The document discusses the Global Positioning System (GPS). It describes the three segments of GPS - the space segment consisting of satellites, the control segment which monitors the satellites and uploads navigation data, and the user segment which receives signals from satellites using a receiver. It provides details on satellite orbits, atomic clocks, signal generation, navigation messages, and how trilateration is used to determine user position from multiple satellite ranges.
Brilliant Lecture delivered to me in Alagappa Engineering college Workshop.
The Global Positioning System (GPS) is a satellite
based radio navigation system provided by the
United States Department of Defence. It gives
unequaled accuracy and flexibility in positioning
for navigation, surveying and GIS data collection.
Brilliant Lecture delivered to me in Alagappa Engineering college Workshop.
The Global Positioning System (GPS) is a satellite
based radio navigation system provided by the
United States Department of Defence. It gives
unequaled accuracy and flexibility in positioning
for navigation, surveying and GIS data collection.
Relativistic Effect in GPS Satellite and Computation of Time Error Vedant Srivastava
The satellites are the integral part of our life. In current scenario, our planet is covered with
thousands of satellites. These satellites covers every aspect of communication like- navigation,
telecommunication, television broadcasting, satellite imaginary, military communications,
Space Station, Earth's weather and climate etc. The small time delay in clock implemented in
satellites cause large delay in propagating signal and it leads to tremendous loss in
communication. This Project basically deals with detection and computation of time error on
satellite clock due to relativistic effect. The time delay is based on both special and general
relativity postulated by Albert Einstein in 1905 and 1915. The detection and computation had
been done by presenting the simulations in the MATLAB environment. The focus of project is
specially GPS satellites due to the need of better and reliable navigation system in current
scenario. Using the Simulink Environment in MATLAB a P code and C/A code have generated
and tested. These code contains timing signal and synchronization signal for GPS satellites.
Synchronizing time with precise time calculation on GPS receivers, system simulation in
MATLAB from GPS satellite transmitter to receiver will be discussed here. The atomic clock
is also discussed here which is used to measure the time delay with high level of precision
(around 10 nano-second) in satellites. Satellite Tool Kit (STK) Software a package
from Analytical Graphics, Inc. is also used in the project to model the satellite and its orbit
around the planet earth. It provides very high graphics simulation and modelling. It allows
engineers and scientists to perform complex analyses of all the physical parameters necessary
for satellite designing and communication.
Basic concept, System Architecture, GPS and GLONASS Overview, Satellite Navigation, Time and GPS, User Position and Velocity Calculations, GPS Satellite Constellation, Operation Segment, User Receiving Equipment, Space Segment Phased Development, GPS Aided Geo augmented Navigation (GAGAN) Architecture.
Relativistic Effect in GPS Satellite and Computation of Time Error Vedant Srivastava
The satellites are the integral part of our life. In current scenario, our planet is covered with
thousands of satellites. These satellites covers every aspect of communication like- navigation,
telecommunication, television broadcasting, satellite imaginary, military communications,
Space Station, Earth's weather and climate etc. The small time delay in clock implemented in
satellites cause large delay in propagating signal and it leads to tremendous loss in
communication. This Project basically deals with detection and computation of time error on
satellite clock due to relativistic effect. The time delay is based on both special and general
relativity postulated by Albert Einstein in 1905 and 1915. The detection and computation had
been done by presenting the simulations in the MATLAB environment. The focus of project is
specially GPS satellites due to the need of better and reliable navigation system in current
scenario. Using the Simulink Environment in MATLAB a P code and C/A code have generated
and tested. These code contains timing signal and synchronization signal for GPS satellites.
Synchronizing time with precise time calculation on GPS receivers, system simulation in
MATLAB from GPS satellite transmitter to receiver will be discussed here. The atomic clock
is also discussed here which is used to measure the time delay with high level of precision
(around 10 nano-second) in satellites. Satellite Tool Kit (STK) Software a package
from Analytical Graphics, Inc. is also used in the project to model the satellite and its orbit
around the planet earth. It provides very high graphics simulation and modelling. It allows
engineers and scientists to perform complex analyses of all the physical parameters necessary
for satellite designing and communication.
Basic concept, System Architecture, GPS and GLONASS Overview, Satellite Navigation, Time and GPS, User Position and Velocity Calculations, GPS Satellite Constellation, Operation Segment, User Receiving Equipment, Space Segment Phased Development, GPS Aided Geo augmented Navigation (GAGAN) Architecture.
Global Positioning System (GPS) is the only system today able to show one’s own position on the earth any time in any weather, anywhere. This paper addresses this satellite based navigation system at length. The different segments of GPS viz. space segment, control segment, user segment are discussed. In addition, how this amazing system GPS works, is clearly described. The various errors that degrade the performance of GPS are also included. DIFFERENTIAL GPS, which is used to improve the accuracy of measurements, is also studied. The need, working and implementation of DGPS are discussed at length. Finally, the paper ends with advanced application of GPS.
Palestine last event orientationfvgnh .pptxRaedMohamed3
An EFL lesson about the current events in Palestine. It is intended to be for intermediate students who wish to increase their listening skills through a short lesson in power point.
The French Revolution, which began in 1789, was a period of radical social and political upheaval in France. It marked the decline of absolute monarchies, the rise of secular and democratic republics, and the eventual rise of Napoleon Bonaparte. This revolutionary period is crucial in understanding the transition from feudalism to modernity in Europe.
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The Roman Empire A Historical Colossus.pdfkaushalkr1407
The Roman Empire, a vast and enduring power, stands as one of history's most remarkable civilizations, leaving an indelible imprint on the world. It emerged from the Roman Republic, transitioning into an imperial powerhouse under the leadership of Augustus Caesar in 27 BCE. This transformation marked the beginning of an era defined by unprecedented territorial expansion, architectural marvels, and profound cultural influence.
The empire's roots lie in the city of Rome, founded, according to legend, by Romulus in 753 BCE. Over centuries, Rome evolved from a small settlement to a formidable republic, characterized by a complex political system with elected officials and checks on power. However, internal strife, class conflicts, and military ambitions paved the way for the end of the Republic. Julius Caesar’s dictatorship and subsequent assassination in 44 BCE created a power vacuum, leading to a civil war. Octavian, later Augustus, emerged victorious, heralding the Roman Empire’s birth.
Under Augustus, the empire experienced the Pax Romana, a 200-year period of relative peace and stability. Augustus reformed the military, established efficient administrative systems, and initiated grand construction projects. The empire's borders expanded, encompassing territories from Britain to Egypt and from Spain to the Euphrates. Roman legions, renowned for their discipline and engineering prowess, secured and maintained these vast territories, building roads, fortifications, and cities that facilitated control and integration.
The Roman Empire’s society was hierarchical, with a rigid class system. At the top were the patricians, wealthy elites who held significant political power. Below them were the plebeians, free citizens with limited political influence, and the vast numbers of slaves who formed the backbone of the economy. The family unit was central, governed by the paterfamilias, the male head who held absolute authority.
Culturally, the Romans were eclectic, absorbing and adapting elements from the civilizations they encountered, particularly the Greeks. Roman art, literature, and philosophy reflected this synthesis, creating a rich cultural tapestry. Latin, the Roman language, became the lingua franca of the Western world, influencing numerous modern languages.
Roman architecture and engineering achievements were monumental. They perfected the arch, vault, and dome, constructing enduring structures like the Colosseum, Pantheon, and aqueducts. These engineering marvels not only showcased Roman ingenuity but also served practical purposes, from public entertainment to water supply.
2024.06.01 Introducing a competency framework for languag learning materials ...Sandy Millin
http://sandymillin.wordpress.com/iateflwebinar2024
Published classroom materials form the basis of syllabuses, drive teacher professional development, and have a potentially huge influence on learners, teachers and education systems. All teachers also create their own materials, whether a few sentences on a blackboard, a highly-structured fully-realised online course, or anything in between. Despite this, the knowledge and skills needed to create effective language learning materials are rarely part of teacher training, and are mostly learnt by trial and error.
Knowledge and skills frameworks, generally called competency frameworks, for ELT teachers, trainers and managers have existed for a few years now. However, until I created one for my MA dissertation, there wasn’t one drawing together what we need to know and do to be able to effectively produce language learning materials.
This webinar will introduce you to my framework, highlighting the key competencies I identified from my research. It will also show how anybody involved in language teaching (any language, not just English!), teacher training, managing schools or developing language learning materials can benefit from using the framework.
The Art Pastor's Guide to Sabbath | Steve ThomasonSteve Thomason
What is the purpose of the Sabbath Law in the Torah. It is interesting to compare how the context of the law shifts from Exodus to Deuteronomy. Who gets to rest, and why?
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It is possible to hide or invisible some fields in odoo. Commonly using “invisible” attribute in the field definition to invisible the fields. This slide will show how to make a field invisible in odoo 17.
Operation “Blue Star” is the only event in the history of Independent India where the state went into war with its own people. Even after about 40 years it is not clear if it was culmination of states anger over people of the region, a political game of power or start of dictatorial chapter in the democratic setup.
The people of Punjab felt alienated from main stream due to denial of their just demands during a long democratic struggle since independence. As it happen all over the word, it led to militant struggle with great loss of lives of military, police and civilian personnel. Killing of Indira Gandhi and massacre of innocent Sikhs in Delhi and other India cities was also associated with this movement.
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2. Global Positioning System (GPS)
The concept of satellite position fixing commenced with the launch of the first Sputnik
satellite by the USSR in October 1957.
This was rapidly followed by the development of the Navy Navigation Satellite System
(NNSS) by the US Navy referred as the Transit system.
In 1973, the US Department of Defense (DoD) commenced the development of NAVSTAR
(Navigation System with Time and Ranging) Global Positioning System (GPS), and the first
satellites were launched in 1978.
The accuracies that may be obtained from the system depend on the degree of access
available to the user, the sophistication of his/her receiver hardware and data processing
software, and degree of mobility during signal reception.
The GPS navigation system relies on satellites that continuously broadcast their own
position in space and in this the satellites may be thought of as no more than control
stations in space.
Theoretically, a user who has a clock, perfectly synchronized to the GPS time system, is
able to observe the time delay of a GPS signal from its own time of transmission at the
satellite, to its time of detection at the user’s equipment.
The time delay, multiplied by the mean speed of light, along the path of the transmission
from the satellite to the user equipment, will give the range from the satellite at its known
position, to the user.
If three such ranges are observed simultaneously, there is sufficient information to
compute the user’s position in three-dimensional space, rather in the manner of a three-
dimensional trilateration.
The false assumption in all this is that the user’s receiver clock is perfectly synchronized
with the satellite clocks.
3. In practice, although the satellite clocks are almost perfectly synchronized to the GPS
time system, the user clock will have an error or offset.
So the user is not directly able to measure the range to a particular satellite, but only
the ‘pseudo-range’, i.e. the actual range with an unknown, but instantaneously fixed
offset. This is the clock error times the speed of light.
There are four unknown parameters to be solved for in the navigation solution, the
three coordinates of user position and the receiver clock offset.
A four parameter solution therefore requires simultaneous observations to four
satellites. At least four satellites must be visible at all times, to any observer, wherever
he/she may be on or above the surface of the Earth.
Not only must at least four satellites be visible but also they, or the best four if there
are more, must be in a good geometric arrangement with respect to the user.
GPS SEGMENTS
The GPS system can be broadly divided into three segments:
(i) The space segment,
(ii) The control segment and
(iii) the user segment.
4. The Space segment
The space segment is composed of satellites. The constellation consists of 27 satellites
including spares.
The satellites are in almost circular orbits, at a height of 20,200 km above the Earth or
about three times the radius of the Earth and with orbit times of just under 12 hours.
The six orbital planes are equally spaced, and are
inclined at 55° to the equator.
Individual satellites may appear for up to five hours
above the horizon.
The system has been designed so that at least four satellites will always be in view at
least 15° above the horizon.
The original planned GPS constellation: 24 satellites in 6 orbital planes, at 55 °inclination and 20, 200 km
altitude with 12-hour orbits (courtesy Leica Geosystems)
5. The GPS satellites weigh, when in final orbit, approximately 850 kg. The design life of
the satellites is 7.5 years but they carry 10 years’ worth of propulsion consumables.
Two sun-seeking single degree of freedom solar arrays, which together cover over 7m2
provide the electrical power. Power is retained during eclipse periods by three nickel-
cadmium batteries.
Reaction wheels control the orientation and position of the satellite in space. Thermal
control louvers, layered insulation and thermostatically controlled heaters control the
temperature of this large satellite.
The satellite is built with a rigid body of aluminium boarded honeycomb panels.
The satellite may be ‘navigated’ to a very limited extent in space with small hydrazine
jets.
There are two small trim thrusters and 20 even smaller attitude control thrusters.
Antennae transmit the satellite’s signals to the user.
Each satellite carries two rubidium and two caesium atomic clocks to ensure precise
timing.
As far as the user is concerned, each GPS satellite broadcasts on two L Band carrier
frequencies.
L1 = 1575.42 MHz (10.23 × 154) and L2 = 1227.6 MHz (10.23 × 120).
The carriers are phase modulated to carry two codes, known as the P code or Precise
code or PPS (Precise Positioning Service) and the C/A code or Course/Acquisition code or
SPS (Standard Positioning Service).
7. The C/A code has a ‘chipping rate’, which is a rate of phase modulation, of 1.023 × 106
bits/sec and the code repeats every millisecond. This means that the sequence that
makes up the C/A code is only 1023 bits long. Multiplied by the speed of light, each bit is
then 293 m long and the whole code about 300 km.
By contrast, the P code chips at 10.23 × 106 bits/sec and repeats every 267 days
although each satellite only uses a seven-day segment of the whole code. The P code is
thus about 2.4 × 1014 bits long.
Without prior knowledge of its structure, the P code will appear as Pseudo Random
Noise (PRN). This means that it is relatively easy for the user’s equipment to obtain lock
onto the C/A code, since it is short, simple and repeats 1000 times a second.
Without knowledge of the P code, it is impossible in practice to obtain lock because the
P code is so long and complex.
This is the key to selective access to the GPS system. Only those users approved by the
US DoD will be able to use the P code.
A 50 Hz data stream that contains the following information further modulates each
code:
The satellite ephemeris, i.e. its position in space with respect to time
Parameters for computing corrections to the satellite clock
The Hand OverWord (HOW) for time synchronization that allows the user with access to
the P code to transfer from the C/A to P code
Information on other satellites of the constellation, including status and ephemerides
8. The Control Segment
The satellite navigation message, which describes the satellite positions, is
uploaded to the satellites by the Operational Control Segment (OCS). The OCS operates
as three elements:
• Monitor stations at Ascension Island, Diego Garcia, Kwajalein and Hawaii
• A master control station at Colorado Springs, USA
• An upload station at Vandenberg Air Force Base, USA
The monitor stations are remote, unmanned stations, each with a GPS receiver, a
clock, meteorological sensors, data processor and communications. Their functions are
to observe the broadcast satellite navigation message and the satellite clock errors and
drifts.
The data is automatically gathered and processed by each monitor station and is
transmitted to the master control station.
By comparing the data from the various monitor stations the master control station
can compute the errors in the current navigation messages and satellite clocks, and so
can compute updated navigation messages for future satellite transmission.
These navigation messages are passed to the upload station and are in turn processed
for transmission to the satellites by the ground antenna.
The monitor stations then receive the updated navigation messages from the
satellites and so the data transmission and processing circle is complete.
The master control station is also connected to the time standard of the US Naval
Observatory in Washington, DC.
In this way, satellite time can be synchronized and data relating it to universal time
transmitted.
Other data regularly updated are the parameters defining the ionosphere, to facilitate
the computation of refraction corrections to the distances measured.
9. The User Segment
The user segment consists essentially of a portable receiver/processor with power supply
and an omnidirectional antenna.
The processor is basically a microcomputer containing all the software for processing the
field data.
Handheld GPS Receiver