Nokia Research has been demonstrating a new system that can accurately track people or objects within a building. It works in a similar way to what GPS does but instead uses a Bluetooth tag along with several bluetooth arrays that are attached to the ceiling. By triangulating where the Bluetooth sensor is it can give an accurate representation as to where an object is.
The image below shows a Parrot drone being tracked. The actual unit has a bluetooth sensor on top and the sensors around the room are used to track it and then the BT sensor feeds back the information to the computer which is then represented on the screen.
The idea behind it could be seen as falling in line with what Google is trying to achieve with its new indoor map service. When a user goes in to a building a smartphone could seamlessly switch between tracking technologies and then track the user more accurately. If you are planning to find somewhere in an airport the bluetooth service could more easily track you and help you to your destination.
Take a look at the video below to see a demonstration of the system working. At the moment there are no formal standards for indoor tracking but Nokia wants to get these in place by 2013.