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Altimeter Auto Calibrate During Activity

georgiawx
over 6 years ago

Just got my 945 yesterday, first activity today. This brought up a question...I see the option to set auto calibrate to continuous during an activity and that is default, and I can set it to at start, but I don’t see a way to specify if it uses GPS or DEM when it auto calibrates. Does anyone know which it uses?

Thanks,

SA 

  • 0 over 6 years ago

    I'm pretty sure in that scenario it's using 3D GPS for the elevation fix since the same function exists on watches that don't have maps.

  • Former Member
    0 Former Member over 6 years ago

    i have a similar question. How often does the Watch do the calibration during an activity.

  • Former Member
    0 Former Member over 6 years ago

    i have a similar question. How often does the Watch do the calibration during an activity.

  • Former Member
    0 Former Member over 6 years ago in reply to Former Member

    Whatever you set it up to do.  Either "at start" or "continuous". 

  • 0 over 6 years ago in reply to R_Tellis

    Actually I did some testing today, it seems that it isn’t auto calibrating at all even though I have it set to in the settings. I set the altimeter to 1000 ft below the actually and when the activity started, the elevation stayed the same. I left it on for a few minutes and it never changed. So I am not sure if it’s a bug or if what I expected it to do is not as is intended. Flushed

    SA

  • 0 over 6 years ago in reply to georgiawx

    This stuff It has never worked since Epix... no matter what you set, nobody knows how altimeter calibration works... also if you set auto cal "not during" activity, it doesn't work... 

  • 0 over 6 years ago in reply to renton82

    I have “not during activities” set to yes and oddly enough it looks like it did auto calibrate overnight. I can see the jump in the elevation of about 30 feet on the watch graph. Based on the elevation it changed to, I believe it used DEM for the source.

  • 0 over 6 years ago in reply to georgiawx

    However i think it's pointless... how about if i live at 24th floor? Garmin should let us to choose if set an home point with fixed altitude or let the watch knows its altitude from DEM...

  • 0 over 6 years ago in reply to renton82

    I agree, it would be pointless for some...but not for all. One of the early Fenix versions allowed you to calibrate elevation at the start of an activity based on a saved location where you could enter the elevation manually. They did away with that in later versions which is unfortunate because I really liked that feature. If they implemented something similar to that and then used it to calibrate during the night, then it should work well for all.

    SA

  • 0 over 6 years ago in reply to georgiawx

    A little more testing today and It seems that if you do a manual calibration just prior to starting an activity with auto calibration on, even if the elevation you manually set is way way off, the watch will not perform an auto calibration....however, if you have not manually calibrated recently, the auto calibrate does indeed work, at least at the activity start. I guess the algorithm it uses checks to see if you have recently calibrated and if so it does not auto calibrate, assuming you entered a good elevation and not an erroneous number. Kind of makes sense because why would anyone enter an invalid elevation?....lol.

    it also appears that it uses DEM and not the GPS elevation for this calibration.

    SA