Why do you want to avoid computer vision ? If the space is unobstructed and the objects are visually distinctive it should be fairly easy to do this with a pai

Why do you want to avoid computer vision ? If the space is unobstructed and the objects are visually distinctive it should be fairly easy to do this with a pair of cameras with known position and orientation. 100 Hz is pretty fast but that's mostly a question of how much processing power you're able to throw at the problem. I've done some work with 3D object tracking. If you'd like to discuss this further my contact info is in my profile.