Question Arkit with Unity better positioning on long distance

I would like to use Arkit and Unity for an AR guided tour of our city, where every person will see a series of videos anchored in space, and the tour guide will give more info and context.

I have a demo, made in Unity where first u go around placing cubes, to be used as placeholder for the videos. This works very well in small enviroments like an office or a home.

But when we try this solutions on the actual place, the cube are placed fine, but when going back to the starting point i have noticed that the camera in Unity is not at the starting point. So the cubes are not aligned with the actual real places. It look likes there are some errors accumulating that will make the real position differ from the one in Unity.

I am not sure how to solve this problem, i can’t find any similar problem on the forum. Could this be solved by software ? Is this an expected behaviour ? maybe it has a max range. Could it be a problem with Unity and the distance from the origin ? I don’t think this is the case, but maybe it starts to loose the origin ?

I am using an Ipad Pro to make the tests, but for the client it would use an Ipad 10'' Thanks

 

Sounds like Lightship ARDK using VPS would be perfect

 

In my opinion, aside from ARKit you can try what Mr. DevDunk has said.
I have seen the website, it looks really cool how Lightship does.
Be noted that the VPS (visual positioning system) feature of Lightship still not globally implemented.
Unlike GPS, only certain part of earth are covered, (it can be looked on their website).

To answer your curiosity, ARKit does the drift!
Drift means to be happened the world position will moving away from where it should be.
This will affecting the position of virtual objects, where we put on the AR world.
Currently, based on Apple world tracking documentation, it will drift much further if move really far from where we start.
I can't confirm if this also happens in ARCore, but I do believe current AR solutions will likely have this problem.
So, each of them implement their own solution to counter this problem, as like the Lightship does.

You can try another notable AR SDK and see which is better suit for your case, in ARKit currently, I think no

Yes

I don't know about the max range, as far I experienced, around 1 ~ 2 meters it starts drift about 5 ~ 10 cm, and more it will be.

Yes it is. Since you said when you going back to the original position, the AR object is moving (not on the desired position), it happens the world origin is moving.

 

You can make private vps scans as well. Those are verified quickly and will be for your app only. You can also make a public scan while you're at it so that area will be supported for everyone

 

That's quite interesting.
Probably would try it someday. Thanks for the information!

 

Thanks DevDunk, Lightship ARDK using VPS seems to be a valid solution for my problem but at the moment i can't use that cause it doesn't support neither Nreal glasses or Ipads.

 

My initial idea was to split the tour, changing the ogirin along the way, based on what you said, in this way it should reduce the drift beacuse the starting origin is always closer to where the users are. Now i am wondering if changing the Scene will make this "reset" possible.

 

iPads are not officially supported, but I have used them with lightship for like half a year and it works fine. IOS runs ARKit as wel

 

Thanks Do you know if i can use the VPS service offline, meaning with no connection ?

 

I do not think that's possible, but not sure. I suggest asking on the ligthship discord or forums

 

You're right about the closer to the world origin to the device, it "can" make the tracking accuracy better
But by this, we have to, or the system I must say, recalculate again the position of virtual 3D object in AR
Since the idea will change the world coordinate origin, make it closer to the user, whenever he stand
The system should know again where the actual previous position of where you want to put the AR object

For example:
- we put in corner of the desk
- system will tell you, from the current world origin, it is on (x,y,z)
- then the user moves, and the idea is the world also being moved closer to the user
- by this, "the corner of the desk" is no longer (x,y,z)
- the system should calculate again (a,b,c) which is as same as previous (x,y,z)

I think this is simple analogy, please let me know if I made a mistake
If you can use the VPS solution, it will very great as long it able to solve the problem