I don't fly indoors. I have read that vps can cause some problems outdoors possibly. Should I leave it disabled like I now have it??
Disable vision positioning ?
- Thread starter Sig Man
- Start date
Leave it on for normal flights but if you are flying over water, especially if you plan to get within 10 to 20 feet of the surface you should turn the downward sensors off.
DJI says, on P23 of the manual, the VPS may not function correctly over water. That is borne out by users.
From experience I say turn it off when low over water. I fly often as low as a foot off the water often going under low hanging trees, etc and with vps on, it often does not see the water depending on surface condition, but as it goes along would suddenly detect the water surface and abruptly try to ascend, usually at the wrong time at the wrong place. Good example:
Leave it on, even over water. VPS does not affect the altitude of the P4, especially over water. Turning it off over water is a throw back to the P3 where it would change the altitude.
Absolutely not true, even DJI will tell you that flying over water under 10 meters the downward sensors will try to read the surface and not be reliable causing the AC to drop suddenly. I fly my P4P+ over moving water all the time and when I first started doing this when I got withing 10 feet of the surface the AC would act crazy, jumping up and down and moving side to side. Switching the downward sensors off eliminated the problem and I could hover over the water and get the videos and pictures we were looking for. Here is a quote direct from one of the DJI techs on their forum:
"I suppose "less reliable" would be a better term, as the VPS will try to read the water's surface when it's enabled with poor results. Disabling the VPS will alleviate the drops from happening, but flying under 10m will mean that every stick command would be paramount to its survival. You won't have a lot of room for error if you're not paying attention."
I agree 100%.... When I would fly over the ocean, It would drift sideways without stick commands. And always seemed to be drifting in the same direction as the current was going. Meaning it was sensing something and altering the movement of the drone without my direction.. Once turned off, I NEVER had the craft duplicate that type of reaction...
Just my personal experience, others may differ...
That thread is talking about using the downward camera for positioning. My response was to VPS changing the altitude of the Phantom. VPS does not change the altitude of the Phantom (unless it's at around 12" altitude, the ground is rising very slightly and the Phantom is moving at a very slow rate of speed... which does not happen over water).
The VPS downward sensors will cause the AC to climb/drop suddenly and drift side to side, and I know this from experience. The downward sensors (in the advanced section) will have a hard time allowing the ac to hover especially if the water is moving rapidly such as a river. I have photographed and video taped many waterfalls and the only way we can get the ac to stay reasonably still is to turn the downward sensors off if we are within 10 feet or less of the surface.
You are mentioning two different things, hovering and gaining altitude. They are two different things with separate controls. I'm not disputing that the downward facing camera might over-ride GPS (it did not on the P3) as I've not tested that on the P4. However, gaining altitude is not a function of the VPS at all (controlled by ultrasonics not the downward facing camera). The ultrasonics used to adjust height but this was only true of the P3 and older Phantoms, not the P4.
I'll again state (as someone is going to nit-pick and call me on it)... ultrasonics will adjust height slightly but only if the Phantom is about 12" off he surface and only if the surface rises slowly and the Phantom is moving slowly. This was changed with the P4 (and Mavic) most likely because of the collision sensors being added.
It is merely a case of the ac not being able to determine where it is or what is below it because it cannot get a good reading from the sensors when below 10 feet over water. This causes it to fly erratically which I and others have experienced and the only cure when over the water is to disable the downward sensors. You can dispute this all you want but I know first hand that this is the case.
There will always be differing opinions in the forums. All I can tell you is my advice is based on numerous flights over water and what we found happening and how we overcame the problems. Like I also said just go over to the DJI forum and ask the same question and you will no undoubtedly get the same answer, even from the DJI techs.
