gpstest VS magisk-supl-replacer

If you really want to see all the gps-like services out there and have android, you must play with the open-source GPStest

https://github.com/barbeau/gpstest

I've been fascinated for years how badly GPS does altitude (mean-sea-level)

in the USA they had to build an augmentation system for airplanes for altitude (WAAS)

Use https://github.com/barbeau/gpstest (Android only). It give the most real time data on GPS and accuracy.

GPSTest (version 3.10.0): An app for testing GPS and GNSS capabilities of a device

I'm the developer of the GPSTest app, and I built a crowd-sourced database of device GPS/GNSS capabilities.

It is possible on quite a few modern Android phones to access raw receiver data and do post-processing using a rinet file to get mm-level accuracy. It's a little over my head since this isn't my industry. One of Google's more obscure Android apps to be used with it: https://play.google.com/store/apps/details?id=com.google.and...

GPSTest also carries some logging functionality to do the same: https://github.com/barbeau/gpstest

If you did not install GApps try outdoor with an unobstructed view of the sky for 10 minutes to get the first fix with apps like GPSTest by barbeau or SatStat for example.

I hope more people can contribute with GPSTest app.

For a visual of what speed accuracy figures one might expect, I suggest trying GPSTest (not to be confused with similarly named apps). It'll display accuracy values along with many other values.

GPSTest by barbeau

If you install this app, you'll see exactly what GPS data your phone is picking up.

https://github.com/barbeau/gpstest

I can see GPS, Galileo, Chinese, Russian, and Japanese ones.

Either of your proposed solutions sound like they would work, although I don't know for sure how to redirect SUPL to another server, as I've never done it, but it looks like this Magisk module may help. I recall that Nokia used to run one such server, and there on the module's GitHub it mentions a Sony Ericsson server, and I think some Chinese-brand phones use Chinese servers. I'm not sure if any of that sounds like a good option to you! I don't think there are very many SUPL servers around.