Connected GPS Pace and Distance is Inaccurate

[DanielMena9]

Went on a run today with my Charge 2 on one wrist and Charge HR on my other wrist. Also had RunKeeper to measure my distance. I started my run with about the same number of steps on both FIT devices. 

After the run, my Charge HR had almost 2K more steps than my Charge 2. In addition, my GPS map on FitBit matched my Runkeeper map which is about a 3.5 mile run BUT FitBit pegged the same route as 1.73 miles >.> 

Why doesn't this device work as advertised? I really like the design and feel of Charge 2 but if it can't do its job accurately, all is for not and I will be shorting FIT as it appears to be a widespread issue (I have maps and photos if someone from FIT wants the data).

Moderator Edit: Edited thread title.

[Bibster]

Hi, what's the new release number please? I can't see any release pending on my Charge 2 or on the FitBit website

[Rollerskier]

Release 2.31. Date 9. Jan. I am using iPhone 7 and iOS 10.2 . The previous release was 2.30 from 9. Dec.

Sent from my iPhone

[Bibster]

Hi,

That's an update to the App, not the tracker. I think the issue is with the tracker (I am on Android by the way).

Anyway, I'd be interested to hear how you get on.

Get Outlook for Android

[Rollerskier]

I will do some tests on GPS distance and heart rate this week to see if the App update has an impact on the results and post the results.



Sent from my iPhone

[Rollerskier]

The App update 2.31 did not improve the accuracy of the GPS measured distance.  Distance measured with Fitbit Charge 2 today in RUN mode walking pace was 3,52 km.  The reeel distance is about 3,2 km measured with ther car trip counter.  So about 0,3 km too long (about 10%) 

[hawkeye1952]

Checking your distance by a car is not the same as a gps. I check it using 2 other programs that uses gps and yes fitbit is off.

George Howell Jr

[Rollerskier]

Agree thats better, but I also double checked it with Fitbit, GPS from phone in the front window, while driving(good GPS signals). Fitbit is much more accurate at higher speeds. 40-50 km/hour and it works better and in accordance with my car trip counter.
I got worst results when walking when the speed is only about 5 km/hour. I use Fitbit mainly for walking, roller skiing and in the gym so we do have an issue with Fitbit.

[Bibster]

Here's my reply from FitBit yesterday when I raised the Charge 2 GPS issue with them. It sounds encouraging but then again, if you follow this thread back a few months you'll see these kind of promises have been made before!........

"Our investigations have led us to conclude that this is a minor software glitch which we hope to correct in the next few firmware updates.

Sincerely,

Alejandro P and the Fitbit Team"

[Rollerskier]

Lets hope its not the Needle in a haystack…..and Fitbit does not need a few firmware updates but just 1 more to fix it. We had 2 firmware updates already

[Glennbest]

Derrick it has been 3 months since this post and it's clear this has not been fixed.  Just went for a run and the gps distance is most inaccurate when traveling east-west.  Latest firmware update did nothing nor did the replacement charge 2.  

[Bibster]

I agree and this is acknowledged by FitBit customer service. Derrick, please update this as unsolved.

[hawkeye1952]

Here where I think the problem is. The program that you download and use on your phone. Are directly connected to the phone gps. Where are the fitbit has to send a signal out to your phone. Sometimes it connects sometimes it does.


The signal that comes out from the fitbit is most likely a weak signal. With mine the further I go or faster I go the more it off.


George Howell Jr

[Bibster]

I'm not sure I agree. FitBit has no problem recording accurate route (from phone GPS), only accurate distance. Apps like Strava are able to Sync their GPS route and distance with my Charge 2's heart rate data, so FitBit should be able to do the same. 

I think (as others have also said) FitBit is using an erroneous algorithm to calculate distance, perhaps from number of steps instead of GPS.

[RyanJ5o]

@Bibster wrote:

I'm not sure I agree. FitBit has no problem recording accurate route (from phone GPS), only accurate distance. Apps like Strava are able to Sync their GPS route and distance with my Charge 2's heart rate data, so FitBit should be able to do the same. 

I think (as others have also said) FitBit is using an erroneous algorithm to calculate distance, perhaps from number of steps instead of GPS.

---

Good on you Bibster. That is exactly what they are doing. They override the accurate distance provided by Connected GPS with their calculation of distance from steps.

Why is everyone wrestling with figuring that out?

And why does Fitbit stubbornly cling to that process?

The Fitbit Surge uses an onboard GPS and utlizes it's GPS calculation for distance rather than step count. Why not the Charge 2 when connected to phone GPS?

Hello Fitbit?

[Rollerskier]

I think the problem is the algorithm used to calculate distance based on the GPS-points from the phone that is the issue here.  The raw GPS data points varies in accuracy dependent on where you have your phone and how good you receive the signals from the GPS satelites.  You have the horisontal and vertical accuracy of your position in the GPS-receiver in your phone.  If you use an GPS accuracy App you can see how your position change on the map even if you are not moving.  You have a center and a shaded cirle area and you reel position can be anywhere in the shaded area. That area is reduced when you have good signals.

If Fitbit is only calculating the distance by drawing a strait line between all the raw points and adding up the distance the distance will be far too long.  I dont think this is the case.  They must have an algorithm washing and smoothing the path to be plotted on the map and then calculating the distance betwwen the estimated GPS-points on the map.  This works ok if you drive your car at a city speed and start your Fitbit RUN.  Then you have a longer distance betwwen each raw GPS.

data point from your phone and your direction is more steady forward

However, when you walk you get many more GPS datapoints walking the same route.  And your direction forward is more unsteady based on the raw datapoints.  If Fitbit not have a better algorith when you walk than when you drive a care or a bike in high speed this might be a very wrong distance calculation especilly if your phone sometimes get a bad satelite fix.

This is what I have seen.  Fitbit distance is ok with my car but not when I walk and should be much better when I rollerski.

However, what has changed in the algorith when Fitbit get it mainly right using the Charge HR model and get it wrong using the Charge 2 model?  I used the same phone for both trackers to compare earlier.  Charge HR model distance when walking was quite close to the real distance.  Is there adifference in the matematical alorithm in the 2 models or is it just some programming bugs that needs to be sorted out with Charge 2 since its a later model that is not tested out?

[Eric951]

My distance and my route is typically off. Despite the GPS routes displayed by my Charge2, I can assure you that I have never gone for a run OVER several homes in my neighborhood. I am not spiderman.

[bobby2478]

Out of curiosity, have you done the following test? 

First, start recording the activity through the  Fitbit mobile app on your phone (not from charge 2).  See the map and results.  Specifically use Fitbit app not another app. 

Next, walk the exact same route except this time record activity from charge 2.

If you do these both does the map look similar and is distance comparable? 

These 2 side by side should be nearly identical as the only difference should be the charge 2 interacting with the mobile app vs logging it purely from the app. 

If this looks about the same and GPS route is still jagged then the issue isn't with the charge 2, and the next test id do is record the activity in another mobile app, not Fitbit, and compare to the results you got when recording directly from the Fitbit mobile app.  If these 2 are drastically different then there is a discrepancy with how Fitbit app uses the GPS signal.

[Bibster]

I haven't done the test but whether the issue is with the firmware or the app, either should in theory be relatively simple to solve. 

So why have FitBit failed to solve this?  

My concern is there's a bigger issue, perhaps a fault with the hardware. They tell me and others to be patient because the longer we wait, the harder it is to return our Charge 2s for a refund!

It's frustrating as other than the GPS distance issue, I really like my Charge 2!

[bobby2478]

Specifically because it's been difficult for Fitbit to fix, I suggested the test in my previous post to try and help narrow down the problem. 

The variables involved are the phone your using, GPS signal strength, Fitbit vs other mobile apps, then the charge 2.

To try and narrow down the problem the first thing I'd do is see if the results between activities logged directly from the Fitbit mobile app are the same as what you get by logging from the charge 2. If they aren't, then that additional info could help Fitbit to identify and fix the problem.

I see some people are comparing the results from the charge 2 with another mobile app not Fitbit, that's another variable completely.  Best to start by just comparing accuracy of results within Fitbit only before introducing additional variables. 

[Eric951]

I have some non-fitbit provided information that leads me to believe that the issue(at least for me) is not fitbit related.

I am using a Samsung Galaxy S7 phoneon the verizon network.

When using the verizon navagation app, it often shows me driving through buildings and such. The little triangle icon is 25-50 yards off the road I am driving on. That leads me to believe that the phone GPS sychronization is off.

What phones/networks are others using that seem to be having issues