Connected GPS failure

[hawkyou]

I walked Bloomday a 7.5 mile race today. I used the exercise "walk" connected GPS feature. It only tracked 6.8 miles and the map is missing a large stretch. Not sure why this happened. Really sucks.

[bbarrera]

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@Colinm39 wrote:

This appears to be a Southern Hemisphere problem but doesn't explain the Surge which was on my RH wrist.. The phone in my RH.  So position wise the devices were on the same track.

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I've seen some posts about that hypothesis, I understand your math although connected GPS distance errors have been reported by folks in Northern hemisphere as well. And connected GPS errors are both positive and negative.

What I find interesting about your 1.21km walking test (distance = steps * stride):

• 3.3% worst case distance error with Fitbit One (-2.5%, -3.3%, and -3.3%)
• 5.8% worst case distance error with Surge (-5.8% and -5.8%)
• 7.4% worst case distance error with Blaze (7.4% and 5.8%)

Step counting is a basic Fitbit feature, somewhat surprising to see such wide variation between trackers.

You previously reported the following errors with Blaze Connected GPS:

• 10.7% distance error on January 2
• 10.7% distance error on March 28
• 1.7% distance error on March 29

Another large variation. I think the more interesting test will be to compare Blaze connected GPS to a phone app using the same GPS data, at the same time, on multiple walks and different days. Distance errors have been both over and under, and in the case of say 20% less distance (e.g. Blaze says 0.8 miles, actual is 1.0 miles) the interesting thing is that some folks have Fitbit-to-Strava export setup and Strava gets the correct distance. This suggests that under-reporting on Blaze is due to missing GPS trackpoints - that the Blaze throws out short distance segments when there is missing GPS data, thereby undercounting the actual distance. I've seen evidence that Fitbit throws out short segments if it senses no steps (e.g. on Surge when riding a bike), and others have reported it. So it seems reasonable to believe Fitbit tries to correct distance estimates when either steps aren't detected (easily happens on wrist trackers) or missing GPS trackpoints (bluetooth issue, or Android/iOS didn't send everything). The missing GPS trackpoints because of temporary BT interruption was offered as an explanation by a Fitbit forum mod on this forum, and it makes sense. It doesn't explain when Blaze reports a longer distance, my hypothesis is that Blaze isn't "smoothing" noisy GPS trackpoints like some phone apps.

[Colinm39]

@bbarreraYou explanation is well founded and will help us determine the issues we have.

I will vouch for the non movement and distance. I tested the Blaze on a straight drive in the car for 4.3kms. The Blaze made no adjustments for movement, and all it picked up was 510metres which was my walking to and from the car at home and the parking at the shopping mall.  Otherwise perfect tracking.

[mvan231]

The blaze will not track the distance driven. It is meant to track running
or biking. The distance won't log but it will track GPS coordinates and
show on the map but the distance will show 0 or close to it.

[Rich_Laue]

This might depend on what mode your using yo track the car ride. GPS is definitely used for distance while Biking.

[mvan231]

Maybe! Not sure.

[Rmattson0714]

Hi all, new to this thread and Fitbit blaze, so please forgive me.  I previously hadan Apple Watch, but it broke, so I changed to Fitbit because of all the hr and data features.  Went for a run tonight and blaze stopped at .61 miles, with a map that looked like I cut corners.  When I finished at over a mile I saw that the watch was no longer recording.  Also my pace was off by about 2 minutes.  Not sure what to do as ive only had blaze for less than a week and I like the other app features a lot.  But I need to accurately track my runs!

[mvan231]

Are you using iPhone or android? Also, it does help to have the blaze and
phone on the same arm. Turning off wifi before a run has been said to help
as well but I haven't been turning mine off lately. It does help to wait
until the signal bars are full before pushing the play button.

Welcome to the community by the way! 🙂

[Rmattson0714]

I'm using iPhone.  Weather has been iffy here, so I haven't tried again.  Will use your recommendations this weekend, thanks!

[CrissB]

Well this latest firmware update certainly hasn't fixed my connected gps problems - so disappointed 😞

I'm in the Southern Hemisphere as well, so I'd be interested to know if this is a recognised problem in this region.  My Blaze always measures over the distance I have walk/run, and gets further out the further I go.  The bluetooth connection seems to be stable, and I'm never missing any sections when I view the map afterwards.

I did a test yesterday based on someone else here saying you could run another gps app at the same time - I walked 3km measured through Map My Run on my phone, at the same time as starting a connected gps session on the Blaze.  The Blaze measured the distance as 3.28km (with the inaccuracy increasing as I went).  I don't know how it can be that far out!  

I also thought I'd have a quick look at what the distance would be based on the number of steps it says I took during that session and my walking stride length and this would have been way out as well (3,407 * 64cm = 2.18km).  This would be a great little watch if it just worked!!

[Colinm39]

After another user used concurrent MobileRun and MapMyRun I have just completed that same method and here are the results on my measured course.  No visible dropouts and the pace cannot compare.  But concurrency worked and distance varies again.

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@Colinm39 wrote:

@mvan231Here are the tests for tonight.  I didn't attempt the Polar Beat because the wind was blowing a gale and it would have affected my readings because of the flapping t-shirt on my chest strap H7.

The final image shows the comparison of steps and the Surge GPS with auto stride came very close to the Fitbit One.  The word "manual" means... just let the tracker detect the movement.

Also MobileRun did not sync across and no record so that has a Manual record,  The mapping was from a screen capture.

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[mvan231]

I think we have discovered that the blaze and phone need to be in visible
sight of one another or at least on the same side of the body.
As for the distance and pace accuracy, I have noticed it sometimes seems a
little further than what Strava would record but nothing exponential. I
have noticed before a long time ago when I used MapMyRun that it's
distances were a little off but maybe it has improved. Hard to say.

[Colinm39]

@mvan231 I will go out shortly and try a concurrent with Blaze Connected etc and see what that achieves. I will use the Surge as well.

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@mvan231 wrote:
I think we have discovered that the blaze and phone need to be in visible
sight of one another or at least on the same side of the body.
As for the distance and pace accuracy, I have noticed it sometimes seems a
little further than what Strava would record but nothing exponential. I
have noticed before a long time ago when I used MapMyRun that it's
distances were a little off but maybe it has improved. Hard to say.

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[mvan231]

By doing that I have had about 4 or 5 runs in a row without any
disconnection during the run and the map follows pretty closely to my
route. Maybe a few feet off in one direction

[Colinm39]

@mvan231 Have you achieved that by having your phone and Blaze on the same side of your body?.

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@mvan231 wrote:
By doing that I have had about 4 or 5 runs in a row without any
disconnection during the run and the map follows pretty closely to my
route. Maybe a few feet off in one direction

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[mvan231]

Yes that is correct. The info is further up in the thread that we did for
testing and troubleshooting. I wear blaze on my left wrist so now I wear
phone on left bicep and haven't had issues since switching from right arm
to left arm.

[Colinm39]

@mvan231Just back from a simple 800 metre walk.. Surge and Connected GPS Blaze,. Only 20m different extra on the Blaze which is my small amout of East/West and the majority was North/South.  No disconnections.

Because I was doing other testing earlier I had to restart the Android because the Blaze couldn't find the phone.

[Glennbest]

mvan231 fitbit will never solve the problem, I got the same message over and over for 6 months two years ago until they offered a refund. 

I reckon they know what the cause is and the fix is not economically viable; they sell enough of them to people who don't care, are unaware of the problem or don't experience the problem to cover the few refunds they are forced to provide.  Unless you are a rusted on fitbit user who's not worried about the problem ever getting resolved I'd get rid of it and try something else.