Patent GB-590489-A (GB)
Title: Improvements in or relating to gunfire control systems
IPC: G01S13/66
Filed: 1944-11-10
Abstract: 590,489. Radiolocation. STANDARD TELEPHONES & CABLES, Ltd. Nov. 10, 1944, No. 22224. Convention date, Aug. 22, 1942. [Class 40 (v)] [Also in Group XXI] A gun fire control system comprises means for transmitting electromagnetic impulses for detecting aircraft and detonatable projectiles fired at such aircraft, means for receiving reflection pulses, means for indicating the reflection pulses of a selected aircraft and a projectile so that their relative positions can be observed, and detonation control means under the control of an operator to effect transmission of detonating impulses to effect detonation of the projectile when the reflection pulses indicate close proximity of the projectile and the aircraft. As shown in Fig. 1, the system comprises an obstacle detection device 10 having a transmitting antenna 12 and receiving antennµ 14-17, coupled respectively to a transmitter T and receiver R. The transmitter is provided with a source E of carrier energy and impulse generators F1 F2, controlled by a switching device S. The receiver R is associated with a panoramic oscillograph having a wide range for detecting the presence of enemy aircraft and a plurality of vernier oscillographs, such as the one 20 shown. The system also includes a saw-tooth generator SG for the oscillograph 20, a time base control 32 to provide a reference point 22 on the oscillograph to follow the reflection pulse 30 of the aircraft, a motor 41 for the antennµ for lookout scanning, and hand wheels 44, 45 for following the target in azimuth and elevation when an obstacle is indicated, the movements of these hand wheels as well as of those of control 32 being also transmitted to the gunstation 25. General operation.-In use the motor 41 is de-energized once an enemy aircraft 31 is indicated on the oscillograph and the hand wheels 44, 45 then actuated to maintain maximum reflection pulses of the aircraft, and the control 32 is operated to keep the reference 22 in correspondence with reflection pulse 30. When the aircraft comes within range, a shell is fired, this shell giving an indication 50 on the oscillograph. When the indications 50 and 31 of the shell and aircraft respectively coincide or nearly coincide, the operator actuates a switch 49 to switch over from generator F1, which transmits impulses at a frequency of 60 cycles per second, to generator F2 whose frequency is 30,000 cycles per second. The increased energy thus transmitted serves to detonate the shell in the vicinity of the aircraft. Projectile.-As shown in Figs. 2 and 3, each projectile comprises a body 52 containing an explosive charge 53 and having an end compartment containing a fuze controlling circuit 55 whose fuze 56 extends into the charge 53. The circuit includes a charged condenser 58, a gas-filled discharge tube 60, a lead 62 connecting tube 60 with the projectile body and a lead 61 connecting the tube with a normally coiled antenna 65. The latter is' arranged near an insulating well 66 through which passes a coupling 67 between the antenna and the tube 60. The projectile also contains a small arming fuze 68, 'as disclosed in Specification 578,153, [Group XXI], the timing of this fuze, details of which are given in Fig. 4 (not shown), being effected by a coil 74, Fig. 1, surrounding the gun barrel and in circuit with a variable resistance 76 and current source 75. In operation, the arming fuze 68 detonates only when the projectile reaches a predetermined range, as indicated at 69, Fig. 1. On detonation, the antenna streamer or streamers trail behind the projectile thus enabling the projectile to be detected' more easily and also increasing its receiving capacity for the impulses from generator 52. In Fig. 5 (not shown), a modified fuze controlling circuit is given for projectiles not equipped with an arming fuze 68. Such circuit includes a coil tuned to the detonating impulses sent, out by the transmitter T. Detonation control apparatus.-Instead of actuating the switch 49 for detonation purposes, the operator may operate a handle 122, Fig. 9, to cause a pointer 120 to follow the target indication 30. Rigidly connected to the pointer by an adjustable device 123 is a light-transmitting rod 126. When the shell pulse 50 reaches the rod 126, the light therefrom passes through the rod and actuates a photo-electric cell 125 which is connected to the grid of a gas discharge tube 131. A surge flow then passes through the tube to switching device S to bring frequency source F2 into operation to detonate the projectile. In an alternative semi-automatic arrangement, the reference pulse 22, Fig. 1, replaces the pointer 120 and the movements of the cell 125 are controlled. by manipulation of the control 32. In a further modification, Fig. 10 (not shown), two pointers are used, one to follow the target indication and the other the projectile indication. These pointers engage and slide over a common resistance, the pointers, resistance, a variable resistance and an energy source being in circuit with an electromagnetic 'coil. When the pointers are at a predetermined position apart, the coil causes a switching device to snap over, thereby actuating the switch S.