DMX_MT
Second Officer
Malta
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JimFandango Posted at 2018-5-16 01:10
I understand that the Spark won't hold position in ATTI mode, but I wouldn't have thought the pause button uses GPS to use in its braking calculations because of the +/-5m or so horizontal resolution of the GPS. I was wondering, while in ATTI mode, which of the two options the Spark does:
1) Knowing that it won't hold position while stationary, the Spark ignores the pause button input; or
Hey Jim,
From the Video you can see that even with No Wind, if he pushes it, it will not Brake, and will drift away.
Its hard to tell if it is 1 or 2. I tell you why.
1) This is Most Probably how it works, but cannot Guarantee, only DJI Engineers can tell you about this, as we don't have any Documents Stating this Fact, but I think that how it works. Just like you said.
2) When in ATTI Mode it uses some Sensors + Barometer to determine the Height, I really doubt if it can calculate the Exact Speed, as there won't be GPS to make Distance Calculations, or some form of Laser Readings to Calculate Distance / Time Taken from Point A to Point B, correct me if I am wrong. If it calculated speed I dont know how it is done, maybe some form of Complex Accelerometers ?
In reality as far as I know, the Drone doesnt have Brakes. Just like a Ship or Boat. For a Ship to brake they usually think far before arriving and the engine rotation / motors will turn in reverse mode to cause the Braking.
The Drone just like the Boat, cannot Brake in the Air, as there is no Friction like when you brake a Car, Tyre with Tarmac Road. The Drone brakes in ATTI mode if you control it with reducing power and tilting backwards. Just like a Helicopter.
Imagine you have a Boat and I go to push it, it will still drift as the Sea is not a Solid Medium, just like Air, you cannot Grip or Grab the Air.
The GPS acts like an ANCHOR on a Boat -
Anchor - Holds the Boat in Position as it will have a Heavy Iron Anchor at the Bottom with a Chain Connected to the Boat. Still the Boat has no Brakes.
GPS - Holds the Drone in Position with Co-ordinates, if there is a force, by hand / wind etc.. if will force itself back to where it was Idle. Its like a Virtual Anchor done thanks to Co-ordinates of the Last Idle Point that the Drone Stopped. Its a bit complicated but when you see the Flight Logs you see that every Second is recorded as each Second there are lots of Computer Calculations being made inside the Drone. This is a Complicated Piece of Equipment.
If there was the Ability of having the Pause Button it would be GREAT, something could be done maybe a Bottom Camera which takes Images of the Ground Below it, and when the drone is in ATTI mode in Pause or Hover Mode, it will see that it is drifting (Change of Bottom Camera Images just like how a CCTV has Motion Detection) and will refer to the Pictures taken from the Bottom Camera to re adjust the position. This would be a problem on the Sea / Water though. Or Maybe a Field with Grass as the Background wont have so much different Textures. I know I am maybe saying a Stupidty. But just an idea.... Things start from little stupidities or mistakes eg. The Laser Hair Removal, where a Scientist burn his hand once and hair didn't grow again and left a patch.
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