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.

[rafsanchez]

Ah yes so I don't think that's relevant for me as I am on iOS. There is a "Low Power Mode" in iOS but that's off and both smartphone and FitBit were fully charged.

[DerrickS · Accepted solution]

Hi everybody,

Please make sure that you've updated your Charge 2's firmware if you haven't already. The firmware update includes performance improvements for multisport mode and connected GPS.

Click here for instructions on how you can update your Charge 2's firmware if you havn't updated yet.

[Tom168]

Thanks for giving us the heads up about the firmware update. I've also been having issues with the connected GPS accuracy and the pace information not updating during jogging sessions. Hopefully the update will fix these issues. 

[DanielMena9]

Success! Updated the Charge 2, and went on a run with connected GPS. I would say it was pretty accurate. with steps being around 7K (maybe a little short but passes my error margin).

[fbicking]

I am on the latest firmware and the distance is way off. I have compaired it to Cyclemetter and Garmin 810 and they both agree that the Charge 2 is way off. Over a 4 mile route it can be off by as much as a mile. Does anyone have any thoughts. 

[Tom168]

I went on a quick jog after the update to test the pace and distance accuracy. Both the runtastic app and fitbit app reported the distance as 1.46 miles and the average pace was very similar at 10:15 vs 10:16. However the main issue I was having was with the current pace shown on the Charge 2 display. It was still painfully inaccurate. During the start of my jog it stayed static at 9:46 even though my pace varied from 8:00-11:00. The current pace on the Charge 2 display didn't change until I came to a complete stop. When I started jogging again the pace changed to 9:00 for the rest of my jog. It was never even close to the current pace shown on the runtastic app. Anyone else having an issue with the current pace being inaccurate?

[USAF-Larry]

@Tom168 - The pace displayed on the Charge 2 is inaccurate - a "best guess" might be the best way to describe it - because at the time it is displayed it does not have a solid measurement to base it on.  After the run is completed it can compute the distance and time it took to complete it, and give an accurate pace for that segment. But, at the time you are running the GPS does not have a finish point to base the distance on, so it guesses how fast you are moving based on its sample points.  GPS is not a constant movement measurement device, it takes points and then measures between them to get distance and time. And, this complicated by the fact that the GPS is not on the tracker, but on the phone and connected to the tracker via Bluetooth.

[Tom168]

Actually I think I figured out why the current pace is so inaccurate and it should be an easy software fix for developers. I tested the run feature on the Charge 2 again but this time I was actually on a bike. The average pace, current pace and distance was wildly inaccurate. Fitbit reported average pace of 30:17 and distance of 0.12 miles while the Runtastic app reported 6:30 min/mile pace and 0.58 miles. Also the Charge 2 was displaying a current pace of zero or 30:00+ min/mile. I think the issue is that the Charge 2 doesn’t actually use the connected GPS while tracking runs to calculate current pace but uses wrist movement and stride length instead. This would explain why it was so inaccurate when my wrist was stationary on a bike but not as bad when I’m actually running. It could be an easy fix if they just made the running feature use the connected GPS because when I track bike rides with the Charge 2 the current speed shown the on the display is at least somewhat accurate.

[USAF-Larry]

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@Tom168 wrote:

 I think the issue is that the Charge 2 doesn’t actually use the connected GPS while tracking runs to calculate current pace but uses wrist movement and stride length instead.

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As a systems engineer, I think it may be a little more complicated than that, @Tom168. Since Fitibit said they use the GPS calculations to update the stride length, I think that rather than using live GPS readings like they do for a bike ride, the use GPS points for walking & running, and then use the time between those 2 points as well as the number of steps to arrive at the stride length. This, of course, has to be after the fact processing, rather than real-time - it would have to wait until the 2 points are established to calculate the time, distance, and steps to arrive at a stride length. Of course, that is just a best guess on my part...

[bbarrera]

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@USAF-Larry wrote:

After the run is completed it can compute the distance and time it took to complete it, and give an accurate pace for that segment. But, at the time you are running the GPS does not have a finish point to base the distance on, so it guesses how fast you are moving based on its sample points.

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Huh?

When using Connected GPS the Charge 2 has all the data required to calculate pace/mph in realtime. I'm using a different "connected GPS" on a well-known smartwatch and it has no trouble providing an accuate pace and MPH during walks, runs, and bike rides.

Pace was working on Blaze last time I checked... 

[mcats]

Still getting a .1 distance on a cycle ride that shows 8miles from my cyclemetere app. iOS 10.0.2 iPhone 6SPlus, Fitbit app ver 22.44.12.

The map is accurate, shows the full route. The reported distance is clearly incorrect.

tnx 

[bobby2478]

The latest software update makes mention of improvements for connected GPS and multisport modes. Did this also fix the known issues with connected GPS and walk, run, etc being inaccurate?

[USAF-Larry]

The accuracy of the Charge 2 with Connected GPS seems to be a variable thing, @bobby2478.  I did another test on my Charge 2 yesterday, and it turned out accurate within .08 mile over a 5-mile walk (You can see that test Here). Meanwhile others have experienced distances way off.  I think a lot of people are experiencing problems with Bluetooth disconnecting between the Charge 2 and the phone, while eliminates GPS measurements during that time.  I have not experienced that problem with my Android phone since I disabled the Battery Optimization feature.

[Tom168]

No, it's still inaccurate. I've wasted too much time comparing the data with other trackers and have come to the conclusion that the Charge 2 just doesn't work as an excercise tracker. It's decent for general fitness tracking but horrible for tracking actual excercise. 

[USAF-Larry]

This afternoon, I took a short bike ride just to check out a bike I have been rebuilding for a friend. I rode it from town to home, a distance of 6 miles. I used the Charge 2 with Connected GPS to track the ride, and it measured it a 5.96 miles, a difference of .04 miles from the expected distance. Neither the GPS nor the Bluetooth disconnected during the ride according to the map.

[Petr_Pavlik]

Hi, I ran a trail running race this Saturday and used Charge 2 to record the activity. Used also connected GPS. However, the Fitbit calculated the distance of 11,36 km. The race was 12 km long and it took place in pretty mountainous terrain so I thought the difference might be attributed to the altitude profile and may be dense forest. Nevertheless, I tried what one of the guys here suggested. I exported GPX file from Strava, and uploaded it again. Suddenly, the distance was much more accurate - 11,9 km. Question is, why is the distance so inaccurate, while the tracker has all the data available to calculate it properly. Especially, if you run competitively, it is very annoying, that you cannot rely on the displayed results. Average pace is off, and so will be also the cardio fitness score.

[smj34]

I wanted to update my steps. Previously I reported my Charge 2 undercounted 2,000 steps from what my Charge HR always reports (4,500 step walk). That was pushing a dog stroller but the HR, my One, Flex, and iPhone are always close. I restarted and forgot about the issue. There have been a few firmware updates as well. Today I wore a Charge 2 and Charge HR on my 2 wrists. This time I had just a 136 step difference on the 4500 step walk. That's insignificant as a number and percentage. I'm happy with these results and have decided to keep it. Happy owner of Ultra (retired), One, Flex, Charge HR, Alta, and Charge 2.

[USAF-Larry]

That's great to hear, @smj34!  That is consistent with what I have been seeing with mine as well.  Keep on Stepping!

[CallMeKar]

I, too, have marked differences in distance between my FitBit Charge 2 and MapMyRun.  I've updated to the current firmware and restarted my device; still, when correctly synced with the GPS on my phone, FitBit's mileage is noticeably less (4.8 miles vs 5.6).  Step count is innacurate too even though I've corrected my stride length. In addition, distance doesn't match when walking alongside my son who's wearing a Charge HR. Either this issue hasn't been "solved" or my device needs replacing. Help!

[katanel]

Hi guys,

Juat read all posts here because I wanted to know how accurete is Fibit Charge 2 while walking/running.

As I well understood from here the Charge 2 isn't using the GPS connected while calculating walk distance...only if I record a Walk activity right? If yes the calculations are way off:

Example:

- My stride is calculated at 72cm by Fitbit automatically (I'm 1.74m tall)

- I've recorded a Walk activity (GPS connected) having 610m and Fibit has count 698 steps -> stride = 83cm? Another activity of walk for 570m and stepts counted were 632 -> stride = 90cm?

What's wrong?

From my manual measurements the walking stride should be around 63-64cm.

I've the latest firmware update but dind't reset the tracker.