Occasionally, the location of a user will suddenly shift by several hundred kilometers to different airports, even though the kCLLocationAccuracyBest level of location accuracy is being used, and most of the time, the location accuracy is less than 50.
Occasionally, the location of a user will suddenly shift by several hundred kilometers to different airports, even though the kCLLocationAccuracyBest level of location accuracy is being used, and most of the time, the location accuracy is less than 50.
Generally speaking, there are two factor that lead to this kind of large jump:
The user placed their device in a location that isolated it from GPS and/or manually disabled GPS by putting the device in airplane mode.
(optionally) Wi-Fi location data was available that made the device believe it was "stationary" when it was in fact moving.
As a concrete example from a completely different scenario, several years ago I worked with a developer who'd managed to driver ~4 hours "without moving". After talking exactly what happened in detail, we eventually realized that:
His phone had been in a backpack which had been placed behind that passenger seat with other luggage piled on top. He also had very poor cellular reception in that area, ruling out cell location.
He had a WiFi spot that he'd setup a few weeks earlier but which had been left at this home until this particular trip.
That "stationary" Wi-Fi location the provide the on location data until his drive ended and he give his phone clear signal again.
__
Kevin Elliott
DTS Engineer, CoreOS/Hardware