hi, I am b-tech student i need more information about gps systems
GLOBAL POSITIONING SYSTEMAPPLICABLE TO INDIAN RAILWAYS
Indian Railways is having the world’s largest railway network.
On the other hand it has faced large number of accidents due to the collisions, negligence of the signals etc…
Even though we have got many techniques of preventing these accidents NO METHOD CAN BE MORE EFFECTIVE AS THAT OF GPS.
What is GPS
• GPS: Global positioning system
A network radio navigation system formed from a constellation of minimum of 24 sattelites rotating in six orbitals and their ground stations.
Why GPS here?
To avoid rail accidents
It is highly efficient
The system is highly reliable and informations are highly secured.
main function if GPS is to get the interconnectivity of the various points in the track
Principle of working
• The main principle that is used for the safety of the Indian Railways is that whenever a track there will be vibrations that will be created on the track. These vibrations that are train will move over the produced on the track are dependent on the speed of the train, load or the weight of the train.
• 1. The GP There will be microphones onthe tracks such
that they will constantly note the vibrations that are coming from the train.
2. There will be a software that will convert these vibrations in such a form that they can be compared with the already existing data of the Database .
3. If there will be any problem on the track, bridge etc. such as the removal of the fish plates the vibrations produced from the train will change )the same can be concluded or developed for the bridges also .
COMPONENTS & FUNCTIONS
• Needs critical selection as huge amount of the vibrations of the noises are created that are not possible to get recognized from a large distance.
• Trace the vibrations and sends to DBMS
• Proposed sensor-CARBONSENSORS used in telephone.
Fibre optic wires:
• Transmit the traced vibration data to DBMS quickly.
COMPONENTS & FUNCTIONS
Software and DBMS:
1.Software is the programs that can perfors sometasks that are assigned to them.
2.The DBMS is the Data Base Management Systemwhich can store a huge amount of the data in them.
3.Software converts vibrations from sensors into somegraphical forms and transfer to DBMS which contains pre-loaded data that are analysed in normal conditions.
ONBOARD UNIT DESIGN
1. The on-board unit consists of communication satellite antennae, satellite positioning antennae, the on-board receiver system and communication interface devices, etc.
2. The on-board unit can continuously measure different parameters, tag the data with time and position information, reports irregular conditions.
1. Need of the towers for the transfer of the details and the communication betweenotherestablishments, trains and the satellites.
2. A visual display system to show the actual position of the trains along with other details like visual and audio warning systems.
3. Receivers and the transmitters tuned to proper frequencies and in accordance to the network.
4. The train driver’s cabin must be such that the driver will come to know about the track, weather, bridges and constructional status in advance.
5. Good Communication System. This can be achieved by the use of GPS for the communication.
• Uplink Frequency -5.925 to 6.425 GHz.
• Download Frequency -3.700 to 4.200 GHz.
• may change as per the advancements that are made and the system requirements.
REMEDY THROUGH GPS
• Consider two trains of same or different weights, speeds approaching towards each other in the same tack with GPS Network installed in it.
• The microphone sensors trace the vibrations 35km prior to its arrival.
• As two trains are approaching in the same track the vibrations gets excited.
• This produces emergency signal with alarm and this is transmitted to the control rooms and to loco.
2. Automation in the Work.
3. Reduction in the Stress Levels because of the goodequipments and machinery.
4. Time Delays: As every time the position of the train will be known thus there will not be any time delays.
5. Train Traffic Control: due to continuous monitoring of the trains there will be a good train traffic control.
6. Futuristic method: with this method it is possible to make fully automatic train network which may even not have the driver in it
HOW GPS OVERCOMES
• The implemention time is large and the cost is high to some non-technocrats.
• The survey says that the total loss for our government rates to few hundred crores.
• So just by investing a small sum of this loss, the accidents and the losses can be overcome once for all.
• The benefits and advantages of the proposed method outnumber the problems and disadvantages.
• By considering this method for the most important transport system in India and for the safety the costliest ‘human life’ and the national property can be protected.
• Thus the integration of GPS, sensors along with software systems can be effectively used to provide safety as well as huge income to the Indian Railways.
What is GPS?
GPS is a space based all weather radio navigation system.
Position (geographic), Velocity & Time (PVT) Quickly, Economically And Precisely 24 hours a day, anywhere in the world under the sky
Principle of working using GPS
The basis of GPS technology is precise measurement of time;
Use of orbiting satellite position to find location of receiver by method of resection
GPS data processing software
NAVIGATIONAL DATA, D(t)
L1 (154f or 1575.42 MHz)
L2 (120f or 1227.60 MHz)
GPS Coordinate system
World Geodetic System, 1984 (WGS84)
GPS receivers Positioning Techniques
Ionospheric delay correction is not possible to compute
Weak signal – not available under canopy or under shed
Susceptible to interference
GPS is getting popularas a means for collectionof data
Can be used in any conceivable situation
Under the sky
Where the exact position of any object or phenomena involved.
please send me the seminars report on Global Positioning System.
Global Positioning System
The Global Positioning System (GPS) is a space-based fully functional global navigation satellite system (GNSS) involving satellites and computers that can determine the latitude and longitude of a receiver on Earth by computing the time difference for signals from different satellites to reach the receiver. Thus, it provides reliable location and time information in all weather and at all times and anywhere on or near the Earth when and where there is an unobstructed line of sight to four or more GPS satellites. It is actually a navigation and precise-positioning tool.
What is GLOBAL POSITIONING SYSTEM (GPS)?
The Global Positioning System, commonly known as GPS, is a network of
satellites that determines a ground based user’s specific latitude, longitude, and
altitude. GPS devices have become more integrated in our daily lives through
navigation computers in cars to emergency locators in cellular phones. GPS can
even keep the time accurate on watches and VCRs. Portable GPS receivers are
becoming increasingly popular for young and old alike. For the GPS to work there
are twenty-four satellites in Earth’s orbit.
HISTORY OF GLOBAL POSITIONING SYSTEM (GPS):-
Global positioning grew from the use of radar tracking at the end of World War II when radar stations were placed along the coastlines and inshore for ships and planes to orient themselves. But data and distance were limited and subject to weather and atmosphere interference. With the launch of the Sputnik man-made satellite program by the Soviet Union in the late 1950s, American scientists learned they could precisely locate the satellite by the frequency of its signal.
Navigation is the process of getting from one location to another. This was the what the Global Positioning System was designed for. The GPS system allows us to navigate on water, air, or land. It allows planes to land in the middle of mountains and helps medical evacuation helicopters save precious time by taking the best route.
Global Positioning System
Introduction of GPS
The Global Positioning System (GPS) is a space-based global navigation satellite system (GNSS) that provides location and time information in all weather, anywhere on or near the Earth.
Where there is an unobstructed line of sight to four or more GPS satellites. It is maintained by the United States government and is freely accessible by anyone with a GPS receiver with some technical limitations which are only removed for military users.
The GPS project was developed in 1973 to overcome the limitations of previous navigation systems, integrating ideas from several predecessors, including a number of classified engineering design studies from the 1960s.
GPS was created and realized by the U.S. Department of Defense (USDOD) and was originally run with 24 satellites.
It became fully operational in 1994.
In 1972, the USAF Central Inertial Guidance Test Facility (Holloman AFB), conducted developmental flight tests of two prototype GPS receivers over White Sands Missile Range, using ground-based pseudo-satellites.
In 1978, the first experimental Block-I GPS satellite was launched.
In 1992, the 2nd Space Wing, which originally managed the system, was de-activated and replaced by the 50th Space Wing.
In 1996, recognizing the importance of GPS to civilian users as well as military users, U.S. President Bill Clinton issued a policy directive declaring GPS to be a dual-use system and establishing an Interagency GPS Executive Board to manage it as a national asset.
GPS Receiver clock
If we send out a pulse of sound or radio waves then we can determine resistance of object by dividing the time it took for reply by the speed of sound.
Distance = Speed * Time
Time = Distance / Speed
GPS works on much the same principle. GPS satellite only transmit timing data pulse, GPS receive units, only receive.
Let r4 denote the distance from the valid estimate of GPS receiver position to the fourth satellite and let p4 denote the pseudo range of the fourth satellite.
. Working principle of GPS
How GPS works
GPS signals work in microwaves bands.
They can pass through glass, but are absorbed by water molecules and reflect off concrete, steel and rock.
This means that GPS unit have trouble operating in rain forest, urban jungle, deep canyons, inside automobiles and roads and in heavy snowfalls-among other things.
These environmental obstacles degrade positional accuracy or make it impossible to get a fix on your location.
Global Positioning System
(GPS) technology is a great boon to anyone who has the need to navigate either great or small distances. The Global Positioning System (GPS) is a burgeoning technology, which provides unequalled accuracy and flexibility of positioning for navigation, surveying and GIS data capture. This wonderful navigation technology was actually first available for government use back in the late 1970s. The Global Positioning System (GPS) is a radio based navigation system that gives three dimensional coverage of the Earth, 24 hours a day in any weather conditions throughout the world. The technology seems to be beneficiary to the GPS user community in terms of obtaining accurate data upto about 100 meters for navigation, metre-level for mapping, and down to millimetre level for geodetic positioning. The GPS technology has tremendous amount of applications in Geographical Information System (GIS) data collection, surveying, and mapping.
GEOPOSITIONING -- BASIC CONCEPTS
By positioning we understand the determination of stationary or moving objects. These can be determined as follows:
1. In relation to a well-defined coordinate system, usually by three coordinate values and
2. In relation to other point, taking one point as the origin of a local coordinate system.
GPS - COMPONENTS AND BASIC FACTS
The GPS uses satellites and computers to compute positions anywhere on earth. The GPS is based on satellite ranging. That means the position on the earth is determined by measuring the distance from a group of satellites in space. The basic principles behind GPS are really simple, even though the system employs some of the most high-tech equipment ever developed. In order to understand GPS basics, the system can be categorized into
FIVE logical Steps
Triangulation from the satellite is the basis of the system.
To triangulate, the GPS measures the distance using the travel time of the radio message.
To measure travel time, the GPS need a very accurate clock.
Once the distance to a satellite is known, then we need to know where the satellite is in space.
As the GPS signal travels through the ionosphere and the earth's atmosphere, the signal is delayed.
please send me full seminars report on GPS