It has become more imminent that indoor tracking for first responders has massive potential for emergency situations. It has been a challenge to come up a value-added invention for over a decade. There are several companies focusing on building devices to foster indoor tracking. Analog devices are one of these companies. They have developed a sensor fusion approach to precision location and tracking for first responders.
There are still several challenges to the difficult task of indoor tracking without GPS. Challenges include procedural, environmental, and sensor fusion.
Brighter Sight is keeping close track of this development.
Read more about Analog devices here: