watchOS 10 update has ruined GPS on Ultra during open water swimming.

Hi,

I'm the developer of Open Water Swim, and I have had multiple reports and have also confirmed with my own testing that the WatchOS 10 update has seriously degraded GPS data during open water swimming, both with the native Workout app and with Open Water Swim. The data provided by CoreLocation is no longer accurate or trustworthy. I will post several pictures showing before and after update swims:

Here's the raw data (mapped) of a swim done with watchOS 9 on the Ultra.

Same swim today:

From another pair of users: These two went TOGETHER, one with watchOS 9 and one with watchOS 10. You can probably guess which is which.

Watch OS 9 swim:

SAME SWIM WITH A PARTNER ON WATCHOS 10 (beta here)

And another, again, two people swimming together, one watchOS 9 and one watchOS 10.

watchOS 9

Same swim, same time, watchOS 10

I have filed two feedback assistant reports with APPLE. One when it was still a beta issue: FB12587468. This one has zero response from apple.

And now a second one filed with watchOS 10 release: FB13192409

Apple devs, I know you're here and listening, so please let's get this fixed ASAP. Thanks

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I have only seen two outdoor swim workouts with watchOS 10, but the GPS trace for both of them was awful. Much worse than I have seen in the past.

It's a very small sample and probably too early to be sure, but I am probably seeing the same GPS issues as you when swimming outdoors with watchOS 10.

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cfc
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I am including three example data points that show there is an issue. These are locations that are mathematically impossible because the accuracies provided by the CoreLocation are less than the distances apart. These are CSV files each with two locations separated by a distance greater than the sum of provided accuracies. Typically one second apart (we allow 1 meter per second error)

text-FC597A06C33E-1.txt

text-4EAA0C645F55-1.txt

text-F8A0F1CB22DE-1.txt
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visskiss
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