Following on from my earlier post about the Garmin GPS accuracy issues that have occurred since the 1st of January 2021, I thought it might be useful to provide a more concise post about the problem.
A large number of users are reporting GPS problems with many of the latest Garmin watches, this issue may even affect other brands, with at least one forum thread about he Suunto 9 Baro suffering from issues.
Devices experiencing the GPS accuracy issue
The problem so far has been confirmed to affect:
- Garmin Fenix 6 series
- Garmin Forerunner 945
- Forerunner 245 and Forerunner 245 Music
- Vivoactive 5
It looked like it was all the newer Garmin watching suffering from the problem, however, users are reporting that the Garmin Forerunner 745 is not experiencing this issue.
Explanation of the GPS Issues: Expired CPE causing GPS misalignment
Garmin themselves have provided no response, so instead we are reliant on the community to work out the issue themselves.
I can’t find the original user comment, but an eagle-eyed user pointed out that their watch was reporting an expired CPE.
According to Garmin:
There are files used by the watch to predict where the GPS satellites are located in the sky at any given moment. Current EPO or CPE files will allow the device to acquire a signal faster when you are going to record an outdoor activity such as a run or ride. Expired files will result in a much slower time frame before the device determines its current location.
For most users, the GPS isn’t completely inaccurate, but instead, the track is misaligned. This is mostly what happened to me, rather than running down the promenade in my town, I ran through the sea.
In my case, the elevation was completely messed up, and it through all my mile times out.
The CPE only helps the GPS, so on a clear day with a strong satellite lock, there shouldn’t be too much of an issue. Yesterday was very overcast (for me), so the signal was not strong.
This perhaps also explains why my times were messed up, it would occasionally jump to the correct location on my route.
It is possible that it is not so much Garmin that is at fault here but the Sony GNSS chipset used on many devices (which would explain Suunto having issues too)
How to check the CPE status of a Garmin watch?
It is quite easy to confirm this yourself
- Go into the menu
- Scroll to the system (it’s quite to press up not down as it is the last item on the list)
- Scroll to about (again, up not down)
- Scroll down through quite a few bits past the Wi-Fi mac address and you will
How to fix the CPE expired status?
The is not much users can do to fix it themselves, Garmin needs to push the update through.
If you regularly sync your watch with your phone, the update should get pushed through automatically. If not I’d recommend syncing with your computer once a day until the issue is fixed (or keep an eye on the Garmin forums).
The best solution in the meantime is to make sure you have a proper GPS lock before you start your activity.
Garmin forum posts referencing the problems
These may help provide live updates on the problems
- GPS accuracy – Fenix 6 forum
- GPS accuracy on Jan 01 2021? – Forerunner 945 forum
- Vivoactive 4 GPS accuracy
- GPS Recorded Track Shifted by FAR with Respect to the Map – Forerunner 245 forum
- Anyone else having GPS trouble? – Reddit