Question about elevation control

[kirbinster]

How does the Phantom control its elevation as terrain changes? What I am asking is does it maintain a certain height versus sea level or does it maintain its height to maintain a distance from the ground. Perhaps an example of what I am thinking about will make my question more straight forward. The street in front of my house is 700 feet elevation. The street goes up to the right of my house and climbs to about 900 feet. If I takeoff in front of my house and have the bird rise to 100 feet what will happen if I tell it to fly to the right following the street? Will it stay 100 feet over the road the entire way, or will it gradually get closer to the road and hit the ground as it gets halfway where there elevation is 800 feet above sea level?

 

[Brettly]

How does the Phantom control its elevation as terrain changes? What I am asking is does it maintain a certain height versus sea level or does it maintain its height to maintain a distance from the ground. Perhaps an example of what I am thinking about will make my question more straight forward. The street in front of my house is 700 feet elevation. The street goes up to the right of my house and climbs to about 900 feet. If I takeoff in front of my house and have the bird rise to 100 feet what will happen if I tell it to fly to the right following the street? Will it stay 100 feet over the road the entire way, or will it gradually get closer to the road and hit the ground as it gets halfway where there elevation is 800 feet above sea level?

It would hit the ground..same with mountain, trees, buildings etc..you would have to lift its elevation above the road, and you would see its altitude reading through the dji app and FPV.

 

[kirbinster]

So if I understand what you are saying it will maintain its altitude relative to sea level not the actually terrain. Is that correct?

 

[SpikeFinch]

So if I understand what you are saying it will maintain its altitude relative to sea level not the actually terrain. Is that correct?

Correct

 

[Brettly]

It maintains its altitude relative to its home point setting. If you started at 700ft and set its home point(or lock) at that spot, that's its relative location. Doesn't have to be terrain..u can launch from a roof, boat, car, helicopter etc

 

[Meta4]

The Phantom can't tell what is under it. That's your job.
It's take off point is the only point it knows and it considers that altitude as zero.

 

[N017RW]

I read the OP's question a bit differently...

The Phantom does not maintain altitude per se.
It maintains attitude, i.e. level, and does not know anything about varying ground level (terrain) underneath it and will not follow it.

As other have said the home point take off elevation [Z] is used for OSD display only.
The home point X-Y can be manually reset in flight but this does not change the OSD elevation reference.
Touch-down during RTH or auto-land is governed by pressure altitude changes. Once the landing has begun the a/c will descend until no more [pressure] change is detected. Thus the a/c will not fall from the sky or crash into the ground if the terrain level has changed since take-off.