GB1154882A - Image Motion Stabilization System - Google Patents

Abstract

1,154,882. Sight. ITEK CORP. 8 June, 1966 [8 June, 1965], No. 57503/68. Divided out of 1,154,881. Heading F3C. [Also in Division H4] A fire control system employs photosensitive means (e.g. an image converter or image intensifier tube) carried by the barrel of a weapon to produce an image of a target together with image deflection means supplied from sensors responsive to motion of the photo-sensitive means to provide signals which deflect the image in a direction to cancel motion of the latter caused by motion of the photosensitive means and which operate means for firing the weapon when the displacement of the axis of the barrel from the target axis due to such motion is within pre-determined limits. The invention is described in connection with stabilizing the image in the eyepiece of a telescopic rifle sight (Fig. 3), against random angular motion of the weapons about the optical axis. The sensors, which provide signals indicative of the sign and magnitude of motion (i.e. instantaneous position) in rectangular co-ordinate directions X, Y, comprise rate gyros with associated integrating amplifiers. In the basic arrangement of Fig. 1, resistors 15 and 20 are shunted across the integrating capacitors of the integrating amplifiers 16, 19 to prevent the image deflecting means from responding to signals (of about 2 c.p.s.) produced by slow panning. In operation the criterion for "on-target" is zero output from the X and Y integrating amplifiers. Such conditions when sensed by respective trigger amplifiers 67, 69 (Fig. 4), each having the response of Fig. 5, provide the two inputs to an AND gate 78, which if not inhibited by an input on line 88, operates a trigger solenoid 71 to fire the weapon. Such inhibition is effected when the rifle is swung from right-to-left or vice-versa with a velocity exceeding a pre-determined amount by the circuit of Fig. 7 comprising clippers 83, 84 providing signals representative of such motion and controlling respective multivibrators 86, 89 which supply inputs to an OR gate 87 whose output is connected to the inhibit line 88. The arrangement of Fig. 7 may be duplicated for inhibition in respect of vertical motion. The gate 78 may be further inhibited by means of a switch 94 which when closed supplies a positive inhibiting potential to line 88 from the metallic rifle frame portion 96 until a predetermined minimum pressure is applied to the trigger 93 to interrupt the inhibiting potential by the open. ing of contact 99. As the latter contact opens a second contact 100 closes and via a closed switch 95 linked to switch 94 energizes relay 105 which operates to disconnect the resistor 91 shunting the integrating amplifier capacitor and thus allow the deflection control circuitry to respond to panning so that automatic firing of the rifle when the sights are off target is prevented. A further contact may be provided which, when the trigger is pulled back to its extreme position, allows over-riding of all the circuitry and manual (via the electrically controlled trigger solenoid) firing of the rifle.