Mini drifts when over water

[280]

I have noticed that when ever I fly over rapids or moving water my mini seems to start drifting around. Is that because of the sensors on the bottom? Is there anyway to prevent this? This issue has almost caused me to crash a few times and I would like to not have the worry of my mini uncontrollably drifting around when its hovering over water. This has caused me to lose some shots because I was too worried about my mini crashing into a tree near the water. Do other drones like the Air 2 have this issue?

Thanks
-280

 

[Yorkshire_Pud]

Outside, hover over something distinctive, not high, then slowly drag the something across the ground, does the drone follow?

 

[SethB]

What kind of altitudes above water are you flying when you experience this?

I have *NOT* tried it, but I know some people put a piece of tape over sensors, perhaps someone more experienced with this method will chime in. I’d explore it very cautiously

 

[Phantomrain.org]

Recommend you consider getting a Mini 2 wet suit that protects that sensor from getting confused. One of things that can happen to the mini 2 is when the sensors get confused it start to want to circle around as we have shown in our videos landing on the water.

We offer a nice package for the Forum Members.

Phantomrain.org
Gear to fly your Mini 2 in the Rain. an Around Water Falls.

 

[Meta4]

I have noticed that when ever I fly over rapids or moving water my mini seems to start drifting around. Is that because of the sensors on the bottom? Is there anyway to prevent this? This issue has almost caused me to crash a few times and I would like to not have the worry of my mini uncontrollably drifting around when its hovering over water. This has caused me to lose some shots because I was too worried about my mini crashing into a tree near the water.

The downward sensors will try to find something they can lock onto if the ground/water is less than 10 metres below the drone.
If what's below the drone is moving water, it can't help with horizontal position holding.
This is spelled out on p 16 of the manual.

The Vision System may not function properly when the aircraft is flying over water or snow-covered
areas

The Vision System cannot work properly over surfaces that do not have clear pattern variations. The Vision System cannot work properly in any of the following situations. Operate the aircraft cautiously.
a. Flying over monochrome surfaces (e.g., pure black, pure white, pure green).
b. Flying over highly reflective surfaces.
c. Flying over water or transparent surfaces.
d. Flying over moving surfaces or objects.
e. Flying in an area where the lighting changes frequently or drastically.
f. Flying over extremely dark (< 10 lux) or bright (> 40,000 lux) surfaces.
g. Flying over surfaces that strongly reflect or absorb infrared waves (e.g., mirrors).
h. Flying over surfaces without clear patterns or texture.
i. Flying over surfaces with repeating identical patterns or textures (e.g., tiles with the same design).
j. Flying over obstacles with small surface areas (e.g., tree branches)

Do other drones like the Air 2 have this issue?

It was possible to disable the downward sensors in some earlier models, but in recent Mavics DJI doesn't imclude that ability.
I'm not sure if it's possible with the new M3.

 

[Meta4]

Recommend you consider getting a Mini 2 wet suit that protects that sensor from getting confused.

Really???
How could that possibly work?

 

[280]

What kind of altitudes above water are you flying when you experience this?

I have *NOT* tried it, but I know some people put a piece of tape over sensors, perhaps someone more experienced with this method will chime in. I’d explore it very cautiously

I would say at least 15-20 feet above the ground.

The downward sensors will try to find something they can lock onto if the ground/water is less than 10 metres below the drone.
If what's below the drone is moving water, it can't help with horizontal position holding.
This is spelled out on p 16 of the manual.

The Vision System may not function properly when the aircraft is flying over water or snow-covered
areas

The Vision System cannot work properly over surfaces that do not have clear pattern variations. The Vision System cannot work properly in any of the following situations. Operate the aircraft cautiously.
a. Flying over monochrome surfaces (e.g., pure black, pure white, pure green).
b. Flying over highly reflective surfaces.
c. Flying over water or transparent surfaces.
d. Flying over moving surfaces or objects.
e. Flying in an area where the lighting changes frequently or drastically.
f. Flying over extremely dark (< 10 lux) or bright (> 40,000 lux) surfaces.
g. Flying over surfaces that strongly reflect or absorb infrared waves (e.g., mirrors).
h. Flying over surfaces without clear patterns or texture.
i. Flying over surfaces with repeating identical patterns or textures (e.g., tiles with the same design).
j. Flying over obstacles with small surface areas (e.g., tree branches)

It was possible to disable the downward sensors in some earlier models, but in recent Mavics DJI doesn't imclude that ability.
I'm not sure if it's possible with the new M3.

Thanks for the detailed reply! That makes sense.

Recommend you consider getting a Mini 2 wet suit that protects that sensor from getting confused. One of things that can happen to the mini 2 is when the sensors get confused it start to want to circle around as we have shown in our videos landing on the water.

We offer a nice package for the Forum Members.

Phantomrain.org
Gear to fly your Mini 2 in the Rain. an Around Water Falls.

How would that work?

 

[Phantomrain.org]

I am still trying to Crash the Mini 2 or at least video record some Reflection problems flying a few ft from the water but no luck yet to record a Crash do to Reflection.

However when the landing sensors get wet do to moisture / Rain drops /or mist or even snow flakes than we get some erratic circular motion on the Mini 2

This is where the Mini 2 Wet Suit Shines as it protects the landing Sensor on the bottom and its smooth sailing in the Rain and Snow and flying over water as well as handling reflection.

Windy so the camera blew over.

 

[Meta4]

This is where the Mini 2 Wet Suit Shines as it protects the landing Sensor on the bottom and its smooth sailing in the Rain and Snow and flying over water as well as handling reflection

Except that the problem has nothing to do with reflection or wet sensors

How would that work?

Not at all.

 

[Capt KO]

If you do block the sensor, there is no landing assist so it’s all on you. Be very careful when landing. My mini 1 would not hold elevation when hovering over water if below 20ft, would slowly descend. My Air2 does not have that problem but I use the Phantomrain Rescue Jacket, just in case. Well worth the investment if you enjoy water flights.

 

[280]

If you do block the sensor, there is no landing assist so it’s all on you. Be very careful when landing. My mini 1 would not hold elevation when hovering over water if below 20ft, would slowly descend. My Air2 does not have that problem but I use the Phantomrain Rescue Jacket, just in case. Well worth the investment if you enjoy water flights.

Would blocking the sensor solve the problem? Would it affect anything else? I am not worried about taking off and landing because I have a landing pad.

 

[Capt KO]

Would blocking the sensor solve the problem? Would it affect anything else? I am not worried about taking off and landing because I have a landing pad.

It would but you'll be depending on barometer only. No protection below so landing and low flying is all on you. Try it at home. If using Refresh, don't forget to remove the tape.

 

[Yorkshire_Pud]

Also you will have to control the landing speed, usually landing protection controls that.

 

[Zbip57]

Would blocking the sensor solve the problem? Would it affect anything else? I am not worried about taking off and landing because I have a landing pad.

There are two different types of sensors (three altogether).

The central vision sensor is a camera used to detect patterns on the ground. It is the one used to accurately hold position in hover if the GPS sensor is incapable (insufficient satellite reception).

The two outer infrared sensors are for height measurement. Those are the ones that trigger the automatic climb response if you hold your hand too close under the belly of the Mini, also the ones that prevent the Mini from descending too close to the ground unless you actively command a landing.

If you are concerned that moving water might cause your Mini to drift while hovering, you could try covering only the central vision sensor. I've never tried it myself, so you're on your own doing this test. Let us know what you find.

 

[280]

There are two different types of sensors (three altogether).

The central vision sensor is a camera used to detect patterns on the ground. It is the one used to accurately hold position in hover if the GPS sensor is incapable (insufficient satellite reception).

The two outer infrared sensors are for height measurement. Those are the ones that trigger the automatic climb response if you hold your hand too close under the belly of the Mini, also the ones that prevent the Mini from descending too close to the ground unless you actively command a landing.

If you are concerned that moving water might cause your Mini to drift while hovering, you could try covering only the central vision sensor. I've never tried it myself, so you're on your own doing this test. Let us know what you find.

View attachment 144488

I will experiment with this later this week. Thanks for the information!

 

[billiam1]

This explains very it well (from 17:50 onwards )

 

[280]

I just experimented and it almost ended in a fly away. I covered the 2 out side sensors but I guess it was still reading off of them because I lost all control. Thankfully I was in a controlled area and I had no GPS so the only thing it did was fly side ways until it hit a tree and crash landed. I think if I did have GPS it would have flown up and never stopped going up. I think I am done messing around with the sensors. Thankfully it only ended in some broken propellers.
Instead of messing with the sensors I will just upgrade to something better. I have been looking at the air 2. Would if still have this problem?

 

[Meta4]

I just experimented and it almost ended in a fly away. I covered the 2 out side sensors but I guess it was still reading off of them because I lost all control. Thankfully I was in a controlled area and I had no GPS so the only thing it did was fly side ways until it hit a tree and crash landed.

Your drone didn't fly away and the problem you encountered was not due to taping the downward sensors..
You were just surprised at the way it flew without GPS to give horizontal position holding.
It would have been like driving a car with no brakes.

I think if I did have GPS it would have flown up and never stopped going up.

Loss of GPS doesn't affect vertical position holding, which comes from a barometric sensor.

Instead of messing with the sensors I will just upgrade to something better. I have been looking at the air 2. Would if still have this problem?

Yes .. you still won't have the ability to disable downward sensors.

 

[Zbip57]

Slow down. That's just too confusing.

I just experimented and it almost ended in a fly away.

Almost? So then, not a fly away?

... you could try covering only the central vision sensor.

I covered the 2 out side sensors...

The two outer sensors are the infrared sensors that measure height.

I lost all control. Thankfully I was in a controlled area and I had no GPS so the only thing it did was fly side ways until it hit a tree and crash landed.

Why did you have no GPS when flying outside in an area with trees? Why would covering the infrared height sensors cause the drone to uncontrollably fly sideways?

In the absence of a good GPS lock, the drone will use the centre optical sensor to fix on a ground pattern. If that pattern is moving (ripples on water, long grass waving in the wind, etc), the drone may follow that moving pattern. But that only happens when the control sticks are centred and the drone is hovering. You still always have control input. It just won't automatically brake to a halt when the sticks are released. You need to manually input some reverse stick input to slow the drone to a stop.

If it can't detect a suitable pattern (too dark, too monochrome, etc), and no GPS lock, the drone will default to ATTI mode. That only means it cannot stop and hold a fixed position in hover whenever the control sticks are centred. It will be free to drift with the wind. But it will still react to any stick inputs.

I think if I did have GPS it would have flown up and never stopped going up.

Why would GPS cause it to fly up?

Covering the infrared height sensors might cause the drone to automatically climb. For example, with the drone hovering, if you bring your hand up underneath the drone the sensors will detect your hand and interpret itself as being below the minimum 2 ft height above ground. The drone will automatically rise up to avoid your hand.

Whenever there is anything closer than 2ft underneath the drone, the infrared height sensors will cause the drone to climb. People have reported such a reaction when flying in dense fog, or when trying to descend through a cloud. But the drone can be forced to descend through such fog by pulling the throttle all the way down. If the sensors interpret the drone as being within 2ft of a surface, holding the throttle down will trigger auto-landing. The drone will then automatically slowly descend through the cloud until touching down on a solid surface. You can cancel the auto-landing at any point when necessary.

 

[Phantomrain.org]

I think you would learn more about how the sensors work if you just flew at night , and to understand that GPS has nothing to do with any sensors. You just needed to wait for the home point to record as normal.

Phantomrain.org
Gear to fly your Mini 2 in the Rain/ Snow and land on the Water.