M2P flying low over water

[boblui]

A bit bored today. Went out to test whether the VPS sensors of M2P can enable the altitude to be maintained when the craft is cruising over water . The result is positive. Despite repetitive full throttle down input has been applied momentarily ( < 1 sec ), the craft never went lower than 1 meter above the water surface. Those who still believe that VPS should be turned off when flying over water may want to rethink. I definitely will leave them on at all time.

 

[crlmjohnson]

that was good. but try it when it is a clear day, and very shinny outside.

good flying. I have flown over water several times. the drone do act a little different when it is a very clear day outside with the sensors on.

 

[boblui]

... the drone do act a little different when it is a very clear day outside with the sensors on.

In what way it act differently ?

So far what I have found is that if the water surface is choppy, the craft will hold a height of 0.5 meter above the water surface. Over very calm water, the holding height will be 1 meter as shown in the footage above. If the water surface changes from choppy to calm, the drone will actually ascend automatically from 0.5 meter to 1 meter. My feeling is that if the 3D camera at the belly cannot see any discernible patterns, the drone will stay further away from the surface below just to play safe. The same result is obtained after covering the camera with tapes.

 

[crlmjohnson]

one time I was hovering low over clear water, on a very clear, shiny day, and my drone started displaying those read prompts, about lighting, I figure it was because of he reflections from the water to the bottom sensors, all I did was rise the drone higher, and the red prompts stopped displaying. i had remember reading in one of the other forums about how to flying over low water. so I have made it a habit about flying about 30 feet over water, especially when I am flying at great distances between me and the drone.

 

[boblui]

... read prompts, about lighting ....

Do you have any pictures ? I have never come across anything like that

 

[boblui]

If you are referring to this one then it's really weird

 

[crlmjohnson]

no....sorry...that was last year (summer) when i was flying up over lake Michigan (vacation). since then i have not experience that. I have flown over a river here in Indiana around a small island. the water was not as clear as lake Michigan. and a few other rivers since then. Just that one time, it was my first time over water that I experience that. also it was very windy, that day.

I usually see that prompt you are talking about at night. especially when I fly over my drone pad:

 

[crlmjohnson]

This is where i got my information from when it came to flying over water:

DJI Guides - DJI Store (United States)

Online shopping for a great selection of at the official DJI Online Store.

store.dji.com

*Beginner pilots should refrain from flying over water at any time.

Disable Vision Positioning System (VPS)
All DJI drones come equipped with VPS, a technology that maps the surface below to help position the drone. When flying over water, however, light reflecting off of the surface can cause issues with this technology. Because of this, it’s best to maintain a height of at least two meters above the water. If you have to fly below this height for a special shot, we recommend you turn off the VPS to avoid any unstable actions by the drone. Caution: When you disable the VPS of your aircraft and the distance between water surface and drone is smaller than 2 meters, you should fly the drone with a low speed in your FOV (field of view). Also, the height needs to be adjusted frequently since the aircraft could possibly drift downwards. Be aware that the minimum height has to be above 1 meter when flying over water.

 

[Not A Speck Of Cereal]

VPS or not, the closer I get to the water, the more I want to keep my eye on the aircraft and totally ignore the screen. If I need to look at the screen, I raise the craft up by a meter or three first.

 

[boblui]

This is where i got my information from when it came to flying over water:

DJI Guides - DJI Store (United States)

Online shopping for a great selection of at the official DJI Online Store.

store.dji.com

*Beginner pilots should refrain from flying over water at any time.

Disable Vision Positioning System (VPS)
All DJI drones come equipped with VPS, a technology that maps the surface below to help position the drone. When flying over water, however, light reflecting off of the surface can cause issues with this technology. Because of this, it’s best to maintain a height of at least two meters above the water. If you have to fly below this height for a special shot, we recommend you turn off the VPS to avoid any unstable actions by the drone. Caution: When you disable the VPS of your aircraft and the distance between water surface and drone is smaller than 2 meters, you should fly the drone with a low speed in your FOV (field of view). Also, the height needs to be adjusted frequently since the aircraft could possibly drift downwards. Be aware that the minimum height has to be above 1 meter when flying over water.

Yes, I have come across this also. Base on my experience with the M2P, I am convinced that this is for older DJI models or firmware which may have different design. Unless there is substantiated reports ( ie, proven by flight logs ) on drones descending into the water by itself because of VPS sensors being turned on, I will not turn VPS off in any circumstances.

 

[boblui]

VPS or not, the closer I get to the water, the more I want to keep my eye on the aircraft and totally ignore the screen. If I need to look at the screen, I raise the craft up by a meter or three first.

In this case the drone was 400 meters away . I have done quite a lot of tests to ensure that I know how these sensors work before attempting the flight so I was fully comfortable with relying solely on the video feed.

 

[Phantomrain.org]

In this case the drone was 400 meters away . I have done quite a lot of tests to ensure that I know how these sensors work before attempting the flight so I was fully comfortable with relying solely on the video feed.

Its not that the sensors dont work as they do, what many have found out is that the VPS can become confused.
When this happens the drone can start to land, or just freeze in place as it tries to sort out what it needs to do.

If your flying over the water this can be an end of life event. when battery life is low or when landing in the water.

When we land on the Water you can see the VPS getting confused , Wave comes up to the drone it wants to land, Wave Drops away from the Drone and it pops back up and the cycle restarts.

Reflections can also cause some confusion to the drone.

This is why its best to just to Disable the VPS so no surprises as the sensors work well but can become confused.

Phantomrain.org
Gear to fly your Air 2 in the rain and float on water.

 

[boblui]

VPS can become confused.....

Not sure if drone pilots got confused or the VPS sensors do .... I have heard about this "confusion theory" many times but nobody can explain how such "confusion" can lead to drone descending into the water.

..... Wave comes up to the drone it wants to land, Wave Drops away from the Drone and it pops back up and the cycle restarts....

I don't know other drones but the M2 and Mini certainly do NOT do that. You don't need to fly over the water to test it. Just let the drone hover in front of you. Put a board beneath the drone and move it up and down. Will the drone react ?

The answer is NO with the exception that if you move the board too close ( < 30 cm ) to the drone, it will go up to avoid it. Otherwise it will just maintain it's altitude and do nothing. The behaviour over water surface is just exactly the same.