GEO- POSITIONING SYSTEM

One fine morning, you wake up in the middle of dense forest. You do not know where you are? But luckily, you have a FM radio set. Tune the radio, you hear one station feebly. You know the location of that radio station. The maximum range of that FM station is 100 km (say). You must be at the edge of 100 km since the FM signals are weak. Now, you draw a circle with that radio station as the center and 100 km as radius. You must be somewhere on the edge of the circle.

Now try for another station. Luck favors you again. You get second station that too feebly. Now this station as center, you draw second circle of same radius. Now the two circles meet at two points. You may be on any one of the point. Still the information is not enough. Try your luck again. The God of luck is still with you. You get third FM station some what clearly. Draw third circle as usual. The three circles meet at one point. Thank God, that is your location. This is known as 'triangular method'. This technique is used in Geo-positioning system . (GPS)

There are 31 satellites in GPS orbits now. A minimum of 4 satellites will be in contact with GPS receiver you have. Each will send the signals to your receiver and get it back in milliseconds. Then the satellite calculate the distance between you and itself using the time. Next it will draw an imaginary sphere around it using calculated distance as radius. (No circles in space, only spheres)

You can be anywhere on the surface of the sphere. Each satellite will draw its own calculated sphere. Earth sphere can also ,be taken into account. Using the triangulation method you will be located accurately by GPS. That is, all the spheres will meet at one point where you are exactly located.

GPS now have accuracy of 5 meters. It will come down to centimeters in future.
GPS is the boon to modern day navigation.

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DISORDER IS THE "ORDER OF THE DAY"

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