In an attempt to start the year as I mean to go on, on New Years Day I ran a half marathon. While I wasn’t hungover, all the Christmas drinking and eating made it feel particularly gruelling, made worse by the bitter wind.
I had plotted a course and set the watch to use it, with the aim to make the most of the northern wind down our promenade then the backstreets to avoid it a little.
However, from the get-go, my Garmin Fenix 6 Pro struggled to lock onto the course, it seemed to be a couple of streets off. It was overcast, so I just assumed it was taking a while to acquire the GPS satellites.
The continued, intermittently telling me I was on course. However, my lap times were wildly inconsistent, I knew I wasn’t running fast, but my 3rd mile was 9 minutes 14 seconds which is slower than my run/walk speed. Then mile 6 was 7m 25 seconds which is fast for a training run for me.
Paranoid that the times and distance was wrong I ran to 13.5 miles just to be sure.
Massive GPS and elevation Inaccuracies
When my activity uploaded, my suspicions were confirmed, and the plotted course was one of the most inaccurate I have ever seen on any device with built-in GPS.
Running down the promenade next to the sea had me running in the sea for large sections of the run, according to Garmin. The start position was four streets away or 0.3 miles, according to Google Maps. Then to make matters even worse, the elevation data was completely out with Garmin reporting 420ft of climbing across 2 miles on an almost perfectly flat part of my run.
After posting about it furiously on Strava and Twitter, another friend also commented their run was out.
Downloading the GPX file and adding it to a route gave me 13.7 miles, not the 13.5 miles recorded. However, after plotting it properly, it looks like it was closer to 13.1 miles, and it looks like I make have fallen short of the half distance slightly.
Many Reddit & Garmin Forum users having GPS trouble across devices
A quick look on the Garmin Forums also confirms many users experiencing issues.
The issue seems to be extensive and globally with users reporting both GPS and elevation problems
Furthermore people are confirming different GPS modes have the same issues. I was running the defaults GPS + GLONASS but others have confirmed it is occurring on GPS + Galileo
Devices confirmed to have GPS accuracy problems (by users)
This also appears to cover a wide range of devices. So far I have seen:
- Garmin Fenix 6 Pro (me) and other Fenix 6 series watches
- Garmin Forerunner 945 (a forum thread dedicated to it)
- Garmin Forerunner 245M & 245
- Forerunner 45 (multiple forum posts)
- Vivoactive 4
- Forerunner 645/645 M
Possible Causes of the GPS problem
One user cited that there are solar flares over the next few months. It is possible that this could have caused the issue but seems unlikely.
The reported problems appear to be affecting the newer Garmin watches So the Fenix 6, then the new models with the 4 in the product name. So, I am leaning towards it being a firmware issue.
Possible fix for the GPS inaccuracy issue
With so many users reporting a problem, this looks like it will need a firmware fix, however at least one person has stated that rebooting their watch fixed the issue
Another has stated that switching to GPS + Galileo fixed their issue, but this seems unlikely to be a proper fix as others have the issue using Galileo.