Subterranean outdoor activities with Galileo

[Łukasz Szmigiel]

There used to be a bug - a long time ago (fixed in some of the firmware updates) - that made a sudden drop (or rise, I can’t remember) in altitude on the start of the activity when using Galileo. I’ve been observing similar behavior for some time and was wondering if it’s firmware related or maybe there were some internal changes to GNSS itself?

For example, I’ve started today’s run, according to SA at -36m and quickly (around 60s) went to nominal ~120m. What’s interesting - the track was acceptable - pretty typical for first few minutes, with some deviations but nothing bad like being 100m off the actual location.

Apart from the start, the track was top notch, no signal losses or weird deviations.

So I got an ascent of 162m when it should be around 10m.

[DMytro]

@łukasz-szmigiel oh, I didn’t know it might be Galileo related. I get it almost every time of I start workout directly after arrow turns green, if you give it few more seconds it should be fine though.

[Łukasz Szmigiel]

@dmytro I usually wait a little longer or start running without actually starting the workout and it’s mostly OK but it goes bonkers from time to time (like today). I thought that this problem was sorted out but maybe not?

[DMytro]

@łukasz-szmigiel I didn’t thought of it as a problem tbh. It’s just that GPS needs time to settle and the arrow turns green not when the signal is great but when it’s good enough.

[Łukasz Szmigiel]

@dmytro yeah it might be a matter of how it’s tuned in to show that the signal is good enough (and it doesn’t care about VDOP) but I haven’t seen it with other GNSS which is strange. Or maybe I’m not using other GNSS often enough to notice?

[Tomas5]

@łukasz-szmigiel i don’t have problem with altitude at all or at least i didn’t notice. For example from last bike. But i every time wait for GPS signal befor starting excercise. And it took usually longer. Around 20-30 seconds sometimes less or more. Maybe you just need to wait few seconds more before starting excercise.

And latest hike:

[DMytro]

@łukasz-szmigiel I use Galileo and it’s there every time I rush the wait. I’ll try other combinations out of interest.

[Tomas5]

@dmytro i use galileo too.

[Łukasz Szmigiel]

Just a friendly reminder that a gigantic drop of altitude at the beginning of the activity is still there, mostly when using two GNSS, oftentimes Galileo. This is very frustrating, especially now when we have a brand new ascent / descent algorithm. Any chances it’s going to get fixed?

[Tomas5]

@łukasz-szmigiel did’t tried it yet with new firmware but since you mentioned it last time. I was looking at this and i have this issue too. Not every time but usualy it is few tenths or even hundreds meters. But there are some exceptions without any altitude drop. I use gps + galileo all the time. If weather stay good i will report tomorrow test with latest firmware. And in my case it starts on higher altitude and then drops down to real altitude. I just noticed you have it in oposite direction.

[Łukasz Szmigiel]

@tomas5 it typically drops from too high, approx 70 - 90 meters during first 30 - 60s of workout

[Tomas5]

@łukasz-szmigiel i been on bike today, no issue with altitude drop at begining. But before i pressed start i was waiting for another minute after green gps icon apeared because i was setting up navigation and suunto plus feature.

[Łukasz Szmigiel]

@tomas5 this is well known. Although I’d like to know whether I should wait for ten more seconds or two more minutes.

[freeheeler]

@łukasz-szmigiel
it is the first time I see it that obvious since the campground is really flat.
in this case, yes it would be helpful to distinguish between satellite lock and “altitude lock”

[isazi]

@freeheeler for activities shorter than 15 minutes the issue is that fusedalti may not kick in.

[freeheeler]

@isazi
I know, it was around 30mins

[Tomas5]

Today on bike i didn’t have problem with altitude at beginning. But it is funny that lowest point is 375m, highest point is 979m. But my ascent is only 557m which is less than difference between lowest and highest point. By suunto app map planer it should be around 800m. But without barometer i don’t have big expectations from this measurement.

[Łukasz Szmigiel]

@tomas5 I don’t expect it to be perfect. I just want to know when to start the activity my experience when trekking is that I usually get 1 - 3m error in altitude when checking on marked peaks, with S5 and Galileo. And I find it remarkable.

[isazi]

@tomas5 yes depending on the route itself you may see less ascent with baroless devices because of the 7m threshold.

[Tomas5]

@isazi yes probably this reason, when i checked altitude against marked peaks I have same result as @Łukasz-Szmigiel usually few meters difference, only rarely few tens of meters.