Selected and re-edited by FauSham from many resources as Informative sources for MFM Reader.
Did u know that, our GPS use Trilateration geometric equation to calculate our coordinate?

But I like to share with all MFM's member.....
What is Trilateration?
The measurement of a series of distances between points on the surface of the earth, for the purpose of establishing relative positions of the points in surveying.
Trilateration is a method for determining the intersections of three sphere surfaces given the centers and radii of the three spheres.

See this diagram.....

We start with the equations for the three spheres


and

We need to find a point located at (x, y, z) that satisfies all three equations.
First we subtract the second equation from the first and solve for x:

Substituting this back into the formula for the first sphere produces the formula for a circle, the solution to the intersection of the first two spheres:

Substituting :


Now that we have the x- and y-coordinates of the solution point, we can simply rearrange the formula for the first sphere to find the z-coordinate:

All this calculation has been made and use by our GPS to do tracking


Diagram credit: Wikipedia