Wrong elevation gain

Maxime Bouvier

Hello,
I have some problemts with the elevation gain computed by my suunto race S on bike activities (i did not track it with running). It overestimates by a lot (20% to 60%) the elevation (when compared to GPS colputed elevation or to a bike computer equipped with a barometer).

The altitude curve seems very noisy and I guess that the problem comes from this noise which is added to the elevation sum. I understood that the altitude is only measured with the barometer and that there is no GPS correction. I tried to wear my watch on the left and right wrist and there is no difference. I know that wind can perturbate the measurement but it seems very weird to me that the elevation is not corrected with GPS as the watch has offline maps. I would rather, as it was the case with my old garmin, not have access to elevation during the activity but computed with accuracy once the activity is finished.

I have several questions :

Is it a common problem?
Can it be a hardware problem?
The noise in the curve is a very high frequency noise, it is very easy to get rid off this noise with a simple lowpass filter. With this kind of filter, i am able to easily retrieve the right elevation. Why isn’t it implemented?
Can I gps correct the elevation with the suunto app?

I was very pleased with the watch but I am very disapointed with this problem as I am mainly (~80%) using it on my bike.

Thank you for reading me

sky-runner

@Maxime-Bouvier I think this may be an issue with your specific watch rather than a general issue with Race S. If anything, I find my elevation gain to usually be a bit too conservative. Perhaps your watch barometer sensor is dirty.

maszop

@Maxime-Bouvier The problem could be wind, water, the location of the barometer sensor relative to the ride direction, dirt, or a hardware issue.

Suunto doesn’t smooth out barometer readings, and any disturbances can cause much higher readings.

isazi

@maszop said in Wrong elevation gain:

Suunto doesn’t smooth out barometer readings, and any disturbances can cause much higher readings.

I heard, but have not tested yet, that some fixes for sudden increase/drop in pressure will be tested with next firmware.