Patent GB-666391-A (GB)
Title: Improvements relating to fire control systems for guns
IPC: F41G5/00
Filed: 1944-01-07
Abstract: 666,391. Gun fire-control systems. SPERRY GYROSCOPE CO., Inc. Jan. 7, 1944. Jan. 8, 1943] No. 377/44. Class 92 (ii). A gunfire control system comprises apparatus that explores a sector of space and produces on the screen of a cathode ray tube indications representing the positions of objects in that sector, and an aiming device for aiming a gun at an object with means for superposing on the screen of the cathode ray tube an indication of the point within the sector of space at which the aiming device is aimed. As indicated in Fig. 1, the apparatus may include a pair of scanners 1, 1<SP>1</SP>, arranged on an aeroplane either one at the top and the other at the bottom of the fuselage, or one at each side, or again at opposite ends, so that they each explore a different hemisphere. Each scanner is adjustable in azimuth, each has data transmission devices for indicating the azimuth and elevation positions of the scanner, and each has a parabolic reflector 2 which nods and spins, all such apparatus being constructed as in Specification 635,821, [Group XL(c)]. Spiral scanning voltages are produced as in Specification 621,485- the present Specification describes a suitable circuit with reference to Fig. 3 (not shown)- and these voltages, referring to the scanner 1 only appear in leads 26, 27. High frequency energy fed to the scanner 1 is generated by a transmitter 16 which is modulated by a short pulse produced by a trigger 17 and pulser 18 in accordance with the frequency of control oscillator 19. Reflected energy from a target is fed to a receiver 20 through a T-R box 21 and pre-amplifier 22, the T-R box being as described in Specification 610,704, [Group XL(c)], and is applied through an intensifier 23 to the control grid 24 of a cathode ray tube 25. The plates 30, 31, of the tube are in circuit with vertical and horizontal electronic switches 28, 29, connected to the leads 26, 27, which carry the scanning voltages. By this means an indication appears on the screen corresponding to the orientation of the detected object with relation to the spin axis of the scanner1. A gate 33 permits transmission through the receiver only during a short interval succeeding the radiation of a pulse. Range indication is obtained as in Specification 621,485, the range circuit including a wave squarer 35 and a generator 36 which produces a damped oscillating wave which is applied to switch 29 the range being thus indicated by the width of the indication on the screen 32 of tube 25. The other scanner 1<SP>1</SP> has corresponding apparatus associated with it. Aiming device indicating. Sighting instruments 38, 39 are used to direct the guns directly or to supply data to a computer. As shown in Fig. 4 a transmitter 40 (Fig. 1), associated with sighting instrument 38 includes a stator winding 42 supplied with alternating current, rotor windings 44 rotated in accordance with the elevation of the instrument and connected to stator winding 46, and windings 47, displaced by 90 degrees, rotated in accordance with the azimuth of the sighting instrument 1 and connected to rectifiers 48, 49, and associated filter networks. The rectifier voltages are applied to the deflecting plates 30, 31 through switch 28 or 29. The transmitter also includes a cam 50 which controls a switch 52 adapted to transfer the outputs of rectifiers 48, 49, to the switches 28<SP>1</SP>, 29<SP>1</SP>, of the other tube 25<SP>1</SP> associated with scanner 1<SP>1</SP>, thereby an indication of the target appears in the tube corresponding to the hemisphere in which the target is located. The information presented on the screens of the tubes may be repeated on other tubes 70, 70', suitably located, and the traces on all the tubes may have desired characters. Thus, a circular trace may be produced by the provision of an oscillator 75, Fig. 4, coupled to the outputs of rectifiers 48, 49, by transformers 76, 77, a phase shifting network 78 being inserted between the oscillator and one transformer. A straight line trace would be produced by disconnecting transformer 77 from the oscillator. The circuit of Fig. 1 also includes wave squarers and phase adjusters 55, 56, 57, which act to control the switches 28, 29 so as to apply successively to plates 30, 31, voltages corresponding to spiral scanning, position of instrument 38, and position of instrument 39. The switches 28, 29, may be as in U.S.A. Specification 2,146,862.