I am working on an art installation with three spherical robots that are about 11 inches diameter each. The robots are coated with a 0.3-0.5 inch thick silicon “skin”. They emit colored lights for expressive/aesthetics patterns. We have been using an IMU for orientation but it is simply not reliable on the long run to get an abolute heading as it always ends up drifting (there is no way around it, we would need to get a higher-end IMU costing more than a thousand dollars each). For position in x-y space we currently use a UWB system which is relatively accurate (about 10 cm precision).
We tried many different things are have been unable to find any way to precisely measure the heading of each robot.
I believe it would be feasible to do so if we were able to accurately track infrared emitters coming from each robot, tracked by a ceiling IR camera. We could then equip each robot with two IR emitters each, one on each side of the shaft. By controlling when the robots send an IR signal and measuring the absolute x,y position of the IR signal, we would be able to infer the absolute orientation of each robot on the plane. Only problem I could see is that the IR light would get diffracted by the silicon.
I am wondering if there exists products that could directly support this kind of tracking and/or if by using different products (eg. one ceiling IR cam + some IR LEDs) I could implement this.