In Building Navigation

The concept of this device on Discovery News is one of those 'did it really take this long' kind of technologies in my mind. The implications for firefighters and other first responders are obviously significant both for being able to reach the location where they are needed, and for being able to get back out safely. However, my interest is more along these lines: 

She pictures it being an application for a smart device that helps users navigate to specific offices in a large building or a restaurant inside an airport

I can't wait for the day when my iPhone can navigate as well to a location within a building as it can to an address, or for when I can drop a pin when I park my car in an underground garage and be able to navigate directly back to it.

To make GPS work we had to put sattelites in orbit around our planet and allow devices on earth to communicate with them. Doesn't it seem like that should have been harder than developing navigation within a building?