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GPS And Applications Seminar Report ‘04
Chapter 1
The Global Positioning System, usually called GPS (the US
military refers to it as NAVSTAR), is an intermediate circular orbit (!")
satellite na#igation system used for determining one$s %recise location and
%ro#iding a highly accurate time reference almost any&here on 'arth or in
'arth orbit(
The first of )* satellites that form the current GPS constellation
(+loc, ) &as %laced into orbit on -ebruary .*, ./0/( The 12th GPS
satellite since the beginning in ./30 &as launched 4arch )., )22* aboard a
5elta roc,et

The initial conce%t of GPS began to ta,e form soon after the
launch of S%utni, in ./13( 6(((( Some scientists and engineers reali7ed that
radio transmissions from a satellite in a &ell8defined orbit could indicate the
%osition of a recei#er on the ground9 This ,no&ledge resulted in the U(S(
Na#y$s de#elo%ment and use of the 9transit9 system in the ./:2$s( This
system, ho&e#er, %ro#ed to be cumbersome to use and limited in terms of
%ositioning accuracy(
Dept. of ME MESCE Kuttippuram
GPS And Applications Seminar Report ‘04
-igure .
Starting in the mid8./32s the U(S( 5e%artment of 5efense
(5"5) began the construction of today$s GPS and has funded, o%erated, and
maintained control of the system it de#elo%ed( '#entually ;.) billion dollars
&ould ta,e GPS from conce%t to com%letion( -ull "%erational !a%acity
(-"!) of GPS &as reached on <uly .3, .//1 (U(S(!(G(, .//:, &&&)( At one
%oint GPS &as renamed NAVSTAR( This name, ho&e#er, seems to be
regularly ignored by system users and others( Although the %rimary use of
GPS &as thought to be for classified military o%erations, %ro#isions &ere
made for ci#ilian use of the system( National security reasons, ho&e#er,
&ould re=uire that ci#ilian access to accurate %ositioning be intentionally

Dept. of ME MESCE Kuttippuram
GPS And Applications Seminar Report ‘04
Chapter 2
GPS &as designed as a system of radio na#igation that utili7es
9ranging9 88 the measurement of distances to se#eral satellites 88 for
determining location on ground, sea, or in the air( The system basically
&or,s by using radio fre=uencies for the broadcast of satellite %ositions and
time( >ith an antenna and recei#er a user can access these radio signals and
%rocess the information contained &ithin to determine the 9range9, or
distance, to the satellites( Such distances re%resent the radius of an imaginary
s%here surrounding each satellite( >ith four or more ,no&n satellite
%ositions the users$ %rocessor can determine a single intersection of these
s%heres and thus the %ositions of the recei#er ( The system is generally
com%rised of three segments?
.( The s%ace segment
)( The control segment
@( The user segment

The s%ace segment consists of )* satellites, each in its o&n orbit
..,222 nautical miles abo#e the 'arth( The user segment consists of
recei#ers, &hich you can hold in usersA hands or mount in usersA #ehicle(
The control segment consists of ground stations located around the &orld
that ma,e sure the satellites are &or,ing %ro%erly
Dept. of ME MESCE Kuttippuram
GPS And Applications Seminar Report ‘04
2.1.1 Orbit
-igure )
The GPS s%ace segment uses a total of )* satellites in a
constellation of siB orbiting %lanes( This configuration %ro#ides for at least
four e=ually8 s%aced satellites &ithin each of the siB orbital %lanes( The
orbital %ath is continuous in relation to the earth, meaning that a satellite$s
orbit &ill follo& the same %ath on the earth &ith each orbit( At .2,/22nm
()2,)22,m) GPS satellites are able to com%lete one orbit around the earth
e#ery .) hours( GPS satellites orbit at a 118degree inclination to the
e=uatorial %lane( This s%ace segment configuration %ro#ides for a minimum
of 1 satellites to be in #ie& from any %lace on earth, fulfilling the necessary
four needed for three8dimensional %ositioning(
2.1.2 Freqe!"ie#
The GPS satellite, li,e other telecommunication satellites, uses
radio signal transmission for distribution of data used in %ositioning
com%utations( 'ach satellite continuously transmits a com%osite s%read
s%ectrum signal on t&o C band fre=uencies( C. transmits at .131(*) 4D7
Dept. of ME MESCE Kuttippuram
GPS And Applications Seminar Report ‘04
and C) transmits at .))3(:24D7( +oth carrier fre=uencies are %hase8
modulated &ith the Precise code (P8code)( The C. carrier is additionally
%hase8modulated &ith the !oarseEAc=uisition8code( A Na#igation 4essage
is also modulated on the C.8 !EA8code signal( 'ach satellite transmits a
uni=ue code, allo&ing the recei#er to identify the different code of each

2.1.$ C%&e#
-irst obser#ation of these codes &ould suggest that they are
random( n fact, all GPS codes are Pseudo Random Noise (PRN) codes by
design( >ith the a%%ro%riate recei#er one can see that these codes actually
follo& a &ell 8 defined, %redictable se=uence( Recei#ing e=ui%ment is used
to find the highest correlation bet&een a ,no&n GPS code and the radio
transmission of that code recei#ed by the user( "nce a correlation is found
the user is able to find the lag time bet&een the ,no&n time of code
broadcast and the time the code &as recei#ed by the user( The lag is the time
it ta,es the code to get from the GPS satellite to the user$s recei#er( This time
can then be used to determine the distance bet&een the ,no&n satellite
%osition and the user %osition(
The broadcast of !oarse Ac=uisition !ode (!EA8code) &as
designed for ci#ilian a%%lications of the GPS( The !EA8code is a#ailable to
#irtually anybody at any time, %ro#ided they ha#e the right e=ui%ment(
Gi#en the %otential for harmful a%%lications of the GPS, the
designers of the system built into the !EA8codes &hat is ,no&n as selecti#e
a#ailability( Selecti#e a#ailability is an intentional inaccuracy in a satellite$s
onboard cloc, that changes o#er time( This intentional inaccuracy is ,no&n
as cloc, dither and is classified GPS information( The result of cloc, dither
is essentially a degradation of na#igational accuracy(
Dept. of ME MESCE Kuttippuram
GPS And Applications Seminar Report ‘04
The broadcast of Precise8code (P8codes) &as designed for
military a%%lications and is generally restricted to authori7ed %ersonnel and
organi7ations( The P8code is a .2 4D7 PRN code carried on both C. and
C)( -or additional security the Anti8S%oofing (A8S) mode can be engaged(

The Na#igation 4essage is carried on the C. fre=uency as 12D7
signal( This signal carries information concerning the satellite orbit %osition,
cloc, corrections and other system %arameters( GPS authorities may also
degrade and falsify this information in an effort to limit ci#ilian access to
eBtremely accurate na#igational techni=ues(
2.1.' Ti(e a!& p#e&%)ra!*e#
"n board each GPS satellite is a highly accurate atomic cloc,(
9These cloc,s are by nature #ery stable (they might gain or lose a second in
@2,222 years)(9 n order for accurate measurements of time to ha%%en
bet&een the GPS and the user, nearly eBact synchroni7ation is needed
bet&een satellite time and user time( Since the user$s recei#er is generally an
inaccurate time%iece eBact synchroni7ation is not easily a#ailable(
Accurate %ositioning can be achie#ed, ho&e#er, by using
%seudo8 ranges( A %seudo8range is an inaccurate distance established
bet&een a satellite and a recei#er( 5es%ite this inaccuracy, determining a
distance bet&een the recei#er and a ,no&n satellite location %ro#ides a
s%here of reference( The radius of this s%here of reference is e=ual to the
%seudo8range established bet&een the GPS satellite and the recei#ing unit(
>ith four s%heres of reference from four different satellites a user has the
s%atial %ositions needed for three dimensional %ositioning( The intersection
%oint of these four s%heres &ill result in an inaccurate location for the
Dept. of ME MESCE Kuttippuram
GPS And Applications Seminar Report ‘04
recei#er( To gain a more accurate reading the user can adFust for the initial
time inaccuracy by lo&ering or raising the amount of time lag originally
determined( >ith time adFustments, additional com%utations can result in
more accurate distances and thus greater accuracy in %ositioning(
-igure @
The control or ground segment of the GPS consists of unmanned
monitor stations located around the &orld(Da&aii and G&aFalein in the
Pacific "ceanH 5iego Garcia in the ndian "ceanH Ascension sland in the
Atlantic "ceanH and !olorado S%rings, !olorado)( The GPS 4aster !ontrol
Station (4!S) is located on the -alcon Air -orce +ase in !olorado( The
monitoring stations trac, any GPS satellites in #ie& and collect ranging
information from the radio broadcast of each #ie&able satellite( As
information is collected it is sent bac, to master control for %rocessing(
4aster control uses this data to create a na#igation message containing
%recise orbit %ositions, time adFustments, and system %arameters( 4onitoring
stations &ith u%lin, ca%abilities can then transmit the na#igation message
bac, u% to the a%%ro%riate GPS satellite( Subsets of this na#igation message
are rebroadcast for use by recei#ing e=ui%ment(
Dept. of ME MESCE Kuttippuram
GPS And Applications Seminar Report ‘04
-igure *
The user segment consists of the a%%ro%riate antenna, recei#er,
and %rocessor used to gain access to GPS( >ith this e=ui%ment a userAs can
recei#e GPS transmissions and com%ute their %recise %osition, #elocity, and
time( This segment includes a #ariety of %roducts used for different
a%%lications? marine na#igation, ma% sur#eying, trac,ing #ehicles, search
and rescue, and many others(
2.$.1 SPS + Sta!&ar& P%#iti%!i!* Ser,i"e
Standard Positioning Ser#ice (SPS) is a free ser#ice a#ailable to
ci#ilian users of GPS( SPS is broadcast from the GPS constellation as !EA8
code on the C. fre=uency( t is designed around a limited standard of
%osition and timing accuracy that is a#ailable to &orld&ide users &ithout
restrictions( The accuracy (and the intentional degradation through selecti#e
a#ailability) of SPS is established by the U(S( 5e%artment of 5efense based
on national security interest( Accuracy of SPS &as initially designed to be
&ithin .22 hori7ontal meters( !hanges in consumer end recei#er8%rocessing
Dept. of ME MESCE Kuttippuram
GPS And Applications Seminar Report ‘04
technology, ho&e#er, ha#e increased the degree of accuracy that can be
achie#ed &ith SPS(
2.$.2 PPS + Pre"i#e P%#iti%!i!* Ser,i"e
+ecause of itAs greater accuracy the Precise Positioning Ser#ice
(PPS) is a#ailable only to U(S( and allied military, some U(S( Go#ernment
agencies, and authori7ed ci#ilian users( !ry%togra%hic e=ui%ment and ,eys
and s%ecially e=ui%%ed recei#ers are needed for use of the PPS( Dori7ontal
accuracy is %redictable to )) meters(

Dept. of ME MESCE Kuttippuram
GPS And Applications Seminar Report ‘04
Chapter III
A GPS recei#erAs Fob is to locate four or more of these satellites,
figure out the distance to each, and use this information to deduce its o&n
location( This o%eration is based on a sim%le mathematical %rinci%le called
trilateration(Trilateration is based on the fact that a body cannot occu%y t&o
%ositions in s%ace simultaneously( Trilateration can be done in t&o &ays
.( )85 Trilateration
)( @85trilateration

f an obFect is :)1 miles from A it could be any&here on a circle
around A that has a radius of :)1 miles(

-igure 1
Dept. of ME MESCE Kuttippuram
GPS And Applications Seminar Report ‘04
And if the obFect is :/2 miles from + and this information is
combined &ith the former information, &e ha#e t&o circles that intersect to
get the %osition &hich results in t&o %ositions And &ith a third information
&e can clearly s%ot the eBact %osition This same conce%t &or,s in three8
dimensional s%ace, as &ell, but has s%heres instead of circles(
Dept. of ME MESCE Kuttippuram
GPS And Applications Seminar Report ‘04

Fi*re /
Fundamentally, three-dimensional trilateration isn't much different
from two-dimensional trilateration, but it's a little trickier to visualize. Imagine
the radii from the examples in the last section going off in all directions. o
instead of a series of circles, you get a series of spheres.
f a %erson ,no& he is .2 miles from satellite A in the s,y, he could be
any&here on the surface of a huge, imaginary s%here &ith a .28mile radius(
Dept. of ME MESCE Kuttippuram
GPS And Applications Seminar Report ‘04
f he also ,no&s he is .1 miles from satellite + he can o#erla% the first
s%here &ith another, larger s%here( The s%heres intersect in a %erfect circle(
f he ,no&s the distance to a third satellite, he gets the third s%here, &hich
intersects &ith this circle at t&o %oints(
Dept. of ME MESCE Kuttippuram
GPS And Applications Seminar Report ‘04
The 'arth itself can act as a fourth s%here 88 only one of the t&o
%ossible %oints &ill actually be on the surface of the %lanet, so you can
eliminate the one in s%ace( Recei#ers generally loo, to four or more
satellites, ho&e#er, to im%ro#e accuracy and %ro#ide %recise altitude
information( n order to ma,e this sim%le calculation, then, the GPS recei#er
has to ,no& t&o things?
• The location of at least three satellites abo#e him
• The distance bet&een he and each of those satellites
The GPS recei#er figures both of these things out by analy7ing
high8fre=uency, lo&8%o&er radio signals from the GPS satellites( +etter
units ha#e multi%le recei#ers, so they can %ic, u% signals from se#eral
satellites simultaneously(
Radio &a#es are electromagnetic energy, &hich means they
tra#el at the s%eed of light (about .0:,222 miles %er second, @22,222 ,m %er
second in a #acuum)( The recei#er can figure out ho& far the signal has
tra#eled by timing ho& long it too, the signal to arri#e(
Dept. of ME MESCE Kuttippuram
GPS And Applications Seminar Report ‘04
Chapter I0
-igure 3
.( 5istance to a satellite is determined by measuring ho& long a
radio signal ta,es to reach us from that satellite(
)( To ma,e the measurement &e assume that both the satellite and
our recei#er are generating the same %seudo8random codes at
eBactly the same time(
@( +y com%aring ho& late the satellite$s %seudo8random code
a%%ears com%ared to our recei#er$s code, &e determine ho& long
it too, to reach us(
*( 4ulti%ly that tra#el time by the s%eed of light and you$#e got
At a %articular time, the satellite begins transmitting a long,
digital %attern called a %seudo8random code( The recei#er begins running the
same digital %attern also eBactly at midnight( >hen the satellite$s signal
reaches the recei#er, its transmission of the %attern &ill lag a bit behind the
recei#er$s %laying of the %attern(
Dept. of ME MESCE Kuttippuram
GPS And Applications Seminar Report ‘04
The length of the delay is e=ual to the signal$s tra#el time( The
recei#er multi%lies this time by the s%eed of light to determine ho& far the
signal tra#eled( Assuming the signal tra#eled in a straight line, this is the
distance from recei#er to satellite( n order to ma,e this measurement, the
recei#er and satellite both need cloc,s that can be synchroni7ed do&n to the
nanosecond( To ma,e a satellite %ositioning system using only synchroni7ed
cloc,s, you &ould need to ha#e atomic cloc,s not only on all the satellites,
but also in the recei#er itself( +ut atomic cloc,s cost are too eB%ensi#e for
e#eryday consumer use(
The Global Positioning System has a cle#er, effecti#e solution to
this %roblem( '#ery satellite contains an eB%ensi#e atomic cloc,, but the
recei#er itself uses an ordinary =uart7 cloc,, &hich it constantly resets( n a
nutshell, the recei#er loo,s at incoming signals from four or more satellites
and gauges its o&n inaccuracy(
Dept. of ME MESCE Kuttippuram
GPS And Applications Seminar Report ‘04
Chapter 0
deally, GPS recei#ers &ould easily be able to con#ert the !EA
and P(I)8code measurements into accurate %ositions( Do&e#er, a system
&ith such com%leBity lea#es many o%enings for errors to affect the
measurements( The follo&ing are se#eral causes of error in GPS
-igure 0
1.1. CLOC.S
+oth GPS satellites and recei#ers are %rone to timing errors(
Satellites often %ossess cesium atomic cloc,s( Ground stations throughout
the &orld monitor the satellites to ensure that the atomic cloc,s are accurate(
Recei#er cloc, error is un,no&n and often de%ends on the oscillator
%ro#ided &ithin the unit( Do&e#er, it can be calculated and then eliminated
once the recei#er is trac,ing at least four satellites(
Dept. of ME MESCE Kuttippuram
GPS And Applications Seminar Report ‘04
The ionos%here is one of the leading causes of GPS error( The
s%eed of light #aries due to atmos%heric conditions( As a result, errors
greater than .2 meters may arise( To com%ensate for these errors, the second
fre=uency band C) &as %ro#ided( +y com%aring the %hase difference
bet&een the C. and C) signals, the error caused by the ionos%here can be
calculated and eliminated(
The antenna recei#es not only direct GPS signals, but also
multi%ath signals? reflections of the radio signals off the ground andEor
surrounding structures (buildings, canyon &alls, etc)( -or long multi%ath
signals, the recei#er itself can filter the signals out( -or shorter multi%ath
signals that result from reflections from the ground, s%ecial antenna features
may be used such as a ground %lane, or a cho,e ring antenna( Shorter
multi%ath signals from ground reflections can often be #ery close to the
direct signals, and can greatly reduce %recision(
n the %ast, the ci#ilian signal &as degraded, and a more accurate
Precise Positioning Ser#ice &as a#ailable only to the United States military,
its allies and other, mostly go#ernment users( Do&e#er, on 4ay ., )222,
then US President +ill !linton announced that this 9Selecti#e A#ailability9
&ould be turned off, and so no& all users enFoy nearly the same le#el of
access, allo&ing a %recision of %osition determination of less than )2 meters(
Dept. of ME MESCE Kuttippuram
GPS And Applications Seminar Report ‘04
Chapter 0I
'#en if there are many %roblems %ertaining to accuracy due to
errors in measurement,the accuracy of GPS can be im%ro#ed in a number of

/.1. DIFFERENTIAL GPS 4DGPS5 hel%s correct these errors( The
basic idea is to gauge GPS inaccuracy at a stationary recei#er station &ith a
,no&n location( Since the 5GPS hard&are at the station already ,no&s its
o&n %osition, it can easily calculate its recei#er$s inaccuracy( The station
then broadcasts a radio signal to all 5GPS8e=ui%%ed recei#ers in the area,
%ro#iding signal correction information for that area( n general, access to
this correction information ma,es 5GPS recei#ers much more accurate than
ordinary recei#ers(
5ifferential correction techni=ues are used to enhance the
=uality of location data gathered using global %ositioning system (GPS)
recei#ers( 5ifferential correction can be a%%lied in real8time directly in the
field or &hen %ost %rocessing data in the office( Although both methods are
based on the same underlying %rinci%les, each accesses different data
sources and achie#es different le#els of accuracy( !ombining both methods
%ro#ides fleBibility during data collection and im%ro#es data integrity(
The underlying %remise of differential GPS (5GPS) is that any
t&o recei#ers that are relati#ely close together &ill eB%erience similar
atmos%heric errors( 5GPS re=uires that a GPS recei#er be set u% on a
%recisely ,no&n location( This GPS recei#er is the base or reference station(
The base station recei#er calculates its %osition based on satellite signals and
Dept. of ME MESCE Kuttippuram
GPS And Applications Seminar Report ‘04
com%ares this location to the ,no&n location( The difference is a%%lied to
the GPS data recorded by the second GPS recei#er, &hich is ,no&n as the
ro#ing recei#er( The corrected information can be a%%lied to data from the
ro#ing recei#er in real time in the field using radio signals or through %ost
%rocessing after data ca%ture using s%ecial %rocessing soft&are(
ENHANCEMENT 4EDGE5 is an effort to integrate 5GPS into %recision
guided munitions such as the <oint 5irect Attac, 4unition (<5A4)(
>ide Area Augmentation System is the latest method of
%ro#iding better accuracy from the GPS constellation( t is similar in
%rinci%le the 5GPS ca%ability that is built into all Garmin and many other
units eBce%t that a second recei#er is not re=uired( nstead of a beacon
recei#er the correction data is sent #ia a geo8stationary satellite and is
decoded by one of the regular channels already %resent in the GPS recei#er(
Thus one of the .) channels can be designated to decode regular GPS
signals or can be used to decode the >AAS data( Actually, as currently
im%lemented, &hen >AAS is enabled t&o channels &ill be dedicated to
>AAS( >hile >AAS is the name of the im%lementation of this technology
in the US the system is intended for &orld&ide use( The generic name for
>AAS is S+AS (S%ace +ased Augmentation System) or >A5GPS (>ide
Area 5ifferential GPS)(
The &ay this &or,s is that a set of ground stations all o#er the
US collect correction data relati#e to the area of the country they are located
in( The entire data is then %ac,aged together, analy7ed, con#erted to a set of
correction data by a master station and then u%loaded to the geo8stationary
satellite, &hich in turn transmits the data do&n to the local GPS recei#er(
Dept. of ME MESCE Kuttippuram
GPS And Applications Seminar Report ‘04
The GPS recei#er then figures out &hich data is a%%licable to its current
location and then a%%lies the a%%ro%riate corrections to the recei#er( Similar
systems are being set u% in other areas of the &orld but they are not ye n
addition to correction information the ground stations can also identify a
GPS satellite that is not &or,ing &ithin s%ecification thereby im%ro#ing the
integrity of the system for a#iation use(
is similar to >AAS, in that similar correction data are used( +ut in this case,
the correction data are transmitted from a local source, ty%ically at an air%ort
or another location &here accurate %ositioning is needed( These correction
data are ty%ically useful for only about a thirty to fifty ,ilometer radius
around the transmitter(
/.1. -IDE AREA GPS ENHANCEMENT 4-AGE5 is an attem%t to
im%ro#e GPS accuracy by %ro#iding more accurate satellite cloc, and
e%hemeris (orbital) data to s%ecially8e=ui%%ed recei#ers(
a%%roach for a %recise GPS8based %ositioning system( n this a%%roach,
accurate determinination of range signal can be resol#ed to an accuracy of
less than .2 centimeters( This is done by resol#ing number of cycles in
&hich the signal is transmitted and recei#ed by the recei#er( This can be
accom%lished by using a combination of differential GPS (5GPS) correction
data, transmitting GPS signal %hase information and ambiguity resolution
techni=ues #ia statistical tests 8 %ossibly &ith %rocessing in real8time (real8
time ,inematic %ositioning

Dept. of ME MESCE Kuttippuram
GPS And Applications Seminar Report ‘04
Chapter 0II
Army %eo%le &ere the first to use and they themsel#es are the
intensi#e users( Their use is incommensurable
7.1.1. Gi&a!"e
-igure /
The %rimary military %ur%ose is to allo& im%ro#ed command
and control of forces through an enhanced ability to accurately s%ecify target
locations for cruise missiles or troo%s( The satellites also carry nuclear
detonation detectors(
-or eBam%le U(S( 4arines used GPS8guided %arachutes to carry
su%%lies to soldiers in an ra= combat 7one for the first time on August /(
Dept. of ME MESCE Kuttippuram
GPS And Applications Seminar Report ‘04
A large %art of modern munitions, the so8called 9smart bombs9
or %recision8guided munitions, use GPS( GPS Fammers are a#ailable, from
Russia, and are about the si7e of a cigarette boB( The U(S( go#ernment
belie#es that such Fammers &ere used occasionally during the U(S( in#asion
of Afghanistan( Some officials belie#e that Fammers could be used to attract
the %recision8guided munitions to&ards noncombatant infrastructureH other
officials belie#e that the Fammers are com%letely ineffecti#e( n either case,
the Fammers are attracti#e targets for anti8radiation missiles
7.2 AIR
-igure .2
GPS offers an ineB%ensi#e and reliable su%%lement to eBisting
na#igation techni=ues for aircraft( !i#il aircraft ty%ically fly from one
ground beacon, or &ay%oint, to another( >ith GPS, an aircraft$s com%uters
Dept. of ME MESCE Kuttippuram
GPS And Applications Seminar Report ‘04
can be %rogrammed to fly a direct route to a destination( The sa#ings in fuel
and time can be significant(
GPS can sim%lify and im%ro#e the method of guiding %lanes to a
safe landing, es%ecially in %oor &eather( >ith ad#anced GPS systems,
air%lanes can be guided to touchdo&n e#en &hen #isibility is %oor( -or the
%ri#ate %ilot, ineB%ensi#e GPS systems %ro#ide %osition information in a
%ractical, sim%le, and useful form(
7.2.1. GPS Na,i*ati%! i! the Air
Pilots on long distance flights &ithout GPS rely on na#igational
beacons located across the country( Using GPS, aircraft can fly the most
direct routes bet&een air%orts(
7.2.2. GPS i! the C%"9pit
-igure ..
Pilots often rely on GPS to na#igate to their destinations( A GPS
recei#er in the coc,%it %ro#ides the %ilot &ith accurate %osition data and
hel%s him or her ,ee% the air%lane on course(
Dept. of ME MESCE Kuttippuram
GPS And Applications Seminar Report ‘04
7.$. Sea
7.$.1 Nati"a: Chart Err%r
-igure .)
The data collected from satellite na#igation systems %ro#ide
more accurate information for ma%s and nautical and aeronautical charts(
This eBam%le demonstrates ho& charts are u%dated to %re#ent na#igational
misha%s( GPS is a %o&erful tool that can sa#e a shi%$s na#igator hours of
celestial obser#ation and calculation( GPS has im%ro#ed efficient routing of
#essels and enhanced safety at sea by ma,ing it %ossible to re%ort a %recise
%osition to rescuers &hen disaster stri,es(
GPS im%ro#es efficiency on land as &ell( 5eli#ery truc,s can
recei#e GPS signals and instantly transmit their %osition to a central
dis%atcher( Police and fire de%artments can use GPS to dis%atch their
#ehicles efficiently, reducing res%onse time( GPS hel%s motorists find their
&ay by sho&ing their %osition and intended route on dashboard dis%lays(
Railroads are using GPS technology to re%lace older, maintenance8intensi#e
mechanical signals
Dept. of ME MESCE Kuttippuram
GPS And Applications Seminar Report ‘04
7.' LAND
7.'.1. GPS i! 0ehi":e#
4any ty%es of GPS systems can be used on #ehicles, %ro#iding
the dri#er &ith the current %osition and a local ma%(
7.'.2 Mappi!* the Earth
Sur#eyors and ma% ma,ers use GPS for %recision %ositioning(
GPS is often used to ma% the location of such facilities as tele%hone %oles,
se&er lines, and fire hydrants( Sur#eyors use GPS to ma% construction sites
and %ro%erty lines( -orestry, mineral eB%loration, and &ildlife habitat
management all use GPS to %recisely define %ositions of im%ortant assets
and to identify changes(
5uring data collection, GPS %oints can be assigned codes to
identify them as roads, streams, or other obFects( These data can then be
com%ared and analy7ed in com%uter %rograms called Geogra%hic
nformation Systems (GS)(
7.'.$ Sr,e;i!* -ith GPS
Sur#eying that %re#iously re=uired hours or e#en days using
con#entional methods can be done in minutes &ith GPS(
7.'.' Set Y%r -at"h
+ecause GPS includes a #ery accurate time reference, the
system is also &idely used for time,ee%ing( GPS recei#ers can dis%lay time
accurate to &ithin .12 billionths of a second(
Dept. of ME MESCE Kuttippuram
GPS And Applications Seminar Report ‘04
7.'.1 Ma!a*i!* the La!&
The use of GPS is &ides%read in field that re=uire geos%atial
information for managing assets o#er large areas( -orestry, mineral
eB%loration, and &ildlife habitat management all use GPS to %recisely define
%ositions of im%ortant assets and to identify changes(
7.'./ GPS a!& A*ri":tre
GPS recei#ers installed in farm e=ui%ment %ro#ide accurate
%osition information( This enables farmers to a%%ly fertili7ers and har#est
cro%s &ith great %recision(
7.'.7 Yie:& Map
-igure .@
4a%s of cro% yield can be made using agricultural GPS systems(
The ma% sho&n here indicates ho& cro% yield #aries across a field( These
ma%s can be created during har#esting, allo&ing farmers to accurately %lan
ho& the fields should be used and fertili7ed for future cro%s(
Dept. of ME MESCE Kuttippuram
GPS And Applications Seminar Report ‘04
7.'.< Ne= Fr%!tier# i! S"ie!"e
-igure .*
GPS has made scientific field studies throughout the &orld more
accurate and has allo&ed scientists to %erform ne& ty%es of geogra%hic
analyses( Geologists use GPS to measure eB%ansion of #olcanoes and
mo#ement along fault lines( 'cologists can use GPS to ma% differences in a
forest cano%y( +iologists can trac, animals using radio collars that transmit
GPS data( Geogra%hers use GPS to define s%atial relationshi%s bet&een
features of the 'arth$s surface(
7.1.1 Ar"hite"tre
GPS is used in architectural sitings( >hen used &ith @5
modeling, GPS %ro#ides a more realistic conteBt for architectural design(
Dept. of ME MESCE Kuttippuram
GPS And Applications Seminar Report ‘04
7.1.2 E)C%((er"e
!onducting research to de#elo% secure transactions using GPS(
The system &ould feature real8time information on users as &ell as
a%%lications to reduce user fears of com%uter 9hac,ing(9
7.1.$ E&"ati%!
GPS is used to trac, transmission and %o&er line distribution
net&or, ins%ections, trac, container mo#ements, and ma% the location of
ground &ater sources and %ollution
7.1.' Ge%*raphi" I!>%r(ati%! S;#te(#
Remote Sensing Satellites the satellite RS8.5 &ill be launched
from Srihari,ota on Se%tember )/, .//3( "ne of the eB%erimental units on
RS8.5 is a *(.18,g Satellite Position System( Using the Global Positioning
System recei#er on the satellite, the SPS &ill determine the %osition of the
satellite in orbit(
7.1.1 De,e:%p(e!t %> GPS re"ei,er#
ndia has begun to manufacture Global Positioning System
recei#ers, in a %roFect funded by the 5e%artment of 'lectronics and the
5efence Research 5e#elo%ment "rgani7ation( These recei#ers are u% to the
highest standards at half the im%orted cost( The ndian8made recei#ers are
being used commercially by boat o&ners and some military #ehicles and
Dept. of ME MESCE Kuttippuram
GPS And Applications Seminar Report ‘04
7.1./ Gr%!& Tra!#p%rtati%!
+uses Run on Time Than,s to GPS in +angalore, ndia A select
number of buses in the south ndian city of +angalore are running on time
than,s to the constellation of Global Positioning System (GPS) na#igation((
Recei#ers built by +angalore$s based +harat 'lectrical Ctd(, &ere mounted
on )22 of the city$s ),@22 buses in a %ilot %roFect about a year ago( The
%rogram is hel%ing ensure that the buses remain on schedule and ma,e all
their designated sto%s( The recei#ers continuously record each bus$
coordinates, &hich are con#erted by soft&are into locations identifiable by
,no&n landmar,s e#ery )22 meters along the bus route( The recei#ers are
able to store @ days of recordings to %roduce a record of the scheduled
%erformance( This system has hel%ed identify missed tri%s and catch
s%eeding dri#ers
3.1.7 I!>ra#tr"tre De,e:%p(e!t
Digh&ay Automation System ? The Digh&ay Automation
System is a %roFect that %lans to lin, the ndian road and communication
infrastructure( The idea for DAS came from the global %ositioning system(
'lectronic ,ios,s &ill be set e#ery 12 ,m on the high&ays and the #ehicles
&ill ha#e an electronic monitoring de#ice( Truc, o%erators &ill be the first
users of DAS(
7.1.< Mi!i!* ? C%!#tr"ti%!
!oal 4ining? The 4inister of State for !oal, 5ili% Ray, &ould
li,e to increase the use of GPS technology to locate ne& mineral resources,
im%ro#e scientific %lanning for the eB%loitation of natural resources, and
Dept. of ME MESCE Kuttippuram
GPS And Applications Seminar Report ‘04
better management systems( De said that GPS is already being used in many
areas of coal mining(
+eginning in A%ril .//*, one of the largest, dee%est %i%eline
routes &as ma%%ed( This &as %ossible using differential global %ositioning
system to calculate the %osition of the to& fish from the shi%, &hich &as
usually )228m ahead( The %i%eline that &as laid &as )*8in( for 322 miles at
de%ths in the Arabian Sea to @,122 m( GPS has been eBtensi#ely used in
5elhi 8 Utility 4a%%ing ProFect( -or %hotogrammatry &or, GPS !ontrol
Grid Net&or, co#ering an area of .:22 s=(,m has been established &ith
about 122 g%s control %oint at e#ery @81 ,m on ground( The GPS control
grid net&or, %roFect &ill be com%leted by 4ay )222 co#ering entire 5elhi
Vehicle Cocation
>e &ant to de%loy the GPS net&or, in almost the &hole
country so that &e can %ro#ide trac,ing systems not only for #ehicle %osition
but other %arameters of the #ehicle such as remaining fuel, s%eed, ha7ard
&arnings, and %redefined messages( All these things ha#e to be monitored

Ci,i" b%&; i!#ta::# GPS i! "%!#er,a!"; tr"9#A T&el#e
5um%er %lacers and .: cor%oration conser#ancy lorries might soon ha#e
Global Positioning System (GPS) instruments in %lace(
A re#ie& of the %erformance of the Global Positioning System
(GPS), on four dum%er %lacer truc,s of the !oimbatore !or%oration, has
been found to be effecti#e in trac,ing #ehicles( !onse=uently, the ci#ic body
Dept. of ME MESCE Kuttippuram
GPS And Applications Seminar Report ‘04
has decided to install it in more #ehicles engaged in conser#ancy o%erations(
Dept. of ME MESCE Kuttippuram
GPS And Applications Seminar Report ‘04
As a test case, the !or%oration had installed the GPS in four of
its .: dum%er %lacers in an effort at finding out &hether the technology
could hel% ensure trans%arency in &aste dis%osal( The $%assi#e #ehicle
trac,ing system$ had recorded the entire tri% of each dum%er %lacer( A
%ri#ate institution that had de#elo%ed the GPS %ro#ided the monitoring
office at the !or%oration a $Tri%4a%%$ soft&are and a geo reference city
ma%, containing the names of all the roadsEstreets and the &aste dum%
locations across the city( A tri% summary &as do&nloaded from the GPS in
one of the truc,s on Tuesday to re#ie& its %erformance and also to chec,
&hether there &ere any route di#ersions( t &as found that the GPS fulfilled
the re=uirements of the !or%oration and hence it had been decided to installs
.) more dum%ers and lorries &ith the GPS
Dept. of ME MESCE Kuttippuram
GPS And Applications Seminar Report ‘04
Chapter 0III

The digital re#olution combined &ith the %rogressing
communication theory brought tremendous ad#ancements in information
re#olution( '#en if there are %roblems &ith the %resent GPS system it offers
a credible ser#ice to both high end and lo& end users( There are also a
#ariety of techni=ues a#ailable to correct the %itfalls( As of no& the %resent
research in the field is to reduce the cost, increase the accuracy( t also aims
at reducing the &eight and to clear the line of sight bet&een GPS recei#er
and four satellites(
Dept. of ME MESCE Kuttippuram
GPS And Applications Seminar Report ‘04
o Global Positioning System Standard Positioning Ser#ice S%ecification,
)nd 'dition, <une ), .//1(
o Doffmann8>ellenhof, +( D( Cichtenegger, and <( !ollins( .//*( GPS?
Theory and Practice( @rd ed( Ne& Ior,? S%ringer8Verlag(
o Ga%lan, 'lliott 5( ed( .//:( Understanding GPS? Princi%les and
A%%lications( +oston? Artech Douse Publishers(
Other Re:ate& -ebPa*e#A
o &&&(aero(orgEhome(html
o &&&(a#&eb(com
o auto(ho&stuff&or,s(comE
o &&&(trimble(com
o &aas(stanford(eduE
o &&&(garmin(comE
Dept. of ME MESCE Kuttippuram
GPS And Applications Seminar Report ‘04
o&e a great deal to the senior faculty of the 5e%artment of
4echanical 'ngineering, 4'S !ollege of 'ngineering, Gutti%uram for the
successful com%letion of this seminar and its re%ort(
am indebted to Mr. 2i:a: .., Cecturer, 5e%artment of 4echanical
'ngineering &ho guided me throughout this seminar( Dis o#erall guidance
and direction has been res%onsible for the successful com%letion of this
also eB%ress my than,s to our res%ected Dead of the 5e%artment,
Pr%>.T.N. Sath;a!e#ha! for all the assistance he rendered(
also than, my friends for their constructi#e criticism and their
doubts and =uestions hel%ed me a lot(
Cast but not the least eB%ress my sincere than,s to them &hom
inad#ertently failed to mention(
Dept. of ME MESCE Kuttippuram
GPS And Applications Seminar Report ‘04
n the beginning of the ./
century &e had the industrial
re#olution, in the middle of the )2
century &e ha#e the digital re#olution,
and in the da&n of the ).
century &e ha#e the communication re#olution(
The maFor inno#ation &hich u%turned the communication re#olution is the
artificial satellite( Generally satellites use the latest technology for
communication, remote sensing, &eather forecasting and the li,e(
Global %ositioning system, usually called GPS are used to
communicate &ith satellites and &ith recei#ers in the different %arts of the
&orld( This seminar aims to thro& light into the technical details,
ad#antages, %itfalls and maFor a%%lication areas of the GPS systems(
Dept. of ME MESCE Kuttippuram
GPS And Applications Seminar Report ‘04
!ertificate ii
Ac,no&ledgement iii
Abstract i#
!ontents i#
Cist of Tables J -igures #i
)(. SPA!' S'G4'NT
2.1.1 ORBIT
2.1.3 CODES
)()( !"NTR"C S'G4'NT
)(@ US'R S'G4'NT
)(@(. S.P.S
2.3.2 P.P.S
@(. )58TRCAT'RAT"N
@() @58TRCAT'RAT"N
Dept. of ME MESCE Kuttippuram
GPS And Applications Seminar Report ‘04
1(. !C"!GS
1() "N"SPD'R'
:(. 5(G(P(S
:() '(5(G('
:(* C(A(A(S
3(. 4CTARI
3() AR
3(@ S'A
3(* CAN5
Dept. of ME MESCE Kuttippuram
GPS And Applications Seminar Report ‘04
Dept. of ME MESCE Kuttippuram
GPS And Applications Seminar Report ‘04
Dept. of ME MESCE Kuttippuram

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