app gathers data from your phone's various sensors

Once in a while, you might feel like you're being watched. Lately, I know I am, thanks to a smart-phone app that stealthily tracks my every move, no check-ins required, with greater accuracy than common geolocation tools. Called Placeme, the free app takes advantage of the smart phone's sensors and its GPS and Wi-Fi capabilities to figure out where I go and for how long, and stores this data in a private log on my iPhone. It may sound creepy or unnecessary, but as more people carry smart phones with them everywhere, demand for this kind of persistent location tracking may grow—not just from marketers, but also from individuals who want to keep an eye on their own movements or of loved ones with medical conditions such as Alzheimer's. At least, that's the hope of the startup behind Placeme, Alohar Mobile, which has also released a software development kit to help coders create apps that can log your movements accurately and efficiently—without running down the battery in your smart phone. To use Placeme, available for the iPhone and phones running Google's Android software, you must keep both your GPS and Wi-Fi on. As you travel around, the app will silently log the places you visit. Within the app, you can view day-by-day maps of where you've been. Each destination you spent time at is marked by little pins; tap on a pin to see how long you were there and check out a Google Street View image of the location. You can also add notes about a location (a favorite dish at a restaurant, perhaps). There's also a searchable, alphabetical log of all your destinations.

The app gathers data from your phone's various sensors and GPS and Wi-Fi, encrypts that data, sends it over a secure connection to Alohar's servers, and then calculates your location. To cut down on battery drain, locations are calculated remotely, and the app only takes GPS data samples at certain times (like when the accelerometer is active). Alohar Mobile cofounders Alvin Lau and Sam Liang imagine a future in which apps can draw useful information from all this location data: for instance, automatically alerting emergency services if you're injured in a car crash and letting paramedics know precisely where you are. An app for Alzheimer's patients and their families could show where that person has gone in the last 24 hours. Lau and Liang have demonstrated these types of apps at recent conferences, and they're hoping developers will come up with many more applications, ranging from health and fitness to shopping, using their platform. More than 250 developers have so far signed up to use their free software development kit since it was released several weeks ago. Key to Alohar's platform is making location detection more precise than it normally is. Liang, formerly a platform architect for Google's location server platform, says that using GPS, Wi-Fi, and cell tower triangulation, as many apps and services including Google Maps do, can result in a wide margin of error—illustrated in Google Maps by the transparent blue ring that pulses around the blue dot marking your current location to indicate a degree of uncertainty.

Alohar says that location detection that incorporates data from the other sensors on a smart phone, such as the accelerometer and compass, can calculate your location more exactly. Though they haven't yet made this feature available to developers, Lau says, Alohar's platform can also determine if you're walking or driving. David Petersen, CEO of Sense Networks Sense Networks, Inc. 1123 Broadway (between 25th and 26th Street) Suite 817 New York, NY 10010, a company that mines location data for useful information about an area, thinks there's plenty of room for improvement in location data gathering. While GPS can accurately show where you are, it sucks up so much battery life that your phone is often not using it to pinpoint you, he says, and other methods are less reliable. He notes that greater accuracy could also mean better targeted ads. "I think these guys are working on a very valuable piece of the puzzle," he says. Alohar has a ways to go, though. In dense urban areas, it seemed to have trouble determining exactly where I was, and it didn't mark every place I went. Fortunately, it can be trained. Once I taught it that I live down the street from a Pilates studio and not inside it, the app was able to correctly mark me as home whenever I was actually there. Which, according to Placeme, is more often than I'd like to admit.

Source: Massachusetts Institute of Technology