Hello all,

How do I turn off the VPS? The vertical altitude measuring cameras/sonars under the P4? I can't find the option in the app to turn this off, I do find the Obstacle Avoidance system (the two front facing cameras) - but I can't find any options for the VPS.


Before you ask why I want to do that: When I fly over water, snow, glass roof, and when landing on my (green 'grass') terrase carpet. Ohh, and I would also like to see if it is the VPS causing my P4 to drop in altitude (1-2 meters) every time I let go of the stick. It stops, hover while descending 1-2 meters...then stabilize in a perfect hover (but lost 1-2 meter altitude).

This forum has a powerful search feature.  Use it.

boxerman Posted at 2016-3-22 16:25
This forum has a powerful search feature.  Use it.

Smart ass reply, uhh? Several previous posts have asked this question, no answers. Perhaps a DJI moderator need to answer this. Boxerman, if you don't want to help, don't click the reply button.  

Thacyoon Posted at 2016-3-22 12:04
Smart ass reply, uhh? Several previous posts have asked this question, no answers. Perhaps a DJI m ...

Ok.                        

With the P4 there is no ON/OFF switch of the VPS. In P and S mode it is on, in ATTI mode the VPS only detects altitude and there's no position hold.
And the P4 should not drop in altitude when you let go of the stick.
Do a IMU and compass calibration (flat surface) and see if it still persists.

DJI-Ken Posted at 2016-3-22 18:42
With the P4 there is no ON/OFF switch of the VPS. In P and S mode it is on, in ATTI mode the VPS onl ...

Thanks for the reply. Won't the VPS system be confused when flying low over water or snow? Regarding altitude drop have many P4 owners reported this. There are several posts/threads at Phantom Pilots regarding this. Yes I have calibrated the IMU's on a perfectly level surface, including gimbal and compass (at flying location)

I raised this issue as well. The loss of altitude when stopping is highly annoying and may result in inadvertent crashes. It makes low altitude flying a bit dicey..

Also, the Object Avoidance stopping distance to objects is extremely close..makes me uncomfortable.

The DJI engineers hopped on the thread and said they are looking into it. Hopefully the loss of altitude issue will be addressed in the next firmware update.

microcyb Posted at 2016-3-22 19:39
Well, Flying low will be an issue, but water should not be a concern since it is a flat surface are ...

Your post and fancy images describe the Object Avoidance system. Sorry, but please, I am talking about the VPS.

waynepj3@gmail. Posted at 2016-3-22 19:47
I raised this issue as well. The loss of altitude when stopping is highly annoying and may result in ...

Right, you know what this is, thanks.

microcyb Posted at 2016-3-22 19:54
Doubt they can correct low flying without having to set a limiter.  The lower you go, the more the ...

Sorry, your arguments make no sence...

I am seeing the same issue you are. Tonight I did a IMU calibration and a sensor calibration in the assistant app. I am hoping that takes care of the issue I will post results tomorrow.

stussyredhat@st Posted at 2016-3-23 06:22
I am seeing the same issue you are. Tonight I did a IMU calibration and a sensor calibration in the  ...

Ok, thanks man

Well it made a big difference!!! I had no drop at all after doing the calibration in the assistant app!

stussyredhat@st Posted at 2016-3-23 20:15
Well it made a big difference!!! I had no drop at all after doing the calibration in the assistant a ...

Ok, thanks for the feedback. I have tried several IMU calibrations on a perfectly level surface...but no joy

I've done a cold IMU calibration and still having the altitude drop when the stick is released. Very annoying and if im not correcting immediately, I can see it causing a crash when flying low altitudes. But when it does hover, she's rock solid so I'm thinking it has something to do with the firmware. Hopefully it will be resolved before a crash.

DJI-Ken Posted at 2016-3-22 13:42
With the P4 there is no ON/OFF switch of the VPS. In P and S mode it is on, in ATTI mode the VPS onl ...

I seem to remember seeing several people advise turning off VPS when flying over water, snow, or anything else that has no discernible pattern. That was several months ago, with regard to the P3A/P.
I believe that this was in response to someone complaining about a lack of control/ loss issue when flying over water.
Since my P3S had no VPS, I didn't really pay much attention at the time.
The P4 manual mentions that in these situations VPS does not function properly, which is understandable. However, will the fact that it does not function properly in these situations adversely affect control when flying low over water?

DJI-Ken Posted at 2016-3-22 12:42
With the P4 there is no ON/OFF switch of the VPS. In P and S mode it is on, in ATTI mode the VPS onl ...

DJI-Ken,

Could you also look into the issue I reported on in a separate thread about the P4 not adjusting its altitude up and down (closely tracking vhanges in ground elevation) when flying low (in VPS range) over uneven ground?  My P3Pro does this, but my P4 does not, which makes flying low much riskier.

david.p.mann@ea Posted at 2016-3-30 00:33
DJI-Ken,

Could you also look into the issue I reported on in a separate thread about the P4 not a ...

This is how the system operates and tells it's limitations.
if you are experiencing issues and it is not described in the screen shot, then I can have someone contact you and you can send the uint in.

TK-421 Posted at 2016-3-30 01:08
Ken, I'm pretty sure you can't answer this, but have you heard any word on whether or not we'll be ...

I have sent an email to HQ inquiring about it.

So , until we are not able to turn the VPS off, we are not able to fly safely above water or reflective surfaces with the P4 ?

Thats a real disadvantage compared to the P3A/P !

DJI-Ken Posted at 2016-3-29 10:40
This is how the system operates and tells it's limitations.
if you are experiencing issues and it i ...

So basically you can only fly over water 10 meters above it in GPS mode or switch to ATTI mode now? That's ridiculous. It stops for bison, but can't fly over water??

DJI-Ken Posted at 2016-3-29 11:40
This is how the system operates and tells it's limitations.
if you are experiencing issues and it i ...

DJI-Ken,

I'm sorry - I guess I'm not making myself clear.  The VPS system on my P4 is working at low flight levels.  It is accurately and continuously reporting the distance between the bottom of the P4 and the ground.  It is the flight control logic on the P4 that is behaving differently than on my P3Prol.  At low levels (<10 feet above ground level), if I fly over a small valley (e.g., a ditch), the P3Pro will maintain it distance from the ground as I fly slowly over the ditch - the P3Pro will descend as it flys over the downhill side of the ditch and then it will ascend as it flys over the uphill side of the ditch keeping the distance between the P3Pro and the ground constant.  On my P4, when I fly over the same ditch, the P4 does not descend when flying over the downhill side of the ditch nor will it ascend as it flys over the uphill side of the ditch.  Instead, the P4 stays at exactly at the same barometric altitude.  Similarly, if the P3Pro is 2 feet above the ground and then flys slowly over a mound of dirt two feet high in the center, the P3Pro will increase its altitude automatically until it is 4 feet high when directly over the peak of the mound (thus, maintaining a two foot distance between the P3Pro and the ground at all times.  My P4, on the other hand, will not change its height and will barely clear the mound (or run into it) if obstacle avoidance is turned OFF.  If obstacle avoidance is turned ON, the P4 will usually stop before hitting the mound, which is great.  However, I would prefer that the P4 change its altitude in response to changes in ground elevation like my P3Pro does, especially when Obstacle Avoidance is turned OFF.

Was this change in flight behavior of the P4 vs. the P3Pro during low level flight when VPS system is functional an intentional change?

Am I making myself clear now?

david.p.mann@ea Posted at 2016-3-30 08:56
DJI-Ken,

I'm sorry - I guess I'm not making myself clear.  The VPS system on my P4 is working at  ...

OK, I see exactly now.
I'll send an email and see what they say.