gps-details
Apple Watch Ultra
Author: Michael George
Created: 16 Nov 2024
Overview
This is a very quick look at a single test of the Apple Watch Ultra, recorded using the Waterspeed app.
The data from the Apple Watch Ultra (red) has been compared against a 5 Hz Motion GPS (blue).
There are similarities in many places but also some big differences.
Here is the Apple and Motion data, should you wish to examine it for yourself.
Obvious Issues
Initial Acceleration
When zooming in to the the latter part of the session, initial periods of acceleration are not being recorded by the Apple watch.
Repeated Speeds
Zooming in further a little further it is also evident that identical speeds are being recorded. 3 seconds worth of 37.543 knots is highlighted.
Expectations
Neither of the issues described above should be evident if a GPS device is faithfully recording speed data. The data below compares the Garmin Forerunner 255 (green) against a 1 Hz Motion (blue) and 5 Hz Motion (red), showing the Garmin doing a great job.
Subtle Issues
In the interests of saving myself some time, subtle differences have not been written up in this short document.
Summary
This is document is a quick illustration of two obvious issues affecting the Apple Watch Ultra.
- Lack of speed data during initial periods of acceleration
- Identical speeds being recorded for multiple seconds, suggesting duty cycling or filtering.
Neither of these issues should be evident if a GPS device is faithfully recording speed data.