Ionic GPS Inaccuracies

[MP4]

Hi, 

I'm a new Fitbit user, bought an Ionic on Monday and I'm having some issues with the GPS. Went on a couple of runs (at a track) and the gps seemed to be completely out both on the distance travelled and pace per kilometre.

I'm a long time strava user so yesterday I went for a run with both the Fitbit Ionic going and the strava on my iPhone running at the same time. Here are the results:

Strava - 7.9km   @ 4:15/km

Fitbit - 7.2km     @ 4:34/km

The difference of 0.7km is quite big and the difference in pace is also worrying. I waited till both had connected to gps before starting the run and I run in London where gps signal should be good. 

Is my Fitbit Ionic GPS not working correctly? Any help/advice would be appreciated. 

Thanks

Matt

Moderator Edit: Updated Subject for Clarity

[bbarrera]

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@bmw54 wrote:

I'm almost certain that Ionic is measuring distance and pace based on some step-count/stride-length calculation. It doesn't appear to be using information collected via GPS. 

In almost all cases the GPS mapping downloaded to my phone looks spot-on accurate. So GPS is working correct. During training runs the mile-cues and pace look reasonable.

...

...

But when I pick up my pace and stride while racing, Ionic's distance becomes understated and the pace displayed is overstated. Yet it's course mapping - as I said above - is very close to perfect. 

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@bmw54 are you allowing Ionic to auto-detect your runs? Or manually starting run using Exercise mode?

The reason I ask is that, at least on the Blaze, if you record a GPS Walk in Exercise mode then Fitbit ignores GPS for distance and uses stride * step to estimate distance. The GPS is only used for mapping in this mode.

Given that, there are several plausible explanations for the odd behavior you are seeing:

- Ionic in auto-detected Running mode will only use GPS for mapping, and stride to estimate distance

- if you manually start Run mode, and wait for satellite acquisition before starting run, perhaps the Ionic temporarily loses satellite lock and reverts entire run to using stride for distance estimation

- some weird software bug is being triggered on your manually tracked runs, resulting in stride for distance estimation

Hope that helps.

[SunsetRunner]

To add to what @bbarrera mentioned, also verify that your setting (via the website) are correct. They should be default to all "On" and checked, but who knows...

[MattFitbit]

Hi everyone! 

Again, I just wanted to thank you all for providing such detailed feedback on your experiences using GPS on Ionic. 

I have been in touch with our engineering team and they have advised that your reports have helped them to take a deeper dive into what might be causing these inaccuracies. 

We are currently working on a fix that we are hoping to have released in the near future. However, I don't have a specific timeline but I will be sure to keep you informed once I hear confirmed dates.

To help improve GPS accuracy in the meantime, I recommend following each of the tips which were posted, here. 

If you have any questions, let me know! 

[bmw54]

Zen (and others): thanks for your suggestions!

First, I have GPS 'on' and don't use auto-detect. I manually start the exercise after GPS is detected and the starting gun fires.

I examined the GPS coordinates so I know that it's working. They added up to 4.53 miles on a sanctioned 5-mile course. This percentage is consistently understated with the 8 other races I've participated in since strapping on the Ionic.

Here's the 'exercise' from the dashboard. There are a couple cut corners but I can't see how .47 miles could have been lost:

[shipo]

@bmw54, interesting; I don't think I've ever seen an accurate track on a map and yet had the total distance vary by more than a tenth of a mile over the course of a 10 mile run.  Regarding cut corners, my Surge was notorious for doing that and so too was my Garmin Forerunner (but to a lesser degree than the Surge); my Ionic plots corners and curves dead-on accurately roughly 29 times out of 30, and when it screws up, so far at least, it has always been on a heavily wooded trail run.

[SunsetRunner]

@bmw54 Wow, yeah, that is strange. Clearly ~0.5 mi short on what traces as a 5 mile route. Certainly is something wonky with your GPS.

I have never seen anything like that with mine, and I often run a crazy, loopy route with lots of turns and cutbacks. 

[RonanB]

Good work Matt; sounds like it might be worth holding out for the fix?

Separate question: I've run twice with the watch listening to music via bloothtooth Bose earphones and had no issues. Last day I went out, however, the connection was extremely crackly to the point there was no point listening. I reset the earphones, paired and unpaired but the near constant crackly sound remained both devices were fully charged). Note: it only crackled whilst running not when stationary. Do I need to wear on my right arm or something? Any tips from you or that fabulous bunch of engineers would be great.

Crackling and slightly geographically displaced regards,

Ronan

[Tunah85]

@shipo My maps are reasonably accurate, I think its the interpretation of the raw GPS data that is off.  On my most recent interval run part of my sprint interval (run at 3:55/km pace) randomly dropped to 6:23, then bounced back up... It was down there long enough it to be displayed in the post-run graph.  When I go look at that section of the map nothing jumps out... The raw map data seems good.

It is important to note that the pace didn't fall off during the start of my sprint, but during the middle.

[bmw54]

To persist on this subject, after a 10.4 training run yesterday that Iconic's GPS route tracked accurately and measured distance/pace correctly I'm left wondering what it is about racing that challenges Fitbit so badly.

Here's the race course and total miles (4.53 miles) as measured by the Iconic (last Thursday):

And here's the same course as measured on the web (5.03 miles... I may have overshot the finish line a bit):

[bmw54]

sorry, here are the maps:

Iconic:

web:

[shipo]

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@bmw54 wrote:

To persist on this subject, after a 10.4 training run yesterday that Iconic's GPS route tracked accurately and measured distance/pace correctly I'm left wondering what it is about racing that challenges Fitbit so badly.

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I've been wondering the same exact thing about your Ionic.  Maybe mine always works, regardless of whether I'm racing or not, because I'm old and slow.  🙂

[bbarrera]

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@bmw54 wrote:

To persist on this subject, after a 10.4 training run yesterday that Iconic's GPS route tracked accurately and measured distance/pace correctly I'm left wondering what it is about racing that challenges Fitbit so badly.

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@bmw54 It seems pretty clear to me, you have a training pace and a running pace. For some unknown reason (existence of bug acknowledged by Fitbit in this thread), Fitbit is using your training stride to estimate distance and that means your racing results are wrong.

[shipo]

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@bbarrera wrote:

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@bmw54 wrote:

To persist on this subject, after a 10.4 training run yesterday that Iconic's GPS route tracked accurately and measured distance/pace correctly I'm left wondering what it is about racing that challenges Fitbit so badly.

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@bmw54 It seems pretty clear to me, you have a training pace and a running pace. For some unknown reason (existence of bug acknowledged by Fitbit in this thread), Fitbit is using your training stride to estimate distance and that means your racing results are wrong.

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Hmmm, that doesn't make any sense; I train in the nine to ten minute per mile range but typically race in the mid to high seven minute per mile range.  My Ionic and Surge both track flawlessly.

[SunsetRunner]

It is the **ahem**ty way fitbit track pace and run data. If you have GPS, should ONLY be GPS. They are unlikely to change this unforuntately.

[bbarrera]

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@shipo wrote:

Hmmm, that doesn't make any sense; I train in the nine to ten minute per mile range but typically

race in the mid to high seven minute per mile range.  My Ionic and Surge both track flawlessly.

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@shipo

1. Fitbit acknowledges a bug

2. You clearly aren't experiencing the bug

3. Other users are experiencing the bug

ok, I'll modify what I said:

@bmw54 It seems pretty clear to me. For some unknown reason, Fitbit distance calculation is incorrect when you run a race. They have acknowledged the existence of a bug that might be the root cause of your problem. Stay tuned.

[bhwolf]

Did my first mtn bike ride with the ionic today, largely wooded so I know it's a challenge for GPS.  Still, coming from the Microsoft Band 2, it's definitely less accurate.  It picks up some of the curves ok (understanding it's wooded and all), but it would be great if there was a higher frequency or something as an option even if it meant higher battery drain.  There was one part in particular where it completely seemed to lose me for about a mile, and drew a straight line connecting as you can see in the image below.  I've drawn green on the map where I should have been (roughly).  So, meh first experience, hoping it gets better.

(Trying to figure out how to attach a local image, will upload when I figure it out.)

[shipo]

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@ngmiler05 wrote:

It is the **ahem**ty way fitbit track pace and run data. If you have GPS, should ONLY be GPS. They are unlikely to change this unforuntately.

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I think you're misunderstanding how the Ionic works; when in GPS mode, the ONLY means of measuring distance and pace is via GPS.

[bbarrera]

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@shipo wrote:

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I think you're misunderstanding how the Ionic works; when in GPS mode, the ONLY means of measuring distance and pace is via GPS.

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The Ionic may not be in GPS mode for the entire run/walk/ride... What happens if mid-run, the Ionic temporarily loses GPS lock and then reacquires? Or doesn't initially have GPS lock?

[SunsetRunner]

@bbarrera When I lose gps lock, which had only happened twice, I see a discontinuity in the map track. 

As for no initial lock, well then you're not in gps mode are you? Then of course it uses stride length.

I'd like to know where this "training" stride length you mentioned is located. I can't find any mention of it. 

[bbarrera]

@SunsetRunner the more interesting questions for a mid-run loss of GPS lock are "what happens to pace display on Ionic?" and "how does that impact distance calculated?"

Only two strides, walk and run. My earlier point regarding two strides.... suppose there is a rarely seen bug where Ionic mistakenly uses stride to calculate distance during a GPS run. If your Fitbit run stride is configured as your normal training stride, and your racing stride is longer, then you would only notice a large distance error during races.