Your Place in the World

You’ve probably used GPS today, in ways you don’t even know about. Of course, your smartphone is a miracle of GPS navigation. It receives data from a network of 31 satellites orbiting about 12,000 miles above us—at least 4 of them are visible from any place on Earth at any time. It uses that data to pinpoint your location to within 10 feet. Pretty amazing. But there are many other ways that GPS impacts our lives. It helps airline pilots and ship captains stay on course. It helps taxis find their fares and military missions find their targets. And it plays important roles in bank transactions and power grids. In fact, because the GPS satellite network is even more stable than the shifting surface of the planet, scientists now use it to track continental plate movement. It shows that Australia moves as fast as fingernails grow, about 3 inches a year, while Hawaii holds the record, moving toward Japan at 4 inches a year. Geodetic surveys correct GPS coordinates for the shifting earth and send updates to our devices on demand. And the whole thing is about to get more precise. The next generation of GPS will use both satellite and ground stations to be accurate to within 1 inch. We’ll need it, as future technologies like driverless cars, delivery drones, and things we can’t even yet imagine, rely on GPS for increasing precision.