Anyone who has utilized their cell phone and a GPS app or a GPS device to find their way knows there are some problems with the technology. It isn’t really the technology’s fault, either. If using the app or GPS device indoors, you’ll likely find the device unable to receive signal from the GPS satellites thanks to the structure of the building, or competition from competing signals. But who needs to use a GPS device indoors anyway? When you really think about it, a GPS device would really come in handy in large, unfamiliar buildings.
GPS for indoor spaces is currently being developed and has for at least the past decade. However, all of the other types of signals that share the air have been causing problems: wi-fi, cellular, ultrasound, etc. All of these additional signals have made it tricky to create an accurate indoor GPS device. Although the GPS device in your car might not be totally accurate, like when you are looking for a restaurant and you reach the driveway ten feet or so before your GPS tells you to turn, it isn’t that big of a problem. You can use your common sense to see that you are close and begin looking for the sign of the establishment. Let’s say you are trying to visit a loved one in an unfamiliar hospital. Imagine wandering the hallways, being guided by your GPS device, and having it be 10 or more feet off. You might end up in the wrong hallway, never finding your way to the correct room.
Researchers at Duke University together with the Egypt-Japan University of Science and Technology are currently working on software for smartphones that actually use the different types of signals that normally compete with standard GPS apps. They have called it the UnLoc system, or unsupervised indoor localization, and it works by collecting signal data from cellular radios, wi-fi antennas, gyroscopes, compasses, and accelerometers.
UnLoc tags each signal as a virtual landmark. For example, the system can determine you are on an elevator by the direction you are traveling, up or down instead of forward, using the accelerometer in your smartphone. Researchers presented the UnLoc system at the 10th International Conference on Mobile Systems, Applications, and Services (MobiSys 2012) on June 27th in Low Wood Bay, England. The researchers, led by Romit Roy Choudhury, associate professor of computer engineering at Duke, imagine buildings containing special wi-fi access points just for smartphones, providing a set of indoor landmarks. This information could be contained on the smartphones themselves, or stored in a database that maps the indoor space more specifically.
UnLoc is demonstrated by a Duke undergrad student, Alex Mariakakis, in a http://youtu.be/VhkXC6TnWzk YouTube video. In the video, he wanders around one of the buildings on campus using his Samsung Nexus S Android phone. As he moves within the building, a dot marks his location on the map stored in the UnLoc app. Researchers claim that although the floor plan was preinstalled in this test, UnLoc can track location anywhere with an accuracy of within 1.7 meters, and usually locates about 10-20 landmarks per floor in buildings they tested the app in that were not stored on the phone.
It is said this technology will be most useful in health care settings. Sonitor Technologies of Norway currently offers an ultrasound-based IPS (indoor positioning system.) Patients wear wristbands that emit ultrasonic signal while microphones throughout the facility pick up this high-frequency. Walls and doors tend to confine signals to a room, so Sonitor’s IPS doesn’t become confused with other types of signals that might be bouncing around in the air. Researchers’ ideas of utilizing multiple types of signals takes this IPS to the next level, making it even easier to find your way around indoors.