Do you remember the world before GPS? Back when cars never drove onto railroad tracks and people knew how to properly fold maps? Soon, not having indoor positioning systems will seem just as crazy, and you'll wonder how you survived before your phone was able to direct you to the nearest bag of Cheetos with an accuracy measured in centimeters.
The way that GPS satellite works is by transmitting a very precise location signal along with a very precise time signal from space down to Earth. A GPS receiver picks it up, and then uses the speed of light to calculate its distance from the satellite. The receiver then knows that it must be located on the surface of a sphere with a radius of that distance and the satellite as a centerpoint, and by doing this with several satellites all at once, the receiver can pinpoint its location at the intersection of all of those spheres. It's straightforward, simple, and reliable.
A company called Locata has come up with a way to do the exact same thing, except with radio beacons instead of satellites. The beacons are time-synced down to the nanosecond (Locata's trick that makes this whole thing work), and then broadcast their positions, allowing Locata-enabled receivers to pull the same intersecting sphere trick that GPS does to figure out a precise location. The big advantage of using ground-based radio beacons is that the radio signal is strong enough to punch through walls, giving you accuracy on the order of just a couple centimeters both indoors and out.
So, what can centimeter level accuracy do for you? If you're using a Locata-enabled GPS system outdoors, it means that your car will know what lane you're in. Heck, you're car will know if you're in the center of your lane or not. But the really big deal is that Locata works indoors, meaning that you can get all of those handy GPS features in places like stores. Like, let's say you're seriously jonesing for that bag of Cheetos, but you're too tweaked out to find them in the grocery store. With Locata, your phone can direct you to not just the right aisle, but the exact right spot on the exact right shelf.
The Locata tech is already being used by the military and industrial settings, and should be small enough and cheap enough to get stuffed into smartphones within about five years.