How does a GPS (Global Positioning System) work?

[peachey]

GPS stand for Global Positioning System. Here is a definiation of the system.

A system of satellites around the Earth that broadcast the time via radio signals based on an internal atomic clock. GPS devices can receive the signals from multiple satellites, and by measuring the time it took the signal to arrive they can determine your current position on the Earth

How does this really work?
Once the signal is put to the satellites it is then transmitted to the wireless network that is closes to the area you are in or where you have set the gps for the location that you would like to go. There are thousands of wireless networks around the world to be able to track a gps. They are put on towers, underground, and other places so that the signal will be pick up.

This is basic information about the gps and how it works. To find out more you can search the internet. There is alot of information on gps and the diffrent systems that is available. [/quote]

[hassen1]

If I may be permited to add to what Prof. peachey had said above, please read below:

Since man set out on journey outside his home village, he was interested in how to get home and to know where he was throughout his journey. The invention of the magnetic compass was a huge success and in co-ordination with stars and accurate time keeping, navigation became more reliable. However, this combination of science and art form took many lessons and much practice to master. During the Second World War electronic devices surfaced. They helped the air and sea navigators. In 1978 the U.S. launched its first navigational satellite and by 1994 it had 24 of these satellites in orbit. Initially it was purely for military purposes; however the system is now available at no cost for civilian use. The Global Positioning System or GPS works with these 24 satellites transmitting signals. Our GPS receiver then picks up three or more of these signals and triangulates on them. The system is extremely accurate; usually within 3 metres anywhere on earth. One can even tell which side of the highway he is on!

[peachey]

Thanks for the additional information on the GPS...

We use to live at an airport and when they GPS was really getting out they put an tower near buy us then had to put in the tracking, for the area around us. I was able to watch them put this in and set up a position for that area. Was interesting on how they did all of that for a small radio you have will tell you exactly where you are or how to get there..

[rowenahere]

It is based on "Triangulation" , from satellites, a layman term.

Correct term would be "trilateration", a method of determining the relative positions of objects using the geometry of triangles.

For "Triangulation," a GPS receiver measures distance using the travel time of radio signals, which requires accurate timing.

Besides, the distance, one needs to know the location of the satellites in space via high orbits and careful monitoring.

Then, to make corrections for any signal delays that might occur during the travel in atmosphere.