Christian Science Monitor – Passcode
8 January 2016
By Joe Uchill

From a command center at Schriever Air Force Base, about 10 miles outside Colorado Springs, Colo., seven 20-something airmen are responsible for safeguarding global financial markets, international commerce, the US power grid, all telecommunications, and ensuring that Uber drivers everywhere can find even the most out-of-the-way restaurants.

The highly trained military personnel with Air Force Space Command protect the 31 satellites the US relies on to provide access to terrestrial navigation. Their office is the control center for the Global Positioning System (GPS) that some 4 billion people around the world use daily, making it possibly the largest humanitarian service provided by any one nation.

Most people think of GPS as the ubiquitous yet invisible system that moves the dot on Google maps. But the massive network of satellites and countless receivers do much more. GPS signals provide any object containing a receiver chip with continuous and precise time information from the satellites’ atomic clocks. Any task that requires precision timing (including synchronization telecommunications) or a record of high-speed transactions (including Wall Street trades) uses GPS.