Doubt about Suunto 9 Baro altimeter/barometer calibration
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@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.
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@flypg if it’s the same algorythm that is used in the ambit3 peak for automatic mode then:
When in watch mode, it messures every 10 sec. if you move up/down more then 5 meters in elevation (around 0,6hpa) in 3 minutes, it switches to alti-mode. when your are moving less then 5 meters in 12 minutes the watch switches back to baro-mode -
Thanks @mario_b! Now I can understand for what on 1st try the reaction not was immediately and I got better results on 2nd try.
it messures every 10 sec
Wow, I imagined that should be a lower value, by this I expected a faster response in the update of the altitude readings. But really not need a faster update in watch mode, because for this I have the Sport Modes.
Thanks to everyone again! -
@flypg it counts higher than 3-5m variations in 12 minutes. If you would go a bit more low then both devices should react the same.
That is to wipe out pressure changes as we talked before
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If you are at a constant altitude (less than 5 meters of vertical movement within 12 minutes), your watch interprets air pressure changes as weather changes and adjusts the barometer graph accordingly.
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Thanks again to everyone!
Yes @Dimitrios-Kanellopoulos, this explains that on all my attempts I generated a altitude variation > 30m in less than 12 minutes (because I went up and down several times more than the 2 tests).
The only that is not totally clear is the variation of 1st try that the S9B not registered this +4 of when I went up. -
@Dimitrios-Kanellopoulos I have a Spartan Ultra: I’m sitting at the moment in my office at 214m above sea level. I know from the weather station on my altitude just some 2km away, that we have 2015.4 hPa at 30 C temperature. My watch shows me 2021 hPa. If I like to have a correct pressure reading, I would have to change the altitude to 165m. SO how can I bring this together to see correct altitude AND correct pressure?
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@flypg said in Doubt about Suunto 9 Baro altimeter/barometer calibration:
If you are at a constant altitude (less than 5 meters of vertical movement within 12 minutes), your watch interprets air pressure changes as weather changes and adjusts the barometer graph accordingly.
I published this myself a couple of weeks ago
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@johann-fuehrer is it sea level pressure? Can you give me now a coarse location (town)? I can look that up for you
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@Dimitrios-Kanellopoulos
https://www.zamg.ac.at/cms/de/wetter/wetterwerte-analysen/wien/luftdruck/?mode=geo&druckang=redIt’s Vienna and “Wien Unterlaa” is the station I mentioned …
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@Dimitrios-Kanellopoulos … and yes, it’s seal level pressure. Local pressure is about 993 hPa
You can switch in the pressure chart caption!
