Suunto vertical ascent/ descent totally incorrect

freeheeler

@maszop
I know what you mean and I saw this kind of measurements when road cycling. it is the activity where you point the sensor directly into the wind.
it doesn’t happen if you slightly cover the sensor holes.

I have put my watches in many different situations and cycling headwind is the worst. actually it is the only bad situation in my experience. there’s a workaround for it to put the watch on the handlebar.
so in my opinion it is the best compromise across all kind of sports.

maszop

I may be wrong, but I think it could be easily solved using the same principle as calculating distance based on GPS data.
To simplify, the position is recorded using GNSS every second, which gives 32,400 measurements for 9 hours. If all these points were connected with a line, the same absurd results would be obtained. This does not happen because before calculating the distance, the route is simplified and fewer points are used.
By the same principle, it would be possible to remove such noise from redundant measurements. It seems that these measurements are still too many for “slower” sports.

pilleus

@freeheeler said in Suunto vertical ascent/ descent totally incorrect:

it is the activity where you point the sensor directly into the wind.

With the Vertical it is impossible to have the sensors in the wind when mounted on a handle bar, because the openings of the sensor point towards the driver and not forward (below the Sunnto logo).

Or are these not the openings for the sensor?

freeheeler

@pilleus
absolutely correct.
I usually wear my watch on the wrist, even for cycling and mtb. I do put watches on the handle bar for testing purposes. depending on the speeds, position of my hand, headwinds, gloves, jacket sleeves etc. there can be differences in total ascent and they are visible on the graph similar as in @maszop ‘s graph.

pilleus

@freeheeler

I never had issues with a Suunto or other watch while cycling. Neither on the handle bar nor on the wrist. And I am on the bike every day and often have 500 to 1000 meters of ascent.

An easy way to check it is in Strava the auto correction or a gpx viewer.

I’m glad to have no problems with ascent/descent.

freeheeler

@pilleus
do you have a bike with dropper bars?

pilleus

@freeheeler

No, why should I torture myself? If I want to go fast, I ride a velomobile or a fast recumbent bike …

freeheeler

@pilleus
you made me notice that I wasn’t precise enough. on the roadbike the hand position is often different to any other bike handlebar and hence the position of the sensor holes…

pilleus

@freeheeler

Yes, but I think it doesn’t matter. On my recumbent bike and trike I often let my arm hang down and the sensor holes are directly in the wind. No negative impact so far for the reading of the barometric pressure.

pilleus

Strong winds can affect the air pressure around the sensor, which can result in an incorrect barometric altitude reading. Typically, an increase in wind speed results in lower air pressure, while a decrease in wind speed can result in higher air pressure.

If I have the severe weather alarm switched on in my Suunto watches, then warning messages should constantly come during the changes if the wind so often affects the barometric altitude measurement.

Has anyone noticed this yet?

freeheeler

@pilleus
yes and no.
yes, I have received several storm alarms since I have my Vertical.
no, it never happened to me due to winds, because it needs a certain pressure drop over a specific time

Swaddy61

@freeheeler Ditto - Several storm alarms with SV when there have been storms coming, and none at any other time.

maszop

@pilleus In my case, i.e. for activities such as hiking, mountaineering, trekking, what you write about usually does not matter that much (directly) because the current altitude is more or less correct (we are talking about mountainous terrain, so some inaccuracy does not matter), I can can accept them even in strong winds.

The problem is that there are too many of these results, all with some small error because this is how the barometric altimeter works, which add up, giving a completely incorrect total result.

With little wind, these deviations are not large enough to significantly affect the overall results. In stronger winds it is very visible - sometimes over 1000 m additional climbs.

Instead of fighting the wind, which is impossible anyway, it is better to simply introduce a filter that would remove the noise of too many results.

To start with, the simplest filter to remove some unnecessary altimeter’s records, and then over time it can be improved by introducing more sophisticated algorithms.
This could be done as an additional option to be turned on during or after activity (because it would certainly reduce the accuracy of the measurements somewhat), when it is clearly visible to the naked eye that the elevation sums are completely wrong.

pilleus

@maszop said in Suunto vertical ascent/ descent totally incorrect:

The problem is that there are too many of these results, all with some small error because this is how the barometric altimeter works, which add up, giving a completely incorrect total result.

May be I do not understand the problem, because it never happens to me since I use watches with barometer and gps (cycling, mountain biking, walking, running, in different areas, the Alps included).

Do you use only barometric altimeter without gps?

Brad_Olwin

@maszop Ski Mountaineering on the uphill is as slow as hiking. Yes, I am often off trail, I scramble up 4300m peaks in the summer and am often out for 7 to 8 hours. However, in the winter it is much windier, sometimes so windy that it can be difficult to see from blowing snow. I already asked several questions for potential fixes, have you tried these?

maszop

@Brad_Olwin This applies to 2 Suunto watches, 9PP and Vertical. A lot of time has passed since the release of Suunto 9 Peak Pro and this problem repeats very often in both watches, regardless of resets or cleaning (these were brand new watches).

Altitude graph
Suunto Vertical shows 1553m total climbs. Totally absurd in very strong winds.

Laps

Link to this activity (I had to stop further hiking due to the gusty wind):
https://maps.suunto.com/move/maszopmz/65b4e463aecad96a9da9c27f

cosme.costa

@maszop I do not have a SV yet but I have a S9B and have seen a very few times this issues and all of them match with the potential issues. If you have this issue with two watches could be some factor that affects equally both watches. I mean, I can complain of some things of Suunto but ascent and altitude is 99.9% of the times spot on. Moreover Suunto is recognized to nail it with this.

If I were you I would try to understand what could affect to this. As you said doesn’t happen always, so if it is a software bug and your activities are very similar this should happen always, shouldn’t it? I also understand that when you are at home the baro trend is logical, not fluctuating randomly?
Do you know the altitude in the summit? It is correct in the watch when you are in the summit? Are you leaving the watch do its magic with Fusedalti (full autoimatic)? How is the GPS track, do you have always GPS signal? Could be, that for some reason, when you hike you cover the baro sensor? Rain? Snow? At the end there is no much more secret from user side with this technology.

maszop

@cosme-costa I used Suunto 9 Baro and the problem only occurred a few times in the same weather conditions. Strong, gusty wind, some rain, generally nasty weather.
In the case of 9PP and Vertical, this problem basically always occurs under such conditions.

During the same hike, my friend went a little further with his 9 Baro and his watch showed about 900m of ascent. Probably a bit too much too, but not as absurd as Vertical with 1553m.

Apart from those cases with bad weather (where the altimeter shows basically correct values on the peaks anyway), there are no other problems or errors - in good weather, on a daily basis, etc.

maszop

And again.
Suunto Vertical shows 4456m ascent instead of about 1400. Wind about 60km/h.
Altitude graph

Brad_Olwin

@maszop I just did a very windy run and had overestimates as well in elevation gain. Not as bad as yours but it happened on the Vertical. It does not happen often to me and I might consider putting the watch under a sleeve as this would likely help. I was changing directions often so the wind hitting the sensor was not all the time. My graph has the issues yours does with lots of little spikes. It can happen, not sure much can be done about this as I have seen the same issue with an Apple Watch Ultra. The sensors have to be sensitive to detect small changes in pressure; enough wind in the right place will affect it. Maybe Suunto can make this better, I am not sure if that is possible.
BTW I have had worse issues like this on the 9baro and less issues with the Vertical, the sensor is in a much worse position on the 9baro.
I can dig up the data if you like.