When I get my P3, I want to fly it without GPS, a few feet over a tarp or blanket with a pattern, then drag the tarp around to see if it follows.  

If the vision positioning works as described, I think it should follow the blanket as it's dragged around, including yaw.  That would be cool to see.

Just sharing thought because I don't have anything else to do drone-wise until my P2 is fixed or my P3 arrives.

EDIT:
Here's an experiment I DON'T wanna do... Use it inside a church to film a wedding.  That little scene in their promo video was a little over the top.  Grandma in the second row would surely freak out, and nobody would be watching the happy couple as they listen to the buzzing bees.  I think there was a scene in a boxing arena too.  That won't happen.

I'm curious how this works, too. Also wondering how it works if the ground isn't... static. Like rippling water. I assume it only calculates distance and relies on gps for positioning rather than what's down below.

i am curious why the pattern recognition only works up to 10 feet...

I assume it will follow the blanket.

And what happenes when you fly over water with wind ripples?  Will it follow the pattern of waves or ripples in the water?

Fly it directly over a slow moving vehicle with a patterned top maybe?  Hmmm.

Rothgarr Posted at 2015-4-21 02:24
I'm curious how this works, too. Also wondering how it works if the ground isn't... static. Like rip ...

Sorry to barge in on your topic - but think it relevant to subject .... but .....
P2 V+ Newbie here - so forgive me if this seems a dumb question regards P3!
You apparently cannot turn-off the vision positioning system on P3 - so if you fly low across a field (less than 6ft? where the VP may be monitoring) which then drops away (cliff edge) rapidly - (thinking of Beachy Head in UK) - will the Phantom, when it goes over cliff edge, suddenly drop out the sky trying to re-engage a 6ft above ground flight level??

Yes, but not until it looks down.  As illustrated in the linked video, which accurately reflects the laws of physics.



Okay, truth is, I don't know and all of the following is guesswork.  I would think if it has GPS lock, it would use that to determine altitude.  Lacking that, if the altitude per its ground sensors is greater than (however many) feet and it has no GPS or other way to determine altitude, I would think it would fly just as any would without GPS... Essentially, just Atti mode.  (Stable horizontally, but drifting with the wind and momentum.)

More relevant, perhaps, is what it would do when flying low over a picnic table, or over a table indoors.

paul@westpointd Posted at 2015-4-21 05:03
Yes, but not until it looks down.  As illustrated in the linked video, which accurately reflects the ...

Thanks Paul - I enjoyed the video and that was exactly my concern!!
As for flying over picnic tables etc - I had read some previous post that suggested that would be an issue - someone had experienced real problem flying over a graveyard where the P3 kept bobbing up and down between headstones!! - Which is what prompted my concern with a cliff edge!!

My guess would be , it won't follow it, this feature is designed to make steady by fining a fixed target and position on it, now if the target moves this might confuse the logic board and probably (guessing again) tries to look for the next fixed target and would probably remain unstable until then,  but it would definitely be interesting to find out out the result of your experiment, make sure you tape it

The vision positioning system won't work over water unless you can find water with "a surface with clear pattern and adequate lighting".
The P3 flying past a cliff edge will continue to fly normally using the barometric altimeter to maintain level - just like it does in almost every flight.  
Phantoms do not get any altitude information from GPS.

Most likely in a wedding you wouldn't do the actual wedding you would set it up like a photo shoot but just replay a short version of it for the aerial shots.

labroides@yahoo Posted at 2015-4-21 07:49
The vision positioning system won't work over water unless you can find water with "a surface with c ...

"Phantoms do not get any altitude information from GPS."

I stand corrected.  I really thought they did.  I looked it up and confirmed GPS is capable of providing altitude data so I wonder why it isn't used that way.

GPS accuracy is fine for horizontal position but much less accurate for altitude (that's all to do with the complicated geometry involved in GPS calculations).  You wouldn't want GPS altitude, it can be +/- 100 feet or more.  Easy to check this with a handheld GPS (if it doesn't have a barometric sensor).
Barometric altitude is far superior.
Read more here:
https://support.garmin.com/suppo ... /case.faces?caseId={66f1b0a0-4cd6-11dc-4733-000000000000}

labroides@yahoo Posted at 2015-4-21 10:58
GPS accuracy is fine for horizontal position but much less accurate for altitude (that's all to do w ...

Your link....she no work.  

Here's the text
        How accurate is the GPS elevation reading?
GPS heights are based on an ellipsoid (a mathematical representation of the earth's shape), while USGS map elevations are based on a vertical datum tied to the geoid (or what is commonly called mean sea level). Basically, they are two different systems, although they have a relationship that has been modeled.

The main source of error has to do with the arrangement of the satellite configurations during fix determinations. The earth blocks out satellites needed to get a good quality vertical measurement. Once the vertical datum is taken into account, the accuracy permitted by geometry considerations remains less than that of horizontal positions. It is not uncommon for satellite heights to be off from map elevations by +/- 400 ft. Use these values with caution when navigating.

It occurred to me that if this works, I could use a rope to drag a large piece of marked cardboard behind me, flying above it 10 feet would be the "follow me" feature of the Phantom 3.

  ;-)

Eric Cheng posted a video "Fooling the DJI Phantom 3 Visual Positioning System (VPS)" about this on his channel 7 hours ago!

I personaly tried that with a Parrot Bebop. Yep, it will follow the carpet. ;)

However, there is an intrinsic problem with camera position tracking indoors when there is strong lighting form above, which I have encountered on the Bebop and the AR Drone 2: they tend to track their shadow, and guess what happens ? Yep you got it ... slams into the wall attempting to follow itself.

Other than that, works great. If you pay attention to lighting conditions it's probably going to work well.

chefobi@gmail.c Posted at 2015-4-25 14:13
Eric Cheng posted a video "Fooling the DJI Phantom 3 Visual Positioning System (VPS)" about this on  ...

Cool!  I guess it's still using the compass, so that's why yaw doesn't follow.

I wish there was a way to look through the bottom camera via Lighbridge.  I know I could turn the normal camera down, but a "quick glimpse down" with a button might be a handy feature for landing, even while the regular camera is recording.  I don't know if it's a black and white sensor, etc and no clue what its resolution is.