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Has GPS accuracy improved?

I ran a 10,000m race on a 400m running track last night, and lo and behold my Forerunner 935 actually recorded 10.01km / 6.22 miles. My distance / pace accuracy on the track has previously always been poor, with the GPS usually overestimating the distance. I remember doing a 3,000m track race in 2016 and recording 3.26km. Has something changed? I'm very happy as it means I can now rely on the watch for pace info.

My settings are GPS/Glonass with 1 sec recording, with the latest 9.10 firmware. I run in the UK.

0 Sergey_Kessel over 6 years ago

1.
Don't think it is FW that affected (at least I do not see any huge difference). Much more likely it is clouds/ rain/ tree cover/ mood of particular satellite. I record track runs very rarely though.
What I did notice - satellite lock now takes much longer. But it also may be clouds/ rain/ tree cover/ mood of particular satellite/ worldcup in my city/ choose whatever reason you like.

PS: I think that 3.26 was recorded on a bad day (7-10% difference is a lot, I'd say 2-3% is closer to reality (with 5% being maximum).

2.
As for pace - it does round it a lot. And it does wobble a lot. No, A LOT. If you want to rely - invest in running pod (not RD-Pod, running pod) and get pace from there (there is a setting "pace from pod"). It is not reliable itself (unless you calibrate it for a particular pace) but it is a) very stable (no wobbling) and b) changes fast (which is nice for intervals).
You can even skip calibration - I use 1.0 calibration but just know that when I run 6/km it shows 5.50 and when I run 3/km it shows 3.20.
There are reasonably cheap Adidas Micoach pods available on ebay for a fraction of cost of new garmin one (just check it is ANT+ version not BT version).

3. There is very nice "Peter's Race Screen" datafield. Not sure it is useful for 5k-s and 3k-s, but for longer ones it is nice (you push the button at a lap marker and it rounds to a closest mark on your watch. Check it.

0 chunkywizard over 6 years ago

On a track, which wrist you have the watch on makes quite a difference. I believe it is recommended to wear it on the inside arm.

0 scotthunter2 over 6 years ago

I have started to wear my watch on the left so maybe that makes a difference when you are running anti-clockwise in the inside lane. However, the previous degree of error was so large (240m error in a 3000m race) that I'm not sure if this could make all the difference? It's as if the location refresh frequency has increased to more than 1 second.

As for cloud cover, I don't think this makes much difference. I've never noticed the weather affecting distance accuracy on the road. But my Garmin has consistently overestimated distance on the track, until now. Perhaps it's the wrist, like you say.

I do have a Garmin footpod but only use it for treadmill. If you use it on the track you don't get your tracks on the map. I still like to see where I've been on the map for viewing Strava Flybys etc.

0 R_Tellis over 6 years ago

You should still get the map when running on an outdoor track as long as you’re not using the treadmill activity type. The foot pod willgive the pace and distance but the GOS chip is still on.