Today's interesting fact has to do with GPS.

GPS stands for Global Positioning System.

GPS is being used by a number of systems these days.

Almost everyone knows about SatNavs and how it makes things easier for drivers to get from one place to another, and they have replaced maps for many.

But there are other systems that use GPS, even though they never move, because of the exact timings that can be obtained from the system.

Three satelites are used to determine the position of the object using GPS, and a fourth satelite then provides the exact time.

That exact time, is used in traffic systems in coordinating traffic lights, in hospitals in coordinating medical machinery, by telephone systems in the masts that send singnals to your mobile telephone.

A recent experiment involving GPS blocking in California by the US Navy caused no end of issues with these systems.

China is producing GPS blockers and these are on sale through the internet throughout the world.