Flying Over Water - Downward Positioning Sensors On or Off?
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- เผยแพร่เมื่อ 5 ต.ค. 2024
- Exploring the topic of Downward Vision Positioning Sensors with the Mavic Pro and Phantom 4 Pro over water. Should they be turned on or off for the best and safest experience flying over water?
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What are your experiences with flying over water? Have you noticed better flight/hover performance with the downward vision positioning turned on or off?
Hi Ed! I always leave it on, and works ok for me! Thanks for the risky video! Cheers from Argentina!
I flew my Mavic over a lake in Southern Illinois quite a bit over the summer with no problems. But, I didn't really get any lower than 15 feet or so, I kept it moving, and I did turn off the downward sensors because I was going to have to hand catch it from a boat.
Hey Ed! First things first thank you so much for the videos!
I've done many many flights over water, under tight bridges, waterfalls and other similar scenarios... from my experience it goes like this:
Sensor off for sure! Once I had the drone raising under the bridge and I had to put it down almost diving with it into the water...
At 1:19 you pointed out you'r looking at the "H" value which is based on the take off position. What I do Instead is to look at the VPS value which will give you a more accurate distance from the water. I always trust the 1 meter (3ft) VPS reading and haven't had issues so far... Just make sure you keep an eye on the value as you fly and make adjustments so it doesn't go lower than that...
Happy flying!
Honestly I think you should try the same with the mavic but when actually flying, not hovering. I dont think you often hover low over water when filming, you actually fly? The rippeling of the water would be different and maybe even completely gone underneath the drone when flying.
Mine hovers nice and close to water without issue.
I think its better to leave it on,i would rather it climbs than fall :)
I wouldn't DARE do that experiment.. thanks for the info.
BEST video I've seen yet in regards to flying over water. I've wanted some low flying water footage and this was by far the best information I've seen about it. GLAD you risked your drone over water before I risked MINE! Thanks for the video!
Glad you didn't lose any drones in your test. Thanks for sharing, Ed!
I tried a low fly over a beautiful smoky mountain rapid stream with sensors on , not good, took everything not to loose it in the water. Drifted left , right, forward, back, up, and down, all at the same time! lol. I did get some great slow mo water footage.
Rapid mountain stream with constantly chaotic visuals? No wonder the downward VPS was confused.
This was an excellent demonstration. I'm always nervous over water so I keep altitude but I have seen this phenomenon and didn't know the reason. While I will keep cautious, I can now properly react to such movements.
Dude you are a brave man. That was making me nervous, all my nails have been bitten off watching this video.
Great video, thanks for sharing.
As my main hobby is angling this has been a very useful video, as yet I've not had the courage to fly over still water or a river, however, I have floats as a just in case it does crash land and is recoverable, the river is a different proposition, so looks like leaving sensor on is a better option, cheers Ed
What a great test, I would have thought it was a forgone conclusion but that is "why we play the game" as they say. Good info, I'm going to be leaving mine on for sure.
You are the ultimate teacher. Keep it up. don't quit making tutorials.
Great test Ed, would have been curious to see how it reacts while flying horizontally across the water.
I've had similar experiences while flying above water - both the lowering and raising (w/ sensors on). Regardless, one has to pay close attention when flying like that.
Gutz Man! that's what we call a brave guy down here. Thanks for risking you're birds to show us exactly what happens. The debate is over, fly low over water at you're own risk.
So I recently tested this myself on a very clear mountain stream and I got so low that it went into landing mode, luckily shoving the sticks up sent it back into the air. But talk about heart stopper.
Sometimes my hand shakes from the early stages of Parkinsons Disease, but when I nearly flew 4,500 Feet in distance this morning, I was shaking really bad from the excitement and adrenaline. I'll fly over water with my Phantom 3 Standard, but not my Mavic Pro.
I caught a close splash down in this video. It’ll make you sick to your stomach. th-cam.com/video/17IRxYFD7so/w-d-xo.html
Thanks for the test!!
Thanks Ed. On my DJI Phantom 3 has the exact same result. It was safer with the sensors "on" and flying above 20 feet when over water. Thanks!
This was very enlightening for me. I can’t tell you how frustrating this is when I’m shooting real estate and I want to fly low over pools. Hard to make cinematic footage when it’s going up and down.
Thanks for risking taking one for the team, really good to know
Thanks for testing it out. It would have been interesting not only hovering but moving forward / backward as well.
GPS signal altitude error is always considerably worse than the horizontal (position error). Much of this is a matter of geometry. So it's natural to experience the quadcopter to hover quite stable over a certain spot over ground, but to wobble significantly in height. That was exactly what was observed in your test, only that the downward sensors over past 2 years became just robust enough to get you covered over open water. Things should become better with the GLONASS incorporated into the sensors.
I've had the drone report it had reached maximum altitude when it was only 10' in the air, over moving water. I have also seen the drift issues you experienced caused by firmware/ device software mismatches over land.
I lost my first Mavic flying over Water under a bridge. It acted as if the compass or GPS was off. Lost altitude, then gained altitude and hit up under the bridge and crashed. The water wasn’t my main issue, but all the concrete and steel really confused it. It would be great to see a low lying bridge test that you can walk under and safely do a test. I lost pretty much all control flying under a solid bridge. Lesson learned.
Were you going slow so that it spent a long time under there?
Mitchell Hubbard Yes. I actually made it under and through the bridge once before, but the drone lost altitude closer to the water so I went forward faster. The second time was slower and that’s when I couldn’t accelerate. It had a mind of it’s own. All avoidance sensors were on, so I believe it would allow me to lower the drone closer to the water to get it out from under the bridge. It hit up under the bridge and crashed into the water.
O shit. . And I which was planning to fly under a big bridge and then up and over it .. Don't think I dare that now with my P4 !!!
Matthew Trudeau I did the same thing but luckily I didn’t lose it, but it does effect the gps and compass probably cause of the magnetic field coming from the bridge.
Going under bridges and obstacles is a huge no-no. The drone can quickly enter ATTI mode and fast start drifting because the lack of GPS signal or compass disturbance.
Hi! thanks for the great video! awesome work!
I have tried flying over some bodies of water like ponds and seas and haven't experience (yet) any troubles with the sensors while it is 'on' but I don't rely (and trust) on the downward sensors of my drones when flying close over the surface (water), and I am very attentive when flying on such. It's like I am flying on manual mode, so better if it's switch it off.
My opinion on why DJI suggests it has to be turned off: On solid ground, the sound (sonar) is effectively bounced and detected back by the drone, so it knows how high it is from the ground. But when it is over water surfaces, maybe the sound doesn't bounce back as effectively...
For the DJI spark, it uses infrared, but I think, same idea.
I'd rather control it manually when flying over water than it (the drone) miscalculating and crash. ;)
Excellent video. Very relevant as most of my flying will be out over the ocean from a boat.
I think that what we are getting without the vision or Sonar positioning systems is an altitude measurement purely and simply off the barometric sensors.
Close to the ground the prop wash is actually creating a low-pressure zone which the barometric sensor is interpreting as rising up.
I am thinking that the same behaviour might occur over solid ground when flying at a lower altitude without the vision and sauna downward sensors enabled.
I feel a science experiment coming on.
Good video Ed
This is the answer. It has not other reference to use except GPS which is greatly reduced accuracy due to the acute angle resolution being out to 6-8 decimal places or more.
What do think my problem was on my Mavic Air? Sensors and APAS was on. th-cam.com/video/17IRxYFD7so/w-d-xo.html
Wow! Never gave it much thought about how the water would effect that. Nice job. I'm still flying the Mavic I bought from you last year. Got a Spark 3 months ago but haven't had time to mess around with it.
Great contribution to understanding self-generated hazards to the Mavic. I'd always rather watch somebody with better reactions fly their drone for these tests. Thanks.
Made me nervous as well. Good test!!!!!! Thanks for your expert insight:)
From my experience - keep the visual sensors on all the time. If you fly high enough it does not affect at all your positioning. If you fly around 2-3 metres over the water and in constant move all the time - it helps maintain the same height. Maybe the reason this test "failed" is because you were hovering over the water. When in move the drone "reads" the surface differently, not as a plain surface... That's my guess. Owner of a mavic pro
Hi Ed,
I have a Mavic and I test / experienced the same behavior than yours with the positioning sensors on; uncontrolled climbing and drifting. With the positioning sensors off it was stable. Well, as stable as a Phantom 3 Standard, as the height is now only measured trough barometric sensor and GPS, which is less precise also because the barometric sensor is affected by temperature changes.
Man, you have balls... I thought you were going to trigger auto landing by accident with the mavic at one point. Great video!
I just ran into an issue with my spark over water. My drone took off uncontrollable at about 5 feet, I was able to gain enough control to direct it into some soft brush. I am glad no one was in the path, as it was haulin ass. Needless to say I did not do that again lol
Hey, that's my stomping grounds! Just got my Mavic Air on Friday and that was the first place I went to shoot. Perhaps I'll see you out there sometime.
When you disable the vision sensor system I don't think you disable the downward ultrasonic sensors. They might be confused by the ripples on the water.
Interesting test. I wonder if it would yield the same results if moving across the water rather than hovering? Cool you took the time to test two different craft. Nicely done man.
In my opinion drone somehow stops trusting optical sensors and maintains barometric altitude. Which can be somewhat affected by wind gusts or orientation of drone relative to wind. I don't want to test it, I almost drowned my mavic mini flying approximately 4m above the pond.
I remember seeing something that flying over water with VPS on could trigger the drone to land.
Awesome video Ed I cant believe that I was nervous just watching you do this ? Thaks alot - I live by the coast and fly over water alot but steer clear of going this low - if you are ever in the UK feel free to visit we have some ace places to shoot footage !
My experience with still water is the same as yours. I hadn't though to try rough water, but I'll do that next.
Propwash may explain the drone's behavior when the sensor is off, but it doesn't explain why the sensors indicate the drone is maintaining its altitude when they're on. Essentially the water is affecting the sensor's ability to accurately judge altitude.
Thought it was worthy to note.. I own the Phantom 3 standard and the Mavic and I have found that the lack of sensors on the Phantom 3 allows it to hover over water nicely but I wouldn't go less than 5 feet high with anything.
I haven't had too much experience with flying my Mavic over water, but in my last video there's a bit where I fly it very low over a canal, and the controls did become very wonky... At times the drone even moved to the sides when the only input I gave it was to fly forward. Definitely need to do more research/experimenting on this in order to make it a safe thing to do.
First time out mith my Mavic Pro it did exactly this over a deep river and actually ended up in the water!!!!! thankfully the props still got it out of the water and after a few days of acting very strange, once dried out properly it did work ok again - phew!!!!!
Great video Ed. Hell. My rule of thumb. When over water fly high and fast. LOL.
This is a good analysis. My experience has been even with the sensor on, the drone started acting crazy and it took off like 100 ft up quickly. The other problem I had which I don't understand, If I land inside a building, for example, imagine an octagon building with a huge space in the middle, as soon as I start landing, I lose contact then Immediately I increase altitude to gain control. scary, but that's how I found out.
I lost my first Mavic Pro Platinum in the lake before I learned not to trust the altimeter in windy conditions. I was taking videos of windsurfers in winds of 20+ mph. Sport mode. Altimeter showed 30 feet but I clipped my friend's sail head (15') and Mavic tumbled into the water. Practicing over land in windy conditions I learned that it's the wind, not the water, that creates the error. In winds, altimeter shows 50' when I am below 30'. Air pressure from wind tends to create errors over the course of the flight. After landing and re-takeoff, readings were accurate until later in the flight. I recently read a forum post which pointed out that in windy conditions, the VPS number to the right of the altimeter is more accurate.
Interesting. My first flight last week on my mavic, I flew over a pond, probably 15 cms above the water without a problem. Watching this today makes me feel very nervous. I think I just got lucky. I've flown 15 - 20 cms over river waters several times with a bebop 2 and never had any issues. Thanks.
First, I always fly with Enable Vision Positioning OFF and Landing Protection OFF. At the beginning of last summer I would notice when transitioning from land to over water (4' high) the Mavic would take a dive for the water. Later in the summer after a few firmware upgrades and calibrations the Mavic no longer dove toward the water (calm or waves) at any height. This allowed for some great video of ducks taking off a few feet above a calm lake. Never flew into the water once all summer.
I lost my Mavic 2 Pro flying about 10 feet above the ocean which had four foot waves or so. I was flying down into the water and I didn't notice until it was too late. A wave came by and clipped the front props. It then shot skyward, flew back into the beach by about 50 feet horizontally, then dropped from 100 feet high or so into the wet sand. After doing my best to clean it, it would turn on, but had red exclamation "!" warnings ACROSS all the settings.
Today, I took my new Mavic 3 and flew 8-10 feet above the ocean with wavy conditions and it was all I could do to keep it from flying itself down into the water. FINALLY got it to climb, but then I had very little control over the horizontal flight. Did manage to fly it back to me (as I ran as close as I could to it) and land it in my hand. CLOSE CALL. I will never fly the drone that close to the water again. From now on, 25 feet or higher.
Nice test.Ed ! Very interesting
Video was quite informative on some doubts I've been having regarding this, I just started flying my Mavic not too long ago, and a friend told me about someone's Mavic that flew too close to water that it got sucked into it, and dragged by the current, that had me paranoid.-
I was told not to fly close to the water when I was training for drones. Due to the limitations of the sensors, there has been a lot of experience that drones go into the water without any control.
Cool video. The mavic 2 gave me a warning about the metal fence around my yard and then it just went full blast into a tree. I could've landed it manually perfectly fine. It had GPS. Sensors are great but good to know how to turn them off
Great video, and and looked better just being out for a bit. Ha. I was flying over the river yesterday and I wasn’t comfortable under 20 ft ... ha...
Good video, I flew over the water a lot. This really help me. Thanks
Excellent test. Thanks Ed!
The VPS camera sensors being able to visually see the bottom of the shallow lake probably keeps it from drifting laterally, but isn't altitude determined by the ultrasonic sensors? Those probably can't get a good reflected reading from the water (or maybe even fluffy snow).
Dude, you have me hear nervous and with anxiety. It’s not even my drone but just knowing something can go wrong and something happens to the drone has me screaming inside. LMAO. Thanks for sharing the video this way others can learn from this video. 👍🏼🙏🏼👏🏼👏🏼
depends on what kind of water we are facing. clear, unclear, moving, still, wave, waterfall, each has different affect on VPS.
Mavic Mini over the pond with moderate gust wind: flying above the pond at ~4m altitude above water and ~1.5m above starting point ... turned back ... drone dropped to ~1m above above the water in perhaps five seconds and i was informed by friend watching it (i watched phone screen) and I managed to pull up in time. Uploaded log file showed that drone went up by few meters according to barometer (which was not true), so drone likely tried to compensate it.
Scary, heart pumping
Very useful test. Thanks
Geez Ed. You had me nervous. I expected at any moment to hear your controller say “Landing“. How did the drones do while actually flying forward over the water? I have flown over water about 8 feet in the air in the past and had no problem with the sensors turned on using my Mavic. Hope you feel better.
Thanks Mike! Flying forward shouldn't be as much of an issue since GPS may start taking over at that point, but that was also more difficult to show on camera. It was easier to show the deviations from a hover than from a traveling drone...especially since the altitude readings couldn't be trusted.
Thanks for watching though, I was nervous too!
Great video as always, Ed! I'm always afraid my Mavic will go into auto-land and try and land on the water!
I thought the same, but I don't believe it will auto-land because it thinks that it is still 3 feet up. Of course, that could change quickly under these control-fooling conditions.
Mee to am so scared
Your ultrasound sensor comment might just be the case. Sound actually does travel in water much faster compared to air. And ultrasonic pulses does penetrate water quite well. not sure if they would hit bottom of the lake and reflect back, but the drone might just receive double or inaccurate readings.
As I'm wanting to buy soon this was great information.
What if you forget about the downward sensors and just put it in sport mode that turns off all position sensors or collision avoidance and I think that takes care of the problem
Found this in reccomended, Am gonna fly over water today tho, so thanks for the video
Better just to be safe and fly a little higher overwater why risk it remember DJI Care refresh does not cover your drone unless you can recover it so if you crash it in deep water hopefully you got some scuba diving gear too
Thank u for sharing this video very informative. 👍
Very nice. Definitely needed to see this. Happened to me b4 n i started panicking.
Fresh air does you good. Hope all is well.
This effect is certainly not caused by propwashed. The drone is not lowering fast enough to get that and it is too high to get caught in ground effect. It is much more likely that the Sonar is causing the issues, because even though the VPS is disabled, the Sonar is still active. It might be possible that it sometimes gets somewhat reflected by the water surface and sometimes the drone picks up reflections from the ground of the lake. This would cause it to conclude very different levels of altitude, which could cause the up and down movement (it could also be something that's not that, but similar in some way).
Additionally, turning off the VPS might not turn off the bottom cameras. You see, the vision positioning technically only means that the drone uses the bottom cameras to keep its position, and it is very well possible that the downward obstacle avoidance is still active after disabling the VPS. That would mean that, regardless of whether you turn it on or off, it will try to guess its altitude with the sensors and it will get it wrong. Either that or it is turned off, and it's only the Sonar that causes the issue when VPS is disabled (this would explain why it acts differently with VPS on and off).
It shoud be noted, though, that the drone will only ever drift with VPS on, since this is caused by the actualy positioning getting fucked up.
Wow....very gutsy....you got balls
There is no way that "the downdrafts" can "blow back up". I think that is people trying to make it look like they understand ground effect. But ground effect is only in play at very low altitudes, like under 1 foot or so, it could be the GPS inaccuracy. But good video, just wanted to make that correction.
Hello Ed 3 years ago I asked for a follow up with the mavic 2 pro over water test. Now I was wondering if you could do a follow up with the Mavic 3 drone over water test and lets post the results thanks for all the videos they have been informational
Great Vlog as always ED. I fly the Mavic(Personal) and the P4Pro(for work) every week and i always notice that the P4Pro is never as stable as the Mavic. Yes the Camera on the P4Pro is great but as an overall drone for stability, wind stability, etc, the Mavic is the better drone. I just turn off all the sensors these days, too many issues with sun and reflections for what i need to do
If it was prop wash causing confusion in the barometer readings then surely it’d happen over any flat surface in an open area, no? But this only seems to happen observably over reflective surfaces. I’ve no way to check this but it might be interesting to see if this happens over any highly reflective surface like a large mirror or space blanket? Those are made of aluminised Mylar, so no risk to the quad if experimenting.
Hi Ed, my mavic goes nuts over water too. Good to know that is "normal". With helicopters, within 1.5-2X the rotor diameter, it will bounce a bit on the rotor wash bubble similar to the ground effect in a fixed wing. Your mavic would have to reduce power to settle into that. My guess is that it was more the false altitude reading it is reacting to. I have always had inconsistent behavior close to the ground (
Hi Franny,
No, I haven't really had that issue on a still day with the Mavic over ground. On a windy day, you may lose a bit of altitude but not as much as the Phantom 4 Pro. With the Mavic, it's really only water that I see issues with, even with the downward sensors off. In that case, maybe it is the false altitude readings! Hard to say...
Thanks for dropping by!
@6:27 "However, if you're high enough that you're not causing prop-wash, then..." -You seem to change directions in this sentence and don't finish with any recommendation regarding sensors being on/off when drone is not prop-washing. I could be wrong, but for now I'm going to assume that 100' up the sensors are not in play and don't matter. It would be cool to see you test in that range between prop-wash and limit of sensors, say maybe 20'.
This was 4 years ago, this still the case, I’ve always kept them on but never flown that low.
Thanks for the video! I was wondering about this too!
Now I’m wondering what’s the safe altitude to fly over the water?
Thanks Ed! Great to know. Appreciate all your hard work. And the Spark? Any experiences to mention?
Drone altitude is determined by barometric pressure that is affected by temperature. Flying from land to water often results in lowering air temperatures, which makes the drone think it is higher than it really is, resulting in a descent. As the drone descends, the landing sensors kick in forcing the drone higher - hopefully. Once higher, the barometric pressure readings force my mavic 3 back down again - causing an inconsistent altitude effect when I fly near the water surface. I have found a 1 degree Fahrenheit change in temperature results in about a 1 foot altitude error. Since the landing protection is inconsistent over water, the chance of a drone going for a swim is fairly high if it flies into lower temperatures. I frequently fly over water, and I usually fly at least 10 feet above calm water, higher if waves are present to compensate for barometric changes due to temperature variations. So keep in mind that flying into lower temperatures, typically found when flying over water, will force the drone down.
I never understood why people said turn off your downward sensor off when flying over water!
Excellent video Ed !
my air 2 can fly about 3 feet above the water with no prob. Its scary when i stop and see the water when it tilts forward! I was low enough that I was 2/3 the height of one of the 5mph buoys
So, after watching the video and reading through the comments, I get the impression that, while it is relatively safe, the "safest bet" is to stay at a decent height while over water, correct?
GREAT info! i love watching ur experiments!!
Im thinking that the vision system doesnt see the water that good but does see it enough to keep it higher. Now Im not sure if the sonic sensors turn off with the vision or not but im thinking the sonic sensors dont read water very good and the closer you get and the bigger the wave produced makes the sonic sensor less sensitive. This is just my back seat observation.
2 things: (1) the term is 'rotorwash'. (2) rotorwash ground effect is zero when you're more than two rotor diameters above ground/water.
thanks
hello.
you cut off optical, but the infrared still on? may be that is the problem?
perhaps
Great video,thanks for showing this
Try this : switch OFF landing protection . I assure you this works . Test it first , over a kiddie pool or other "water hazard" . With this setting off , you can fly your Mavic an inch or less off the ground & it will not try to auto land. It works over water too 👍. I've flown mine merely inches over the surface of a lake many times like this. Like you, I can't afford to drown a $1000 + drone . Now pine trees , that's a different story :) BTW , I'm using app Verizon 4.0.3 on an iPad mini 4
That was crazy.. been flying over water a few times also close to the water.. never experienced that, mine was way more stabil, Maybe because you are close to shore it can sense the ground under the water an the water surface.
It cannot sense the ground )) It have pressure altimeter, sonic altimeter and the ir cameras.
Alex Morgun then how do You explain What it does in the video?? An why is mine not doing the same?
This was intresting! Isnt it just so that with the downward sensors turned OFF, the drone don´t act based on the altitude data it collects? And as you say, a sonic-signal on "moving" water...bounces it all over the place so the altitude data gets all wacky. I don´t believe for one second that these sensors are powerful enough to penetrate water and get the altitude from the seabed. I fly alot over water (always with downward sensors ON, turn it off if I have to handcatch) and noticed that when flying low, you have to keep the drone in motion or it will act really strange altitude-wize as your video shows. Really intresting video, makes you wonder what trigger that behaviour? Thumbs up from Sweden
Great test! Now i know why my mavic was not stabel last time i flu over water :D
It makes sense because when you are close it could see the ground beneath the water
When you're further out it can't see the ground under the water..
Question Rick. The water is shallow. Was it detecting the water or the lake bed? I have done this over the ocean in deep water with differing results.
Hey Phil, hard to say! I tried it further out and it wasn't such a dramatic change, but it was still bobbing around a bit. But i was apprehensive to try it too much since I wouldn't have been able to physically rescue it that far out!
I was thinking the same, seems like it was confused between the surface of the water and the bed of the lake. Either way better to be safe and not get that close
Nice video Ed, I wouldn't fly my Mavic over the water.Hovering is even more dangerous. I crashed my Mavic on ascending from a hovering point without any obstacle in the way.The Drone just flipped over and crashed on a neighbor's roof.DJI still investigate the failure but it looks like there are quite a few cases like that I found over the web
Were you descending fast? I have heard you can get caught in the downward prop wash and loose lift at the props. I think one of the newest firmware updates actually limits how fast you can descend. I also try to have a little forward movement on long descents and save the straight down for the last few feet.
One guy was hovering his Mavic about 10 feet and it flipped over crash found out one of the motors went bad maybe that could be it Dji fix it and send it back no cost good luck