A motion tracking system configured to determine a rendering of a simulation object representing a real object (1) in a real environment (5, 6, 7, 8, 9), the positioning system comprising: an imaging device (24) mounted to the real object and configured to capture a series of images of a plurality of irregularly positioned markers (30) located in the real environment; an image processing unit communicatively coupled to the imaging device for receiving the series of images; the image processing unit being configured to determine the real location of the real object by: creating a three-dimensional model of a constellation formed by the markers visible in the series of images; and mapping the patterns of markers visible in successive images captured by the imaging device to the model and thereby determining the motion of the imaging device relative to the markers; and to determine the rendering of the simulation object so that the rendering mimics the determined motion of the imaging device.