1 Strange fitness results from first run without phone with brand new AW series 3 gps.

Discussion in 'Apple Watch' started by kofman13, Mar 22, 2018.

  1. kofman13, Mar 22, 2018
    Last edited: Mar 22, 2018

    kofman13 macrumors regular

    May 6, 2009
    Hey all, recently posted here a lot debating whether or not to upgrade from S0 to S3 and i got the S3 GPS today and its an amazing watch so far. Literally just came back from a run just now after unboxing and charging and setting up and i had some weird results regarding gps performance.

    i got the GPS model, non cellular.

    I have a route in my neighborhood ive been taking for the last month with my former S0 watch and my iphone X on an arm band to accompany me. Some notes about my path i learned when running with S0/iphone X. The first straight path before turning a corner onto another street is always .75 miles. I am just starting to train so my distances are short. I usually do 1.5 miles. So i get to that corner and my watch always tells me halfway point reached and I turn back and go the same path i came which gives me another .75 miles and thus completing my 1.5 mile distance.

    Today with my new AW 3 GPS, i ditched my phone and set a run distance for 2 miles. I started the activity the second i left the door of my building and started running. I took my usual route. Noticed that I reached .75 miles 1.5-2 blocks earlier than i always did with my S0/iphone. Another weird thing was that once i got to the halfway point ( 1 mile), i turned back right away. Got back to my building with 1.95 miles, when i should have had 2 miles completed since i took a path for 1 mile and turned back right away and did 1 mile back. SO it was off by .05 miles?

    And lastly another weird thing was my running pace tracking was not updating often it would just sit at 8'05" for 10-15 seconds then shoot up to 9', then stay there, then go down to 8'45". and when i turned around after the halfway point it shot up to 24'56" even though i never slowed down my speed, i just turned around.

    Is the GPS in the apple watch just really weak or not updating as much as the iphone? I was assuming the performance would be dependable because in reviews, the GPS signal in the apple watch 3 without a phone nearby was apparently as good as the best Fitbits and comparable to Garmin watches.

    AFTER THOUGHTS: Perhaps i didnt wait for a proper lock? I am looking at the route on the map in the fitness app on the phone and it shows my start point was like almost 2 blocks later and a little north from where i started running. ( i started running right away as i left the door and pressed start on fitness).

    Perhaps i didnt let it get a good lock before starting the run? so when it locked i was already running and it got confused?

    ANOTHER NOTICE: i looked at the route and the color on the trail in apple fitness app is just a rainbow colored zebra, meaning its showing that i went from fast,medium,slow and back and forth literally every 20 feet when i ran nonstop and was definitely not changing my speed
  2. sclawis300 macrumors 65816

    Apr 22, 2010
    I’ve have the LTE version so I don’t know if that makes a difference. The different paces seems very odd for sure. I ran 1.5-2 miles on a track and it was off by .04 at the end. I was pretty pleased with the result. I usually run a loop 3-4 times and it doesn’t ever seem to register the same from day to day.
  3. mk313 macrumors 6502a

    Feb 6, 2012
    I'm guessing that it had to do with the GPS lock (or if you run in an area with lots of tall buildings, the GPS could be getting blocked when the phone wasn't). The other thing about GPS is that there are some kind of coordinates that get downloaded to your phone/ watch every few days that helps the device lock onto signal faster (I'm not sure of the technical name, but someone on here posted a really detailed explanation a few months back). It's possible since you just got the watch & synced it up & left that maybe the device hasn't had time to download that datafile, so it took longer to get a GPS lock.

    The GPS on my watch (series 2) has been rock solid since I got it. I'd give the watch another couple of days to make sure that everything had a chance to update.
  4. dallison13 macrumors regular

    Sep 10, 2014
    you need to calibrate that new watch first! I think a 20 min walk in the beginning is recommended before you run.
  5. MJ22 macrumors regular

    Oct 3, 2017
    Mine seemed to improve in accuracy after the first few runs outside with it. Now it’s pretty dead-on with my usual mile markers that my Garmin would mark.

    It’s a GPS that bounces back and forth with satellites so try to remember no unit is perfect, no matter what brand. The science itself will always be slightly variable.
  6. Resqu2 macrumors 6502a

    Apr 23, 2011
    Op I’m sure it will get better as you use it. A few or more 20-30 min walks will really help to.
  7. Pseudo-Fed macrumors 6502

    Jan 28, 2017
    ^^This. I found also that my AW distance on 2-4 mile runs, as well as it's average pace was more erratic vs my seasoned Garmin F3 at first. After a few runs it improved. No device is perfect and even when running a perfect 3.107 mile (5K) course, I still see Garmin and AW off and over/under by .01 to .03 miles on a given day. Consumer GPS products just don't have the accuracy of military, surveying GPS, etc.

    As for turning around, you have to run an extremely wide loop in your turn to not see a decrease in pace. Just running around a light pole or from one side of street to the other will not prevent it. There's just not enough separation in the satellite trackable points in our consumer GPS units.

    I do find that my pace chart with AW looks more like a porcupine with frequent spikes and drops centered around the average vs. Garmin, which smooths its data more. I've had Garmin and AW have EXACTLY same distance and pace only one time. Rest of the time they are 1% or so apart (.01 per mile in either direction).
    --- Post Merged, Mar 27, 2018 ---
    Calibration has nothing to do with GPS accuracy. I believe the only issue with GPS accuracy is "lock" which I believe after a few times turning it on outside it caches the locations for later retrieval. Calibration only has to do with teaching the AW your strides per unit of distance, for which it needs GPS outdoors to capture. This will help with accuracy of INDOOR treadmill activities. Calibration occurs automatically when using GPS outdoors so that your INDOOR activities can be more accurate.

    Note: for indoor runs to be accurate to pace and distance, you have to do OUTDOOR activities with GPS turned on at all your likely paces. I typically run an 8:50 to 9:30 mile (old guy), depending on how far I'm going. AW is doing calculations of your strides (arm swings) vs that GPS-recorded distance and calculating a stride length. Then when you "stride" indoors it does the math to get distance and speed/pace. If you vary your indoor pace from those tracked by AW outdoors, it will not be accurate indoors.

    I do wish Apple allowed us to "edit" the workout data before saving--especially indoors. Garmin has started doing this for indoor runs on their units. You can enter known data like distance from a treadmill to get Garmin to reflect what treadmill does before saving. Treadmills are notoriously uncalibrated and off, but at least if you run on the same one you can have consistency in your data.

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