Emerging opportunities for localization and tracking [Guest Editorial]

GPS has been a phenomenal success. Simply consider as examples its use in car navigation systems or walking around city streets with the help of a smart phone. However, GPS is unavailable inside buildings, in urban canyons, underground, and underwater. Developing complementary location and tracking technologies for these environments would unleash the use of such capabilities in many applications in the military, public safety, and commercial arenas. Within residences and nursing homes, for example, there is an increasing need for indoor geolocation systems to track people with special needs, the elderly, and children to relieve the need for around-the-clock visual monitoring. Other applications include systems to assist the visually impaired, locate instrumentation and other equipment in hospitals, and track specific items in warehouses. In first responder/public safety and military applications, indoor geolocation systems are needed to monitor inmates in prisons, locate miners trapped in mines, and track/guide first responders and soldiers inside buildings. Given the growing interest in sensor networks and radio frequency identification (RFID) technologies, one can also envision wider-ranging applications such as locating unwanted chemical, biological, or radioactive materials using sensor networks, and tracking specific items such as controlled pharmaceuticals in their containers using RFID tags.