ETA calculation still wrong during activity

5767025 6 days ago

There was a previous thread about the ETA calculation being wrong during activities with a course: [BUG][21.19] Time to destination ETA calculation not working

That thread is now locked but I still see the issue.

Today when hiking a ~20km course, I was watching the ETA as I wanted to know which train I would catch at the end of the activity. The ETA appeared reasonable up to around 10-12km, but after that it became obviously wrong, saying I would finish the remaining distance in around five minutes.

I don't often look at the ETA, but I remember this problem in the past. It does not seem to have been fixed.

Does anyone else still see the same problem? My watch is the FR955 (no solar), running latest production software 26.08.

Just to note that the last "reasonable" ETA I saw, maybe 1h45 before the end, turned out to be correct to within 2 minutes. So the algorithm is good up to that point.

0 7419217 6 days ago

Yes I can confirm the bug is there yet on my fr955 26.08

I had no answer, no news, nothing about this issue.

The feature was working before, then they broke it and never repaired.

ETA is erratic and unreliable.

What's worst, is that this is even dangerous from a safety perspective as it's providing a false information. Yes we all need to apply our brain when hiking or running on the mountain, but ... having a tool providing a false information is not helping.

0 Bit 2 days ago

Experience from years ago; when I used ETA during runs with a course it would only work if I had set a "virtual partner" pace during creation of the course. My old Garmin 12XL handheld was much better at calculating ETA than my Fenix. I still always set pace goal in courses just out of habit and ETA is not bad.

ETA calculation in the days before maps relied on crosstrack (how well your heading is aligned to your destination) and speed, resulting in VMG (Velocity Made Good). The Fenix 3 used magnetic heading, not GPS heading for this, and it never worked well in urban areas I would not expect VMG to still be used for calculating ETA on devices that have maps though, but you never know how long old code can live on.