GPS Accuracy Test: Fenix 5s vs Suunto Spartan Trainer Wrist HR

Spring is almost here in Illinois!  Thank goodness because I’ve felt like a caged tiger being housebound these past few months.  We’re starting to get some warm days and I’ve been taking advantage of them and getting back out on the trails.  With everything going on in this world, I think we all could use some time in nature away from all the news.  I know it helps me find some sanity.

With that said I did my first head-to-head GPS test of the Fenix 5s against the Suunto Spartan Trainer Wrist HR.  I’ve done plenty of test indoors in the gym with both but I hadn’t been able to compare their GPS sensors against each other.

So, I went on one of my favorite test sites near my home which is a paved bike path through some natural areas.  Parts of the trail are in open meadows and part is surrounded by tall forest which is great testing conditions, since it’s more challenging to get a good GPS signal in forests.

I didn’t get to go on a long walk since I had to get back before it started pouring.  Both watches are waterproof and I wasn’t worried about them or me getting a little wet but my camera isn’t waterproof.  Some of the video I took will be included in my final comparison video that’s in the works but for today you’ll get a sneak peek at the results.

Update: Click here for the a full comparison article of the Fenix 5s and Suunto Spartan Trainer WHR.

My main interest for this first test, again, was the GPS performance of both.  I did pay attention to the heart rate readings of both watches but I wasn’t wearing a chest HR strap to compare against but I’ll be doing that in the future.

This first map is from Movescount, which is Suunto’s website.  This is where you go to view your workout history, create routes, import routes,  etc.  My walk began where the arrow is.  Then I walked over a couple of bridges and then turned back a little past the second bridge.   I then walked past where I had started and turned back after about a third of mile to return to the starting point again. Does that even make any sense?  Probably not but that is why there are two lines going both directions.

And here is the map from Garmin Connect.  As you can see both maps are very similar.

And here are the satellite views for both beginning with Suunto.  Looking at the satellite view can be more telling of how accurate the estimated paths are.

Something that I found to be very interesting is that both watches GPS sensors behaved almost exactly the same.  They were equally as accurate in some areas along the trail and off by about the same distance in other areas.  Both of them struggled when I got into the trees.

Here for the Suunto it looks like I did a rain dance right where those squiggly green lines are before I crossed the bridge.

The Fenix 5s shows the same results (below).  Also, if you look at the distance between both lines for when I turned back on the path, they both produced almost the same exact results.  I had stuck to the path but both showed that I had walked through the trees.

My theory is to why those squiggly lines are there is that I had stopped at that spot for a few minutes to shoot some video, so both watches were trying to determine where I was as I was standing still.

Below is about where I stopped. You can also see the size of the trees that surround the path.  It’ll be interesting to see how a full leafy canopy affects the GPS accuracy of both watches.

If I go back and look at the results of the rest of my walk, they both did very well in tracking me in more open areas but struggled a little when I was in the dense forest.

It’s important to point out that I was using both GPS and GLONASS on the Fenix 5s since it has access to both.  The Spartan Trainer WHR just has GPS but I did have “best” selected for GPS accuracy.

As far as the distance estimate, the Suunto estimated that I had walked 1.14 miles while the Fenix 5s estimated 1.20 miles.  I also had MapMyHike running on my phone and it estimated 1.26 miles.  Which one is more right?  It’s hard to say but next time I am going to turn off auto-pause on the Spartan Trainer WHR because I think it might have skewed the distance estimate some.

Overall, I’m happy with both and surprised at how they behaved almost identically as far as GPS goes.  I’ll be doing this test again with auto-pause turned off on the Suunto and I’ll be wearing a chest HRM to test HR accuracy.  Hey, it’s a good excuse to get outdoors.  Not that I really need an excuse but it’s still fun, even if I look odd carrying video equipment and talking to myself while recording these reviews in public.  No one looked at me funny except the deer but then they always look at me like I’m insane.  They’re probably right.  This world will do that to you.

>>View the Fenix 5s on Amazon: http://amzn.to/2sInQbp

>>View the Suunto Spartan Trainer Wrist HR on Amazon: http://amzn.to/2ENBGxK