Summary:
My essay is about Global Positioning Systems (GPS).
Global Positioning System (GPS)
Global Positioning System or GPS is a system used to show an individual their position on the globe and navigate to a desired position from their current position. This technology was developed by the United States Department of Defense. To have something to give precise positioning at any point in the world, the Department of Defense had to spend over 12 billion dollars to create an accurate GPS. The GPS has been fine tuned and improved so it is now available on the open market and is very often found in new cars. The technology has revolutionized how people are able to navigate.
The technology behind the Global Positioning System is quite complex but can be broken down into fairly simple terms. A GPS is able to find its position on earth by receiving signals from a minimum of four satellites that are orbiting space. From these satellites, the GPS's position can be determined. The way this is done is by using satellites that are put into space at an elevation of 11,000miles in a precise orbit around the earth. The satellites and the GPS units emit a pseudo random code (PRC). Each PRC is unique to a GPS so that all systems can run on the same wavelength but because the PRC is so random it is nearly impossible for units to get interference from other units. In this manner, a GPS can contact different satellites. Four satellites are used to find the position of a particular GPS. This is very crucial. By using four satellites, the frequency can be tracked to a particular point that is the only spot that all four satellites could hit from their particular locations. This then allows the position of the GPS to be found. The time in each satellite is kept by atomic clocks for accuracy but in case any error is found, a complex geometric equation can eliminate it. This allows for extreme accuracy by the GPS in timing but also in the distance the waves travel so that the exact position of a GPS can be found with minimal error (to less than a centimeter). Accurate timing is needed so that the GPS does not believe it is in a different location, which could present serious problems. Other areas of interference could also affect the accuracy of the GPS but by using different mathematical models and equations, the problems can be nearly eliminated.
Overall there are many used of GPS. Currently, the most common civilian use of GPS is seen in cars. A variation of the system is used to show a car's location and also to give directions to a location. This is very common but other civilian uses are also common. An example is by scientists. Scientists are able to measure Mt. Everest height and conclude that it is slowly getting taller as a glacier is pushing it higher and higher into the atmosphere. This measurement would be impossible if it was not for the technology of GPS. A military use of GPS is seen with the use of smart bombs. In the present war in Iraq, GPS units are put on missiles and bombs and then they can be guided and moved using the GPS unit to accurately hit a certain location. Another military use of GPS in Iraq is used in troop movement. To coordinate positions and movements, troops can use GPS for accurate measurements. Overall, GPS has many helpful applications to the real world.
This is the complete article, containing 581 words
(approx. 2 pages at 300 words per page).
