Launch from a moving ship?

Vaisraitor · Mar 6, 2018

Aha... Sorry misunderstood you. But no compass in the world tells you where north is [emoji14] Magmatic compass is pointing to magmatic north, which isn't north and there are two errors named Variation an Deviation, if you add them to the bearing the compass is telling you than this is north. (Variation depends on you location on the globe, deviation is up to interference by metal objects) the ships compass is adjusted a bit but still not pointing to North. Same is for gyrocompass.. This one point to gyronorth and also here are two corrections named speedcorrection and instrumentcorrection. This compass is more accurate on the ship (maybe 1 or 2 degrees off) but not fitted in the mavic

Simmo · Mar 6, 2018

Yup! So QED. I'm right! Go fly!!!!

daisy-girl · Mar 6, 2018

Simmo said:
I'm sorry, those two jpegs came out too close together. Obviously the bottom one is Go 4.

So with DJI GO 4, if I set ME (the GPS on my device) as the Home Point, and I move from place to place, won't the aircraft return to me, provided there is a GPS signal, no matter where I am located?

Simmo · Mar 6, 2018

If you press ME, first, then RTH, yes. (forget Dynamic HP)

daisy-girl · Mar 6, 2018

Simmo said:
If you press ME, first, then RTH, yes. (forget Dynamic HP)

So if I set ME as the home point when I first launch, and then I move elsewhere, I would need to reset the home point to wherever I am? And Precision Landing is the only feature that I would lose as a result of resetting?

P.S. It's hard to imagine a situation in which I would want the Home Point to be continuously reset to wherever a subject other than myself wants to go with my drone.

Simmo · Mar 6, 2018

Hmmm. When you first launch, you need to set nothing, other than to check that "Home point has been recorded, please check it on the map..."

Then, YOU move, the AC is flying all over the place...... if you hit RTH, the AC will/should land where it took off from....where you WERE....

If your device is capable, and you have moved, you set the HP to ME, then hit RTH, the device will/should land at your present location...NOW...

People say doing downhill skiing, may use Active track to follow them down a slope, using Dynamic Homepoint, if they say fall, and request a RTH, the AC is going to be very close to them for its home point... Not 2 k's away up the mountain..where they started their run.... So DHP does have its uses in the right situation, for the right people.

corchard · Mar 6, 2018

Simmo said:
If you press ME, first, then RTH, yes. (forget Dynamic HP)

Real NOOB question. Embarrassingly NOOB, so laugh at my expense. What is ME in this context?

Reading the manual provided no obvious acronyms and my google skills failed me.

Simmo · Mar 6, 2018

corchard said:
Real NOOB question. Embarrassingly NOOB, so laugh at my expense. What is ME in this context?

Reading the manual provided no obvious acronyms and my google skills failed me.

All good Brother, the most embarrasing question, is the one never asked!
ME means, me.....you, I, them, him, her, me....ME ! set the thing to come back to me. ME!

corchard · Mar 6, 2018

Simmo said:
All good Brother, the most embarrasing question, is the one never asked!
ME means, me.....you, I, them, him, her, me....ME ! set the thing to come back to me. ME!

To translate to thumbs on device:
1) on phone, tap MC settings, then by home point setting, tap the icon "set home point to Remote controller"
2) press return to home button

nikkolaa · Mar 6, 2018

Hi guys,
I will just share my understanding and recent experiences.

First, dynamic homepoint, in my sense, is just a way to update regularly the homepoint to avoid flyaways. It is not allowing you to land on something not static, am I wrong?

Second, during all our trip in south africa the past two weeks, I had always the compass error, both in red, and never performed recalibration.
I did not have any trouble in flying it that way probably because I respected direct VLOS always and used to fly mainly in manual : I did not try any smart mode yet [emoji58]

Worth to note auto RTH has never been triggered, as RC disconnection during flight

Spy_Corfu · Mar 6, 2018

i fly my mavic pro and so far not yet the mavic air all the time from my speed boat. A couple of important things:
first you must disable the downward sensors so you can land it by hand when it comes back as there is no way in hell you can land it on a flat surface while the boat is at sea as it is constantly moving.
Second the dynamic home point is all good and well but not so accurate and if you are in middle of the ocean you better make sure you have plenty of battery to find your little boat in the middle of the ocean.. unless you have land or big boats near you etc then you can visual guide you drone back to the boat from your phones screen.
Make sure you use a shade for the mobile phone as under the sun you can not see ****. it is terrible.
even if you have temporarily compass error but lets you fly then once you are off the metal interference you should be ok.. just move it around and as a last resort just hold it with your hand to take off.
We are still waiting for the update to enable active track to follow the object while dynamically moving the home point to its current position as is possible with the mavic pro but not yet with the mavic air.. so for the moment you can not go very far with the boat.. the air will just stop.
i almost lost my drone last year filming a maxi 72 race.

Simmo · Mar 6, 2018

corchard said:
To translate to thumbs on device:
1) on phone, tap MC settings, then by home point setting, tap the icon "set home point to Remote controller"
2) press return to home button

A much quicker way is to swipe the screen right to left.

Vaisraitor · Mar 7, 2018

@Spy_Corfu you are probably right about this magmatic interference. I hope i can test it soon when conditions allow it. Taking of should not be a problem IF there is room on deck (no cargo) then I have 60x16meters of landing strip haha.. To all: i hope i can soon try to take off from a moving cargo vessel whilst at sea, preferably first at anchor but we are not at anchor that often.

LeMur · Mar 10, 2018

I would suggest firstly to try landing on moving object on terrain.

mikereed100 · Mar 10, 2018

I live aboard my sailboat and most of my flying is done from the boat. Launching while moving is easy, just make sure there are no obstructions. landing while moving is more challenging, but can be done if the obstacle avoidance is turned off. Keep in mind that if you are flying from a container ship you will likely be moving between 10 and 18 knots which really ups the ante.

I have mentioned this before, but bears repeating. On 3 separate occasions when launching while the boat was moving at 4-5 knots the motors shut off when the drone was about 1 foot above deck, causing it to drop into the deck. I have no idea what caused this and did not think to check the logs and can no longer find them, so it remains a mystery. DJI tech support was no help in this regard. I now only launch and retrieve when the boat is stopped, or very close to it.

Steve Reed · Mar 10, 2018

The speed of a moving ship more often than not will exceed the maximum speed of a Mavic Air. Thus the instant you take off it will be flying away, never to return. Kind of makes this discussion moot. So I would suggest making sure your name and address is on it and you attach a flotation device.

Dronedevices · Mar 10, 2018

Simmo said:
MrRobville, can I ask if your ship has an old school compass in the bridge? (I dont care if the ship is commanded via wheel, joystick or Google)....
Could you also stand on the deck, and get an accurate compass reading to navigate your 120 mtr long vessel?
If so, then personally, I would be flying my butt off.... Granted, you need to be confident with landing on a moving object...

Most large old school compasses have deviation correction spheres next to the compass to compensate.

Dronedevices · Mar 10, 2018

mikereed100 said:
I live aboard my sailboat and most of my flying is done from the boat. Launching while moving is easy, just make sure there are no obstructions. landing while moving is more challenging, but can be done if the obstacle avoidance is turned off. Keep in mind that if you are flying from a container ship you will likely be moving between 10 and 18 knots which really ups the ante.

I have mentioned this before, but bears repeating. On 3 separate occasions when launching while the boat was moving at 4-5 knots the motors shut off when the drone was about 1 foot above deck, causing it to drop into the deck. I have no idea what caused this and did not think to check the logs and can no longer find them, so it remains a mystery. DJI tech support was no help in this regard. I now only launch and retrieve when the boat is stopped, or very close to it.

I plan to do the same and was wondering if you had all the landing modes off and was the boat moving significantly up and down.

Vaisraitor · Mar 11, 2018

Yeah on board this container ship we sail about 15kts on average and if we have the current with is and no swell it can do 18kts. So far the weather or cargo did not allow me to take of. Like i said before also consider the wind speed. In de last few days we had head winds and side winds but i always add the windspeed to our speed over ground because that's the maximum combination let's say..

Magmatic interference will remain no matter where i calibrate. So I'll have to try and just launch it when we have some empty hatch so i can take of and more importantly, land the drone. I'll keep you all up to date

edit: for those unaware: 1 knot = 1,852 km/h = 1,158mph so 18kts = +/- 33,4kmh = +/- 20,8 mph

mikereed100 · Mar 11, 2018

Dronedevices said:
I plan to do the same and was wondering if you had all the landing modes off and was the boat moving significantly up and down.

Not sure what you mean by "landing modes" but when I fly from the boat I turn off the obstacle avoidance. In each case when the motors cut out the seas were dead flat. I have taken off and landed in fairly rough water with no problem from the motors, but landing is dicey with the boat gyrating.