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GPS Accuracy

Former Member over 8 years ago

So it begins.

I will have mine Fenix 5 on Saturday and will start doing comparisons to an Ambit 3 Peak. I don't have an F3 to directly compare to as of now.

Anyone have an F3 and F5 to compare?

0 chimpware over 8 years ago

Has it been confirmed that the 935 doesn't have the same issues with the Stryd that you're experiencing with the fenix 5? I've been planning to pick one up soon.

As to the tracks, yours seem similar to what I've experienced – the fenix 5 is fine, but could be better...at least as compared to the 735/935.

@TimGrose has a 935 and tested with Styrd and reports no dropping of signal on the 935.

0 Former Member over 8 years ago

I just tested the F5 vs my Tomtom Outdoor. As with the F3HR, there was basically no difference in overall distance (10 mtrs over 5.46 km, with lots of hills). The splits were slightly different. Instant pace on the Garmin was actually better than the Tomtom. On the GCM map, the plot from the Tomtom is the clear winner. It shows less deviations from actual course, but I really don't care, as the distance was near perfect. Using the One Field data screen downloaded from the store, I get an amazing amount of information, without flicking from screen to screen on the watch. Overall, very happy with the watch. Battery life is amazing, GPS distance is spot on, the screen is fantastic and customisation is brilliant.

I know having a perfect map plot will be important to some users, but the overall distance accuracy is all that matters to me, so I cannot fault it.

0 Tom Shane over 8 years ago

My first testing walk. It was with my dog, so there were frequent stops, but not romping around, so the GPS didn't have to react to rapid movement changes.

It's not anything to be ecstatic about, mainly around houses and especially in the forest. On the path to the forest, there was clear sky view, the track is not exactly smooth, but quite ok.

Total distance measured on the device was quite believable (4.01 km).

Settings: GPS only + 1sec recording.

http://www.mygpsfiles.com/app/#Cs5HHka8

Tomorrow I'll be doing similar test with GLONASS on.

Also sorry, I didn't have any other device with me to test it against.

0 webvan over 8 years ago

Some quick thoughts on v2.90/GPS v4.30. They've clearly changed something as I see less wobbling and more stable pace but distance is still off compared to the FR235. Looking more closely though it looks more "choppy" a sign of more aggressive filtering I think, hence the reduced "wobbling" but the underlying problems remain with some "multipath jumps" as can be seen here where it completely lost the plot (that lap was 10 seconds faster on the F5 vs the FR235)

Garmin are clearly trying to improve performance but it seems they're working with degraded raw data and there's so much you can do in that case...

0 Tom Shane over 8 years ago

Another go, same track - now without my dog, at slightly higher pace.

Settings: GPS + GLONASS, 1sec, v.2.90

The track surely looks visually better, but the forest part, at the turning point, I'm returning on the same path, but on the record there is almost 40m side "drift". There was some tree cover, but nothing excessive. On the other hand Lumia 950 didn't do any better.

http://www.mygpsfiles.com/app/#Cu4i4NVE

All in all, I could live with it.

0 FlipStone over 8 years ago

Some quick thoughts on v2.90/GPS v4.30. They've clearly changed something as I see less wobbling and more stable pace but distance is still off compared to the FR235. Looking more closely though it looks more "choppy" a sign of more aggressive filtering I think, hence the reduced "wobbling" but the underlying problems remain with some "multipath jumps" as can be seen here where it completely lost the plot (that lap was 10 seconds faster on the F5 vs the FR235)

Garmin are clearly trying to improve performance but it seems they're working with degraded raw data and there's so much you can do in that case...

Yeah, trying to think if there's a way to improve signal...

I opened my F5 and it looks just about exactly the same as the F3HR:

https://cdn-images-1.medium.com/max/1000/1*ML1TuHedN0Gvr2LWLJp8_A.jpeg

The gps antenna seems to be top thing, the one on the right of this picture:

https://cdn-images-1.medium.com/max/1800/1*qTv0XTW0z_nmkwNWHdHA7g.jpeg

So I was thinking about looping a copper wire around the sides of the (case of the) watch with the tips either connecting the silverish (conducting?) material of the antenna or the 2 pins of the mainboard contacting the antenna.

To do that properly I'd have to disconnect the display though (should be easy, just disconnecting the connector) and before I do that I would want to have a more solid idea of what might work and what not.

I have seen a few ppl modding their phone gps with aluminium foil and copper wires as well, but don't want to just try crap at random and open my watch too often (also, testing is pretty time consuming).

For now I'll just leave it as it is and think about possible tweaks ;)

Btw, I am also a big part nerd so I actually find this fun to do as well so it's not JUST because I need to...

0 Former Member over 8 years ago

Odd how everybody seems to be getting longer tracks with their F5. Mine are substantially shorter with corners being cut all the time. Compared today with an app on my phone and was showing a 10% error (admittedly vs my iphones gps). Pace was all over the show too, so frustrating and the reason I binned my F3 a couple of years ago

0 webvan over 8 years ago

I guess it depends if you take a lot of sharp turns, I've seen the F5 come short a few times too on some laps.

@FlipStone - thanks for the teardown pics. Let us know if you can think of something but I would think (hope!) that Garmin would have had the means of doing all the possible hardware tweaking given the design constraints, although you never know of course ;-)

0 chimpware over 8 years ago

735XT vs fenix 5 Trail Run

Here is a comparison of a trail run I attempted today (bad choice of trail and got lost a few times):

http://www.mygpsfiles.com/app/#CtBUS4Ie

GPS track of the f5 is slightly worse than the 735XT, but overall distance accrual and lap distances were pretty close (out by less than 1% on overall distance). Very acceptable in these conditions.

0 Former Member over 8 years ago

Did you make a loop a the northern most point?

I often saw loops like this with my old F3 on sharp turns. I never made a loop but they were often registered.