Abstract: A radiation mast such as a periscope has a head end 10 incorporating a radiation receiver in the form of a top mirror 12, the lower end 11 of the mast being physically separated by a considerable distance from end 10 and being provided with an information station, for example, in the form of viewing optics (E) and/or a video monitor 17. The radiation image formed at the receiver 12 is viewed at the information station in accurate superimposition with a reference pattern which is electronically generated by generator 19 and which is stabilized in space with respect to at least pitch, roll and yaw movements of the vehicle on which the mast is mounted. The pattern is also stabilized with respect to such disturbance factors as are effective on the information relaying means, for example, optics in path B, C, D, whereby the radiation image can be visually referenced to the electronically generated pattern, unwanted relative movements having been eliminated.

Abstract: In a system (10) comprising a trunnion-mounted aiming device (11) and a trunnion-mounted sighting device (14) interconnected by a tracking link (13) and having an associated visual display (16) providing an image of the field of view containing the sight line (15) of the sighting device (14) there is provided a means of accurately positioning an aiming mark designating the pointing direction (12) of the aimed device (11) in the visual display (16). This positioning arrangement is provided by an elevation sensor (18) associated with the aimed device (11), an elevation sensor (19) associated with the sighting device (14), an electronic indicator mark generator (28) and an electronic processor (20), the latter being operable according to the measurements from the sensors (18,19) to deflect the mark generated by the generator (28) so as to compensate in the elevation axis for backlash and inertia of the link (13) and in the traverse axis for lack of parallelism of the trunnion mountings of the devices (11,14).

Abstract: An optical scanning system comprises a raster scan imager mounted on a support which is rotatable in azimuth, the imager being arranged to provide a line scan which is substantially coplanar with the azimuthal rotational axis and a frame scan which is orthogonal to the line scan, a sensor is provided for monitoring azimuthal rotational rate of the support and a frame scan control means is coupled to the sensor and arranged to provide that the frame scan rate at a field of view is constant and corresponds to a standard T.V. field scan rate irrespective of the azimuthal rotational rate.