Elevation problem

Former Member over 5 years ago

I did read a lot of discussion here:

elevation-consistently-inaccurate-reading-too-low

Looks that I am not alone who has problems with elevation. Problem which happen in my case is ONLY during activity. I also think that there are several different problems.

I did check pressure and elevation graph in watch during the day (holding ABC and scroll), values were OK. I did compare pressure with my weatherstation and very close national weatherstation. I did stay at home during all day so altitude was same but elevation in watch change a little (+-5m).

I did start mtb ride at 5:30pm and for 1h ride I did make cca 17km. I did make several small up and down hills. Before I did stop activity I did see that elevation is not correct because I did start and stop almost at same place.

Here are graphs just after I came home:

you can see that elevation at the end is higher. I did start at 228m and stop at 264m.

pressure graph, I was SHOCKED, how pressure can change so much, cca from 1016 to 1022. I did find out that it happen during descent.

I did check my local weather station:

I also check national weather station, and there is also nothing strange. I did put marks to be able compare with watch 6 hours graph. I think, there is something wrong with sensor or with firmware of Instinct.

I did export activity to GPX and then enable elevation correction in web and export that too. Here is comparison

Blue is original GPX with elevation based on barometer. Green is GPX which has elevation correction enabled.

The significant change start at cca 0.55h = 33min of ride during normal descent.

In other threads someone mentioned sweat can make some problem. And there is also thread where rain is mentioned. Do you think that this can be problem in my case? It is 4 hours after I finish my activity now. Watch still showing wrong values of pressure and elevation. If it is problem of sweat or water then how long it takes to dry? or is it going to correct itself?

What I also know is that instinct is slow in elevation reading.

I can see that in fast descent. Another day I went slower on downhill and also slow down before next uphill. Results was quite OK. Of course, barometric altimeter will not catch all small hills.

Settings:

- altimeter auto cal = off

- barometer watch mode = auto , Tell the true, I don't understand this settings clearly.

thanks for any comments

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0 thomass001 over 5 years ago in reply to Former Member

Thank you for your hard work.

btw

I have made my own baro cover for training.

Ask me for stl-file.

0 kHanDaichi over 5 years ago in reply to thomass001

Hello,
Your cover is nice, because it holds without tape.
Are you satisfied with the results? alti/baro? heart rate?
Could you make the file available?
Sincerely

0 thomass001 over 5 years ago in reply to kHanDaichi

I will test it and if it's good, I will share it.

0 kHanDaichi over 5 years ago in reply to thomass001

Thank you

0 Former Member over 5 years ago in reply to thomass001

great :-) I like it

but not sure, this gadget could push watch from hand to much so accuracy of HT can decrees, anyway looking forward for results.

0 Artgrrl over 5 years ago in reply to Former Member

Thanks for this useful thread. I “upgraded” my Garmin recently from a Vivoactive HR to the Instinct because I am running a trail race for which I wanted an independent GPS. I live in Illinois and have been doing hill repeats on the same sledding hill, basically charging the hill. I have been very frustrated with what it displays. All five of these are the same hill which is at the same elevation. Running up to the same spot and turning around. There shouldn’t be a slow descent happening. There should be five even distinct peaks and flat space. Instead it looks like I’m going mostly downhill. In between the first and the second repeat, I walked a lap around the park. It’s flat as a pancake. I thought maybe smoothing was an issue so I went to the train station and ran stairs in the evening. Same issue. At the end of my night it said 35 flights up and 47 flights down. On the stairs it was only counting about half of my climbing and all my descending. I’m so frustrated.

0 dav.dc over 5 years ago in reply to Artgrrl

Hi Artgrrl,

From my experiences what you observe has the same origin as the "smoothing" issue: I also have (almost) systematically a slow descent of ~25m during the first 30 minutes of my runs.

Note that you can recalibrate the barometer with gps during your run. This will update the elevation but not the ascent/descent of your run, leading to odd things such as global ascent < elev max - elev min

When I don't wear the watch on my wrist (eg in my bag) I don't observe this. And yesterday I tried a home-made dirty gadget (piece of plastic with tape) and elevation profile was perfect, both for smoothing and these 25m descent.

However the tape itself was not sweat proof and stayed on my wrist when I took off the watch... So I really hope that Thomass001's gadget will work !

0 8759190 over 5 years ago in reply to Former Member

A few times I have noticed the bug occurs after I stopped for a short time and then continue cycling, after about 30 seconds. I wonder if there will ever be an update... too bad.

0 Danny over 5 years ago in reply to 8759190

Yes, this frequently occurs for me (running hills).

0 Former Member over 5 years ago

UPDATE #4

Ride 125: I am pretty satisfy.

lets check those two parts where BLUE (original gpx) is bit shifted from GREE (elevation correction).

second part is bit different, I think that GPS is not so accurate because there is dens forest. So I think, that true is between blue and green

conclusion, I will keep using gadget but will change routes because I am bored with same descent. Maybe if next ride will be OK, then I will try same one without gadget.