Wi-Fi connectivity has become widespread, particularly in urban areas, to a point where many sites have multiple active networks. When looking for available Wi-Fi connections while out in public, we have all seen the long list of possibilities that often appear on our phones or computers. Some are for private use only, while others are active for the convenience of nomadic users looking for a place to do some work on a laptop or a way to continue using their mobile phone when their carrier’s signal is weak or nonexistent.
Any of those networks appearing on your device are potentially usable, either with the required password or, for unsecured ones, by just choosing to connect. You may not realize that the routers and access points enabling these networks are potentially useful for determining the location of mobile phones and other devices in the area.
Generally described as Wi-Fi Positioning Systems (WPS), their objective is to improve the availability and accuracy of location data for Wi-Fi enabled devices. Although these devices may have GPS capability, a WPS may be able to determine a location in an environment where GPS is deficient (indoors, for example). For some applications, it may be sufficient to rely on WPS only.
The next time you’re walking through the local shopping mall, a WPS may be tracking your mobile phone. In this type of indoor space, there are many Wi-Fi access points for the service to use. In some instances, a WPS will calculate your location using data from the interaction between your phone and the nearby access points. WPS service providers have also been storing data from the communications between mobile devices and access points wherever possible, enabling them to increase accuracy.
How do these WPS providers get the data? Your mobile phone sends it to them. Information like the identifier for your phone (its “MAC address”), the MAC addresses of the access points in range, the strength of the signal, GPS coordinates, etc., are harvested from your phone by a third party who provides it to WPS. As a result, some WPS databases contain billions of records from sites all over the world. The immense amount of data in a WPS database offers a lot of insight on a macro level about mobile phone users’ activities.
So, what are the typical uses for this service? At a high level, anytime a device with Wi-Fi capability needs a location, either because it lacks GPS capability or in a place where GPS is currently unavailable due to environmental factors, the WPS may provide it.
Vendors also incorporate WPS capability into more comprehensive solutions, using more than one technique/technology (GPS, cellular, etc.). By providing a standard API, their service provides a location using the best option, without requiring the calling application to code for technology differences.
With an increasing focus on data privacy, the information a WPS provider harvests may become less readily available. However, in the near term, this type of location service is an essential piece of the never-ending quest for device location – everywhere, all the time.
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