Object tracking

Hullo people. I'm thinking of developing a project which requires an object to be tracked around a room in 3D, to within an accuracy of within about 30 cm. I'm not talking about image processing or a video feed, just some way of determining an object's location, through perhaps some form of triangulation? Curious of any ideas/thoughts. Thanks in advance :)

Have a look: http://coolarduino.wordpress.com/2014/08/20/ultrasonic-3d-radar/