Blaze GPS - Map Accurate, Distance Wrong

[Moebius01]

Since I've had my Blaze, I've used both the Fitbit exercise mode and RunKeper to track my runs.  The Fitbit has been on average .06 miles off, but it ranges from .06 to a worst of .23 miles per mile tonight.  I start, the exercise in Fitbit, see it connect to GPS, then start both it and Runkeeper simultaneously.

Here's where it gets weird.  Looking between RunKeeper and Fitbit, the maps are nearly identical.  Tonight's run, measured by both my car and mapmywalk show as 1.1 miles.  Runkeeper shows 1.09 and Fitbit shows .86.  Again, the maps between the two apps are identical, but it's like Fitbit calculates distance incorrectly or something.  Is this common, or something I'm doing wrong?

[OleMarius]

This is super common. I get average of like 5-8 km off when im out jogging. Like last weeks run i had. Went out for a jogging on a rute of 6 km, the fitbit shows 11,25 km. 

THe odd part. i Use google map log to get the real distance, fitbit use google map, and add 5250 meter extra for my run.

[Moebius01]

Pretty annoying too.  It's much easier to take a quick look at the wrist to check distance than fishing the phone out of the pouch.  If it was at least consistent, I could work with that, but it seems to be all over the place.  Even the same route.  The night I posted the original message it came in at .86 miles.  Three nights before the exact same route (same map result and everything) came in at 1.04.  Seems there's no rhyme or reason.

[FerdinandFitbit]

Hey there guys @Moebius01 @OleMarius. Good to see you in the Community!

Whenever it comes to GPS tracking, at least two dozen GPS satellites are constantly in orbit around the Earth and broadcasting data. All GPS devices, in this case, your Fitbit Phone which connects to your Fitbit  Blaze, requires a direct path to these satellites in order to receive their radio transmissions. If the signal is being blocked—either because you're underground, near many tall buildings, or as a result of atmospheric effects—GPS will not work. Thus, whereas GPS gives you a more accurate measure of distance than step counting alone, the actual accuracy depends on both your environment and the weather. Keeping an eye on your sorroundings will help since in case you're sorrounded by a lot of trees or tall buildings, the tracking might vary.

Hope this helps. Let me know if you have any more questions.

[Moebius01]

Note though that in this case, the problem does not appear to be GPS signal strength but the calculation the Fitbit engine is using to measure distance. Runkeeper running simultaneously on the same phone as my Fitbit connects to records the distance fine (matches a known measured distance as well as my wife's phone).

[bbarrera]

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@Moebius01 wrote:

I start, the exercise in Fitbit, see it connect to GPS, then start both it and Runkeeper simultaneously.

Here's where it gets weird.  Looking between RunKeeper and Fitbit, the maps are nearly identical.  Tonight's run, measured by both my car and mapmywalk show as 1.1 miles.  Runkeeper shows 1.09 and Fitbit shows .86.  Again, the maps between the two apps are identical, but it's like Fitbit calculates distance incorrectly or something.  Is this common, or something I'm doing wrong?

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@FerdinandFitbit the phone GPS is working fine, as Moebius01 is using Blaze and RunKeeper simultaneously and:

- RunKeeper: good mileage

- Fitbit Blaze: bad mileage

- maps are the same

This has been reported many times, and at least one Fitbit moderator has stated that its likely a problem with some loss of GPS data on Blaze because bluetooth was interrupted.

[AlejandraFitbit]

Thanks for the information @Moebius01 and @bbarrera. If at the moment of doing the exercise you have the wifi on, I recommend turning off wifi when you're using connected GPS to improve the experience. In this way your tracker might be able to register your miles correctly. You can also check the Things you can do to make the Blaze more accurate post, where our friend @bcalvanese is providing really good tips. 

Let me know the outcome. 

[lkocin3784]

I too have had this problem when recording mileage. I use the View Ranger app, which connects to GPS, to track my route, along with Fitbit. My mileage when compared between the two devices is anywhere between .25 to .50 miles off (the Fitbit continually having the deficit). But here's where it gets tricky...when hiking the same distance with 2 other friends, both using Fitbit products (Blaze and Alta) my mileage is still off. I have done master resets and have gone as far as having the device exchanged out for a new one. Any answers for this?

[Giampi71]

It appears the problem appears because the connected GPS is used only for mapping while the distance/pace relies only on step detection. This shall be considered as a huge bug by Fitbit and hopefully next imminent firmware update will fix it.

I wonder if the issue was introduced only in the recent updates, I can`t verify it since I got by Blaze only 10 days ago but if this bug is not issued I will sell it straight away.

[Tyrian]

I too have always experienced the same behaviour mentioned here although the difference for me is that in general the Blaze seems off by a consistent amount.

I also have a FitBit surge and that does seem to get the distance right. Generally over a 3km run I find the Blaze will record about 0.2 km short even though if I compare the map generated by the Surge vs the Blaze they show virtually identically. (haven't ever tried them on the same day as I don't trust them to sort out the double steps)

Given the margin is generally pretty small I haven't worried about it too much, although on the odd occasion it is worse.

[lkocin3784]

No, this a reoccurring issue...in fact I had my Blaze go thru 2 master resets and then replaced because of it. I found the issue in the inaccuracy with the distance when using the fitbit along side an actual GPS mapping app. I found there to be a consistent difference of between a 1/4 to 1/2 mile difference (fitbit short compared to app).  I also verified this distance difference with friends who also use fitbit products.  Support  couldn't explain the reasoning. Good luck trying to fix!




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[OleMarius]

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@FerdinandFitbit wrote:

Hope this helps. Let me know if you have any more questions.

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WOuld be lovly to see a software fix on the fitbit app for this. It is infact not about signal, amount of satelites. It is the software who is inacurate. Google Map is darn streight on the distance while Fitbit whom seem to use Google Map add extra distance. Blaze does not work, it is simple as that. 

[VikSteps]

@Moebius01 You are absolutely correct, it is the calculation used by FitBit which is incorrect. It can be proved by using FitBit's dataset and recalculating the distance.

Export your activity as a TCX

Use http://tcxtools.com/tcx/distance/ to recalculate the distance

Open it up in Notepad++ or similar, the recalculated distance is near the top

[bbarrera]

@VikSteps mentioned this in another thread, just setup Fitbit-to-Strava sync to have connected-GPS runs/walks/rides sent to Strava, and you'll see accurate distance in Strava.

[VikSteps]

@bbarrera Just for those following this thread, this was my reply:

That didn't work for me, Strava seems to trust the distance coming from FitBit, so overall distance is wrong but your segments are correct! If you had segments for the whole distance I bet the sum of those would be greater than the distance.

Due to a bug in Strava you cannot export the TCX from FitBit, fix the distance and re-import it with a new ID, it will ignore the distance and give you 0.0km, so you end up in a worse position! (segments still correct though)

[bbarrera]

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@VikSteps wrote:

Due to a bug in Strava you cannot export the TCX from FitBit, fix the distance and re-import it with a new ID, it will ignore the distance and give you 0.0km, so you end up in a worse position! (segments still correct though) 

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I'm not seeing any Strava bug.

This morning I exported a TCX activity from Garmin bike computer, used the tcxtools website to "fix the distance," and import the new TCX file into Strava:

https://community.fitbit.com/t5/Blaze/Blaze-Inaccurate-Distance-Even-W-GPS/m-p/1962050/highlight/tru...

[Likestoplay2]

Does anyone know if Fitbit has fixed this?  Did the new update fix it?  Blaze is not accurate on pace and distance when starting the activity from the Blaze.  Customer service could not get it working correctly for me.  Tried two different Pebbles.  25% inaccuracy is not useful.

[VikSteps]

No it's not fixed it's consistently wrong.

Run's - it tends to go over, for me it's about 80-200m, not too much of a big deal

Bike rides - it is always under the distance, can be anything from 1k to 3k under

The underlying dataset seems to be ok, just the distance calculation is not!

Restarting the watch seems to get it closer to the real distance but this is not reliable at all, you're better off just using another app on your phone or getting a Garmin if accuracy is important.

[Hickman96]

The blaze uses your phone gps in order to track the mileage. if your phone is on you, which it has to be in order for this function to work, and has a solid signal then shouldn't your fitbit blaze mileage match whatever the mileage tracked on your phone is? I ran last night with the intent to run 3 miles. I ran until my blaze reached that mark. I looked at my phone and my runkeeper app was at 2.75 miles. I was on a trail that goes around a wide open soccer field with very few trees and it was bright and sunny. The disappointing fact is that the blaze (which isn't especially "cheap") does not seem to keep signal with your phone - has nothing to do with satelites since the blaze doesn't directly have gps capabilities and uses your phones capabilities. This is doubly frustrating for those of us using it for training purposes. 

[Likestoplay2]

I was told the blaze doesn't use the phone to track distance.  It use the phone only to map the route.

I've moved on to an Apple Watch Series 1.  Its much more accurate than the Blaze in measuring distance and pace.  The heart rate monitor is just as good.  Battery life sucks, but the distance and pace accuracy is worth it.