GPS distance totally wrong on Charge 3

[BertilDator]

Was doing cross country skiing, and set activity to "run" (as there is very limited activity list). Had phone connected, and got perfect GPS route on Fitbit activity. However, all the splits are way off. Total distance in Fitbit shows 4.8km while real distance was 7.5 km (I know the route, and even double checked via ontegomap.com).

How can Fitbit calculate distance so wrongly even though the GPS route is perfect on the activity? I repeat, the tracked route is 100% correct on the Fitbit activity in question, so there is no disconnections, or trees, or anything between the phone and GPS satellite, nor between phone and Charge 3.

Is Fitbit using GPS route for distance calculation when assisted GPS is enabled during "Run" activity, or does it STILL use stride length?

Should I use "Biking" activity for XC skiing to get accurate distance based on the GPS route?

[HansimGlueck]

@AdamH0 Thats exactly the problem I have again since some weeks/months.

But at least your distance is quite close. I had a run recently that had 10.26km according to strava and 6.73 according to FitBit....

[AdamH0]

Interestingly I did two 5km parkruns on New Years Day, and they came up almost exact. 5.00km and 5.02km.

Other than everything having had a reboot, there's not been any version number changes or app updates etc.

The GPS tracks are a bit wavy, which I suspect is the phone GPS. So it's possible the apparent accuracy is coincidental. 

[ahof]

Just had this too. My regular 10k run marked as 12k by Fitbit Charge 3. It was connected to phone/GPS in my pocket the whole time, and the track looks correct on the map, but the distance is overstated by 20%. Firmware version 28.20001.63.5

[AdamH0]

Then my next 5k parkrun came in at 4.53km... causing the watch to greatly underestimate my pace.

Interestingly if you export the gps trace from fitbit and load to strava you can get strava to re-analyse the distance and it came up with 4.98km.

Currently the watch is useless for actually telling me anything useful during a run as I just cannot trust any of the data. (Other than the duration...)

[Sylpoy]

I face the same issue here since last september with my C3 sync to an Honor View 20.

This morning I ran with my work phone, a Moto G5s Plus and the distance was absoluty right.

It seems that the issue comes from the phone. I remember I installed (and deleted) a GPS fix app a few month ago on my Honor, maybe it is the problem.

I restore my phone to default setting this morning, I'll tell you if the problem is fix after my next run.

[Fit_bit3wtf]

I wrote on this post a while back about how poor my fitbit 3 was working.

I find it amazing fitbit have failed to solve this issue.

I am a seasoned runner and this device under records distant and so shows
poor pace as a result. The inaccuracy and unreliability of its tracking
means I have gone back to using just my phone.. and wow its alot better.
Back to Samsung I guess, thanks fitbit.

[SunsetRunner]

It is even getting worse and worse. Regretting a lot having bought the charge 3. Compared to fitbit disaster my phone with nike run app works perfectly fine.

Last run with fitbit: (no I was not drunk 😜  )

 

Updating Media

[BrandonW92]

Currently working for my third charge 3 devices since October to be delivered, previous two have had the same issue with not tracking correctly and I'm not holding much hope of this new one working correctly. 

Place where I brought it from want a code from Fitbit before they will do me a refund, I just want my money back so I can buy a Garmin 

[Sylpoy]

Hi. I have exactly the same issue since last september.

What phone are you using? I have a Honor View 20.

[SunsetRunner]

I have a galaxy note 9

[HansimGlueck]

Galaxy S10E

[BrandonW92]

I have the Samsung S10+

[djjkfno]

Samsung galaxy s9

[djjkfno]

Is there someone with the same issue on iPhone

[f1oyd3]

Some further testing still leaves me scratching my head. 

When I use the charge 3 to initiate the run (everything connected, phone in pocket) the gps is still way off.  I thought I'd give it time to "adjust" like fitbit states it will, haven't seen any difference after several runs.  I should note, the gps map the charge 3 pushes to strava looks exact, but the distance is all jacked up, which in turn messes up the pace.

I did a few runs with both the charge 3 recording and the strava app recording simultaneously.  When I do this, the charge 3 actually records the correct distance!  This is a mystery I need to explore further.  Maybe there is some permission that needs to be turned on to get the charge 3 to use gps fully.  

Tldr:  charge 3 still sucks, more testing to come, getting closer to buying a garmin.

[ahof]

I recently ran 5km with both the fitbit charge 3 (connected to GPS on phone) and Strava (on the same phone) recording the run. I have exported both runs to this KML file, which can be imported in Google Earth. 

https://drive.google.com/open?id=1fgPAw33mYAtU-wPmEhy2w8UzKYrhp4z6

The Strava track is very close to the actual route I ran, and reports the correct 5.0km distance.

The fitbit track has a lot of the weird zigzag features that other people in this thread have also reported. The raw GPS track from fitbit is actually 6.7km because of all these bumps, but the fitbit reported my run as 4.6km.

Example of Fitbit vs Strava track

Both 6.7km and 4.6km are incorrect distances for the run. Perhaps someone at fitbit could use this raw data to figure out what is happening here.

[Paul_234325]

I have also encountered wonky readings.

I recently did an 11k trail race - so I know the course was 11k. I accidentally paused my fitbit charge 3 for 2 minutes, so expected a 500m discrepancy at most. Fitbit was connected to phones GPS.

My fitbit result? 8.74km... My fitbit sends this data to strava, so I exported the GPX file from strava.

I then measured the distance of this online, and received 10.3km.

So the GPS readings were nearly spot on from my phone, yet wildly inaccurate within fitbit?!

Your app is taking the raw GPS data from my phone, how can the app get it so wrong?

This could totally screw up training, as I can never be sure anymore if my pacing or distances are accurate. Being out by 20% is a huge margin of error.

This issue has been reported by many users over a long period of time, so I will now move on to a different platform.

[vhaasteren]

Update from earlier post:

I ran a half marathon race this week. Turned on the charge 3 running (tap "let's go") while the GPS was showing as connected while I crossed the start port, and I ended it when crossing the finish.

Result: 13.65 miles, with an average reported pace of 7'29". That should read 13.11 miles at an average pace of 7'45".

As small as it may seem *this time*, even a 15" difference in pace actually makes a big difference. Such a crappy tracker

[Paul_234325]

I ran a test today. I started my fitbit and strava at the same time (both using the same phone with same GPS logging).

Google maps estimate for the route = 9.9km

Resuts:

strava = 9.6km
GPX from fitbit = 9.3km

Fitbits recorded distance.... 11.07km!!

So the fitbit overestimated the run by nearly 20% again.

How does the fitbit export a pretty accurate GPX file, but then misread the results from this?

Saying that, being 300m out (when compared to strava) over a 10k run is a poor result anyway. Being 20% out is just taking the piss.

[RiseAndShine]

Google maps distance never ties exactly to the distance measured by GPS in my experience. Now that I use Garmin it measures exactly the same distance as Fitbit (when Fitbit was working). For example, for a 4.4 mile run per google maps, both devices would give me 4.25-4.26 miles. In general, it's pretty normal to see some small discrepancy in distance measured by Google maps vs GPS distance traveled during activity. Garmin is using double GPS systems - I tried with all options and received the same result. In this sense when Fitbit's GPS functionality was working well, it was producing results close to Garmin (note, GPS on Fitbit for biking never worked for me) and as long as it was consistent - it provided valuable info about running session. Now that it's "converting" GPS reading into something 20-25% up or down it's totally unexceptable...  and the fact that Fitbit doesn't do anything about it is just beyond me (and why it's so hard to just use the map results without totally messing up the distance?) I was not very picky about other Charge 3 functionalities that were not working as designed...  even such small thing as alarm clock - was getting snoozed instead of stopped. (Never fixed by Fitbit). However, GPS became the last nail in Charge 3 coffin...