Hello,
while seaching for this problem I already found the following thread here: https://forums.developer.apple.com/message/283572#283572 but then mainly focus on the horizontal accuracy. I haven't made that observation so far (or at least none of our users complained about is yet...) but what we have a lot of problems with is vertical accuracy. We have a hiking app where the user wants to know his ascent as accurate as possible. We use the Barometer for a more reliable result, but still need the GPS to from time to time recalibrate.
Is this a known Hardware-Issue that Apple admits? We only see those Problems in iPhone X and 8. Not all of the devices, but when users complain it's either the one or the other device. We then ask them to send us debugging Information and those look like the following. The red-line is altitude reported by the GPS and the blue one is the far more accurate one.
If there is any known software-tweak we could do, I'd me super happy to know.
Would be cool to hear something from somebody who is familiar with the matter.
Cheers,
Georg
