Poor GPS accuracy on iOS 11 / iPhone X

Can you put numbers to the accuracy involved?

I'm the main dev' of a mapping application, using location service since 2009.

I did'nt notice that fact (poor GPS on iPhone X) until customers started to report it. I have an X but did not pay attention to GPS accuracy on it at first because I was so used to a good result.

I can see for sure that tracks (walking or riding, bike or horse, all tests in open field) are much less precise with my X than with my 7+. Also the altitude is very unreliable despite the verticalAccuracy value pretending to be 3m ! So are customers reports.

Speculation on users forum are on internal chip or sofware driver modified for Galileo and recessing in the process. Hardware issue is likely since not all devices seem affected. Not found any Apple statement on this beside report from customers "this is a known issue".

Also, the "GPS Diagnostic: Satellite Test" application on AppStore, show worst reception on the X.

BTW, I wonder how this application and some others can gather satellites information, without using some sort of private API and still being approved. I'd love to be able to collect more information on GPS reception into my own app…

We are seeing similar problems for our iOS 11 users of iPhone X and 8.

We have a Waze-like app that heavily relies on CLLocationManager and we are seeing strange CLLocations getting returned. Some have a correct speed and accuracy (under 10m), but without a course (-1). Also some of the logs we see have heavily switching accuracy, from 5m to 300m and back in a couple of location updates every second.

This seems to occur more frequently in users of iPhone X and iPhone 8, however, we are also seeing reports of users that don't have those devices and also get invalid course. We are going to make a workaround to this problem to calculate the course ourselves when course is invalid.

I've also found this article that maybe shows this problem occurring for users of iPhone X and 8: http://appleinsider.com/articles/17/11/09/some-iphone-8-iphone-x-users-suffering-from-gps-issues-software-fix-appears-to-be-coming-in-ios-112

Though that should mean Apple fixed it in an iOS update, which doesn't seem to be the case for our users.

Not sure if this ever got fixed in any subsequent iOS update, but apparently a reboot with the sim ejected helps.

Had a 6s with very poor positioning and long waits for GPS lock, which was jumpy even then, with the above method fixing the issue (for now).

Could potentially suggest this as a workaround for those of your users experiencing issues

Before I did the trick ”rebooting with sim ejected” I would get between 30 - 200m accuracy.

After reboot with sim still ejected the gps immediately jumped to 5m accuracy. :-)

inserting back the sim, and accuracy still at 5m.

smells like the assisted gps using cell location information has a negative impact on the gps accuracy.

I read one story on internet of people complaning that there mobile provider needed to do an update of the phone sim settInga to get a-gps working, Mayby the a-gps data is corrupted and conflicting with satelite data, resulting in jumping accuracy?

Iphone 6s, iOS 11.4

My understanding is that A-GPS only improves the startup performance of a GPS receiver: it doesn't improved the subsequient accuracy of the position reports.

There is often a confusion between A-GPS, which improves startup performance, and D-GPS, a much more sophistaced system, which improves the location accuracy of the GPS from metres to centimetres.

Unfortunately it did not work in my case. I have tried any fix options I found in the internet. Amazing how many people have been frustrated by GPS accuracy issues since iOS11. Unbelievable that Apple was not able to fix it. Users of my app are reporting similar issues with iPhoneX and iOS12.2 now. I was able to reconstruct it on my development iPhones. Until now I have not found a way to resolve it for my customers. The only option I have for the moment is to take the app out of sales... So, would be grateful if someone could help with an advice.

I just upgraded from iPhone 8 to iPhone 11 Pro - and the GPS accuracy has decreased so much. I brought my phone in for repair because of how bad the GPS was and they gave me a new one, but the new one is pretty bad as well. When I'm outside, my position on the map is constantly bouncing around a circle of about 250ft diameter.

What does your app do, exactly and what type precision are you after for it?