GB908031A - Improvements in or relating to radar simulation apparatus - Google Patents

Abstract

908,031. Radar simulators. COMMUNICATIONS PATENTS Ltd. Aug. 16, 1960 [Sept. 10, 1959], No. 30889/59. Class 40 (7). A radar simulator capable of simulating the effect of " window " comprises a C.R.T. 10 providing a P.P.I. raster on its fluorescent screen which is focused on to a photo-multiplier 13 through two spaced sheets of light polarizing material; e.g. " Polaroid " (Registered Trade Mark), arranged with their respective axes of polarization at right-angles, a dispenser 32 being located between the Polaroid sheets 22 and 23 for releasing on to the lower Polaroid sheet 23 particles of " light-active " material capable of rotating the plane of polarization of light incident thereon from the screen of the C.R.T. 10 so that each particle causes some light to pass through the lower Polaroid sheet 23 on to the photo-multiplier 13 to produce a corresponding electrical signal which is applied to a display C.R.T. 12 scanned synchronously with the C.R.T. 10. The " light-active " material may comprise caster sugar, finely-ground quartz, fine river sand or finely-divided mica flakes. For simulating a radar carried by a fighter aircraft intercepting a target dropping the window, the C.R.T. 10 together with the upper Polaroid sheet 22 and a lens 18 and filter 37 are moved by a gantry 20 in accordance with the assumed movement of the fighter, the scanning coils 9 of the C.R.T. 10 being orientated by a motor 29 in accordance with the assumed heading of the fighter, and the dispenser 32 is moved by a gantry 30 in accordance with the assumed movement of the target. A target image is produced by a quartz crystal (not shown) carried by the target gantry adjacent the dispenser 32. The dispenser 32 is operated to release the " light-active " particles by rotation of a shaft 33 controlled by a " window release " relay 35. Disposal of the window after release is simulated by vibrating the lower Polaroid sheet 23 by a vibrator unit 24 and wind drift is simulated by tilting the sheet 23 about orthogonal axis by means of motors 65 and 71.