Labroides Posted at 4-9 20:48
Yes, seriously.

Im not feeling well - covid - so hope this doesnt come across too harshly, but it seems to me all you want to do is argue for the sake of arguing. You cant even be bothered to read posts you are responding to.

I'm way to tired, and way too old, to play this game any more. Plus I promised myself long ago not to get sucked into any more internet forum arguments. No one ever wins  - especially when arguing with people who just want to argue.

So... I give up. You win. Have a nice day. Im going back to bed.

Larry3215 Posted at 4-10 14:48
Im not feeling well - covid - so hope this doesnt come across too harshly, but it seems to me all you want to do is argue for the sake of arguing. You cant even be bothered to read posts you are responding to.

I'm way to tired, and way too old, to play this game any more. Plus I promised myself long ago not to get sucked into any more internet forum arguments. No one ever wins  - especially when arguing with people who just want to argue.

Thanks for the advice Larry ...

You asked (seriously) and I answered to explain for you.
But you didn't believe when I gave you facts, and I explained again in more detail.
Now you come back telling me I just want to fight and I didn't even read your questions !!!
You don't know what you are talking about.
Come back some day when you have a drone problem and need help.

Mine does it as well, I guess it gets confused on elevation when over water. Doesn’t pick up on it.

mikereynolds55@hotmail.com Posted at 4-19 17:45
Mine does it as well, I guess it gets confused on elevation when over water. Doesn’t pick up on it.

Your drone probably doesn't.
Your drone has good height sensors that don't "get confused over water".

It's drone flyers that get confused over water.
To get to the bottom of what your drone is really doing, you could do what the OP didn't and post flight data for analysis.
See the first reply in this thread for details of how to do that.

mikereynolds55@hotmail.com Posted at 4-19 17:45
Mine does it as well, I guess it gets confused on elevation when over water. Doesn’t pick up on it.

Hi,

It all depends how low your were flying over water.
If the InfraRed height sensor does not measure a steady height each time, than height droppings can occur.

It is 'normal' **  for a DJI drone to get confused flying low over, mainly streaming,  water.
** Normal as not normal in the sense that remote pilots does not want this to happen....but it will happen sometimes !

I fly a lot low over water and this, uncontrolled lowering height, happens to me few times in many flights.

I will add a video to my text later, example of an unexpected lowering of height flying low over water.

About the video ; Low flight over water, as always i look only and only at my drone, not at the screen!.
I saw it lowering a little, so direct UP on the controls.
After analyzing the logs, InfraRed height sensor shows a drop of 40 cm (so Eyeball mark1 can see a 40 cm drop from fly height of 160 cm).Ofcourse the valid question : does this height value in the flightlog represent the actual height drone>water surface?
But i noticed the height drop, so i pulled UP.


I was not confused (were you ? ofcourse not) flying low over water, just watching carefully how my drone (this time my MavicAir2) was flying.
But does the log shows always the correct data in such droppings?  No (seeing many logs), baro height shows more or less the same value and the vertical speed does not show the height drop motion.  



Cheers
JJB  [ Chart by FRAP ; the 'best' software for flightlog analysis ]

LV_Forestry Posted at 4-6 10:02
It's normal with these drones

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.

Sir, I bow down to you, because you must have balls of steel!

2 metres over water.....screw that..... Just to be safe I'd maybe go as low as 50ft....but oh my god it must take nerves of steel to do a 1-2 metre flight over water with any drone.

Matt

Staffydog33 Posted at 5-5 06:46
Sir, I bow down to you, because you must have balls of steel!

2 metres over water.....screw that..... Just to be safe I'd maybe go as low as 50ft....but oh my god it must take nerves of steel to do a 1-2 metre flight over water with any drone.

It's no drama at all, as long as there are no waves and you can see the drone.
It's just like flying over dry land at 2 metres.

I've been flying over the sea as of late in sport mode and very low and it looks awesome ! Not had any issues with it trying to descend, I think the problem is when you hoover over the sea or water then it gets confused and descends!  Stick it in sport mode over the sea and water and fly it looks very cool .

DroneWithJase Posted at 6-17 14:45
I've been flying over the sea as of late in sport mode and very low and it looks awesome ! Not had any issues with it trying to descend, I think the problem is when you hoover over the sea or water then it gets confused and descends!  Stick it in sport mode over the sea and water and fly it looks very cool .

Do you realise that you have just doomed you drone and that it will take a dive on its next over water flight?

Seriously though don't let past behaviour lull you into a false sense of security, watch it closely when low over water. The low height alone means you won't have much time to realise what is happening and react.

DroneWithJase Posted at 6-17 14:45
I've been flying over the sea as of late in sport mode and very low and it looks awesome ! Not had any issues with it trying to descend, I think the problem is when you hoover over the sea or water then it gets confused and descends!  Stick it in sport mode over the sea and water and fly it looks very cool .

Did you take any videos? How low were you flying?

DroneWithJase Posted at 6-17 14:45
I've been flying over the sea as of late in sport mode and very low and it looks awesome ! Not had any issues with it trying to descend, I think the problem is when you hoover over the sea or water then it gets confused and descends!  Stick it in sport mode over the sea and water and fly it looks very cool .

All 3 of mine, (previous Mini 2), P4P and now the Mini 3 Pro all descend to some degree when using sports mode, couple that with water and i would say that you were nowhere near low enough for it to have an effect or show noticeable descent.

If you was under 3m, i wouldn't love to see some of the videos and flight logs

Labroides Posted at 4-9 20:48
Seriously? More than one post - including one from me that you replied to - mentioned that its in the Owners Manual.

Yes, seriously.

Well my recent experience rather confirms this.

I wanted to shoot with my hand-held camera and MP3 a castle ruin on a small Island, which was just over 1km away over the sea with occasional sand flats. Access is only by boat although due to the tides when I got there, no boats.

This is where the drone saved the day and not for the first time.

There were some gulls about which I didn't want to antagonise so I flew out at 70m, over the sea and once on the Island I then came down to between 15-30m when at the ruin. I then went back out over sea next to it and back on land several times up to 1.5 km away by this point.

I had no problems whatsoever and it performed superbly, except I got the the occasional high wind warning with a gust.

I can confirm over streaming water the DJI 3 mini does some weird drifting in all directions. Raising altitude helps. If the shot calls for flying close to the water just be extra reactive and keep an eye on the drone.

The guy saying it’s nonsense is completely wrong. These issues are very real.

Dennis Bosher Posted at 6-30 07:01
I can confirm over streaming water the DJI 3 mini does some weird drifting in all directions. Raising altitude helps. If the shot calls for flying close to the water just be extra reactive and keep an eye on the drone.

The guy saying it’s nonsense is completely wrong. These issues are very real.

The guy saying it’s nonsense is completely wrong. These issues are very real.
The guy who said that drones don't descend over water knows what he's talking about.
The people who claim it happens never supplied recorded flight data to show what actually happened in their incidents or why.

Labroides Posted at 6-30 14:46
The guy saying it’s nonsense is completely wrong. These issues are very real.
The guy who said that drones don't descend over water knows what he's talking about.
The people who claim it happens never supplied recorded flight data to show what actually happened in their incidents or why.

He clearly doesn't in this case. Absence of Evidence is not Evidence of Absence. The fact of the matter is... Multiple people have experienced this. To form a reasonable conclusion one would focus on all available evidence, not just the one piece that is missing.

But just to put this issue to rest and acknowledge that it at least exist... this is a link to my flight data over the weekend where I again experienced this issue over water. Normally it only happens over moving water for me, this water was still. If you scrub to 1:22 in you will see I am in a hovering state. Suddenly without input the drone starts steadily descending. Shortly before that around 1:20 I did descend some, and the sticks return to center just before it descended on its own.

Since you know so much about these drones... what do you think happened? I have a link but apparently no permission to post it. :/

Labroides Posted at 6-30 14:46
The guy saying it’s nonsense is completely wrong. These issues are very real.
The guy who said that drones don't descend over water knows what he's talking about.
The people who claim it happens never supplied recorded flight data to show what actually happened in their incidents or why.

phantomhelpDOTcom/LogViewer/4D4GC9LWBR70BY6MWOUE/

Dennis Bosher Posted at 7-18 09:05
phantomhelpDOTcom/LogViewer/4D4GC9LWBR70BY6MWOUE/

Hi,

Had a look at your flightlog, your uncontrolled descent   and climb after wards....
See m chart of  your data.

At 1m21.5 your RC down input to zero, see the vertical speed goes from approx 7 feet/sec to zero after this.Initially your drone stabilized in height, see the blue baro height line.
Shortly after the IR height sensor is measuring height, befor that is wasn`t. See where the white line (not measuring) turns into green (measuring)
At the same time your done descended slowly....but no vertical speed down values!  this is incorrect ofcourse.
(both baro height and IR height values are showing descend move, so it did actually descended)

After your RC stick UP command (4x shortly), your drone started to climb on its own (yellow line) and down again (red line), finally steady at height.
in FRAP > Baro height line is automatically coloured yellow or red if height changes without RC UP/DOWN input!

I have seen few logs with uncontrolled descending the moment the IR cannot measure height, this is the other way around.

Height is controlled by the baro sensor and assisted al low height with the height info from the IR sensor.
Going down without vertical speed going down will not stop the descent...

What can you do ?  hope DJI will answer this.For me (flying often low over water) ; always keep good eye on the drone and always be ready to pull UP !

PS see last part of this vid > https://forum.dji.com/forum.php?mod=viewthread&tid=294010  and see my post in this thread. In both videos my drone lost height.

Cheers
JJB    [ Charts by FRAP ; the 'best' software for flightlog analysis ]

JJB* Posted at 7-18 10:51
Hi,

Had a look at your flightlog, your uncontrolled descent   and climb after wards....

Thank you for your reply JJB.

As soon as i noticed it was descending (visually), I tapped up on the left stick, I didn't recall it continuing to ascend until you mentioned it. I also recall tapping up and down on the left stick thinking maybe it was not returning to zero and was sticking. Ultimately as I gained altitude it returned to normal flight.

I also noticed from the data that just before the descent it was not utilizing the height sensor. What bothers me is while this seems to happen to some it also seems that it does not happen to most, therefore it could be a problem with the hardware/firmware. Should I contact support?

Thanks again for taking a look.

Dennis Bosher Posted at 7-18 13:54
Thank you for your reply JJB.

As soon as i noticed it was descending (visually), I tapped up on the left stick, I didn't recall it continuing to ascend until you mentioned it. I also recall tapping up and down on the left stick thinking maybe it was not returning to zero and was sticking. Ultimately as I gained altitude it returned to normal flight.

Hi,

Pleasure to help.

If the IR height sensor gets out of range or cannot measure height, this is seen in the PhantomHelp csv.
The last height measured is copy paste into the next records until sensor is measuring height again.
Normal behaviour that is.

Test yourself, take off and slowly raise height to 150 feet, down stick and land.
Check the values in the log, see how baro and iR height both shows a climb, IR height stops out of reach. Often going down the value at wich measurement starts is often lower than the way up.

Range for the IT height sensor depends on type of drone (see manual), only in 'good' conditions this max range value is seen in the log.

When flying low and slow over water, IR sensor measures height (most if the times), increasing speed > IR sensor 'stops' measuring. (just give it a try yourself)

cheers
JJB    [ Charts by FRAP ; the 'best' software for data and visual flightlog analysis ]

Labroides Posted at 6-30 14:46
The guy saying it’s nonsense is completely wrong. These issues are very real.
The guy who said that drones don't descend over water knows what he's talking about.
The people who claim it happens never supplied recorded flight data to show what actually happened in their incidents or why.

Really curious what your thoughts are now that someone has posted flight data confirming uncontrolled decent over water.

BRAP Posted at 7-20 09:13
Really curious what your thoughts are now that someone has posted flight data confirming uncontrolled decent over water.

I looked at his data after JJB posted.
I didn't see anything that showed that being over water caused a problem.
His drone was sloppy at holding altitude one time and it happened to be well above water at the time.
But it had no problem holding altitude when over water for the rest of a long flight.

I've flown 85 kilometres over water this week and thousands of kilometres over water in the last few years without seeing this alleged issue.
I've analysed the data from people who claim it's a thing and usually found another explanation in the data.
Do you have any data from an incident where you believe your drone was unable to maintain altitude over water?

Still waiting to see any flight data from

Labroides Posted at 7-20 14:51
I looked at his data after JJB posted.
I didn't see anything that showed that being over water caused a problem.
His drone was sloppy at holding altitude one time and it happened to be well above water at the time.

You just saw clear data of altitude hold problems over water at a specific altitude when vps sensors were activated. VPS sensors were not activated again until over land. These situations DO NOT HAPPEN OVER LAND WHATSOEVER.  The ONLY time it happens, and it's been multiple. is OVER WATER. And it doesn't happen all the time. But WATER is the common denominator here. Just because you do not have problems with this, does not mean they do not exist for others. You claim you can look at the data and it will determine the problem... So what was my problem? Is my VPS bad?

Dennis Bosher Posted at 7-20 17:41
You just saw clear data of altitude hold problems over water at a specific altitude when vps sensors were activated. VPS sensors were not activated again until over land. These situations DO NOT HAPPEN OVER LAND WHATSOEVER.  The ONLY time it happens, and it's been multiple. is OVER WATER. And it doesn't happen all the time. But WATER is the common denominator here. Just because you do not have problems with this, does not mean they do not exist for others. You claim you can look at the data and it will determine the problem... So what was my problem? Is my VPS bad?

No ... your VPS was just fine and recording the height whenever it was in range.That your incident commenced with the drone beyond VPS range, (so there was no data from the water's surface), and continue when VPS was accurately recording the descent makes it look like the water had nothing to do with it.
Having a brief fail to hold altitude incident once when you happened to  be over water doesn't show that there is a problem with drones wanting  to descend when over water.
If there really was such a problem, the forum would be awash with evidence of it.

Dennis Bosher Posted at 7-20 17:41
You just saw clear data of altitude hold problems over water at a specific altitude when vps sensors were activated. VPS sensors were not activated again until over land. These situations DO NOT HAPPEN OVER LAND WHATSOEVER.  The ONLY time it happens, and it's been multiple. is OVER WATER. And it doesn't happen all the time. But WATER is the common denominator here. Just because you do not have problems with this, does not mean they do not exist for others. You claim you can look at the data and it will determine the problem... So what was my problem? Is my VPS bad?

I've had a Mavic Mini descend when low over fairly shallow water, this was at the end of a 'speed run' and it was visible with my eyes on the drone.
Rather than get into a debate with anyone I'd suggest that you just 'accept' that it can happen, which you seem to have done, and watch the drone like a hawk when low over water. Preferably with eyes on the drone rather than the screen, and be ready to counter any uncommanded descent if you even think it is happening, better safe than sorry.
If I am low over water my thumb is ready to give the drone throttle if I even think I detect a descent, better to lose the view than the drone.
Generally, for me, low over water will either be
a) at the end of a commanded vertical descent, to get the view/shot, followed by a climb back to a 'safe' height or
b) at very slow horizontal speeds, the above "speed run" was, for me, a one of and has not been repeated.

Sean-bumble-bee Posted at 7-20 22:07
I've had a Mavic Mini descend when low over fairly shallow water, this was at the end of a 'speed run' and it was visible with my eyes on the drone.
Rather than get into a debate with anyone I'd suggest that you just 'accept' that it can happen, which you seem to have done, and watch the drone like a hawk when low over water. Preferably with eyes on the drone rather than the screen, and be ready to counter any uncommanded descent if you even think it is happening, better safe than sorry.
If I am low over water my thumb is ready to give the drone throttle if I even think I detect a descent, better to lose the view than the drone.

I have accepted.. this guy just gets under my skin with his know-it-all attitude, claiming he can do this and he can do that and everyone that has a different experience is talking nonsense. Even denying it with the evidence he asked for right in front of him.

I love the drone and this has been the only quirk that worries me from time to time. But if it's some kind of defect and it truly should not do that, then I want to know. But if it is in fact a common thing that comes from sensor confusion then I guess it is what it is.

Thanks bud.

Labroides Posted at 7-20 19:48
No ... your VPS was just fine and recording the height whenever it was in range.That your incident commenced with the drone beyond VPS range, (so there was no data from the water's surface), and continue when VPS was accurately recording the descent makes it look like the water had nothing to do with it.
Having a brief fail to hold altitude incident once when you happened to  be over water doesn't show that there is a problem with drones wanting  to descend when over water.
If there really was such a problem, the forum would be awash with evidence of it.

It's multiple accounts of brief fails.. Always when over water. Never when over land. It doesn't take a rocket scientist to see the correlation.

You still didn't explain what went wrong regardless. Despite claiming you would be able to know from the flight data.

It is in the manual!!! RTFM!! Especially the Using the Vision System section.

Dennis Bosher Posted at 7-21 09:49
It's multiple accounts of brief fails.. Always when over water. Never when over land. It doesn't take a rocket scientist to see the correlation.

You still didn't explain what went wrong regardless. Despite claiming you would be able to know from the flight data.

this guy just gets under my skin with his know-it-all attitude
And how about your know-it-all attitude, aggressively asserting that it's a real problem without having seen actual evidence to proves it?

But if it's some kind of defect and it truly should not do that, then I want to know.
So would I and that's why I want to see the evidence, rather than accept anectotal accounts that don't have evidence to support them.

It's multiple accounts of brief fails.. Always when over water. Never when over land. It doesn't take a rocket scientist to see the correlation.
Any kind of scientist knows very well that correlation is not causation.
Scientists look for evidence to support a hypothesis, before declaring the mystery solved.
And it doesn't take a genius to observe that until you came along, none of the claimants in this thread bothered to provide any flight data to back up their belief.

You still didn't explain what went wrong regardless. Despite claiming you would be able to know from the flight data.
I explained as much as the data showed .. that the drone was sloppy with it's altitude holding, just once.
I can only say what the data actually shows and it didn't show what caused the brief incident.

Labroides Posted at 7-21 15:35
this guy just gets under my skin with his know-it-all attitude
And how about your know-it-all attitude, aggressively asserting that it's a real problem without having seen actual evidence to proves it?

And how about your know-it-all attitude, aggressively asserting that it's a real problem without having seen actual evidence to proves it?

Do you understand what evidence is? I have observed it happening multiple times. So have others. That is evidence. Even if it is an expected issue that has to be accepted, and not an actual defect, the problem exists


So would I and that's why I want to see the evidence, rather than accept anectotal accounts that don't have evidence to support them.
anecdotal*



Any kind of scientist knows very well that correlation is not causation.
Scientists look for evidence to support a hypothesis, before declaring the mystery solved.

Yes and part of that evidential  process is be able to predict and reproduce an outcome. Done and done.


And it doesn't take a genius to observe that until you came along, none of the claimants in this thread bothered to provide any flight data to back up their belief.

The fact that several people are experiencing similar behavior's.. IS evidence. It may not be enough to determine the cause, but it is enough to warrant looking into it and to suggest some type of issue.


I explained as much as the data showed .. that the drone was sloppy with it's altitude holding, just once.

Yeah.. Once when it was over water, after it happened i stayed over land.


I can only say what the data actually shows and it didn't show what caused the brief incident.

I'm not trying to be a jerk to you. Just your refusal to acknowledge that there may be an issue, when several people have experienced the issue, simply because you could not see the data really triggered me I guess. I do hope you will consider those that experience things first hand as reasonable evidence but I'll leave it here and wish you well.

Dennis Bosher Posted at 8-13 10:23
And how about your know-it-all attitude, aggressively asserting that it's a real problem without having seen actual evidence to proves it?

Do you understand what evidence is? I have observed it happening multiple times. So have others. That is evidence. Even if it is an expected issue that has to be accepted, and not an actual defect, the problem exists

Hi Dennis,

Evidence found enough in many logs.
Flying low over water, streaming water is worse, VPS looses height measurement. (well withing IR range)
When this happens height performance got worse, and sometimes drone will descent!.

I fly a lot low over water, and have seen this many times happening on my drones. So if others claim that this is not a problem, take my advice;  stop discussing and don`t get all the non relevant discussions replys

cheers
JJB    [ Charts by FRAP ; the 'best' software for data and visual flightlog analysis (JJBFRAP@GMAIL.COM) ]

Use floatation device on it in case it wants to land in water. Away from the sensors on bottom