Autopilot app question.

[MavicKhan]

As a pilot, I keep getting this feeling, in this hobby, that app developers mix heights with altitudes and vice-versa.

I am taking my first steps with Autopilot.

In this app, when inputing "Altitude" in a waypoint are we really selecting an altitude (i.e. measured vertical distance to mean sea level, adjusted for barometry) or simply "height"/"elevation", the vertical distance of an object measured from a specified datum? If it is the later, which datum reference is used at each point? The departure point as "0" or the ground elevation laying beneath, at that point.

The difference is crucial to avoid mishaps and I would appreciate any clarification on the subject.

Thanks.

MK

 

[Oyibo VFX]

It is the altitude measured from your start point.


Adventure is just bad planning

 

[MavicKhan]

You mean height or elevation measured from my start point?

(There's no such thing as "altitude from a starting point". That confusion is, precisely the point of my post)

...but, if so, how come the app does not allow for negatve values at the waypoints? How do you direct it to fly at lower level than that departure reference, say, departing from an high hill to film a lighthouse below, a coastline?

Thanks.

MK

 

[Oyibo VFX]

Autopilot does allow negative vallues.
And yes, height.... sorry


Adventure is just bad planning

 

[MavicKhan]

Autopilot does allow negative vallues.
And yes, height.... sorry


Adventure is just bad planning

Thanks,

I have this afternoon free and am undergoing accelerated-self-desk training on the app.

I have it here, right by my side, inputing a training waypoint mission and can't figure out how that is done.

No matter if in the "Basic", "Intermediate" or "Advanced" tabs, at each waypoint selection window the "Altitude" slider does not go below +8 meters.

MK

 

[Oyibo VFX]

I'm getting quite good at Autopilot. Make a Private Message and tell me your issue


Adventure is just bad planning

 

[cd419]

Autopilot can use two different methods for calculated Altitude.

The first is what is the default behavior of DJI GO which is the altitude is calculated based on the take off point as 0. Meaning if you take off at the base of a mountain and fly towards it the aircrafts actual AGL altitude will decrease but the altitude the Aircraft is reporting will stay the same.

The second method which I believe is unique to Autopilot is it will use the barometer reading of the pilots iOS device as a dynamic altitude reference. Meaning if you were to follow along on a mountain road beside the mavic as it flies it will maintain an altitude relative to your iOS device.

 

[Oyibo VFX]

That is correct but only if GPS reception fails (if I'm correct)


Adventure is just bad planning

 

[cd419]

Edit: GPS is used for altitude reference on your iOS device IF a barometer isn't present. GPS isn't nearly as accurate for Altitude readings so I recommend against using Dynamic altitude reference if your device is not equipped with a barometer. You choose between dynamic and take off point altitude reference when engaging Autopilot. Flight School - Autoflight Logic

GPS isn't used for altitude. It is strictly the barometer on the Mavic. The only thing that you are changing is how the mavic calculates its altitude relative to a zero point. In the dynamic example the zero point is being updated by the reading from an iOS device hence the need to calibrate the reading before using this method.


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[sdharris]

One thing to point out with Autopilot is before you engage for the first time it will ask you to select your altitude reference, that's using their term not the dictionary term ;-) This is crucial as it will define how the height is calculated by all flight modes until you power off or close the app. It'll ask you things like whether you are using a fixed point or a moving or dynamic point that may change altitude Flight School - Autoflight Logic.

If you get that right you are good. Get it wrong though and your height will always be off. For example, back in previous versions if you had the aircraft in the air about 100 feet up, then selected that as the reference, any altitude used from that point onwards would be 100 feet higher. Say for example you did an orbit 50 feet up, then it would fly to 150 feet and perform the orbit. This is less difficult to do nowadays as the interfaces is more refined, but does illustrate what can happen.

If I were you I would not do a waypoint as your first flight, do an orbit. Once you get comfortable try a zip line, then do waypoint mission, as a waypoint is just multiple ziplines. Gets you comfortable without losing sight of the Mavic.

 

[jerry2032]

I can't speak for Autopilot but as for DJI GO 4, one workaround I've found to orbit a point of interest below me is to fly over the POI, set the home point to that location, fly the aircraft to the spot you want to begin the orbit at, change the flight mode to Home Lock, and the pull the right stick to the lower left or lower right corner depending on which way you want to orbit the POI. You have to control the camera but it seems to work.

When you're done re-set the home location to your location.


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[MavicKhan]

I've read the "Flight School" and am appalled by the way they arbitrarily decided to call " Altitude" to something that simply is not.

Moving forward and keeping things simple...

Will someone be so kind as to elucidate me on the following simple scenario:

A waypont mission is to be built whereas the operator designates a starting point 30 feet above his position, with him standing on 100 feet high cliff. The second point is intended to be into the ocean, 50 feet below the cliff level.

How does one go about inserting that simple instruction with the "Altitude" slider in that 2nd point menu?

Thanks.

MK

 

[sdharris]

OK moving past your obsession with the altitude thing if you want to use negative values you need to change the default minimum height setting under settings | movement parameters. Once set to a negative value you can specify waypoint altitude below the reference point.

So your first waypoint will have an altitude of +30, your second would be -50 and when you engage ensure you set the take off location or the operator as the reference point assuming you and the Mavic Pro are standing on top the 100 flight cliff and do not intend on moving if you use the operator.

However, the above is pretty advanced and as you say you are taking your first steps. So don't do this until you are 100% happy with the use of the app. Like I say, start with orbits and ziplines and practise disengaging either in app or by switching flight modes.

Have to say I have never used negative values, I always use the default minimum altitudes and start from the ground up. Finally there is always more than one way to skin a cat so you may find other ways to do the above, thats the fun of it!

 

[MavicKhan]

OK moving past your obsession with the altitude thing if you want to use negative values you need to change the default minimum height setting under settings | movement parameters. Once set to a negative value you can specify waypoint altitude below the reference point.

So your first waypoint will have an altitude of +30, your second would be -50 and when you engage ensure you set the take off location or the operator as the reference point assuming you and the Mavic Pro are standing on top the 100 flight cliff and do not intend on moving if you use the operator.

However, the above is pretty advanced and as you say you are taking your first steps. So don't do this until you are 100% happy with the use of the app. Like I say, start with orbits and ziplines and practise disengaging either in app or by switching flight modes.

Have to say I have never used negative values, I always use the default minimum altitudes and start from the ground up. Finally there is always more than one way to skin a cat so you may find other ways to do the above, thats the fun of it!

Thank you for your in-depth reply. Much appreciated.

My "obsession" stems from almost 40 years as an aviator, first as a fighter pilot with an ejection under my belt, then as airline F/o, Captain and former TRI who has repeatedly committed himself to make sure that the concepts associated with these definitions were made clear, in order to make the skies safe for everybody.

For all practical purposes UAV are flying machines that have to comply with provisions set out by such authorities as the FAA and EASA.

As such, it is not up to manufacturers or software developers to come along with personal definitions for long established aeronautical terms and concepts. Not obeying to a defined lexicon for a particular activity can lead to unwanted results, and, in aviation's particular case, those results can be nasty.

I've now come to conclusion that Auto Flights's Autopilot is not very effective in this regard.

I've also downloaded Litchi and, the simple fact that it has a desktop planning tool - "Mission Hub" - where any created waypoint immediately shows overall elevation and height difference from the starting point, makes it a more adequate approach for my needs.

I will keep AF Autopilot and will certainly explore it in depth in the future but, for the moment, I will train with Litchi to make it the tool of choice for my next project.

Again, thank you so much for your help and I hope I can keep counting on you guys in the future to help me better understand Autopilot.

MK

 

[sdharris]

Interesting that you prefer Litchi, I have used both for a couple of years and consider Litchi to offer only about 50% of what Autopilot does, Autopilot just has the steeper learning curve. You can also define a flight on an iPad and save it, loading it again on an iPhone if you prefer to conduct the flight. I find that more than makes up for the lack of a mission hub which is a pain to use.

Good luck with whatever tool to decide to use and look forward to seeing the results of that cliff flight!

 

[Oyibo VFX]

No problem with negative values

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