gps-details

Apple Watches

Session Summaries

This page looks at a number of wingfoiling and kiteboarding sessions recorded on a selection of Apple Watches.

It looks at the difference between software-calculated speeds (simply using latitudes and longitudes), versus speeds calculated by the GNSS chipsets (almost certainly using the Doppler observables).

A brief insight into speed accuracy estimates is also provided, but detailed investigations and insights are yet to be documented.

It should be noted that different generations of Apple watch use different GNSS chipsets. This can result in notable differences in behavior, especially in relation to the so called “accuracy estimates”, how they are calculated, and how they may be interpreted.

Notes:

• The charts are very basic in nature (e.g. simple legends and lack of axis labels), saving time during production.
• The units for speed are m/s, but you can double the values to approximate the speed in knots.
• The data was recorded without any filters applied, thus showing the true nature of the raw GNSS data.
• Whilst standard speed sailing filters can remove some spikes in the software-calculated speeds, they are not 100% effective.
• Doppler-derived speeds are far more robust than software-calculated speeds that rely on longitudes and latitudes.

Sessions

Some brief notes for a number of sessions, including some graphs which illustrate some key points:

• Apple Watch Ultra
  • Apple Watch Ultra #1 recorded whilst Wingfoiling.
  • Apple Watch Ultra #2 recorded whilst Wingfoiling - highlights the utility of speed accuracy estimates.
  • Apple Watch Ultra #3 recorded whilst Kitesurfing - highlights the utility of speed accuracy estimates.
  • Apple Watch Ultra #4 recorded whilst Wingfoiling - highlights the utility of speed accuracy estimates.
• Apple Watch SE 40 mm Cellular
  • Apple Watch SE 40 mm Cellular #1 recorded whilst Kiteboarding (or maybe Wingfoiling).
• Apple Watch SE 44 mm
  • Apple Watch SE 44 mm #1 recorded whilst Kiteboarding.
• Apple Series 8 45 mm Cellular
  • Apple Series 8 45 mm Cellular #1 recorded whilst Kiteboarding - general issues are possibly evident?
  • Apple Series 8 45 mm Cellular #2 recorded whilst Kiteboarding - general issues are possibly evident?
• Apple Watches Series 5
  • Apple Watches Series 5 #1 recorded whilst Wingfoiling - highlights the utility of speed accuracy estimates.
  • Apple Watches Series 5 #2 recorded whilst Wingfoiling - highlights the complexity of speed accuracy estimates.

TBC

A further investigation might wish to look into whether the cellular models of Apple Watches suffer from RF interference?