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Flying over water -- are all the drones the same?

What that flight video made clear is the rescue jacket and pontoons eat 50% of your battery life: 11.5 minute flight duration to 9% instead of 30 minutes (ahem, 17 minutes actual for most of my flights).
 
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From what I was told certain types of sensors are unable to detect water, so if you have to emergency land, the water is not a solid surface, so it goes through the water in an attempt to land on the solid beneath… In other words, goodbye drone.
With visual and IR sensors, it likely isn't so much the water as it is too much like trying to land on a mirror.
 
The altitude data for all DJI drones comes from a barometric sensor that maesures air pressure changes.
It's common and normal for the indicated altitude to change 10 feet or more during the course of a flight.
It has nothing to do with whatever is below the drone.

They are basically the same.
Do not trust your indicated height to display accurate height.
You need to allow some margin for error.

The MA2 (an the A2S I would imagine) use sonar for altitude up to 12.3 meters (~40 ft). If you look at your altitude data in AirData, there are 2 columns for altitude...one is sonar and the other barometric. Once the altitude reaches 12.3 meters, it doesn't change. At that point, presumably the barometric sensor takes over.

So altitude issues that are below ~40 feet shouldn't be impacted by barometric variations.

UPDATE - looking quickly at flight data I see the where the sonar altitude maxes out varies from flight to flight. I've seen it as high as 15m and as low as 6m. No explanation for that.
 
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The MA2 (an the A2S I would imagine) use sonar for altitude up to 12.3 meters (~40 ft). If you look at your altitude data in AirData, there are 2 columns for altitude...one is sonar and the other barometric. Once the altitude reaches 12.3 meters, it doesn't change. At that point, presumably the barometric sensor takes over.

So altitude issues that are below ~40 feet shouldn't be impacted by barometric variations.

UPDATE - looking quickly at flight data I see the where the sonar altitude maxes out varies from flight to flight. I've seen it as high as 15m and as low as 6m. No explanation for that.
Quite sure your SONAR is actually the IR sensor height. AirData is just wrong about that.
 
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(Mod Removed)..You deserved to lose it. So it was in visual line of sight all the way was it??
The video was sent in from a Client Testing out the Rescue Jacket in a long distance Flight .
The client is known for long distance flights using his family as the spotters .. In this case he flew the drone to 39 % before making it back> No drone was lost ,

Phantomrain.org
Gear to fly in the Rain. Land on the Water.
 
So altitude issues that are below ~40 feet shouldn't be impacted by barometric variations.
The primary source of altitude data is still the barometer.
In the DJI Fly app, there is no display of the VPS sensor height data.
 
I live near saltwater and almost directly on a marsh with a channel running through it, and I've seen a lot of warnings about flying over water. It has to do with the drone' ability to interpret the reflections from the water, I think. When I checked the DJI site, there is a specific warning not to fly the Mavic Air 2 (my model) over water, but the same warning didn't appear for the Mavic Air 2S. Which is why I wonder if the drones' sensors are the same on both models.

Since I like to video family, friends, and neighbors kayaking and boating, it worries me. I try to keep the drone over the marsh grass to make sure it has something to see but I'm not sure how much the view of the grass helps. Hopefully a lot. I've attached a pic to show the area I'm talking about. If links are allowed on this forum you can see a video here:
I have flown my MA2 over several forms of water: rivers, lakes, and the ocean. I find it doesn't have trouble flying over anything with the exception of flying very low over perfectly still water. I come across this problem trying to take shots over beaver ponds around my house. It doesn't fly away or anything but I get alarms about it not being able to detect hazards and the like. I am aware of what the manual says, so I am always a little more careful when flying over still water at a low altitude. Basically, if the water is more like a mirror, the MA2 can't see it that well and it doesn't seem to like flying blind. But flying over choppy waves in the ocean, the Columbia River (it's big), or a moving creek or stream...it has no issue from my experience.
 
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This is a topic of constant myth and misinformation.
The sensors are used to provide horizontal position holding at low altitudes.
They have difficulty locking on to the water surface, just like they can on dry land with surfaces that lack suitable texture or patterns.
But that only affects horizontal position holding at low altitudes.
It has nothing to do with vertical position ( altitude) holding.
Do whatever you like over water.
Just don't fly into the water, just as you don't want to fly into the ground.

Much of that isn't true and you're just adding to the misinformation ... again.

The bottom visual sensors are also used for downward collision avoidance. I have MANY times had my drone (MA2) warn me (beeps) that I was too close to some object, such as a tree, rock, deck of my house ... even tall grass. It had nothing to do with horizontal positioning, and it had nothing to do with whether I was moving or not. The drone won't even let me get close to those objects (vertically) unless I'm telling it to land.

Water causes some problems with that downward visual sensing. Reflections off ripples can give indeterminate feedback for distance, and infrared energy can penetrate the surface of calm water ... making the drone think it's further from the water than it actually is.

Water and ground isn't the same, no matter how many times you say it.
 
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I live near saltwater and almost directly on a marsh with a channel running through it, and I've seen a lot of warnings about flying over water. It has to do with the drone' ability to interpret the reflections from the water, I think. When I checked the DJI site, there is a specific warning not to fly the Mavic Air 2 (my model) over water, but the same warning didn't appear for the Mavic Air 2S. Which is why I wonder if the drones' sensors are the same on both models.

Since I like to video family, friends, and neighbors kayaking and boating, it worries me. I try to keep the drone over the marsh grass to make sure it has something to see but I'm not sure how much the view of the grass helps. Hopefully a lot. I've attached a pic to show the area I'm talking about. If links are allowed on this forum you can see a video here:
I fly my MA2 over water about 95% of the time. Most posts talk about 17’ altitude being the points by where the drone uses a down looking sensor. I have also read that most of the uses are when the water is still like glass. Waves are better and help the sensors. If you would like to check out any of my vids. They are at https://youtube.com/user/davidblezard
 
I fly my MA2 over water about 95% of the time. Most posts talk about 17’ altitude being the points by where the drone uses a down looking sensor. I have also read that most of the uses are when the water is still like glass. Waves are better and help the sensors. If you would like to check out any of my vids. They are at https://youtube.com/user/davidblezard

You sound like someone who knows what they're doing. Waves makes sense ... a little froth is reflective and not as quick (fluttery) as ripples.
 
The bottom visual sensors are also used for downward collision avoidance.

Water and ground isn't the same, no matter how many times you say it.
And what you are saying is misinformation, no matter how many times you push it.
Obstacle avoidance isn't the thing that so many are confused about with water.
It's some sort of failure to maintain altitude that's what so many are concerned about.
Your drone will maintain altitude as well over water as any other surface.
The alleged confusion of sensors, has nothing to do with maintaining altitude.
 
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And what you are saying is misinformation, no matter how many times you push it.
Obstacle avoidance isn't the thing that so many are confused about with water.
It's some sort of failure to maintain altitude that's what so many are concerned about.
Your drone will maintain altitude as well over water as any other surface.
The alleged confusion of sensors, has nothing to do with maintaining altitude.

You said that flying over water is the same as flying over land, with no need to be any more concerned about flying over water than over land. "Do whatever you want to over water", is what you said. You've stated that same thing several times on these forums and you've been wrong every time. It's not a failure to maintain altitude issue ... as several people have pointed out, maintaining a desired altitude is the job of the barometric sensor. Although the downward facing optical sensors certainly won't CAUSE a dip into the water, they aren't as dependable for preventing it over water as they are over land. There IS a difference.

You made another incorrect statement in your post when you said that the downward facing sensors need a pattern over land to function properly. They don't. They need a distinct pattern to provide more precise RTH landing, but for obstacle avoidance all they need is a stable reflection.

I'm certain that you're going to keep saying the same thing. I can only hope that others here will recoginize the difference.
 
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I'm certain that you're going to keep saying the same thing.
You are correct.
Having read your posts on the topic, I'll continue to safely fly over water without any more concern than I would over land.
Water is an obstacle, just like trees and the ground.
Drone flyers fly into obstacles all the time.
Whether they fly into the water, the ground or hit a tree, there's no mysterious force that causes that.
 
is your controller giving you verbal information? I can hear it muttering. My Mini2 only says a few things. Yours seems to be giving you constant verbal info. Is there something I can enable to get the same?
No, the client who made this video used Air Data to show the Information and another program called Dash to provide the display , and the Auditory Background was added extra.

Phantomrain.org
Gear to fly your Air 2 in the Rain.
 

Ha ha! I love some of the remarks in here.​

I am a recent convert to drones and flying them, I have a Mini 2 and love the little beastie.
I am still learning and expect to still be learning in 20 years time. (God willing)
I have read so much about flying over water, some say don't do it you will lose your drone! While other says it is perfectly alright to fly over water but keep a sensible height (Whatever that is).
I would hate to lose my little beast, but, I don't want to fly so cautiously that there is no excitement or a little danger involved.
I am in The United Kingdom, I have my CAA Pilots/Flyer ID and Operators Licence, I have £12,000,000 Public Liability Insurance, sounds excessive I know but the cost is £36 per annum, will certainly cover me for most mishaps on my part.

I purposely went out a found a small lake to try out flying over water and was amazed at the little Mini 2. The lake is a fly fishing lake and has a movable fountain on it to help keep the surface clear of debris.
I flew five feet over the top of the fountain, bearing in mind that the fountain is only 3 feet high, so I was about 8 feet off the surface water.
I hoovered over the fountain for about 3 minutes just 5 foot above the spray, the Mini2 held station vertically and deviated about 12 to 18 inches horizontally, at no point did it try to land, Maybe it would have done if I had brought it down another couple of feet.
This exercise has given me more confidence in the capabilities of this little beastie.
I did video the flight but not sure how to post it on here, (I will give it a go).
Nope just a comes up with a http://, not going down that route.
My video makes it look closer to the fountain than I actually was as I zoomed in. I was 8 - 9 feet max above the lake surface.

Manual/Pro, Cine Mode 1080p, 25 FPS & 50 Shutter Speed,16 ND filter.
 
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Ha ha! I love some of the remarks in here.​

I am a recent convert to drones and flying them, I have a Mini 2 and love the little beastie.
I am still learning and expect to still be learning in 20 years time. (God willing)
I have read so much about flying over water, some say don't do it you will lose your drone! While other says it is perfectly alright to fly over water but keep a sensible height (Whatever that is).
I would hate to lose my little beast, but, I don't want to fly so cautiously that there is no excitement or a little danger involved.
I am in The United Kingdom, I have my CAA Pilots/Flyer ID and Operators Licence, I have £12,000,000 Public Liability Insurance, sounds excessive I know but the cost is £36 per annum, will certainly cover me for most mishaps on my part.

I purposely went out a found a small lake to try out flying over water and was amazed at the little Mini 2. The lake is a fly fishing lake and has a movable fountain on it to help keep the surface clear of debris.
I flew five feet over the top of the fountain, bearing in mind that the fountain is only 3 feet high, so I was about 8 feet off the surface water.
I hoovered over the fountain for about 3 minutes just 5 foot above the spray, the Mini2 held station vertically and deviated about 12 to 18 inches horizontally, at no point did it try to land, Maybe it would have done if I had brought it down another couple of feet.
This exercise has given me more confidence in the capabilities of this little beastie.
I did video the flight but not sure how to post it on here, (I will give it a go).
Nope just a comes up with a http://, not going down that route.
My video makes it look closer to the fountain than I actually was as I zoomed in. I was 8 - 9 feet max above the lake surface.

Manual/Pro, Cine Mode 1080p, 25 FPS & 50 Shutter Speed,16 ND filter.
If you put it in Google Drive and make it accessible to anyone with the link that tends to work.
 
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