Multiple point relational sensors

Hey Folks, I am new to the forum. Thanks for having me! I am also fairly new to tech so pleas bear with me.

I am working on a project and I am not sure if the technology I need exits. I am hoping you can point me in the right direction.

I have attached a photo which will diagram what i am explaining.

Basically I need a sensor (POINT A) that is aware of its relationship to beacons (POINTS B, C, and D). If B, C, and D are moved A is aware of, and measuring, the change in relationship. This represented by the orange lines. The orange lines are essential digital strings that attach the beacons to the sensor. The sensor at least needs to read the distance of each beacon, but ideally reads the angle as well. perhaps is a digital line is drawn ( depicted in purple on the second diagram) as a line to measure the angle against.

This would all happen on a single plain. Imagine B, C, and D are all marbles on a table with beacons in them, and a is sitting on the table as well.

Accuracy is very important, down to the mm. Pinpoint is ideal.

Dose a technology like this exist at all?

Thanks for the help folks.

have attached a photo which will diagram what i am explaining.

No you have not.

Dose a technology like this exist at all?

Basically no, not to the accuracy you are looking for.

Yeah guess I cant seem to get the url to work... working on it.

No you have not.
Basically no, not to the accuracy you are looking for.

Curious, what kind of accuracy can I get?

Hard to say with so little information. Like what type of beacons are these?
I think the best system will only give you something like 20cm.

Like what type of beacons are these?

Anything that can be read in relation to the sensor. Suppose that is what I am asking... Cause i am not sure what could be used.

Also curious. What if there were multiple sensors like point A, like 3 maybe, that could be used to triangulate B, C, D. Would something like this be more accurate?

'beacons' means nothing. Is this on a tabletop? On a football field? Attached to people? Caterpillars?
If it's a tabletop, simplest would be to use a camera solution, which means not Arduino.

This is the best system their is at the moment for this sort of thing. it is not cheap.

Laser range finders can get millimetre accuracies (or better), but you must have a line of sight between the reference beacons and your object, and they would have to be pointed accurately at each other. They're much bigger than marble size, by the way. Distance is measured by timing the round trip of laser pulses between the beacon and your object, accuracy depends on the quality of this timing. Going sub-mm will be very expensive.

Stuff like millimetre wave radio beacons can't get that kind of accuracy (theoretic minimum resolution is one wavelength).

On top of that you would have to know the relative locations of the reference beacons to at least the same accuracy, as all inaccuracies add up in your final location accuracy. Same for the location of your radio antenna or the laser reflectors within the object you're trying to locate.

So I believe in theory this is possible, maybe even in practice, but it's not a simple hobby/diy type of project.