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altitude measurement unit

PatR

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Perhaps re-think the MSL reference. The metric unit of measure is correct but none of the Yuneec products reference sea level pressure. They only measure changes in pressure relative to pressure at the point of take off.

So AGL, or above ground level, is more appropriate than MSL or ASL, which references “mean” or above sea level.
 
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arruntus

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Right, but I think the key in this case is
on the ground it measures 9.763 what?
If it's on the ground, it hasn't taken off yet, it doesn't have the engines armed, which is just when the zero altitude relative to the home is established, and on top of that, taking into account that in the image the data is accompanied by the GPS coordinates, I think it refers to MSL altitude.

Anyway, it's as simple as @paolo negroni telling us if he was near the sea 😁
 
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44:19'53"N 11:43'20"E ?
Are you near Imola?
Ground level there is about 100 M ASL.
I suspect you were hovering at about 10M AGL from your arm/takeoff location.
 
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h-elsner

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My EXIF data in the pictures contain always altitude from GPS. This is MSL (as it is recorded in the ST16 RemoteGPS_xxxxx.csv).
Emmetten.jpg
This is Emmetten in Switzerland.

br HE
 

arruntus

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44:19'53"N 11:43'20"E ?
Are you near Imola?
Ground level there is about 100 M ASL.
I suspect you were hovering at about 10M AGL from your arm/takeoff location.
Very good companion, I had not thought to look at the coordinates to check the height :D

Even so, I think that ASL height and error can come from a GPS failure? didn't have enough satellites? The H520 allows you to take off if you are connected to only 5 satellites (I think I remember the number correctly), but that doesn't mean strictly that you have a stable connection........... I would go there more, I have checked a lot of my photos and the height in the exif data correspond to the ASL height of the place where I took them.
 
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Very good companion, I had not thought to look at the coordinates to check the height :D

Even so, I think that ASL height and error can come from a GPS failure? didn't have enough satellites? The H520 allows you to take off if you are connected to only 5 satellites (I think I remember the number correctly), but that doesn't mean strictly that you have a stable connection........... I would go there more, I have checked a lot of my photos and the height in the exif data correspond to the ASL height of the place where I took them.
Smartphone photos get their ASL altitude directly from the phone's GPS module.
The Typhoon flight controller keeps a separate relative altitude using its barometer. It is zeroed at takeoff.
The ground station gets that relative altitude. The value in the CGO3(x) image properties looks like it is the AGL.
My CGO3+ jpg's show AGL also.
 

arruntus

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In reality MASL are over 100 m
You mean when you took the picture you were at 100m ASL? or MASL as you prefer. Or do you mean that giving a MASL data is only when you are above 100m? I don't get it right 🧐
 
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The IR image was taken at about 10m above your launch position.
 
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You mean when you took the picture you were at 100m ASL? or MASL as you prefer. Or do you mean that giving a MASL data is only when you are above 100m? I don't get it right 🧐
when I took the picture I was at 100m ASL
 
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44:19'53"N 11:43'20"E ?
Are you near Imola?
Ground level there is about 100 M ASL.
I suspect you were hovering at about 10M AGL from your arm/takeoff location.
Yes, on the hills near Imola, and I was on the ground.
 
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Smartphone photos get their ASL altitude directly from the phone's GPS module.
The Typhoon flight controller keeps a separate relative altitude using its barometer. It is zeroed at takeoff.
The ground station gets that relative altitude. The value in the CGO3(x) image properties looks like it is the AGL.
My CGO3+ jpg's show AGL also.
Yes, it is AGL
 

arruntus

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Well, it seems to change depending on what camera it is. The E90 shows me ASL, that's for sure.
 

PatR

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Imagine the mental arithmetic that would confound users if their drones reported altitude as AMSL. Most of them don’t have a clue what the height above sea level their launch point is to begin with. If they were standing on ground with an elevation of 2400’ MSL and flying 400’ higher their drone depicted altitude would show 2800’ MSL. I can easily imagine some operator looking at a depicted 2400’ MSL altitude before launch deciding he could not fly because he was already above 400’.

Yes, some of them are that dumb...
 

arruntus

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Imagine the mental arithmetic that would confound users if their drones reported altitude as AMSL. Most of them don’t have a clue what the height above sea level their launch point is to begin with. If they were standing on ground with an elevation of 2400’ MSL and flying 400’ higher their drone depicted altitude would show 2800’ MSL. I can easily imagine some operator looking at a depicted 2400’ MSL altitude before launch deciding he could not fly because he was already above 400’.

Yes, some of them are that dumb...
normally at the ground station you work with AGL, although many have options to switch between the two. But I believe that when storing the data in the images or when you have images, it is always with MSL height. At least with all the software I have seen.

I just checked the data with 3 different RGB cameras, with a multispectral and with the thermic and in all I see the MSL height.
 

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