BRAIN SURGERY FROM SPACE? My iPhone 5s is accurate within 5
   meters. *Far too wide to get in the top of my head. Now, GPS is
   run by the US Government, and they're nice enough to lend the
   24-48 *satellites for the use of the entire Planet, including
   enemies of the USA. I have a lot of respect for that decision.
   According to them, 3.5 meter horizontal accuracy is the best we
   can currently expect. Now, if GPS is combined with local Wifi
   signals and Cell Phone tower data, it can probably locate the
   inside of the top of my head. But anything more detailed like
   that (like remote brain surgery), I don't think we're
   quite*there yet. *Close, but not quite there.
   [1]http://www.gps.gov/systems/gps/performance/accuracy/

References

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   1. http://www.gps.gov/systems/gps/performance/accuracy/