I can't take off unless the home point it established by GPS. Typically a smart feature, I'm sure.

But what happens if someone wants to fly indoors, for instance in a warehouse?

Is this a new feature? I don't remember being grounded with 'cannot take off' in the past.

Are you certain that's how it is?
You can't take off until things have warmed up  and the Phantom is ready to fly but you can take off after that and before GPS has a good fix.

What you describe is how it always seemed to me. But after I updated everything recently I was getting a lot of 'cannot take off' messages, especially if I was indoors messing around or outside under trees where gps signal was slow to lock on.

Finally I seemed to trace it to the initial satellite locks. It will not allow motors to turn on until ~7 or 8 satellites lock. In these conditions that may take some time. Much more than just warming up.

The 'cannot take off' notice goes away immediately when the 'home point location set' message sounds. This all coincides with getting enough satellites, so it may not exactly be the home point being set that is a requirement, but some sufficient amount of satellites that also allows the home point to be set, if that makes sense.

This happens in any mode, even ATTI where GPS is not used.

So my question is, what happens if a person is in a location such as a metal warehouse where GPS may not ever be available? Just cannot fly at all?

Has the app defaulted back to Beginner's Mode? You can't take off in Beginner's mode without GPS lock.

CannotTakeOff Posted at 2017-5-5 20:31
What you describe is how it always seemed to me. But after I updated everything recently I was getting a lot of 'cannot take off' messages, especially if I was indoors messing around or outside under trees where gps signal was slow to lock on.

Finally I seemed to trace it to the initial satellite locks. It will not allow motors to turn on until ~7 or 8 satellites lock. In these conditions that may take some time. Much more than just warming up.

You should NOT be flying in a metal warehouse. DRONE AND METALS DON'T MIX and will screw up your compass big time.

CannotTakeOff Posted at 2017-5-5 20:31
What you describe is how it always seemed to me. But after I updated everything recently I was getting a lot of 'cannot take off' messages, especially if I was indoors messing around or outside under trees where gps signal was slow to lock on.

Finally I seemed to trace it to the initial satellite locks. It will not allow motors to turn on until ~7 or 8 satellites lock. In these conditions that may take some time. Much more than just warming up.

You should watch the screen closely to see the stage that you've missed.
At first the app displays Cannot Take Off (Atti) as the IMU is warming up.
Then it shows Ready to Go (Vision) before it gets a GPS fix.
At this stage you can launch without GPS either outdoors before a GPS fix or when in an areqa where there will be no GPS (indoors, forest, canyon etc)
The final stage comes after A good GPS fix - Ready t Go (GPS)