A Network for Indoor Navigation
From: Popular Science - 12/2104 - page 057
By: Corinne Iozzio and Michael Nuņez

iBeacon, Apple's new communication tool, brings locational awareness indoors.
Unlike GPS, which typically requires an unobstructed path between the device
and satellite, the platform relies on small Bluetooth modules that identify
people's proximity in a given location inside or out. The beacons can then
push tailored content (such as exhibit notes in museums or coupons in a
store) directly to smartphones. Developers have already built hundreds of
applications, including one that lets fans order concessions in baseball
stadiums and another that guides blind passengers through the San Francisco
airport.

Source:
http://bestofwhatsnew.popsci.com/apple-ibeacon

Links:
Understanding iBeacon
http://support.apple.com/en-us/HT202880

iBeacon for Developers
https://developer.apple.com/ibeacon/

What is Apple iBeacon? Here's what you need to know
http://www.zdnet.com/what-is-apple-ibeacon-heres-what-you-need-to-know-7000030109/

San Francisco Airport testing beacon system for blind travelers 
http://www.theverge.com/2014/7/31/5956265/san-francisco-airport-testing-beacon-system-for-blind-travelers

Indoo.rs
http://indoo.rs/