GPS Accuracy

Discussion in 'Apple Watch' started by JasonHB, Jan 4, 2017.

  1. JasonHB macrumors regular

    Joined:
    Jul 20, 2010
    Location:
    Warwickshire, UK
    #1
    Hi,

    I have just purchased an AW2 after having had an AW0 for over a year. I use it along with an iPhone 7.

    I gave my girlfriend my AW0 and she uses that with her iPhone 6S.

    Now, when we both go out for walks together, there is a significant differential in the distance that is logged via GPS between our devices.

    For example, my workout session will perhaps read 4.1 miles yet hers will read 4.9 miles and we have walked the same distance.

    My questions are these -
    Firstly, why such a difference, this is consistent whenever we walk together? I would have thought that the GPS in both phones should be pretty close.
    Secondly, which is likely to be more accurate? I assume that if I walk with my iPhone, then the watch will use that for GPS by default.
    Thirdly, should I even care about this? Probably not, but it is just a minor irritant and I don't understand why this is

    I look forward to your educated responses.

    Thanks in advance

    Jason
     
  2. gwhizkids macrumors 68020

    gwhizkids

    Joined:
    Jun 21, 2013
    #2
    Are both watches calibrated for outdoor walks?
     
  3. Julien macrumors G4

    Julien

    Joined:
    Jun 30, 2007
    Location:
    Atlanta
    #3
    OP said both were using GPS so calibration is irrelevant. Calibration is for use without GPS.

    While the differences stated are a little out of spec, in general 5% error is not unusual for consumer GPS. So if you went 5 miles one could read 5.25 and the other 4.75 and be within 'normal' deviation.
     
  4. Resqu2 macrumors 6502a

    Joined:
    Apr 23, 2011
    #4
    Me and my wife walk a lot, both S2 watches, I carry my phone and she don't. They are very, very close. On a 3 mile walk we are within .01 miles of each other. I'd not like mine being off by that much but don't know what to tell you to do about it either.
     
  5. CobraPA macrumors 6502a

    Joined:
    Mar 12, 2011
    Location:
    Lansdale, PA, USA
    #5
    Are your walks fairly straight? Or do they twist a lot? Oddly, gps distance estimates tend to get worse the more your walk varies, and also with the quality of the gps coverage. There are a bunch of threads about this on multiple forums.
     
  6. raqball macrumors 68000

    raqball

    Joined:
    Sep 11, 2016
    Location:
    California
    #6
    Does anyone know the rate the watch records at?

    My Fenix 3 and Edge 820 (most gamin's) have setting for SMART or 1 second recording..
     
  7. DeNachtwacht macrumors member

    DeNachtwacht

    Joined:
    Aug 2, 2012
    #7
    The important thing here is that the S0 needs calibration first (see the running workout on the official Apple manual). I can imagine that you did a complete reset of the watch before giving it to her, so I suggest to do a couple of more runs and look if the difference is the same or that it diminishes (which would seem logical to me)
     
  8. Julien, Jan 6, 2017
    Last edited: Jan 6, 2017

    Julien macrumors G4

    Julien

    Joined:
    Jun 30, 2007
    Location:
    Atlanta
    #8
    Again post calibration is ONLY for using without GPS (like indoor treadmill). When using with GPS the :apple:Watch is always calibrating dynamically.

    https://support.apple.com/en-us/HT204516
     

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