Twenty-four satellites orbit 11000 ...

Twenty-four satellites orbit 11000 nautical miles above the earth in a widely dispersed constellation, constantly transmitting their positions, identities and times of signal broadcasts (clock within the satellites are synchronized with each other and with a master atomic clock in succession the ground).

Back forward terra firma, a survey vehicle zips down the high, way at normal get ons It is equipped with an impressive arsenal of sensors, lasers, accelerometers and inertial navigation units, enabling it to receive signals beamed from space. Performing high-precision computations, the "Automated Road Analyzer" automatically descrys cracks, potholes and other road deficiencys -- while simultaneously mapping and logging the condition of signs, highway markers and right of ways.

While the above scenario goods more like a scene from "Star Trek" or "Space 1999" than the lead story in today's newspaper, the Global Positioning regularity (GPS) satellite constellation was actually created at the Department of Defense