Abstract: A balance device comprises first, second and third components. The first, second and third components include substantially cylindrical first, second and third central portions, respectively, and which are coaxial with one another. The balance device further comprises a first set of connectors for coupling the first component to the third component and a second set of connectors for coupling the second component to the third component. The connectors accommodate axial movement in response to relative axial forces between the first and second components and minimise rotational movement about the axial direction in response to relative axial torque between the first and second components.

Abstract: A method of co-ordinate registration for Over-the-Horizon Radar comprising he steps of generating a geographic auto correlation function to determine one or more geographic beacons in a coverage area of the Over-the-Horizon Radar, the auto correlation function being in polar co-ordinates, comparing the return radar signal with the geographical map of the coverage area in the general region of the one or more geographic beacons and finding the best fit of the geographic map with return radar signal to enable registration of co-ordinates of the return radar signal. The auto correlation function indicates the amount of correlation between a neighbourhood and a slight displacement from that neighbourhood. A geographic beacon is an area in which there is a substantial difference between the neighbourhood and its surroundings thereby producing a low auto correlation function.