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DeepButi

Tired of my etrex touch 25

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After years of using without the slightest problem a Garmin Dakota, it died some months ago and I replaced it with an etrex touch 25.

It proved to be incredible unacurate in most circumstances. Way go and back can be easily 20 or 30 meters away in areas with good signal.

But what makes me really nervous is it's unability to understand I stopped! Today I checked carefully. Sitting down at a small mountain peak for 15 minutes it added more than 650 meters (aprox 2000 feet) to the track! A clean area, not a single cloud, no trees around me, nothing. I was watching the instant speed ... 2 or 3 km/h was a constant, even 7km/h for several time. Incredible. This of course makes any track data unusable and worthless.

Anyone uses it in a satisfactory way? Is there any setting I could change (if the instant measure was every 3sec for example, the errors should be quite lower, isn't it?) ?

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It should not do that.  Try a master reset.  If it still has problems after that, contact Garmin for a warranty replacement.

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I've experienced your problem (summits) on 3 different (warranty) OR600s and on my current OR700.  Good luck in your endeavors with Garmin.  I have never experienced the scatter on a summit with my 60cSX.  Have encountered multipath in canyons with my 60cSX, but never on a summit.

Maybe quad-helix vs patch antenna?

 

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9 hours ago, jimlarkey said:

Maybe quad-helix vs patch antenna?

 

Not likely. I'm willing to bet the problem is GLONASS. Despite having more satellites, I sometimes get a more stable position when I turn GLONASS off and only use GPS. If I had to guess, the two systems aren't entirely calibrated to one another.

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The weird wondering issue is a software problem that started around the middle of the firmwares with the Colorados.  It has nothing to do with GLONASS.  Every Garmin handheld from that point has had the same issue.  They partially fixed it, but it still shows up every now and then.

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The attached shows 6 track logs of the same hike.  You can three times where the tracklog just wandered off for no reason.  If you look at the GPS when it is happening, it show decent accuracy, but it shows you in the wrong location by hundreds of meters.  I'm sure we can find discussions here.  It started happening at some point after the Oregon 450 was released, but effected all models.  It seems to have improved as it is fairly rare, but you can see I had it happen with a 64S last year.

Capture.JPG

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My hike with an OR 700 in Soapstone Prairie shown below clocked me at 767 mph, with a major spike of 2.7 mi.s.  Many smaller spikes also shown, crossing the CO/WY border.  Never encountered this with my 60cSX.  Doubt that GLONASS is the culprit, since many tech papers report increased accuracy with GPS+GLONASS, although not rec grade receivers.

 

 

 

 

2018-02-04_123102.jpg

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I've never had a spike quite that big. When I do get track points that are way off, I'm usually deep in a canyon where signal can bounce off the canyon walls, or on the side of a mountain in deep forest. The "wandering" I'm talking about are the birdsnest of points that accumulate when stopped. Or the time it takes to get a good coordinate reading with waypoint averaging when hiding a geocache. My position seems to more stable when I turn GLONASS off. I use an Oregon 600.

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This is the scatter with my 3rd OR 600 on the summit of Golgotha (11,200'), beautiful day, clear view of horizon, lots of mosquitoes......the lower left loop with the orange is all scatter.  A 7.8 mile spike!  When I finally bailed on the 600, the REI manager said he had many other customers report similar when I showed him this image.  Thought I'd move onto the 700 since they changed the patch location on the circuit board, but not impressed.  Use my 60cSX with worn buttons, for important navigation.

Interesting thread.

 

2018-02-04_130706.jpg

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While it's a bit fiddly, you can clean up some of those noisy tracks in GPSBabel.

Garmin hides the DOP information that would almost certainly identify the nonsense points and let you toss them with the DOP filter ala https://www.gpsbabel.org/htmldoc-development/filter_discard.html Bad data points like the upper right corner of the first map by jimlarkey would almost certainly get cleaned by those.

The distance option in the track filter https://www.gpsbabel.org/htmldoc-development/filter_track.html could be used to break the track in the post above this one into two distinct tracks. Choose a threshold so that the straight lines get busted into separate tracks.

The simplify filter https://www.gpsbabel.org/htmldoc-development/filter_simplify.html can be used to reduce the sheer number of points in a track. Because it removes points that change the overall shape of the track the least (unfortunately, thus favoring that "zinger" in Soapstone; arrange to remove those first) it can be helpful to removing clutter at trail heads, resting points for cyclists/hikers/campers, stop signs and such.

While a GUI with a "make this track less terrible" that can figure out what combination of the above - esp. in light of Garmins that insist on recording made up data and not telling you WHAT data is low quality - would be awesome (please send me the code for that if you implement it...) I'm aware of no such tool. If you have valuable tracks that are worth cleaning up and are prepared to spend some time fiddling with it, the raw tools are in GPSBabel.
 

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