Blaze Distance accuracy

[HannahNB]

Hi there 🙂 I have been using my Blaze in training for a running race I completed last weekend. I pair my Blaze with my phone and use the GPS tracking to measure my distance. I run outside, on the road, and always have connectivity with the internet (I stream music and it plays continuously). I clean the Blaze regularly and wear it tight (but not too tight) on my dominant wrist (and have the settings noting that it is on my dominant hand)

My race was last weekend and the official race distance was 14km. I again tracked my run using GPS via my phone, and my Blaze tracked my distance as 16.9km - almost 3km longer than the official course distance. I understand there is likely to be some variation in my distance given the zigzag nature of road running, and that I may have been slightly back from the start line when I started running, but a 3km difference seems like a huge discrepancy.

What could have caused this? Are all my runs inaccurate? This GPS tracking function totally useless?

Thanks in advance!

[Giampi71]

Hello HannahNB and welcome to the forum.

The problem you are speaking about is well known and here you can find one of the many topics about the subject

https://community.fitbit.com/t5/Blaze/Blaze-Distance-Incorrect/m-p/1888814#M50823

In my case I had great results deactivating the run cues and letting the GPS be connected for 5-10 mins before starting the session but it seems not anyone is able to reproduce the behaviour.

This morning I received the new update and I will try it over the weekend. 

[Colinm39]

@HannahNBThere isn't much being posted here, but in the Charge HR 2 Forum there are Fitbbitters showing us there is a distance issue when walking/running in an East/West (E/W) direction. After my testing the Blaze, it is no different to the Charge with Connected GPS.  Perfect on MapMyRun and Polar Beat.

I have proven that, comparing my Surge and the Blaze in the Southern Hemisphere (Australia)  It is so obvious that the Blaze has my pace 2 min/km faster than the Surge.  Both track the maps perfectly.

The error is a mathematical gain of about 12" or 30cm/second in the E/W direction.

It would be difficult to break your run up, but I planned specific E/W and North/South (N/S) routes and the N/S was perfect and matched the Surge.  All of my triangular routes around our local park always had extra distance. Any walk around our neighborhood which always has N/S streets and E/W courts gives extra distance.

Were there any jagged deviations which others are reporting because of the Bluetooth disconnecting from the phone.

There is some confusion how your stride length is handled in Connected GPS.

[Riekopo]

Wow it sounds like Fitbit better hire Colinm39 to fix their **ahem**.

[Colinm39]

@Riekopo We are trying to gather pointers for Fitbit and keep them assessing the Connected GPS.  There has never been any Moderator posting that our testing is inadequate. Especially when you look at the Charge HR Forum. See this link

We just want the Blaze to give us the results that it was designed for and reading some other posts the Moderators are passing the posts onto the Engineers..

I'm no expert, a retired engineer who enjoys his baselines and compares my Fitbit armoury..

Like me, you have been with Fitbit for awhile and based on past performance Fitbit will get there.

It's always difficult for technology driven companies to get the balance between new sales and support.. I'm patient...

[HannahNB]

Thanks so much for this information Colin. I'm Southern Hemisphere also (NZ) and the run was almost directly west/east across the city, so this makes a lot of sense with the error you have found! The route itself was tracked perfectly with no drops/lags in the tracking, it was just the wrong distance and km/hr data.

I'll try your suggested fix and see how I go, but also wait hopefully for a fix to the tracking data. 

Thanks again, really appreciate the details! Hannah 🙂

[Colinm39]

@HannahNBI answered @Riekopo earlier and decided to stop at our local swimming centre which has some nice ovals with square walk path perimeters.  I was using the Blaze Actual Pace as a display when I tapped the screen to watch the change between directions. It wasn't immediate, but gained.. 

The image below shows the consistency of the steps, and the Pace shows the extra pace in East/West direction.

Ironically the steps as recorded by the Connected GPS = the Fitbit One.  Because the GPS is down to the second I can only use actual minutes using the Activity Record to show the steps/minute (spm) bar chart.

Notice the drop off of steps from the Blaze and the Pace was faster, now whether that was the lack of recording, because like many I have a drop off when I walk domestically. As you can see here the Blaze is down by 2-3% and fell right away at the last 2 minutes. When I walk at Exercise to Brisk walking pace the Blaze and the One are within 0.5%.

There weren't any Bluetooth dropouts and the Phone Connect was immediate.

[hatzinikolaou]

@Colinm39hello Colin and @HannahNB! Thank you for this very informative post. I have discovered that using my blaze with mobile GPS the run that I thought was 18 km was in fact only 15km according to the map... and my pace at least 2 minutes per kilometre faster than I had been running. I too am in New Zealand. A question for you Colin, have you tried the Ionic? Does it have the same problem? I wonder if the built-in GPS solves this issue. As I am training for a half-marathon at the end of this month and sadly all my stats are right off for the past few months so I think I might make the move to the Ionic if it looks more likely to be accurate. Thanks in advance, John

[Colinm39]

@hatzinikolaou I have only tried a short test because it took so long for the Ionic to find the Satellite as did my Surge. I will also use MapMyRun.

But a plus was the tracking I did was accurate and no wobbles.

Fortunately my streets and courts go E/W. and N/S and it has already been posted that App V2.58 hasn't fixed your problem.

[Colinm39]

@hatzinikolaou  I just did a small test using MapMyRun and the Ionic.... At the end I compared it to Google Earth and only 4m different over 511 metres and MapMyRun.. My court goes E/W and the stretch is 90m straight with a 5m incline which you can see on the graphs.  Also MapMyRun which had very brief pauses.. Satellite dropout. Over the last few weeks I had been blaming my phone using the Blaze and the App but the same thing happened on Ionic which confirmed it was satellite and not my phone.

Pace was consistent with the elapsed time 4.7 to 5km/hr and it took me about 25m to have the satellite connect, even though my GPS Status App showed immediate connection. When it connected I pushed the button and then finished when I hit 0.5km, hence the parting of the start and stop points.

The plotting of the graph is accurate but skewed slightly to the left.

I will use the surge next time and do the same thing.

If I walk at night my wife's happy that I just walk up and down the court in the dark.. I get the benefit of the incline and then the "rest" walking down. Sort of HiiT....if I push it harder..

Thanks for posting, that egged me on to do something....

[hatzinikolaou]

Thanks @Colinm39 that’s odd that the satellite fix is taking so long! How weird - I wonder if perhaps our antipodean location is not assisting things. Very interesting metrics / stats that you have come up with! Thanks for sharing!

I think it’s fair to assume that if my blaze is highly inaccurate using phone GPS (whether due to the direction of my routes - often north - South and vice versa) or due t some other issue, there really is no point in me going out and buying an Ionic as the Fitbit software seems to be leaving us Australian and New Zealanders in a bit of a bind in terms accurate pace / distance... to say nothing of the GPS satellite fix delay.

i had wondered if built in GPS like with the Ionic or Surge might solve my problem and that my issue was somehow due to the fact the blaze is using phone GPS but I think it’s going to occur even if I get an ionic unfortunately - at least until Fitbit sorts this issue out software wise.

the bad news is I thought I’d been running nearly 20 km but it’s more like 14 now that Ive checked on other apps. Yikes! I’ll have to pick up the (real not Fitbit!) distance before the half marathon on the 27th... 

as a marathoner do you have any tips for the big day except maybe just to pace myself ? It’s my first time doing a half.

[Ronald1]

@Colinm39 wOW