Today I had to  make the first flight  and I get the following error as  if the sensors  are disabled, but the  sensors are ok and activated, I  did sensors  calibration but I keep the  writing cannot take off Even if I  have 11 satellites, but do not the engines what do?  Yesterday  when I opened the box for the first  time the engines armed  them, then  after the upgrades made and  succeeded this, I tried to go  back in the  version but did not change  anything, I reset the factory  but nothing  goes wrong.

Are your batteries correctly inserted?

The visual sensors will always display that warning message until the landing gear is raised after takeoff..  

I only have one battery and dead, but in the instructions can I fly with one such and written or wrong?

I think that after the first firmware update you need both batteries to take off.

There is a thread on this a while back but basically to avoid battery problems always fly with two fully charged batteries.

You can Hot-Swap them mid operation, this is also mentioned in a previous post.

Make sure all your batteries are fully charged before a flight and things should work as planned.

The warning message always shows up when the landing gear is down, You will notice every time you come in for a landing, when you lower the gear, the message will pop up.