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Altimeter and elevation issues still occurring (calibration & temperature)

a77
over 1 year ago

Setttings

Forerunner 955 Solar (16.19)

Altimeter Settings:

-Auto Cal: On

-Sensor Mode: Auto

Issue

The elevation drifts upward during almost every run. For activities where I start and stop in the exact same point, the ending elevation almost always higher. I always calibrate the altimeter to the DEM right before each run. I previously contacted Garmin Support and they said to just try cleaning the watch more frequently. I have now been cleaning out the sensor port (as directed here) on a weekly basis and it still is an issue. These aren’t huge spikes in elevation, but they make me question the quality to the elevation data compared to other watches.

Temperature

I noticed that this issue is worse when the temperature of the watch drops during an activity. I confirmed this with a fridge test. After placing the watch in the fridge for 30min, the watch temperature dropped from 74F to 43F, and the elevation increased by 30ft. When I overlay the temperature graph on top of the elevation graph for my activities with elevation drift, the watch temperature usually decreases sharply in the first 15-30min and then stays the same for the remainder of the activity. I have also noticed this behavior without recording activities. If I go for a short out/back walk and calibrate the elevation at the start and then monitor the altimeter widget during the walk, the elevation is usually higher on the way back as the watch temperature decreases.

Comparison to Fenix

I understand that environmental factors affect the altimeter, but I have seen other watches perform a lot better. For example, during a recent 12 hour run I calibrated the start elevation at 520ft using the DEM and the elevation at the end of the run showed 910ft (I did not start/end in the same place). The correct ending elevation based on the DEM should have been 650ft, so the altimeter drifted up by 260ft during the run. Someone I ran with used a Fenix 6X and their ending elevation was right near 650ft. Update: I added in the comparison graph in the comments section. Its weird to me that older watches would provide better data than newer watches. It seems that maybe the Fenix series are not affected by temperature change and/or they automatically re-calibrate the elevation during the activity (as suggested by the Garmin page here). 

"Before starting the timer, the elevation data field on the watch will preview the calibrated elevation.

Throughout the activity, the watch uses DEM mapping data, and GPS elevation to make adjustments to altitude for any altimeter drift due to pressure changes caused by a weather event during an activity."

Another Example

A recent test by DC Rainmaker (from here, picture below) also showed several watches having extremely similar elevation data and start/end elevation after a 12 hour hike (including the Forerunner 965). This was a long activity and several brands (including Garmin) seemed to have pretty good elevation data, where I still seem to have some issues even on shorter runs.

It would be nice to be able to trust the elevation data a little more given that this is the top Forerunner model. It seems like there could just be a setting to enable auto-calibrate during activities if there are major changes in certain environmental factors (especially temperature). Maybe it would just be copying how the Fenix 6/7's work, since they seem to be more accurate.

 

Does anyone else have similar issues with elevation?

  • 0 10 months ago

    I have the same problem and I'm sure it can be solved with a software update. During running activities everything is as you described. if I stay at home the altitude changes based on the temperature, but if I don't wear it and leave it on the desk the altitude doesn't change as it should. 

  • 0 10 months ago

    Hello guys, I have the same issues, but last winter I didn't have them. The bad thing is that I am on the beta program. I will appreciate if someone from Garmin can take some action because for trail running the watch is almost useless...

    Picture after I wake up.

  • 0 10 months ago

    I noticed my elevation levels were odd about a week ago - sitting around 4000m - 8000m when I usually have 130m as a starting point. Even if I try to recalibrate it the elevation immediately starts increasing even when I'm sitting still! It's very frustrating. As I'm not the only person experiencing this issue, this probably needs a software update from Garmin asap, pretty please?

  • 0 10 months ago

    In my case elevation drifts downwards due to cold temperatures.

    This is a 20km run on a 2.2km circuit, started outside home with watch at about 25°, outside was 4°

  • 0 10 months ago

    One more thing. I always do a separate activity for warmup.

    Set altimeter before start with DEM (find correctly 216m for my location), do 10min warmup run, stop activity, wait 1min before starting a new activity for training session. Then start a new run session and before calibration with DEM it says "235m", in a place with similar elevation of my home! It misses the altitude of 20m in the space of just 10 minutes due to the watch cooling down!!

  • 0 8 months ago

    Exactly 100 The same problem here. I am on 18.22,  but I have even on previous versions. I have read two posts and it looks life it is a HW problem - replacement helped.

  • 0 8 months ago in reply to JarVal

    I have the same problem and was also first thinking that it was software-related since I have been on the beta programme for some time.

    But if that was the case, I am sure that we would see even more bug reports.

    In my case, the temperature-effect to the elevation readings is very extreme: I get up to 200 meters of elevation change just by changing the location of the watch from inside (20°C) to outside (8°C currently).

    During activities in relatively flat terrain (+-20 meters), the elevation diagram looks like this:



    You can really see how the temperature drop when going outside and starting the activity correlates with an enormous drop in elevation.

    With enabled height correction (through Garmin Connect Website), the profile looks like this:

    I have calibrated barometer and altimeter numerous times and cleaned the watch according to the Garmin instructions to no avail.
    I suppose it is time to contact Garmin support for a replacement.
    Apparently, due to the number of people with the same issue, the barometer sensor is quite sensitive

  • 0 8 months ago

    I got similar behavior of altimeter on mine FR255. I noticed when my watch started counting 10+ floors climbed per day, despite I was walking at sea level on altitude change of maximum 1-2 meters. Sent it to warranty and got a new watch that works correctly. It seems that Garmin altimeters degrades over time...

  • 0 8 months ago in reply to Miky

    I experienced the same problem while cross-country skiing. The profile in the picture shows a circuit about 0.5 km long, which I completed twenty times. The difference in height between the first and last lap is about 9 m. I originally thought that the atmospheric air pressure rose during the one hour that this activity lasted, but then I found that it was constant throughout. It is possible that the reason was autocalibration or a change in temperature. When I looked at records of older activities that took place in the summer, the recorded elevation profile was more accurate. I hope the altimeter will be more stable in the coming summer.

  • 0 8 months ago

    Same here. Had my 955 watch replaced. Worked for 2 months and now im climbing 20 stairs a day again, while it should be around 4.