Vijay Garg
The Global Positioning System (GPS) is a space-based satellite navigation system that provides location and time information in all weather conditions, anywhere on or near the Earth where there is an unobstructed line of sight to four or more GPS satellites. The global positioning system provides a position on the earth’s surface and above with accuracies within about 10meters but within 2m for most of the time. GPS system is very quick and responsive; the position is updated every second in normal low-cost units. Another feature is the precision time, and derived features are speed and direction and track. The system provides critical capabilities to military, civil and commercial users around the world. It is maintained by the United States government and the biggest advantage is that it is freely accessible to anyone with a GPS receiver. The location system is not something new. Land Surveying is a very old activity as well as an important one when it comes to defining the boundaries of a certain piece of land. The importance of this activity is such that there is no room for errors in calculation and measurement. Land surveying in earlier days was done manually and hence the scope for errors was high. However, with the technological advancements, GPS came in to picture and now it is being used with great success in the field of land surveying which comes with the advantage of accuracy and less cost of surveillance. The satellite that sends and receives signals is fully equipped with software protection that reduces mistakes. Data is obtained directly from satellites and the GPS survey equipment does the necessary computation. Sine whole calculation work is being performed by the equipment; hence there is no chance of error. Global Positioning Satellite (GPS) tracking system is a very powerful tool and was originally designed and utilized by the military for a variety of purposes. Military personnel generally used this system to provide location and information of objects or individuals around the world, during navigation in middle of forests, to trace soldiers lost in the forest, for launching missiles and other aerial weapons. GPS has been used in the last decade by civilians as well as to effectively track vehicles and locations, inventory, Alzheimer’s patients, migrating animals, and even pets. Despite its high rate of accuracy, there are some factors that affect the dependability of a GPS system. If the GPS system is of low quality, then the results produced will be one containing errors and will require multiple surveys to get accurate results. The Global Positioning System project was developed in 1973 by America to overcome the limitations of previous navigation systems. It was not a purely new innovation; rather it was an integration of 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 (DOD) and was originally run with 24 satellites and used only for military and aviation purpose. It became fully operational in 1994. Bradford Parkinson, Roger L. Easton, and Ivan A. Getting are credited for inventing it.
During 1973, a meeting of about 12 military officers at the Pentagon discussed the creation of a Defense Navigation Satellite System (DNSS). It was at this meeting that “the real synthesis that became GPS was created.” Later that year, the DNSS program was named Navstar, or Navigation System Using Timing and Ranging. With the individual satellites being associated with the name Navstar, a more fully encompassing name was used to identify the constellation of Navstar satellites, Navstar-GPS, which was later shortened simply to GPS. It was in 1983 after Korean Air Lines Flight 007, a Boeing 747 carrying 269 people, was shot down after straying into the USSR’s prohibited airspace, in the vicinity of Sakhalin and Moneron Islands, a directive was issued making GPS freely available for civilian use, once it was sufficiently developed, as a common good. The first satellite was launched in 1989, and the 24th satellite was launched in 1994. Roger L. Easton is widely credited as the primary inventor of GPS. Over the last decade, the U.S. has implemented several improvements to the GPS service, including new signals for civil use and increased accuracy and integrity for all users, all while maintaining compatibility with existing GPS equipment. GPS modernization has now become an ongoing initiative to upgrade the Global Positioning System with new capabilities to meet growing military, civil, and commercial needs. The program is being implemented through a series of satellite acquisitions, including GPS Block III and the Next Generation Operational Control System (OCX). The U.S. Government continues to improve the GPS space and ground segments to increase performance and accuracy. Global Positioning System is a modern technology that is used worldwide for a majority of purpose that includes military as well as civil uses. GPS has been successfully used for navigation, traffic and shuttle control, location, traffic control as well as locating landing spaces for aircraft at times of emergency. The U.S. Government controls the export of some civilian receivers. All GPS receivers capable of functioning above 18 kilometres (11 mi) altitude and 515 meters per second (1,001 km) or designed, modified for use with unmanned air vehicles like e.g. ballistic or cruise missile systems are classified as munitions (weapons) for which State Department export licenses are required. Global Positioning System is a highly modern device that can track the exact location with the precision of timing as well. A GPS receiver calculates its position by precisely timing the signals sent by GPS satellites high above the Earth. There is a 24 satellite constellation which is in the motion of earth rotation. Each satellite continually transmits messages that include, the time the message was transmitted and satellite position at the time of message transmission. These are the two signals that are the basis of the working of a GPS system. The receiver then uses the messages it receives to determine the transit time of each message and computes the distance to each satellite using the speed of light.
Each of these distances and satellites’ locations defines a sphere. The receiver is on the surface of each of these spheres when the distances and the satellites’ locations are correct. These distances and satellites’ locations are used to compute the location of the receiver using the navigation equations. This location is then displayed, perhaps with a moving map display or latitude and longitude; elevation or altitude information may be included. Many GPS units show derived information such as direction and speed, calculated from position changes. For simple operation, four or more satellites should be visible for the best result. Global Positioning System is used for a wide variety of purpose that includes military as well as civil interests. While originally a military project, GPS is considered a dual-use technology, meaning it has significant military and civilian applications. GPS has become a widely deployed and useful tool for commerce, scientific uses, tracking, and surveillance. GPS’s accurate time facilitates everyday activities such as banking, mobile phone operations, and even the control of power grids by allowing well-synchronized hand-off switching. However, some important uses of GPS technology include Navigation: GPS technology allows soldiers to find objectives, even in the dark or in unfamiliar territory, and to coordinate troop and supply movement. In the armed forces, commanders use the Commanders Digital Assistant and lower ranks use the Soldier Digital Assistant. Even this technology has been widely used to locate soldiers who may get lost in the middle of forest areas or army vehicles that may get confused in foreign territories. Security: GPS technology also acts as a guard against auto and mobile thefts and if GPS chips are installed in the number plates of the cars then these can be easily traced even if these are stolen and being sent to some other region. Also, it is easy to trace lost or stolen mobile phones using GPS technology. Hence GPS is a perfect answer to our security concerns against mobile and vehicle thefts. Target Tracking: One of the major military uses of GPS technology includes target tracking. Various military weapons systems use GPS to track potential ground and air targets before flagging them as hostile. For launching aerial weapons GPS is very important to control the target position for these weapons. These weapon systems pass target coordinates to precision-guided munitions to allow them to engage targets accurately. Military aircraft, particularly in air-to-ground roles, use GPS to find targets. Embedded GPS receivers able to withstand accelerations of 12,000 g or about 118 km/s2 have been developed for use in 155 millimetres (6.1 in) howitzers.
Search and Rescue: Downed pilots can be located faster if their position is known. Also, vehicles that get lost in the mid of forests or in a foreign territory can be easily traced using GPS system. Planes crashing in far-off areas are also traced using this technology as well as for civilian use at the time of natural calamities. Soldiers lost in the mid of forest or marines lost in the sea can all be traced using the technology. Cellular Telephony: Clock synchronization enables time transfer, which is critical for synchronizing its spreading codes with other base stations to facilitate inter-cell handoff and support hybrid GPS/cellular position detection for mobile emergency calls and other applications. The first handsets with integrated GPS launched in the late 1990s. GPS is effectively used for making calls to emergency numbers like 100, 101 etc. which are directed directly using satellite technology to the nearest helpline centre. Geofencing: The geofencing facility that includes vehicle tracking systems, person tracking systems, and pet tracking systems use GPS to locate a vehicle, person, or pet. These devices are attached to the vehicle, person, or the pet collar. Alzheimer disease patients who have a problem in memorizing are also traced using this technology. The application provides continuous tracking and mobile or Internet updates should the target leave a designated area. Also, this technology combined along with motor-vehicles has been used to develop a fully computerized car that doesn’t even need a driver.
Every coin has two sides. If there are benefits then it is also evident that along with that there must be some limitations or disadvantages. The same rule applies to the GPS systems also. There are a lot of advantages that we avail out of this technology, but somewhere around we have to make some compromise also owing to the limitation of this technology. GPS system is a latest technological leap taken, which has brought new features to the communication technology and various other spheres of our life. GPS has many advantages when it comes to useful features like tracking 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 on mobile phones and it again proves to be a huge assistance. Also, it is a great advantage of installing GPS in school or college buses and Cabs for additional security of children and women respectively. But at the same time, there are few limitations too. At times its accuracy can be doubted and also there is a fear of being tracked by other devices which may lead to security concerns.
This satellite-based navigation system is an important tool for military, civil and commercial users. The greatest advantage of this technology is, that it is provided free of cost. There are a lot of advantages associated with this technology. Vehicle tracking systems help in reducing the expenses by referencing customers who do not realize the risks of high speed and importance of fuel. Through evaluation and identifying these drivers, a lot of energy can be saved by reducing the fuel consumption. The low reading on speed meter also ensures fewer accidents. However few other advantages include: Determines the atmosphere’s water content, thereby improving the accuracy of the water forecast.
In traditional methods of survey require a design to make sure that nothing gets in between the measurement line of vision. With the GPS equipment, you do not require an elaborate design of placement and you can select the optimum measurement points despite the terrain of the land. Servicing and marinating vehicles requires a lot of time and money. GPS systems help in saving the end costs when it comes to this. It helps improve mapping as well as tracking skills and also acts as security against vehicular thefts and for locating someone who got lost. Corporate can also reap the advantages of Global Positioning systems. They can keep a check on the productivity of their employees and company as a whole using the GPS technology. GPS can be very effectively used to monitor employees on an individual basis, like their work timings and break timings and can be a highly useful tool to keep a record of the performance of anyone in the firm. If there are so many advantages of GPS then it is evident that there must be a few disadvantages as well as limitations also. Disadvantages of GPS are that it completely relies on receiving satellite signals by radio, so can be prone to nuclear weapons EMP, radio interference, and failed satellites. These are almost unheard of in the current operation, and let us hope they are unlikely. A lot of users who use GPS in vehicles are prone to accidents if they focus more on GPS rather than the road, over that GPS can often land you in a trouble over blocked roads or under construction ones. Another issue is the accuracy. Some potential applications could use even better accuracy, for example as an aid to the blind, automated vehicles and aircraft. Another issue is that the position can be significantly in error occasionally, especially when the number of satellites is restricted. Moreover, there is also a risk of cellular devices being tracked by other cellular one’s which may lead to security issues.
