Garmin Instinct GPS watch speed readings?

[LaPerouseBay]

I don't ski, but this is how it works for them. 

Their GPS is also 10Hz.

https://youtu.be/2LsXeMiU6dU?si=uXAe9JFtOXjxoAPK

[LaPerouseBay]

Here's some Gopro11 GPS sensor data in high speed action. 

https://youtu.be/3DRB3ikGUE8?si=MB54sqc5fDvWxaKm

I tested the Garmin Instinct in both GPS modes, GPS+Glonass and GPS + Galileo.
Both dropped a lot of data to zero.  Usually 2 seconds at a time, sometimes 4.     

The Gopro11 sensor also has the ability to integrate a third constellation, the Chinese Beidou.

In my neck of the woods, GPS usually has 6 satellites overhead, Glonass and Galileo 6 each and Beidou 12 to 15.

So, Gopro11 sensor has a better set of signals to choose from.

Higher sample rate can improve location and speed readings. 
Garmin misses a lot of data in my neighborhood.  At 1Hz, that ruins the curves I look for. 
All data smoothing is set to zero in these images.
That's a 40 second timeline.   

[LaPerouseBay]

Here's what Garmin gave us back in the day, with the Forerunner 305, at 1Hz.

Again, zero smoothing chosen in my telemetry program.
May be a tiny bit of smoothing, but that curve is fine for what I do. 

So, it looks like very few signals dropped, compared to Instinct.
I'll turn off Glonass and Galileo and try GPS only next time.

[LaPerouseBay]

Here is Garmin Instinct, GPS only.

Gopro11 data was smoothed by averaging the nearest 10 data points.

Google says Garmin watches switched to a better GPS chipset a few years ago. 
The new chipset includes the Beidou constellation.