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.

[majbugman]

Thanks for posting that @Kobalto.  I'll try starting the activity on the app instead of the watch on my ride home.

(Edited to add)

Oh wait.  It seems I cannot start a biking activity from the app only the device. The only choices on the app are run, walk, or hike.  So I have to start the bike activity from the device.  <Sigh>.  So I can start the bike activity from the watch and get bad GPS or just use Strava and get accurate distance but with no heart rate, because the charge 2 does not communicate HR directly to Strava LIKE MY BASIS PEAK USED TO!  

[hawkeye1952]

Here a good one. Just read a article and fitbit is reporting a data breach.

[Kobalto]

Hi @majbugman. Yes, it seems you can't start a bike excercise with the app. And on top of that, now there is an issue with the tracking of the app since feb 22. Multiple users are reporting that in other forums. Just check my today's run, tracked using the app:

 It was 20k, and all the splits are showing that, but the excercise summary on top shows 15.25k. And the pace is 6'50", although when I finished the run the fitbit was showing 5'11". 

[hawkeye1952]

Here how bad this connected GPS is. Today I left it on by accident. I went into town to a dog expo. It did not even track my route I took by car. It show me walking thru cornfields across hwys , over homes. You name it. It track only 1.41 miles. distance by the way the crow fly's 15 miles. This is unbeliveable

[Colinm39]

@hawkeye1952I'm have been testing the Blaze for Connected GPS issues and a couple of tests I did was just in the car to test the signal and route. It tracked a perfect route straight for 2.3 kms to the Supermarket. Because there was no arm movement while driving, it only credited me with the walking  to the car and from the car at the carpark. That would explain some of your tracking.

I'm fortunate at home, I'm only line of sight 250 metres from a 4GX tower, my phone is an Android Sony on V7. My old phone Sony phone Android V5 last year was causing me to jump over buildings and visit backyards, useless. So I used the Surge then.  Most of my walks are within 1 km of that tower and fairly flat terrain in suburbia.

My current phone has no issues with any of my Fitbits and I have not had any of the errors as reported on Android and me last year and I was getting frustrated. I have had the Blaze since Feb 2016. The phone since Sep 2016 and it isn't on the approved list by Fitbit.

I must presume that same logic is in the Charge HR 2

Now waiting for the Blaze upgrades for your V02Max etc..

[Annabel_b]

Hi Kobalto

I have been using the app with reasonable accuracy up until a few days ago. This morning it tracked a 16.07km run as 12.83km. I could live with the Connected GPS problems while the app was working but wrecking the app has made the Charge 2 virtually useless. This is going from bad to worse 😞

[hawkeye1952]

I took my morning walk today. I start the fitbit app and used the tracking feature in it. Then I start me Endomondo app. After I finish my walk. The walk is usually 1.75. The Add to dictionary had it at 1.75, Fitbit app had it as 1.60 miles. The one thing that I have seen time after time. The further the walk, run whatever. The more the fitbit is off.

[hawkeye1952]

It sure did not fix the problem. If anything it made it worst.

[majbugman]

I want my Basis Peak back. I don't care if it "burned" a couple of people.   

[Glennbest]

Hi Maj,

The charge 2 uses the phone's gps signal to calculate the pace and distance using it's own circuitry, as the app is correct most of the time (except yesterday when it recorded an 18.8 km run as 14.65). There is a discrepancy introduced when using the connected gps feature.

[majbugman]

Interesting.  Wish they would let me track a bike ride from the app.  Oh, well.  Looks like I'll be using Strava until they fix the issue. If fitbit only fed HR data directly to Strava it would be good enough. 

[SunsetRunner]

My dashboard is showing the same for a 9 miles walk with 9 miles split but a total distance of only 5 miles - what I notice is if I export the tcx file and upload into mapmyrun, it does shows the correct distace of 9 miles - this was a GPS tracked walk where the map path is correct. Not sure what is happening but I can that I am not the only one here.

[Glennbest]

Hi Maj,

Fitbit do send hr data to strava. Maybe check your sync settings.

[majbugman]

HI Glenn,

  It kind of does. If I track an exercise on fitbit the activity goes from the fitbit cloud to the Strava cloud. And vice versa.  However, if I get inaccurate GPS via fitbit, that inaccurate data goes to Strava. If i use Strava to track a ride, it will send the positional data to fitbit but Strava will not capture my HR.  What I would like is for the fitbit device to send HR data directly to my Strava app.  

[Javaid]

I am having exactly the same problem for the last ten days. The walk is tracked accurately on GPS and also as time & distance splits, BUT the summary gives much reduced distance & speed. Please help. IMG_2160.PNG 0 Vote
Walk summary is wrong, whereas the split times & distances are correct
Walk summary is wrong, whereas the split times & distances are correct

0 Votes

[Javaid]

NOT SOLVED

[Javaid]

I am having exactly the same problem for the last ten days. The walk is tracked accurately on GPS and also as time & distance splits, BUT the summary gives much reduced distance & speed. Please help. IMG_2160.PNG 0 Vote
Walk summary is wrong, whereas the split times & distances are correct
Walk summary is wrong, whereas the split times & distances are correct

0 Votes

[Rollerskier]

For your information I came upon this program to calculate distance between 2 points represented by longitude and latitude values. You dont have to usume any values based where you are situated on the globe.  Its based on the mean earth radius = 6,371km.

This uses the ‘haversine’ formula to calculate the great-circle distance between two points – that is, the shortest distance over the earth’s surface – giving an ‘as-the-crow-flies’ distance between the points (ignoring any hills they fly over, of course!).

Haversine formula: a = sin²(Δφ/2) + cos φ1 ⋅ cos φ2 ⋅ sin²(Δλ/2)
c = 2 ⋅ atan2( √a, √(1−a) )
d = R ⋅ c
where φ is latitude, λ is longitude, R is earth’s radius (mean radius = 6,371km);
note that angles need to be in radians to pass to trig functions!

You will find it on this link if you like to test it out yourself.

http://www.movable-type.co.uk/scripts/latlong.html
It even displace the distance on the Google maps.

I tested it on one location with find my position in the Apple app Maps.

Took 10 readings on the same location by walking away about 100m and approaching again 10 times.  Compared this with the coordinates picked from the map itself.

Test                           Latitude      Longitude   Deviations ( in various directions )

Based on the map:   59,9422     10,6146       0,00 m
My location 1            59,9423     10,6145     12,44 m
My location 2            59,9422     10,6145       5,57 m
My location 3            59,9422     10,6145       5,57 m
My location 4            59,9423     10,6146     11,12 m
My location 5            59,9422     10,6146       0,00 m
My location 6            59,9423     10,6145      12,44 m
My location 7            59,9422     10,6146        0,00 m
My location 8            59,9423     10,6146      11,12 m
My location 9            59,9422     10,6147        5,57 m
My location 10          59,9422     10,6147        5,57 m

This is measured under the best condition with holding the phone in my hand under blue sky.

[Javaid]

I have the latest SW/firmware for my Charge 2, but the problem is NOT solved, the snapshot below shows the split distances correctly, BUT the summary is very WRONG. 

[Kobalto]

@Rollerskier, so in your location, according to your numbers, 1 deg of longitud = 55,700 m, and 1 deg of lat = 111,200 m.

In my location, for latitude is the same (its the same in all the world...), but for longitude, 1 deg = 92,800 m.

Here is the excel I use for my calculations, is ready for adding any TCX file. Just open the TCX file with Excel and copy/paste the table with the data replacing the old ones. It important to replace the yellow cell with the distance between long degrees.

It would be good to know if someone from a different location has simmilar results, with a discrepancy with the GPS pace, but a small error with GPS 2. That number could be calculated with the link sent by @Rollerskier  

https://1drv.ms/x/s!AkHt0GIzDqM5hbwl8Mlw7Bs8yYeQpg