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Garmin 955 Altitude Problems

2796681
over 2 years ago

I was really thinking long about buying a watch in that price range, but my upcoming vacation in switzerland tip the scale and i bought one.

During the Vacation i was very upset about the Altitude Measurement, it was regulary wrong... When i make GPS calibration it was precise and correct, but after short time (40-60) minutes i have 30-50m drift. Most times the watch show 30-50m less altitude than it actually was. I calbrate and check on waymarks and cabins and the GPS calibration values always matched with the waymarks and the altitude lines on the map.

So i investiated more in barometric values and if they could be the reason. On the days we went hiking the weather was very stable. So i am very sure that the barometric weather changes were not the reason.

Here i have some examples from a tour and the barometric changes on that days and especially in that short times frames are very limited and can not be the reason for that big drifts.

Here you see after 45 minutes i make GPS calibration and the value goes 38m high to the correct values of 2390.

connect.garmin.com/.../9282976959

The weather was stable and there were no big changes.

Here are similar examples, i dont know why this hole happend? i have recalibrated at minute 42 and 57

connect.garmin.com/.../9247367856

weather also stable

relabration at 1:27

connect.garmin.com/.../9228951580

stable weather

Is this a bug or is the barometric sensor crap? Any idea about this? thanks

  • 0 over 2 years ago

    I have not yet made the step on 955 because I read too many SW bug complaints, but we have the same problems on 945, from my checks and other friends of the forum (including fenix6), the altitude is too sensitive to temperature changes on the wrist, I guess this is also the case on the 955, among other things on the FR the altimeter hole is closed behind the strap instead of ventilated on the side like the Fenix series

  • 0 over 2 years ago in reply to Luca

    so the fenix has less issues for measuring altitude?

  • 0 over 2 years ago in reply to 2796681

    Surely it is easier to keep the altimeter holes clean, from what I understand the determining factors are 2: the temperature used too heavily by the algorithm and the cleaning of the holes from which the sensor acquires the atmospheric pressure

  • 0 over 2 years ago in reply to Luca

    i dont know if this is really the problem... When i go sportclimbing the barometer is very precise for measuring the height of the indoor walls. i think it could be more software  topic, the temperature issue sounds reasonable.

    support.garmin.com/.../

  • 0 over 2 years ago in reply to 2796681

    Interesting. Indoor walls could be a good test.

    How high are your walls?

  • 0 over 2 years ago in reply to 2796681

    I agree with you, it happens a few times that just doing the cleaning at home signals me goal reached 5 floors, I don't even go out the door

  • 0 over 2 years ago in reply to DPSK

    around 15 meters

  • 0 over 2 years ago

    I have exacly the same problem with a forerunner 255. 

    After 2 months of thinking that I had a defective unit, a friend bought the same watch and surprise: we had the same problem.

    We had the same values from the altimerer during all the activity: after climbing 100m altitude, the watches showed a value 10% lower than the real one. And after clim 400m the devitation was about a 20% making that totally usless for any propouse.The courious think is that when we returned to the starting point the wathches showed a height exactly with the same value of the moment that we started the activity. 

    I don’t know if the 255 and 955 series have a software bug or a crapy sensor.

    I hope that garmin is working to solve that problem..In my opinion this bug is not tolerable for a watches in that price range!

  • 0 over 2 years ago

    I found that I had the same problem. When hiking in Italy, I would calibrate the altimeter by GPS. By the time I reached the next marker, I would have lost 10% or so. By the time I reached the peak of a mountain, my 955 solar was showing 2200m instead of 2400+m. This happened for all my hikes. I had just gotten the 955 solar a few weeks earlier so I was absolutely disappointed. 

    Subsequently, what I found that helped was to turn off the barometer component of the altimeter - ie sensor mode to be set to altimeter only and not auto (which comes as default). This made my altitude readings more accurate (+/- 10m-ish). 

    I read the Garmin manual stating that if you expect changes in altitude, then the altimeter mode might be better and if one didn't expect changes, then the barometer mode was fine. I don't really understand the logic - accuracy is always important isn't it? My guess is that the barometer input helps save battery for the altitude readings (instead of purely relying on GPS) but if so, Garmin should clearly state so. I'm now sticking to altimeter mode only (don't see the value of the barometric input)! 

    Try the above to see if it works for you?

  • 0 over 2 years ago in reply to 2796681

    No, it is worst. I had Fenix 6 pro solar and it was a nightmare.

    Please Garmin don't touch anything in 955 cause it's perfect