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Elevation jump after activity pause and device sleep

I was in a ride and stopped to eat and drink something, I paused the timer and the device entered sleep. After turning the device on and restarting the timer seems like the device recalibrated the altimeter using the current position and the DEM data. Is this behavior correct? wouldn't it be better that in this case the altimeter is calibrated to the last elevation?

This was with an edge 520 plus.

0 jerrek over 4 years ago

I would generally say that what happens for me (garmin 520) when I stop is that changes in the barometric air pressure are the issue. I am of the impression that as GPS units struggle to obtain accurate elevation data it uses the barometric pressure to determine the elevation after the initial start-up. When you stop if the air pressure changes a change in elevation is recorded. Due to the time of day i stop at a local café i often get drops in elevation resulting in me being below sea level.

0 fabian over 4 years ago in reply to jerrek

What you say is a problem with the altimeter that we just have to accept or implement some workaround.

In the activity from which the graph I uploaded was made the start altitude was off by about 20m, I don't know from where the device got this altitude, the DEM data says that for the start position the altitude is 590m but it logged 610m, maybe it got it from the GPS data?.

The big jump in altitude after the pause could be fixed by calibrating the altimeter to the last know altitude (aprox 790m in this case) and not to the GPS data or DEM data, that would not give the correct absolute altitude but the height would not change like a step and the elevation change would be correct (0m).

If the device did this, the altitude would not have that jump even if there was a big change in pressure or temperature.