Patent GB-605188-A (GB)
Title: Improvements in or relating to self-controlled projectiles
IPC: F41G7/22
Filed: 1944-05-24
Abstract: 605,188. Automatic control systems for projectiles. SPERRY GYROSCOPE CO., Inc. May 24, 1944, No. 10108. Convention date, Jan. 8, 1943. [Class 38 (iv)] [Also in Group XL (c)] A self-controlled projectile or aerial torpedo adapted to steer itself into a stationary or moving target is provided with radio sighting means comprising a generator of periodic pulses of electromagnetic energy, directive radiating or scanning means for projecting the energy about a conical angle of space, means for receiving the corresponding echo signals from a target located within the conical angle, means for interpreting the echo signals and producing voltage signals dependent on the angular displacement of the line of sight with respect to the axis of the radiator, and control means responsive to the signal voltages for continuously realigning the axis of the radiator with the line of sight. The projectile may be released from a carrier aircraft provided with indicating means such as a cathode-ray tube connected by detachable leads to the projectile and controlled by the echo signals received by the latter so that the pilot of the aircraft may initially align the projectile with the line of sight before releasing it. A control oscillator 8 on the projectile, providing a voltage of a frequency that may be within the audible range, is connected to a pulse generator 10 which converts the substantially sinusoidal oscillations into pulses of the necessary shape, magnitude and duration, having a repetition rate equal to the oscillator frequency. Trigger pulses from the pulse generator 10 are fed to a pulse transmitter 12 and trigger an ultra highfrequency generator producing pulses which are fed along a wave-guide 13 to a scanning radiator 14 comprising a rotating parabolic reflector 15 with its axis offset from the vertical so that when rotated by a motor 18 geared to the vertical lower end of a hollow supporting column 16 a conical scanning beam is produced. A twophase generator 24 with its shaft geared to the rotating column 16 provides through its output leads 25, 26 two A.C. voltages phase displaced by 90 degrees to provide a time reference for the spin motion, so that the instantaneous magnitude of voltage 26 may be taken to correspond at any time to the elevational component of the angle that the reflector makes with the spin axis 17. Similarly, the instantaneous magnitude of voltage 25 corresponds to the azimuthal component. Energy reflected from the target during intervals between successive transmission periods is received by scanning radiator 14 and passes in a reverse direction into a wave-guide 13<SP>1</SP> and through a limiter 34 to a receiver and detector 36, where the received pulses are amplified and detected and then fed to a detector and filter 37. The latter produces in output lead 41 a spin frequency voltage corresponding to the envelope of the pulses appearing on lead 38 and feeds it to an elevation phase sensitive amplifier 42 and azimuth phase sensitive amplifier 43 over leads 44, 45 respectively The amplifier 42 compares the phase of the voltage received over lead 44 with the elevation reference voltage received over lead 26 and produces on the output lead 6 a direct voltage corresponding in polarity and magnitude to that component of voltage 44 which is in phase with the reference voltage 26. In the same manner the amplifier 43 provides in the lead 7 a voltage corresponding to the component of the voltage 45 which is in phase with the reference voltage 25. These voltages corres. pond to the elevation and azimuth components of the error angle, i.e. the angle that the line of sight makes with the spin axis 17 and consequently with the axis of the projectile. The error signal voltages are amplified by amplifiers 46, 49 and fed to elevator servo system 48 and rudder servo system 50 respectively, which are thereby adjusted automatically as necessary. Specification 621,485 is referred to.