Wednesday, February 07, 2018

Notes on Samsung Galaxy S7 and S8 Location Inaccurate / GPS Problems

What I've learned about Samsung Galaxy S7 and S8 location problems after a month of troubleshooting and research:

- Problems include jumping to a completely different location from a previously accurate fix, indicating movement when you are still, or general inaccuracy up to a mile from your actual location.
- Seems tied to Nougat, specifically 7.0. General reports indicate much improved location accuracy pre-Nougat with S7 (S8 shipped with Nougat). Other reports indicate increased accuracy with 7.1 on other devices (Samsung never released 7.1 for the S7 or S8). Hopefully the forthcoming Oreo update will help resolve issues. [EDIT 9/28/18: Upgrade to Oreo didn't make the GPS issue better at all.]
- Battery optimization for Location Services MUST be turned off to avoid complete unreliability. (Samsung turning on Battery optimization for Location Services by default makes no sense whatsoever; on Google's own phones you aren't even allowed to do this. The only item you aren't allowed to optimize is Play Services... which plays a big role in serving up ads in apps. Go figure that Google enforces that restriction but lets Samsung screw up Location Services.)
- In addition, I recommend disabling Battery optimization AND App Power Monitor for Google Maps and any other location-aware app that is important to you.
- Including Wi-Fi in location detection makes a huge positive difference, but only when Wi-Fi is on. Wi-Fi scanning when Wi-Fi is off is not nearly as effective. Avoid turning Wi-Fi off.
- Using an app like GPS Status Toolbox to reset A-GPS data and calibrate sensors and compass helps noticably, but the effect of these actions is lost when the phone is rebooted and must be repeated. Avoid rebooting the phone if location is working halfway decently. You may find it beneficial to repeat the reset/calibration actions every so often. [EDIT 9/28/18: I have had to do all these things weekly to get any chance of decent accuracy.]
- In general, the default location settings (High Accuracy with Wi-Fi and Bluetooth scanning on in the Improve Accuracy options) are best. Changing them does not provide any benefit.
- Some reports suggest that certain cases, especially those made of metal, can affect the GPS antenna at the top of the phone. It is worth comparing location performance with and without your case. Consider a soft silicone case instead if your case proves to be an issue.
- If you have your phone carrier's app on your Galaxy S7 or S8, ensure that Network Diagnostics is turned off, or uninstall or disable the app entirely. Some reports indicate that this interferes with location operation.
- Replacing the SIM card is an oft-suggested potential fix, but I haven't been able to find an instance of where it solved anyone's problem.