iOS12 GPS Accuracy is off?

Hi tntoofore,

In other threads on these forums some people with older iPhone models resolved their problems by replacing their Wifi/GPS chip-sets and antennas. To confirm your problem is not a hardware-related, I would consider the following (it is a re-paste of my suggestions to others above)

Are you sure you had a genuine A-GPS-based location, rather than a cellular/wifi-only based one?

When I had problems with iOS11, my first step was to use GPS Diagnostic. It is an app that is useful because it shows clearly when your phone has a genuine Assisted-GPS based location, or just one based on Cellular triangulation and Wifi signals. During my jog, I would keep checking GPS Diagnostic to see if it was the app (Motion X in my case) to blame, or if the culprit was the A-GPS system itself.

My solution was the following: (do so at your own risk as some sites advise against SIM replacement while phone is on, ***see note at bottom)

remove the SIM while phone was left on

shut down phone (with SIM left out)

turn on phone (with SIM still out)

insert SIM once phone comes back on

This does not work for some, but it made a big improvement for me, and it worked for others in other GPS threads on this forum. I suspect there was an issue with how the phone registers with cell towers (i.e. the cellular aspect of Assisted-GPS), and resetting via this procedure may have fixed it.

Turning the compass setting to True North, which some recommend, may also have helped.

Just for good measure, I turn location settings off for as many apps as possible, I have none set to "Always" and shut down as many apps, especially other GPS apps, when using a particular GPS app. Also, I always stand stationary until I am sure I have an A-GPS-based location, before starting my jog.

***Out of an abundance of caution, I would advise anyone to do the SIM procedure at their own risk, as some sources say you should shut down first. Apple's instructions as of today still do not mention turning the phone off here as far as I can see, although that may be their omission/sloppiness:

https://support.apple.com/en-us/HT201337

https://help.apple.com/iphone/11/#/iph3f11fba92

And another discussion's thread as of today seems to say there shouldn't be a major problem. Check it yourself.

https://discussions.apple.com/thread/7468878

I stand by my comment about reception conditions, blocking, and interference. If you can demonstrate the problem in an open environment with a clear view of the sky (at least 60-70% of the 180 degrees sphere above you is visible and unobstructed) then you may have a problem in the device, and my advice would be Contact Apple Support and get the hardware checked.

Please also remember iPhone doesn't do "pure" GPS, and satellites move across the sky. It does Assisted GPS, which can also derive some fixes by less accurate methods such as cell tower triangulation when necessary. If the satellites have poor visibility at some moment your fix may be determined by land based methods giving significant loss of accuracy. 30 minutes later all the satellites have moved, and from the same location there might be perfect visibility of enough satellites to calculate a fix within a few metres.

Austin,

I thought Google services, including Google Maps are banned in China, aren't they?

Google said on Tuesday it has made “no changes” to its mapping platform in China, denying an earlier media report that claimed it was re-launching the function in China, where many of its services are blocked.

https://www.reuters.com/article/us-google-china-maps/google-to-relaunch-map-serv ice-in-china-nikkei-idUSKBN1F42GD

"Neither Google Mail nor Google Maps work in China, so although you can download your maps before coming to the country, there’s no guarantee that your Google Maps will be current or even show the right directions, so be careful."

https://www.thechinaguide.com/preparation/maps-and-navigation

"The block is indiscriminate as all Google services in all countries, encrypted or not, are now blocked in China. This blockage includes Google search, images, Gmail and almost all other products

https://en.wikipedia.org/wiki/Google_China

That might explain why all your other GPS apps worked except Google Maps when in China.

As for the issues in other locations:

Are you sure you had a genuine A-GPS-based location, rather than a cellular/wifi-only based one?

When I had problems with iOS11, my first step was to use GPS Diagnostic. It is an app that is useful because it shows clearly when your phone has a genuine Assisted-GPS based location, or just one based on Cellular triangulation and Wifi signals. During my jog, I would keep checking GPS Diagnostic to see if it was the app (Motion X in my case) to blame, or if the culprit was the A-GPS system itself.

My solution was the following: (do so at your own risk as some sites advise against SIM replacement while phone is on)

remove the SIM while phone was left on

shut down phone (with SIM left out)

turn on phone (with SIM still out)

insert SIM once phone comes back on

This does not work for some, but it made a big improvement for me, and it worked for others in other GPS threads on this forum. I suspect there was an issue with how the phone registers with cell towers (i.e. the cellular aspect of Assisted-GPS), and resetting via this procedure may have fixed it.

Turning the compass setting to True North, which some recommend, may also have helped.

Just for good measure, I turn location settings off for as many apps as possible, I have none set to "Always" and shut down as many apps, especially other GPS apps, when using a particular GPS app. Also, I always stand stationary until I am sure I have an A-GPS-based location, before starting my jog.

It is pitiful. And to add salt into the wound, people on these forums, including myself get our posts removed on specious grounds.

My advice to most people is to attempt the standard remedies i.e. network reset, restart, set compass to True North, toggle LTE on off, turn off all other apps, turn off GPS permissions for all unnecessary apps, stand stationary and give the phone extra time to get the first location fix, use only one GPS app at a time, use GPS Diagnostic to tell difference between GPS-based location and Wifi/Cellular-only based location. And then do the following:

1) try the SIM trick, which worked for me, possibly by forcing my phone to re-register with cell towers (do this at your own risk; see earlier posts by me and others on this)

2) if that fails do a complete factory reset, test the native Maps app before adding anything else, and if that works set up all your apps and settings etc on the phone from scratch

3) if that fails, get the phone repaired or replaced

4) if that fails buy an Android

Make sure that WiFi and Bluetooth are turned on.

AustinBike wrote:

Something is not right with iOS 12 and the GPS; it ran fine with iOS 10 and 11 on this phone.

Totally agree - I have had a support case open for a week (having given engineers lots of diagnostics - from an iPhone X) and can see multiple mentions on Twitter.

My example: I run the same 10km route 3-4 times a week. The run is tracked by GPS. Every run for two years tracked accurately until iOS 12. The first map below is iOS 11, the second map is iOS 12, a week apart, running the same route. I am now apparently running random routes through buildings. This is not a limitation of GPS, this is iOS 12 software.

tntoofore

75% for 4 satellites on GPS Diagnostic is a good reading.

If possible, you should keep Wifi on, as it helps, like cellular, to improve the accuracy of your GPS-based location.

I think Bluetooth would more likely be the culprit when inside a car. (there are reports of it not working in iOS12 https://appletoolbox.com/2018/09/bluetooth-problems-with-ios-12-how-to-fix/ ). I don't use my iPhone for car navigation and prefer to keep Bluetooth off as it doesn't affect GPS accuracy when walking/jogging. Also turning Bluetooth off via Control Center only disconnects you from Bluetooth networks temporarily rather than turning off the Bluetooth receiver completely, How to really turn off Bluetooth and Wi-Fi in iOS 11 - CNET

pandahill

Thanks I will check it out. I think the reporting feature is mainly for faults with Apple Maps such as wrongly named or non-existing buildings. I have sent feedback via that before (and seen no corrections yet!). Any way of letting Apple know about its sub-par GPS functions is worthwhile. I have also sent feedback via this Feedback - iPhone - Apple

You're in Hong Kong, land of the high rise and urban canyons. You can expect poor or unpredictable GPS performance in some city environments caused by restricted view of the satellites so reduced accuracy or no fix, and multipath errors when buildings reflect the signals, causing incorrect position fixing.

Hi Rob,

I got a replacement for my iPhone X and set it up as a fresh phone - a major hassle. That fixed the problem for a while but the issue came back. It might help, but before you do that, why not try the SIM procedure mentioned above? It doesn't take long and it worked for me and some others on these forums. It might be worth a try just to rule that out. Out of an abundance of caution, I would advise anyone to do it at their own risk though, as some sources say you should shut down first.

Apple's instructions as of today still do not mention turning the phone off here as far as I can see, although that may be their omission/sloppiness:

https://support.apple.com/en-us/HT201337

https://help.apple.com/iphone/11/#/iph3f11fba92

And another discussion's thread as of today seems to say there shouldn't be a major problem. Check it yourself.

https://discussions.apple.com/thread/7468878

My iPhone 7 Plus with iOS 12.01 has same problem. I found if the gps is not working, the update of gps signal is about 6 seconds. When the gps works properly the signal drops to around 1 seconds.

Also sometime if you toggle the location service on/off or turn off wifi would help the update rate.

In your case the problem could have been introduced by upgrading to iOS12 as you say.

Other people on these forums have had problems with GPS after upgrading to iOS11.

I replaced an iPhone X for another one but still had problems, even after installing as a fresh phone - it started okay but the GPS location function eventually started failing after a week or two. This initially led me to believe it was probably due to a flaw in the iOS, assuming I didn't get two dud phones in a row, which is possible.

However, my wife's old iPhone 6S has the same iOS, same carrier, and was tested for GPS in the same locations, and yet always gets first location fix faster than my newer iPhone X, which suggests it could be a hardware problem, or a problem with how the software works with the newer chips.

I also upgraded my iOS using Ethernet and iTunes rather than Wifi to be safe but that didn't help or prevent problems.

If you want to know whether your location is based on GPS + cellular/wifi or just cellular/wifi, you could try GPS Diagnostic, which is my go-to app whenever I want to know what is going on with my phone. It shows you how many satellites you are connected to and gives quality of signal.

I have an iPhone X and use GPS intensive apps (Strava or MapMyRun) to track 10km runs several times a week.

Since the iOS 12 update the GPS has been similarly inaccurate and unstable in every app including Apple Maps.

This has produced nonsensical records of my runs (route going through buildings and 10-15% out on distance).

I am absolutely furious because it is screwing up all my stats and speeds and has been going on for a week now.

I opened a support case last week and was asked to spend nearly an hour creating lots of diagnostics for Apple.

This included a screen recording of GPS in Apple Maps jumping all over the place while I went for a simple walk.

Despite this, I've had no feedback, no resolution, and no ETA - but I now have a £1200 phone that can't do GPS.

Undoubtedly iOS 12 and for this to be happening on a vanilla iPhone X doesn't say much for Apple's test quality.

Austin,

The fact that you could use a HKG-based carrier in China via roaming doesn't necessarily mean you weren't getting your Google services blocked - unless your data bypasses China's censorship systems e.g. by using VPN . Here is another site (dated Sep 2018) that says it is impossible to get Google Maps to work properly in China. "https://welcometochina.com.au/is-it-the-end-for-google-in-china-heres-some-alter natives-1886.html

Judging by this and the previous link I pasted, there may be some functionality but it sounds like the authorities there are deliberately messing with the service.

Whatever the case, you could try the SIM procedure mentioned above (at your own risk - for me, I had to do it while the phone was on, then restart, then re-insert). In my case, the SIM card itself was probably not the problem - it was more likely a problem with how the phone's software calibrated my position using a combination of GPS and celullar/wifi - I think the reinsertion forced the phone to re-register with the cell towers.

Also try setting your Compass app setting to True North.

These steps may not work for you but they don't take long. Worth a try...

Sorry to hear this--I've had somewhat similar problems past 6 weeks or so with OS 11.4.1 on my 6s+. Started in familiar area totally away from tall buildings, etc, with both Apple and Google maps initially placing me about 15-20 miles away from a location I visit often and had always had accurate visualization on both maps. Later, on trip to PA, had difficulty in both Philadelphia and Pittsburgh with both maps--would place us in wrong hotel (each a different one!), difficulty navigating downtown streets while walking, and poor locating for Uber pickups. Very erratic--seemed to work reasonably well during most highway travel. Tried usual resets, etc and visited Apple store where was told could be either software or GPS chip problem. Did a more elaborate reset, but not a full software change. Some better now (?), except recorded distances from usual daily walk erratic. Planned to get the new model still due to come out after first of year and had been delaying OS upgrade to wait for usual fixes, etc, but will certainly wait longer after reading these posts. Clearly, something has happened.