We at GiPStech are developing a solution based on anomalies of geomagnetic field (similar to Indoor Atlas) integrated with RF (wifi and beacons) to get precise to 1 meter / 3 ft with little or no infrastructure :-)
In the meantime, depending on the localization accuracy you need you can resort to wifi tracking (10-15 meters) or Low Energy Bluethooth beacons (2-5 meters, perhaps adopting the Apple protocol called "iBeacons"). Some solutions are available "off the shelves" in the market, look at Indoo.rs or Estimote or Loctronix, but there are many others