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Re: GPSMAP 66ST Accuracy?
Posted: Mon Dec 28, 2020 8:51 am
by SFP
I just bought Apple Watch series 6 and made a mountainbiking test run together with my Garmin GPSMAP 66ST.
For tracking purposes (...and this was no mean the main purpose for purchase) the Apple Watch was as accurate as Garmin I could say. Also the heart rate log was surprisingly same from wrist than with Garmin + Heartrate belt.
My finding is (note that only 1 ride) is that Apple Watch seems to track based on time and Garmin is based on several variables. Garmin's rate was put on highest but still the Apple Watch saves more points. The track is smoother. Watch acts in a same manner that the Edge bicycle computers do.
Re: GPSMAP 66ST Accuracy?
Posted: Mon Dec 28, 2020 2:54 pm
by GPSrChive
SFP wrote: ↑Mon Dec 28, 2020 8:51 am
My finding is (note that only 1 ride) is that Apple Watch seems to track based on time and Garmin is based on several variables. Garmin's rate was put on highest but still the Apple Watch saves more points. The track is smoother. Watch acts in a same manner that the Edge bicycle computers do.
Without any tracks to inspect, based only on what you wrote, I suspect you had the Garmin recording controls set to Automatic > Most Often. If you configure the Garmin recording for Time > Once every Second, You will likely get a tracklog that is just as detailed (or more) than the watch.
Re: GPSMAP 66ST Accuracy?
Posted: Mon Dec 28, 2020 3:20 pm
by SFP
gpsrchive wrote: ↑Mon Dec 28, 2020 2:54 pm
Without any tracks to inspect, based only on what you wrote, I suspect you had the Garmin recording controls set to Automatic > Most Often. If you configure the Garmin recording for Time > Once every Second, You will likely get a tracklog that is just as detailed (or more) than the watch.
Thank you! I've used the automatic mode almost last 6 years and never thought about setting it to time or distance. That must be it. I now set it to 2s interval and will look if I get smoother tracks.
Re: GPSMAP 66ST Accuracy?
Posted: Mon Dec 28, 2020 4:48 pm
by GPSrChive
Be aware, when set to short time intervals such as this, if you spend a lot of time stationary it can result in 'spider-web' tracks that require some cleaning up after the fact.
Re: GPSMAP 66ST Accuracy?
Posted: Sun Dec 19, 2021 12:14 pm
by 987
987 wrote: ↑Sun Dec 20, 2020 2:33 pm
Yes. Both units were placed on the point where the known location is, both reported to be 4-5 meters off and both were off in the same direction, actually the readings on the units were closer to each other, than the real location.
This point lies on a small hill top, with a few trees around (very light cover to no cover, weather was cloudy and foggy).
I agree i would have expected a bit better, but even when i have measured against some other point (a few months ago) i got very similar result. At that time it was 3-4 metres. While the GPS/GALILEO/GLONASS satellites move, the precision does change a bit. If one leaves the GPS unit on while at home, one will see how sometimes the pointer is on one side of the house and later it may be on the other.
If i would have stayed and averaged again after a few hours, the results might have become different.
After almost a year, i remembered to try the accuracy against this fixed position again.
This time the weather was sunny and overall reception was very good.
GPSMAP 66st (firmware 9.60, GPSsoftware 2.80, GPS+GALILEO+EGNOS) showed 2.4 m accuracy and the distance to the real location was between 0.8 m and 1.4 m.
When trying the same with GPS+GLONASS+EGNOS with the accuracy given as 3.0m the distance to the real location was between 0.3 m and 1.5 m.