Learn how GPS works in logical steps

The Gps Mobiles : The basis of GPS is "triangulation" from satellites.

1. A "triangle", a distance of GPS receiver measures the travel time of radio signals.
2. In order to measure the travel time, GPS needs very accurate timing, achieved with a few tricks.
3. Together with the distance, you know exactly where the satellites in space. High employment and careful monitoring are the secret.
4. Finally, you need to create a possible delay of the signal experiences as it travels through the atmosphere.

As unlikely as it may sound, is the idea behind the GPS satellites to use as reference points for locations on Earth. That's right, a very measured, very closely with us to distance from three satellites we can "Triangle" our position anywhere in the world. Forget for a moment how our receiver measures this distance. Get later. First consider how distance measurements from three satellites to discover in space.

The Big Idea Geometrically: Suppose we measure our distance from a satellite of 11,000 miles and be found. Know that it 11,000 miles from a particular satellite narrows down all possible forum that we in the universe to the surface of a sphere centered on this satellite and has a radius of 11,000 miles. We tell our distance in half and find that the satellite is 12,000 miles away. This tells us that we not only on the first ball, but we are also a sphere, the 12,000 miles of the second satellite. Or in other words, there is somewhere on the circle where these two areas overlap.

If we make a measurement, say from the third satellite and that it is 13,000 miles from the fact that complement our position below the two points where the sphere intersects the circle 13,000 miles, the interface between the first two balls. So, the three satellites we can reduce our position just two points in space.

To decide which of our two locations where we could make the measurement quarter. But usually one of the two points is a ridiculous answer (or too far from the earth, or at a speed not possible) and can be rejected without a measurement.

A fourth measure is very useful for one reason or another, but tell us more later. Then we'll see how the system measures distances to satellites. But how do you measure the distance of something in circulation in the room? We have now, how long does it take to get a signal from the satellite receiver from us.