Magnetic field anomalies used to pinpoint your location in a building
By Jan Belezina
July 10, 2012
While GPS tracking tends to be ineffective inside buildings, alternative indoor positioning solutions require the presence of Wi-Fi network access points or other beacons ... or at least, that was the case before a Finnish start-up called IndoorAtlas stepped onto the scene. Its software uses your phone’s built-in compass and measures the anomalies in the Earth’s magnetic field to pinpoint your location in a building with the accuracy ranging from 0.1 meter to 2 meters (3.93 inches to 6.56 feet). If spiny lobsters can do it, so can we, the logic goes.
Lobsters and a host of other animals, such as birds and sea turtles, have a nifty way of figuring out where they are. Not only are they able to detect the direction of the Earth’s magnetic field, but they’re also able to derive directional information from how the field changes due to local anomalies, thus establishing where they are relative to their target location.
Buildings made of concrete and steel also have unique spatial magnetic field signatures. Since the magnetic observations differ depending on how we move through these fields, such magnetic signatures can be used as maps. IndoorAtlas hopes businesses and individuals will use such maps to create indoor positioning applications for mobile gaming, store promotions, improving the efficiency in logistics operations or simply finding their way around a shopping mall.
Here is how it works. As you walk around a shopping center trying to find the loo, your device’s compass takes note of the magnetic field around you. The locally installed app pushes the information in real time to IndoorAtlas’s Location Service, which in turn connects to the map database. The readings from your phone and the map of the mall previously created by taking magnetic field data from the building are used to calculate your estimated position and the estimate is fed back to your smartphone. Now that you see your location on the floor plan, it’s much easier for you to remain calm.
If this does not sound impressive, that's probably because existing technologies already allow for pretty accurate indoor positioning. However, while the magnetic anomaly-based indoor positioning system can work with other technologies to achieve even greater accuracy, the solution is reportedly the first to rely on software only (no hardware installation is required on the part of the site owner). IndoorAtlas offers a complete software package for adding floor plans, populating the map database with local magnetic field data and creating custom applications based on its API (a set of specifications for programmers).
Though I am not particularly keen on technologies that can be potentially used to invade a smartphone user’s privacy even further, I cannot fail to notice the potential here, especially for mobile gaming. Take a look at the video below. Turning a supermarket into a real life pacman arena has never been easier.
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