A method of, and apparatus for. furnishing information to determine the position of a body

摘要

To determine two positional co-ordinates, of a point (D) within a space, a beam (10) a radiation is caused to illuminate a part of the space and is deflected cylindrically over the space, the beam being modulated in phase with the cyclical movement such that the radiation incident upon the point (D) includes enough information to identify the point. Embodiments with rotational (r, &thetas;) and Cartesian (x, y) co-ordinate axes are disclosed.