GB913368A - Improvements in or relating to apparatus for photographing targets and missiles - Google Patents

Abstract

913,368. Pulse radar. ALBISWERK ZURICH A.G. Oct. 22, 1959 [Oct. 22, 1958], No. 35861/59. Class 40 (7). Apparatus for photographing a target and a missile includes radar means for measuring the distances between the camera and the target and the target and the missile, and means for releasing the camera shutter when the distance-difference is less than a predetermined amount. A synchronizing pulse generator triggers pulse transmitter 2, Fig. 4, which feeds aerial 5 via duplexer 3; reference voltages from aerial unit 4 are compared in known manner with the modulation voltage impressed on the video signal in receiver amplifier 8 due to conical beam scanning so that the aerial automatically follows the target. The video signal is fed also to a distance discriminator 9 together with the output of distance gate pulse generator 14, the latter being fed from phase shifter 13, and an error voltage from discriminator 9 is fed back to the phase shifter. In control stage 10 the distance gate pulses cause the a.g.c. applied to i.f. amplifier 7 to become effective only when target echoes occur. Aerial 18 is directed to the expected target position and is fed from transmitter 2; missile echo video output from unit 21 is fed to display 12 and to coincidence circuit 23 the other input to which arrives from distance gate 22 provided for selecting missile echoes to the exclusion of others and preceding the gate in unit 14 by a fixed interval corresponding to an equation derived from the geometry of the problem, Figs. 1 and 2 (neither shown). On coincidence in circuit 23 the camera shutter is released. Phase-shifter 13 comprises a phantastron, a blocking oscillator and a delay line in series, Figs. 7 and 8 (neither shown). Coincidence circuit 23 includes a gate 112, Fig. 9, fed with missile echoes, Fig. 10, a, and distance gate circuit 22 output, Fig. 10, b, to generate pulses, Fig. 10, c, then lengthened in circuit 113, Fig. 10, d. The latter pulses, together with the output, Fig. 10, e, of a blocking oscillator 116 which is triggered by circuit 22 output after delay in line 117, are fed to a " box-car " circuit 115 which forms waveform, Fig. 10, f; the latter is integrated Fig. 10, g, by circuit 119 before application to a Schmitt trigger 120, Fig. 10, h, which actuates a relay 121, Fig. 10, i, controlling an electromagnetic camera shutter-release mechanism. In a modification, account is taken of the relative velocity of the target and missile as calculated by a known device fed with target and missile velocities, the target velocity being determined by known means from the targettracking radar data and the missile velocity being obtained from ballistic data and missile position, Figs. 5, 11 and 12 (not shown). In a further arrangement, the missile fire direction is the same as the line to the target and a single transmitter and aerial are used, Figs. 3 and 6 (neither shown).