General Discussion Triathlon Talk » GPS accuracy, Garmin Forerunner 305 or Runkeeper? Rss Feed  
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2010-07-27 1:07 PM

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Champion
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Subject: GPS accuracy, Garmin Forerunner 305 or Runkeeper?
There was a .37 mi discrepancy in my run this morning between the Garmin and Runkeeper on my iPhone- not a huge deal except that, well, I wanted to run 5, not 4.63.

A brief Web search = people swear on each's accuracy.

What do you say?


2010-07-27 1:12 PM
in reply to: #3007757

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Subject: RE: GPS accuracy, Garmin Forerunner 305 or Runkeeper?
I'd pick whichever was longer 

Only have the 305, but in my experience over the last 2-3 years I've had it is that it is incredibly accurate.  Perhaps one of them lost a signal at some point

Edited by ChrisM 2010-07-27 1:13 PM
2010-07-27 3:02 PM
in reply to: #3007757

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Subject: RE: GPS accuracy, Garmin Forerunner 305 or Runkeeper?
I recently did 2 runs and 2 bike rides wearing 2 separate Garmin 405's.

I expected them to be within 20-30 feet of each other, but I was way wrong.  Two identical units were at times that close, but were just as often 150 feet apart.  Lap times (for 1 mi distances) were sometimes as close as 3 seconds, but also off as much as 12 seconds.

So- they're not quite as accurate as you'd hope.

Instantaneous pace was sometimes as close as 10 or 20 sec/mi, but just as frequently more than 1min/mi off, and sometimes 1:30 off. 

here is one pair:  This one ended up being very close in the end distance, but was pretty far off at times in the middle of the run.
http://connect.garmin.com/activity/40329858
http://connect.garmin.com/activity/40330034
2010-07-27 6:18 PM
in reply to: #3007757

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Subject: RE: GPS accuracy, Garmin Forerunner 305 or Runkeeper?
Not surprised given the margin of error for Garmin GPS's are +/- 19 feet.  
2010-07-28 12:36 PM
in reply to: #3007757

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Champion
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Subject: RE: GPS accuracy, Garmin Forerunner 305 or Runkeeper?
So today, a 1.3 mi walk around the block (as calculated by my car) had both Garmin and Runkeeper off .2- but IN EACH DIRECTION! So the answer is: NEITHER!  grumble.
2010-07-28 3:48 PM
in reply to: #3007757

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Subject: RE: GPS accuracy, Garmin Forerunner 305 or Runkeeper?

Keep in mind that the iPhone will fail over to GPS-A.  GPA-A (Also known as assisted GPS), means that if it loses sat reception it'll use cell-based triangulation.  This has a much lesser degree of accuracy.

The Garmin FR305 does not have GPS-A, and thus if you lose GPS signal...it'll stop recording data points.  Once you gain signal back (within the specified accuracy range), then it'll start plotting data points.  The distance between the last known point and the next known point is automatically computed (albeit in a straight line).

In short, the Garmin is likely to be more accurate in a sat loss situation.  In a non-sat-loss situation, they're likely to be mostly identical outside the normal GPS variation and recording interval ranges.



2010-07-29 7:23 PM
in reply to: #3010747

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Champion
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Subject: RE: GPS accuracy, Garmin Forerunner 305 or Runkeeper?
wait, neither has that GPS-A or is that a typo?

either way, you say Garmin, I'm goin' with Garmin. Thanks.
2010-07-30 2:02 PM
in reply to: #3013268

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Subject: RE: GPS accuracy, Garmin Forerunner 305 or Runkeeper?
possum - 2010-07-29 8:23 PM wait, neither has that GPS-A or is that a typo?

either way, you say Garmin, I'm goin' with Garmin. Thanks.


RK will, but Garmin's don't.  GPS-A is cell-based technology, and none of the current Garmin's have cell antennas in them.

Hope this helps!
2010-07-31 9:39 AM
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Subject: RE: GPS accuracy, Garmin Forerunner 305 or Runkeeper?
Between my wife and I, we've had just about every garmin GPS model. She is worse than I am on buying gadgetry but we get to try out a lot of stuff. We are always within a few steps of our mile mark beepers regardless of which model used. For routes that are premeasured and certified, we are always within a hundredth or two of the actual distance. Realtime pace numbers are always adjusting and are kind of iffy but overall distance seems right on to me.
2010-07-31 10:31 AM
in reply to: #3007757

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Subject: RE: GPS accuracy, Garmin Forerunner 305 or Runkeeper?
My 305 seems very accurate, however it looses satellite reception VERY easily.  Running under a grove of trees is enough to cause a loss.  I also have a handheld GPS (C60Csx) which holds a lock much better, I'd assume a better receiver chip?

Anyway, out on the open road, on the track, or open fire roads it seems pretty much nuts on.  Trail running/biking?  Not so accurate.
2010-07-31 10:36 AM
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Subject: RE: GPS accuracy, Garmin Forerunner 305 or Runkeeper?
Garmin....hands down.



2010-08-02 9:18 AM
in reply to: #3007757

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Champion
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Subject: RE: GPS accuracy, Garmin Forerunner 305 or Runkeeper?
What do trail runners use then, for most accurate results? I'm having a a lot of fun w the Garmin, love looking at all the info on Garmin Connect, but am curious what people use?
2010-08-03 8:16 AM
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Subject: RE: GPS accuracy, Garmin Forerunner 305 or Runkeeper?
I use Runkeeper and love it for a $10 app. But.....it does seem to be spotty on gps at times. On the open trails I use it's great but I found it very annoying on a recent trip. So, I'm interested in the same thing to see if a garmin would improve the data or not. To the OP let me know how you end up deciding. Thanks.
2010-08-03 8:36 AM
in reply to: #3020332

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Champion
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Subject: RE: GPS accuracy, Garmin Forerunner 305 or Runkeeper?
Out2BeALoser - 2010-08-03 8:16 AM I use Runkeeper and love it for a $10 app. But.....it does seem to be spotty on gps at times. On the open trails I use it's great but I found it very annoying on a recent trip. So, I'm interested in the same thing to see if a garmin would improve the data or not. To the OP let me know how you end up deciding. Thanks.


Weellllll, I still use both...  I am totally fascinated by the maps and the data, and it's so easy to just have RK running too. At this point, the exact distance doens't matter too much, but I am working towards longer distance trail runs, and eventually want to be able to track distance so as not to overtrain...  I am still playing with everything at Garmin Connect and haven't even begun to use the workout features on the FR305, but as an overall tool, the FR is obviously better for me- it's the tech behind the mapping/GPS that is making me wish I understood tech better!  Thanks for all the input everyone.
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General Discussion Triathlon Talk » GPS accuracy, Garmin Forerunner 305 or Runkeeper? Rss Feed