You cannot disable the barometer unless you maybe know what wire to disconnect -- if it will even take off at all at that point. And, as Meta4 explained, the barometer resets to zero (or thereabouts) at startup, so altitude is always relative to your take-off point.
Okay i would not go so far too mess with the hardware, yet, since the P4 is still the best drone I have right now... Hopefully, this is changes until next year. getting off topic now, haha.
Does anyone know why the drone does not use altitude information from GPS? I mean, they are always in the footage's meta data so... the drone actually knows how high above sea level it is...
If you fly along autonomously maintaining 200 ft altitude and approach a 300 ft hill, you will crash into that hill. Basically, disconnecting the barometer would not help and doing so would make no sense.
Sure thing, my flight was located in a near flat terrain with almost no differences in heights / almost no profile. Maybe 6 - 10 feet difference over 2 km.
Yes, I see the 8 inches per mile figure quoted on the internet. That's 12.4 cm per km or 12.4 metres per 100 km... very different from 785 metres, which seems like a lot! Yet, two different 'earth curvature' calculators I found online calculate the 785 metre figure. I don't know what's correct.
If you want to calculate the curvature drop locally, say 1 km from your position, you can always take 8 cm (CENTIMETERS!) after 1 km. That's the ratio to go. But don't stress this out too much, since it's not actually accurate. It's getting more inaccurate when you use farther distances like 100 km! Even at 2 km you will not get 16 cm but rater 31 cm already. This is, because 8 cm / 1 km is a clear linear relationship, whereas the curvature of the earth is not linearly dropping. It sounds complicated but it's actually quiet trivial. The curvature of a ball/sphere is always exponentially dropping, otherwise it wouldn't be a ball. The people from
Earthcurvature make a good job, yet they also don't have the best equation for very long distances (see note at the bottom of the page).
While not directly an answer to the question I’ll throw this in…
If you program a mission with Litchi, you can specify waypoints to be a certain altitude above the terrain. Of course it’s not based on any kind of sensor input from the drone. Just terrain data from the maps they use in the mission planning software.
Thanks for that! I guess they use google earth elevation data. But you can also upload DEMs into your Litchi mission, pretty nice software to plan flights. Love it!
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So, when we now agree the drone does not fly straight, but can rather change its height above ground level (AGL) along a longer course, would you say my experiment is possible?
I repeat my experiment:
- I wanted to find out if I can see Earth's curvature in a photogrammetry 3D model (with the extent of several km) after loading in missions from my flight.
- Therefore I wanted to compare Point A at 80.00 m above sea level with Point B also at 80.00 above sea level (ASL).
- Point A und Point B are separate by 1 to 3 km. This would result in ...
1 km = 0,08 m
2 km = 0,31 m
3 km = 0,71 m
... drop in Elevation from Point A to Point B caused by Earth Curvature, although they are both at 80.00 m ASL.
Cheers
SvSz