Hi all,

Recently in  2 discussions.
- how to interpret a flightlog where the remote pilot pushed the sticks in CSC position.
- Hover stability and height control low over water....

In the CSC discusion the flightlog showed only 1 record, the very last record, with a CSC.
In the Hover stability discusion, all about wich sensors for horizontal stabilily and wich for height control.

FIRST discussion
What will happen do a DJI drone in CSC ??  [ time for tests and numbers in flightlogs! ]

First : 2 setings in the Advanced Safety Settings for CSC
- EMERGENCY ONLY   >> CSC will stop motors if DJI sofware is determine a 'emergency' *
- Anytime (Use with caution). >> will stop motors after 1.5 second. ALWAYS!

situation1:   So what if remote pilot CSC a drone with setting EMERGENCY ONLY ?  drone will descend and circling down.
situation2:   So what if remote pilot CSC a drone with setting ANYTIME?   Obvious, drone will stop motors and falling out if the sky.

In the charts you see a CSC in both situations.
Nice to know (i wasn`t aware of this)  that in ANYTIME drone will not power off completely (just motor stop),  plus in the flightlog for 1.5 seconds the CSC is registerd.
Ofcourse when there is not excactly at the same time a connection error at start of the CSC!
(after motor stop flightlog recording is stopped as well, same as in a normal flight/ landing)

Second discussion
Horizontal positioning by GPS, with some aid from the bottom vision sensor if within range.
Vertical height control by barometric sensor and....does the InfraRed height sensor aid this stability??
Flying low over water sometimes height control goes weird...i see often in such logs an intermittent or no signal on the IR sensor.
[ nice to know! that PhantomHelp CSV copy paste the last height into next records until sensor is measuring height again ]

Time for a another test....

I tested my MINI2 flying low above grass, vision sensor duct taped : could not see difference to flying without covering the vision sensor (need to do it again few times)
Tested with vision sensor and IR sensor duct taped. OMG, see the height control performance in the video and in the chart!



Happy many landings, [ hope that you understand my chinese english  :-)  ]
cheers
JJB    [ Charts by FRAP ; the 'best' software for flightlog analysis ]

So, what is your recommendation for flying over water at low height?

Very nice test JJB*.  Thanks for sharing your results.  I live on a large boat so I'm going to continue to fly over water, just not super low.  I keep CSC set for Emergency Only.

A couple of points, the recording of the DAT continues after motor stop, though unfortunately with the Mini 2 that is of no use.
My experiments suggest the delay is 1.7 seconds not that the difference matters much, both delays are far too short for "Anytime" to be a safe setting.
An entertaining CSC video

LV_Forestry Posted at 4-11 11:22
So, what is your recommendation for flying over water at low height?

hi

my recommendation

1)  always keep your eye on the drone !  do not watch the screen
2)  be ready for UP stick any time

I fly a lot low and very low over water, guess only few times had to pull up quickly

Flying low over streaming water is 'killing' for the vision and infra red sensor!
Missing InfraRed height data has an effect on height control!

3) Don`t fly too low over streaming water, so you have more time to react to pull UP !


Have to do more test on the Vision part.
Hovering over streaming water : GPS keeps drone at the spot, Vision aids this and notice that the surface below is moving = drone is moving.  Seen drones drifing away on ths water flow...

cheers
JJB

JJB* Posted at 4-11 23:48
hi

my recommendation

Thank you, this test and these conclusions are very interesting. This confirms some things.

Try some indoor hovers but over two types of surface, one that is rock solid with nothing in the sensors' field of view that is flapping and the other were there is something, in the sensors' field of view, flapping.
I suspect the first one will produce a more stable hover, I think the sensors are sensitive enough to register "flapping" and respond to it.

Sean-bumble-bee Posted at 4-12 01:38
Try some indoor hovers but over two types of surface, one that is rock solid with nothing in the sensors' field of view that is flapping and the other were there is something, in the sensors' field of view, flapping.
I suspect the first one will produce a more stable hover, I think the sensors are sensitive enough to register "flapping" and respond to it.

Thinking of this

Hover over a well marked carpet, than pull this away under the hovering drone.
What will happen?

a) indoors with no GPS, so vision is there for horizontal stabity
b) outdoor with GPS lock,   how will the vision interfere with GPS positioning?

cheers
JJB

"Hover over a well marked carpet, than pull this away under the hovering drone.
What will happen?"

Actually at times I have seen the drone follow a distinctive 'INDOOR target' that was moved. This does not always happen and the target's movement was slow but it has happened for me occasionally.

With regards to "b) outdoor with GPS lock, how will the vision interfere with GPS positioning?" there have been threads that suggest the drone can, outside with GPS, track, over shortish distances, 'objects' that move in the sensors' field of view, these have mainly been over water.
Whether or not they are correct is hotly debated lol.
But when it comes to hovering with GPS AND VPS I think VPS greatly enhances the precision of the position holding. I have done low hovers at the same spot in daylight and at night and the daylight hovers have always been more stationary.
I suppose one could do a low hover at night with no light on the ground, take note of the drone's movement and then shine a good light on the ground and see if the movement diminishes.

Interesting to see / read!