[PragmaticPulp]

> After about a kilometer I have to cross a busy street, I need to pause there regularly. Pausing always fixes erratic mode.

Given that the “erratic mode” only impacts the beginning of the run and disappears suddenly at known locations, this sounds like an issue of delayed GPS lock.

And given that the problem didn’t exist in the past, it could be a software issue due to upgrades. Or it could be a hardware issue that developed over time, such as something impacting GPS receive sensitivity. Or it could even be a new source of RF interference in the GPS range near the author’s start point, which impacts GPS lock until they get far enough away from it.

Interesting issue, but note that this issue appears to be specific to this one specific person, not a general issue with all Apple Watches as some in this thread are speculating. I certainly have not noticed this behavior on my Watch even with the latest updates.

[matsemann]

It's a common issue with how the Apple Watch forces you to start the activity before it attempts acquiring gps lock. For many that may work fine, but also for many that gives erratic behavior in the start where they live. All other brands behave the opposite.

Based on this article they've fixed it for Ultra, at least https://www.dcrainmaker.com/2022/09/apple-watch-ultra-in-dep...

> Assuming you’re ready to go, then you’ve got two choices with Apple Watch Ultra. You could go the ‘normal’ route for all Apple Watches up till now, and wait for the 3-second countdown. Once that countdown completes, it’s at that point that the watch goes off and gets GPS signal and HR acquisition – not before. However, the Ultra edition includes a new ‘Precision Start’ feature, that lets you first open the workout up, then see the signal status before you begin

[gmurphy]

That was my theory too, so I started opening Apple Maps and viewing my location on my watch before starting my run, and anecdotally it increased the initial accuracy by a great amount

[icehawk]

Sadly, the guy didn't publish the tools they used to produce this. I would have been interested in seeing if I see a similar erratic mode in my own data.

[qwertox]

Couldn't the watch request the list of satellites locked to the phone and pretend to be locked to them as well, instead of building the list by itself?

[mbreese]

That’s possible and I k ow the watch will do this. I run with both my phone and Apple Watch. For long runs 20-26 miles, I use the phone for music to my AirPods. I run slow enough for the watch battery to be drained after a marathon of I try to have my watch do it all.

I’ve had a few instances where the running track gets all wonky when I go through something like a long underpass tunnel. It’s long enough to miss a GPS signal for many minutes. Instead, it guesses where I am based on distance to cell towers (I think). Or at least, that’s what the running trace seemed like to me. Everytime I went under a tunnel, I found out later that I ran a 3 minute mile — on miles 16, 20, and 22 (that’s not possible).

Now I just disable Bluetooth on my watch entirely while doing long runs. I’ve found the watch by itself to be more accurate, in general.

[gumby]

Plenty of people, including the author and me, don't carry a phone any more, just a watch. Anyway the watch really needs its own fix as the phone will be displaced from the watch and have a different orientation even if you have it close by.

[tinus_hn]

If the phone is available the watch will just ask the phone for its location and not waste its own small battery.

[shp0ngle]

The issue seems definitely related to GPS.