Just a really quick post to give some context on an issue some people (but not all) see where your recorded GPS track is balanced by up to a hundred meters or more. In general, the pattern of your path is correct, but it may be laid down to one side or the other. However, in many cases by completing the task, it resolves. In other words, it is largely a one-time affair.
The issue seems to be largely affected by companies that are accelerating the GPS chipset in their devices, which is basically every new Garmin device in the last few years, which most new Suunto machines in the last few years, all Polar machines in the last few years, all COROS machines, the Wahoo RIVAL, and more. More or less everyone but Apple.
A pretty rough list of affected tools (I miss a ton here, these are just the most popular ones)
– COROS everything but the original COROS Pace
– Garmin Forerunner 45/245/945 / Fenix 5 Plus / Fenix 6 / MARQ / Vivoactive 3/4 / Venu
– Garmin Edge 130/130 Plus 530/830/1030 Plus
– Polar Vantage V / M / V2, Grit X.
– Suunto 5 & Suunto 9
– Wahoo RIVAL
Again, I miss the burden of a boat here, but those are the big tickets off the top of my head.
All of these companies have moved to a GPS chipset since around 2018, with Polar and Suunto jumping on board first, followed quickly by Garmin, COROS, and more. The GPS chipset is widely used by these companies because of the power savings that deliver longer battery life.
But – that is all over the point, and not the cause. The issue is related to the ephemeris data file, also known as the EPO (Extended Prediction Orbit) or Ephemeris Predictive Connected (CPE) file. Or just the satellite pre-cache file. This is the file that will be delivered to your device on a regular basis (usually every few days). This file is what makes your watch locate GPS satellites almost instantly when you go outdoors. It is basically a deceptive page of where the satellites are for the next few days, or up to a week or so.
Your watch or bike computer receives this file automatically via Bluetooth Smart from your phone, WiFi, or USB, depending on how you connect your watch. Most companies deliver it whenever your watch is in sync and needs a new version. So from your point of view, you never do anything – it just happens quietly at the back.
Currently, the data in this file is incorrect, so the data that your watch uses for those first few minutes is also incorrect – leading to the shutdown. You can see an example of this below, from one DCR reader:
As the watch maintains its connection to GPS satellites over the course of the operation, it usually corrects itself how it pulls in updated data from above. Most report that solve itself either before the end of the assignment, or the next assignment. You can see that here from another DCR reader:
The only thing here – similar starting point errors on my Fenix 6X Pro and my wife’s Forerunner 45S, then they fix them myself – I walked, she ran, so my route is more accurate because he had more time to solve I believe… pic.twitter.com/tZ4ysgYPtW
– ac72 (@ ac72) January 2, 2021
To help solve this, you can simply stick your watch / bike computer outside and allow it to record one hour activity, then delete it afterwards. He will have received the necessary satellite information for his own correction.
But it won’t affect everyone. For example, I tried today with two Sony – based watches (Garmin FR745 and FR945) to force it to go down a wrong path – and it wouldn’t. I suspect this is because in my case the watch was beaten a few times while playing with my kids yesterday and today, so it is my opinion that he had reloaded what he needed to get right out of the gate. I also tried two non-Sony chipsets (Fenix 5S and Apple Watch SE), and saw no more problems.
Speaking to Garmin today, they are working on a solution for the issue, believe that they will most likely just update the satellite pre-cached data from the server, and that watch will get a grip just as it always will. But first they (and others) work to find out exactly what is wrong with the data that is causing this.
Speaking to another person in the industry who was dealing with the issue, they noted that 2020 was technically 53 weeks, and this is the 53rd week. Therefore, the subject of Sony ‘s suspect data file may be related to that complexity.
See… just when you thought you had fled 2020, it is still there waiting for you at the beginning of your run.
With that – thanks for reading!