5S Plus incorrect altitude

Former Member over 6 years ago

Owner of a new 5S Plus, my first Garmin wearable. My primary use for the watch will be backcountry hiking and skiing where I want to know my current altitude. Went for a long hike yesterday in the Tetons. Started a Hike activity as I left the trailhead (I didn't notice whether the altitude was correct at that time). I loved the Hike activity data screens, just what I'm looking for. Climbed Prospectors Mountain which is 11,241 feet high. At the top my watch said I was at 10,800.

The altitude being off by 400' made the watch rather worthless for my primary use (also, the fact that the watch ran out of power 10 hours into my 13 hour hike was sub-optimal, but I expect I can figure our a way to use less power while on long hikes).

I've spent a few hours poking around the forums this morning and it seems as if there are lots of problems/user-misunderstandings about Garmin wearables' altitude but I did't see exactly the problem I had yesterday.

Did I do something wrong? Why, when the watch's map "knows" that I'm on top of an 11,241' mountain did it think I was 400' lower?

Thanks for any help or comments.

Will

0 Crispin_Ellisdon over 6 years ago

Some more official stuff on the Garmin Websites that explain how things are supposed to work:

Altimeter Auto Cal. settings https://support.garmin.com/en-GB/?faq=Vdz7RVePPV7wm1gO2d46TA&productID=603267&searchQuery=auto%20cal%20not%20during%20activity
Switching between elevation lock and MSL pressure lock https://support.garmin.com/en-GB/?faq=J2WVA0dss82BNpphPYWq56&productID=603267&searchQuery=auto%20cal%20not%20during%20activity

0 Former Member over 6 years ago

Allan - thanks for your help. I am quite familiar with barometric altitude as I have used a Suunto Observer for many years. In stable weather conditions the Suunto would give quite reliable and accurate altitudes.

Crispin - the Continuous Mode is exactly what I expected the watch to do. For a hiking activity I typically have my feet on the ground so DEM data is very good in the areas I travel. On my hike yesterday I did a manual calibration at the Trail head. When I got to my high point, a pass 2,888 feet above the trail head, the elevation was off by 150 feet (the weather was quite stable). I manually calibrated the altimeter to the correct altitude of the pass and when I got back down to the trailhead the watch’s altitude was high by 150 feet again. I had UltraTrac turned on to save battery life so maybe that caused the problems. I will do a Nother shorter hike today with calibration set to continuous and GPS set to Normal (GPS Only).

Is there any reason to think that the latest beta will help with these problems?

I would really like to get the Fenix figured out as it is lighter and more comfortable than my Suunto Observer. But the way it is working now I may well send it back to Amazon.

0 Crispin_Ellisdon over 6 years ago

Is there any reason to think that the latest beta will help with these problems?

There is significant anecdotal evidence from accross the Fenix 5+, Fenix 5 and Forerunner 935 forums (all having recently received elevation errror updates in the latest betas - previously all sharing the same bug) is that there is a genuine reason to think that the latest Beta may well assist with your elevation observations (3.56 for Fenix 5+ series).

I’d also say the UltraTrac may not help (helps your battery life though). The reason being is that if your horizontal position is off by say 15 metres and you’re near to a steep slope, the DEM elevation at the incorrect coordinates will likely be wrong too, this messing up the continuous calibration feature. If you are going to use UltraTrac, you may be best turning the Continuous Auto Cal off; which will leave you with a pure barometer elevation mode (so you will need to Calibrate manually occasionally to account for weather pressure changes).