GPS Strava Issue

[srose79496]

In the last week, starting 3/10/2025, my Samsung S21 has experience GPS bounce during my runs while logging via Strava.  This has been pretty regular throughout my run resulting in an approx 30 sec per mile pace discrepancy.

My phone updates are current.  I've tried adjusting all the settings I could find but struggling to understand what changed in the last week.  I also tried on another Samsung S21 (my wife's) and ran into the same issue.

Prior to last week, my GPS logging was accurate within a few sec per mile.

[smiley · Accepted solution]

Have you tried using a GPS toolbox app from play store to see how the navigation satellites look ? I use 'GPS STATUS' app. others are also available.

From here you can also manage the Assisted GPS state... force a cold start to remove all GPS data from the phone memory, and also download assistance from the network.

This assistance should happen automatically but sometimes with GPS and GNSS... strange things happen.

The other thing is perhaps your permissions to mapping applications such as strava have changed... so check that access is allowed to strava / Google maps etc. If there is not the permissions / assistance then it can degrade the performance.

However once a GPS receiver has more than 4 satellites it should be able to make a position fix and hold this ok. But tree covered paths and high rise buildings in urban environments can worsen the quality of positioning.

Just to caveat all this... I am a GNSS engineer in my day job, so I do know a little about this subject.

Let us know if any of this helps.

Smiley

[smiley]

You may also wish to check in the strava app settings that mobile data is allowed when being used.

I don't use strava... this example below being with maps. You may want to ensure the data in the bottom selection is ON by default.

[srose79496]

Thanks for the input on the strava app.  I checked all the strava settings - I don't see anything similar to this.

[srose79496]

Thanks for the detailed post.  I checked all the permissions and they all look fine.  I even factory reset one of the phones to see if I could start from scratch.

All I can figure is a software update from Strava, Samsung/Android but not sure what it would be.  Seems odd that I changed nothing but this started a week ago.

My next steps:

1. reset via GPS toolbox(done) - will update with results after next run.

2.try a different Samsung phone (S23) to see if I have similar results - will use this on my next run as well.

[smiley]

Perhaps if you locate the app icon and long press.

Click the ! Info button.

Scroll down to mobile data.

Scroll down to the bottom. These mobile data options may be available.

I guess this is clutching at straws a little though.

GNSS Navigation should be fairly autonomous once a position fix is made. But not having the data connection could mean it could impair the performance slightly. Moreso in the first fix quality and speed of that initial position.

You could consider uninstalling and reinstalling strava as well.

Your issue does sound very odd and that all worked well beforehand...

Would be interested if you find a resolution to this 👍😉

Smiley

[srose79496]

I located the data setting on Strava - it was already on.  

Today's test - S21 improved after resetting GPS state.  Still has some bounce.  S23 (phone has no SIM/mobile connection) matched expected pace.

In Strava, you can see little squiggles in the map and the data where the GPS has issues.  The pace between the two was similar but my S21 showed about :10 a mile quicker since it had me jumping more.

The only thing I can figure is an Android/Samsung change in the latest update.

For now, I'll use the S23 for running and continue to research the S21.

Thanks again for your suggestions.

[srose79496]

So, after twos days of testing with multiple phones, the GPS readings are reasonable on the S21.  In general, I'd expect this to be less accurate since much older and it is fairly close now to the S21.  I'd say your GPS state reset seems to have fixed whatever issue was going on last week.  Thanks again.