The challenges of inertial navigation on a personal device are that the device orientation changes as the user stand, sits, or lies down. The device also experiences acceleration in many axes. Having the device sort out all these movements and correctly reference them to ground truth would seem to be an interesting challenge - especially when indoor moving sidewalks enable people to change location while standing still (the starting and stopping acceleration and intervening transport time will need to be computed aginst the background activity of a restless human).
I'll be interested to see whether the Internet of Things creates an environment full of navigational beacon locations that become the navigational cues or whether the advanced inertial navigation systems will prove to be more practical.
GT Silicon, an IIT Kanpur incubated company, in collaboration with the KTH Royal Inst. of Technology, has developed a wireless foot-mounted inertial navigation module with an intuitive and significantly simplified dead reckoning interface. GT is targeting applications like First Responder Rescue Systems that are devoid of fixed infrastucture like GPS, WiFi, Maps, etc. More information is available at http://www.gt-silicon.com.
it's not difficult to see the benefit of indoor navigation. Yet, what are the challenges? A year ago, Apple launches iBeacon which is believed to be one of the key technologies to achieve indoor navigation. Is it still the case? What's been done for the past year?