Poor GNSS accuracy? [Bug 8]

[GPSrChive]

In fact it depends on the parameters of the track recording, ...., it is necessary to configure the two 67 and Epix in the same way otherwise the comparison is distorted.

Agreed.

Many watches have either 'Smart' or 'Once per Second', so the best comparison comes from setting both the watch and handheld to one track point per second.

[neilwoody]

I have used my 67 for about a month now and am very happy with it. In my opinion, the battery life, screen sharpness and positional accuracy are all excellent. I use ExpertGPS software to plan my off-trail routes and manage waypoints and tracks. I use Garmin Express or Garmin Connect for firmware updates and EPO/CPE updates. I evaluated the positional accuracy using the hiking trails and roads on the latest USGS 7.5 maps (uploaded using the Custom Maps feature) and it is spot-on. Using the GNSS and multiband settings, I achieve a steady accuracy of 6 feet, more than enough for off-trail wilderness navigation. I have track recording set at one point per second.

[gpsjorgen]

I don't know if that's the reason, but the 67 is definitely less accurate than the 66sr. All my tests prove it.

Nail, I am very interested in your experience with the 67 (and with respect to the 66sr). I recently bought one and I expect it to be at least as good as my Fenix 7 and Edge 1040. It often is, but it sometimes goes berzerk.
See my report on the Garmin forum

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Maybe you can send me some information on your testing in a PM?

[Nail]

Nail, I am very interested in your experience with the 67 (and with respect to the 66sr). I recently bought...

Thank you for your interest in my tests.
I still have both devices, although your post motivated me to get rid of one. I am not comparing them anymore, because if I did, it would probably not look good from the perspective of my mental balance . In some details, the 66sr is better, especially in the track recording, it is more precise. More precise, i.e. the GPS track changes directions quickly according to your movement, and the GPSMAP67 smoothes the line more.
I did the tests by walking the same straight line, at different times of day (taking the dogs for a walk) and when I compared the lines that overlapped many times, it turned out that the 66sr painted a wider strip compared to the 67. This means that the 67 is more accurate in positioning.
Sometimes the 67 restarts more often, especially when I use the search engine. I also do not like the new menu with map layers, I never know if the maps are on or off. The screen zoom is also one step lower than the 66sr, I often want to zoom in to see some detail but I can't. On the plus side, the low battery consumption and the fast refresh rate.

I'm sticking with the GPSMAP67 as it's the model that will be updated more often, which I hope will improve performance.

As a curiosity I will add (maybe someone will be interested) that when I put GPSMAP67 outside with a USB cable connected, it stays perfectly in one point for many hours, like a peg in a fence . The cable was about 1.5m long.

I did not do tests in motion.

[gpsjorgen]

Thanks for the extensive reply

Thank you for your interest in my tests.
I still have both devices, although your post motivated me to get rid of one. I am not comparing them anymore, because if I did, it would probably not look good from the perspective of my mental balance . In some details, the 66sr is better, especially in the track recording, it is more precise. More precise, i.e. the GPS track changes directions quickly according to your movement, and the GPSMAP67 smoothes the line more.
I did the tests by walking the same straight line, at different times of day (taking the dogs for a walk) and when I compared the lines that overlapped many times, it turned out that the 66sr painted a wider strip compared to the 67. This means that the 67 is more accurate in positioning.

My references currently the Fenix 7 (wearable) and Edge 1040 (bikecomputer). I always cycle using them both so I've a good feeling about them. They seem to be very accurate and tracks always overlap. So when I bought the GPSMAP 67 I took all three of them on a MTB ride. This gave some expected results in which Fenix and Edge agreeing with each other as usual and the GPSMAP 67 deviating. I posted this on the Garmin forum. I started a more thorough compare on these GPSses. I will post in a blog upcoming days.
Sneak preview: I find that the GPSMAP 67 is more precise than the others. However, I am still working on accuracy. And I will do some comparsion under harsh conditions (foliage e.g.).
Note that all three devices have the same GPS chip, so from that perspective they should not differ. However, as stated above I find difference between GPSMAP 67 and the other two.

What I encountered was a very remarkable problem: when left stationary the point cloud is pretty precise like you stated, provided conditions are ideal (unobstructed sky view, device upright). Average error: 1.1 m for 12 hours of measurements, every second. However, when conditions are less perfect, the measured coordinate starts to wander with errors up to hundreds of meters (no not the cumulative distance, the recorded coordinate!). See my blog for a full report. I get the impression that maybe the device also uses the electronic compass and/or acceleration sensors when conditions are not ideal and the issue is some dead-reconing issue. But this is guessing...

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I am currently in discussion with Garmin Support NL because I believe this is a bug. It is quite difficult to convince them.

Sometimes the 67 restarts more often, especially when I use the search engine. I also do not like the new menu with map layers, I never know if the maps are on or off. The screen zoom is also one step lower than the 66sr, I often want to zoom in to see some detail but I can't. On the plus side, the low battery consumption and the fast refresh rate.

Battery consumption is marvelous. Isn't the zoom level defined by the map?

Dear moderators, I realize this maybe is a bit of topic, appologies for that. But I am not allowed to send PMs, otherwise I might have sent a PM. On second thought, maybe this is interesting for other readers.

[JungleJim]

[..]

I am currently in discussion with Garmin Support NL because I believe this is a bug. It is quite difficult to convince them.

[..]

You might want to try Garmin Support US instead of NL. In my experience they are more willing to accept that a finding is a bug and also are more knowledgeable than NL.

Best way to reach them is via chat: go to the GPSMSP 67 support pages on support.garmin.com and use the Chat button on the bottom of the page,

[GPSrChive]

Best way to reach them is via chat: go to the GPSMSP 67 support pages on support.garmin.com and use the Chat button on the bottom of the page,

I do not find any 'Chat' options, please advise!

Garmin GPSMAP 67 Support Page

Garmin Support Page GPSMAP 67.png

[JungleJim]

Yeah sometimes the chat option is not shown on the GPSMAP 67 support page, and you need to select a specific article (any will do). And chat is usually only available during US business hours.

[GPSrChive]

Thank you Jungle Jim, I will check that out later this week!

[GPSrChive]

Dear moderators, I realize this maybe is a bit of topic, appologies for that. But I am not allowed to send PMs, otherwise I might have sent a PM. On second thought, maybe this is interesting for other readers.

This is exactly the kind of information we appreciate being posted here! Thank you for taking the time to share with us. A new report has been sent to Garmin software engineers requesting more attention to this very old issue.