Do I need to turn off downward VPS flying over water?

[mlaczek]

Honestly there is not enough data to make that call.

Rob

thank you Rob!

 

[RAMJET-1]

Turn off VPS when flying over large bodies of water. And then turn it back on when your getting ready to land.

There seems to be enough evidence to suggest that the Mavic during hovering over water will often be fooled and start to depend on false info from the VPS. The craft will think it is at a level height when in fact it is descending lower and lower towards the water. Not enough is known on why this happens, but enough cases have happened to make it prudent for people to turn off the VPS.
This does not apply if your flying 60ft above the water and out of the VPS range.

Rob

Thanks for this Rob. Explained very well and to the point!

 

[frankiez]

After reading what others have experienced, I didn't want to take the chance since I was 40 miles out into the Gulf of Mexico. I didn't feel inconvenienced to just go into the settings and turn it on/off. It gave me some peace of mind.

 

[nesstimo]

I realize this is an older thread but came across it as I was researching the issues I had with my Mavic flying over a river yesterday. I intend to do a lot of flying over the water this summer across the Great Lakes of Michigan and therefore, testing and researching any potential issues that may arise. I did not turn off my VPS sensor while flying over the slow moving river and immediately found that I was drifting horizontally some but most definitely loosing elevation at a slow rate. I was initially only flying at about 4-5 feet off the water but due to the amount of low hanging trees and winding river banks, I decided it best to stay above. Therefore, it is my conclusion there is horizontal and vertical drift associated with the movement of water and could quickly get you into trouble if you were looking at settings etc. on the controller/phone. I will certainly be turning off my VPS if flying over water in the future.

 

[Strafe1]

This provides a compromised solution, but better than leaving VPS on. If you are flying in VPS detection range (below 10m) over water, it has been shown that the sensors may get confused and the Mavic may descend. With VPS off, you have only GPS holding position so there will likely be some slight drift to contend with. This is good to know when flying in a tight corridor.

 

[Glasswalker]

There are documented crashes (mavics landing in water) as a result of VPS being confused. Where flight logs were uploaded and shared, showing that the altitude suddenly was detected as a negative number. Under this circumstance the right stick movements immediately trigger an auto-landing (which depending on timing could go very badly). (getting late, don't have energy to go dig up the threads, but they are here on this site)

In addition there are cases where as mentioned altitude "drifts" causing the drone to slowly "correct itself into a watery grave". Usually the pilot can overcome this, but it's still dangerous.

Ideally, downward VPS off over water for safety.

Note: downward VPS is technically a sensor cluster which cosists of stereo machine vision cameras, AND an ultrasonic (sonar) ranger. Which are used in concert. Both of these systems can be confused by moving/choppy water. (visual system sees constantly changing patterns, can't lock onto the topology of the ground below, or accurately read distance, and the sonar gets reflected all over the place by the surface, and can't get a clean read). And the flight controller on the Mavic uses some kind of sensor fusion to do checks between available sensors to determine if something is out of whack... As a result, both the vision and ultrasonic being confused might cause chaos it can't handle...

 

[kave]

I tried flying two meters above a river with vps on, Mavic drifted and followed the rivers surface. Next time I will turn off vps and see if it will be better.

 

[taryn]

There are documented crashes (mavics landing in water) as a result of VPS being confused. Where flight logs were uploaded and shared, showing that the altitude suddenly was detected as a negative number. Under this circumstance the right stick movements immediately trigger an auto-landing (which depending on timing could go very badly). (getting late, don't have energy to go dig up the threads, but they are here on this site)

In addition there are cases where as mentioned altitude "drifts" causing the drone to slowly "correct itself into a watery grave". Usually the pilot can overcome this, but it's still dangerous.

Ideally, downward VPS off over water for safety.

Note: downward VPS is technically a sensor cluster which cosists of stereo machine vision cameras, AND an ultrasonic (sonar) ranger. Which are used in concert. Both of these systems can be confused by moving/choppy water. (visual system sees constantly changing patterns, can't lock onto the topology of the ground below, or accurately read distance, and the sonar gets reflected all over the place by the surface, and can't get a clean read). And the flight controller on the Mavic uses some kind of sensor fusion to do checks between available sensors to determine if something is out of whack... As a result, both the vision and ultrasonic being confused might cause chaos it can't handle...

This.

 

[Johnny]

That's what I figured but I thought I'd ask if anyone has had any bad experiences leaving it on while flying low over water


iPhone 6S

I see in some old (pre-Mavic) posts online that you should turn off downward VPS when flying over water, but the Mavic manual doesn't mention it. I've seen a couple of videos now where people had their Mavic quite low over water - even in the ad video DJI made for Mavic it ends with it hovering quite low over water.

Those people who flew low over water, did you disable VPS?


iPhone 6S

I flew over water at like 1 m above and i had it on, nothing happened i think it was fine left it hovering there flew a bit all normal

 

[jerryherb]

flew the mavic over almost still murky brown river last weekend with VPS on just for SnGs. started about 6 feet off the surface. though it was not drifting sideways much, it sure went up and down steady as high as 30 feet and as low as landing height on its own. would definitely recommend turning downward VPS OFF over water

 

[joshnl]

In my experience, leaving VPS on is really only a problem when you're over fast-moving water, such as a rapidly moving stream / river, with lots of white water for the VPS to pick up on (the VPS then tries to keep aligned with the white water, which causes it to move with white water, and it doesn't stay put). It can also be an issue when flying over rough ocean, with lots of waves. In any of these situations, it's only an issue if you're flying within about 10 meters of the water.

 

[snipe]

In my experience, leaving VPS on is really only a problem when you're over fast-moving water, such as a rapidly moving stream / river, with lots of white water for the VPS to pick up on (the VPS then tries to keep aligned with the white water, which causes it to move with white water, and it doesn't stay put). It can also be an issue when flying over rough ocean, with lots of waves. In any of these situations, it's only an issue if you're flying within about 10 meters of the water.