People who use global positioning satellite (GPS) receivers know buildings and other structures can degrade the information, which makes getting an accurate indoor position fix almost impossible. But researchers at Duke University have developed a way to change that.
Romit Roy Choudhury, associate professor of computer engineering at Duke's Pratt School of Engineering, told me that indoor-position information might let shoppers' cellphones tell them about products in front of them or help parents locate their children in malls. Such a capability might help with "navigation" in hospitals or in smart homes. "Imagine lights in your home following you based on your precise location and activity. Our technique takes advantage of 'invisible' indoor landmarks a mobile phone can sense."
He said motion signatures created by elevators or stairwells could serve as landmarks. Once a phone senses such a landmark, the phone could infer its location and then track its path from that point using accelerometers, compasses, and gyroscopes.
I remain skeptical. First, I usually know what I need when I go shopping. I don't have time to browse through aisles of other products, and I won't wait for my phone to describe features of nearby products. As for lights that turn on and off based on my position, I can buy switch replacements that do this without position information. Someone who needs directions in a hospital, for example, can usually find a map or ask someone else for help. And when kids get old enough to cruise through a mall on their own, they'll have cellphones, and parents can simply call and say, "Where are you?"
Electronic accelerometers, compasses, and gyroscopes already can provide good tracking information indoors. (The Duke team reported an average accuracy of only 1.6m.) Instead of relying on GPS data and "invisible" indoor landmarks, sensors in smart devices, combined with RFID tags and Near Field Communication (NFC), could provide accurate position information and a way to calibrate locations quickly. Find a "calibration spot," place your phone next to it, and you get updated coordinates to within a few centimeters -- that is, if you need this information. It might amuse some to know we could navigate quite well indoors and out before the advent of electronics.
As we've discussed before, newer phones already include NFC capabilities for use with an app such as Google Wallet for immediate payment at checkouts. Microsoft Windows 8 software and Windows Phone 8 and Surface hardware will include NFC, too. Microsoft already has application programming interfaces for the PeerFinder and ProximityDevice classes. If you're an app developer, you can jump into NFC and use it as you choose. Indoor navigation might be such an app, but I doubt we really need it.
There's a dark side to indoor navigation, too. You might not know whether your smartphone lets someone else track your position. Beware.
What's your take on indoor GPS? Let us know in the comments section below.