Thanks for reaching out in Apple Support Communities. I understand that since updating your iPhone to iOS 11 you're experiencing latency with determining your location. I know how important it is to rely on your iPhone for accurate location information; I'd like to help. I'd recommend reviewing the information below about how Location Services works with your iPhone and how to reset this feature:
About privacy and Location Services in iOS 8 and laterHow your iOS device uses Location Services
With your permission, Location Services allows apps and websites (including Maps, Camera, Weather, and other apps) to use information from cellular1, Wi-Fi2, Global Positioning System (GPS)3 networks, and Bluetooth4 to determine your approximate location5.
Apps that can show your location on the screen, including Maps, show your current (approximate) location using a blue marker. If your location can't be determined precisely, you'll see a blue circle around the marker. The size of the circle shows how precisely your location can be determined—the smaller the circle, the greater the precision.
When Location Services is active, a black or white arrow icon appears in the status bar.
Maps, directions, and location-based apps depend on data services. These data services are subject to change and might not be available in all geographic areas, resulting in maps, directions, or location-based information that might be unavailable, inaccurate, or incomplete. Compare the information provided on the device to your surroundings and defer to posted signs to resolve any discrepancies.
Learn more about how Apple and third-party apps use Location Services.
Improve GPS accuracy
GPS accuracy depends on the number of visible GPS satellites. Locating all visible satellites can take several minutes, with accuracy gradually increasing over time. To improve GPS accuracy:
- Make sure that you've set the date, time, and time zone correctly on the device in Settings > General > Date & Time. If possible, use Set Automatically.
- Keep a clear view in several directions. Walls, vehicle roofs, tall buildings, mountains, and other obstructions can block line of sight to GPS satellites. When this happens, your device uses Wi-Fi or cellular networks to determine your position until the GPS satellites are visible again.
Reset or disable Location Services
Location warnings are the requests that apps (such as Camera, Compass, and Maps as well as location-based third-party apps) make to use Location Services with those apps. An app will ask for permission the first time it needs to access Location Services data. Tapping Allow will give that app permission to use Location Services as needed. Tapping Don't Allow will prevent an app from accessing Location Services data. Apps won't use your location until they have asked for your permission and you grant permission.
If you would like to reset all of your location settings to the factory default, go to Settings > General > Reset and tap Reset Location & Privacy. When your location and privacy settings are reset, apps will stop using your location until you grant them permission.
Let me know if what you find after you've reset Location Services.
Best Regards.

