Start and take off from moving object e.g. ship (vessel)
2651 6 2019-1-16
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Salvagepeet
lvl.1
Flight distance : 780492 ft
United States
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Hi there all DJI fans!

My name is Peter, live in The Netherlands, and recently purchased the DJI Mavic 2 Zoom. One of many reasons I bought it is because of the type of work I'm doing (worldwide).
I work for a big Maritime Salvage Company called Smit Salvage and my work deserves it to make beautifull footage for the work I'm doing, Salvaging sunken ships, is beautifull too.
I bought the Mavic 2 Zoom on january 4th 2019 and flew several times in the last 10 days with it without any problem or issues whatsoever!
But since today I'm experiencing some issues with the Mavic from which I'm hoping somebody from the forum, or DJI/moderator/technician him/herself, can help me out with.
Thrutfully I have to inform you that at this moment I'm on a vessel (huge tugboat) sailing on the North Atlantic Ocean.
Here below my explaining of what I've encountered today when I tried the operate the Mavic and let her take-off from the aft deck of the vessel I'm on:
  

When all was switched on and connected to each other, the message to calibrate the compass popped up. This was done successfully and a GPS connection was established.
  
  
After the succesfull compass calibration and GPS connection, almost immediately the message 'calibrate IMU' and 'can not take off' popped up.
Just a few seconds later these messages disappeared but only to show up again a few seconds later. This continued over and over again and I was not able to start the engines.
  
  
At a certain moment, when the message to calibrate the IMU did not came back and the message 'ready to take-off' appeared, I was able to start the engines .
  
Almost immediately the Mavic moved a few inches by itself; I did not throttle up and the propellers were idle but also the message 'calibrate IMU' popped up again.
  
  
When the IMU calibration message disappeared again for a longer period I throttled up slowly and the drone immediately pulled up into a (backward) angle as if it wanted to return to its previous point of take-off, then overpulled itself and landed up-side down onto the wooden deck. NO damage whatsoever.
  
  
We stopped this trial to avoid it would end in a complete disaster.
  
  
After it was placed back on the wooden deck, we observed that the camera, for it was still switched on, was moving/reacting slowly on the movement and motion of the ship which was rolling and pitching several meters from left to right/up and down and had a speed of approx. 10-12 nautical miles per hour which is approx. 18-22km p/hr; the camera was apparently compensating the motion of the ships rolling and pitching.
  
  
Because of this I wanted to check something so I entered the Main Controler Setting >> Advanced Settings >> Sensors, and saw that the ACC1, ACC2, GYRO1 and GYRO2 went haywire; from green to yellow to red to green to red to yellow to red etc. etc. etc.. It was, at least to my believe, that due to the movement of the vessel (rolling, pitching and the present speed of 20+km per hour) the IMU could not keep up with all this mistaking and mixed up information.
  
  
So after above explanation of what happened, and my present circumstances, below my question(s):
  
1) Am I correct in my believes that the motion of the ship and its speed causes these error and IMU calibration readings?
  
2) Is it possible to switch-off curtain things (IMU or Compass or GPS) so I can take off anyway?
  
3) If not, can I, despite above mentioned circumstances, do something to take-off anyway?
  
4) Is it possible to take off with the Mavic 2 Zoom from any moving object?
  
  
The reason for the last question is that in a few days we will move to another ship which is moving slower (4-6km per hour max.) and has less rolling and pitching (almost zero).
  
  
I honestly hope you can help me out here for otherwise, at this moment, the drone is useless for us at this time to do why we have purchased it for.
Many thanks in advance for those whom can help me out here!!



2019-1-16
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Boffin
Second Officer
Australia
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Salvagepeet , you have a few problems in your scenario.

1. The IMU calibration would be impossible on a moving ship as it depends on a perfectly level and stable surface. Maybe if the IMU was calibrated back in port it would help.

2. The steel of your ship would mess seriously with the compass calibration. When you take off, once away from the steel of the ship the compass swings to true magnetic north and the IMU does not detect this heading change so there is a conflict and your Mavic 2 Zoom resorts to 'Atti mode' , dumps the GPS info so now you have to fly it home and land manually (on a moving ship).

All I can suggest is to fly your Mavic 2 Zoom on dry land and learn it's capabilities and limitations.

Sounds like a nice job btw
2019-1-16
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alexzark
lvl.2
Flight distance : 124081 ft
Russia
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You need Dynamic Home Point mode. All owners of Mavic are waiting for this mode from programmers. DJI promised back in September but ...
2019-1-16
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AlphaFlightNW
Second Officer
Flight distance : 784265 ft
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United States
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As mentioned, the steel of the ship can interfere with the IMU, thus causing issues. If possible, try hand launching by placing the thumb below the notch where the rear legs fold in. Very risky IMO but works. Just youtube it first before you get chopped, I almost did.
2019-1-21
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atercervus
Second Officer
Flight distance : 1084957 ft
Monaco
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alexzark Posted at 1-16 22:31
You need Dynamic Home Point mode. All owners of Mavic are waiting for this mode from programmers. DJI promised back in September but ...

Dynamic Home Point has nothing to do with the magnetic interference and freaking out IMU. Had some experience taking off from boats - it's always a disaster with Mavics. Less issues with Phantoms which you can lift over your head and launch from hands, as well as catch in hand, as landing a Mavic on a small moving boat is also a challenge.
2019-1-21
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atercervus
Second Officer
Flight distance : 1084957 ft
Monaco
Offline

alexzark Posted at 1-16 22:31
You need Dynamic Home Point mode. All owners of Mavic are waiting for this mode from programmers. DJI promised back in September but ...

Dynamic Home Point has nothing to do with the magnetic interference and freaking out IMU. Had some experience taking off from boats - it's always a disaster with Mavics. Less issues with Phantoms which you can lift over your head and launch from hands, as well as catch in hand, as landing a Mavic on a small moving boat is also a challenge.
2019-1-21
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Blellow
Second Officer
Flight distance : 1311056 ft
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United States
Online

Just launch it.  It will fix itself once in the air.  Be careful, it will fly irregularly until it fixes itself.
2019-1-21
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