Related
Options

GPS Accuracy

lucky1976
over 3 years ago

Any idea on the difference in accuracy between the GPS setting versus the All Systems and All Systems + Multiband?

  • 0 over 3 years ago in reply to 7162912
    7162912 said:
    Thx a lot, I was wondering how significant was multiband in real life, it seems not much, at least for now. How challeging was the track? Any tall building near by, tree cover or similar..

    The last picture was done on an alley with trees covering the pathway. Frankly, I cannot see any difference between the two watches. Battery life is significantly shorter, though. I charged both watches a couple of days ago and now I get
    - 66% for the 7X Sapphire
    - 75% for the 7X

  • 0 over 3 years ago in reply to Marc_v_L
    Marc_v_L said:

    This website gives you a very good insight regarding the accuracy. And compared to other watches as well as Garmin handhelds. 
    He concludes that Multi-Band really helps with accuracy for both the GPSMap 66sr and the fenix 7 sapphire editions. 

    https://www.navigation-professionell.de/en/garmin-fenix-7-gps-accuracy-review/

    I'm not sure it this is really his conclusion. I read "... a few more rounds would be necessary...". I'm using the 7x vs 7xSapphireMultiband for 2 weeks now. I really cannot see much difference! The watch on the left wrist always looks better than the one on the right ;)

  • 0 over 3 years ago in reply to 7162912

    https://github.com/uli-heller/uli.heller.cool/tree/gh-pages/garmin-6x-7x/data
    ... contains the GPX tracks I recorded with various watches, in case you'd like to examine them

  • 0 over 3 years ago in reply to UliHe42

    , what do you use to visualize the tracks so that individual positions are visible as dots?

    Have you tried going the same switchbacks downhill? I find that 6X is significantly less accurate at a faster pace, which makes it far worse at cutting corners. It would be interesting to see how 7X behaves in comparison. 

  • 0 over 3 years ago in reply to silentvoyager
    silentvoyager said:

    , what do you use to visualize the tracks so that individual positions are visible as dots?

    Have you tried going the same switchbacks downhill? I find that 6X is significantly less accurate at a faster pace, which makes it far worse at cutting corners. It would be interesting to see how 7X behaves in comparison. 

    I'm using https://sourceforge.net/projects/jgpstrackedit/files/binaries/ - JGPSTrackEdit. I'll do a downhill within the upcoming days

  • 0 over 3 years ago in reply to silentvoyager

    Left - blue - Fenix 7X Sapphire multiband active on the left wrist
    Right - ref - Fenix 7X on the right wrist

    I see no difference! Even the GPS loss towards the top of the track looks similar. I tried to run "fast" through the park. No cutting of corners.

  • 0 over 3 years ago in reply to UliHe42

    Alright, I walked the same route yesterday and today. Yesterday with All Systems + Multiband, today just 'All systems'. I have to admit, unfortunately, that the tracks look nearly identical. Same errors. The one without Multiband almost seems smoother as well...

    I really hope this is something that will get better with future software updates, cause right now it feels like it is not using the full potential of Multiband. I do believe this is a good technology, as my GPSMap 66sr is dead on with accuracy, even when walking through a city with high buildings and narrow streets. 

    I'm happy the tracks are pretty accurate overall. Just fingers crossed that it'll get better. 

  • 0 over 3 years ago in reply to Marc_v_L

    I don't know the area you walk but when conditions are good enough, more satellites, more bands doesn't have to increase accuracy. 'Cos it's already good.

    For example, on an open area the device can fix to a lot of GPS satellites and signal is good. So it'll give good results. Enabling it to fix to Glonass, Galileo etc. more systems may not increase it, as it's already good. Multi band is the same. If conditions are already good, it may not add a lot to accuracy. It'll probably help in conditions like tall urban building corridors etc.

    Also there are already other factors like, antenna size, watch being mounted on a moving arm, processing power it's let to use etc.

  • 0 over 3 years ago in reply to sis651
    sis651 said:
    Multi band is the same. If conditions are already good, it may not add a lot to accuracy.

    The main thing that multi-band helps with is discarding multi-path (reflected) signals. For example, when running on a forest with tall trees the signal may be strong enough to start with, but there would be a lot of reflections, which makes it much harder to triangulate the position.

    Now, if we had a good antenna, that would help too. GPS signal is circular polarized and reflections change direction of polarization. A good antenna would selectively attenuate reflected signals so they would be discarded. But since there is no good antenna, using multiple frequencies from the same satellite allows the chip to figure out whether the signal was reflected (in exchange to some extra processing power).

  • 0 over 3 years ago in reply to Marc_v_L

    Multiband will get better in the next years. At the moment only about half of the GPS-Sattellites are sending a L5-signal, the number increases slowly.

    And as stated before: It will not make a very good track better. It will make a catastrophic track good because it tells the device which signals are reflected and should not bei used.

    I don't see the point in turning multiband off because it needs some more battery (the fenix has more than enough - even in multiband) and you don't see a difference for 95% of the time. When you have a glitch in the other 5% that you wouldn't have with multiband then you regret it. I would only turn off multiband if it makes tracks worse. And I haven't seen any hint for that.