Proceedings of the International Conference , “Computational Systems and Communication Technology”
8th , MAY 2010 - by Cape Institute of Technology,
Tirunelveli Dt-Tamil Nadu,PIN-627 114,INDIA
USE OF GPS SATELLITE SYSTEM WITH GRID COMPUTING
Sheikyousuf.T1, Rasina begum.B2, Balasubramanian.N3, Mithunkannan.K4, Srinivasan.M5
Student1,4&5, Senior Lecturer2, Assistant Professor3
Department of Computer Science & Engineering1&2,
Department of Computer Applications3,
Mohamed Sathak Engineering College., kilakarai, Tamilnadu 1,2&3,
Sree Sowdambika college of Engineering, Aruppukottai, Tamilnadu4&5.
s.ganeshvel@gmail.com
military .GPS provides specially coded
ABSTRACT:
satellite signals that can be processed in
Our project aims at extending the
a GPS receiver, enabling the receiver to
application domain of the GPs satellite
compute position, velocity and time.
from a mere tracking and positioning
Four GPS satellite signals are used to
satellite system to a earth quake
compute positions in three dimensions
predicting system.
The GPS systems
and the time offset in the receiver clock.
signal can map the ionosphere’s f2
The GPS receivers can be used by
layer. This layer is amplifier of the
anyone and are free to access.
earth’s environmental conditions. When
nominal GPs Operational constellation
the GPS signal is delayed due to
consists of 24 satellites that orbit the
refraction of the ionosphere particle, we
earth in 12 hours. There are often more
are able to map the TEC and thus we
than 24 operational satellites as new
can effectively predict earth quake as
ones are launched to replace older
shown in our study. The earth quake
satellites. The satellite orbits repeat
detection system is proposed to be
almost the same ground track (as the
implemented
earth turns beneath them)
using
a
real
time
distributed environment.
The
once each
day. The orbit altitude is such that the
satellites repeat the same track and
GPS is a Satellite Navigation System.
configuration
GPS is funded by and controlled by the
approximately each 24 hours (4 minutes
U.S Department of Defense (DOD).
earlier each day). There are six orbital
While there are many thousands of civil
planes (with nominally four SVs in
users of GPS world wide, the system was
each), equally spaced (60 degrees
designed for and is operated by the U.S
apart), and inclined at about fifty-five
over
any
point
Proceedings of the International Conference , “Computational Systems and Communication Technology”
8th , MAY 2010 - by Cape Institute of Technology,
Tirunelveli Dt-Tamil Nadu,PIN-627 114,INDIA
degrees with respect to the equatorial
The space component,
plane. This constellation provides the
control component and
user with between five and eight SVs
component.
visible from any point on the earth.
consists of 24 satellites that emit high
2. The
3. User
The space component
frequency radio waves.
Each satellite
has its own orbit 11,000nautical miles
Objectives:
above the earth.
The aims of the project are:
There are also five
ground stations located around the world
1.To study the
significant
improvement in TEC tomography
resolution.
2.Accurate earthquake warnings are,
that make up the control component.
They track and monitor the GPS
satellites. The user components is the
GPS receivers like the ones you will be
at last, within reach. These predictions
using today.
will come from signals gathered not only
decodes, and processes GPS satellite
at the earth's surface but also far above
signals.
it, in the ionosphere.
Why was it developed and what is it
3. To support research in the field of
tropospheric
products
applicable
to
A receiver detects,
used for?
Navigation systems have been in use
meteorology, with the aim of having an
since prehistoric times.
operational production after 2years.
always been concerned about where they
4. To provide awareness of earth
People have
are, where they are going, and how they
are going to get there and back again.
quake in advance.
Various methods have been used over
GLOBAL
POSITIONING
the course of time from simply leaving
markers along a trial, following a
SYSTEM (GPS)
global
coastline or river, to charting the stars.
positioning system (GPS) was designed
In later years compasses and sextants
to show your exact position on the Earth
where developed. As travel capabilities
anytime, in any weather anywhere. It is
and technology increased the need for
the most advanced system of navigation.
amore accurate system with wider
There are three components to GPS. 1.
coverage also increased. In the early 20th
INTRODUCTION:
the
Proceedings of the International Conference , “Computational Systems and Communication Technology”
8th , MAY 2010 - by Cape Institute of Technology,
Tirunelveli Dt-Tamil Nadu,PIN-627 114,INDIA
century, ground based radio navigation
through the computation of total electron
systems were developed. This system
content (TEC) assuming straight line
was launched into space in 1978 with the
propagation.
first satellite. The last satellite in the
theGPS frequencies and TEC assuming
system was put into orbit in 1994.
straight
The initial purpose for developing this
demonstrate that for GPS frequencies
world encompassing system was to
and for observations in LEO ,the
assist the U.S. armed forces in military
assumption of straight line propogation
operations and weapons systems. It was
(neglecting bending) introduces small
used extensively during operation desert
errors when monitoring the F2 layer.
storm.
The
Since then, new uses are
constantly
being
discovered.
We demonstrate that for
line
second
propogation
algorithm
.We
which
also
Other
assumes straight line propogation ,is
applications include vehicle tracking in
athree dimensional (3-D) inverstion
fleet vehicles, public transportation,
constrained with the horizondal structure
delivery trucks, and courier services,
of a priori electron density fields.As a
emergency vehicle services to improve
priori
response time, mapping and surveying
solutions and the parameterized real time
and scientific monitoring and assaying.
ionospheric specification model(PRISM)
GPS and Ionosphere Relation.
when adjusted with ionosoned data or
fields
we
use
tomographic
Global positioning system (GPS)
ground based GPS vertical TEC maps.
radio occultation signals received by
For both algoriths we calibrate the
slow earth orbit (LEO) satellite provide
occultation data by utilizing observation
information about the global distribution
s from the part of LEO that is closer to
of electron density in the ionosphere. We
the GPS satellite. For inversions we use
examine two radio occultation inversion
dual frequency observational data ( the
algorithms. The first algorithm utilizes
difference
the Abel integral transform, which
observables) which cancel orbit errors (
assumes spherical symmetry of the
without
electron density field.
We test this
determination) and clock errors ( without
algorithm with two approaches, through
requiring synchronous ground data) and
the computation of bending angles and
thus
of
L1
applying
may allow
and
L2
phase
precise
inversions
orbit
to
be
Proceedings of the International Conference , “Computational Systems and Communication Technology”
8th , MAY 2010 - by Cape Institute of Technology,
Tirunelveli Dt-Tamil Nadu,PIN-627 114,INDIA
computed close to real time future .The
ABEL and 3-D constrained algorithms
are validated by statistically comparing 4
days
of
inversions
And L2 carrier phase
 The
C\A
code
(coarse
critical
Acquisition) modulates the L1
frequencies(f0F2)data from a network of
carrier phase .The C\A code is a
45 ionosonde stations and with vertical
repeated 1 MHZ pseudo Random
TEC data from the global network of
Noise (PRN) code .This noise
GPS ground receivers . Globally ,the
like code modulates the L1
Abel inversion approach agrees with the
carrier signal, “spending” the
f0F2 correlative data at 13% rms level,
spectrum
with negligible mean difference . All
bandwidth .The C\A code repeats
tested
inversion
every 1023 bits .There is a
statistically
different C\A code PRN for each
3-D
with
 Three binary codes shift theL1
constrained
approaches
posseses
significant
mean
a
a
1
MHz
.when
SV .GPS satellite are often
compared with the ionosonde data. The
identified by their PRN number ,
vertical TEC correlative comparisons for
the unique identifier for
both the abel and 3-D constrained
pseudo random noise code. The
inversions
C\A that modulates the L1 carrier
are
difference
over
significantly
biased
(~30%)by the electrons above 735 km
each
is the basis for civil SPS.
 The p-Code modulates both the
LEO altitude.
L1 and L2 carrier phase .The pcode is a very long 10 MHz PRN
code .In the anti spoofing (AS)
GPS SATELLITE SIGNALS
 The
SVs
transmit
two
mode of operation ,the p-Code is
microwave carrier signals .The
encrypted
L1
MHZ)
requires a classified AS module
carriers the navigation message
for each receiver channel and is
and the SPS code signals .The L2
for use only by authorized users
frequency(1227.60 MHZ) is used
with cryptographic keys .
frequency(1575.42
to measure the ionospheric delay
by PPS equipped receivers .
into
the
Y-code
 The navigation message also
modulates the L1 –C\A code
Proceedings of the International Conference , “Computational Systems and Communication Technology”
8th , MAY 2010 - by Cape Institute of Technology,
Tirunelveli Dt-Tamil Nadu,PIN-627 114,INDIA
signals .The navigation message
STEC at SIPs. Note that for GPS
is a 50 Hz signal consisting of
data availability reasons a delay
data bits that describe the GPS
of
satellite orbits ,clock corrections
computations has been fixed .
and other system parameters.
Products of day D are computed
at
3
days
day
in
the
D+3.Below
product
is
an
illustration of all the IPPs at a
given instant
 Colors
represent
GPS
representation number
 The STEC is first converted into
VTEC data st SIPs
 Then they are interpolated on a
regular grid to create VTEC
distribution maps over the world.
This is performed with Kalman
filter. IFB and TGD are also
IONOSPHERIC
TOTAL
ELECTRON CONTENT MAP
The VTEC( mapped TEC data is
mapped in 4 steps
 GPS data and satellite orbit data
are
downloaded
external
daily
FTP
from
servers
estimated and appended to the
products created at previous step.
 Finally these data are filtered
with low pass filters to create 15
minute and 1 hour VTEC maps.
MEASURING
THE
TEC
VALUE
(IGS,EUREF,……). The time
samplings of these data are 30
Appleton and Hartee have derived the
seconds
refractive index of the ionosphere ,n and
and
15
minutes
respectively.
 Orbit data are resampled at 30
seconds and GPS and orbit data
are prossesed to compute the
it can be reduced as a function of
electron density N to an accuracy of
better than 1% to the following
n=1-(X/2)=1-(40.3N/f2)
Proceedings of the International Conference , “Computational Systems and Communication Technology”
8th , MAY 2010 - by Cape Institute of Technology,
Tirunelveli Dt-Tamil Nadu,PIN-627 114,INDIA
Knowing
the
refractive
of
Several different types of seismic waves
ionosphere ,it is possible to derive the
move through the ground during an
total no of electrons in ionosphere the
earthquake, the largest scale (and the one
parameter of the ionosphere which
that does most of the moving) is the
produce most of the efforts in the GPS
Rayleigh Wave. This type of wave rolls
signal along the GPS signal trajectory
along the ground, up and down and side-
from each satellite to the observer. This
to-side, in the same way as a wave rolls
integrated no of electrons is commonly
along the ocean. Since the atmospheric
called
density decreases exponentially with
the
index
total
electron
content(TEC).TEC is expressed as a no
altitude, the wave amplitude increases
of electron in a vertical column having a
exponentially as it propagates towards
one square meter cross section and
the
extending all the ways from the GPS
ionosphere, and can reach several tens of
satellite to receiver where
meters for M > 6 earthquakes.
1TECU =1*1016el.m-2
At
GPS signal time delay means that the
frequency acoustic waves interact with
signal s traversing the ionosphere will
the ionospheric plasma and induce
arrive slightly later than they would have
variations in the electronic density
if
they were
traveling
through
ionospheric
heights,
these
low
a
vacuum.By measuring the group path
delay independently at the two widely
spaced
GPS
frequency
L1=f1=1.57542GHz
namely
and
L2=f2=1.2276Ghz The TEC path of the
satellite is calculated using
O
ur format goes beyond this to explore
GPS signals pass through the ionosphere
the possibilities of earthquake detection.
. Various ground-based or satellite
Earthquake Detection
observations
Earthquakes
waves,
perturbing
create
the
acoustic
ionosphere.
have
shown
strong
perturbations
of the ionosphere after earthquakes.
Proceedings of the International Conference , “Computational Systems and Communication Technology”
8th , MAY 2010 - by Cape Institute of Technology,
Tirunelveli Dt-Tamil Nadu,PIN-627 114,INDIA
The observed signals can be explained
making use of thousands of computers to
by the propagation of pressure waves in
make a “virtual super computer”. When
the atmosphere, generated by the ground
implementing the system would be using
displacement near the source or due to
a high performance optical fiber network
Rayleigh waves A one millimetre peak-
which
to-peak displacement at ground level can
measurements
transfers
set up oscillations larger than 100 metres
at an altitude of 150 km. We could also
separate the small total electron content
signal from the very large total electron
content variations related to the daily
variation of the ionosphere."
Piercing
points' shown where signals cross the
the data from the US DOD servers .This
ionosphere. Dual frequency GPS sensors
data is received by local servers .This
have absorbed post seismic disturbance
server then redistributes the data to
on TEC
thousands of idle computer connected to
internet to process the data .The netwok
SYSTEM DESIGN
should have a high speed of transfer as it
would support the real time transfer of
For
harvesting
such
immence
computational power ,we propose the
use of grid computing .By utilizing this
architecture of computing we would be
data to and from server. This project will
use a software to use idle processor time
of computers across the internet to form
Proceedings of the International Conference , “Computational Systems and Communication Technology”
8th , MAY 2010 - by Cape Institute of Technology,
Tirunelveli Dt-Tamil Nadu,PIN-627 114,INDIA
a super computer .This processor will
download information from a remote
FUTURE ENHANCEMENT
sensor which would distribute GPS
satellite data to all the idle computers
across the globe with the software
installed
..
Our future plan is to produce a
simulation software to show the working
of this system using test data .GPS has
been initially installed for various
purposes ,but the
GPS and Grid
computing can be used to provide signs
of the upcoming deviation due to
earthquakes.
Accurate
short-term
forecasts would save lives and enable
businesses to recover sooner With just a
10-minute warning, trains could move
out of tunnels, and people could move to
safer parts of buildings or flee unsafe
buildings. We shall look forward for a
full pledged implementation of this
system
there
by
avoiding
the
reoccurrence of a large no of earth
quakes across the globe
The data would be processed in the
systems across the internet and the result
REFERENCE
will be sent back to the server. We thus
have a super computer capability using
1.SETE@HOME
the idle time of million computer across
2.BERKELEY
OPEN
INFRASTRUCTURE FOR NETWORK
COMPUTING
Proceedings of the International Conference , “Computational Systems and Communication Technology”
8th , MAY 2010 - by Cape Institute of Technology,
Tirunelveli Dt-Tamil Nadu,PIN-627 114,INDIA
3.General Presentation of SPECTRE
5.Calais E. & Minster B.,1995, GPS
Project
detection of ionospheric perturbations
4. Artru J., P. Lognonné et al, 2001,
following
Normal modes modeling of post-seismic
Northridge
ionospheric oscil ations, Geophysical
Research
Research .
.
the
January
Earthquake
17,
1994,
Geophysical