Altitude Warning

[SkyTime 3]

I was flying my Air 2S up a mountain pass in Oregon,at about 2,500 feet. I wanted to get above a hill so I could get a shot of a snow-covered peak, and I got a warning on my smart controller that I had exceeded to 400ft altitude limit. It told me I was 1,300 feet up, and Im pretty sure that wasn't true. But, the big red warning stayed on the screen, and I was afraid to do anything else so I brought it home. Doesn't the aircraft look at it's starting altitude and go from there? I'm a new user and confused!

 

[Deleted member 103366]

All heights are measured, by barometer so some discrepancies creep in, relative to the take off point.
If you took off, the zero of indicated height, from the base of the hill and flew to a point that was 500ft above the take off point but only 100ft above the ground beneath the drone, the app is still going to warn you you are exceeding 400ft above the take off point. The drone has no knowledge of its height above the ground beneath the drone. Height above the ground beneath the drone os often referred to as AGL.
Incidentally in most jurisdictions and instances a drone should be kept within 400ft AGL.

 

[Kywon McCain]

Fix your max alt. With a warning you can set it above 400ft

 

[eEridani]

If the aircraft was telling you it was 1,300 feet up: where you launched the drone being 0 feet, and the drone was 1,300 feet higher in the air column.

ps: The onboard IMU is pretty accurate, usually within a few feet over a typical 20 minute flight.

 

[PVilardi]

The fact that you were on a mountain pass is going to affect the way your drone reports your altitude. since the drone uses barometric pressure to determine altitude and the pressures are different on a mountain pass (assuming you were at some altitude on the pass) your reported altitude will be off.

 

[Deleted member 103366]

The fact that you were on a mountain pass is going to affect the way your drone reports your altitude. since the drone uses barometric pressure to determine altitude and the pressures are different on a mountain pass (assuming you were at some altitude on the pass) your reported altitude will be off.

Sorry but that is incorrect, the height above sea level (MSL) is irrelevant in terms of the height displayed in the app.
Where MSL does come into play is in that the air density generally decreases with height and at some height the air will become too thin for the drone to fly i.e. the motors will be unable to produce enough thrust.
I think some drones can detect this and issue an appropriate warning but the numerical value of MSL is NOT indicated in the normal height telemetry displayed in the app.

 

[Meta4]

I was flying my Air 2S up a mountain pass in Oregon,at about 2,500 feet. I wanted to get above a hill so I could get a shot of a snow-covered peak, and I got a warning on my smart controller that I had exceeded to 400ft altitude limit. It told me I was 1,300 feet up, and Im pretty sure that wasn't true. But, the big red warning stayed on the screen, and I was afraid to do anything else so I brought it home. Doesn't the aircraft look at it's starting altitude and go from there? I'm a new user and confused!

Yes, the drone starts at zero ft, wherever you launch from.
If the indicated on your screen showed 1300 ft, the drone would have been 1300 ft higher than where it was launched.

 

[Rabber]

All heights are measured, by barometer so some discrepancies creep in, relative to the take off point.
If you took off, the zero of indicated height, from the base of the hill and flew to a point that was 500ft above the take off point but only 100ft above the ground beneath the drone, the app is still going to warn you you are exceeding 400ft above the take off point. The drone has no knowledge of its height above the ground beneath the drone. Height above the ground beneath the drone os often referred to as AGL.
Incidentally in most jurisdictions and instances a drone should be kept within 400ft AGL.

I was flying my Air 2S up a mountain pass in Oregon,at about 2,500 feet. I wanted to get above a hill so I could get a shot of a snow-covered peak, and I got a warning on my smart controller that I had exceeded to 400ft altitude limit. It told me I was 1,300 feet up, and Im pretty sure that wasn't true. But, the big red warning stayed on the screen, and I was afraid to do anything else so I brought it home. Doesn't the aircraft look at it's starting altitude and go from there? I'm a new user and confused!

The barometer is zeroed at launch, so the display simply shows the drone's altitude above the point at which you launched. In addition, the altitude is calculated by an on board barometer that detects pressure and measures the difference from when it was launched to where it is now.

If you are on a mountain 1500 feet up from sea level, your drone will display 0 feet at take off.

 

[NewAir2sMan]

So inotherwords just reset your home point to where you were currently at when you got the warning and all would be fine.

 

[Deleted member 103366]

So inotherwords just reset your home point to where you were currently at when you got the warning and all would be fine.

NO, that does not work, it has been tried.
The work around is to land at height, allow the motors to stop then restart them and start a second flight but there are risks entailed in that.

 

[NewAir2sMan]

NO, that does not work, it has been tried.
The work around is to land at height, allow the motors to stop then restart them and start a second flight but there are risks entailed in that.

Well I mean of course land first, hit update, then off you go, no?

 

[BigAl07]

Well I mean of course land first, hit update, then off you go, no?

You have to stop/start the motors reset the ALT.

 

[NewAir2sMan]

Well I learned something new today then

 

[Deleted member 103366]

Well I mean of course land first, hit update, then off you go, no?

No, where you land, stop and restart the motor there is no need to "hit update". The homepoint and height, both new, are automatically set in the process, it is not a "reset" as such.
Resetting more often than not refers to changing the homepoint with the drone in flight.

 

[NewAir2sMan]

No, where you land, stop and restart the motor there is no need to "hit update". The homepoint and height, both new, are automatically set in the process, it is not a "reset" as such.
Resetting more often than not refers to changing the homepoint with the drone in flight.

So, technically I am correct. It's just that there's an easier way than I was aware of to accomplish the task?

 

[Deleted member 103366]

With regards to your meaning land, stop and restart the motors, take off, yes that process will reset both the homepoint and the height and yes your meaning was correct.
But with regards to what you actually wrote i.e. "hit update, then off you go" then I would venture that that was not correct as it is not necessary. Besides which, going by the light flashes I see, (I am deaf so hear no messages) the drone sets or resets the homepoint as it takes of or just after it takes off and that occurs even if it had set the homepoint whist on the ground.

 

[NewAir2sMan]

Ok thats all I wondered, just so long as I wasn't giving out completely wrong or bad info thanks

 

[Deleted member 103366]

You have to stop/start the motors reset the ALT.

Its a bit of an academic point since, for most folks a stop/start wilI be preceded by a landing and not many are as daft as me, but it is possible that landing (or the drone being stationary) may be a necessary part of the process.
I did a deliberate mid air stop and restart with a Phantom 3 and the heights in the DAT and both .txt's are all relative to the original take off point. I haven't yet got up the courage to try it with a Mavic of any sort.
The homepoint was however reset to the line of fall and that gave me the ibbey jeebies for a couple of seconds when, some time later, I pressed the RTH button, the line of fall was over 'deep sea'.