Altitude incorrect while hiking

[Sergei Ladeishchikov]

Hello! Today I went hiking in the mountains with my SV. I went through several peaks and the height on the SV did not match any of the heights of the peaks. SV has always shown a lower height with a difference of 60-80 meters. In the beginning, I used custom battery mode with good GPS accuracy. After I switched to performance, but nothing has changed. at its highest peak, SV was 75 meters short. Nearby was a man with a Garmin Fenix, and his height was 25 meters less than the peak. The weather was cloudless, no trees or anything like that. Tell me, is this normal or is there any problem? In the last campaign, I also noticed a difference in a smaller direction, but not so big.

[GiPFELKiND]

@Sergei-Ladeishchikov 60 to 80m incorrect altitude is very much if i in the mountains. Sounds not good. Do you reset before start your trip on a known altitude correctly?

[Sergei Ladeishchikov]

@GiPFELKiND I don’t reset or tweak anything at all, I let it work FusedAlti

[freeheeler]

@Sergei-Ladeishchikov
please observe your next hike if it happens again.
normally FusedAlti detects when the altitude is wrong and corrects it.
I’ve had a similar issue on a 1h run recently, when the watch showed 60m below actual altitude throughout the entire activity. once only, didn’t happen again.
please let us know in case you observe it again

[Sergei Ladeishchikov]

I also noticed that for 10 hours of activity with an external heart rate sensor and without using S+, the watch took about 20-22% of the charge.

[freeheeler]

@Sergei-Ladeishchikov
that’s roughly 2%/h and ok-ish with external HR, IMO.
internal OHR is more efficient than external.

[Sergei Ladeishchikov]

@freeheeler I also noticed that the total climb is the same as the route. Could it be that FusedAlti did not work in custom battery mode?

[Sergei Ladeishchikov]

@freeheeler Is 2% a lot? I always do activities with an external heart rate sensor (Polar H10).

[freeheeler]

@Sergei-Ladeishchikov
did you use maps, too?
2% is about to expect with external HR, but in case of maps being in use definitely it is realistic.

hmm, I am not aware of any setting that would deactivate FusedAlti. but for example a trail covered with trees could make it difficult for FusedAlti to measure correctly.

[Sergei Ladeishchikov]

@freeheeler I did not use the map so often, I already knew where to go. At the beginning of the hike there were quite a lot of trees. So, if FusedAlti couldn’t make an altitude adjustment in the first 15 minutes, then he doesn’t do it anymore?

[Sergei Ladeishchikov]

@freeheeler Thick trees started from the 7th minute of the hike.

[freeheeler]

@Sergei-Ladeishchikov
normally it does the correction within 15min, but as I understand should check throughout the activity if something changes again, e.g. pressure drop due to bad weather

[Sergei Ladeishchikov]

@freeheeler Should I or the SV check altitude throughout the activity? Doesn’t SV know GPS altitude, especially in dual-band GPS/GNSS?

[Mitch9]

For me the height accuracy of the SV is really great in the mountains. Mostly within 10 m for peaks which is amazing for such a device. Sometimes I calibrate the height (when the situation is right for it) but not always.

[babychai]

the accuracy sometimes depend on the location. some mountains my SV show higher and some mountains show lower altitude at the peak. so far within 20 meter range.
maybe the altitude shown on signboard at the peak doesn’t accurate as well. you can double check on the TOPO map.

[gone troppo]

My sv altitude is always very close on 1000+m mountains usually within 10m. I don’t calibrate it or anything before starting I just let it run

[Łukasz Szmigiel]

@Sergei-Ladeishchikov did you manually set elevation prior to the hike?

[freeheeler]

@Łukasz-Szmigiel
that’s not necessary but doesn’t effect either

[Łukasz Szmigiel]

@freeheeler I’ve read somewhere around the forum that if you set elevation manually prior to the workout it can disable fused alti for some time.

[freeheeler]

@Łukasz-Szmigiel
yes that was true until a date we can not tell anymore because it’s unknown
I did a test recently and it was confirmed by others. you can do what you want and when you want with manual calibration, FusedAlti will correct it anyway if necessary