurate, but does not cover a
wide area, and a low-frequency system that covers a wide area, but is not very
accurate.
When Sputnik was launched into space by Russia on October 4th, 1957 it
became known that "artificial stars" could be used for navigation. The evening
after the launch researchers of the Massachusetts Institute of Technology
determined the orbit of the Russian satellite by noting that the Sputnik's radio
signals increased as it approached and decreased as it left. So the fact that a
satellite's position could be tracked from the ground was the first step in
recognizing that a subject's whereabouts on the ground could be determined
using radio signals from the satellite.

3. The U.S. Navy experimented with satellite navigation. In the mid-sixties there
was the Transit System that was developed for submarines carrying Polaris
nuclear missiles. This system has six satellites that circled the earth in polar
orbits. In measuring the Doppler shift of the radio signals the submarines could
locate its position within fifteen minutes.
The Global Positioning System, now commonly known GPS was designed and
built and is operated and maintained by the U.S. Department of Defence. It used
to be known as the Navstar Global Positioning System and was first
brainstormed at the Pentagon in 1973 as they were looking for a satellite system
that was error-proof. In 1978 the first operational GPS satellite was launched.
By the mid-1990s the system was fully operational with 24 satellites.
This incredible new technology was made possible by a combination of
scientific and engineering advances, particularly development of the world's
most accurate timepieces: atomic clocks that are precise to within a billionth of
a second. The clocks were created by physicists seeking answers to questions
about the nature of the universe, with no conception that their technology would
some day lead to a global system of navigation. Today, GPS is saving lives,
helping society in countless other ways, and generating 100,000 jobs in a multi-
billion-dollar industry.
GPS SATELLITE SYSTEM
The 24 satellites that make up the GPS space segment are orbiting the earth
about 12,000 miles above us. They are constantly moving, making two
complete orbits in less than 24 hours. These satellites are travelling at speeds of
roughly 7,000 miles an hour.
GPS satellites are powered by solar energy. They have backup batteries onboard
to keep them running in the event of a solar eclipse, when there's no solar
power. Small rocket boosters on each satellite keep them flying in the correct
path.
Here are some other interesting facts about the GPS satellites (also called
NAVSTAR, the official U.S. Department of Defence name for GPS):
o The first GPS satellite was launched in 1978.
o A full constellation of 24 satellites was achieved in 1994.
o Each satellite is built to last about 10 years. Replacements are constantly
being built and launched into orbit.

4. o A GPS satellite weighs approximately 2,000 pounds and is about 17 feet
across with the solar panels extended.
o Transmitter power is only 50 watts or less.
A GPS SATELLITE SYSTEM
 The United States Department of Defense developed the system,
officially named NAVSTAR GPS (Navigation Signal Timing and
Ranging Global Positioning System), and launched the first experimental
satellite in 1978.
FIRST SATELLITE LAUNCHED BY NAVSTAR

5. WORKING OF GPS
GPS satellites circle the earth twice a day in a very precise orbit and transmit
signal information to earth. GPS receivers take this information and use
triangulation to calculate the user's exact location. Essentially, the GPS receiver
compares the time a signal was transmitted by a satellite with the time it was
received. The time difference tells the GPS receiver how far away the satellite
is. Now, with distance measurements from a few more satellites, the receiver
can determine the user's position and display it on the unit's electronic map.
A GPS receiver must be locked on to the signal of at least three satellites to
calculate a 2D position (latitude and longitude) and track movement. With four
or more satellites in view, the receiver can determine the user's 3D position
(latitude, longitude and altitude). Once the user's position has been determined,
the GPS unit can calculate other information, such as speed, bearing, track, trip
distance, distance to destination, sunrise and sunset time and more.
 The following points provide a summary of the technology at work:
 The control segment constantly monitors the GPS constellation and
uploads information to satellites to provide maximum user accuracy.
 The GPS receiver collects information from the GPS satellites that are in
view.
 The GPS receiver accounts for errors.
 The GPS receiver determines your current location, velocity, and time.
 The GPS receiver can calculate other information, such as bearing, track,
trip distance, distance to destination, sunrise and sunset time, and so on.
 The GPS receiver displays the applicable information on the screen.

6. SEGMENTS OF GPS
The GPS system consists of three segments:-
Space Segment
The Space Segment consists of the constellation of spacecraft and the signals
broadcast by them which allow users to determine position, velocity and time.
 Receive and store data transmitted by the Control Segment stations.
 Maintain accurate time by means of several onboard atomic clocks.
 Transmit information and signals to users on two L-band frequencies.
 Provide a stable platform and orbit for the L-band transmitters.
 The particular satellite that is sending the information.
 Where that satellite should be at any given time (the precise location of
the satellite is called ephemeris data).
 Whether or not the satellite is working properly.
 The date and time that the satellite sent the signal.
 Comprises of a nominal network of 24 GPS satellites in orbit around the
globe.
 Nominal orbit height of 20,200 Km.
 Initial 24Hr operational capability was declared on 8 December, 1993.
 Full 24 Hr operational capability was declared after testing on 17 July,
1995.
 Selective Availability signal degradation was removed in May, 2000.
Control Segment
The Control Segment is the ground facilities carrying out the task of satellite
tracking, orbit computations, telemetry and supervision necessary for the daily
control of the space segment. The control segment is responsible for constantly
monitoring satellite health, signal integrity and orbital configuration from the
ground. The control segment includes the following sections:-
 Master control station
 Monitor stations
 Ground antennas

7. The Control Segment consists of facilities necessary for satellite health
monitoring, telemetry, tracking, command and control, satellite orbit and clock
data computations, and data linking. There are five ground facility stations:
Hawaii, Colorado Springs, Ascension Island, Diego Garcia and Kwajalein. All
are owned and operated by the U.S. Department of Defence and perform the
following functions:
 All five stations are Monitor Stations, equipped with GPS receivers to
track the satellites. The resultant tracking data is sent to the Master
Control Station.
 Colorado Springs is the Master Control Station (MCS), where the
tracking data are processed in order to compute the satellite ephemerides
and satellite clock corrections. It is also the station that initiates all
operations of the space segment, such as spacecraft manoeuvring, signal
encryption, satellite clock-keeping, etc.
 Three of the stations (Ascension Is., Diego Garcia, and Kwajalein) are
Upload Stations allowing for the uplink of data to the satellites. The data
includes the orbit and clock correction information transmitted within the
navigation message, as well as command telemetry from the MCS.
User Segment
The User Segment is the entire spectrum of applications equipment and
computational techniques that are available to the users. The GPS user segment
consists of GPS receiver. The receiver collects and processes signals from the
GPS satellites that are in view and then uses that information to determine and
display your location, speed, time, and so on. Your GPS receiver does not
transmit any information back to the satellites. Overall operation of the Control
and Space Segments is the responsibility of the U.S. Air Force Space
Command, Second Space Wing, Satellite Control Squadron at the Falcon Air
Force Base, Colorado. This is the part of the GPS system with which we are
most concerned -- the space and control segments being largely transparent to
the operations of the navigation function.
• Applications,
• Equipment
• Positioning strategies.

9. GPS –Nowadays
Today's GPS receivers are extremely accurate, thanks to their parallel multi-
channel design. Garmin's 12 parallel channel receivers are quick to lock onto
satellites when first turned on and they maintain strong locks, even in dense
foliage or urban settings with tall buildings. Certain atmospheric factors and
other sources of error can affect the accuracy of GPS receivers. Today's GPS
receivers are extremely accurate, thanks to their parallel multi-channel design.
Garmin's 12 parallel channel receivers are quick to lock onto satellites when
first turned on and they maintain strong locks, even in dense foliage or urban
settings with tall buildings. Certain atmospheric factors and other sources of
error can affect the accuracy of GPS receivers.
 GPS has become a vital global utility, indispensable for modern
navigation on land, sea, and air around the world, as well as an important
tool for map-making and land surveying.
 GPS also provides an extremely precise time reference, required for
telecommunications and some scientific research, including the study of
earthquakes.
 GPS receivers can also gauge altitude and speed with a very high degree
of accuracy.

10. APPLICATIONS OF GPS
MILITARY
GPS allows accurate targeting of various military weapons including
cruise missiles and precision-guided munitions, as well as improved
command and control of forces through improved location awareness.
The satellites also carry nuclear detonation detectors, which form a
major portion of the United States Nuclear Detonation Detection
System. Civilian GPS receivers are required to have limits on the
velocities and altitudes at which they will report coordinates.
AVIATION
Aircraft pilots use GPS technology for en route navigation and airport
approaches. Satellite navigation provides accurate aircraft location
anywhere on or near the earth. A number of attempts were made to
produce a true powered aircraft. However the majority of these efforts
were doomed to failure, being designed by ill-informed amateurs who
did not have a full understanding of the problems being discussed by
Lilienthal and Chanute.

11. NAVIGATORS
Navigation applications are the most famous GPS applications. The
latest releases of those applications allow users to have much
advanced features and facilities.
DeLorme Street Atlas 2010: This is software that enables users to do
things like trip planning, GPS navigation and mapping. This was
much harder to learn how to work with it with the software. It is said
that the latest edition has removed that complexity and made it easy
for the users to use.
Gramin nRoute: This is free software that enables laptop users to
make their work easy with the GPS maps. However, users must
already have a MapSource product running on your computer for
nRoute to work.In addition to those Microsoft AutoRoute and Streets
and Tips are some of the other famous applications.
TRACKING
A tracking applications are not that much popular as the navigation
applications. But, so many people take uses of them. It enables users
to find a location of any object that is tagged with a system.
Top Grossing Apps on iTunes: iPhone users can have this facility
through the iTune store. This made the iPhone look much smart in its
words.
LOC i MOBILE Apps for tracking people: This enables iPhone users
to track people in a particular place at a particular time.

12. GPS Tracking Lite v2.0 is taking the nation by storm: GPS Tracking
v2.0 by Locimobile is their biggest update to date application and it
includes much advanced features than the others.
AGRICULTURE
GPS Machine Guidance is used for tractors and other large
agricultural machines via auto steer or a visual aid displayed on a
screen, which is extremely useful for controlled traffic and row crop
operations and when spraying. As well as guidance, GPS used in
harvesters with yield monitors can provide a yield map of the paddock
being harvested.
FUTURE OF GPS APPLICATIONS
There can be several further implementations also as this GPS has
become widely available. This can be used to provide a solution for
the deforestation. The green plant density of a certain area can be
calculated or estimated. With a comparison and analyze, the
deforestation rate can be calculate and can ask the officials to pay
their attention on those areas.
Cultivation also can be helped with this Global Positioning System.
The empty lands can be explored and let the people to cultivate on
those areas is something that can help the people to improve their
production and the right place for the right product will be available
through this system.
The functioning of the currently available GPS is at a very low level.
This can be developed with advanced features that could be able to
find the areas where marijuana cultivated likewise. The cameras
should be much more sensitive to identify such objects. The research
things will be easy if that kind of facility can be established. The
application developers will have much advanced API for their
development that can give a greater outcome.

13. ADVANTAGES OF GPS
There are many advantages of having a GPS system:
Ease of Navigation
A GPS device is extremely handy. When you are hiking, you can deviate from a
path without worrying about how you will find your way back. When you are
driving, GPS-based navigation systems can provide you with turn-by-turn
directions, a helpful feature in a strange town.
Search Nearby Area
Some GPS systems allow you to search the local area for nearby amenities, such
as hotels, restaurants and gas stations. This is extremely helpful in some
situations. For example, if you are driving cross-country and realize there is a
problem with your car, you can search for nearby auto mechanics and select one
that is along your route. Your GPS system will show you exactly how to get
there.
Water Navigation
GPS devices are perfect for water navigation. Since there are no landmarks in
large bodies of water, boaters in the past had to use a compass and a map to
determine if they were on the right heading, with somewhat imprecise results.
But the advent of GPS systems allowed boaters to figure out their exact position
on the map. In situations where underwater hazards are a problem, GPS devices
allow boaters to steer around hidden dangers.
Other Advantages are:-
1. A GPS system comes with a "panic" button. When this button is pressed an
operator at the GPS carrier can listen in on the conversation and either help you
out or alert the authorities. This will keep you safe in case of accidents or hi
jacks.
2. Your car will never loose your car at a football match or mall. The GPS
service will track the car for you and send its lights flashing.
3. If your vehicle is ever stolen the GPS system will track the vehicle and the
authorities will be able to get it back in no time.

14. 4. A GPS system in a car, boat, plane or haversack will ensure that you are
never lost.
5. A GPS system streamlines supply chains and truck movements. The system
can track goods at any point of time and accurately predict when goods will
reach their destination.
6. GPS systems are used to detect structural problems in buildings and roads
and to predict disasters like earthquakes and so on. The scientific applications of
a GPS system are many.
7. A GPS system can be used to locate a missing person, pet or family. The
device is quite small and is like a watch or button on a collar.
8. A GPS is a great exercise monitor and will help you keep track of your speed
and so on.
9. If you are using a GPS device then you can be found easily if you are
in danger or in accident.
10. GPS device is small enough to get plugged into your car’s cigarette lighter.

15. DISADVANTAGES
ESSENTIAL MAP READING SKILLS
Creating GPS technology that is readily available; our younger generation is
losing the essential ability to read maps. With any computer devise, all can have
problems that may cause the devise to malfunction or break. If you are someone
who relies heavily on a devise that tells you which route to take and it happens
to malfunction, you may not a map available as an alternative. Modern GPS
technology is again dulling general knowledge that everyone should know and
be capable of understanding.
RELYING ON TECHNOLOGY
As mentioned above, some people may rely on their devise too often. Turning
their navigation system on each time they get into the car, even to go to a local
store. Use your sense, your sensibility and your knowledge contained in the best
computer of your brain instead of the GPS in your car.
LOSING INDEPENDENCE AND TRUST ISSUES
This would be important for subcontractors and truck drivers whose company
has installed GPS devises in the vehicles. Now you have Big Brother watching
at all times, no longer can you use the company vehicle for personal chores and
reasons. In the modern era of high fuel costs and the expense of maintaining
vehicle and truck fleets, using a company vehicle for personal reasons is no
longer considered okay.
WAYS TO STOP SATELLITE SIGNALS
Modern technology always has its downfalls. One of these is the intelligence
used to stop satellite signals. A company that uses a fleet of vehicles with GPS
technology installed may find their employees going to certain extents to avoid
detection on their maps. I have heard tales of a simple aluminium can being
placed over the antennae, that will disable the GPS system from being able to
track positions and routes. Please look into this when considering GPS
technology for your fleet vehicles.

16. COMPUTER TECHNOLOGY AND YOU
Although many of us have great electronic devices in our homes and cars, do
we really use them to the best of their ability? Do you even like the technology
you have at your disposal? Consider your GPS devise and its capabilities, are
you going to make use of downloading music and some DVD capabilities? Do
you know how to spell street names accurately to enter into you GPS system?
Making a slight error in spelling may have you going around in circles. Then
you will blame the devise, not yourself. This therefore becomes an extremely
useless devise that may have cost you a lot of money, and some anger and
frustration.
ELECTRONIC WAVES AND YOUR HEALTH
We've all heard how microwaves can be dangerous to your health. We hear
stories or mobile phones and their continuing use causing cancer for those who
use them often. A GPS devise is another form of technology that utilizes
invisible satellite and electro-waves that could also prove to be bad for our
health.
Consider the mobile phone, the GPS satellite in your car, the portable DVD
player playing for the kids. How many electro-magnetic waves are bouncing
around your car?
SATELLITE DETECTION
GPS makes use of satellite technology, bouncing waves from your devise to the
satellite detecting signals to operate. When one of these satellites is
malfunctioning, your GPS may have issues picking up signals. You need to
consider connection times, response times and how often the system is
maintained and repaired. Just like mobile phone coverage, GPS relies on
performance of the coverage to function.
EXPENSE
You will also need to consider the expense of purchasing a GPS system. Fleet
companies could claim them on their business tax, but individuals may not.
These are expensive devices, ranging from a couple of hundred to many
hundred dollars. Is really vital you have this new devise?
So although it has many advantages, it too has disadvantages to you as an
individual and society in general. Those disadvantages above are just some of
the darker sides to popular GPS technology.

17. CONCLUSION
The technology of the Global Positioning System is allowing for
huge changes in society. The applications using GPS are
constantly growing. The cost of the receivers is dropping while
at the same time the accuracy of the system is improving. This
affects everyone with things such as faster Internet speed and
safer plane landings.
Initially developed for military use, GPS is now part of
everyday life; used in mobile phones, in-car navigation and
search and rescue equipment to mention just a few. But there is
a wide variety of equipment and techniques that can be used for
surveying.
GPS was rapidly adapted for surveying, as it can give a position
(Latitude, Longitude and Height) directly, without the need to
measure angles and distances between intermediate points.
Survey control could now be established almost anywhere and it
was only necessary to have a clear view of the sky so the signal
from the GPS satellites could be received clearly.
GPS is similar in some ways to the Trilateration and EDM
except that the known positions are now the GPS satellites (and
their orbits) 20,000 km in space. The equipment and
calculations are extremely complex, but for the user the process
is generally very simple.
The GPS receivers used for surveying are generally more
complex and expensive than those used in everyday life. They
use the two frequencies broadcast by the GPS satellites and they
use the physical characteristic of the GPS signal (the phase) and
sophisticated calculation methods to greatly improve the
accuracy of the positions obtained. These receivers usually have
a separate high-quality antenna.

18. TABLE OF CONTENTS
INTRODUCTION
HISTORY OF GPS
GPS – A SATELLITE SYSTEM
WORKING OF GPS
SEGMENTS OF GPS
GPS NOWADAYS
APPLICAIONS OF GPS
ADVANTAGES OF GPS
DISADVANTAGES OF GPS
CONCLUSION

19. CERTIFICATE
This is to certify that this seminar has been conducted by Kajal Singh on the
topic “GPS TECHNOLOGY” under the graceful guidance of Mr.Dilip Sharma,
as a mandatory part for the completion of their course Bachelor of Technology
in the branch Information and Technology (session 2011-2012).
SIGNATURE:-

20. SEMINAR REPORT
ON
“GLOBAL POSITIONING SYSTEM”
SUBMITTED FOR THE PARTIAL FULFILLMENT OF AWARD OF
BACHELOR OF TECHNOLOGY
IN
COMPUTER SCIENCE AND ENGINEERING
(GLA INSTITUTE OF TECHNOLOGT AND MANAGEMENT)
By
Kajal Singh
CS 3rd year
Under the Guidance of
Mr Dilip Sharma