Patent GB-754530-A (GB)
Title: Improvements in or relating to high frequency electro-magnetic radiating and receiving systems
IPC: F41G5/18
Filed: 1946-09-25
Abstract: 754,530. Gun sighting systems. SPERRY GYROSCOPE CO.. Inc. Sept. 25.1946 [July 20, 1943], No. 28685/46. Class 92 The movements of a gun and the aircraft upon which it is mounted are controlled by a single control device, this device serving (a) to cause a motive means to move the gun angularly to a selected attitude, for instance, towards the predicted future position of a moving target, and (b) to cause power-operated means to move the aircraft angularly towards the same attitude or to an attitude related thereto. In the construction shown light from a source 13 is directed through a reticle 14 on to a fixed mirror 15 which produces a virtual image of the reticle at the intersection of the gimbal axes of a gyroscope rotor 25. A converging lens 16 mounted on the casing of the rotor has its focus coincident with the intersection of the gimbal axes and the pencil of light from lens 16 is deflected by a mirror 17 on to a semitransparent mirror 11 Which can tilt about a horizontal axis in brackets mounted on gear 42 which can rotate about a vertical axis. The target is tracked by keeping it in line with the spot of light on mirror 11, and the spot can be made to move by movements of mirror 11 about its two axis or by causing the pencil of light to move by producing a movement of the rotor 25: Tracking. When a pair of hand-grips 35 are moved about a vertical axis a gear 37 on which they are mounted causes a rotation of gear 42 carrying mirror 11. Gear 37 is also geared to a pulley 64 which, through the medium of springs 66, 67, causes a torque to be applied to the axis 31, 32 of the gyroscope. The latter, therefore, precesses about the vertical axis 27, 28 and the consequential movement of the light reflected by mirror 15 causes a movement to the line of sight through mirror 11 in addition to that caused by the movement of gear 42. These two movements, which together represent the angle between a fixed datum line of the aircraft and the line of sight to the target, are added as shown in a differential 81 and applied to a shaft 87. This shaft serves to produce a corresponding signal in a generator 164 which is connected to the azimuth control 168 of an automatic pilot, the latter including servo-mechanism 171 which controls the movements of the rudder 172 of the aircraft. A predicting mechanism 116 is also supplied with rate data by shaft 115, and with range data by a shaft 126 geared to a knob 18 which, by being adjusted so that it makes the reticle encompass the target, gives the required indication of the range. Range data is also supplied to a ballistic corrector 137 which is supplied also with data corresponding to altitude and air speed by knobs 141, 142. The outputs from mechanisms 116, 137, are combine in a differential 132 whose output shaft 148, representing azimuth lead angle for the aircraft gun 191, positions the stator of a transmitter 194 the rotor of which is positioned by gearing from shaft 87 in accordance with the line of sight to the target. A signal corresponding to the desired positional angle for the gun thus appears in leads 199 and is transmitted to a receiver 201 whose rotor is positioned by shaft 202 in accordance with the azimuth position of the gun. The gun is moved by an azimuth servo motor 211 until the position of its rotor corresponds to that of the transmitter .194. A similar system is provided as shown for tracking the target and positioning the gun in elevation. In a modification (Fig. 2, not shown) a radar system is employed for tracking the target automatically.