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GPS Accuracy - total distance

thanosm
over 6 years ago
I got a Vivoactive 3 in October and I noticed that the pace of my runs appeared to be lower than what I was used to.

I tried running with the VA3 on one wrist and a Forerunner 210 on another, and an iPhone running Endomondo or Sports-Tracker, and the VA3's total distance was always lower by more then 7%. Using GPS+GLONASS and every minute recording did not seem to improve things.

Here is an example:

Vivoactive 3 5.71km https://connect.garmin.com/modern/activity/2344389458
Forerunner 210 6.25km https://connect.garmin.com/modern/activity/2344398396
iPhone 6.34km https://www.endomondo.com/users/24403395/workouts/1035487642

Checking minutes 5:24, 10:48, 20:38, 23:02, 32:40 on the map, it is clear that the other devices are more accurate.

Garmin were kind enough to swap my device, and in the meantime the firmware version was updated. The new results were better, but still off by about 4%-6%.

Assuming that I wouldn't get two problematic devices in a row, and since I haven't read of any widespread issues with the VA3's GPS, the only reasonable explanation was user error.

I tried several things and the one change that seemed to work was to change the orientation of the VA3, having the button on the left (while wearing it on the left hand). I've done two tests so far and the total distance discrepancy between devices is 2.6% - 3.1%. Moreover, looking at the map, it is not clear which device is more accurate, since the VA3 is now visibly more accurate in some segments (and less accurate in some other segments).

This is from today:

Vivoactive 3 7.09km https://connect.garmin.com/modern/activity/2410234674
Forerunner 210 7.31km https://connect.garmin.com/modern/activity/2410261099
iPhone 7.27km http://www.sports-tracker.com/workout/thanosmarkousis/5a4bc46dc3d639076578254c

I think that, at this point, performance is reasonable for a consumer device. I'm curious though if others have tested the VA3 together with another Garmin device and found any differences in the total distance and the accuracy of the trail on the map.
  • 0 over 6 years ago
    I went for another run today, longer but with fewer curves, and the distance recorded by the three devices was very similar:

    Vivoactive 3 10.15km https://connect.garmin.com/modern/activity/2415936320
    Forerunner 210 10.23km https://connect.garmin.com/modern/activity/2415959449
    iPhone 10.28km http://www.sports-tracker.com/workout/thanosmarkousis/5a4fa9a2f1757207725600a3

    The difference between the two Garmin devices is just 0.8%. Furthermore, looking at the trace on the map, the VA3 was possibly more accurate overall.

    So it looks like the orientation switch brings the performance of the VA3 to the same level as other Garmin devices. Having the button on the left is a very minor inconvenience, so for me it's all good.
  • 0 over 6 years ago
    Yes, I agree.
    As I mentioned in my thread reversing it brought the difference down to a tiny 0.01 miles for me over a 6 mile route as opposed to 0.12 miles before.
    I'll be running 15 miles tomorrow with both the VA3 and VA so I'll know for sure after that.
    Thanks for the suggestion.
  • Former Member
    0 Former Member over 6 years ago
    I'm not sure how changing the orientation of the button would have any affect on the GPS. It's far more likely that there was a better GPS signal the second & third time around. I could be mistaken, but I think it would take a whole lot more comparisons using the watch both ways to come to any conclusion.
  • 0 over 6 years ago
    My suspicion is that the antenna is at the bottom of the watch with the button to the right, revering it puts the antenna at the top.
    I did 6 runs before I reversed the watch, there were significant differences between the VA and VA3 until the day I ran with it reversed when the two were then bang on the same.
    I have enough proof of poor tracking with it not reversed.
    Clearly I need more runs with it reversed, if it turns out it was a one off I'll certainly post that up here.
  • 0 over 6 years ago
    0.06 difference today over a 15.5 mile run compared to 0.19 miles last weekend
    This was a much tougher route for the watch too with at around 1 mile of continuous tree cover compared to my other routes which only have sporadic tree cover

    VA3
    https://connect.garmin.com/modern/activity/2417455461

    VA
    https://connect.garmin.com/modern/activity/2417447667
  • 0 over 6 years ago
    I'm finding the GPS accuracy of the VA3 to be off as well. Yesterday I wore my VA3 on right wrist and FR630 on my left. The VA3 was a off by ~1.2 miles during 50K race. The pace was much more erratic as well during the event. While the FR630 is much more mature from a software perspective, I had hoped for a little more parity between the two watches.

    The course did have slight tree cover which makes me wonder if the VA3 was using other measures, like stride/cadence, to estimate some of the miles.


    VA3 (29.7m)
    https://connect.garmin.com/modern/activity/2418176307


    ForeRunner 630 (30.9m)
    https://connect.garmin.com/modern/activity/2418295900
  • 0 over 6 years ago
    I have had my Garmin Forerunner 235 for a year (previous Garmins before that), and since 1/1/18 I've found that it adds a "squiggle," if you look at my running route, of about .1-.3 mile onto my distance. This usually occurs around 4 miles too, which is weird. This has happened now on three of my running routes that I know well. Suddenly they're coming in at higher total distance (and thus faster pace), with the weird squiggle addition in the middle.

    I have the GPS tracking set to Glonass + GPS.

    Also, the current Garmin Connect interface on my Mac laptop doesn't seem to have a way to look at the maps of runs or courses. Where did that go? I have it on Mobile on my iPhone, but the courses should be visible from the activity data.
  • 0 over 6 years ago
    I did an out and back run today, reversing the VA3 orientation at half way fully expecting the return run to show a big difference to the VA, it didn't.
    The VA showed 3.04 miles in both directions, the VA3 showed 3.02.
    I've measured my run on mapmyrun, which I assume gives an accurate measure and the VA is 0.1 miles out on a 6 mile route anyway.
    I think I just need to take it for what it is and move on now.
  • 0 over 4 years ago in reply to valley01

    I recently upgraded from the VA HR to the VA3.(Christmas special, 2019)
    I was very surprised and disappointed that the VA3 consistently returned the same 4-5% short distances compared to my VA HR which had always been spot on (compared to published race distances).

    Putting the button on the left (watch on left wrist) was the easiest potential solution.
    Success!
    My first run in 2 months with the correct distance reported by the VA3.
    Hopefully that's the 'fix', but Garmin could do well to consume this information and act / inform users.