Might be off-topic, but anyone know what other techs provide indoor distance tacking/localization other than BLE beacons? WIFI's accuracy is too low.

There are very promising "ultrawideband" solutions (allowing distance to be determined from time of flight of a message rather than signal strength) but the use cases are limited as there is no existing infrastructure. The best that can be done on phones is "sensor fusion" from all available sensors (including wifi and BLE, also integration of motion data) but it requires very extensive mapping of the location in advance. iOS suppports this since a few releases ago but only for locations that have been mapped by Apple so the use cases are rather limited, presumably the mall/airport feature just shown used it.

I worked at a consulting company about a decade ago that designed an indoor tracking system. It could track a device to within a meter, and that was no trivial undertaking. I always have a laugh when I see some startup making a child tracker/pet tracker using iBeacon. You need a large array of radios to track the beacons, you have to model the physics of the building's construction (absorption, Rayleigh scattering, etc), account for multiple floors, and come up with a working algorithm that combines all the RSSI readings to produce a precise location.

It's not all that hard with RFID and the right antenna. It's done extensively in facilities with expensive equipment like refineries.

If you helped implement that system, I'd like to know more.