Doubt about Suunto 9 Baro altimeter/barometer calibration
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@johann-fuehrer
I know I’m a bit offtopic since I am an old fashioned Ambit guy, but it seems to be a topic about fused alti, too?!On Friday I went on a biketour (the one that we had to dig out our phones and maps for since we could not create a new route in MC and could not sync SA to Ambit…) and while we were in the gondola to get to the start of our tour (yes, sometimes I skip the pedalling part
) I did the calibration manually as automatic calibration with fused alti always takes ages…
In SA, I noticed later that the total ascent and the maximum altitude must be wrong. Also the altitude profile is not really what it looks like on the map…
The orange dot was at the actual highest point which is on the map at about 1’600m.
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@TELE-HO You are sure your baro is ok? It looks like it could not keep up with a “quick” altitude change when going up (and also when going down). If your baro holes are blocked (partially) it might be that the higher pressure from the base that you had in your watch, could not get out through this holes quick enough and therefore showing a wrong altitude (too low). But it seems that later this gets better. But strange in any way…
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@TELE-HO would be interesting to see the change compared to a real altitude graph…
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@johann-fuehrer
yes, almost new watch and I am aware of the baro holes issue from my earlier Suunto Core…
The activities before and after were recorded without any issue, like I am used to.
I am pretty sure I confused fused alti with manual setting while “climbing” in the gondola and then immediately starting the activity. -
@TELE-HO
this is roughly the graph of the route when I draw it in MC map.
living sideways
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@TELE-HO AFAIK if you manually calibrate the altitude while recording an activity, fused-alti will be disabled. not if you calibrate it before an activity. would be nice to see this activity in MC
because allways when fused-alti calibrates the altitude for more then around 8 meters, you see the pressure change in the baro diagram. -
@TELE-HO Is it possible for you to merge this one and the recorded one in to one graph? Maybe quantified.io is helpful? I did nor use it yet, but have seen a lot of such stuff is done in there by others…
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@johann-fuehrer Jup that is possible
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@mario_b
yes I am aware that you switch off fused alti when manual calibrating during an activity recording.
Here’s the sea level pressure with the altitude profile.@Dimitrios-Kanellopoulos
I don’t know who to do an overlay… but if I do an overlay, it would be necessary to have it almost idential from the drawn to the recorded track to have the best comparison, right?
living sideways
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@TELE-HO update 2 activiteis / routes to QS.
Select them on the table
Press merge
Use the distance axis when viewing -
@TELE-HO for a GPX track you can get “real” altitude information here i.e. https://www.gpsvisualizer.com/elevation but I do not know how exact that is…
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@johann-fuehrer … it’s a 30m x 30m grid SRTM1
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Runanalyze!
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@TELE-HO perfect. i think you’ve being right, as you said, that i could be, because you calibrated it on the gondola.
as you can see, fused-alti is correcting the altitude all the time on the activity to a higher altitude. is the altitude value on the end of the activity nearly correct? -
@mario_b
yes, it is absolutely correct at the end.I just noticed that I’ve had a GPS precision issue for the first 35minutes of this activity anyway. I wanted to redraw the exact route but saw that the signal was off track at the beginning… it does not make sense to overlay my recorded move with a drawn route I think.
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@TELE-HO so i would say, there is nothing wrong with your watch. looking at the ambient pressure at around 930 (which is not anough for the swiss the last weekend) i think it was only a faulty calibration at start. then fused alti kicked in, and corrected the altitude until it was nearly correct. (>1005 hpa at the end sound more possible too).
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@mario_b same opinion. Somewhere at 1 h 15 mins after start it started to look ok.
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@Dimitrios-Kanellopoulos Thanks
. Again, sounds logic.
After my test that I described below I have this doubt: you know with which frequency the S9B take samples of the barometer to calculate and show the altitude? or which is the frequency that update the altitude displayed?I made a simple test using the S9B, Mobile with barometer and Samsung Gear Frontier. I went downstairs one floor (~4m difference).
1st try: S9B not show differences even after ~20sec or a bit more. Mobile and Gear displays the -4m variation instantly, the altitude on these both devices is continuing updating almost on each step that I do down.
I went up. Mobile and Gear displays the variation of +4m. S9B again no differences. After around 5 minutes, I see that the S9B display me a -4m difference (wrong), looks like displays me the value from when I was down, but do not register that I went up again.2nd try: Mobile & Gear again displays correct results instantly and continuously. S9B: I decide give more time waiting on each floor. After few seconds or minute waiting on the lower floor, start to display me a variation of -3m, after few minutes I get the -4m. I went up again, +4m after few seconds or almost a minute.
Results: Mobile & Gear displayed correct value all the times and instantly. S9B worked tricky. One time showed me a correct result but maintained the difference error created on 1st try. 2nd try was perfect, but need sometime to show me the correct values.
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@flypg I have read about some threshold value which must be reached until an altitude change is recognized by the watch, I think it was about 3m or somewhere in that range. Maybe this kicks in as well …
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@johann-fuehrer Thanks, yes, this is why I would like know with precision to understand a bit more the watch. I think that also exist some timelapse to process this or display this and this results in the “delay” that I see to display the information.
