I'm sorry, but I can't find the answer to this anywhere. I'm sure it's somewhere, in the manual perhaps, or even in this forum, but I just can't find it ...
After learning the basics on completely flat ground, I'm soon going to be flying in an area of variable elevation. I know as a Private pilot that there are two kinds of altitude, and it is vitally important to know which kind you, or a map, or controllers, are referring to: AGL (above ground level) or MSL (above mean sea level, measured by altimeter).
So when I am flying my Mavic 2 Pro, and it says I am 100 feet high, how is that measured? Relative to the ground below the drone? (And how does it do that?) Relative to Home? If it's the latter, doesn't that mean that in certain circumstances your altitude might be a negative number — if you launch from a mountaintop and fly down slope?
No, that wouldn't make sense. It has to be AGL. So if I launch at a mountain top and fly away from the mountain without changing relative altitude, the altitude reading would nonetheless rise, relative to the ground receding below — right?
And how does the drone measure that altitude? Is it getting it from GPS, referencing a database of known locations and ground elevation? Is it measuring it with a down-looking sensor? I'm pretty sure it's not an altimeter, because those require calibration with a known nearby pressure reading (except above FL180, where a standard setting is used).
This brings me to my next question: If I program a waypoint flight and assign altitudes to the waypoints, are those altitudes AGL? Or relative to the Home point?
Example: Near a lake, my Home point will be on land, about 100 feet above lake level. I want the drone to fly out over the lake, descend to about 50 feet above the lake near a shoreline point of interest, photograph it, and return. What altitudes should I assign at the various locations?
After learning the basics on completely flat ground, I'm soon going to be flying in an area of variable elevation. I know as a Private pilot that there are two kinds of altitude, and it is vitally important to know which kind you, or a map, or controllers, are referring to: AGL (above ground level) or MSL (above mean sea level, measured by altimeter).
So when I am flying my Mavic 2 Pro, and it says I am 100 feet high, how is that measured? Relative to the ground below the drone? (And how does it do that?) Relative to Home? If it's the latter, doesn't that mean that in certain circumstances your altitude might be a negative number — if you launch from a mountaintop and fly down slope?
No, that wouldn't make sense. It has to be AGL. So if I launch at a mountain top and fly away from the mountain without changing relative altitude, the altitude reading would nonetheless rise, relative to the ground receding below — right?
And how does the drone measure that altitude? Is it getting it from GPS, referencing a database of known locations and ground elevation? Is it measuring it with a down-looking sensor? I'm pretty sure it's not an altimeter, because those require calibration with a known nearby pressure reading (except above FL180, where a standard setting is used).
This brings me to my next question: If I program a waypoint flight and assign altitudes to the waypoints, are those altitudes AGL? Or relative to the Home point?
Example: Near a lake, my Home point will be on land, about 100 feet above lake level. I want the drone to fly out over the lake, descend to about 50 feet above the lake near a shoreline point of interest, photograph it, and return. What altitudes should I assign at the various locations?
