GB1253972A - An arrangement for generating an electric control signal for correcting the elevation of a gun aimed at a target - Google Patents

Abstract

1,253,972. Ballistic analogue computers. AGA A.B. 4 Oct., 1968 [13 Oct., 1967], No. 47127/68. Heading G4G. Apparatus for generating voltage representing correction applied to the elevation of a gun in response to at least one factor influencing ballistic properties of the projectile comprises (Fig. 1) a series CR circuit 1, 2 and switching FET 4 energizedfrom voltage U 1 representing ballistic factors; e.g. type of ammunition, muzzle velocity, atmospheric pressure and temperature, temperature of propellant; generated by an operational amplifier responsive to input direct voltages respectively proportional to the respective factors. A pulsed control voltage L 1 (Fig. 2) over resistance 6 periodically closes the FET, and immediately prior to each closure a pulsed control voltage L 2 closes a switching FET 8 to discharge capacitor 2; the control voltages being derived from a logical circuit. Application of U 1 at time t = 0 charges the capacitor 2 progressively to voltage U C which is applied over operational amplifier 9 to operational amplifier 10 for comparison with voltage U X proportional to target range, for equality at t = t 1 , when a pulse U 10 is generated whose duration t 1 represents the ballistic correction, which may be converted by integrator 12 into corresponding voltage U 12 . Further ballistic corrections may be introduced by adding series RC circuit 14, 15 and FET circuit 17 switched by pulsed voltage L 1 in circuit with reference voltage U 2 , derived similarly to U 1 and representing further ballistic factors; capacitor 15 being similarly predischarged by L 2 and the charged capacitor voltage being added to that of capacitor 2 at the input of 9. A modification is described (Fig. 3, not shown) wherein a correction voltage for parallax between range-finder and gun position may be generated by instantaneously charging a capacitor at time t 0 from a voltage representing distance between gun and range-finder, over a switching FET closed by control voltage L 2 , and partially discharging the capacitor over a resistance and further switching FET closed by control voltage L 1 and re-opened at time (t 0 -t 2 ) corresponding to the target range, to disconnect the discharge circuit. The residual capacitor voltage then represents the required lateral correction for the gun.