Essay by Neymar1234Junior High, 8th gradeA, October 2014

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Janarth Kulenthiran


Mr. Dallaire

September 19th 2014


What is GPS?

The Global Positioning System is define as a space based satellite navigation that provides location and time information in all weather conditions, anywhere on or near the Earth. The GPS was originally intended for military purposes, but in 1980's the government made it public for the civilian use. The GPS can work in any weather condition and anywhere around the world 24/7.

How does it work?

The Global Positioning system is a network that was made from 30 satellites orbiting the Earth with an altitude approximately 20,000 km. When the signals orbit around the earth it transmits signal information to the earth. The GPS receiver measure the time the signal was transmitted and to the time it was received. The time is the unit in which can tell the distance away from the satellite is, from the earth.

When the distance is their you can determine the user's position at a accurate location and display it on a electronic map.

How does it work to relativity?

The Global Positioning System is a very precise tool that it must take into account a number of affects, some of these are predicted by Einstein's Theory of relativity. (An idea that would revolutionize our understanding of the universe). This theory includes special relativity and general relativity. Special relativity is the theory of space, time and motion and the key is that motion alters time. We see a clock moving slower relative to us, satellite based GPS clocks are moving passed us at 14000 km/h because of special relativity they gradually fall behind us in earth based on receivers at a rate of 7 microseconds/day.

After Einstein's formulated the theory of special relativity he went further and made the...