11-09-2014, 09:47 AM
MODEL POLYTECHNIC COLLEGE
[attachment=67798]
ABSTRACT
GPS satellite can show you exact position on the earth any time, in any weather, no matter where you are! GPS technology has made an impact on navigation and positioning needs with the use of satellites and ground stations the ability to track aircrafts, cars, cell phones, boats and even individuals has become a reality. A system of satellites, computers, and receivers that is able to determine the latitude and longitude of a receiver on Earth by calculating the time difference for signals from The Global Positioning different satellites to reach the receiver. System (GPS) is a worldwide radio-navigation system formed from constellation of 24 satellites and their ground stations. GPS uses these "Man-made stars" as reference points to calculate positions accurate to a matter of meters. In fact, with advanced forms of GPS you can make measurements to better than a centimeter! In a sense it's like giving every square meter on the planet a unique address. GPS receivers have been miniaturized to just a few integrated circuits and so are becoming very economical. And that makes the technology accessible to virtually everyone. Navigation in three dimensions is the primary function of GPS. Navigation receivers are made for aircraft, ships, ground vehicles, and for hand carrying by individuals. Precise positioning is possible using GPS receivers at reference locations providing corrections and relative positioning data for remote receivers. Surveying, geodetic control, and plate tectonic studies are examples. Time and frequency dissemination, based on the precise clocks on board the SVs and controlled by the monitor stations, is another use for GPS. Astronomical observatories, telecommunications facilities, and laboratory standards can be set to precise time signals or controlled to accurate frequencies by special purpose GPS receivers
1. INTRODUCTION OF GPS
GPS (Global Positioning System) is a navigation system composed of a flotilla of satellites put into orbit by the Department of Defense, and their ground stations. With GPS, one can automatically determine the precise location at any point on earth using a ground device that picks up signals from multiple satellites. It works continuously in any part of the world and is available to anyone free of charge. With origins in secret military applications, GPS is now part of everyday life. Dedicated receivers are small and inexpensive, and GPS technology is now found in airplanes, boats, automobiles, cell phones, personal digital assistants, and many other common products.
What attracts us to GPS is:
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 know where they were, at least they knew in what direction they were traveling. 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 travelers 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 make 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 signal 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.
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.
Space Segment
The space segment comprises a network of satellites. The complete GPS space system includes 24 satellites, 11,000 nautical miles above the earth; take 12 hours each to go around the earth once or one orbit. They are orbit in six different planes and 55 degrees inclination. These positions of satellites, we can receive signals from six of them nearly of the time at any point on earth. Satellites are equipped with very precise clocks that keep accurate time to within three nanoseconds. This precision timing is important because the receiver must determine exactly how long it takes for signals to travel from each GPS satellite to receiver. Each satellite contains a supply of fuel and small servo engines so that it can be moved in orbit to correct for positioning errors.
Each satellite contains four atomic clocks. These clocks are accurate to a nanosecond.
Each satellite emits two seperate signals, one for military purposes and one for civilian use.
7. TRACKING
GPS tracking means to trace something or someone with the Global Positioning System. The below diagram illustrates the basic AVL system. It shows the GPS signal arriving from satellite to vehicle. The vehicle location is communicated to the PC (Control Center) via wireless network. But for thousands of years Homosapiens has had the opportunity to observe the movement and general habits of members of his own species as well as of wildlife, particularly by following their tracks. It was a hard and particular unsafe affair. Hence the development of satellite tracking by the Argos consortium was a quantum leap in the human Tracking business. Since 1994 the Global Positioning System has been available for civilian use at no cost. Nowadays GPS makes it available to everyone to track nearly everything. Objects as well as persons can be tracked if they are fitted out with a GPS receiver estimating the respective location. The GPS location data is stored on board of the GPS receiver. Modern GPS tracking systems are able to send such GPS position data from the object directly to a receiving station. A receiving station can be a stationary receiver of a tracking service company (in case of car tracking f. ex.) or provider of a mobile phone company, or just a PC. Nowadays the GPS location data can be also received by small mobile gadgets like laptops, handsets etc. The AVL tracking system consists of a GPS receiver inside the vehicle and a communications link between the vehicle and the control Center as well as pc-based tracking software for dispatch. The communication system is usually a cellular network similar to the one used by your cell phone.
Vehicle Tracking System is a turn-key solution for vehicle owners or fleet operators to determine the location of the vehicle. The solution includes Vehicle tracking unit which is installed in vehicles to collect the vehicle information and Vehicle tracking software which is a web based software application to monitor the current location of the vehicle along with other history details of the vehicle via internat.
The solution allows users to monitor and control the movement of vehicles viz. trip start and completion time, distance traveled, speed etc. at any point of time. This helps in better fleet management by reducing the operating costs and while delivering mobile assets more effectively. The combination of GPS and cellular technology is used to transmit the vehicle data from unit to software.
. ADVANTAGES & DISADVANTAGES OF GPS
Every coin has two sides. The same rule applies to the GPS systems. GPS systems are a latest technological leap taken, which has brought new features to the communication technology. It has many advantages when it comes to tracking things like cars and mobiles or knowing directions while travelling. It is an apt answer to the security concerns we are facing increasingly in today’s age. Cars are stolen and with GPS systems, they can well be traced and returned to the user. Apart from that, GPS can be installed in mobile phones and it again proves to be a huge assistance.
ADVANTAGES
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.
. CONCLUSION
Imagine being an archaeologist on an expedition to the Yucatan Peninsula in Mexico. After preparing for your trip for months, you are certain that somewhere close by are the ruins of villages once populated by Mayan Indians. The forest is dense, the sun is hot, and the air is humid. The only way you can record where you have been, or find your way back to civilization, is by using the almost magic power of your GPS receiver. Or let's suppose you are an oceanographer for the International Ice Patrol. You may be responsible for finding icebergs that form in the cold waters of the North Atlantic Ocean. Some of these icebergs are 50 miles long. They are a major threat to the ships that travel those waters, and more than 300 of them form every winter. Using a GPS receiver, you are able to help ships avoid disaster by zeroing in on the position of the icebergs and notifying ship captains of their locations, perhaps avertingdisaster.There will probably be a time soon when every car on the road can be equipped with a GPS receiver, including a video screen installed in the dashboard. Theindash monitor will be a full-color display showing your location and a map of the roads around you. It will probably monitor your car's performance and your car phone as well. Systems as amazing as this one are already being tested on highways in the United States. GPS is rapidly changing the way people are finding their way around the earth. Whether it is for fun, saving lives, getting there faster or whatever use you can dream of, GPS navigation is becoming more common every day. GPS will figure in history alongside the development of the sea-going chronometer. This device enabled seafarers to plot their course to an accuracy that greatly encouraged maritime activity, and led to the migration explosion of the nineteenth century. GPS will affect mankind in the same way. There are myriad applications that will benefit us individually and collectively.
[attachment=67798]
ABSTRACT
GPS satellite can show you exact position on the earth any time, in any weather, no matter where you are! GPS technology has made an impact on navigation and positioning needs with the use of satellites and ground stations the ability to track aircrafts, cars, cell phones, boats and even individuals has become a reality. A system of satellites, computers, and receivers that is able to determine the latitude and longitude of a receiver on Earth by calculating the time difference for signals from The Global Positioning different satellites to reach the receiver. System (GPS) is a worldwide radio-navigation system formed from constellation of 24 satellites and their ground stations. GPS uses these "Man-made stars" as reference points to calculate positions accurate to a matter of meters. In fact, with advanced forms of GPS you can make measurements to better than a centimeter! In a sense it's like giving every square meter on the planet a unique address. GPS receivers have been miniaturized to just a few integrated circuits and so are becoming very economical. And that makes the technology accessible to virtually everyone. Navigation in three dimensions is the primary function of GPS. Navigation receivers are made for aircraft, ships, ground vehicles, and for hand carrying by individuals. Precise positioning is possible using GPS receivers at reference locations providing corrections and relative positioning data for remote receivers. Surveying, geodetic control, and plate tectonic studies are examples. Time and frequency dissemination, based on the precise clocks on board the SVs and controlled by the monitor stations, is another use for GPS. Astronomical observatories, telecommunications facilities, and laboratory standards can be set to precise time signals or controlled to accurate frequencies by special purpose GPS receivers
1. INTRODUCTION OF GPS
GPS (Global Positioning System) is a navigation system composed of a flotilla of satellites put into orbit by the Department of Defense, and their ground stations. With GPS, one can automatically determine the precise location at any point on earth using a ground device that picks up signals from multiple satellites. It works continuously in any part of the world and is available to anyone free of charge. With origins in secret military applications, GPS is now part of everyday life. Dedicated receivers are small and inexpensive, and GPS technology is now found in airplanes, boats, automobiles, cell phones, personal digital assistants, and many other common products.
What attracts us to GPS is:
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 know where they were, at least they knew in what direction they were traveling. 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 travelers 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 make 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 signal 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.
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.
Space Segment
The space segment comprises a network of satellites. The complete GPS space system includes 24 satellites, 11,000 nautical miles above the earth; take 12 hours each to go around the earth once or one orbit. They are orbit in six different planes and 55 degrees inclination. These positions of satellites, we can receive signals from six of them nearly of the time at any point on earth. Satellites are equipped with very precise clocks that keep accurate time to within three nanoseconds. This precision timing is important because the receiver must determine exactly how long it takes for signals to travel from each GPS satellite to receiver. Each satellite contains a supply of fuel and small servo engines so that it can be moved in orbit to correct for positioning errors.
Each satellite contains four atomic clocks. These clocks are accurate to a nanosecond.
Each satellite emits two seperate signals, one for military purposes and one for civilian use.
7. TRACKING
GPS tracking means to trace something or someone with the Global Positioning System. The below diagram illustrates the basic AVL system. It shows the GPS signal arriving from satellite to vehicle. The vehicle location is communicated to the PC (Control Center) via wireless network. But for thousands of years Homosapiens has had the opportunity to observe the movement and general habits of members of his own species as well as of wildlife, particularly by following their tracks. It was a hard and particular unsafe affair. Hence the development of satellite tracking by the Argos consortium was a quantum leap in the human Tracking business. Since 1994 the Global Positioning System has been available for civilian use at no cost. Nowadays GPS makes it available to everyone to track nearly everything. Objects as well as persons can be tracked if they are fitted out with a GPS receiver estimating the respective location. The GPS location data is stored on board of the GPS receiver. Modern GPS tracking systems are able to send such GPS position data from the object directly to a receiving station. A receiving station can be a stationary receiver of a tracking service company (in case of car tracking f. ex.) or provider of a mobile phone company, or just a PC. Nowadays the GPS location data can be also received by small mobile gadgets like laptops, handsets etc. The AVL tracking system consists of a GPS receiver inside the vehicle and a communications link between the vehicle and the control Center as well as pc-based tracking software for dispatch. The communication system is usually a cellular network similar to the one used by your cell phone.
Vehicle Tracking System is a turn-key solution for vehicle owners or fleet operators to determine the location of the vehicle. The solution includes Vehicle tracking unit which is installed in vehicles to collect the vehicle information and Vehicle tracking software which is a web based software application to monitor the current location of the vehicle along with other history details of the vehicle via internat.
The solution allows users to monitor and control the movement of vehicles viz. trip start and completion time, distance traveled, speed etc. at any point of time. This helps in better fleet management by reducing the operating costs and while delivering mobile assets more effectively. The combination of GPS and cellular technology is used to transmit the vehicle data from unit to software.
. ADVANTAGES & DISADVANTAGES OF GPS
Every coin has two sides. The same rule applies to the GPS systems. GPS systems are a latest technological leap taken, which has brought new features to the communication technology. It has many advantages when it comes to tracking things like cars and mobiles or knowing directions while travelling. It is an apt answer to the security concerns we are facing increasingly in today’s age. Cars are stolen and with GPS systems, they can well be traced and returned to the user. Apart from that, GPS can be installed in mobile phones and it again proves to be a huge assistance.
ADVANTAGES
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.
. CONCLUSION
Imagine being an archaeologist on an expedition to the Yucatan Peninsula in Mexico. After preparing for your trip for months, you are certain that somewhere close by are the ruins of villages once populated by Mayan Indians. The forest is dense, the sun is hot, and the air is humid. The only way you can record where you have been, or find your way back to civilization, is by using the almost magic power of your GPS receiver. Or let's suppose you are an oceanographer for the International Ice Patrol. You may be responsible for finding icebergs that form in the cold waters of the North Atlantic Ocean. Some of these icebergs are 50 miles long. They are a major threat to the ships that travel those waters, and more than 300 of them form every winter. Using a GPS receiver, you are able to help ships avoid disaster by zeroing in on the position of the icebergs and notifying ship captains of their locations, perhaps avertingdisaster.There will probably be a time soon when every car on the road can be equipped with a GPS receiver, including a video screen installed in the dashboard. Theindash monitor will be a full-color display showing your location and a map of the roads around you. It will probably monitor your car's performance and your car phone as well. Systems as amazing as this one are already being tested on highways in the United States. GPS is rapidly changing the way people are finding their way around the earth. Whether it is for fun, saving lives, getting there faster or whatever use you can dream of, GPS navigation is becoming more common every day. GPS will figure in history alongside the development of the sea-going chronometer. This device enabled seafarers to plot their course to an accuracy that greatly encouraged maritime activity, and led to the migration explosion of the nineteenth century. GPS will affect mankind in the same way. There are myriad applications that will benefit us individually and collectively.