Unintended consequences.
I recently purchased a certain popular phone to replace my flaky blackberry. I have more Gs now. This device has a Assisted GPS functionality. The first time I tried this feature out, it told me I was located somewhere near Dallas North Tollway and Keller Springs in Dallas, Texas.
This phone has never been to that location.
I used to live at that location a number of months ago.
Why does my magic phone know where I used to live before I owned it?
There must be something in common with my current location and my previous location. Hmm. My old apartment, despite being in a gated community, was situated rather close to Knoll Trail Drive, just north of Keller Springs. The location on the map pinpoints me to right about there. What sort of data could Apple be using to locate me when GPS doesn’t work (like now, when I’m indoors?)
In addition to A-GPS, iPhone 3G uses signals from GPS satellites, Wi-Fi hot spots, and cellular towers to get the most accurate location fast. If GPS is available, iPhone displays a blue GPS indicator. But if you’re inside — without a clear line of sight to a GPS satellite — iPhone finds you via Wi-Fi. If you’re not in range of a Wi-Fi hot spot, iPhone finds you using cellular towers.
I’m indoors, so GPS isn’t terribly useful. There’s a gazillion wifi beacons buzzing around me right now, so why would…. OH. Hey. Someone surveyed MY access point, with its old location south of here, as it was located maybe 20 feet from a public roadway. Then, I moved to an area far enough back from a road to not get surveyed, and all of the sudden when GPS fails the only AP providing them with a location cross-reference is the one on my desk, and it “reports” incorrectly.
So, Apple’s superphone relies on data to divine location in certain situations that’s inaccurate and more awesomely exploitable. Sweet. Now I just need a list of AP names or (more likely) MAC addresses, and I could simulate being located in just about anywhere that has been surveyed when I’m indoors.
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