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Forerunner 935 GPS Accuracy/Performance

Let' get it started. Post your GPS results and comparisons.

FR935 vs F5s
FR935 vs FR920
FR935 vs FR23x

Thanks!
  • Possibly although I have never found the 935 to be significantly out on distance and often with trail running you have no real idea how far you actually went anyway.
  • I've only a couple of runs on the trails with mine and the distance has been within cooee of the 920s that have been with us. And that's under some quite dense tree cover.
  • Doesn't it make sense that the FR935 would report a slightly shorter distance when it tracks things smoother? I mean, garmin will try to correct uncertainties and all but it's hard to say which one is the proper one... The only way would be to properly measure a track using official ways and see how the watches do on those extact tracks.
  • Hi,

    You can see it on the following tracks. The normal distance is 10,0km. The distances with the FR935 were shown also with 10,0 and 10,05km on Garmin Connect. But the tracks were 200m longer (100m by a dertour and 100m at the end).
    As Comparison you will find old tracks from the 310XT and F3.
    I know that the GPS accuracy at consumer products is +-2%, but the shown track on the map is ok. Only the calculated distance is too short.
    (The track with 1s recording was the shortest track.)
    Can you confirm that the tracks are shorter?

    http://www.mygpsfiles.com/app/#etVdKwWr

    Regards,
    Christian


    Yes! I've observed that Garmin Connect usually corrects (or calculates) the distance to remove the bias of wobble or twitch from raw GPS data. So, the corrected distance will be a little shorter than raw GPS route. If you finish a run and get the distance of 10km in Garmin Connect, you may see the distance changes to 10.1 or 10.15km after you upload the raw GPS data (.gpx or .tcx) to the website like mygpsfiles or runkeeper.
  • Other way round I think? GC just accepts the distance recorded on the device for a normal activity so your device and GC match up. If however you export that file as GPX then these 3rd party apps are probably just using simple "dot to dot" calculations of distance and so likely to get slightly longer distances.
  • Former Member
    0 Former Member over 7 years ago
    The watch does correction on the fly during activity. I've had one run where the GPS track on my F5 was a total mess probably bad satellite cache or something. The total distance was nearly 4% too long according to GPS path. The watch still managed to narrow this to just 1% error.

    Thus I think it's pointless to lose your sleep if the GPS track is other side of the road or even jumps occasionally if even such a bad track I had can produce still usable result although I still prefer the error to be under 0.5% if possible, which it most of the time is.
  • Two runs on the same course now; one with the 920 (13.6km) one with the 935 (13.7km). No complaints there. Tracks look ok too.
  • Hello, I can see it exactly same way as Nicoloco, I'm very happy about features, but GPS accuracy is very disapointing. Just ligt tree cover and instant pace goes immediately 30 or more off way. When clear view to sky, performance is great, but overall nothing much. Even thinking of returning FR935 / For that money I was expecting better results.


    After some more testing and comparing I must aplogize to FR935. I had oportunity to compare GPS performance against Polar V800, which I still find as one of most accurate GPS watch. And my conclusion is:

    - When open view to the sky both watches are excelent However I found FR935 a bit better.
    - When tree cover (even light) FR935 start to show a bit slover actual pace sometime up to one minute slover. But when run out of tree cover, actual pace get correct immediately, why Polar take more time to get right again.
    - km marker and lap pace are practicaly identical on both watches (+/- 2 sec)

    So my final conclusion is: Such a light watch like FR935, with real battery life almost 24 hrs, with such a features and GPS performance are great.
  • I've been eyeing off Stryd, but $$ has prevented me currently.
    Have you any experience with Garmins Footpod? for mostly distance tracking?

    It's a lot cheaper, and I can get it locally.



    The Garmin footpod was okay, and I used it for pace only. With my running form, I found that the calibration worked well within a 1min/mi zone. Because of that I used 3 calibration factors depending on the estimated pace goals of my workout.

    I haven't had any issues with Stryd. It is unbelievably accurate despite my running form, weight, or fitness level. Like I said before, I only use GPS (smart recording, no GLONASS) to show where I went. Pace and distance is recorded by the Stryd. Running by power is also very interesting. If you love running and want accurate and usable instant pace or power, the Stryd is a good investment.
  • Former Member
    0 Former Member over 7 years ago
    GPS accuracy disappointed me. I?ve compare some trainings with my Polar M400 (which costs less than a fourth of the Garmin 935). I had gps+glonass on at this training.
    I do a second test today on the same track without glonass.

    red M400
    blue FR935

    a good source is also http://fellrnr.com/wiki/GPS_Accuracy FR935 is in the lower fourth of all tests...

    i seriously thinking of selling it...
    ciq.forums.garmin.com/.../1239418.png